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Kiwiburger · 31st March 2006

I just had a worrying experience that has caused me to think up a theory why analog summing might be working it's magic (and how to emulate it). It seems this is a highly debated subject, and so far most people agree it's the noise and distortion of conversion and analog gear that explains the difference. This - I think - is a major new piece to the puzzle ...

I have a small studio rig in my home, away from my main studio, for messing with Cubase SX and experimenting with new toys and plugins. I use a Korg Z1, a Pentium IV with an Audiophile 2496, into a Mackie mixer and use Sennhieser HD280 headphones. Very useful, and I get to hear stuff I might miss with my monitors in the bigger room.

I was evaluating a reverb with a sampled hand clap, and I decided to try extreme left and right hand panning. I noticed that the exact same sample appeared to sound different from left to right. One side sounded faintly louder and brighter, but noticable. I was worried that maybe my hearing had changed a little.

Well - it turned out that my Mackie mixer (or possibly the Audiophile card) colors the sound slightly differently left and right. If I swap the cables around, I hear the difference in the other ear. (Phew).

Now this lead me to thinking. Analog gear depends very much on resistors and capacitors for level and eq and impedance matching, etc. We all know that components come in different quality levels, and different tolerances. Cheaper stuff will use low tolerance components. Higher end stuff might use 1% tolerance components or better. But still - tolerance is tolerance, and even 1% can have a significant effect that will be noticable.

The thing about DSP summing, mixing, eq'ing is that it is deadly accurate. Mathematically precise. Sample accurate. Boring even.

I've just realised that the best built analog summing device is going to nowhere near as accurate - even with 1% tolerance parts. That means that - like my Mackie mixer - left and right channels are going to sound slightly different. The pan will not be exactly zero at the centre detent. Even the eq 'sound' - even if no eq is activated - is going to be slightly different on each channel - within component tolerances.

Also - because it takes time for current to flow through longer circuits than throught shorter circuits, there will be subtle phase differences. Very subtle - I think the panning and eq effects will be more noticable - simply because of parts tolerances being fairly wide and fairly random.

As well as the noise and distortion - I think this explains the perception of better stereo imaging and more interesting mix sound.

With DAWs, there is a tendency to work to numbers. All the tracks we want centred, we probably set to exact centre. And with DSP, exact centre is exact centre. And the signal is perfectly equal each side. No wonder it's a little boring - and psycoacoustically, this has to sound a bit wrong. No mix of real musicians could ever be exactly all in the same spot.

I think, mix them up a bit.

Maybe somebody could make an Analogiser plugin. It could simply apply a random offset to panning and a random subtle eq change between each side. Maybe the odd phase shift by a sample. Maybe the plugin could be programmed so that these subtle changes are randomised - maybe using the plugin selection time to seed the randomiser. That way, you could insert the plugins on every track, and they would all be slightly different. Maybe choose a tolerance range. Or emulate various mixers - from SSL to Behringer perhaps for a wide range of extremes. A hint of saturation and even extremely low level white noise - also randomised, within user parameters.

Might work ...

I hereby submit this idea into the public domain - so any dsp developer can use this idea, for free or commercial use.

31st March 2006	#1
Kiwiburger Lives for gear Joined: Feb 2006 Posts: 4,075 Thread Starter	Analog summing emulation idea I just had a worrying experience that has caused me to think up a theory why analog summing might be working it's magic (and how to emulate it). It seems this is a highly debated subject, and so far most people agree it's the noise and distortion of conversion and analog gear that explains the difference. This - I think - is a major new piece to the puzzle ... I have a small studio rig in my home, away from my main studio, for messing with Cubase SX and experimenting with new toys and plugins. I use a Korg Z1, a Pentium IV with an Audiophile 2496, into a Mackie mixer and use Sennhieser HD280 headphones. Very useful, and I get to hear stuff I might miss with my monitors in the bigger room. I was evaluating a reverb with a sampled hand clap, and I decided to try extreme left and right hand panning. I noticed that the exact same sample appeared to sound different from left to right. One side sounded faintly louder and brighter, but noticable. I was worried that maybe my hearing had changed a little. Well - it turned out that my Mackie mixer (or possibly the Audiophile card) colors the sound slightly differently left and right. If I swap the cables around, I hear the difference in the other ear. (Phew). Now this lead me to thinking. Analog gear depends very much on resistors and capacitors for level and eq and impedance matching, etc. We all know that components come in different quality levels, and different tolerances. Cheaper stuff will use low tolerance components. Higher end stuff might use 1% tolerance components or better. But still - tolerance is tolerance, and even 1% can have a significant effect that will be noticable. The thing about DSP summing, mixing, eq'ing is that it is deadly accurate. Mathematically precise. Sample accurate. Boring even. I've just realised that the best built analog summing device is going to nowhere near as accurate - even with 1% tolerance parts. That means that - like my Mackie mixer - left and right channels are going to sound slightly different. The pan will not be exactly zero at the centre detent. Even the eq 'sound' - even if no eq is activated - is going to be slightly different on each channel - within component tolerances. Also - because it takes time for current to flow through longer circuits than throught shorter circuits, there will be subtle phase differences. Very subtle - I think the panning and eq effects will be more noticable - simply because of parts tolerances being fairly wide and fairly random. As well as the noise and distortion - I think this explains the perception of better stereo imaging and more interesting mix sound. With DAWs, there is a tendency to work to numbers. All the tracks we want centred, we probably set to exact centre. And with DSP, exact centre is exact centre. And the signal is perfectly equal each side. No wonder it's a little boring - and psycoacoustically, this has to sound a bit wrong. No mix of real musicians could ever be exactly all in the same spot. I think, mix them up a bit. Maybe somebody could make an Analogiser plugin. It could simply apply a random offset to panning and a random subtle eq change between each side. Maybe the odd phase shift by a sample. Maybe the plugin could be programmed so that these subtle changes are randomised - maybe using the plugin selection time to seed the randomiser. That way, you could insert the plugins on every track, and they would all be slightly different. Maybe choose a tolerance range. Or emulate various mixers - from SSL to Behringer perhaps for a wide range of extremes. A hint of saturation and even extremely low level white noise - also randomised, within user parameters. Might work ... I hereby submit this idea into the public domain - so any dsp developer can use this idea, for free or commercial use.