Just curious. I'm not familiar with audiophile lingo as of yet, but does slow means that the music can become cluttered, with little separation between sounds in the music, as the music gets more complex with more sound and faster tempo?

im not using audiophile lingo.
im just using a verb.

and u pretty much got the idea already.
it's just that the DAC is very detailed, that the limiitation becomes obvious. by comparison to normal soundcard, speed is about the same.
burnin also cures the problem, so it's probably the capacitors are new, so takes time to saturate and works.

again, as i mentioned earlier so many times..
I AM JUST BEING PICKY... since my benchmark for DAC is the lavry DA-11, which cost 60 times more expensive.

dun have to worry about the bass, cos this dac managed to improve the bass of my AD500 (the AD series is known for the excellent mids and soundstage, at the expense of sacrifing the bass). im not sure what audiophile term should i use to describe it, but it just sounds better, more pronounced, giving u the feel of the bass that u're looking for in a song, without being too punchy or causing distortions. hope im saying it right... but in my opinion, the way it improves the lower spectrum feels somehow more suitable for slow songs such as ballads, slow rock, certain types of jazz. probably not best for techno and trance. but i might be wrong, im really a noob here... do forgive me if im wrong...

i already said it, 2 things.
body and weight.
body is the fullness of the sound. it defines the size of the sound, not how loud the sound is. loudness and volume are totally different than body.
weight will be more to the feel of the sound when you hear it.. it feels and heard as heavy. light sound will feel and heard as light. when you hear heavy object fall to the ground, and light object fall to the groud, there will be difference in sound. the heavy ones will sound weightier.
both can be presented even on a very low volume.

the problem with body is, usually having more body and weight will reduce the speed of the sound.
a similar reference will be momentum. large and heavy object takes time to stop moving.
here, the sound takes time to dissapear. hence, slow.
what happens, is the decay will overlap with the next sound, causing distortion. this can be heard as muffled or sounds that are louder.

this is usually a tradeoff on cheap dacs that needs to be accepted. how they works?

if u want deep soundstage, you need to sacrifice depth, sounds feel compressed.
if u want wide soundstage, you need to stretch the sound width, sounds became unclear and smeared.
if u want separation, you need to thin out the sound, so that the separation is more obvious.
if u want speed, you need to sacrifice the sound body.

a very good DAC can do both weight and speed, body and separation, width and depth, without distorting the original sound. it has better control..
most dac usually does width and separation, therefore, smearing the sound, and thin it back. but you lose body and weight. speed naturally comes in with loss of body and weight.
this dac does the total opposite, improve body and separation, but losing the speed.

however, a good sound body is more pleasing and natural compared to thin sounding. if not playing fast tracks (techno, trance) this dac is superior in every way. on electronica, some of them are not so fast, a good body will be better. classical needs a balance of both, so preference is here.

also keep in mind, most mp3 already chopped down a 1411kbps cd audio to a 128-320kbps, you already lost at least 1/5th of the details, or in other words, smeared the details out.
thats why i said, most people wont notice.