Connecting two computers to MOTU M4

[marc]

What's the best method for connecting a second computer to my MOTU M4?

My setup currently is:

MOTU M4 <- PC
MOTU M4 Input 1 <- XLR Mic

I'd like to somehow get the audio from my MacBook into the interface so I can listen to both sources at the same time.

Currently I've tried a few USB -> Dual 1/4" cables into Inputs 3&4, but the sound isn't very good. If I plug into Inputs 1&2, it sounds better but then it seems to cancel itself out for some reason? And this is also problematic since I'm using Input 1 for XLR. I also tried a USB -> Single 1/4" out, but then it's just Mono replicated to both channels.

Is there a proper way to do what I'm trying to achieve? Not super versed on the ins-and-outs of audio stuff, so any help is appreciated.


Thanks

[HCMarkus]

Mac Headphone Output > Inputs 3/4 on MOTU might work nicely.

[marc]

I'll grab one and see if that works.

So far I've found that this cable is working best out of the ones I've tried. Minimal noise/hum.

[mikehalloran]

Mac Headphone Output > Inputs 3/4 on MOTU might work nicely.

Maybe. Those inputs are -16dB Line ins. If the signal is nice and clean but the input level is just not high enough, you'll need an active stereo DI
https://www.sweetwater.com/store/detail ... vel-driver

or a step up transformer.
https://www.sweetwater.com/store/detail ... el-shifter

I have used both of these on Line Ins 3 & 4 of an M4 and they work well (and are dead quiet) but the active DI gives you a hotter signal with a level control.

The Morley can sometimes be found used as the Ebtech Line Level Shifter with TRS jacks only—those with XLRs are wired parallel. Same otherwise (Morley owns Ebtech). A large number on eBay right now.
https://www.ebay.com/sch/i.html?_from=R ... r&_sacat=0

Let me add that the direct outs on my Yamaha P125 were useable but not as hot as I wanted into 3 & 4 through the Morley/Ebtech but splitting the headphone out gave me adequate levels. YMMV

[marc]

Mac Headphone Output > Inputs 3/4 on MOTU might work nicely.

Maybe. Those inputs are -16dB Line ins. If the signal is nice and clean but the input level is just not high enough, you'll need an active stereo DI
https://www.sweetwater.com/store/detail ... vel-driver

or a step up transformer.
https://www.sweetwater.com/store/detail ... el-shifter

I have used both of these on Line Ins 3 & 4 of an M4 and they work well (and are dead quiet) but the active DI gives you a hotter signal with a level control.

The Morley can sometimes be found used as the Ebtech Line Level Shifter with TRS jacks only—those with XLRs are wired parallel. Same otherwise (Morley owns Ebtech). A large number on eBay right now.
https://www.ebay.com/sch/i.html?_from=R ... r&_sacat=0

Let me add that the direct outs on my Yamaha P125 were useable but not as hot as I wanted into 3 & 4 through the Morley/Ebtech but splitting the headphone out gave me adequate levels. YMMV

Thank you for the suggestions! I picked up a used Ebtech on eBay and it seems to be doing the trick in conjunction with the 3.5mm -> Dual 1/4" breakout cable. For some reason it didn't work when I did USB -> Dual 1/4", it actually got quieter with the Ebtech.

[mikehalloran]

Glad it’s working for you.

The Morley/Ebtech LLS is a simple 2 channel (or 8 channel) step up/down transformer but I’m quite impressed by the low end response and lack of noise—both signs of high quality and excellent shielding. In addition, these eliminate a potential distortion issue that can occur with the M2/4 if the wrong cable is used with unbalanced sources (described in the MOTU manual).

I’ve had the chance to A/B against other passive DIs costing many times more. I imagine that I’d see a small difference in the bottom end response on an oscilloscope but I can’t hear one and that’s good enough for me. With bass, kick drum, low notes on a piano etc., anyone can easily hear the difference between good and not good enough when it comes to transformers—the worst are also noisy.