Motu M4 Audio Interface Review

[Χ Ξ Σ]

By any chance, has this issue been fixed by a driver update?

I installed the latest driver on mac and it still takes 2-3 second to change the sample rate.

 

[artburda]

By any chance, has this issue been fixed by a driver update?

No, there‘s no new driver or firmware. As someone else already wrote: it‘s the hardware limitations of such a multi functional USB powered device. I guess compromises had to be made.

 

[JeffGB]

No, there‘s no new driver or firmware. As someone else already wrote: it‘s the hardware limitations of such a multi functional USB powered device. I guess compromises had to be made.

This really is only an ASIO driver problem. Unfortunately, the MOTU doesn't just work with Windows 10 drivers but if you are using equalization then you can't use ASIO and WASAPI (shared), which works with equalizer apo, doesn't have any delay when changing sample rates. That is the way I'm using my M4. I don't really notice any difference in sound between ASIO and WASAPI (shared) and since I need equalizer APO for my LS50's, it's all good. I guess it is actually a hardware limitation because I'm using windows to change sample rate, not the MOTU hardware. I just set windows to 24bit 44.1 since most of my music is CD quality so the only time windows resamples is on >44.1khz files.

 

[Interference]

I am surprised such a feature rich interface can run on USB-power only and with such great performance. I am a bit worried it can be kinda of sensitive on the host device (like would a Raspberry Pi be enough?)

 

[somebodyelse]

I am surprised such a feature rich interface can run on USB-power only and with such great performance. I am a bit worried it can be kinda of sensitive on the host device (like would a Raspberry Pi be enough?)

The M4 is designed to be bus powered, so it's current draw must be less than the maximum from the USB spec. It's meant to work with USB2 ports, so the maximum is 0.5A. The Pi can supply this, so long as it's not being asked to supply too much to the other ports at the same time, the details varying slightly by model:
https://www.raspberrypi.org/documentation/hardware/raspberrypi/power/README.md
If you're worried then just use a powered hub between them.

 

[Tks]

The M4 is designed to be bus powered, so it's current draw must be less than the maximum from the USB spec. It's meant to work with USB2 ports, so the maximum is 0.5A. The Pi can supply this, so long as it's not being asked to supply too much to the other ports at the same time, the details varying slightly by model:
https://www.raspberrypi.org/documentation/hardware/raspberrypi/power/README.md
If you're worried then just use a powered hub between them.

So how much can it draw if unlimited by an external powerhub? Does it go beyond the simple USB2 power specs (seeing as how it's a USB-C connector), or is it USB2 in spec, and the connector is simply a convenience?

 

[somebodyelse]

So how much can it draw if unlimited by an external powerhub? Does it go beyond the simple USB2 power specs (seeing as how it's a USB-C connector), or is it USB2 in spec, and the connector is simply a convenience?

The manual doesn't explicitly specify. It talks about using a USB-C - USB-C cable rated for USB2 if your computer has a USB-C socket, so I expect it's a USB2 device using a USB-C socket, and won't draw more power. I can't say for sure that it's not going to use Power Delivery to request more power if available, but I didn't spot anything to suggest it would when skimming the manual. I don't have one to test. It's not unheard of for interfaces to have different capabilities depending on the power available, but it's the sort of thing they tend to document and I didn't spot it. I may have missed it though, so have a look for yourself.

 

[chris719]

So how much can it draw if unlimited by an external powerhub? Does it go beyond the simple USB2 power specs (seeing as how it's a USB-C connector), or is it USB2 in spec, and the connector is simply a convenience?

USB Type C is just a connector, not necessarily linked to the USB interface spec. It's very unlikely that a USB 2.0 audio device is going to be a USB-PD sink, so you can probably count that out. It should be limiting itself to 100 mA until it negotiates for 500 mA, regardless of the power source. Just because it should, doesn't mean it does though. There are a ton of older products that simply don't comply with the USB 2.0 spec. Most laptop and PC ports will let an enumerated device draw much more than 500 mA, but it varies by vendor. I've seen PC motherboards that will deliver 1-2A from some ports. USB 3.0 raises the limit to 900 mA, but this device is 2.0.

 

[Tks]

USB Type C is just a connector, not necessarily linked to the USB interface spec. It's very unlikely that a USB 2.0 audio device is going to be a USB-PD sink, so you can probably count that out. It should be limiting itself to 100 mA until it negotiates for 500 mA, regardless of the power source. Just because it should, doesn't mean it does though. There are a ton of older products that simply don't comply with the USB 2.0 spec. Most laptop and PC ports will let an enumerated device draw much more than 500 mA, but it varies by vendor. I've seen PC motherboards that will deliver 1-2A from some ports. USB 3.0 raises the limit to 900 mA, but this device is 2.0.

I understand, it's not common to see USB-C connectors, with specs simply being limited to USB2, which is why I asked if there were any violations of the spec in some ways (like power here).

I have motherboards that support such higher output, which is why I wondered what the power spec actually is for the device.

 

[m_g_s_g]

 

[Rickydenim]

Hey guys can I get some help with a scenario. I currently have the Motu M4 connected to my Focal Shape 50 monitors and using it as a headamp. I am looking at getting the Focal Arche headamp and thinking I can go Motu M4 RCA out to Arche RCA input, then XLR out of that to my monitors. In this setup, I should set the Arche to '99' volume so not attenuating, and then set the volume by the Motu correct?
The Shape monitors don't have volume controls so hoping this is how gain will work.
Then for headphones, the Arch volume will control the. Can't use both at the same time obviously.

 

[AnalogSteph]

Would you even need the M4 any more? The Arche looks to be a DAC+HPA with USB in included (with a rather outrageous price tag if I dare say so - if you really just need a headphone amp this could be done about an order of magnitude cheaper). Plus, I can't imagine that the unbalanced connection as intended would be free from ground loop issues.

 

[JeffGB]

The MOTU M4 can definitely be used with the balanced outputs 1-2 used for the monitor and the RCA monitor outs as input to a headphone amplifier. Both of those outputs are controlled by the main volume control, so you would set your headphone amp at a volume that matched up with the efficiency of your headphones and speakers if you didn't want to mess with levels when going between speakers and headphones. I noticed the Arche includes a DAC but I see it has a set of RCA inputs. The Arche doesn't have an ADC so it's not a complete audio interface, so I see why you may be thinking of this.

 

[JimmyBuckets]

Just a side note. Hooked up my M4 to my Google Pixel 3xl and it powered up and seemed to chug along with no issues running straight off the phone. Powered my HD600's and sounded good.

 

[chris719]

It'll probably drain your battery pretty quickly, though.

 

[AllanDavidson]

The M4 is designed to be bus powered, so it's current draw must be less than the maximum from the USB spec. It's meant to work with USB2 ports, so the maximum is 0.5A. The Pi can supply this, so long as it's not being asked to supply too much to the other ports at the same time, the details varying slightly by model:
https://www.raspberrypi.org/documentation/hardware/raspberrypi/power/README.md
If you're worried then just use a powered hub between them.

Makes me wonder if a Phone/iPad can be used as a "DAW/Host" for bedroom musicians, and if not, how long until it does.

 

[somebodyelse]

Makes me wonder if a Phone/iPad can be used as a "DAW/Host" for bedroom musicians, and if not, how long until it does.

I thought they had been for some time - iOS having a low latency audio path while Android didn't for a long time essentially ceded that market to Apple. I believe it's a major driver for 'class compatible' interfaces too, as I don't believe manufacturers are allowed to write drivers for iOS.

 

[dwkdnvr]

Makes me wonder if a Phone/iPad can be used as a "DAW/Host" for bedroom musicians, and if not, how long until it does.

I believe iOS compatibility is an explicit feature advertised by Motu. Maybe not so much for the M4 specifically, but definitely on their higher end units.

 

[AllanDavidson]

Motu affirms they are (at least) compatible with iOS, but you may need a USB Hub to provide enough power, as you said.

Now looks like a theoretical "iPad DAW" only depends on Software.

https://motu.com/techsupport/technotes/m-series-ios-power

 

[AllanDavidson]

I understand, it's not common to see USB-C connectors, with specs simply being limited to USB2, which is why I asked if there were any violations of the spec in some ways (like power here).

I have motherboards that support such higher output, which is why I wondered what the power spec actually is for the device.

Actually it's the opposite, at least in the smartphone world, where 99.9% of the devices out there that uses USB-C are in fact USB 2 devices. It's pretty rare to have a USB 3.x on phones, except on a few high end devices.