yun0251 在 2004-10-9 18:02:06 发表的内容
yun0251 在 2004-10-9 0:30:38 发表的内容
我的两张测试碟，有些功能不太会用。请高手们多多交流指导！[upload=jpg]Upload/20041090302798164.jpg[/upload] |
[rar]Upload/200410917593921727.rar[/rar][rar]Upload/200410917595252692.rar[/rar]
现将英文说明书附上，愿与大家交流。 |
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My Disc:
1.封底：
The Audio Industry's Choice for 25 years. Sheffield
Lab has been selected by many of the most respected
names in high-end audio manufacturing and testing to
create custom projects using the "Sheffield Sound."
Custom electronics throughout the entire recording chain, plus our
legendary "live to two-track" engineering, combine to deliver all the
musical excitement created by world-class musicians in live ses-
sions. Connoisseurs agree that Sheffield Lab recordings deliver
substantially greater transparency, phase linearity, and dynamic
range.
The best hardware demands the best software to fully reveal the
unique qualities of a manufacturer's technical expertise! Since our
pioneer direct disc recordings in 1968, audiophiles the world over
have relied on Sheffield to provide the musical source that is
the first component of a true high-end system.
2.内页：
p1-----------
Notes on the Technical Tracks
by Richard Clark, A2TB
The Sheffield Lab / A2.TB Test Disc is more than a test CD. The third in A2TB's
series of test software, "My Disc' was engineered for a thorough evaluation of
not only your cornponent's performance, but the listening environment, and
your personal critical listening ability as well. The disc contains music as well
as test signals that were designed and recorded so as to make "My Disc" your
one indispensable disc for critical system evaluation. The music selections
were chosen to cover a broad spectrum of styles so that nearly everyone can
find a music type suitable to their individual taste. The test selections were
recorded to cover a wide range of system design and performance evalua-
tions. Because your system's overall performance can be influenced by many
variables, this disc contains special tracks that enable you to analyze perfor-
mance, with or without specialized test equipment. Some of the tracks
are only useful with test equipment, but they are few and will be indicated
with a hand symbol (~). Whether you are an audiophile or a bench tech, "My
Disc" will prove to be your most valued disc. Even if you have specialized
equipment, you may find you don't always have it with you when you want to
evaluate a system - for instance, at a friend's house, in a show room, or even
at a car stereo contest. In order to demonstrate some of the effects on this
disc, we had to perform special processing on some of the musical tracks. The
first six tracks are direct digital transfers from the original roasters. These
tracks are intended for both reference and general listening evaluations. Notice
that after specialized processing, the same selections are later used in some of
the demos and tests.
p2-------------
Notes on the Music Tracks
by Quentin Libby, Sheffield lab
TRACK 1. ~Stranger In My Bed"
UP FRONT ~ THE POWER OF SEVEN (10033-2-F)
You should be able to define many different levels of percussion
intermingled with the keyboard work. Note the cowbells just behind
and below the lead vocal at all times. Listen to the back-up vocals as
they sing "1 got trouble..." at 1:12: can you pick out all 6 voices?
Remember, all these vocals and different instruments were recorded in real time -
your system should deliver some pretty intense SPL readings, so listen carefully!
TRACK 2. "Dish Rag"
I'VE GOT THE MUSIC IN ME ~ THELMA HOUSTON & PRESSURE
COOKER (10002-2-M)
The 1975 original direct disc LP version of this project sold more than
a quarter million copies before exhausting the masters, and is widely
credited with starting the entire audiophile recording industry. During
the opening 30 seconds, notice how well you can distinguish the individual voices of
the two keyboards. Then notice the vertical lift in the entire sound as the homs come
in overthe keys. Can you hear the tambourine (panned far left) from :29 to :42? See if
your system does a good job of properly staging the trumpets (predominantly in the
leff channel, eg. 1:13), with the ~fat" lower sound of the trombone on the right (refer-
ence the trombone solo at 1:29).
TRACK 3. "Dance of the Knights1" from Prokofiev's Romeo & Juliet /
THE LEiNSDORF SESSIONS, VOL. 1 (10043-2-G)
Los Angeles Philharmonic, Erich Leinsdoff conducting
Recorded on the legendary MGM Sound Stage One. You should be
p3------------
able to recreate the orchestra sitting in a semi-circle around you: the concert grand in
the upper left corner of the stage, the violins and cellos in front followed by the wood-
winds further up towards the back of the stage and on a higher elevation and in the
very back rows, the trombones, and percussion (including the massive timpani
drums). Notice in the first 20 seconds how the sound "seesaws" front to back between
the violins and cellos. Beginning at 8:27, in the upper left corner of the stage, notice
the sharpness of the tight drum rolls, punctuated by the raspy horns and strings.
TRACK 4. "Dirty Blue"
THE NAME IS MAKOWICZ ~ ADAM MAKOWICZ, WITH PHIL WOODS
(10021-2-V)
aB
Notice the presence of the vibes, even with the busy and intricate
piano work. Listen in the transition between notes at 1:07, as six leg-
end Phil Woods bites down and changes the sound of the note. At
the end of the track, Woods steps back and swings around, points the horn upstage
and center to guide the band out.
TRACK 5. "Wishing Well"
SPEAKING IN MELODIES ~ MICHAEL RUFF (10035-2-F)
lB
Here's what Sheffield chairman and mastering engineer, Doug Six,
has to say about this track: "Sheffield's own pre-amps and line level
mics really shine through. Notice the clarity of the piano, the natural
but extended cymbals, the clarity and warmth of the vocals. Notice the astonishing
percussion presence, without artifact, a combination of Coles ribbon mics into a GML
transformerless pre-amp. I am extremely proud of the sound we achieved on this pro-
ject."
TRACK 6. "Dock of the Bay"
LINCOLN MAYORGA & DISTINGUISHED COLLEAGUES, VOL. III
/
(10001-2-V)
This was actually a bonus track on the CD version: During rehearsals
for the original direct disc recording sessions, the dynamics of Jim
Keltner's kick drum were so extreme, that groove excursions from the
cutting lathe became toe wide to fit on the album side. The song had to be eliminated!
What you hear on this track is an actual rehearsal take, with the band beginning to
block out parts and solos. When the guitar comes in at :57 with fairly equal force in
both channels, you should really get a tremendous sense of stereo separation and
"liveness" around the instruments. At 1:33 the horn comes in on the right channel; if
you are listening in your car, the hornplayer sounds like he is sitting right about on top
of your glove box. Notice the somewhat crude-sounding fade at the end of the cut:
When recording in 1973, they mixed with fader knobs the size of your steering wheel!
Technical Tracks (continued)
TRACK 7. A 1 kHz sine wave at -20 dBFS. This tone is useful as a reference level
when interfacing A-to-D or D-to-A converters. A level of -20 dBFS is a nominal level
that permits 20 dB of headroom. This level is normally used in digital systems to indi-
cate "0" level on normal program material. Although reference levels as high as -14
dBFS are used, -20 dBFS is the most common. Conversion to other levels is easily
done from the tone on this track.
TRACK 8. A 1 kHz sine wave at O dBFS. This tone represents the highest level signal
that can be recorded in the CD medium. This maximum signal is useful for checking
the output level of other devices interfaced to the CD player as well as for optimizing
the overall gain structure of a complete system.
TRACKS 9-18. A quick check for acoustic response. The following tracks are intend-
ed for an evaluation of the acoustic response of both headphones and loudspeakers.
Although the signals are sine waves, they have been warbled and their effective band-
width is one full octave. The purpose of the warbling is to eliminate the effects of
standing waves that would othen~ise occur with pure sine waves. Each track starts
with a 1 kHz reference tone with a duration of one second. The warble lasts for three
seconds. In an ideal system, all of the multi-frequency warbles should match the 1
kHz reference warbles in loudness. The complete sequence will allow a generalized
evaluation in less than 40 seconds. The sequence is
RACK 9:20 Hz; TRACK 10:62
Hz; TRACK 11:125 Hz; TRACK 12:250 Hz; TRACK 13:500 Hz; TRACK 14:2.5 kHz;
TRACK 15:5 kHz; TRACK 16:10 kHz; TRACK 17:15 kHz; TRACK 18:19 kHz.
TRACK 19. This track is a recording of a person simply counting from 1 to 25.
Although it may be normal for some of us to evaluate systems by listening to musical
instruments, others may experience difficulty. We are all human and know what a per-
son sounds like. Although you may not know the person doing the counting, your
sound system should lead you to believe that he is real and in the room with you.
Even though the bandwidth of a human voice is not as wide as some instruments,
you'll find that vocal realism is net trivial. Choice of microphone type can certainly
effect a demo such as this. In order to minimize coloration, we used a R & K instru-
mentation microphone placed close to the announcer in a very diffuse room. The
omni-pattern helped to minimize proximity effect. A great use for this track is in sys-
tems designed to cover large areas such as sound reinforcement systems, PA sys-
tems, etc. By putting this track on repeat and playing it as you walk around the room,
information regarding the evenness of coverage and the intelligibility of the speech
can be easily evaluated.
TRACK 20. An identification track for the right channel
TRACK 21. An identification track for the left channel.
TRACK 22. This track is a quick check for relative polarity between the left and right
channels. When the voice says that it is in phase, the image should be coherent and
in the center of the stage. When the voice says, "1 am out of phase." it should appear
diffuse, lack fccus, and Jose iow frequency response. If your system does just the
opposite, then one of your channels has reversed polarity. Although the most common
source of this error is with the speaker connections, other sources of error should not
be ruled out. Balanced interconnects can be a source of polarity problems,
~-TRACK 23. This track contains polarity pulses. These pulses are wide enough in
duration to enable them to be used with most makes of polarity checking devices. The
pulses have been sequenced so as to eliminate invalid readings. Each group of three
positive poises is followed by a single negative pulse. The sequence is repeated for
one minute. The fourth pulse of each group must show opposite polarity in order for
the reading to be considered as valid,
~TRACK 24. A 1 kHz sine wave is again presented, but this time with the bottom half
clipped. This track is very useful for the bench technician who needs to track phase
throughout a component or throughout an entire system. The clipped sine wave can
be spotted instantly with an oscilloscope. This tone can also be used when making
recordings to quickly check the recording polarity as well as the polarity of other stor-
age systems.
TRACK 25. This track contains a recording of three people describing their Iccation
within the sound stage. If your system can not fulfill the descriptions defined by the
voices, then your system is NOT reproducing a correct stereo image.
TRACK 26. This track contains the same information as track 25 except that all three
s
people are talking simultaneously. Just as if three people were talking at once, your
system should not mix them together. You should be able to clearly identify each indi-
vidual in his or her location. You should be able to understand each individual and
concentrate on what each individual is saying while mentally tuning out the other two
announcers. This is a particularly difficult test for a sound system, but is very reveal-
ing. If you are unsure as to how well your system handles this track, try comparing it
to the real thing. Have three talking friends stand across the front of your listening
room and repeat this test for yourself.
TRACKS 27-32. These tracks contain a specially processed music selection for eval-
uating accuracy and focus of the lateral sound stage.
TRACK 27. (stereo) This track is recorded in normal 2-channel stereo.
TRACK 28. The music is switched to mono (L + R). At this time the sound stage
should totally collapse. The left and right speakers should audibly disappear and all of
the music should appear to come from a location in the center of the sound stage.
There is no difference in the amplitude or phase information in the left and right chan-
nels when the system is in mono. A system that is working propedy will create the illu-
sion of a single speaker in the middle of the sound stage even if there is no center
speaker. If there is no center speaker, this illusion is known as a phantom center. Our
ability to perceive a phantom center is the basis for the entire stereo recording
process. Lack of a clearly focused image or the presence of a wandering image is a
result of frequency selective steering and indicates an inability to project a proper
stereo image.
TRACK 29. The mono signal is fed to the left channel only. At this time the image
should not change its apparent spectral balance, sharpness of focus, or any other
sound qualities. Only the image should shift to the left channel.
TRACK 30. The image shifts back to the center for comparison. Once again the
sound qualities should not change; however, the apparent source of the sound should
change.
TRACK 31. The mono signal shifts to the right channel only. Again, only the apparent
location of the sound should change.
TRACK 32. The signal is switched back to stereo and the entire sound stage should
appear with no changes in volume, spectral balance or any of the other sound quali-
ties. This is a very difficult test for all but the best systems in ideal listening rooms con-
taining a defined listening location. It is, however, fundamentally critical if good stereo
imaging is the goal.
TRACK 33. This track contains a 45 second sampie of music recorded at a normal
transfer level. It is to be used as a reference for the following tracks 34 through 40. In
each of the successive tracks the record level has been reduced in increments of 10
dB. Playing these tracks while subsequently increasing the volume for each track will
give an indication of the ability of your system to accurately resolve Iow level signals -
the most difficult task for digital systems. This is an excellent test to demonstrate the
quality of D-to-A converters. The farther your system can go without excessive noise
or distortion the better. Even track 40 at -70 dB, can be clearly heard on an excellent
system.
TRACK 34. Recorded with transfer level -10 dB.
TRACK 35. Recorded with transfer level -20 dB.
TRACK 36. Recorded with transfer level -30 dB.
TRACK 37. Recorded with transfer level -40 dB.
TRACK 38. Recorded with transfer level -50 dB.
TRACK 39. Recorded with transfer level -60 dS.
TRACK 40. Recorded with transfer level -70 dB.
TRACK 41. This track is a recording of digital black or 0 bits. ideally this track should
be reproduced as total silence. This track can be used for evaluating the noise floor of
components or a system.
w'TRACK 42. This track contains a high frequency, Iow level signal that alternates
between 0000 and FFFF. Nothing should be audible on this track. This signal is useful
for evaluating digital circuits and their possible interaction with analogue circuits within
a CD player. Useful only with proper test equipment.
TRACK 43. Correlated pink noise 20 Hz to 20 kHz. (The exact same noise informa-
tion in each channel.)
TRACK 44. Uncorrelated pink noise 20 Hz to 20 kHz. This track is recorded with
uncorrelated pink noise. When equalizing any multi-channel system (stereo), it is
always best to compare the results with correlated (mono) and uncorrelated (stereo)
noise. If the listening position is not equidistant between the loudspeakers, the best
results can be obtained when a good compromise is found between these two mea-
surement signals.
TRACK 45, Intended as a track for demonstrating the concept of dBs. While many
audiophiles know what a dB is and may discuss dBs all the time, very few of them
have access to precision stepped attenuators and have virtually no perception of a
dB. One dB is a tenth of a Bell. One dR is normally considered to be the smallest
amount of level change that can be easily detected by the average listener. This track
demonstrates level changes in 1 dB steps. Pink noise is raised in one dB steps every
three seconds. Notice that the actual change in each step is very small, yet the overall
level can be easily perceived to increase.
TRACK 46. Similar to track 45, except that in this track there are four steps in 3 dB
increments. Remember that each step requires twice the power of the preceding step
- even though the perception of change is still small
TRACKS 47-56. These tracks contain pink noise that has been filtered into succes-
sive 1/3rd octave bands starting with 25 Hz. Each track contains three 1/3 octave
bands that constitute an octave. The tracks are as follows:
Track # Frequency Centered at
47 25 31.5 40
48 50 63 80
49 100 125 160
50 200 250 315
51 400 500 630
52 800 lk 1.2k
53 1.6k 2k 2.5k
54 3.15k 4k 5k
55 6.3k 8k 10k
56 12.5k 16k 20k
These filtered bands can be very useful for measuring system tonal balance - espe-
cially if you don't have access to an RTA (Real Time Analyzer). Each band can be
measured on a simple sound level meter {SLM) and the value plotted on a chart to
obtain a response curve. These bands are also useful for final listening evaluations.
When reproducing these bands, especially the highest ones, the system should repro-
duce each band in the center of the soundstage. Final system tweaking, on a band by
band basis, will produce a more stable stereo image.
TRACK 57. This track contains a 20 Hz to 20 kHz continuous warble for subjectively
evaluating the overall smoothness of the acoustic response in a listening area. This
sweep has been warbled to eliminate the standing waves that would normally occur
with a simple swept tone. This track is a continuous sweep that contains all frequen-
cies from 20 Hz up to 20 kHz. Any obvious peaks or dips will be evident on this track.
TRACK 58. This track is a warble from 100 Hz to 20 Hz for the quick subjective evalu-
ation of subwoofer systems. Response on a good system should be strong down to
the lowest frequencies (20 Hz) which cccur at the end of this track.
TRACK 59. This track contains individual frequencies from 10 Hz to 99 Hz. Each fre-
quency lasts for 5 seconds, if your CD player displays index numbers, each index
number signifies a decade of frequencies. They are as follows:
Index.' Frequency:
1 10-19
2 20-29
3 30-39
4 40-49
5 50-59
6 60-69
7 70-79
8 80-89
9 90-99
These are Iow distortion sine waves and should be useful for finding the resonant fre-
quency of Iow frequency drivers, evaluating standing waves in a room, testing for
buzzes and rattles, etc.
TRACKS 60-62. These tracks collectively contain a very flat, Iow distortion 2O-2OkHz
sweep for testing the frequency response of electronic components. It is not intended
for acoustical evaluations where reflections or standing waves may cause inteder-
ence. Such acoustical measurements are better done with warble sweeps or noise
tracks. Track 60 sweeps from 20-200 Hz, track 61 sweeps from 2O0-2kHz and track
62 sweeps from 2k-20kHz.
TRACK 63. This track contains the musical note A (440 Hz). This could be used as a
reference to tune instruments or even check the accuracy of your CD player's speed
to a tuning fork if you suspect a speed problem. If you have confidence in your player,
you can check your tuning fork, or you can use your CD player to tune your instru-
ments. You can also compare two players. Yes, problems can occur - even with digi-
tal!
TRACK 64. This track contains a 100 Hz tone burst. The burst has a duty cycle of
25%. The power between bursts is 1/100th of the burst power. This track can be use-
ful for checking the dynamic characteristics of amplifiers, speakers, and especially the
power supplies of amplifiers. It is also useful to measure the voltage drop in 12 volt
automotive systems when tested at high power.
TRACK 65. This track is the same as track 64, except it is at 1 kHz.
TRACK 66. This track is the same as track 64, except that it is at 10 kHz. Be careful
because this track can easily damage tweeters.
,e-TRACK 67. This track is a 100 Hz square wave. It is useful for evaluating certain
performance characteristics of components with test equipment. Good square wave
pedormance requires bandwidth in excess of 1/10th to 10 times the fundamental fre-
quency in order to produce an undistorted wave form. Good reproduction of a square
wave requires good frequency as well as phase response. This signal can be used for
examining the Iow frequency performance of equipment to the lowest audible frequen-
cies, i.e. below 20 Hz. Square waves are also useful for evaluating dynamic charac-
teristics (especially of filters and loudspeakers) where errors show up as overshoot
and ringing.
~-TRACK 68. Same as track 67, except at 1 kHz.
TRACK 69. This track contains the full dynamics of the original recording and is
intended to be a musical reference track for the following track. Besides a listening
comparison of dynamic compression this track along with the following track can be
used to check the accuracy of peak meters. Notice the highest reading displayed by
your meters when playing this track. Then without changing the volume level, com-
pare that reading to the reading measured on the next track. The difference between
the two is the inability of the meters to respond fast enough to very short duration
musical transients.
TRACK 70. This track is part of a dynamic evaluation and it is recorded with exactly
the same peak levels as the preceding track. However, it has been compressed
dynamically. The process of dynamic compression is very common in modern record-
ings and is done to make the recording appear to be louder - at the expense of
dynamic range. If this track sounds better than the preceding track, your system may
lack the power and dynamic capability to fully reproduce the transients of the best
audiophile recordings.
TRACK 71. This track tests the radiated distortion characteristics of your system. A
sine wave from an Audio Precision System One was processed through a special
device that enables us to regulate the amount of distortion desired. The initial signal
started with about .0004% distortion. It was processed and recorded on track 71 as a
reference for the following tracks. On this track the tone has about .03% distortion. In
each track following, the distortion is raised by a factor of about 10 dB. If you have a
distortion analyzer, you can check its calibration as the distortion on the following
tracks is very precise. Of course, if you have a noisy CD player, or a poor D-to*A con-
verter the THD+N may affect the lowest reading of this series of tests. If you don't
have a distortion analyzer, you can use these tracks as a masking test. The concept
of masking is simple. By starting Out at Iow levels and increasing the distortion until it
is just audible, you have an indication of the distortion threshold of your system or
your ability to perceive it. Start with track 71. If you are unsure of what distortion
sounds like, skip to track 76 because track 76 has exactly 10% distortion and should
be clearly audible to anyone on even a terrible system. Distortion is the slight buzz
mixed in with the pure tone. If you can't tell the difference between any of the tracks,
the distortion of your system is very high (over 10%) or your hearing is very bad
(you've been in car audio too long). Most people can easily hear 1% distortion on a
good system with sine waves.
TRACK 72. Same as track 71, except with .1% distortion.
TRACK 73. Same as track 71, except with .3% distortion.
TRACK 74. Same as track 71, except with 1% distortion.
TRACK 75. Same as track 71, except with 3% distortion.
TRACK 76. Same as track 71, except with 10% distortion.
TRACK 77. This track begins a test identical to the previous test, except the test sig-
nal is music. At this point we would like to point out that the distortion processor
affects all frequencies equally and is not affected by level. Therefore this test is more
revealing than a component that has frequency or level dependent distortion. We
have found that with music material, some people can hear 3% distortion on a good
system but hardly anyone can detect 1% distortion. However, 10% distortion should
be obvious on all but the worst systems.
TRACK 78. Same as track 77, except with .1% distortion.
TRACK 79. Same as track 77, except with .3% distortion.
TRACK 80. Same as track 77, except with 1% distortion.
TRACK 81. Same as track 77, except with 3% distortion.
TRACK 82. Same as track 77, except with 10% distortion.
TRACK 83. This is a musical selection with no added delay and is intended to be a
reference for the following track. Much has been said and written about the effect of
arrival times on the quality of music reproduction. Many times this error is evaluated
along with other errors that make its real importance hard to determine.
TRACK 84. This music selection is a demonstration of group delay. The signal was
run through an all-pass filter with a total delay at Iow frequencies of about 7 millisec-
onds. This would equate to a loudspeaker offset below 100 Hz of nearly 7 feet with
respect to the rest of the audio band. This circuit is able to introduce large amounts of
delay in the time domain while having virtually no effect in the frequency domain. After
you have listened to these two tracks, have someone switch between the two several
times without identifying the track. Determine for yourself just how audible time delay
distortion is to you.
NOTE: The effects intended to be demonstrated by the following tracks lose
most of their effectiveness unless listened to with headphones or specially
designed loudspeakers properly positioned. (See footnote).
The following tracks were included to demonstrate some of the principles that enable
us to localize sounds and perceive our surroundings. Since its very beginning, stereo
has done a great job of defining a lateral sound stage. The ability to completely sur-
round us has net been a major goal until recently.
These tracks demonstrate an interesting recording technique using a process known
as "In The Ea~' (ITE) recording. This process utilizes a small pair of laboratory probes
less than 1/16" in diameter, spaced about .050" from each eardrum of a human listen-
er. Using this procedure, the transfer function of the head, ear canal, and pinnae are
encoded into the recording. When listened to on a system with greater than 20 dB left-
to-right separation (acoustic as well as electrical), the sense of space, direction and
ambience is captured with stunning realism. Even sounds that occur behind you are
accurately placed. Be advised that the acoustic separation requirement virtually
rules out almost all conventional stereo loudspeaker placement schemes.
Conventional systems can reproduce the lateral sound stage but they usually lack the
ability to convey depth and height. Most of this problem is due to an effect known as
inter-aural cross correlation. This is caused when the left ear hears the dght speaker
as well as the left speaker, and the right ear hears the left speaker as well as the right.
The recordings were made on Pit Row during the 1994 time trials at the
Indianapolis Motor Speedway (how's that for a big sound stage?) and are excerpts
from an entire afternoon of recording.
TRACK 85. You are standing between Roger Penske's pits and the main straight-
away. Emerson Fittipaldi's crew is behind and to your left, and Jacques Villeneuve's
crew is adjusting the air pressure in his tires behind and to your right. As a car passes
in front of you on the straightaway at over 220 mph, Emerson starts his car and drives
away.
TRACK 86. At the start of this track you experience a short walk down pit row. The
race track is to your right and the pits are on your left. The race cars come from
behind and pass on your right. The position of the announcer appears to move
because you are walking between speakers spaced about 50 feet apart. We were try-
ing find one of the new Mercedes engines to record its sound and you hear Don on
your left say, "Here's the one we want." We are trying to keep from getting run over as
cars are everywhere. We are then warned of a car coming into the pits. You can hear
the car of Villeneuve drive up and stop less than 6 feet behind you, just before the air
jacks raise it off the ground.
Footnote: For information ~nceming loudspeaker placement for reproduction of ITE recordings contact
Syn-Aud-Con
2730 W. Counb/Rd.
l OO North
No~n, IN 47264
(812) 995-8212
A special thanks from A2TB to Sheffield Lab and especially to Doug Sax and Oscar
Ciornei for allowing us to use their excellent recordings for "My Disc". Thanks also to
Oscar for suggesting the project to us, and for coming up with the name, "My Disc!"
Thanks to Ray Evans for Sheffield Lab art direction. Thanks to the following for techni-
cal help in the production of this disc: Patdck Poovey, David Navone, Ellen Threatt,
Brian Smith, David Clark, Don and Carolyn Davis, John Royer, Phil Hochriter and
Howard Hoyt.
┌─────┐
│,xlU~OS~~~│
└─────┘
About A2TB and Autosound 2000
David Navone, a physicist by education and long-time troubleshooting columnist for
several trade and consumer magazines including Car Audio and Electronics
Magazine, and Richard Clark, pro audio engineer and competitive autosound champi-
on, co-publish Autosound 2OO0 Tech Briefs
(A2TB), a monthly subscription-only techni-
cal oriented newsletter. Besides their innov-
ative software and the A2TB newsletter,
David and Richard conduct seminars on the
subjects of component design, acoustics,
psycho-acoustics, system design, recording, software manufacture, and much more.
Each year they conduct dozens of technical seminar/workshops worldwide. Over the
past five years, their teaching and technical innovations have literally revolutionized
the high-end car audio industry. Richard and David also serve as technical consul-
tants to many manufacturers in the car, home and pro-audio industry. If you are inter-
ested in engineering data, test reports, and detailed graphs concerning the technical
"nuts and bolts" of audio and auditory perception, Richard and David can be contacted
by calling 910-570-0341. I1 you're interested in a subscription to A2TB, please call
800-548-8200.
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XLO:
TECHNICAL TRACKS RX-1000
1 Channel Identification (Left/Right) o:3o
2 Voice In-Phase 0:J1
3 Voice Out-of-Phase o..25
4 Clap Track 0..59
5 315 HzTestTone 1:15
6 "Prof." Johnson Does Something Spatial 4:19
7 Demagnetizing Sweep 0:57
8 Demagnetizing Fade 1
o
9 System Burn-in 15
o ii!.?!iiii~illI
MUSIC TRACKS
10 Mono, In-Phase 1:53
11 Mono, Out-of-Phase 1:53
f
12 Stereo, Out of Absolute Phase 1.53
13 "Stormy Weather" 6.'40
Eileen Farrell, vocal / Loonis McGIohon combo
14 "Shiny Stockings" 5:23
Bob Lark / DePaul University Jazz Ensemble I
15 Morton Gould: Derivations, "Rag" movement 2:19
John Bruce Yeh, clarinet / DePaul University Jazz Ensemble I
16 Jan6cek: Sinfonietta, "The Queen's Monastery" 5
l
Jos6 Serebrier / Czech State Philharmonic
17 Franz Biebl: "Ave Maria" 5:55
Timothy Seelig / The Turtle Creek Chorale
18 Weinberger: "Polka and Fugue" 7:49
Frederick Fennell / Dallas Wind Symphony / Paul Riedo, organ
Track I Stereo Channel Identification and Channel Balance
Channel Identification. For System set up. Allows you to verify that your
System's Right and Left channels are properly connected, and not reversed.
Channel reversal, either from a single source or from all sources (CD, LP,
tuner, etc.) can easily come about as the result of mistakenly plugging just
ONE pair of cables into your System in reversed order (Left-channel plug
into Right-channel jack, and vice versa).This sort of problem is most common
in cases where new equipment is added to an existing System, old equipment
is removed and replaced, or, for A-B comparisons, equipment is temporarily
plugged into the System and then removed. Always check for channel fever-
sal if you have been making changes to your System.
Channel Balance. Particularly for recordings made using a "coincident"
microphone technique (which eliminates phase differences at the microphone
position), having your System's channels precisely in balance is crucial for
correct imaging and spatial representation. This mono channel balance test
provides phase-correct AMPLITUDE ONLY information to enable you to
achieve near-perfect channel balance "by ear".
NOTE: Use this track for balancing two channel stereo ONLY. When the
systems are set to operate in any surroundsound mode, the steering logic
routes all of any mono signal to the CENTER channel, only, and bypasses the
RIGHT and LEFT channel speakers. This means that the signal will always
come from the exact center (the center channel speaker), regardless of the
Balance Control setting, and makes true channel balance setting impossible.
Relative PhaseTest: Track 2 In-phase
Track 3 Out-of-phase
AN "IN-PHASE/OUT-OF-PHASE" RECORDING OFTHIS TYPE ISTHEVERY
BESTTOOLYOU CAN USETO MAKE SURE YOUR SPEAKERS ARE PROP-
ERLYWIREDAND PROPERLY PLACED. IT CAN EVEN HELPYOUTO
IMPROVE THE ACOUSTICS OF YOUR LISTENING ROOM!
A. Properly Wired
As applied to loudspeakers, the term "Relative Phase" refers to the move-
ment of the speaker system's driver elements (usually cones, domes, panels
or ribbons) in response to a signal of known polarity. If the elements of both
the Left and Right loudspeakers move IN THE SAME DIRECTION [forward]
for a given [positive] signal, and do so at the same time, the speakers are IN
correct relative phase. If they move in OPPOSITE directions (one forward,
one back), they are OUT OF correct relative phase.
The result of speakers being out of relative phase is that imaging specificity
is lost and, because the Right and Left channel woofers at least partially can-
cel each other, bass energy and volume are greatly reduced. If this is NOT
what you hear when you play the OUT OF PHASE section of this track; if,
instead, you find that the OUT OF PHASE section images BETTER than the
IN PHASE section, or that Roger Skoff's voice has more bass content OUT
OF PHASE than it does IN PHASE, there's something wrong with your
~ - -rem, and the odds are that ONE of your loudspeakers is wired incorrectly.
~x it, check your speaker cables at both their amplifier and loudspeaker
ends. When you find the end that has its leads hooked-up POSITIVE to
NEGATIVE and NEGATIVE to POSITIVE, instead of POSITIVE to POSITIVE
and NEGATIVE to NEGATIVE, as they should be, just re-make those connec-
tions, and your problem will disappear.
B. Properly Placed
The cancellations that result from an "out-of-relative-phase" condition can
help you "dial-in" the positioning of your loudspeakers easily and precisely.
WHEN PLAYING IDENTICAL OUT-OF-PHASE SIGNALS, PERFECTLY
MATCHED LOUDSPEAKERS, PERFECTLY PLACED, IN A PERFECT LISTEN-
ING ROOM,WILL PERFECTLY CANCEL ALL OF THE SONIC I NFORMA-
TION WHICH WOULD NORMALLY APPEAR TO COME DIRECTLY FROM
THE SPEAKERS, OR FROM BEHIND OR BETWEEN THEM.THE ONLY
SOUNDTHATWlLL BE HEARDWlLL BE FROM UNCANCELED ENERGY
REACHING THE LISTENER INDIRECTLY AS WALL, CEILING, OR FLOOR
REFLECTIONS,AN D THIS WILL SEEM TO HAVE NO APPARENT SOURCE.
Although none of the above "Perfects" may actually be possible to achieve
in the real world, it IS possible to come close, and by doing so, you will
GREATLY improve your System's soundstaging, imaging and focus.
Start by positioning your speakers as weft as you can "by ear" and by using
the appropriate other tracks on this CD. Then, after making sure that the
channels are balanced correctly, sit exactly in the "sweet spot" (usually dead
center, between your speakers), and play the OUT OF PHASE section of this
track. Listen carefully: Where does the voice sound like it's coming from? If it
seems to have a definite source, move ONLY the speaker nearer to the appar-
ent source a SMALL DISTANCE (less than an inch may be sufficient) farther
away from you. What does that do to the sound when you play the :rack again?
Keep repeating the process, moving your speakers ONE AT A TIME, IN
SMALL INCREMENTS, forward, backward, to the sides, or at slightly different
angles to your listening position, until you have gotten as close as you can to
the ideal no-image"sourceless" sound. Then change your listening position,
slightly out of the sweet spot, and start all over again. When you've gotten
the greatest cancellation possible at the broadest possible range of listening
positions, you're finished! Put on one of this CD'S Reference Recordings
audiophile-quality music tracks, and prepare to have your socks knocked off!
C. Improving Listening Room Acoustics
After you have canceled as much as possible of the direct sound from your
speakers, a substantia[ part of the sound that remains will be the result of room
reflections. These reflections can be caused by any acoustically hard surface,
including walls, uncarpeted floors, untreated ceilings, window glass, mirrors,
pictures, and even some furniture, and can come from anywhere at all in the
room above, below, to the sides of, or even behind your listening position.
Although a certain amount of"liveness" is to be desired in a good listening
room,/ herent reflections reaching the listening position can only hurt imag-
ing ar~ ,minish the quality of spatia[ representation. To eliminate them, the
first si ~ is to FIND them, and that's how this track can help you.
Seated in your normal position, play the OUT-OF-PHASE portion of this
track and listen carefully to locate the sources of reflected sound. These are
the acoustical "problem spots" in your room, and once you've identified
them, you can apply whatever acoustical treatments may be necessary.
Remember, though, that every time you make an acoustical change, you
MUST re-check the placement of your speakers for optimum cancellation.
Track 4 "Clap Track" for Acoustical and Loudspeaker Evaluation
When Recording Engineers or Acousticians enter a new studio or listening
environment, the very first thing most will do is to move around the room
clapping their hands. The purpose of this is to learn the room's "sound", and
get an idea of the kind, intensity and duration of its echoes. This is useful
information, and constitutes much of the basis for any plan for either effec-
tively using or acoustically treating the room.
A problem, though, with walking around a room clapping your hands is
that as you walk around, the clapping--your "test signar'---walks around
WITH you, and you get inconsistent"readings',Another problem is that NO
TWO HANDCLAPS SOUND EXACTLYTHE SAME, so differences heard at
two different points in the same room MIGHT be the result of different
acoustics, or they MIGHT just be the result of different-sounding handclaps.
Without further testing, THERE'S NO WAYTO TELL.
This track solves both of these problems, and gives you one of the most
useful tools available to quickly evaluate both your room acoustics and the
directional characteristics of your loudspeakers. Multiple repetitions of the
same ONE HANDCLAP are recorded to give you total consistency of both
source and signal, so that, as you listen from different points in your room,
you can be CERTAIN that any differences you hear result from inconsisten-
cies in the acoustics of your listening room, or frequency-related differences
in the dispersion patterns of your loudspeakers.
NOTE
o ensure that any reflected sound you may hear is from your own
listening room, and not the studio this track was recorded in, the normal
echo "tail" of the handclap has been digitally edited. This provides the sonic
equivalent of a handclap in an anechoic chamber, and explains why the clap
may sound more like a"snap" than a normal clapping sound.
Track 5 315 Hz. System Setup and Balance Tone
Although setting channel balance or overall volume level "by ear" is sufficient
for most purposes, there are times when the ability to set levels EXACTLY
can be of value, One of these is when setting-up speakers or dialing-in
room acoustics, using TRACK 3 of this recording. Another is when doing
A-B comparisons of different components: because whichever component
is LOUDER is usually perceived as being BETTER, it's absolutely ESSENTIAL
for accurate evaluation that the auditioning playback levels for both
components be EXACTLYTHE SAME.
The use of this track and a simple digital multimeter {available at most
electronics supply stores for around $30) will allow you to set levels very
precisely--usually to within one millivolt!
To check channel balance, set the multimeter to read AC Volts, and adjust
the SCALE to either 2VOLTS or 20VOLTS, whichever is available. On
"autoranging' multimeters, this adjustment will be made automatically. While
playing this track ATYOUR NORMAL LISTENING VOLUME, touch the multi-
meter's two test leads to the LEFT CHANNEL speaker outputs of your
amplifier (RED to POSITIVE and BLACK to NEGATIVE ~GROUND]) and
notice the reading of the meter (0.915 Volts, for example). Now transfer the
test leads to the RIGHT CHANNEL speaker outputs, play this track again,
and adjust the balance control to bring the right channel output to the same
reading as the left. Keep checking and re-setting BOTH channels until the
readings for both are identical.
NOTE: If, after perfectly matching your System's LEFT and RIGHT channel
electrical output levels, the sound you hear at a dead-center listening position
is still not perfectly centered, the cause may be differences in the sensitivity
or directionality of your loudspeakers, differences in speaker placement, or
differences in the right- and left-side acoustics of your listening room. See
other sections of this booklet for help in solving these problems.
To match levels for component evaluation, the procedure is similar to the
above: measure the output of component"A' at the amplifier terminals, (just
one channel will usually be sufficient),get a reading, then switch to compo-
heat"B", and set your output level to the same figure as for"A'.
Track 6 Prof. Johnson Does Something Spatial
Keith Johnson, Reference Recordings guru, and one of the inventors of the
HDCD process, is one of the most renowned recording engineers alive today.
Both erudite and articulate, "Prof," Johnson has strong opinions about practi-
cally everything in audio, and more than sufficient credentials and spectacular
successes to back them up. One of the things he feels most strongly about is
microphones--which ones to use, how many, and where to place them.
Although current "purist" thinking dictates just one pair of microphones for
every application, Keith Johnson knows that to limit yourself to just a single
approach to any recording problem is to ignore the realities of the sound
source, the recording environment and the program material.
The perfect proof is this track, recorded in Studio "A' at Fantasy Studios
in Berkeley, California. Because most commercial recordings made today are
multi-mono "mix-downs" (NOT true stereo), with instrumental or vocal
positions "panned'-in, and electronically-generated reverb added later, most
commercial recording studios tend to be on the dead side, acoustically.
Except for sources very close to the microphones,"Purist" rniking in this kind
of venue produces little more than a featureless "blob" of sound, with little
left-right differentiation and practically no sense of depth or indication of
room size.
To counter this problem, Keith chose a"Stereo Field" talking technique,
employing a total of six microphones: two of the famous Coles"BBC ribbon"
bi-directionals, positioned in Blumlein 45/45 configuration; two crossed
Sennheiser FM cardioids for front left-right"enhance"; and a pair of
Sennheiser FM omnis, mounted high, near the back wall, for retrieval of the
natural ambience of the room. The result? Even in a "dead" studio environ-
ment, an imaging and soundstaging tour de force and a real, verifiable test for
your System and set-up! Add to that "Prof." Johnson's own graphic illustration
of what can happen when multi-talking is used incorrectly, and you've got
one of the most useful tracks on this entire disc.
Track 7 Demagnetizing sweep
Recording Engineers have long been aware that a build-up of residual magnet-
ism can affect the sound of a playback system, and since the earliest days of
analogue recording on tape, regular de-magnetization of tape heads~rior to
every us~-
q~as been standard studio practice.
For tape recording, magnetic buildup is to be expected--tape is, after all, a
magnetic medium, and tape heads rely on magnetism to operate. In recent
years, however, it has also been learned that phono cartridges and even such
apparently non-magnetic elements of a playback system as its copper internal
wiring and circuit board traces, component mounting leads, crossover induc-
tors, connectors, cables and loudspeaker voice coils can and do become
magnetized and result in an audible degradation of system sound quality.
This magnetization comes about because wherever there is a flow of elec-
tric current, an electromagnetic field is formed around the conductor, which, if
it is made of or contains magnetizable metals (iron, nickel and cobalt--the
"iron triad"),will tend to leave the conductor with a residual magnetic charge.
The leads of many capacitors and resistors are made of copper-plated
steel; most connectors---even "gold-plated' ones--have a highly magnetic
nickel underplate; and many transistors pass current through their steel outer
cases. The possibilities for residual magnetism here are obvious, but how can
a pure copper wire, like those in a cable or the windings of a phono cartridge
become magnetized?
The fact is that copper is NEVER 100% pure. It ALWAYS contains impuri-
ties, among the more common of which are the metals of the iron triad.
These ferrous metals do not alloy with their copper matrix, but instead
remain in relatively pure concentrations at the junctures between copper
crystals, where, when current flow is present, they can easily become magne-
ti?~4 rn inr~rf~r~ ~ith rh~ cnllnd nf vnllr cvcrPm
This track is a specially recorded multiple 40 Hz to 19 kHz rising frequen-
cy sweep at constant amplitude. Playing it sends a signal through your entire
audio System, from CD player to speakers, that will, after just one or two
playings, randomize spurious residual magnetism and restore your system to
peak performance for days to come. As included on this disc, the demagne-
tizing signal is compatible both with regular two channel stereo and with
DolbyTM Pro LogicTM and other surroundsound systems. If used in stereo, it
will demagnetize both the RIGHT and LEFT channels at the same time. And,
if used in the surroundsound mode, it will demagnetize all channels at once.
Either in stereo or surroundsound, the demagnetizing signal is safe for you,
your pets and your system AT NORMAL LISTENING LEVELS. Remember,
though, that continuous high-volume high frequency signals can damage
tweeters, even if your ears don't perceive them as being too loud. The demag-
netizing sweep should sound clean, with no audible "buzzing" or "breakup",
which could indicate either natural room or speaker resonances or excessive
volume. If you suspect it may be too loud, turn the volume down! A good
idea with most speakers is to regularly check the tightness of all driver and
enclosure mounting screws and fittings. The normal vibration of the drivers in
operation CAN loosen them, and restoring their proper tightness can mate-
rially improve the sound of your System. {NOTE: DON'T OVERTIGHTEN!
Screws and mountings CAN be stripped if you're not careful!)
This track (but NOTTrack 8) may, with suitable precautions, be used for
demagnetizing most moving coil or moving magnet phono cartridges, and can
result in clearly audible improvements in sound quality. Be sure, however, to
CONSULT WiTH YOUR CARTRIDGES MANUFACTURER OR IMPORTER
BEFORE USINGTHISTRACK FOR DEMAGNETIZATION.
For most cartridges, simple current-limiting adaptors will provide adequate
protection against excessive current flow. An adaptor (one for each channel)
can be easily made by soldering a 2 kOhrn resistor between the center
(POSITIVE) contacts of a male and a female RCA connector as shown in the
accompanying diagram. Insulate the resistor leads with appropriate tape or
tubing to avoid "shorting" to ground, then solder an insulated wire between
the GROUND contacts of the two connectors. The parts for these adaptors
are available for just a few dollars from any electronics supply store. Any kind
of 1/4 or 1/2 watt resistor may be used, and tolerances are not critical.
PHONO DEMAGNETIZING ADAPTOR
(Use one per channel)
To demagnetize your cartridge, plug the adaptors into the Main or Tape
outputs of your preamp or receiver, then plug your phono cables into the
adaptors. Adjust the volume to a normal listening level, and PLAY ONLY
THIS TRACK. This will demagnetize both your cartridge and your phono
cable at the same time. IMPORTANT: if you use a moving coil step-up trans-
former, REMOVE IT FROM THE SYSTEM BEFORE DEMAGNETIZING.
Leaving the transformer in the circuit could damage both your cartridge and
the transformer. After you have completed the demagnetizing process,
remove the adaptors and restore your normal phono connections.
A one-second warning tone announces the end of Track 7. When demag-
netizing your cartridge, STOPYOUR CD PLAYER IMMEDIATELY UPON
HEARING THIS TONE, then repeat Track 7 as necessary.
Track 8 Low Frequency Demagnetizing Fade
WARNING: DO NOT USETHISTRACK FOR CARTRIDGE
DEMAGNETIZATION. SEVERE CARTRIDGE DAMAGE MAY
RESULT!
Because their crossover networks block out upper frequencies, the Iow
frequency power amplifiers and bass speakers of bi- or tri-amplified
Systems and the woofers of conventional loudspeaker systems will not gain
the full benefit of the demagnetizing sweep in TRACK 7. TRACK 8 con-
tains a specially recorded multiple declining amplitude fixed frequency tone
intended specifically to demagnetize Iow frequency components. Just play it a
few times through your System (either in stereo or DolbyTM Pro LogicTM or
other surroundsound) at normal listening volume. It will help "clean up" bass
performance, and can do no damage to the rest of your System.
Track 9 Burn-inTones
WARNING: NOT FOR PHONO CARTRIDGES.
EVERYTHING INYOUR SYSTEM NEEDSTO BE "BURNED-IN". Amplifiers,
preamps, tuners, CD players, and other electronic devices all sound better
after several hours to several days of continuous playing than they do "fresh
out of the box". Loudspeakers need electrical burn-in for the passive elec-
tronic components in their crossovers AND mechanical break-in for their
drivers. Cables, both interconnects and speaker cables, need burn-in to "form"
the dielectrics of their insulation and to bring them up to peak performance.
This surroundsound-compatible track is carefully engineered to provide
maximum burn-in effectiveness (both electronic and mechanical) for all of the
components of your System (EXCEPT PHONO CARTRIDGES, which require
MECHANICAL break-in ONLY).To use it, set the TRACK REPEAT or LOOP-
ING control on your CD player for continuous play, and allow the track to
repeat for the component or cable manufacturer's recommended time. If your
CD player has no "track repeat" or "looping" functions, set it on regular
REPEAT for a longer period of time. REPEATINGTHIS ENTIRE CD CONTIN-
UOUSLY FOR THE FULL BURN-IN PERIOD CAN DO NO HARM TO ANY
COMPONENT. IT WILL JUST TAKE LONGER FOR COMPLETE BURN-IN.
Burn-in of most electronic devices can be accomplished with everything
AFTERTHEM in the playback chain turned off (e.g. if you wish to burn-in
your CD player and the cable that runs from it to your preamp or receiver,
but NOT the preamp or receiver itself, the preamp or receiver can be turned
off. without affecting the burn-in process).This will avoid your having to listen
to the burn-in signal while it works.
For maximum benefit, preamps or receivers should be burned-in on each
LINE-LEVEL input (CD, tape, tuner, AUX, etc., but NOT phono) separately.
Because of the high additional level of gain always present, this Track must
NOT be used for burning-in PHONO inputs.
Power amplifiers (or the amplifier section of a receiver) must be ON and
playing at normal levels while burning-in, but to avoid having to listen to the
burn-in tones, you may temporarily replace your loudspeakers with 8 Ohm
ceramic power resistors of at least a 10-watt rating. These are available for a
very modest price at any electronics supply store. The best place to connect
these resistors (one per channel) is at the loudspeaker end of your speaker
cables. After turning the power amplifier or receiver OFF, and being very
careful NOT to touch the two leads of the speaker cable together directly,
disconnect the speakers and run the resistors from the POSITIVE lead to the
NEGATIVE lead of each cable, so that the body of the resistor separates the
two leads. No soldering or special connection is required~just wrap the
bare lead from the resistor around the spade lug or other connector at the
end of the speaker lead tightly enough to make electrical contact. Turn the
amplifier back ON for use. Placing the resistors this way will burn-in the
speaker cable at the same time as the amplifier, and will avoid accidentally
"shorting" the amplifier while trying to attach the resistors directly across
the amplifier output terminals. DO NOT BURN-IN YOUR AMPLIFIER AT
GREATERTHAN A NORMALVOLUME LEVEL. Resistors convert electrical
energy to heat and, in this instance, can be used as a test for excessive
amplifier volume. Check them after a few minutes of burn-in operation. If
they feel more than slightly warm to the touch, your volume setting is too
high, and should be turned down.
Most loudspeakers require SUBSTANTIAL burn-in time (as much as 200
hours) before achieving full performance. THERE IS NOWAYTHATTHIS
CAN BE DONE SILENTLY, but burn-in noise levels CAN be reduced consid-
erably by doing the following:, place the two loudspeaker systems face-to-face,
as close together as possible (touching is good), with the leads to ONE
speaker wired OUT OF PHASE (RED to BLACK/BLACK to RED).Throw a
blanket or other sound deadening material over both speakers, and play this
track CONTINUOUSLY at slightly below your normal volume control setting
for the manufacturer's recommended burn-in period. The out-of-phase wiring
will cause the sound from the two speakers to (more or less) cancel, and the
blanket will help to smother much of the remaining sound.
MUSIC TRACKS
NOTE: Monophonic test tracks should be used in two-channel stereo ONLY.
In surroundsound mode, the steering logic will route all mono signals (both
channels containing identical information) to the CENTER channel only,
bypassing the LEFT and RIGHT channels completely.
Track 10 MONO, in Phase
Here's a test that the "experts" have had all to themselves for at least the
last 30 years: a monophonic recording! In mono, both channels carry exactly
the same information, at exactly the same level, in exactly the same "phase",
so spatial information, which relies on differences in phase and amplitude
between the two channels, is ENTIRELY LACKING.
Playing a mono recording through a stereo System should result in all of
the sound appearing to come from a single point, exactly midway between
the two speakers. The general rule is,"The smaller the point the better." A big
"blob" of sound, or instruments moving around, or appearing to come from
different locations indicates that either the frequency response of the two
speakers is not identical, the acoustics of the room locations of the two
speakers are not identical, or there are anomalies in the speakers' dispersion
patterns.
An interesting effect (and a great quick test of the imaging ability of a pair
of speakers) is that, in general, the smaller the point to which a pair of speak-
ers will "image" in mono, the better they will image in stereo. Try this the
next time you're out shopping for speakers.
Track I I MONO, Out of Relative Phase
This track is actually recorded in "double mono",with a full monaural signal
(both left and right channel program material) recorded IN absolute phase on
the LEFT channel, and OUT OF absolute phase on the RIGHT. Because the
two channels are therefore out of phase WITH EACH OTHER, the two
channels are said to be out of"relative' phase. Use this Track just as you
would Track 3, as an aid in speaker placement and "dialing-in' room acoustics.
Track 12 STEREO, Out of Absolute Phase
It is possible for the two channels of your stereo System to be in phase with
each other (correct relative phase) but still out of phase with the original
sound at the recording venue (out of"absolute" phase). Ideally a positive
pressure at the recording microphone will ultimately result in a positive pres-
sure (forward movement) at the playback Ioudspeaken A polarity reversal,
though, (positive for negative, or negative for positive) at any point in the
recording/playback chain can reverse this with more or less audible results.
Unlike sine waves, which alternate equal (symmetrical) positive and negative
energy components, music signals tend to be asymmetrical, with waveforms of
unequal positive and negative energy. Many people (but NOT all) can hear a
difference if the polarity of these waveforms is reversed~if, in short, they are
out of absolute phase.
Listen to this track carefully, and compare what you hear to the sound of
Track 13. Can you hear a difference? (Remember that not everybody can.) If you
do hear a difference, does this track sound better than Track 13? Or worse? If
it sounds worse, be glad. Your whole System, from CD player to speakers, is in
correct absolute phase! If it sounds better, one of your components may be
phase-inverting. Check your Owner's Manuals to find out. (It's not common, but
it's not all that uncommon, either.) If one of your components does invert
phase, the simplest cure is to reverse the polarity of BOTH your speaker
cables (positive to negative and negative to positive) at EITHER the amplifier
or the speaker end, but NOT both ends. If it's NOT one of your compo-
nents, check your speaker cables to see if they've accidentally been reversed
Track 13 STEREO, absolute phase correct.
"StormyWeather" complete performance (6:40)
Harold Arlen/Ted I(oehler [Mills Music Inc./ASCAP]
EILEEN FARRELL (vocal), with Loonis McGIohon (piano), Joe Wilder (flugelhorn),
Bill Stow (drums),Terry Peoples (electric bass), Greg Hyslop (guitar), Phil Thompson
(saxophone). [From Eileen Farrell Sings Torch Songs, RR-34.]
This is a studio recording, with individual stereo microphones for each instru-
ment. Ambience is riot"natural hall sound;' but was generated with a com-
plex time-delay/phase program devised by "Prof." Johnson for the Lexicon
digital reverb generator. The overall effect should recall an empty nightclub:
it is late, the audience has left, and the musicians do one more number, just
for themselves, and for you. Farrell's voice should sound warm, natural and
up-front, with the instruments grouped nearby. Joe Wilder's flugelhorn solo
should sound farther back, beyond the drums, with more "room sound"
around it. [Consider that, when this recording was made, Eileen Farrell, one
of America's greatest opera singers, had just celebrated her 70th birthday.
RR was fortunate enough to make a total of seven albums with hen]
Track 14 "Shiny Stockings" (5:23)
Frank Foster [Lynnstorrn Publishing Co.]
Bob Lark / DePaul University Jazz Ensemble I
with Michael Stryker (piano) and Brian Culbertson (trombone)
[from B/g Band Basie, featuring ClarkTerry and FrankWess, RR-63]
From a simple piano solo at the beginning, this chart builds and builds to a
tremendous climax featuring five trumpets, three trombones, five saxophones,
acoustic bass and drums. If your system can reproduce this track at full vol-
ume without distortion, it will give you some idea of the power and dynamic
range of a classic big band heard live. Recorded in the Concert Hall on the
campus of DePaul University in Chicago, this "big space" presentation is quite
different from typical multi-mike studio jazz recordings.
Track 15 Morton Gould: Derivations for Clarinet and Band,
"Rag" movement (2:19)
[G&C Music Corp./Chappell & Co., Inc.]
John BruceYeh (clarinet) / Bob Lark / DePaul University Jazz Ensemble I
[from Ebony Concerto, RR-55]
Morton Gould is good at straddling musical fences. Although his greatest
commercial success came from pop orchestrations, he wrote many serious
scores. Deriva~ons, composed for Benny Goodman in 1955, requires a tradi-
tional big band jazz group to play written-out "classical" music. The brief
"Rag" movement is delicious in its transparent scoring, with solo passages for
many wind instruments. Recorded in the ideal acoustics of Medinah Temple,
Chicago, this is one of"Prof" Johnson's most highly-praised efforts.
Track 16 Jan~cek:Sinfonietta,"The Queen's Monastery" (5:01)
[Universal Edition] F~
Jose Serebrier / Czech State Philharmonic
from RR-65, with Jan~cek Taras Bulba and Lachian Dances
The first symphonic recording in HDCD, made in Stadion Hall in Brno, the
Czech Republic, this Jan~cek 5infonietta is something special. The sound of a
large body of string instruments has always been a great challenge for any
recording system, digital in particular. We feel that, at last, a digital master has
come close to capturing the silky, shimmering sound of twenty-six violins
(plus an equal number of lower strings) playing together. This movement also
features brilliant solos by many wind and brass instruments. (Don't miss the
extraordinary French horn "yelps" at 3:45.)
Track 17 Biebl:AveMaria (5:55)
[Hinshaw Music, Inc.]
The Turtle Creek Chorale /Timothy Seelig
from TheTimes of Day, RR-67, including DieTageszeiten by Richard Strauss
A wrap-around presentation of antiphonal choruses: a group of 30 voices
focussed front and center, with a larger group of nearly 200 voices to the
sides, and for those with surround sound, behind the listening position. Even
in standard two-channel stereo, the soundstage should extend well beyond
the speaker boundaries, to both sides of the listenen Recorded in the
Meyerson Symphony Center, Dallas, with its infinitely-adiustable acoustics set
for "cathedral."
Track 18 Weinberger:"Polka and Fugue" [~
from Schwanda the Bagpiper (7:49)
[Associated Music Publishers]
Frederick Fennell / Dallas Wind Symphony / Paul Riedo, organ
from Pomp & Pipesf, RR-58
A combination "Young Person's Guide to the SymphonicWind Band" and
sound-system-buster! After the lively and tuneful Polka, the Fugue (Index,
2:18) presents all the instruments in turn, so that their placements in the
soundfielcl can be clearly identified. At the entry of the pipe organ (5:38), the
music begins to build to a tremendous climax, which will challenge even the
most powerful sound system to reproduce cleanly. The strength and the
depth of the organ pedals and bass drum "whacks" will stress most home
playback systems into distortion, and at unwise volume levels, may blow fuses.
Play this passage first at moderate volume, until you determine how far you
can safely go. Good luck, and good listening!
XLO Electric is a young company that has
very rapidly come to the forefront of its field.
Since 1991, when the company was founded. XLO's products have
gained enthusiastic acceptance by audiophiles around the world and
have been the subject of an ongoing series of rave reviews in the
world audio press. XLO Electric Company has been nominated for
DuPont's prestigious Plunkett Award for Technical Excellence and the
"Golden Note Award" of the Academy for the Advancement of High
End Audio (AAHEA).
XLO Electric was started by Roger Skoff, who, like a number of
other High-End luminaries (Conrad and Johnson, for example), is an
economist by training. He was educated at UCLA, has been Director
of Business Analysis for four divisions of International Industries, Inc.,
and has consulted to various companies, including a number listed on
the Fortune 500.
Since the age of twelve Mr. Skoff has had an active and growing
interest in sound and its transmission and reproduction. Besides a
life-long commitment to the very finest in High Fidelity sound, he
has, in addition to his regular professional career, worked as a
recording engineer, a radio announcer, an audio equipment reviewer
for Sounds Like... magazine, and as Editor of Sounds Like...News.
Mr. Skoff's active involvement in the design of high-performance
audio cables began as a recreational math exercise in late 1986. This
rapidly passed from a purely abstract theoretical study to the stage
of concrete experimentation, and by 1988 the first of his cable
designs; now known as XLO ElectricTM Type I, was completed.
Other designs followed, and by the time he started reviewing, most
of the cables now comprising the XLO Electric Reference Series had
been built and were incorporated into his Reference System for eval-
uating the performance of other High-End audio components.
Because of the strict ethical requirements of reviewing, however, and
because Mr. Skoff had no intention whatsoever of offering his cables
for sale, the cables were identified in his system only with a mislead-
ing "codename"; they were never written about, and their source was
kept a strict secret, even to most other reviewers.
Some reviewers though, close friends of Mn Skoff, not only knew
the cables' source, but were even given some for use in their own
reference systems. From this use, the word
spread that a new "mystery cable" -- of
unknown origin, and not available at any
price -- was on the scene, and it quickly
became the talk of audiophiles across the
United States.
When the truth finally leaked out, in
November of 1~90, at a meeting of the Audiophile Society in
Westchester County, NewYork, Mr. Skoff received, within just a few
weeks, nearly a hundred phone calls from enthusiastic audiophiles
wanting to buy his cables.
The rest is history: in December, 1990, he took a leave-of-absence
from the magazine, to prepare sample cables for trial introduction at
the Winter Consumer Electronics Show of January, 1991 .The
response at the Show was immediate and overwhelming: dealers in
the United States and Distributors abroad WANTED the cables. The
result was that Mr. Skoff's departure from the editorial field became
permanent and in March of 1991, XLO Electric Co., Inc. was formed.
Reference Recordings
has earned the international reputation for
producing recordings to the very highest
musical and technical standards.
RR's artists are widely known and respected in their various fields,
and the label takes special pride in presenting a wide variety of musi-
cal sty[es: classical, jazz and cabaret.
Engineering is most unusual."Prof." Keith Johnson is one of audio's
most creative men, having designed and patented many innovative
products in the professional and consumer fields. "Prof." Johnson
engineers all RR releases, using unique equipment designed and built
(or extensively modified) by himself. Microphone techniques range
from "purist" single-point Blumlein to spaced omnis to complex studio
mixes, depending on the musical forces and the performing space
involved.
RR is the recipient of many industry awards, including a Grammy~
(and three nominations), a NAIRD "lndie' award, and two "Golden
Note" (AAHEA) awards for Best Recording. RR is also a pioneer in
1996 marks the 20th year of RR's innovative
)rogramming and engineering.
For a free, complete RR catalogue,
call 800-336-8866, fax 415-355-1949,
EMail rrec~aol.com, or write to
Box 77225X, San Francisco CA 94107 U.S.A.
The revolutionary High
Definition Compatible Digital~
process, co-invented by "Prof." Keith Johnson
and Michael HUaumer in association with Vacitic rqicrosonics, Inc., is
destined to make all notions about the sonic inferiority of digital
recording obsolete.
Seven years in development, HDCD is taking the professional
recording world by storm. Audio engineers and industry professionals
worldwide have been awestruck by the definition, clarity and natural
"warmth" of sound which the HDCD process gives to digital record-
ings and playback.
HDCD recordings can be played by any compact disc player, and
many of the sonic benefits of the process can be heard without
decoding. However, to extract all the extra information the process
encodes onto CDs, a player with an HDCD decoding chip is neces-
sary. Note that players which incorporate the HDCD chip demon-
strate much improved sonics playing standard compact discs. HDCD-
decoding players are now widely available from many manufacturers.
"With HDCD, the promise of the compact disc
cakes a giant step toward fulfillment"
--Lawrence B. Johnson, The New York Times
Producers: Roger Skoff and J.Tamblyn Henderson,Jr.
Recording Engineer: Keith O. Johnson
Executive Producers: Marcia Gordon Martin, RS, JTH
CD Mastering: Paul Stubblebine, RS, JTH at Rocket Lab, San Francisco
Oesign: Robert Ross Associates,Therese McGIone,JTH
