这小东西大家聊 [复制链接]

JWang 在 2006-6-3 7:06:13 发表的内容
在我关于LP的高频测试的贴子中，felixcat一看到是我写的，就迫不急待跳出来，大讲半速刻制什么什么。实际上他跟本不懂什么叫半速刻制。他多次被我指出他的错误百出之处。故每次我的贴，他总要胡搅蛮缠一气，结果总是搬起石头砸自己的脚。看看前面他关于频响曲线的讲法，连基本常识都没了。好，现在他改变战术，还要在那个屁股后面跟一个贴，讲明不答，不应在我的ID下的贴。呵呵，认输了还是什么？够蠢的。

英语中有句话，If you can’t stand heat, get out of the kitchen！用中文来讲，如果你不能忍受热量，滚出厨房！网上也一样，只要我开口，我不怕任何人来加以批评。我也不怕任何没头没脑的人的骂街。相反地，我从不会邀请felixcat来评论，但felixcat只要有这个胆量来针对我来讲，我必答无疑。你如果受不了，你可以闭嘴不讲。尽管你的知识面很狭窄，分析问题的能力又很差，但不用人家来教你如何闭上嘴吧！

下面是半速刻制的创始人Stan Ricker讲半速刻制的LP可以在音质上超越母带。我没有功夫把全部翻成中文，而是挑些关键字句翻。这是enjoymusic.com对Stan Ricker的一个采访。补充一句，引用Stan Ricker的讲法并不代表我的观点。只是给大家一个参考。

Dave:    You've told me that some of the things that you like about the sound of half speed is that it has lower distortion and better transient response and improved high end, and that one of the big benefits is that when you drop the frequency band by an octave it requires only one fourth the amplifier power to cut the record.
  
Stan:    Yeah.  You drop it by an octave and you also double the length of time it takes to put the signal on the record.  So you've got the two factors of two there.
  
Dave:    So how is it possible for a lacquer, which is cut at half speed, to sound better than the master tape from which it was made? （如何可能一片从母带制成的黑胶比母带声音更好？） At first blush that sounds like a bit of a conundrum, but I understand that it is really not.
  
Stan:    Quite a condom, you say?  (Laughs)  You've got to realize that it sounds better played at real time than the analog tape does, played at real time.  One of the primary reasons for doing the half speed analog recording is that more tape playback problems are solved by playing the tape back at half speed.  （其主要的原因之一是母带在以半速播放时可以克服母带在全速播放时的很多毛病）Hysteresis problems in the playback head, the slew rate problems in the tape head preamplifier; the resonance peak of the playback head circuitry is a fixed resonant peak, so in terms of the music you're transcribing, it's moved up an octave and is way out of the audible range of any of those high frequency resonance circuits.  So when you consider all of this, therefore, the signal is cleaner as it passes through the system, especially anything that involves cymbal crashes, brass instruments [trumpets, trombones, etc.] other high frequency type tone bursts.  At half speed they go through the system quite easily and are not apt to cause any kind of power supply or slew rate distortion, or TIM, or any of this stuff.  So if you can cut a disk that way and you have a really pristine disk playback system like many audiophile folks do, then you get to enjoy the advantage of a record that was cut from a tape in a way that you get away from a lot of these tape playback anomalies.  The tape record and playback anomalies are part of why Doug Sax did all those marvelous direct-to-disk sessions.  （Dong Sax的那些直刻盘其部分原因就是因为录音带及重放中的毛病）The tape machine itself is a huge stumbling block in the transparency of the audio, of the music, of the sound.  The transient response isn't there and with tape, as with practically every recording medium, it's easy to get the signal recorded; it's harder to recover it.  So, if you recover it at half speed, transfer onto another medium, and you have a really good playback of that other medium, the phonograph record, then when you compare the analog tape played at real time versus the lacquer played at real time, the signal off of the lacquer has managed to come out without all the problems inherent in real-time tape playback.  So what you're really hearing is the signal with problems and then the signal without the problems.  That, to me, is why half speed mastering was such a phenomenal process.  I used to think that this was because of the lower amount of power required at half speed.  But I'm convinced now that it's about a 70/30 situation.  That seventy percent of the improvement is due to scanning the tape at reduced velocity, and not driving those tape head preamplifiers into gross distortion.  We just hear people say, "Oh yeah, that's just analog tape overloading, or whatever."  Whereas, in reality, we recover it without those problems.  That's why it's been such a tremendous treat to find some of the really good stuff buried on some of that old Scotch 111.  It really is quite possible that the disks, under those conditions, can sound better than the master tape played at real time.  It's amazing to listen to a good analog tape at half speed, one that's truly wide range, low distortion.  I mean, it just blooms in front of you.  It's just unbelievable.  I think of the experience I had listening to a MoFi re-release recording of Russian music, with the Russlan and Ludmilla Overture in D Major [MFSL 1-517].  I mean it's full orchestra, the orchestra's just going a mile a minute, just lickety split.  At half speed the recorded sound just opens up and wow!  And it was not a Dolby tape, and that was important.  It was pre-Dolby for Decca.  Just such a wide open spaciousness.  When you played it at real time it tended to get congested.  But the record didn't come out that way.  The record has the spaciousness of the original tape, which you could only really perceive in the half speed mode.  There's a lot to be said for half speed transcription.  I tend to like, right now, this two thirds speed thing because the bass frequencies seem to be better integrated with the mid range and treble.  It didn't always happen at half speed.