Interesting discovery with Motu M4 interface.

[John Vere]

I just watched this video where he reviews just about every common interface. https://www.youtube.com/watch?v=gMuA-2FbJxE

Right at the end he does a real quick overview of each. He got to the Motu M2 and rated it at the bottom of the pile. His claim was the headphone seemed to introduce distortion into the recording when turned up? Weird. 

Now I've always had trouble with my M4 since the day I got it 2 years ago. Randomly it would record audio distorted. A total system re boot fixed it. I also had to purchase a USB 3.0 PCI card just to get it working at all. I abandoned it last Sept when I purchased the Zoom L8. A much nicer sounding interface. But I bought the  Zoom for live performances, not as an interface,  so a bit of a pain to have to keep hooking stuff up. 

I built a new Computer in November and around January I thought I'd give the Motu M4 another chance so I wouldn't need to do this. It has not caused any issues with the new computer. I really haven't recorded anything serious in this time, mostly been just mucking about testing other DAW's,  making backing tracks and making You Tube narrations. 

So this guy had me curious about this distortion thing.  I fired up a project and put the M Oscillator on outputting from the master. I connected the headphones with a Y cable back to inputs 3/4 and set a new track up with that as input, None as the track output  just incase.  I then put the M analyzer on it.  Turned on input echo and got a reading of the correct sine wave. it looks clean to me? 

But here's where things get weird. I have the master volume way down because I don't really want to hear the sine wave. I crank up the headphones and the input level in Sonar is up around -6db. The M analyzer is not showing any distortion ( harmonics). Hmm.  

But I turned my monitors off. and unplugged the Y cable, plugged in my headphones to listen and when I turned  the headphones to off this crazy bunch of harmonics is showing on the graph? Anyhow the more I played around the weirder it got.  This thing has some sort of major screw up in the internal routing. Crosstalk etc. 

It's late but tomorrow I'm going to document this. Then I'm selling it.  

 

 

Edited April 17 by John Vere