I read with great interest this piece on Ry Cooder mastering with ITunes. Shock! He is not the first to use a car audio system as a final mix check before pressing. Scary, Uh?
I ran a test with JA's white noise from the Stereophile's Editors choice Disc Sampler and Test CD. I uploaded it into ITunes and then ran 1 minute of stock sound into my desktop using Cool Edit 2000 and my outboard M-Audio ADC.
The samples were between -15 & -12 db peaks. I then toggled in ITunes between the various levels of "sound enhancer" from low to high. There is a 1-2 second delay for the processor to kick in.
There is a visible and audible rise in the low end centering at about 110 hz that is up about +5-6db. You can also see and hear a lowering of the upper octaves which may account for Mr. Cooder sensing more "analog" and less edge. I thought I also sensed an additive process, reverb like, but of very low level added to the mix. I could be wrong about this.
I have always been one to have decent head units in my cars, generally using Kenwood higher end flip-face units. Long gone are the days when I would do subs and speaker retrofits. I am an indoor audiophile at my age.
My wife's Saturn Vue has a Nakamichi 7 disc cd changer and an awful speaker system. It is a car masquerading as truck after all.
I burned the disc and took it out to the SUV for a listen, flat and enhanced. I could tell little difference. I thought I heard some reduction in high end content, but again, I find this speaker system so poor that it turned out not to be the revealing test I had hoped for. Inside it was obvious.
My final test was of a recent piano recording test I did using our 7 ft Steinway B at church. I had tried to emulate JA