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Didital Things
Topic: The optimum Sampling Rate for bass.

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Posted by Romy the Cat on 02-19-2008

Since I do not do SACD and stay in PCM world I always wonder what the optimum sampling rate might be.  As I told I discard the 48X as never was necessary rate. So, we have 44.1K, 88.2K, 176K and 352K… Surely we are out of 16-bit world – a move from 16bit to 20 or 24 bit is the largest step-up in any PCM improvement. I have to admit that I recorded 16/44 and as long the file never was re-render by DSP and never was converted to CD the quality of Sound was very high for “red book” – none of CDs come even close. The recording in true 20 bit and 44K already set all bets off and delivers very reputed result. From there we can settle at 24bit  (though I hear no difference between 20 and 24 bit) and only were we can go from here is to increase the sampling rate - 2X, 4X, 8X…

In context of it I think it would be interesting to look at Dan Lavry position on the subject. He believes that optimum rate is in 60-70KHz as going faster reduces accuracy and therefore he considers the damming for higher rate is a pure marketing force demand. He have written a number of position paper on the subject if someone interested then is very education read – they are publicly available. Particularly I was very fascinated with Lavry’s explanation how higher sampling rate destroys bass.

What is very captivating in this subject is that very same take place with analog – a higher tape speed improves everything but kills bass quality. The 7½ ips has properly structured bass. At 15ips the total sound is incontestably better but bass become “too fast”. The 30ips delivers the identical with the source sound with good bass but it is “different bass”. I initially thought that the bass problem at high speed are related to the moderation of pressure of tape to the machine heads but playing with it ( and in my past I did it a lot, appalling tremendous pressure to the tape heads) I more feel that the lower tape sapped might be beneficial for bass by nature.

I do not have an answer and I always wonder if the relation between speed and bass is the subject of pure implementation or there are some fundamental advancement of lower speed (tape or sampling rate) for better bass.

The caT

Posted by Romy the Cat on 09-27-2009
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I got one of those Reference Recordings 176KHz files to try.  Everyone so go rave about them…

I did not truly pursuit them before as whatever they have interesting musically was released before – how much you can listen the same 5 disks even if they this time released in better format?

Anyhow, I was wondering about the 176/192kHz. The Pacific can play them - why the hell do not try?

So, I did it… and I am not impressed. The upper region instruments are very nice but the lower region sounds all have wrong formants. I got more 176kHz recordings and all of them had not the same but similar effect – the bass is just wrong. Even more: because the bass is kind of “strange” those glorious HF notes do not really connect with anything and they juts sound as stand-alone notes. I find it musical.

I wonder, the Morons out there are choking in orgasmatic screams about the 176/192kHz, why I cannot concur it? I see a few possibilities:

1)      I am an idiot why has no idea how it shall sound (I degree with it as I do not see evidences of it.)

2)      The files that are pitched to us as Master Files had already barbarously edited and all bass was destroyed (highly possible)

3)      My 176/192kHz Pacific DAC is not good. (Possible, but most if not all of those files were recorded on this processor. The Pacific in 44/88 is good, why would it be worse in 176/192kHz?)

4)      The high-resolution digital very much like the high-speed reel tape does benefit HF for the expense of LF  (possible,  there is a group of world-class sine who support this view but I do not treat their view as a definitive)

5)      The 176/192kHz is too fast and the Morons who adore it are juts Morons. (Possible, the LF formants on 192kHz sound very similar to the contemporary pressings LP. The idiots like them but there is a reason why I call then idiots)

I think I would need to record the same thing in 88kHz and 176kHz and to compare.  I have only one Pacific processor that can do it – so, the result might be too much Pacific-centric. I do not know. I have no judgment on the subject. It is kind of strange - I am trying to find out if 176kHz it “better” then 88kHz but at the same time my absolute reference in sound quality is BSO from 1949….

The Cat

Posted by manisandher on 09-27-2009
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Romy,

I've wanted to do this comparison for a while now. Apart from just not having the time recently, the biggest obstacle has been not being able to use the Pacific in Master mode above 96KHz. As you know, it will only output a clock at 1x/2x 44.1KHz or 48KHz. The Weiss AFI1 cannot double this clock frequency. I've been on to Daniel Weiss about this, but he hasn't come back to me with a solution as yet.

Will your Lynx card allow you to use the Pacific in Master mode at 176.4/192 rates?

Mani.


Posted by Romy the Cat on 09-27-2009
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 manisandher wrote:

I've wanted to do this comparison for a while now. Apart from just not having the time recently, the biggest obstacle has been not being able to use the Pacific in Master mode above 96KHz. As you know, it will only output a clock at 1x/2x 44.1KHz or 48KHz. The Weiss AFI1 cannot double this clock frequency. I've been on to Daniel Weiss about this, but he hasn't come back to me with a solution as yet.

Yes, Pacific does not double clock in 2-wire configuration. I would certainly not use any clock frequency doubles as it would create more problems then help. The Pasific’s David proposed to use a half clock as reference, it is what I do. I have found another, even bigger problem in Pacific; I will post it in your Pacific thread.
 manisandher wrote:
Will your Lynx card allow you to use the Pacific in Master mode at 176.4/192 rates?
Yes, the Lynx can handle up to 200.000Khz
 
The Cat

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