[MacDV] Re: Sound input (was two other threads)

[Derek Roff]

> I'm very appreciative of this thread. I know I need some hardware and
> software soon to do a project. But could we shred this out a little
> bit for some of us with less experience?

Most Mac models haven't had microphone inputs for several years.  The 
Sound-In port expects a "line level" input.  A microphone input has much 
lower voltage and power, I am told.  A microphone pre-amp is one way to 
take care of that.  An audio mixer is another.  A USB sound input device, 
such as the Griffin iMic adapter is a third approach.

I have had fine results from the Mac's Sound In port, using the first two 
approaches, and via USB with the iMic.  I also have a $1000 (when it came 
out) Digi-001 PCI card with optical sound inputs.  I can tell the 
difference, but I wouldn't call it extreme.  The Sound In port is adequate 
for most of what we do for language teaching, which includes musical 
resources.

Vinyl LPs have a specific RIAA equalization curve.  Turntables have a very 
low signal output, which needs amplification to connect to your Mac, just 
as a microphone does.  However, vinyl also needs proper equalization, which 
the microphone doesn't.  If you can plug the turntable into an amplifier, 
which has an input intended for LPs, then this is taken care of.  The 
output from that amp will go into the Mac with good sound.

If you don't have access to an LP amplifier (if you plug into the CD 
connectors on a more modern amp, for example), then you will improve the 
sound by choosing software on the Mac that can provide the RIAA 
equalization.  If I remember correctly, the free Audacity does this.  I 
think that CD Spin Doctor, which comes free with Toast (at least in 
versions 5 and 6), also has a setting for vinyl equalization.

16-bit audio for DV is sampled at 48 KHz, rather than the 44.1 used for 
CDs.  Obviously, resampling digital audio can introduce artifacts and 
problems, but most people that I know don't consider this to be a problem.

Derek Roff
Language Learning Center
Ortega Hall 129, MSC03-2100
University of New Mexico
Albuquerque, NM 87131-0001
505/277-7368, fax 505/277-3885
Internet: derek at unm.edu