R/E/P Community

Please login or register.

Login with username, password and session length
Advanced search  

Pages: 1 ... 17 18 [19] 20 21 ... 23   Go Down

Author Topic: George....what's the resolution of analog?  (Read 79133 times)

Bob Olhsson

  • Hero Member
  • *****
  • Offline Offline
  • Posts: 3968
Re: George....what's the resolution of analog?
« Reply #270 on: September 06, 2005, 09:44:41 am »

I don't experience this same problem with high-end digital gear. Most digital gear is cheap and sounds cheap.

Sam Lord

  • Full Member
  • ***
  • Offline Offline
  • Posts: 139
Re: George....what's the resolution of analog?
« Reply #271 on: September 06, 2005, 11:01:11 am »

maxdimario wrote on Tue, 06 September 2005 05:47

now I'm gonna ask a very simple question, and I'd like some comments from you guys technical and non technical.

Why is it that when I listen to an analog recording with a chain consisting of: tube mic in perfect shape, tube pre (or exceptional low feedback solid state), discrete or tube analog recorder... I can hear the feel of the music more evidently than the equivalent path with digital recording?.

It sounds like a real person in the room with you, especially when reproduced on a good amp.


There must be an electronic distortion in the digital process that plays with what makes a sound realistic to our sense of hearing.

let's leave easily audible distortion out of it and focus only on the phsycological effect, please.

what could it be?


Hey Max, I experience this on every 16-bit recording of moderately complex music I have.  All of my CDs of music with more than about two performers, and this includes many lauded albums, have a distinct lack of transparency and usually other sonic problems compared great recordings on pristine tape and (admittedly noisier) LPs.  But a number of orchestral SACDs (don't own any DADs or DVD-As yet) really do it all for me.  My brief work with my own 24-bit recordings and supporting testimony tells me that DSD, 24/96, and perhaps all 24-bit media can really hit the ball out of the park with truly fine recordings and playback systems, IMO.  Regards, Sam    
Logged

Ronny

  • Hero Member
  • *****
  • Offline Offline
  • Posts: 2739
Re: George....what's the resolution of analog?
« Reply #272 on: September 06, 2005, 12:32:10 pm »

maxdimario wrote on Tue, 06 September 2005 05:47

now I'm gonna ask a very simple question, and I'd like some comments from you guys technical and non technical.

Why is it that when I listen to an analog recording with a chain consisting of: tube mic in perfect shape, tube pre (or exceptional low feedback solid state), discrete or tube analog recorder... I can hear the feel of the music more evidently than the equivalent path with digital recording?.

It sounds like a real person in the room with you, especially when reproduced on a good amp.


There must be an electronic distortion in the digital process that plays with what makes a sound realistic to our sense of hearing.

let's leave easily audible distortion out of it and focus only on the phsycological effect, please.

what could it be?



Digital is cleaner with high end systems. It's the analog distortion that is euphonic to your ears, not that the digi distorts more. The whole deal is you have to mix digital different than analog. It's typically going to be naturally brighter, doesn't matter if it's 24 bit. If converters are good quality, the only difference between 16 bit and 24 bit is the noise floor. The noise floor of 16 bit is 15dB lower than the self noise of the best Neumann mic.
Logged
------Ronny Morris - Digitak Mastering------
---------http://digitakmastering.com---------
----------Powered By Experience-------------
-------------Driven To Perfection---------------

bobkatz

  • Hero Member
  • *****
  • Offline Offline
  • Posts: 2926
Re: George....what's the resolution of analog?
« Reply #273 on: September 06, 2005, 03:40:45 pm »

Ronny wrote on Mon, 05 September 2005 22:24


This is an old post but thought I'd respond anyway as I find the method used at the office interesting. The sound tech dithered the room.




Actually, it's called "noise masking". And it is a science as well as an art. I once encountered an ignorant technician who put so much noise into the speakers it became annoying. The key is to make the continuous random noise mask the specular impact noise or talking and machines (and in the old days, typewriters) in the room. Just enough.

Same principle as restaurants that play background music actually seem quieter! It masks the sound of the waitresses dropping the silverware. Smile

BK
Logged
There are two kinds of fools,
One says-this is old and therefore good.
The other says-this is new and therefore better."

No trees were killed in the sending of this message. However a large number of
electrons were terribly inconvenienced.

maxdimario

  • Hero Member
  • *****
  • Offline Offline
  • Posts: 3811
Re: George....what's the resolution of analog?
« Reply #274 on: September 06, 2005, 03:57:26 pm »

Quote:

It's the analog distortion that is euphonic to your ears


no, that's not what I'm talking about. I'm talking about the human element coming through.

Quote:

I don't experience this same problem with high-end digital gear. Most digital gear is cheap and sounds cheap.


well, you should know, since you've worked with great artists, tube gear and analog recorders.

I've never experienced the same kind of vibe, but my experience only goes up to prism converters, which are pretty high-end, as far as relative cost.

I did eye an old grundig tube 1/4" mono portable tape recorder that had a recording of some german woman reading a text, and on that cheap consumer setup, the voice was so real I did a double take looking for the source.

with analog you get the vibe for cheap, who knows how good it can get for 5000 dollars for a home analog reproducer, vs. the digital alternative.

anyway I don't wish to conjure up the usual arguments.

what my question was founded on was to try and identify the single most damaging distortion that ...Bad... digital seems to have inherently, which causes it to sound lifeless, cold and unfriendly compared to it's analog equivalent.

Logged

Bob Olhsson

  • Hero Member
  • *****
  • Offline Offline
  • Posts: 3968
Re: George....what's the resolution of analog?
« Reply #275 on: September 06, 2005, 10:54:46 pm »

I think the most damaging distortion comes from not leaving enough headroom. A lot of digital gear simply hasn't got enough analog headroom to work with full-scale signals.

The first solid state mike preamp that I thought really stood up to the tube preamps we used at Motown was a prototype that my friend Pat Duran built for Deane Jensen. It clipped at something like +40. Upon realizing headroom was a common problem, I began experimenting with lower line levels and haven't looked back. I'm finding the same issues with digital multitracking. A lot of gear doesn't sound very good when you get within 6 dB of the top.

Ronny

  • Hero Member
  • *****
  • Offline Offline
  • Posts: 2739
Re: George....what's the resolution of analog?
« Reply #276 on: September 07, 2005, 01:50:51 am »

Bob Olhsson wrote on Tue, 06 September 2005 22:54

I think the most damaging distortion comes from not leaving enough headroom. A lot of digital gear simply hasn't got enough analog headroom to work with full-scale signals.

The first solid state mike preamp that I thought really stood up to the tube preamps we used at Motown was a prototype that my friend Pat Duran built for Deane Jensen. It clipped at something like +40. Upon realizing headroom was a common problem, I began experimenting with lower line levels and haven't looked back. I'm finding the same issues with digital multitracking. A lot of gear doesn't sound very good when you get within 6 dB of the top.


What is the physical reason for not getting a good sound above -6dBFs, Bob? Not that I'm a stickler for squeezing every bit out, especially at 24 bit, but you'll find a trainload of people on the net that say you get a better sound when you are as close to -0dBFS as possible. My personal tests have shown me that there is no difference in audio quality between -20 and -0dBFS and the best place to optimize sonics is on the analog side before the signal goes through the ADC.



Logged
------Ronny Morris - Digitak Mastering------
---------http://digitakmastering.com---------
----------Powered By Experience-------------
-------------Driven To Perfection---------------

maxdimario

  • Hero Member
  • *****
  • Offline Offline
  • Posts: 3811
Re: George....what's the resolution of analog?
« Reply #277 on: September 07, 2005, 06:30:49 am »

Regarding the levels being kept low, fair enough.

there is another mistery, though. Why is it that the analog recording (with the above-mentioned signal path) still sounds more human and natural feel-wise when there is slight clipping.

I'm still convinced there is something beyond traditional distortion, induced by improper operating range etc.

Intuitively I 'see' it as a more or less fine sandy haze from 3 KHz up. and Image instability?


admittedly, the more expensive converters may not exhibit this problem as much, probably because of the incredibly long amount of time that it's taking for people to realize that placing 2 or three cheap opamps before and after a converter GUARANTEES that the sound is not up to high standards..

but there is still something misterious happening, thd and clipping aside, I believe.

to me that's the resolution that's missing. noise is not a problem.

plus digital noise is not really 'noise' is it? it's noisy, but it's a result of the digitization process. it's a mathematical by-product.  
Logged

Eric Bridenbaker

  • Sr. Member
  • ****
  • Offline Offline
  • Posts: 342
Re: George....what's the resolution of analog?
« Reply #278 on: September 07, 2005, 08:09:00 am »

Paul Frindle has given a very comprehensive explanation as to as why it's a good idea to keep digital levels low, and why you can't always trust digital peak meters. It can be found here:

     http://recforums.prosoundweb.com/index.php/mv/msg/4918/0/64/ 4645/?SQ=14738cbb8d492e71f640277262efe15f

As far as that upper mid to high analog thing maxdimario is talking about, this might refer to what a lot of producers and engineers call "hair", part distortion, possibly some phase shift... It sits "on top" of the original sound, and can be used to enhance the perceived clarity and closeness of the sound. Hard to get this in digital, but it can be done, as in the HEDD unit.

When analog tape is driven, there is compression going on, particularly noticeable in the highs. Also, in some sources, especially drums there are these naturally occuring short transient peaks, about a millisecond or two in length, sometimes 10 to 15 dB higher that the rest of the signal. Analog tape will smooth these fast peaks right over, if driven hard enough. This, IMHO is a major part of what gives analog tape its sonic characteristics. Loud and soft at the same time, with a compression curve close in nature to the way the ear operates.

With an all analog path vs a digital one, I can hear a definite immediacy to the  sound with the analog, however the better digital converters get closer to this.

Cheers,
Eric
Logged

bobkatz

  • Hero Member
  • *****
  • Offline Offline
  • Posts: 2926
Re: George....what's the resolution of analog?
« Reply #279 on: September 07, 2005, 09:36:19 am »

Ronny wrote on Wed, 07 September 2005 01:50




What is the physical reason for not getting a good sound above -6dBFs, Bob? Not that I'm a stickler for squeezing every bit out, especially at 24 bit, but you'll find a trainload





Ronny, it's not the dBFS that Bob O was referring to, but the internal headroom of the analog electronics around and inside the converters. I've written extensively about this. Firstly, many lower cost (and even higher cost) pieces of gear are not designed with good internal analog headroom ABOVE the digital peak point.

Some integrated circuit opamps that I've encountered over the years seem to start to sound "ratty" as they approach their clipping points, their distortion characteristics shoot up as they approach clipping, especially at high frequencies. It is not fair to generalize, since the expertise of the designer, power supply design, bias, etc. count. But if I were to generalize, I'd say that caution is warranted as you approach the clipping level of an opamp, especially an integrated circuit opamp. I've encountered MANY opamp-based circuits that sound a lot better when driven to a max of 6 dB below clipping, rather than within 1 dB of clipping, which is a common practice in many designs to try and get high output levels.

Of course this is not universally true. The increase in distortion as clipping is appraoched is dependent on the implementation, brand and type of opamp, power supply voltages, how the opamp is biased. Regardless, I suggest caution in any case, especially in mixed signal (digital and analog) environments if the clipping point of the analog circuitry is being approached along with 0 dBFS (and measured 0 dBFS+ overs as well) at the same time, it's a recipe for ratty sound.

I've built unbalanced IC-based mixers with + and - 18 volt power supplies, using Burr Brown and other high quality opamps and despite the pedigree, I found they just sound better running "0 VU" at lower than 0 dBu, even as low as -6 dBu (0.0775 volts). Clipping point of these, running unbalanced, is nominally +20 to +22 dBu.

Thus, we are finding balanced preamps of high quality now which clip at far above +24 dBu, as high as +37 in some cases. The term I've been using for this necessary "analog headroom above 0 dBFS" is a "cushion". It's not a very scientific term, but it's the best I've got. To summarize: you should never operate certain solid state gear close to clipping; align the clipping point of the analog gear to AT LEAST 6 dB above the 0 dBFS point of the associated digital circuitry.

As for "people on the net saying you get a better sound when you are as close to 0 dBFS as possible", I tend to disagree. Given the evidence above, I'd say that is a generality as close to "he said, she said" as I've heard. Please let's hear some specific quotes from individuals who have tested and listened and reached these conclusions. If I were to generalize, I'd disagree; I'd say that "in general", you're a lot safer peaking somewhat lower than to full scale, for some of the reasons I mentioned above, and in addition, inaccuracies of digital meters, 0 dBFS+ signals, etc.

BK
Logged
There are two kinds of fools,
One says-this is old and therefore good.
The other says-this is new and therefore better."

No trees were killed in the sending of this message. However a large number of
electrons were terribly inconvenienced.

David Glasser

  • Sr. Member
  • ****
  • Offline Offline
  • Posts: 381
Re: George....what's the resolution of analog?
« Reply #280 on: September 07, 2005, 12:08:23 pm »

bobkatz wrote on Wed, 07 September 2005 07:36



I've built unbalanced IC-based mixers with + and - 18 volt power supplies, using Burr Brown and other high quality opamps and despite the pedigree, I found they just sound better running "0 VU" at lower than 0 dBu, even as low as -6 dBu (0.0775 volts). Clipping point of these, running unbalanced, is nominally +20 to +22 dBu.




I have a Calrec mixer, mid 80s vintage,  that uses run-of-the-mill chips, but operates at -4dBu (ie, 4 db below 0 VU or 0 dBu). I've wondered if that's one of the reasons it sounds so good, despite the multitude of TL072s and NE5534s (which I will replace... someday).
Logged
David Glasser
Airshow Mastering
Boulder, CO

dave@airshowmastering.com
www.airshowmastering.com

bobkatz

  • Hero Member
  • *****
  • Offline Offline
  • Posts: 2926
Re: George....what's the resolution of analog?
« Reply #281 on: September 07, 2005, 12:44:14 pm »

David Glasser wrote on Wed, 07 September 2005 12:08

bobkatz wrote on Wed, 07 September 2005 07:36



I've built unbalanced IC-based mixers with + and - 18 volt power supplies, using Burr Brown and other high quality opamps and despite the pedigree, I found they just sound better running "0 VU" at lower than 0 dBu, even as low as -6 dBu (0.0775 volts). Clipping point of these, running unbalanced, is nominally +20 to +22 dBu.




I have a Calrec mixer, mid 80s vintage,  that uses run-of-the-mill chips, but operates at -4dBu (ie, 4 db below 0 VU or 0 dBu). I've wondered if that's one of the reasons it sounds so good, despite the multitude of TL072s and NE5534s (which I will replace... someday).


It could be one of the reasons! Try running it hotter and see. The TLOs would be the first ones to replace.
Logged
There are two kinds of fools,
One says-this is old and therefore good.
The other says-this is new and therefore better."

No trees were killed in the sending of this message. However a large number of
electrons were terribly inconvenienced.

C-J

  • Jr. Member
  • **
  • Offline Offline
  • Posts: 80
Re: George....what's the resolution of analog?
« Reply #282 on: September 07, 2005, 02:25:39 pm »

Eric Bridenbaker wrote on Wed, 07 September 2005 15:09

Paul Frindle has given a very comprehensive explanation as to as why it's a good idea to keep digital levels low, and why you can't always trust digital peak meters. It can be found here:

      http://recforums.prosoundweb.com/index.php/mv/msg/4918/0/64/ 4645/?SQ=14738cbb8d492e71f640277262efe15f
Bob Olhsson wrote on Wed, 07 September 2005 05:54

I think the most damaging distortion comes from not leaving enough headroom. A lot of digital gear simply hasn't got enough analog headroom to work with full-scale signals.

What that link, and Bob are talking about, is the distortion caused by "shootovers between samples" created in the DAC's reconstruction filter, isn't it?
Doesn't an oversampling peak meter provide an easy solution for this problem? I always use RME Digicheck's Stereo Meter in OVS mode, to set the "Out Ceiling" levels of L2. It seems to reveal a lot of redouts, although the L2 meter peaks below FS.

My best,
C.J., Finland
Logged

Bob Olhsson

  • Hero Member
  • *****
  • Offline Offline
  • Posts: 3968
Re: George....what's the resolution of analog?
« Reply #283 on: September 07, 2005, 09:19:26 pm »

I think Bob Katz treats this issue very well.

Since I can't rebuild most of the gear I have to use, I simply take the time to find the sweetest sounding gain structure for the system I'm using.

maxdimario

  • Hero Member
  • *****
  • Offline Offline
  • Posts: 3811
Re: George....what's the resolution of analog?
« Reply #284 on: September 08, 2005, 05:38:07 am »

OK.

so there is an ideal level for each of the various gain stages, and we want to keep the output low so that the amps are running below their limits to the point that they don't sound harsh or strident or dull etc.

I can understand that as much analog circuitry in converters is fed by low voltage rails, and uses op-amps.

solid-state semiconductors do not tolerate large voltage swings, as do tubes, which can be fed high levels of signal on the control grids.

all electronics audio circuits work more ideally when the operating level is low enough for the circuit to work comfortably, and high enough so that the noise floor is not an issue.

these are some very important points, which are often overlooked, and are a lost art.

....regarding the human feel factor and intimacy on analog vs. digital?

You've mentioned that to get the same feel out of digital you need to go for the 24 bit high-end converters..ok

how about the 1" two track at 30 IPS on a discrete recorder?

I am not wanting to begin the analog VS. digital thingy again.

Just curious if anyone else who can hear this feel-factor has an idea of what it might be.

promise I won't insist on this issue anymore..honest..
Logged
Pages: 1 ... 17 18 [19] 20 21 ... 23   Go Up