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In Reply to: RE: If your... posted by AbeCollins on September 12, 2014 at 15:49:27
"Is it not true that most of what we consumers listen to came off master tapes? Is it also not true that these tapes have a dynamic range of about 70 or maybe 80dB at best? I would also assume that this is under ideal conditions that are rarely met."
Most consumers listen to MP3s or equivalent. These people and their tastes in music and listening are not relevant to audiophile forums.
If high resolution digital formats (24 bit PCM or DSD) are used the recoding medium and converters will have no problem achieving 120 dB dynamic range. The weakest link is going to be the microphone and microphone preamplifier which are limited by random motion of air molecules and Johnson noise. State of the Art microphones used to record classical music have a dynamic range of approximately 120 dB. The best recording labels use minimal post production, so one hears the first generation output of the microphones. (Example are the Channel Classics recordings, most of which are pure DSD with no post processing.)
"At 120dB down aren't we also well into the noise floor of most audio systems?
Not good ones.
Tony Lauck
"Diversity is the law of nature; no two entities in this universe are uniform." - P.R. Sarkar
Follow Ups:
"If high resolution digital formats (24 bit PCM or DSD) are used the recoding medium and converters will have no problem achieving 120 dB dynamic range."
I know that most consumers today probably listen to MP3. When I said 'consumers' I was talking about the medium from which recording engineers and such work from before the final product is sold and delivered to the consumer.
Assuming the working medium is a master tape, are you saying we will still be able to achieve 120dB dynamic range to and from the tape? If memory serves me, I thought high-end pro tape machines and their tapes are limited to less than 80dB.
The best medium from which the best recording engineers presently work today is a live microphone feed. This is captured directly by the ADC and distributed unchanged (except for "razor blade" editing) directly to the consumers. This is how Channel Classics works and why their sound quality is better than any other classical music label issuing recordings today. They also happen to use the best available DSD ADC.
There are first rate engineers working with tape at high speeds and width, presumably because they like the slight dynamic compression tape provides. This is suitable for some styles of recording and some musical genres. This is what Blue Coast Records does. They then mix the tape down to DSD and other digital formats.
With the arrival of state of the art DSD converters such as the Horus that work up to DSD256, expect to see other production processes come into play. At present, recording directly to DSD has not been practical for musical genres that depend on heavy post production, because of the generation loss converting in and out of DSD64. (This is apparent in a few of the Channel Classics tracks I have that are not pure DSD because post production was necessary for artistic reasons. I have both the original and remixed files of one of these tracks and can hear the sonic degradation from the DSD - DXD - DSD processing.)
Tony Lauck
"Diversity is the law of nature; no two entities in this universe are uniform." - P.R. Sarkar
Thanks Tony, I understand what you're saying about direct from mic to high resolution digital recording but here's what I'm wondering about:
If the masters reside on tape as many albums do, and tape has a dynamic range of no more than say 70 to 80dB at best, and that tape is used to create 'high-res' digital files, what is the benefit of a DAC with 100dB+ dynamic range if the source material's range is significantly less?
"If the masters reside on tape as many albums do, and tape has a dynamic range of no more than say 70 to 80dB at best, and that tape is used to create 'high-res' digital files, what is the benefit of a DAC with 100dB+ dynamic range if the source material's range is significantly less?"
If the dynamic range of the DAC is limited by purely additive noise and the additive noise has the same spectrum as the tape noise, then, given that the tape noise was 20 dB louder, there would probably be no benefit to a DAC with such dynamic range, provided that the digital transfer used all of the available dynamic range of the digital media (give or take a few dB) and provided that no digital volume control was used. If one of these provisos does not apply then more dynamic range in the DAC would probably make a difference.
Personally, I could care less about purely additive white noise, so long as it is at a low enough level. The problem is that the DNR of the DAC may be limited for reasons other than additive analog noise. Even something as simple as TPDF dither does not result in purely additive noise, despite the lies Redbook apologists tell. So if the noise comes from any portion of the digital processing, then the music is likely to be distorted unless the designer really understands digital signal processing.
Perhaps the most significant reason for a low DNR in a DAC is that it can only be achieved with paranoid attention to detail on the part of the designer. However, if there are design reasons for the noise that have other benefits at the expense of benign noise, then such a DAC may be preferable, even though it measures poorly on DNR. Some DACs push their analog electronics to measure good and this leads to an unnecessarily harsh sound (even digital clipping) on loud portions of recordings. This is just one of many reasons to be distrustful of products that are designed to measure good, rather than sound good.
Tony Lauck
"Diversity is the law of nature; no two entities in this universe are uniform." - P.R. Sarkar
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