Topic: A/D converter quality

[markinpdx]

I'm about to start digitizing a pile of ancient cassette masters. I'm using a Mac laptop, which has it's own converter, but I've got an old MOTU 828 I could also use. Is the MOTU's converter any better than the Apple's?

Also (I've read the epic saga of 48 vs. 96): at 48 KHz, if my primary aim is torrenting these recordings, is 24 bit PCM the way to go? I've got 32 bit float available (in Audacity), but I don't think I've seen it used much in the wild.

Thanks for any advice, I'd like to get this as right as I can the first time around.

[acidjack]

32 is for editing, not mixdown.

I think 16/44.1 is fine for ancient cassettes

[markinpdx]

32 is for editing, not mixdown.

I think 16/44.1 is fine for ancient cassettes

Thanks, acidjack. Is that a quantitative decision? I mean, does the dynamic & frequency range of the tape source make higher resolution redundant?

[Brian Skalinder]

I would guess the Motu 828 ADC is better, but I can't say for certain as I'm not familiar with it or the Mac internal ADC.  Generally, though, internal ADCs suffer from higher noise due to the nasty electrical innards of computers.

Don't forget to adjust your azimuth with every playback cassette side.

[page]

I would guess the Motu 828 ADC is better, but I can't say for certain as I'm not familiar with it or the Mac internal ADC.  Generally, though, internal ADCs suffer from higher noise due to the nasty electrical innards of computers.

the apple dac blows (IMHO) for this reason. I don't have any reason to suspect the input side is any better.

32 is for editing, not mixdown.

I think 16/44.1 is fine for ancient cassettes

Thanks, acidjack. Is that a quantitative decision? I mean, does the dynamic & frequency range of the tape source make higher resolution redundant?

basically yes, you're dealing with a natural noise floor (courtesy of the cassette and older gear) that is higher than the 96db that you get from 16bit.

Now, you could capture it at 24 just to be lazy with the settings, but once you get the hang of how the levels are on most cassettes, as long as you don't clip the input of your ADC, there isn't much reason to do 24bit and there isn't any reason period to torrent them...

[DSatz]

markinpdx, the dynamic range of the best reference Type IV (pure metal) cassette tape given optimal recording levels and Dolby "C" noise reduction is still less than the "resolution" of 12-bit PCM. With a 16-bit transfer, the bottom four to five bits will be doing nothing but registering noise. It wouldn't help in any way--either measurably or audibly--to have eight further bits registering that noise.

Whenever your destination medium has at least a 10 dB lower noise floor than your source medium across the audio spectrum, the noise of the destination medium will barely be measurable, let alone audible. With cassette recordings the difference will probably be more like 30 dB.

Back in the 1970s I often recorded classical concerts at 15 ips on a Nagra IV-S, which had anti-distortion circuitry that allowed it to put about 4 dB more signal than normal onto a tape before distortion would occur. I used Dolby "A" or telcom c4 professional noise reduction. Those tapes don't benefit audibly or measurably from 24-bit transfer, so I think that you can feel quite safe about your cassette recordings at 16 bits.

--best regards

[markinpdx]

Thanks all for the excellent and informative replies. I'll stick with 16/44.1... azimuth, check!

[it-goes-to-eleven]

You gotta TEST... and choose which sounds best.

Built-in sound cards are somewhat notorious for introducing noise, some of it intermittent, like when the hard drive spins up or the screen unblanks, etc.