I have both the Heed and the 701s which are high resolution instruments which will match very well. However, as has been said. I too question your source and the material going through it.
It is true , the 701s are extended highly and will deliver what they are fed. If anything, the Heed is slightly rolled off in its HFs and it has pleanty of raw power so that isn't the problem . It has terrific gain and headroom.
In fact, I can't listen over the 1 o'clock position of the vol. pot. dependent upon the output of your source this should be consistant with your experience. Although, I do understand sound cards and ipods have lower preamp capabilitys than my sources.
I would suggest to hook up a CDP (borrowed even) and play a CD as a process of elimination experiment. I suspect then you can judge these statements of mine for yourself.
Although, it is true the k701s hfs are harsh when new. You say yours have 500hrs / check, scratch that.
Also it is true the k701s cymbals reproduction is not as refined as , say my RS-2s (same source) this will be exagerated and perhaps troubling at highest volumes; AND is recorded material dependent!
You say loud. Have you handed these to reasonable people to check for how LOUD you are listening? Just a thought.
Question , what are you using for I/Cs?
Question , what is this music being played , specifically.
Could also be possibly the compression of the material ?
I remain confident the issue is the source and possibly some combination of these above factors.
Best regards and good luck~
