macidiot said:
There is a clear difference between uncompressed WAV and 128AAC and 128MP3. However, once you get to 192 or 256, you can't really hear the difference. And obviously, there is no difference between wav and Apple lossless.
Perhaps some can hear the difference between 128 kbps MP3, 128 kbps AAC, and 16-bit PCM. Try as I might, I couldn't detect any difference that day with my Etymotic ER-4P headphones. That was weird no that I think about it, since I've even perceived that audio CDs made from 320 kbps MP3s sounded thin in the bass and harsh in the highs.
I've encoded some 16-bit PCM into 2-ch 448 kbps AC3 once and used
PC ABX, an M-Audio Transit (no, I don't own an $4,000 Apogee), and the same Etymotic headphones to do some double blind testing. Those two formats were perceptually indistinguishable, at least with my hearing that day, my preconditioning/expectation, limits of listener fatigue, and equipment.
macidiot said:
I can hear the difference on the Bose system in my car. And that is a poor audio environment with only fair frequency response. And on top of that, Bose systems generally suck. So I have no idea why you can't hear the difference.
As an audiophile for 13 years (started when I was 17), I've fallen into the Bose trap formerly, but they get more heat than they should. The new Bose Wave Radio, albeit overpriced, sounds very nice. Good bass response and very nice highs.
macidiot said:
Next time, try outputting through a quality receiver and some quality speakers. As in speakers that are accurate and offer a full dynamic range.
I appreciate the suggestion, but a reverberant environment such as one you are suggesting is definitely not ideal for error-free data collection. The numerous reflections and low-frequency room modes may obfuscate results. Let me divulge to you that the current audio system I'm building has dynamic range written all over it. It consists of four 10-inch woofer and two horns. I'm using modified diaphragms (thin aluminum jobs with damping coating) for the compression drivers. This is fed by two amplifiers, about 150 watts for the mids/highs and 350 watts for the bass per side. I plan to use a pair of subwoofers fed with 800 watts. This is fed by a DSP crossover and a DSP equalizer. I have a universal SACD/DVD-Audio player. And yup, SACD does seem to sound better than CD.
Sorry to brag about my pride and joy and go off on a tangent. What I'm trying to say is using quality headphones in a quiet environment is the way to go for detecting to subtle differences in audio.
