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Summing Q: with and without a console's center section
Old 5th October 2014
  #1
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Summing Q: with and without a console's summing section

Hey all. I have some experience with using large format analog consoles (Neve and SSL) but not a ton, and certainly not enough from the design and building aspect to know what I am about to ask.

The understanding I have, is that when it comes to analog summing, what you really want are the channels of a console summed through the summing section. I have not done any a/b tests, but I can tell you from experience, that taking a couple of ch strips, and running a mix in and out, does not do a whole lot for the signal in terms of improvements, (color, depth, warmth, etc). So I wonder if you have a couple of ch strips, and were able to get your hands on the summing section of a good large format analog console - would running the audio in to the strips, then through the summing section, and then out be beneficial? Anyone have any thoughts/experiences they wish to share?

Thanks!
Old 5th October 2014
  #2
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Quote:
Originally Posted by drtechno View Post
if you are expirencing changes from the center section, and no parts have been changed, most likely its a power supply related issue or soldering on interconnecting backplanes. A tech can see if there is low +/- voltages on the ends.
I am sorry, I am not sure what you are talking about...?
Old 5th October 2014
  #3
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Dude - I appreciate your knowledge, but I am not sure what you are on about. I am trying to see how what you are saying relates to my Q. Maybe it does - I am just not sure I see it.

I do not currently have any stand-alone channels; I do not have a center section, nor any PSUs.

Cheers.
Old 6th October 2014
  #4
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Quote:
Originally Posted by Jeff Hayat View Post
The understanding I have, is that when it comes to analog summing, what you really want are the channels of a console summed through the center section. I have not done any a/b tests, but I can tell you from experience, that taking a couple of ch strips, and running a mix in and out, does not do a whole lot for the signal in terms of improvements, (color, depth, warmth, etc).
Thanks!
Your first sentence is correct. Maybe say summed through the summing amps (wherever they are in the console).
Running signal through a channel strip is not summing.

Denny
Old 6th October 2014
  #5
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Quote:
Originally Posted by drtechno View Post
the voltages drop on the power rails from center to the edges. as the power gets farther away from where it is connected on the backplane, the voltage drops as dc power isn't really efficient to distribute. sense lines that feedback to the power supplies helps overcome this.

I thaught you would want to know why the sound changes from center to the ends.
does the sound change from the center to the ends? I never came along this sofar, on which desks have you experienced that?
Old 6th October 2014
  #6
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Quote:
Originally Posted by dfchandler View Post
Running signal through a channel strip is not summing.
Correct! Hence my thoughts about adding the center section.
Old 6th October 2014
  #7
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Replace the term center section with summing section.
Granted, most summing circuits are in the center of a large console, but it is easier, in my opinion, to understand what you are getting at by saying summing sections(or summing amps).

Denny
Old 6th October 2014
  #8
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Quote:
Originally Posted by dfchandler View Post
Replace the term center section with summing section.
Granted, most summing circuits are in the center of a large console, but it is easier, in my opinion, to understand what you are getting at by saying summing sections(or summing amps).

Denny
Cool - thanks! Updated my post.
Old 6th October 2014
  #9
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Hi
The summing section (wherever it is physically located, often not where you think!) is essentially a 'mic amplifier' with (in the case of large desks) about 30 dB of gain. OK you can nitpick about current or voltage summing but this is the essentials.
As it has 'gain' and the bus itself is constrained by stray capacitance and inductance in the physically large frame of a desk the performance can be a 'weak point' in an otherwise 'clean' channel path. It is thus easy to 'colour' the sound unintentionally. Usually a lot of design work is put in to get it as good as possible, without letting the local radio station and taxis in. It can also be a 'pinch point' for headroom in some designs, especially if a pre master fader insert point is unbalanced.
Part of the 'magic', mojo or whatever of a summing bus in this form is that there are slight phase differences between channels and that by combination of channels you may get partial enhancement or cancellation which 'adds' to the interest of the resultant sound. This is particularly true of signals that start out 'phase coherent' at source, but may split to group paths and maybe direct path, possibly through effects units.
As to whether 'recreating' a bus setup is beneficial it is a moot point. Some modules on 'inline' desks actually have bus summing (would be associated with a track) built in. From this you COULD 'sum' to the bus in the module, perhaps add extra components to make it think there are 24 more modules and a whole bunch of copper tracks attached too, to 'simulate' it's effect in a full chassis.
Matt S
Old 6th October 2014
  #10
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Great info, Matt - thank you!
Old 7th October 2014
  #11
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Quote:
Originally Posted by Jeff Hayat View Post
Great info, Matt - thank you!
Summing boxes essentially give you sixteen channels of passive resistors with which you feed 8 already digitally summed stereo stems which are then "summed" by an active two channel amplifier at the end of the chain. Whatever "coloration", which is essentially noise and distortion, imparted is brought in at that point. In a nutshell - you're sending already digitally summed stereo sends down eight channels to be "re-summed" by the two channel active amp at the end of the chain.

You're also using a lot of digital to analog and analog to digital conversion - which may also be changing the sound.

Really great analog mixing boards were never made with the intention of coloring the sound in any way - if you look at specs for the best mixing desks, you'll see distortion and crosstalk specs in the inaudible range - no one sat around in the late 70's and said "wow, I love the spacious 3d harmonic distortion this Harrison console is imparting" .... , instead, they (we) wanted a clean and transparent board that did its job.

From your first post, I think it's apparent you've taken as fact a lot of the marketing hype surround analog summing, and you might do well to educate yourself to how these things actually work - otherwise you'll be throwing money at solutions to problems that may or may not exist, but might be solvable in other ways. For example a "more spacious 3d mix" has to do with recording at the source - in stereo, and with panning, and with certain types of reverbs - it has nothing at all to do with analog summing - in fact, ITB mixing will give you a more accurate panning and stereo separation representation - you cannot "improve" it with analog, you can only degrade it (which may be what you want).

Strapping something hardware either over the two bus, or on individual channels (via inserts using a patchbay) is certainly valid, I do it (though not as often as I used to) - tube compressors, eq's, sending something out to a guitar amp and back again are all fun things, but analog summing is expensive and really doesn't provide you great aural value.
Old 7th October 2014
  #12
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Hi
The obsession with 'separation' in either mixer or 'multichannel recorder' is often carefully omitting the considerable crosstalk of even good multitrack tape machines. Desks were aiming to be at least 20dB 'better' than the multitracks of the time. When the digital multitracks appeared the mixer manufacturers had to 'up their game' as the digits did not crosstalk.
This unintentional crosstalk in both 'tape' and desk domains added significant alterations to the 'sound' and as the mix engineer was listening to the results, would be adjusting EQ and whatever with this 'imperfectly separated ' tracks.
If tyhere were a 'semirandom' crosstalk plugin for your DAW you would be better able to enjoy the wonders of 'tape' without the actual tape.
Quote:
[Summing boxes essentially give you sixteen channels of passive resistors with which you feed 8 already digitally summed stereo stems which are then "summed" by an active two channel amplifier at the end of the chain.].
Surely you would be summing the separate tracks in your analog sum unit, not pre summed digital 'groups'?
Matt S
Old 7th October 2014
  #13
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Quote:
Originally Posted by Jeff Hayat View Post
Hey all. I have some experience with using large format analog consoles (Neve and SSL) but not a ton, and certainly not enough from the design and building aspect to know what I am about to ask.

The understanding I have, is that when it comes to analog summing, what you really want are the channels of a console summed through the summing section. I have not done any a/b tests, but I can tell you from experience, that taking a couple of ch strips, and running a mix in and out, does not do a whole lot for the signal in terms of improvements, (color, depth, warmth, etc). So I wonder if you have a couple of ch strips, and were able to get your hands on the summing section of a good large format analog console - would running the audio in to the strips, then through the summing section, and then out be beneficial? Anyone have any thoughts/experiences they wish to share?

Thanks!
i'm not sure what you're really asking, running a whole mix trough a couple of channels is probably not what you want, you want tracks or stems summed through the mixer. it is such a no-brainer that analogue summng sounds better. we're talking voltages, as in physics, not code as in halfway understood maths!

Last edited by Timesaver800W; 7th October 2014 at 04:49 PM.. Reason: typo
Old 7th October 2014
  #14
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Quote:
Originally Posted by Timesaver800W View Post
i'm not sure what you're really asking, running a whole mix trough a couple of channels is probably not what you want, you want tracks or stems summed through the mixer. it is such a no-brainer that analogue summng sounds better. we're talking voltages, as in physics, not code as in halfway understood maths!
All sound is analog, you don't hear digital math, it's nothing but an encoding and decoding scheme - the sound that reaches your ears is analog.

Any use of a summing mixer in the scenario you mention is still eventually "summed" in the digital domain, in fact, the final summed output is digitally encoded and decoded. The only thing that can happen in-between is some noise and distortion being introduced - not by the individual channels on the summing unit, but by the two channel makeup gain amplifier at the end of the analog summing chain.

If you have a problem with "math" somewhere in the signal chain, then the whole process needs to be analog - soup to nuts. Starting with tracking to tape, then making a tape master, then distributing and playing back the material at the consumer end with analog equipment.

That's how it was done when I grew up - in fact, i still have my turntable here with my vinyl records - those noisy disks with wow, flutter, ticks and pops and inferior dynamic range ...

Whatever floats your boat, I guess.
Old 7th October 2014
  #15
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Thanks for the info Sharp!

Quote:
Originally Posted by Matt Syson View Post
Hi
The obsession with 'separation' in either mixer or 'multichannel recorder' is often carefully omitting the considerable crosstalk of even good multitrack tape machines. Desks were aiming to be at least 20dB 'better' than the multitracks of the time. When the digital multitracks appeared the mixer manufacturers had to 'up their game' as the digits did not crosstalk.
This unintentional crosstalk in both 'tape' and desk domains added significant alterations to the 'sound' and as the mix engineer was listening to the results, would be adjusting EQ and whatever with this 'imperfectly separated ' tracks.
If tyhere were a 'semirandom' crosstalk plugin for your DAW you would be better able to enjoy the wonders of 'tape' without the actual tape.
I have always wondered about introducing crosstalk - with a bit of work, you would probably able to successfully emulate this in your seq. Of course the CT would (should) be random; you could automate faders and EQ plugs along the way to simulate randomness. But where would you start? Duping each track with very low level and extreme cut(s) on the hi-end seems like a good starting point... how much level would you need, and what would be the predominant freq. range on the CT chs?
Old 8th October 2014
  #16
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Quote:
Originally Posted by Sharp11 View Post
All sound is analog, you don't hear digital math, it's nothing but an encoding and decoding scheme - the sound that reaches your ears is analog.

Any use of a summing mixer in the scenario you mention is still eventually "summed" in the digital domain, in fact, the final summed output is digitally encoded and decoded. The only thing that can happen in-between is some noise and distortion being introduced - not by the individual channels on the summing unit, but by the two channel makeup gain amplifier at the end of the analog summing chain.

If you have a problem with "math" somewhere in the signal chain, then the whole process needs to be analog - soup to nuts. Starting with tracking to tape, then making a tape master, then distributing and playing back the material at the consumer end with analog equipment.

That's how it was done when I grew up - in fact, i still have my turntable here with my vinyl records - those noisy disks with wow, flutter, ticks and pops and inferior dynamic range ...

Whatever floats your boat, I guess.
yes the sound reaching your ears is analogue, if you tickle Elmo you will hear him laugh, and yes this sound is analogue. at what? 4 bits? of course you can hear the encoding.
this point has been made a thousand times and it is still daft (no offence).

if you really think that the sound from a mixer is only in the make-up stage on the stereo bus, then no, you haven't listened. or it might be an ear thing well whatever.

i do agree that the redbook format is a huge bottleneck. i want the people to get exited about recorded music again, we have been deliverng poop product for too long.
Old 8th October 2014
  #17
Quote:
Originally Posted by Matt Syson View Post
Hi

If tyhere were a 'semirandom' crosstalk plugin for your DAW you would be better able to enjoy the wonders of 'tape' without the actual tape.
Matt, fantastic idea for a plugin !

As a (M. Syson) console owner
I know exactly what you mean.

R.
Old 8th October 2014
  #18
About the thread question: Summing Q: with and without a console's center section

I think the console center section is the 'big positive difference' alternative to DAWs or summing without ccs.

My two cents...
R.
Old 8th October 2014
  #19
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Quote:
Originally Posted by Timesaver800W View Post
yes the sound reaching your ears is analogue, if you tickle Elmo you will hear him laugh, and yes this sound is analogue. at what? 4 bits? of course you can hear the encoding.
this point has been made a thousand times and it is still daft (no offence).
You're creating a strawman argument - yes, you can hear encoding up to a point, then higher resolutions make that moot, just as higher tape speeds mask analog tape deficiencies:

All recording mediums have low and high resolution mediums, analog tape ran at many different speeds, from 30 and 15 IPS at the high end, to 7½, 3¾, and 1 7/8 at the low. Of course you could hear the difference among those - just as you can hear the difference from high resolution digital to the lowest, in fact, many of us use 8 bit and lower resolutions as an effect, and quite like it.

Tickle me Elmo at 24/96 sounds great, annoyingly so, trust me

What's odd to me is while you deride digital as inferior, apparently you think it's ok enough to enclose your analog summing network - front and back - how can that be?

Quote:
if you really think that the sound from a mixer is only in the make-up stage on the stereo bus, then no, you haven't listened. or it might be an ear thing well whatever.
It's not an "ear thing", it's a logic thing - since you can't hear those individual channels unless summed, you can't know what you're hearing until you hear the final summed output - and that output has been amplified and I assume, given a bit of "color". Before that stage, the audio is simply passing through 16 channels of passive resistors ... of which you have no aural access to so you can't know what it sounds like, all you can hear is the summed result.

As an aside, summing on professional analog consoles was never designed to create a "sound" - the lowest possible distortion and highest resolution was always the goal. It was the same with mic preamps and eq circuits - just clean and utilitarian - no one sat around and oohed and ahhed over "sheen" and "focus" ... and no one ever used an external mic pre or eq for different "flavors" - that's all marketing hype designed to get you to spend money.
Old 8th October 2014
  #20
Quote:
Originally Posted by Timesaver800W View Post
i'm not sure what you're really asking, running a whole mix trough a couple of channels is probably not what you want, you want tracks or stems summed through the mixer. it is such a no-brainer that analogue summng sounds better. we're talking voltages, as in physics, not code as in halfway understood maths!
OK, let's not turn this into another digital vs analogue summing thread...the original question was to do with different options of analogue processing.
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