Motu M4 USB C power issue questions

[Guitar Gaz]

I am thinking of upgrading my interface from the Audient iD14 mk1 to a Motu M4 - it has a lot of features I would find much more useful.

However, I have read about USB power issues - namely this is to do with USB C connectors when using with the USB 3.0 ports on my current iMac (Late 2015 on Monterey) and the power needs of the interface.

Also I am using Beyerdynamic DT990 Pro 250 ohms - and I saw somewhere that the power provided (if not USB C) would not be sufficient to drive these headphones.

So I have a lot of confusions in terms of current compatability of this interface, and then future compatability when eventually upgrading my iMac to one with only USB C ports.

Can anyone help with their knowledge on these "issues"?

[bayswater]

There was a long thread on the M2/M4 that started just about the time these were introduced. A few people noted the problems you mentioned. Bus power did not seem sufficient for some of the things people expected to do, and the input sensitivity on the “line level” inputs on the M4 was a problem in some cases. On the basis of that thread, I decided not to get one. Still looking.

[Guitar Gaz]

Thank you for your response - I will try and locate the thread - this is helpful if disappointing as some of the functionality like the mixing knob for playback/input is very useful.

[mikehalloran]

A number of my users have the M4.

Bus power is an iPadOS issue for some—big thread here—and the right powered hub takes care of that. One of my users is running his from a bottom of the line 2014 Mini with no issues. You should be fine.

Low impedance headphones like the SONYs can hurt your ears plugged into an M4. High impedance cans may require a headphone amp. I like the Mackie HM-4 ($40 here) and have asked a couple to buy it so we could both monitor when I’m over.
[https://mackie.com/en/products/audio-t ... /HM_4.html

When first announced, MOTU claimed you could use the M4 Line Ins for your keyboards etc. and hadn’t published the specs. They no longer advertise this because it isn’t true. Only If your keys have true Line level out can this work—most don’t. Otherwise, you will need a DI—I found passive and active DIs that work well. The CombiJacks handle keys and other instruments, of course. MOTU’s new M6 has 4 instead of 2.

The CL chip family that drives this is available up to 4 mic pre/instrument (CombiJack) + 2 Line Ins + 2 DIs + 2 ‘phone amps + MIDI. I wished that MOTU had released an M8 that had it all. The M-Audio AIR 192|14 is the only unit I found that does so I bought one.

[Guitar Gaz]

Thanks Mike - great info as usual and very helpful. I was hoping you would answer.

I think this M4 is the one for me as I am just using my late 2015 iMac and inputting and recording guitar and vocals, and driving my Yamaha HS8's and the DT990 Pro headphones. This interface can also facilitate a headphone amp. But thanks for the advice and it is best to be aware of issues.

Anyone who is interested, I found a thread on this which took some searching so here it is:

https://www.motunation.com/forum/viewto ... ce#p600705

[mikehalloran]

I forgot to mention cables. Many USB-C cables do not support USB 2. The MOTU does, of course. If the spec does not include 480KB/s, it does not. Some cable rebranders don’t seem to know that USB 3 is not backward compatible— cables must be designed to include it and many are compatible.

Turns out, this is a big issue for office printers. Readily available “USB-C Printer” cables only support USB 2. Problem solved.

[Guitar Gaz]

Thanks - worth bearing in mind.

[Tritonemusic]

I have my M4 connected directly into the back of my iMac Pro, and it works flawlessly. I never have problems with it losing power or anything like that. It works as expected. No regrets here, FWIW.

[Guitar Gaz]

I have my M4 connected directly into the back of my iMac Pro, and it works flawlessly. I never have problems with it losing power or anything like that. It works as expected. No regrets here, FWIW.

That is good to hear - thanks.