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I see Sasha jumped on the summing amp catch phrase as well.
http://www.area709.com/newsroom/trs/interview-sasha/
Coincidently I read this thread right before I read that article. I wonder how much differently I would have reacted to reading that article, had I not read this thread first. Either way, it's interesting to see both sides of it.
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huh, so adding air, noise, distortion, and bit loss with every a/d/d/a conversion is making his records better.....hmmm...
really odd, you read this thread right before the article and last night i'm listening to who killed sparky wondering about some of his production methods and stereo imaging......hmmmmmm... 
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Well those records are mixed in logic not a summing amp as far as what I've been told by the guy who mixes them.
What I can say is what your hearing is their expertise, not the gear.
Oh and you don't lose bits, just dynamic range, the bits are always fully there.
If he is hearing something as I said it's not the summing, something else going on. If you remember though I put a clip up here with a pro tools mix both done internally with waves plugs and then on an actual ssl. For the most part the mixes were pretty damn identical.
And I have yet to hear a comparison file that was done under critical testing situation where a summing amp had a clear advantage. There's plenty of guys on gearslutz saying they got one and heard no difference.
Probably the biggest advantage of these things is you could overdrive each stem a bit which of course would fatten up the mix. Since analog still generally has an advantage in this area I'd say that's the biggest thing that these summing amps could make difference wise.
In the case of the one Sasha was referring to, the SPL, it does have a widener and peak limiter on it. This is probably what is making the difference. I used to have the SPL Vitalizer Tube edition and on crappy mixes it did make a huge difference. When I learned to mix better though I sold it.
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Some more food for thought taken from GearSluts from Bob Katz:
"
So today, if you wish to mix outside the box, you have to balance the loss of transparency that comes from passing the signal through low-resolution D/A/D converters (unless you spend the money on the best converters) against the supposed advantages of totally-analog-domain processing and mixing. And these advantages, in my opinion, can now only be justified when using a superb analog console whose coloration adds a desirable color (e.g., space, depth, definition) that cannot be obtained any other way. But even that color that, say, an API console can give you, can be obtained without the full console. And the tradeoff is probably less than going through the entire console to mix. For example, mix digitally in the box, use lots of good analog outboard for your prime signals, and possibly send the entire mix through a single pair of superb D/A converters and a pair of API modules and into a single pair of superb A/D converters to capture the mix, or a 1/2" tape machine. The "magic sprinkle" that the API pair add to that mix can produce a final mix with a unique combination of transparency and color that can sound superior to the use of 24 or 48 or however many "cheap, low-class" converters feeding a full API console.
I've objectively tested the premise that there is no problem with the digital summing mechanism (e.g. Pro Tools "infamous" summing bus) by simply taking a pair of good analog modules and putting them on a digital summing bus. If the sound gets WIDER and CLEARER with simply a pair of analog modules added to a digital sum, that makes it clear that most (if not all) of the "improvement" people attribute to analog summing is NOT due to the summing but rather to the desirable character of the analog gear they are using.
In other experiments, conducted by Linn Fuston, he demonstrated equal performance with some analog summers, and worse with many. I can confirm that the transparent analog summer which does not objectively degrade the sound, is very rare. A client sent me a matched gain and pan mix done with the Dangerous 2-bus versus digital mix in the box, and objectively and subjectively, there was nothing special about the Dangerous Mix. If anything, it sounded a little vaguer and less clear. In my opinion, it did not add any desirable distortion. I performed the listening tests blind on the client's files.
In another test, a client sent me a mix done with the Sumo with its converters versus in the box. The Sumo was EXTREMELY transparent. The two mixes were virtually impossible to tell apart, blind or sighted. But there was absolutely no advantage to the SUMO. In both cases, no analog outboard was used to "complicate" the test.
In my opinion, the bar on the digital side has been raised so far. There is still plenty of analog "processing" that sounds superior to digital processing, but summing is NOT one of those processes. So unless you have a virtually-totally-transparent analog summer or one whose losses are made up by its character (e.g. API), then I would currently recomend ITB digital mixing combined with lots of good character-providing analog outboard.
Does this help make clear my current thinking?"
Notice how he clearly states that if anything the summing busses either in best case did nothing or in other cases actually degraded the sound.
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nice read! i just ordered Bob's book yesterday....
yes the mixes were basically identical. i didn't really hear a difference which would prolly mean 95% of the listening public (or more)wouldn't either. i'd think you'd have to have a very well trained ear to hear any difference and even then , blindfolded, alot wouldn't.
alright, well back to EQ'ing.......hehe.
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Paul Frindle on PSW Forums:
" Yes, I am only trying to point out the pitfalls one can fall into with digital mixing. Just like in analogue, digital also has it's foibles and limitations. A combination of metering methods, misunderstanding about the practicalities of sampling and current trends for loudness at all cost is leading you to conclude (understandably - but quite wrongly) that somehow DAWs cannot sum signals together without loss and plug-in processing is somehow fundamentally flawed.
The same effects and observations are also leading people to conclude (understandably) that higher sampling rates throughout the whole system are somehow philosophically better. And what you percieve within the sound of the errors being created is leading people to conclude that 'resolution' is somehow an issue because that's indeed what the errors sound like - even though that's nothing to do with it. This further encourages people to modulate at the extremes and virtually guarantees that the problems will occur that lead you to make those very conclusions - catch 22!
Digi are entirely correct - you cannot mathematically clip the summing bus this way - like I said it is not a summing issue - it's a question of what can occur WHEN you sum together many signals that may limit (from a reconstructed SIGNAL point of view) from time to time without you being made aware of it - cos no red lights occur."
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More Paul Frindle from PSW Forums:
" Ok now what does this mean for a mix? Well with all those mixed signals, cymbal crashes, HF EQ and limiting etc.. how close do you imagine the output signal can get to being a bit like white noise in places within a real production - even if none of the contributing channels hit the red light? Is this not the exact register of what we term as 'air' and 'resolution'? And people are aiming at max possible mix output levels on meters that do not show SIGNAL.
So why does an OTB mixer apparently sound better than an ITB mixer when you are modulating your digits close to 0dBr (sample value) all over the place? Well all those DACs (flawed as they may be) are acting to legitimately reconstruct your programme - before - you mix them all together and produce too many illegal signals that cannot pass out of your digital mixer! Paradoxically, the loss of sound quality due to all those converters is not as bad as the illegal signals created within the digital mixer by the 'too hot' signals you are trying in vain to pass out of the system.
It is not a summing issue at all (the one thing digits CAN do is add up almost perfectly). It's an illegal output problem caused by the fact that there are no meters that display actual SIGNAL in your whole mixing environment - you simply never see it happening.
So - go back and get your fav test mix back up on your W/S, re-mix the whole thing making sure that at every place in all chains (including between all plug-ins) never gets bigger than -6dBr. Make sure your final output after any limiting etc also never peaks beyond -6dBr. Now do the comparison between this ITB mix and a similar OTB mix. You might have a big surprise"
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more good stuff! definitely past the point of worrying about summing and conversion.
does seem to be quiet a bit of people have bought and are buying into.
Thanks Meds!
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The jist of what Paul is saying that it's clipping (I have also said this is really the only thing you need to be concerned about) that's the issue with digital mixing.
You have to remember that the meters in a DAW do not show you the actual signal level of your audio, they show the digital sample level. Digital samples are reconstructed through a filter to become continuous analog waves. This has the effect of sometimes reaching above 0, or as is known as illegal samples. You can test this in a DAW by taking a 0 db signal like noise and then running it through a lo pass filter set to around 20k (like an anti alias filter). The level will then jump sometimes up to 3-6db.
Intentionally clipping signals to get a hotter level can then lead to signals than when reconstructed or passed through internal filters results in higher peak levels.
One of the things the summing busses do as Paul states is they reconstruct the signal before you try to mix them therefore keeping you out of trouble.
His idea is to just keep your levels low in your DAW, -6db or so, that way you don't get into this situation. The audio then 'breathes' more as it's not being clipped and therefore you gain that clarity that maybe some people hear in the summing amps, but has nothing to do with actual summing.
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Bitfiend Wrote:more good stuff! definitely past the point of worrying about summing and conversion.
does seem to be quiet a bit of people have bought and are buying into.
Thanks Meds!
Ya you said it. I have a lot of respect for both of these guys, especially Paul. He was really the one who made me realize what was up on the digital and analog front and I was able to concentrate on what actually matters. With all the crap being thrown around on forums his posts are a godsend. It's partly what inspired me to start this forum, to carry over that integrity of knowledge.
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