Refuting the external analog mixer theory

[markwayne]

Tell me, why would a mix get "smaller" with an ITB mix? Analog or digital the resulting summation produces one waveform. It's all addition. One happens with ones and zeroes and the other with electrons. Does adding more numbers together eliminate existing numbers? Boy, that's new math. You could easily argue that summing tracks in analog makes the mix less defined because of the increased noise when summing, thus blurring the sound. At least digital busses don't add noise.

Oh I agree with you in theory. If you could take time out of the equation, I doubt there would be any difference left beyond the "coloration" added by the analog gear. The problem is that math whether new or old takes time. Audio can be a highly time-senstive medium. Since there is always a certain latency involved in summing digitaly, it represents a potential problem. Under ideal conditions these time-domain errors can be anticipated, calculated, corrected and/or off-set, but if you tax the CPU enough to move the system beyond its capacity for error correcting, you'll hear problems. It's not that subtle when it happens.

Wayne

[Timeline]

64 bit, quad 5ghz, 10gb ram, 100gb per vsec throughput. Hmmmm?

[pounce]

well, i don't mind digital, but i think that radar sounds better than pro tools. i have a digital console and i use DP, so i am not anti-digital by any means - but not all digital is equal.

audio quality is at least partially subjective. so i don't think that there is a single "correct" answer to this question. i do think that digital audio still has room to improve, and that it's still kind of in it's infancy. i can't give any techie style asnwers for what is wrong with current digital audio other than to say that in a few years in the future it will probably be better and these improvements will erode the arguments against digital audio that still exist. maybe longer word lengths, higher sample rates, i don't know what will best address the limitations of current digital audio. however, these improvements are likely to come. and with them, digital summing that will appease even today's digital critics.

some of the earlier criticisms of digital audio were proven to be correct as we found out that the inital claims made by digital proponents were not correct. the claims that digital audio, by having a frequency response from 20 to 20 at least on paper, was all we would ever need. turned out that the filters, clock jitter, converters, and limitations of 16 bit audio became apparent and the luddites who thought analog still sounded better were right. digital audio improved and addressed those issues. at least somewhat. what i don't know is how much more improvement we can expect reasonably in the near future. the fact that these discussions were had earlier in the digital audio age leads me to ask if the naysayers are hearing -something-. while i no longer am using an analog console, i haven't discounted the effect of an analog console with respect to tracking and or summing. i think things like the 3d audio discs are quite cool, and allow folks to come up with their own opinion on the matter.

i still tend to think a console is a necessary thing in a studio. i need the pre's, the faders, the aux sends for monitoring, etc. for total studio i/o, monitoring, patching, workflow, etc. you could do the same thing with enough external pre's, monitoring systems, control surfaces, etc. - but it wouldn't be cheaper or necessarily more integrated. so for me a console is a great thing.

as for summing, i think all we know for sure is that console summing will tend to sound a little different than itb summing. at least the comparisons show that. so it is up to the engineer to know the gear, the project, and choose what is most appropriate given that situation. so it's just another engineering concern. on lesser digital systems the difference is likely to be greater. on really hot digital systems the difference will probably be lesser. and certainly show digital in a better light anyhow. i doubt any summing solution is going to be a magic bullet - if you haven't engineered the mix right before this point the summing won't be what makes or breaks you. i am simply suggesting that while i do think there will be a slight difference in sound, other engineering factors are far more important and what sound you do like will be subjective.

so i think that nothing is proven or disproven in thread like these. there are slightly different results between itb and console summing and you just have to gain stage things right and choose what sounds best for your project. of course summing on crappy analog boards won't help anything.

[waxman]

ding, ding ding! # 78 on the hit parade... with a bullet... Big Wave Dave you owe me!

Shooshie awesome... congrats to you and mom on your daughter going to Yale. Now that is truely the greatest work of your life. That puts everything in perspective. I have an 11 (Christa) and 13 (Luke) year olds. I would say I have about 5 years before new gear will be a long forgotton luxury and tuition that makes a SSL 9000 look cheap. Just about the time you Shooshie are amancipated. And you can probably get my Trident for about $28 bucks...

Ok I give up. I will return the Trident unless you put it on layaway for 2012. I will buy a trackball and be content watch the little bar fill up on the screen instead of listening to the mix as it goes by. I will lament the days of 2 inch tape, razors, marshalls and moogs that you could touch with your hands. They paved my paradise and put up a parking lot. That does it I am gonna go watch some reruns of Gilligan's Island...

[Timeline]

ding, ding ding! # 78 on the hit parade... with a bullet... Dave you owe me!

Shooshie awesome... congrats to you and mom on your daughter going to Yale. Now that is truely the greatest work of your life. That puts everything in perspective. I have an 11 (Christa) and 13 (Luke) year olds. I would say I have about 5 years before new gear will be a long forgotton luxury and tuition that makes a SSL 9000 look cheap. Just about the time you Shooshie are amancipated. And you can probably get my Trident for about $28 bucks...

Ok I give up. I will return the Trident unless you put it on layaway for 2012. I will buy a trackball and be content watch the little bar fill up on the screen instead of listening to the mix as it goes by. I will lament the days of 2 inch tape, razors, marshalls and moogs that you could touch with your hands. They paved my paradise and put up a parking lot. That does it I am gonna go watch some reruns of Gilligan's Island...

OK Skipper.

Justwake me when an api 48x24x48 is $28 bucks!

[Splinter]

Most IOs are all chip based in the analog portion of their design, not discrete. The UA 2192 happens to be class a discrete and it really sounds exceptional.

Possibly improving front ends and mixing in the box would help more...
Don't think digital is nearly there yet although its a bunch of fun and easy to work with in the box.

Great observation, Gary. The frontend has a profound impact and chip-based designs won't yield the same result. I agree, digital ain't there yet, but I'm not sure it will ever be what we expect out of analog. Digital is actually "truer," more naked. Analog wraps its harmonic and transient "enhancement" around it, thus smoothing and sounding easier on the ear. So, the question would be: Is there really anything "wrong" with digital or is it just the new medium we need find other ways to soften?

[Splinter]

64 bit, quad 5ghz, 10gb ram, 100gb per vsec throughput. Hmmmm?

Yummy, indeed. ... Somewhere over the rainbow...

[Timeline]

64 bit, quad 5ghz, 10gb ram, 100gb per vsec throughput. Hmmmm?

Yummy, indeed. ... Somewhere over the rainbow...

Sooner than you think

Dual quads too in a few. Next year will be exciting though and maybe we can look back at these threads and have a laugh.

We do need to press the IO makers to get with sonics that are higher in headroom, punch and clarity. I never wanted to leave MOTU for my RME's but now that I have them they sound superior to MOTU stuff. I do wish they produced more headroom but I could say that about all of them except the UA.

[Splinter]

This post is from a thread going on over at 3dAudio. I thought it was very astute. Here's the link if you want to hear more from the big dogs: http://www.3daudioinc.com/3db/showthread.php?t=8694

Thnaks for all the kind words re: my earlier post on levels. This is something like a "Jehova's Witness" thing for me. I'll stop any time, anywhere, to preach on this subject, given the chance.

Here, in a nutshell, are the salient points as I see them:

1) A 24 bit PCM word can express a theoretical limit of 144 db of S/N.

2) The analog electronics in the converter limit the performance to a functional 100 db of S/N. (slightly more in some cases, but I'll use a conservative figure and make the point even without those extra 6 db)

3) As long as the noise floor in any recording system is lower than the noise floor in the signal you're recording, you will record the full dynamic range perfectly.

4) No source you've ever recorded had a signal to noise ratio higher than 80 db, and most would be much much lower. Lynn suggests that he RARELY sees the source's noise floor lower than 70 db down, and even then, rarely. Assuming that his peaks are not at full scale, his typical source S/N ratio must be in the 50-60 db range?

This means that if you record your (best ever) 80db S/N source into a converter so that the highest peak just reaches -19 dbFS (below full scale) on the meter, that the noise floor in your signal will be louder than the noise floor in the converter. You needn't record it any hotter than that.

In the real world, you could get away with peaks around -28 dbFS, and be PERFECT. Any higher than that is totally unnecessary.

Conclusion: There is absolutely NO benefit to tracking hot.

But does it hurt to do it? Read on...

1) Your microphone preamp is set to perform best (gritty distorted choices aside) peaking around 0dbVU. This is where you'd have it set if you were recording to analog tape, hitting 0 on the VU meter. Plug that same source into most converters, and you get peaks around -20dbFS to -14dbFS, depending on how the converter is setup.

The scientists who developed this system understood the situation, even if the guys who wrote the digidesign manual don't! They EXPECT you to record with peaks around 0VU (-18dbFS on the digital scale). They KNOW about the signal to noise deal I explained earlier. That's why they chose to put the nominal level so "low" on the meter.

When you record hotter, with peaks at -6dbFS, lets say. You're driving your mic preamp 12 db hotter than you did yesterday in the analog world! That's going to add a subtle layer of distortion to your project. And they say analog sounds so much better than digital - maybe its because most people use their analog gear incorrectly when recording to digital. Maybe the "problem with Pro Tools summing" is really the effect of tracking too hot?

I've heard people say "My Neves can handle outputs +24db according to the spec, so what's the big deal?" My Neve 1073s are great sounding workhorses. They are rated for a LOT of gain. Still, they definitely sound very different even at +12. Very different. Maybe a good choice in some cases, but not the norm.

2) If you have a peak at -2dbFS, and you try to boost a mid range frequency +3db on an equalizer, you're going to clip.

Another unintended detriment to tracking hot is that you no longer have any headroom in your plug ins! It is true that in Pro Tools, you can recover lost headroom in the mix bus by lowering the master fader. This isn't true in an analog console, where the distortion has happened in a summing amp "upstream" on the master fader. In that case, the master fader only lowers the volume of the distorted signal, which remains distorted.

In Pro Tools, the master fader is actually a co-efficient with each individual fader before summing. This means that if you're clipping the mix bus, you can pull the master fader down, and fix it. Great. But what about the plug ins across each fader? They aren't affected by the master fader (thank god, or your compression levels would change etc) but neither are they protcted by the master fader. If you're clipping the mix bus, and have your master fader at values lower than unity, then odds are that you're clipping some plug ins too.

3) Most analog gear doesn't like inputs that are 12db and more over 0, even if the spec says they can take it. If you track hot, you're causing a nightmare for analog gear that you may choose to insert during the mix. Keep your levels around 0dbVU, and you can leave the digital domain freely without adding more sonic grunge.

Conclusion: Tracking hotter than 0dbVU can easily cause distortion in any number of places in the chain.

So, to reiterate:

1) There is absolutely NO benefit to tracking hot.

2) Tracking hotter than 0dbVU can easily cause distortion in any number of places in the chain.

If you want to hear the result of tracking too hot, and what it does to Pro Tools, listen to any Lenny Kravitz record. believe me, he uses all the best vintage gear, with gobs of headroom etc. There is no shortage of Neve, Helios, Fairchild, Neumann, Telefunken or whatever on his sessions. The sound of those records is entirely due to the tracking and mixing levels.

"But how do I get my product hot?"

There is a point to having a final mix that peaks at -0.1dbFS. if you are going to have a 16 bit version, if you want to be commercially competitive, if you like to see all the lights light up - sure, I do it every time. The point is i bump it up LAST in plug ins across the master fader. That way, the mix is all properly gain staged, with lots of headroom right up until the last thing juncture. Then if I raise the result to just below clipping after having the benefit of proper levels all the way through, everything is beautiful.

If you are a non believer, try it. The amount of air, detail and image is astonishing. In fact, eventually you may find that Pro Tools is actually TOO CLEAN and transparent! Then you'll start introducing purposeful distortion in your mix - distortion that YOU control at the mix is a very different animal than the unwitting accumulation of crud that comes from tracking too hot all along.

One last thing: Some analog gear really does sound better a little hot. My ADL tube compressor sounds sweet on my lead vocal when the output is a few db hot. Good! I'll track it that way. I've still got more than 10db of headroom on the meter, and for plug ins etc later - fine. But if you insist on tracking with peaks around -6dbFS or higher, you deserve what you get.

[Timeline]

There are so many things about that post i could blow apart but he's totally wrong on one point, summing amps can basically never be clipped in properly designed boards. I know, I built a few. They are set for around 40db gain after the resistive net but a +4 input usually produces a -40 result at the summer OP. It takes all 40 or 50 inputs to even match a -10. On the line amp follower however it's different. That is generally why we fade sub-masters. A proper analog summer requires a 2-1 xformer to reestablish noise floor where no clipping ever occurs at -0- level.

I could go on but low level signal issues with digital are not in his lexicon, only specs. Forget that!

[Splinter]

There are so many things about that post i could blow apart... I could go on but low level signal issues with digital are not in his lexicon, only specs. Forget that!

You should read the rest of the thread.

[Timeline]

maybe later. have to get back to daily grind...

cheers
g

[David Polich]

Okay, what a long interesting thread this has become! Great posts from everyone.

From reading every single post over and over, here's what I've gleaned:

1. You don't need a high-end external analog desk to get a great mix. It can help, but really, a great mix is up to who is doing the mixing.

2. A high-end external analog desk or rack mixer CAN make things sound better, but again it is as much due to the mixing skills of the engineer as it is anything else.

3. Some people have gotten great results with mixes externally bussed.

4. Some people have gotten great results doing ITB mixes.

So, it seems we've come full circle. Back to square one - "start with the kick drum, then the bass..."

I will always believe that all the math in the world doesn't mean squat. It's the ears and skill set of the engineer. And it's also the song and the arrangement. That is what makes great records - it is at least 90% song.

[waxman]

I agree with Big Wave Dave 100%

[James Steele]

I will lament the days of 2 inch tape, razors, marshalls...

Marshalls are still here and ain't goin' anywhere, thank God!