Ridiculous amounts of boucing through A/D and D/A Converters

in a test designed to cure "Gear Hypochondria" *

I mix records using real outboard gear rather than plugins, because I think real outboard gear sounds best.

I use many channels of D/A and A/D converters to get the audio out of the computer and back again.

I even invented a plugin to compensate for the latency incurred on this audio journey , and with it I can correct this latency to 1/8th of a sample.

People often ask "doesn't the signal degrade every time you convert it?"

It's my job to make your record sound better than you expect it to, and I've always felt that the analog processing that I use

makes it sound so much better that I've often answered this question with the assertion that

a plugin seems to do more damage than a single D/A->A/D conversion.

After listening to Benchmark's 20 generation A/D-D/A test held at Avatar Studios during the 2007 AES convention,

I decided to run a "worst case scenario" test for myself.

I have Benchmark DAC-1s and several MOTU HD192s but my lowliest converter is my MOTU 1296.

The MOTU 1296 is a 12 channel A/D and D/A based on the AKM5393, a 96k converter with 117dB A/D and 120dB D/A s/n ratio.

I unpatched the gear from this 12 channel box and connected the inputs to the outputs of each converter channel.

Out of sheer laziness, I did this by connecting the cables at the gear end rather than using short patch cabled at the converter end.

I did say "worst case"...

Some channels went through several XLR->TRS cable to ->TRS->XLR barrel-> then XLR->TRS barrel to->TRS->XLR cable.

All cables were piled up behind the rack on top of 3 power supplies and 2 outlet strips... Like I said "worst case"

I imported 44.1 24bit audio files into my DAW, and inserted the 6 stereo pairs of conversion in series across the channel strip.

Each pass I bounced the file through the converters , imported that file, and -normalized it- (Like I said "worst case")

and repeated this process ten times to get 60 generations deep.


Listen to the results:

WARNING: These are LARGE uncompressed 24bit WAV files,

"right-click" or "control-click" and select "save target as"

drum overheads original

drum overheads after 1 pass of D/A and A/D conversion

drum overheads 60 generations later

piano original

piano after 1 pass of D/A and A/D conversion

piano 60 generations later


Chuck Zwicky
October 2007

*©2007 Chuck Zwicky