Quote:
Originally Posted by Viffermike
The great mystery is if the HU is downsampling all digital inputs or not. We know it does for certain, of course, when source material is downsampled and/or compressed: on-board HD rips, Bluetooth audio, streaming audio, Sat radio, HD radio. We don't know it does if the digital audio isn't compressed natively: CD, thumb drive with lossless files, any DMP fed through the USB input.
The comparison really needs to be between the digital input (or, in the case of the CD player, the output) and the analog input, the latter of which bypasses any possible digital-to-analog conversion by the HU. Based on what I heard this past weekend (and was gonna post about), I heard some differences between the CD player output and my AIFF files fed through the analog input, but not tremendous differences -- which leads me to suspect that the difference in tonalities are primarily DSP-based and not completely downsampling-based (but it could be jitter-based; depends on the sampling rate of the CD player). I played with some of iTunes' EQ settings and noted that the ones with bumps in the low and high bands (Jazz, Rock, Latin, etc.) helped even out the sound spectrum at given volumes, which is definite evidence that there is an immense mids-hump in the OEM DSP (we in the bass-playing word call it an EQ "hump"; the opposite is called a "scoop").
|
Ah, what the hell, I'll dig up the stuff tonight to run my phone through the AUX port using the WAV file, and compare it to the CD. Likely won't be able to actually try it until tomorrow morning, but I'll see what I can get.
EDIT: Hah! Had a patch cable in the Drawer-O'-Cables here at work. Just went out and alternated between the CD and the .WAV run through the AUX In from my phone. Some slight issues with trying to get the volume matched, but again, I really can't hear any difference. I'll guarantee I couldn't hear one if the engine were running.
I'll caveat this with the observation that people who bought the album I'm playing around the time they entered their teens may not have the best frequency response remaining in their ears, although testing a few years back showed my hearing then was better than the average person in his 30s.