Choosing bit depth while recording audio

Question

Hi,
First, the short version of the question:
Do you know of any simple audio recording app (ie: not a monster audio suite) which takes low CPU usage, and lets you choose the internal bit depth using for audio sampling (ie: sample at PCM16, at PCM24,...)  ?
Now, in case you need it, the long version of the question:
I'm digitizing my huge collection of audio tapes, with my G5 iMac (OSX 10.4). The quality of the recordings is somewhat low, so I don't need a high-end audio card, and I believe the builtin audio card of this G5 is more than adequate for this task (Burr Brown PCM3052 with support for PCM16, PCM24, and AC3 16).
I've done my first tests with the just-released new version of Audacity (2.0.0), which is compatible with 10.4 and higher, so I'm very happy to be able to install a brand-new application in 10.4.
Audacity works fine, but has a couple of issues:
First, you can choose the audio track bit depth, but not the internal bit depth at which you're sampling. In other words, I'd expect to use some selector to choose from PCM16 or PCM24 recording, which is what this iMac seems to support. However, I can only choose the storage bit depth, not the sampling bit depth. I suppose Audacity is recording at PCM24, but I've no way to test this.
Second, it takes about 40% CPU usage while recording (yes, I disabled the realtime graphics update of Audacity... if I don't disable it, usage becomes 60% or higher).
I tried Audio Hijack Pro (well, the last version supporting 10.4), and it won't let me choose the sampling depth either.
So... do you know of any simple recording app which overcomes this issues?
TIA!
cesarpixel

Answer 1

although I was looking for something simpler.
Compared to what you describe, my use of GarageBand sounds "simpler."
GarageBand is part of iLife, so it is meant to be easy to use, unlike big brother Logic.  Furthermore, I am using it in a very limited way. When recording, I just set up ONE track, which is pretty easy. 
GB records at the best possible quality, up to 24-bit.  I used 16-bit because my source was analog tapes and records, and I did not think it would make the final result any better.  The GB project file serves as my "master copy" for future enhancement.
The best part is editing the full recording of the entire tape/record, into individual songs, then exporting them to iTunes as 256 kbps AAC (or MP3) files, all within GarageBand.  A few of my records had skips, and I was able to edit them out by overlapping two tracks with the same portion of music, and carefully eliminating the skip at the transition between the two tracks.  Also, because the source is analog, there is noticeable background hiss when the music level is low.  It is particularly noticeable at the end of songs that fade out.  To make the hiss fade out along with the music, I gradually adjusted the master volume level downward to zero starting when the music level became low enough for the hiss to be noticeable.  That made the hiss fade out, which helped "hide" it.