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[Andy Simpson]

I have been considering recently the idea that if I record two mono tracks at say 44.1/16, and mix them together (still in mono) - if they are both recordings of the same source, made at the same time, which interact with eachother when mixed - there is some argument that the output will need to be higher resolution than the recording was made at, to maintain the extra information.

If this is valid, are there any digital mixing engines which allow for mixing and output at a higher resolution than the recording rate, where the extra information will be preserved?

Any thoughts?

Andy

[seriousfun]

There are some mix engines that have a higher bit-rate than others. This can provide more precision in the calculations, arguably resulting in better sound (more accurate? less distortion?). A 64-bit calculation is called Double Precision.

Some converters will sound better at higher sampling rates than at lower ones, but Dan can provide the math to prove that this shouldn't be necessary.

My general recommendation these days is to acquire and work with audio at the highest bit-rate/sampling-rate that you can deal with practically, and leave conversion for the last step. The first beneficiary for this will be Seagate, Hitachi and Western Digital, but sonic benefits seem to be obvious.

[StudioRhythm]

andy_simpson wrote on Tue, 27 September 2005 09:09

I have been considering recently the idea that if I record two mono tracks at say 44.1/16, and mix them together (still in mono) - if they are both recordings of the same source, made at the same time, which interact with eachother when mixed - there is some argument that the output will need to be higher resolution than the recording was made at, to maintain the extra information. If this is valid, are there any digital mixing engines which allow for mixing and output at a higher resolution than the recording rate, where the extra information will be preserved? Any thoughts? Andy

I'm assuming you're talking about digital mixing. For example, ProTools mixes at either 32-bit float (LE) or 48-bit fixed (TDM, HD.) And, yes, (almost) any mixing or processing you do will increase word length so you actually have useful information at greater bit depth than the 16 you started with. You can either record your mix file at 24 bit or 16 bit, and you should use dither to preserve information below the cutoff point in either case (which some configurations do automatically.)

In answer to your question, all or almost all of the current digital mix engines allow this, and it would fairly difficult to find one that doesn't.

I'm not sure why you specify that they should be recordings of the same source, at the same time. That part shouldn't make any difference -- I believe any two files, unless they are bit-identical (in which case it would just be a gain change,) will mix together to create a new file with greater bit depth than either of the originals had.

[Andy Simpson]

Dan Feiszli wrote on Tue, 27 September 2005 18:42

andy_simpson wrote on Tue, 27 September 2005 09:09 I have been considering recently the idea that if I record two mono tracks at say 44.1/16, and mix them together (still in mono) - if they are both recordings of the same source, made at the same time, which interact with eachother when mixed - there is some argument that the output will need to be higher resolution than the recording was made at, to maintain the extra information. If this is valid, are there any digital mixing engines which allow for mixing and output at a higher resolution than the recording rate, where the extra information will be preserved? Any thoughts? Andy I'm assuming you're talking about digital mixing. For example, ProTools mixes at either 32-bit float (LE) or 48-bit fixed (TDM, HD.) And, yes, (almost) any mixing or processing you do will increase word length so you actually have useful information at greater bit depth than the 16 you started with. You can either record your mix file at 24 bit or 16 bit, and you should use dither to preserve information below the cutoff point in either case (which some configurations do automatically.) In answer to your question, all or almost all of the current digital mix engines allow this, and it would fairly difficult to find one that doesn't. I'm not sure why you specify that they should be recordings of the same source, at the same time. That part shouldn't make any difference -- I believe any two files, unless they are bit-identical (in which case it would just be a gain change,) will mix together to create a new file with greater bit depth than either of the originals had.

I specified the same source/same time to illustrate that I wanted more information about a single source.....and am interested in ways of generating greater definition than the original recording was made with....like M/S for example, where there is a direct mixing of 'same source/same time' going on.....

Which results in arguably a higher definition recording as a result - higher than 24bit - dither....?

Andy

[StudioRhythm]

andy_simpson wrote on Tue, 27 September 2005 15:54

I specified the same source/same time to illustrate that I wanted more information about a single source.....and am interested in ways of generating greater definition than the original recording was made with....like M/S for example, where there is a direct mixing of 'same source/same time' going on.....

That's fine, but as far as the mixing process, it doesn't make any difference either way. A mixer, digital or analog, doesn't "know" what it's mixing (and it doesn't care, either!)

Quote:

Which results in arguably a higher definition recording as a result - higher than 24bit - dither....?

What do you mean by this? Are you asking whether one of two options creates more "definition," or are you making a claim here? Also, would you mind defining "definition?"

[Andy Simpson]

Dan Feiszli wrote on Wed, 28 September 2005 00:39

andy_simpson wrote on Tue, 27 September 2005 15:54 I specified the same source/same time to illustrate that I wanted more information about a single source.....and am interested in ways of generating greater definition than the original recording was made with....like M/S for example, where there is a direct mixing of 'same source/same time' going on..... That's fine, but as far as the mixing process, it doesn't make any difference either way. A mixer, digital or analog, doesn't "know" what it's mixing (and it doesn't care, either!) Quote: Which results in arguably a higher definition recording as a result - higher than 24bit - dither....? What do you mean by this? Are you asking whether one of two options creates more "definition," or are you making a claim here? Also, would you mind defining "definition?"

Sorry to be unclear, I was just suggesting that one might deliberately aim to record multiple tracks of one source in order to create a higher resolution mix than was possible to record (ie. greater than 24bit).

Andy

[StudioRhythm]

andy_simpson wrote on Wed, 28 September 2005 03:35

Sorry to be unclear, I was just suggesting that one might deliberately aim to record multiple tracks of one source in order to create a higher resolution mix than was possible to record (ie. greater than 24bit). Andy

Ahh, gotcha. Well, it's true that you can create longer wordlengths by mixing two tracks together, but you can also create longer wordlengths by boosting an EQ by .5dB at 10kHz, or raising or dropping the level by any fraction of a dB, or compressing digitally by any amount... None of this added wordlength translates into an audible experience of higher fidelity or realism (except of course if it makes the track(s) sound better!) You'll certainly get a different sound by recording the same source with multiple mics, but the difference won't have anything to do with any added resolution. It will have everything to do with all the usual suspects of recording; different mic responses, phase interaction...etc.

When you talk about greater resolution than 24 bit, don't forget that a signal dithered from 48 fixed, or 32 float, or whatever, to 24 bit will contain a few more dB of signal than the regular 24 bit level.

[Gunnar Hellquist]

And while you are at it, remember that you will be very hard pressed to get more than 20 bits out of any real-world preamp + AD combination.

This all sounds like a very theoretical discussion really. Only way to handle that is to use math, and, well to be frank, sample theory math takes a bit of work.

G.