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One thing I dont't like about the Empeg's sound stage, is the 'digitized computer' noise you can hear in the backgroud if you listen carefully.
I would love if this noise wasn't there, but when I think of what the Empeg really is (a little computer) I don't mind abit, just lover my amps gain control.

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They've fixed this with the mark2's:)
-mark (no relation:) )


...proud to have owned one of the first Mark I units

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Regarding your point about bass and treble: You defininitely should notice a loss of very-high-frequency data in an MP3, but there shouldn't be any noticeable difference in the low-end stuff. The only difference there should be differences in the default EQ of the head unit's output. At least that's the way I understand MP3s to work, I don't know if that's really for sure the true case.

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The thing is though - ever since putting in the empeg, I've felt like I've had a single 8" in the back of my car, instead of the 2 10's that I have; i've had a hard time reproducing the bass quality playing mp3 files.. I'm not speaking of loud bass - i'm speaking of clear bass... When empeg introduced the advanced Eq, this got significantly better.. (it was almost like certain frequencies didn't make the cut for my crossover with the empeg, that did with my old head unit..) changing some of the values (sorry - an't remember which, and I don't have an empeg at the moment to find out (cry) ) did improve things, but I could never be satisfied with how it sounded, especially not accross 3000 tracks... One eq setting might sound perfect for one album, but would sound very poor on another..
In a sence, owning a collection that's been compressed using every which way possible, it was very difficult for me to eq my settings in a way to accomodate my entire collection... Yes, you can have different eq settings for different types of music, but it seemed as if the alpine's defaults were always good enough (I never changed them), were as I seemed to be constatly tweaking the empeg...

-mark

...proud to have owned one of the first Mark I units

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I can get the lower frequencies to be nearly indistinguishable (sp), but the trebble still sounds different - the empeg isn't as sharp, even at the highest bit rates.

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I have two observations to share.

First, many MP3 encoders will summarily throw out all frequency information above some threshold (typically 16kHz) regardless of bitrate. You might want to experiment with encoder settings (like LAME's -k) that avoid this cutoff.

Second, and let me preface this by saying I don't know how significant it might be in terms of what people are perceiving wrt sound stage and so forth, but I have evidence to suggest that the Xaudio MP3 decoder used in the empeg is only a limited accuracy ISO/IEC 11172-3 audio decoder. This means the reconstructed audio signal differs from a reference signal more greatly than a "full accuracy" decoder is allowed, but the difference is still within an acceptable limit (as defined in the ISO/IEC 11172-4 compliance standard.) The audibility of this difference is undoubtedly a subjective matter, but to the ears of an audiophile, the accuracy of the decoder may certainly have some influence.

-v

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Then again, there's a whole area of audio equipment (like the Sony ES compact disc players) which are more expensive and go to extra trouble to make sure the line-level output is perfect. But some of the extra things they do sound like snake oil to me, like using an extra-stable CD transport mechanism to reduce vibrations transmitted to the disc. I mean, you can prevent skips this way, but other than that, the data is digital and the transport mechanism has nothing to do with the sound as long as the bits are there.

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Let me start by putting this question to you. A CD-ROM can take 650MB of data, but a CD has 72 minutes of audio. 72 minutes of uncompressed stereo 16bit 44.1KHz music is 762048000 bytes, or 726.7 megabytes. So how do they fit that on there if a CD-ROM only contains 650MB?

Simple. CD Audio is stored in an error-[u]compensating[/u] format where as CD-ROM data is stored in an error-[u]correcting[/u] format. I'm not clear on the exact details, but basically the CD Audio is stored so that bit errors eventually even out - the audio will eventually get back to the correct position even if the immediate sample might be out by a least-significant-bit or two. CD-ROM data, on the other hand, is stored in an expanded format so that bit errors can be rebuilt transparently.

The point here is that CDs usually have a couple of hundred bit errors per second of play time (don't quote me on that, those statistics are coming from old memory). These bit errors are coming from fluctuations in the disc's speed and distance from the lens, scuff marks and prints, and other interference with the laser beam during playback. The playback algorithm is able to minimise the impact of those errors but sometimes it doesn't compensate completely; or, for your audiophiles, as completely as they'd like. Consider that the least-significant bit in a 16-bit sample represents about -96dB - in other words, in a 96dB signal they represent the bottom 1dB. So while ordinarily you may not hear bit, or even two- or three-bit, errors, they still exist in the audio and therefore can affect very sensitive listening devices.

Whether people's ears are 'very sensitive listening devices' is another question entirely.

The uptical pracshot of this is that some audiophiles might want to pay extra for a device which claims to have higher quality components to reduce the chance of these defects making it through to the audio stream.

Also keep in mind that these defects will affect a CD rip - the audio is [u]not[/u] coming off the disc in the same way as a file does.

Does that all make sense now?

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