I found same noise on BOTH 1/4" input channels. This issue is ONLY with analog inputs, so bit-bucket users have no problems with analog input related noise.
As mentioned in other posts about M-Audio MT1, engineering, production design, and final production quality assurance testing is split among different groups on different continents. M-Audio is truly an international effort.
It would seem there is lack of engineering follow-through on various stages of product development. So when the product is finally shipped, there is a lack of refinement and quality check process typical of all-done-in-one place engineering/production like typical of a company like Sony who rarely ships out anything with avoidable shortcomings.
This engineering-to-production process is fractured with M-Audio on MT1 and MT2 so performance/quality as pertains to what is finally shipped is often plagued with shortcomings. Or so it seems , as we too often get a kinky, untested M-Audio product needing many fixes
after we have purchased.
A short 0.5MEG 24bit/88.2K wav clip of the unbalanced 1/4" input noise at -35 dB reference input gain is here for download:
www.sonicstudios.com/mt2ub14i.wavAfter 5 days with no response to the online request for service (with sent noise graphic) posting on their website, I resorted to calling technical service by phone to discuss my MT2 and what might be done. So far, they've agreed to 'repair' the excessive noise and low-pass filtering at 88.2K problems I found within a 3-4 week time-frame.
Stay tuned.