Originally posted by Rimmer
Two points.
1. I have imported a few GB sessions on a friends iMac in to Logic Audio Express. I have to say (and I haven't got to the bottom of this) that the songs sound more polished before any effects and such like. I wonder whether Logic Express/PRO runs at a higher internal resolution than GB.
2. I would disagree with you that the 1/8" jack offers the same quality as even cheap USB interfaces. You may be forgetting that the quality of conversion is in the A/D conversion which many USB interfaces offer much better A/D conversion than an internal sound chip, 24bit or not. On top of that, there could be a lot more noise created during the conversion as the chip is internal and much closer to all the electronics that are ticking away close to the circuit itself. The beauty of having a decent A/D conversion (or D/A for that matter) a distance from the general electronics of the computer can often be very beneficial to the quality of the digital information resulting from the conversion. If you feel the need to check this out yourself. Go and audition a Tascam US122 in a music shop and compare the results after passing the same information through the minijack and internal A/D convertor in the Mac. It's not the same..
Regards. Rimmer |
1) GB, Logic Express, Logic Pro - connect to Core Audio. This is built right into the Mac OS X OS - and supports up to 32 bit / 10,000 KHz ( or more than any hardware available now, or in a decade likely ).
Switching computers, and opening in another program, the variables are many... Preferences, Buffer size, sample rate, audio path, - is say a compressor or other plug in on the track, even off, it can color sound.... Output can simply alter ANY part of Pan, EQ, Volume, FX, etc.
( One well known trick to "better" sound is loudness - 9/10 will say louder one sounds "better" )
I only say this because I know the people doing it, and that's what they said is under the hood.
2) No, I didn't "forget", what A/D D/A conversion is, and I didn't say PB G4 = cheap USB - In fact, built in is substantially higher quality.
Yes, I know internal "can" cause "Noise", this is always what companies with big wall warts tell you... but Mackie sticks the electromagnetic hell IN the mixer - and claims that is better......
I have conferred with experts, listened, examined, measured, heard debates, and checked all this from digital file examination - is it identical? To sound, and comparing blind A/B testing.
Today, though I am sure a salesman (on commission) may say otherwise, AD/DA converters are all far above what human, dog, or bit for bit analysis can determine.
Apogee, Pro Tools, M Audio, Emagic, MOTU, - even use the same exact chips - while "saying" they have better "Sound" (!)
Yes, I have a Tascam 1224 - USB -> Audio involves far more than A/D conversion. ( And Tascam hardly guarantees better sound - often not even supporting Balanced connectors - which reject noise )
So, "If" you use the same cable, same place, same everything - the USB driver - audio settings, etc. all have some impact. So, sample rate, bit rate, driver, all change audio preferences - As does setting input level on 1224 - a LOT.
Finally the USB spec is horrible in terms of "Timing". It loosely has zero requirement for "Time based Media" - Audio/ Video - Like Video camera's all support IEEE 1394 ( Firewire) Which is time sensitive - obviously if I waver sample rates - garble is the better part this possible mess.... So, MIDI & Audio have to put Time Stamping into the Audio data - so it knows where = when = and reassembles based on tags - I'm not sure how well it works - those who know, refuse to use USB at all.
Actually, if you use S/PDIF - there is no conversion - digital to digital. the 24 bit 96KHz built in a Powerbook - would be identical to source. So, "If" you have a PB, and only use 2 inputs - the built in is actually better - in real life - and has been built to work as a Core Audio I/O with 32 bit support.
Tascam USB driver is not open source, so no idea what they have in there, but those who do, will not touch it... cough!
-a subjective difference may indicate destructive gain stage - which louder, seems better, but the audio is actually degraded....
Evaluating all these variables, and knowing absolutes are not simple, I submit the quality, all around, is far superior Built In ( and the Mic built in, is as good as a basic Sure - or better - ) and possibility for noise/ signal degradation/ errors/ conversion is 100 x less likely on Internal.
This is like Hard Drive debate. You can play 96 tracks back on a Powerbook. Yes, it's slower than many HD's. but if you use 1/2 that at most.... the important thing is, it works well for 48 tracks or less.... Sure there are faster ones, but speed of HD is a non-issue these days.
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