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Topic: Vinyl vs Digital and 24 bit vs 16 bit from vinyl. (Read 204287 times) previous topic - next topic
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Vinyl vs Digital and 24 bit vs 16 bit from vinyl.

Reply #25
Oh, nice! Another flat transfer partisan. Welcome to the club.


I have to wonder, what does all that RIAA curve do to your overall gain structure and dynamic range, then.
-----
J. D. (jj) Johnston

Vinyl vs Digital and 24 bit vs 16 bit from vinyl.

Reply #26
The gain structure and DR are completely f*cked up, but the RIAA curve has nothing to do with that. It's entirely because the sound card I chose (an E-MU 0404 USB) appears to have an inferior dynamic range at 60db gain compared to its competitors. (I'm told that other integrated preamp/ADCs have no problem punching 80db SNR at that gain.)

Even then, the sound card noise floor is 10db lower than the noise floor of a quiet groove, at all frequencies. It still sounds pretty good.

Are you aware of Rob Robinson's AES preprint from the 123rd convention? ("Filter Reconstruction and Program Material Characteristics Mitigating Word Length Loss in Digital Signal Processing-Based Compensation Curves used for Playback of Analog Recordings").

Vinyl vs Digital and 24 bit vs 16 bit from vinyl.

Reply #27

Oh, nice! Another flat transfer partisan. Welcome to the club.


I have to wonder, what does all that RIAA curve do to your overall gain structure and dynamic range, then.



AFAIK, the filter does nothing more than what a hardware RIAA filter does since ...

- overal gain can be controlled by adjusting the gain coefficients (mine is set as no extra gain)
- I've never measured if there is something strange with the DR

... ABX between hardware RIAA and this method is not necessary here since the result is ~different (this depends on how good RIAA stage you have for your cartridge ... is it optimized by the cartridge specs, etc.)

... IMO, you need to hear the difference to tell which one is more natural sounding (I like the result I get a lot since low frequency area is much deeper/sharper (there's a sound there) and mid/high areas are clearer w/ lots of details I can't get out of the hardware path of my stereo system ... but as said, it's the hardware altogether involved in this)

These software filters I have programmed (by calculations mentioned in quote below) are just a bit more accurate in reproduction of the RIAA EQ (accuracy depends on selected sample rate ... I normally use 3th-4th order IIR filters so the maximum error @ 0Hz to 20kHz is calculated  between ~0.0006dB (44.1kHz - ~0.000004dB (96kHz) and the phase is OK.


Here's the procedure how these filters been calculated by Robert Orban:

Quote
>Robert Orban wrote:
>
>> I can't see the first part of this thread, but if you are trying
>> to do an IIR simulation of the RIAA phono de-emphasis curve
>> (assuming s-plane poles at 50.5 and 2122 Hz and an s-plane zero
>> at 5005. Hz), here are some good minimum-phase magnitude
>> approximations.
>
>Neat, thanks! How did you make them?

I used a program I wrote (in ye olde Fortran :-). The outline goes as
follows:

Given a desired magnitude response in the z-plane, there exists a
response in a frequency-warped u-plane that, when bilinear-transformed
to the z-plane, creates the desired z-plane magnitude response.

-Compute the [magnitude response]^2 of the s-plane prototype on a grid. 
This is the square of the desired z-plane response.

-Warp the frequency axis by using the bilinear transform, recognizing
that we are approximating using omega^2 as our frequency variable. The
warp maps Nyquist to infinity.

-Make a least-squares rational approximation (i.e., ratio of
polynomials) to the values on the frequency grid. (I used the Numerical
Recipes routine RATLSQ, which uses Chebychev polynomials.)

-Refine the approximation to make the fractional error minimax by using
Remez's Second Algorithm [which applies to rational functions; it's not
the same as the Remez algorithm used in the classical MPR FIR design
program; see Forman S. Acton, Numerical Methods That Work (Revised
Edition), Washington D.C., American Mathematical Society, 1990, pp 310-
314]

-Transform the result into the z-plane in two steps. The first
recognizes that we have been approximating using the magnitude square
function, so we must take the square roots of the poles and zeros of the
approximated rational function, taking the negative real parts to
guarantee a stable, minimum-phase function. The second step is to apply
the bilinear transform to the result of the first step. This yields the
final z-plane poles and zeros.

There are some "interesting" numerical issues in making this procedure
work, mainly because the Remez update formulas require solving a system
of mildly nonlinear equations that tend be ill-conditioned.

The nice thing about the algorithm is that the frequency-warping moves
Nyquist to infinity and thus increases the resolution of the
approximation close to Nyquist, which is where difficulties often occur.


Robert Orban

Vinyl vs Digital and 24 bit vs 16 bit from vinyl.

Reply #28
The Emu specs say the preamp noise is approaching the minimum possible, which is quite good at that price, even without consideration of the rest of the box's contents. You find that its noise is unusually high near full gain? Is this full spectrum noise? Do RMAA tests tell you anything interesting?

Vinyl vs Digital and 24 bit vs 16 bit from vinyl.

Reply #29
The gain structure and DR are completely f*cked up, but the RIAA curve has nothing to do with that. It's entirely because the sound card I chose (an E-MU 0404 USB) appears to have an inferior dynamic range at 60db gain compared to its competitors. (I'm told that other integrated preamp/ADCs have no problem punching 80db SNR at that gain.)

Even then, the sound card noise floor is 10db lower than the noise floor of a quiet groove, at all frequencies. It still sounds pretty good.



I'm using the same E-MU 0404 USB which don't necessarily need another pre-amp for input ... it gives good enough quality for playback purposes (in this case I gain the filter 15-20dB and the RIAA EQ is done realtime) but, I also have prepared matched pre-amp too for recording purpose mainly (I'm using Technics turntable w/ Technics 205CMK3 cartridges ... which is quite capable cartridge by the factory measures they include into bundle).

Juha

Vinyl vs Digital and 24 bit vs 16 bit from vinyl.

Reply #30
Are you using a moving coil cartridge? Normal gains for MM is around 35dB, if I remember correctly. Or is there some reason you need more gain with MM using that approach (quite a bit more gain!)?

Vinyl vs Digital and 24 bit vs 16 bit from vinyl.

Reply #31
Are you using a moving coil cartridge? Normal gains for MM is around 35dB, if I remember correctly. Or is there some reason you need more gain with MM using that approach (quite a bit more gain!)?



If this was for me then, I'm using MM cartridges.

Juha

Vinyl vs Digital and 24 bit vs 16 bit from vinyl.

Reply #32
No, Axon is the one turning the gain to maximum.

Vinyl vs Digital and 24 bit vs 16 bit from vinyl.

Reply #33
The gain structure and DR are completely f*cked up, but the RIAA curve has nothing to do with that. It's entirely because the sound card I chose (an E-MU 0404 USB) appears to have an inferior dynamic range at 60db gain compared to its competitors. (I'm told that other integrated preamp/ADCs have no problem punching 80db SNR at that gain.)

Even then, the sound card noise floor is 10db lower than the noise floor of a quiet groove, at all frequencies. It still sounds pretty good.

Are you aware of Rob Robinson's AES preprint from the 123rd convention? ("Filter Reconstruction and Program Material Characteristics Mitigating Word Length Loss in Digital Signal Processing-Based Compensation Curves used for Playback of Analog Recordings").


Yes, it's a simple exercise in filtering.

You don't see the 20dB in slope causing you any overload problems, etc. Oh, say, with Dark Side of the Moon? (JJ squints at a spectrum he just measured and wonders...)
-----
J. D. (jj) Johnston

Vinyl vs Digital and 24 bit vs 16 bit from vinyl.

Reply #34
It's entirely a matter of the gain used. I can clip if I actually set the gain to 65db and then play, say, the spot frequencies on STR151. (Note that this is a LOMC, an AT-OC9, I'm talking about.) But it's fine at 55db, I can always turn it down further if it overloads there, and I don't think I'll see many 20khz tones at those kinds of levels anyway... At 55db, normal classical LP levels hover at around 13-18db, and pops/ticks peak at -3. (Since I've never encountered that relatively high level of pop with my 440ML, I guess you could take that as some sort of empirical evidence for an MC having a tighter phase response than an MM. The transient when the stylus lands on the record is razor-sharp.)

I haven't recorded DSOTM yet (and well, my pressing is a well-work original Capitol, so it's not like it has much treble to begin with). But I did record Bernstein's Carmen, and while the opening cymbals are piercingly loud when recorded without RIAA, they are notably distortion-free. (It's worth noting that right now I'm recording at 24/44 and I'm using a naive bilinear IIR implementation of the RIAA filter, but once I actually implement the filter correctly, and perhaps record at 24/96, I'm not anticipating any surpises.)

It's also worth noting that the noise profile of both the sound card and the vinyl background hiss when flat-transferred (that I've measured so far) is white.

Vinyl vs Digital and 24 bit vs 16 bit from vinyl.

Reply #35

Are you using a moving coil cartridge? Normal gains for MM is around 35dB, if I remember correctly. Or is there some reason you need more gain with MM using that approach (quite a bit more gain!)?
If this was for me then, I'm using MM cartridges.

Yeah, like I said above, I'm running MC. The OC9 has a sensitivity of around 0.4mV IIRC. Obviously, if I was still running with my 440 it would all be running like gangbusters, but I was running into a lot of EM interference issues running balanced into the 0404, and going fully balanced on the 440ML requires physically cutting the ground tab that's hard wired to one of the signal wires, and I was really enamoured of the thought of not requiring any loading, just a straight shot to the XLR inputs... I'm having to rethink that now.

The Emu specs say the preamp noise is approaching the minimum possible, which is quite good at that price, even without consideration of the rest of the box's contents. You find that its noise is unusually high near full gain? Is this full spectrum noise? Do RMAA tests tell you anything interesting?
Creative Labs is full of shit. What else is new?

The 0404 USB's specs are awesome on paper, as are the RMAA results. The problem is that the EIN/SNR numbers, while accurate, only apply for 0db of gain applied. As soon as you apply gain, you lose that EIN/SNR. So while you do in fact have that 105+db SNR with no gain, at 65db, you're literally down to 60db.

That is not how it's supposed to work. The Focusrite Saffire has an EIN of 120db at 60db of gain. Rob has tested the Saffire and it runs like a champ wired up to a LOMC, with no noise issues.



BTW Juha, that's really good info on using Remez to optimize IIR filter design. I've been having a lot of trouble coming up with high-accuracy RIAA coefficients.

Of course, is it possible for you to just post the coefficients for 44/48/96/192khz?

Vinyl vs Digital and 24 bit vs 16 bit from vinyl.

Reply #36
BTW Juha, that's really good info on using Remez to optimize IIR filter design. I've been having a lot of trouble coming up with high-accuracy RIAA coefficients.

Of course, is it possible for you to just post the coefficients for 44/48/96/192khz?


http://www.dsprelated.com/showmessage/73300/3.php



EDIT:

BTW, which one would be the better place to put the (subsonic) HP Filter in signal path ... before or after RIAA Filter?

Juha

EDIT2:

BTW, Axon, would it be too much to ask from you if you mail me or link here a short sample (~0.5-1 min) of some of your flat recorded vinyls you feel is a good for testing this software RIAA filter in action. As I'm using VST based technology, I could render the sample w/ filter added and send it back (or link here) so you (or anyone) could make some comparisons too. Sample file bit-resolution could be any and the sample-rate 44.1/48/88.2 or 96kHz but, the format should be better to be lossless (FLAC, WAV).

Juha

Vinyl vs Digital and 24 bit vs 16 bit from vinyl.

Reply #37
Therefore digital is superior as a delivery format because it's doesn't impose its own character on the audio. "Special effects" should be added because people want to, not because they're part of the delivery format.
  Sure, but what if the music was originally an analogue recording? Are you suggesting it all should be digitally remastered? Personally, I'd try to preserve the original sound by not messing with it. By the way, imho, there's more than enough music for both analog and digital reproduction, just in case you were worried about missing out on something. 
Quis custodiet ipsos custodes?  ;~)

Vinyl vs Digital and 24 bit vs 16 bit from vinyl.

Reply #38

Therefore digital is superior as a delivery format because it's doesn't impose its own character on the audio. "Special effects" should be added because people want to, not because they're part of the delivery format.
  Sure, but what if the music was originally an analogue recording? Are you suggesting it all should be digitally remastered?
Well unless the studio is going to send me the original master tape and some equipment suitable for playing it back, then yes of course - put it on a CD, or 24/96 lossless FLAC or whatever.

Actually, even if they studio _is_ willing to send me the original master tape, I'd rather they didn't. I'd feel quite guilty wearing out all those Beatles master tapes just for my own private listening pleasure. Much better to make a digital copy that can be duplicated without loss as many times as necessary.


Of course I'm asking for a _good_ digital "remaster" - a careful transcription of the original - none of this dynamic range compression smashing against 0dB FS, and none of these terrible "drag a third generation dub off the shelf, play it on any old machine, ignore the EQ that was supposed to be applied at playback, and digitise it" efforts. But yes, digital every time. I even like noise reduction, and digital re-mixing to avoid a tape generation loss inerrant in an analogue master - though both are difficult to do in a way which pleases everyone, and good "modern" analogue mixing and mastering is already more than good enough.

People get very upset with the use of digital remastering to create vinyl. I mentioned the Beatles - many of their CDs and "remastered" LPs sound nothing like the original LPs, but "digital" isn't to blame - I can copy the original LPs onto CD just fine!

Cheers,
David.

Vinyl vs Digital and 24 bit vs 16 bit from vinyl.

Reply #39



BTW Juha, that's really good info on using Remez to optimize IIR filter design. I've been having a lot of trouble coming up with high-accuracy RIAA coefficients.

Of course, is it possible for you to just post the coefficients for 44/48/96/192khz?


http://www.dsprelated.com/showmessage/73300/3.php
WOOT! Thank you.


Quote
BTW, which one would be the better place to put the (subsonic) HP Filter in signal path ... before or after RIAA Filter?
Well, if it's in the software domain, does it really matter? As long as you're working in floating point, it shouldn't.


Quote
BTW, Axon, would it be too much to ask from you if you mail me or link here a short sample (~0.5-1 min) of some of your flat recorded vinyls you feel is a good for testing this software RIAA filter in action. As I'm using VST based technology, I could render the sample w/ filter added and send it back (or link here) so you (or anyone) could make some comparisons too. Sample file bit-resolution could be any and the sample-rate 44.1/48/88.2 or 96kHz but, the format should be better to be lossless (FLAC, WAV).
Yeah, I guess I could put something together. I'm out of web space at the moment, though (my old provider disappeared in the middle of the night - I'm not even kidding). I could probably email a small FLAC or send it through gmail?



Actually, even if they studio _is_ willing to send me the original master tape, I'd rather they didn't. I'd feel quite guilty wearing out all those Beatles master tapes just for my own private listening pleasure. Much better to make a digital copy that can be duplicated without loss as many times as necessary.
Heh, heh, heh.

Vinyl vs Digital and 24 bit vs 16 bit from vinyl.

Reply #40


Therefore digital is superior as a delivery format because it's doesn't impose its own character on the audio. "Special effects" should be added because people want to, not because they're part of the delivery format.
  Sure, but what if the music was originally an analogue recording? Are you suggesting it all should be digitally remastered?
Well unless the studio is going to send me the original master tape and some equipment suitable for playing it back, then yes of course - put it on a CD, or 24/96 lossless FLAC or whatever.
Actually, what works for me is simply playing the album on a good table. As well, I've had great success with prerecorded cassette tapes and a decent deck. Personally, I'm amazed at how how much great analog audio is still available and at very affordable prices.
Quis custodiet ipsos custodes?  ;~)

Vinyl vs Digital and 24 bit vs 16 bit from vinyl.

Reply #41
24-bit precision gives you about 16.77 million values. Assuming a total groove width of 50 x 10^-6m, the maximum movement of the cutter is physically bounded at about half that. Much more and the cutter will be in the space for an adjacent groove.  Thus, 50 microns width divided by 16.77 million gives us about 3 x 10^-12m, i.e. ~0.03 angstroms.

The diameter of a hydrogen atom is 1.0 angstroms (1 x 10^-10m). That would make the resolution of a 24-bit digital signal equivalent to an analog cutter whose resolution is just about 1/30 the width of a hydrogen atom. Sadly, this seems to be physically impossible, as none of the particles smaller than atoms are stable enough to be used in records.

Of course, records aren't made of hydrogen, they're made of the polymer pvc. One molecule of pvc is about 100,000 angstroms. This means that, if the cutters were actually removing single pvc molecules the vinyl records would have about 11 bits of resolution. Sadly, they don't get even that precise, though I'm not sure the actual precision. To get down to a record made of hydrogen atoms (possible under very low temp/very high pressure I suppose) one would need 19 bits. Anything beyond that is useless as long as the laws of physics hold.

Therefore, all other things being equal, digital is superior to vinyl. That said, mastering on CDs is often terrible while the mastering on records is often made somewhat better. This varies from CD to CD and record to record, and CDs are technologically far superior to records.


Really good explination and article on why Vinyl may sound better than CD equiv here.
http://www.audioholics.com/education/audio...s-vs-cds-part-4

May stimulate you  and your calcs further. Hope u like

Vinyl vs Digital and 24 bit vs 16 bit from vinyl.

Reply #42
Really good explination and article on why Vinyl may sound better than CD equiv here.
http://www.audioholics.com/education/audio...s-vs-cds-part-4

May stimulate you  and your calcs further. Hope u like


We've covered that many times before. That article has some major issues and can't be seriously used to prove a point.

http://www.hydrogenaudio.org/forums/index....showtopic=47827

Vinyl vs Digital and 24 bit vs 16 bit from vinyl.

Reply #43
...You can listen to a digital recording and think you're listening to vinyl; but you can't listen to vinyl and think you're listening to digital.

Therefore digital is superior as a delivery format because it's (sic) doesn't impose its own character on the audio. "Special effects" should be added because people want to, not because they're part of the delivery format.

This is a quotable quote. 

Vinyl vs Digital and 24 bit vs 16 bit from vinyl.

Reply #44
A vinyl recording will only sound like digital when the content is such that all the faults are masked. In other words, you can listen to a digital recording and think you're listening to vinyl; but you can't listen to vinyl and think you're listening to digital.

Sorry but I have to disagree. While it's true that vinyl can suffer pops, clicks etc it doesn't have to and when it doesn't I don't believe it has an identifiable sonic signature.

Vinyl vs Digital and 24 bit vs 16 bit from vinyl.

Reply #45
Sorry but I have to disagree. While it's true that vinyl can suffer pops, clicks etc it doesn't have to and when it doesn't I don't believe it has an identifiable sonic signature.
The noise floor on CD is a good 40dB below that of high quality vinyl. What's filling those 40dB of signal range if it isn't some kind of "identifiable sonic signature"?

Cheers, Slipstreem. 

Vinyl vs Digital and 24 bit vs 16 bit from vinyl.

Reply #46
My brief venture into vinyl was short lived because as soon as I turned it up, I got some massive feedback crap going on. The only solution was to turn the subwoofer down to the point where it was virtually doing nothing.

It seems that taking your system past about 85dB when its flat to 16Hz makes turntables do bad things.

Vinyl vs Digital and 24 bit vs 16 bit from vinyl.

Reply #47
Sorry but I have to disagree. While it's true that vinyl can suffer pops, clicks etc it doesn't have to and when it doesn't I don't believe it has an identifiable sonic signature.
The noise floor on CD is a good 40dB below that of high quality vinyl. What's filling those 40dB of signal range if it isn't some kind of "identifiable sonic signature"?

Cheers, Slipstreem. 

I'm not suggesting that vinyl has the same dynamic range as CD just that in my experience you can't tell the medium while listening to music in a normal domestic environment if the tell-tale vinyl clues (pops, clicks etc) are not present on the piece being listened to. I guess I should qualify that by saying that I'm assuming the music level is well above the noise floor

Vinyl vs Digital and 24 bit vs 16 bit from vinyl.

Reply #48
My brief venture into vinyl was short lived because as soon as I turned it up, I got some massive feedback crap going on. The only solution was to turn the subwoofer down to the point where it was virtually doing nothing.

It seems that taking your system past about 85dB when its flat to 16Hz makes turntables do bad things.

That doesn't have to happen. Proper setup of the turntable on a well damped surface will avoid problems with feedback. In my youth I used to turn up the bass until the walls rattled, and never had a problem with feedback.

Vinyl vs Digital and 24 bit vs 16 bit from vinyl.

Reply #49
Sorry but I have to disagree. While it's true that vinyl can suffer pops, clicks etc it doesn't have to and when it doesn't I don't believe it has an identifiable sonic signature.


Surface noise is required by physical processes. You can get rid of the gross noise due to damage, but surface noise is unavoidable.

Vinyl, furthermore, can easily be shown to have a particular set of distortion mechanisms that increase the loudness (using the term correctly) by much more than one would expect by the increase in intensity.

What is more, Vinyl almost always (system dependent but only usually on how much) will add L-R signal in midrange, and will also add L-R rumble.

The distortion and noise mechanisms in vinyl can actually sound better than the clean signal, sometimes, for very clean vinyl and playback.

I didn't say "accurate" I said "sounds better" as in "many people prefer".

The background noise on vinyl also, of course, often functions as "comfort noise". Very few concert halls are that quiet, I know, I've measured one or two myself...
-----
J. D. (jj) Johnston