Motu M2 Review (Audio Interface)

[Trell]

What would I gain in terms of sound quality by getting a better amp?

You could get one that has more output power, in case it’s not loud enough for you. For me that happened sometimes with some content that had a low level. Otherwise the headphone amp in the M2 was just fine.

That was with some 250 Ohms Beyerdynamic DT-880.

 

[Ember]

Hello everybody, new here so i am sorry if maybe i should make a thread and not make questions directly on this thread,
but it made sense when i have seen the topic was the interface i am using. I have very little knowledge in terms of impedance and other technical aspects, my question is the following:

For recording E-guitar, would it be better to use a TRS connector instead of XLR or that would not change much?

My setup is as follows: Fishman Fluence modern active pu -> Radial JDI -> Motu M2

I ask because i had some troubles in getting the sound i wanted from the DI, and read that it would be better to have a 1 mega ohm impedance for electric guitars.
But (from what i understand, maybe wrong) because i am using a DI box which has a output of 600ohm it should be more than enough to use the XLR to connect, correct?
i have both cables (XLR to XLR and XLR to TRS) and was wondering which was best in terms of maximizing quality or other aspects i am missing.

Thank you in advance to anyone willing to help or explain

The impedance is lower on the XLR connection. Have a look at the attached image.

 

[Omid]

Hello everybody, new here so i am sorry if maybe i should make a thread and not make questions directly on this thread,
but it made sense when i have seen the topic was the interface i am using. I have very little knowledge in terms of impedance and other technical aspects, my question is the following:

For recording E-guitar, would it be better to use a TRS connector instead of XLR or that would not change much?

My setup is as follows: Fishman Fluence modern active pu -> Radial JDI -> Motu M2

I ask because i had some troubles in getting the sound i wanted from the DI, and read that it would be better to have a 1 mega ohm impedance for electric guitars.
But (from what i understand, maybe wrong) because i am using a DI box which has a output of 600ohm it should be more than enough to use the XLR to connect, correct?
i have both cables (XLR to XLR and XLR to TRS) and was wondering which was best in terms of maximizing quality or other aspects i am missing.

Thank you in advance to anyone willing to help or explain

Ideally, you want to go from low impedance to high impedance so there is less power loss and less frequency range error.

That said 600 ohms going into 2.5Kohm for the XLR input is a reasonable ratio: you’ll get 80% of the voltage you would compared to the TRS. You won’t break anything, so if you have the adapters, try both ways and see if you can hear a difference.

 

[Exopowk]

This is a review and detailed measurements of the Motu M2 Audio Interface (DAC, ADC and headphone amplifier). It is on kind loan from a local member and costs US $179. I previously reviewed Motu M4 which is its larger brother.

The M2 has the look of other Motu products:

View attachment 109298

I like the color LED bar graphs as if you don't get sound, you know whether it is or is not getting to the product. Front panel sockets are for input sans the 1/4 headphone jack. The back has the only set of outputs (both balanced TRS and RCA):

View attachment 109299

The overall feel of the product was good. Compatibility was great without me having to use their control panel or driver except to set the ADC sample rate as needed.

M2 is bus powered using that USB-C connector which was nice.

Motu M2 Measurements: DAC
Measurements of the M2 started on a sour note using the unbalanced output with one channel being 8 dB worse than the other due to noise. Strangely, as it sat there for a few minutes, the noise subsided fair bit and improved that channel to 104 dB SINAD:
View attachment 109300

Fortunately there was no such issue when using the TRS balanced output:

View attachment 109301

This is quite a competent performance for such a budget, multifunction device:
View attachment 109302

Dynamic range was good:

View attachment 109303

As was jitter:

View attachment 109304

Unfortunately even though Chinese manufacturers have figured out how to get rid of the increase in intermodulation distortion when using ESS DAC chips, the news has not gotten to M2 yet:

View attachment 109305

Unlike pro interfaces with their own power supplies, there is not much more output to be had than the 4 volts I test:
View attachment 109306

I was pleasantly surprised to see a proper reconstruction filter that chops everything off at 22 kHz rather than the common 24 kHz:
View attachment 109307

Linearity was almost perfect:
View attachment 109308

Distortion rises with frequency but not enough to be a concern:
View attachment 109309

View attachment 109310

Motu M2 Measurements: ADC
For this testing, I used TRS input in the front:

View attachment 109311

Specification is confusing but seems to imply if you use TRS, you have lower gain and reference would be 16 dBu. That did not happen with my testing. Clipping occurred at a low 2.5 volts as opposed to minimum of 4 volts. You can see that in this sweep as well:

View attachment 109313

Notice also how distortion rises well before clipping.

Overall ranking is average and below Motu M4:
View attachment 109316


We also see rising distortion at both ends of frequency spectrum:
View attachment 109314

Fortunately our hearing thresholds are higher in those extremes so this is less of an audible problem than pure engineering.

Frequency response was wide enough at 192 kHz sampling:

View attachment 109315

Motu M2 Measurements: Headphone Amplifier
Power is usually an issue with these types of headphone outputs so let's jump right into that:
View attachment 109317


View attachment 109318

Not much power but what is there is good prior to clipping. So if you use a sensitive headphone, this may be a workable solution.

Conclusions
The DAC implementation in Motu M2 is quite good especially given the price. Clearly attention was put in to produce a good design. On ADC side, looks like they wanted to tier this down below the M4 and performance there is just adequate. Headphone amplifier is barely adequate from power point of view but otherwise, not bad.

Still, the package is well worth considering over a DAC-only solution. You get nice VU meters, mic and analog in ADC and passable headphone output for an extra $80. Good trade in my book.

Overall I am happy to recommend the Motu M2. If you can though, spend the other $60 and get the M4 as that has better ADC and two more channels.

------------
As always, questions, comments, recommendations, etc. are welcome.

Appreciate any donations using: https://www.audiosciencereview.com/forum/index.php?threads/how-to-support-audio-science-review.8150/

Sorry if i'm dumb for asking this, I don't really know what I'm going with, but shouldn't the DAC clip or have some harsh distortion pass a certain volume? I am experiencing some distortion in sound as i get my MOTU M2 monitors output knob after ~60%, I was wondering what could be the issue here. My monitors are two Yamaha HS5.

 

[Omid]

Sorry if i'm dumb for asking this, I don't really know what I'm going with, but shouldn't the DAC clip or have some harsh distortion pass a certain volume? I am experiencing some distortion in sound as i get my MOTU M2 monitors output knob after ~60%, I was wondering what could be the issue here. My monitors are two Yamaha HS5.

The M2 has a max output of 16dBu for TRS output and 9.5dBu by RCA. The Yamaha monitor input sensitivity is -10dBu.
When you turn up the volume past a certain point you far exceed the maximum voltage the Yamaha allows. That’s why the speakers distort.

 

[Exopowk]

The M2 has a max output of 16dBu for TRS output and 9.5dBu by RCA. The Yamaha monitor input sensitivity is -10dBu.
When you turn up the volume past a certain point you far exceed the maximum voltage the Yamaha allows. That’s why the speakers distort.

Ohhhhh, makes so much sense, I get it now! Thank you a big lot

 

[Exopowk]

The M2 has a max output of 16dBu for TRS output and 9.5dBu by RCA. The Yamaha monitor input sensitivity is -10dBu.
When you turn up the volume past a certain point you far exceed the maximum voltage the Yamaha allows. That’s why the speakers distort.

Can two different speakers with the same -10dBu sensitivity, have different sound limit in volume, or will they perform just the same amout of output power?

 

[unpluggged]

Can two different speakers with the same -10dBu sensitivity, have different sound limit in volume

Not only can, but it's the usual case. Sensitivity is a metric of input signal level that will cause the amplifier's output to reach saturation and clip.

 

[Exopowk]

So what metric should I look for in case I'm looking for output power?

 

[unpluggged]

So what metric should I look for in case I'm looking for output power?

SPL per unit of input voltage (also could be called sensitivity, which may cause confusion). Weirdly enough, this common metric is not specified for your particular model. And it's a bit strange that you did manage to get the speakers to clip before they even reached high enough volume. Probably it's worth trying to reduce the input sensitivity by using the LEVEL knob on the back of the speakers, as described in the manual (the output volume will also be reduced, but the speakers would at least be better matched to your interface, and you would be able to better use M2's volume control range).

 

[Exopowk]

SPL per unit of input voltage (also could be called sensitivity, which may cause confusion). Weirdly enough, this common metric is not specified for your particular model. And it's a bit strange that you did manage to get the speakers to clip before they even reached high enough volume. Probably it's worth trying to reduce the input sensitivity by using the LEVEL knob on the back of the speakers, as described in the manual (the output volume will also be reduced, but the speakers would at least be better matched to your interface, and you would be able to better use M2's volume control range).

Oh I guess I see a problem, there's a LEVEL knob on the back of the speakers, which has the options MIN on the left, +4db, and -10db on the right, and it is set to +4db, what does this mean? And should I change to -10db?

 

[AnalogSteph]

So the LEVEL knob is actually labeled with input sensitivity achieved, which potentially is rather confusing. Looks like there is a 12 dB adjustment range - from +4 dBu for full rated output to -10 dBV. A fair few monitors traditionally tend to be like that, though on larger models it tends to result in people complaining about excessive noise level and lack of adjustment ange.

You should not be able to get the input to clip before the speaker drivers / power amps call it quits. All I can imagine is that you may mistakenly have used unsuited cables to connect the two (e.g. instrument cable 1/4" TS to same - what you want is either balanced patch cable 1/4" TRS to 1/4" TRS or 1/4" TRS to XLR male), or that the M2 is defective.

Try turning up the input level control to about midway. If sound level reached prior to distortion is higher then, there is something amiss in your setup. If it remains the same, you are actually running into the speakers' limits.

 

[Exopowk]

So the LEVEL knob is actually labeled with input sensitivity achieved, which potentially is rather confusing. Looks like there is a 12 dB adjustment range - from +4 dBu for full rated output to -10 dBV. A fair few monitors traditionally tend to be like that, though on larger models it tends to result in people complaining about excessive noise level and lack of adjustment ange.

You should not be able to get the input to clip before the speaker drivers / power amps call it quits. All I can imagine is that you may mistakenly have used unsuited cables to connect the two (e.g. instrument cable 1/4" TS to same, or 1/4" TS to RCA), or that the M2 is defective.

Try turning up the input level control to about midway. If sound level reached prior to distortion is higher then, there is something amiss in your setup. If it remains the same, you are actually running into the speakers' limits.

Yup, you're right about that. I am stupidly for some reason using TRS intrument cables to connect my M2 to the HS5, where was my mind when i did this!? Will it be fine if I just replace the cables, also, can you tell me if these are apropriate: https://www.thomann.de/pt/cordial_cfm_15_vv.htm
Thank you so much for your help and attention!

 

[unpluggged]

And should I change to -10db?

No, it will increase the sensitivity even more. Turn the knob towards the MIN mark until your speakers stop clipping when you set your M2 volume to maximum.

 

[phoenixsong]

Yup, you're right about that. I am stupidly for some reason using TRS intrument cables to connect my M2 to the HS5, where was my mind when i did this!? Will it be fine if I just replace the cables, also, can you tell me if these are apropriate: https://www.thomann.de/pt/cordial_cfm_15_vv.htm
Thank you so much for your help and attention!

TRS balanced cables are good, it's TS cables that you'd want to avoid. Also, just set your speakers' input sensitivity to +4dBu, your Motu M2's speaker output knob to max, and adjust the final level via the speakers' own volume knobs at the rear. If you want to avoid distortion/clipping while using Windows, there is a separate thread for that in this forum

 

[Exopowk]

TRS balanced cables are good, it's TS cables that you'd want to avoid. Also, just set your speakers' input sensitivity to +4dBu, your Motu M2's speaker output knob to max, and adjust the final level via the speakers' own volume knobs at the rear. If you want to avoid distortion/clipping while using Windows, there is a separate thread for that in this forum

Sure but I'm using instrument cables, shouldn't I switch them? And isn't that the reason it is clipping? The sounds doesn't even sound that loud to me, it is loud but not piercing if you knw what i mean.

 

[unpluggged]

And isn't that the reason it is clipping?

Probably not.

The sounds doesn't even sound that loud to me, it is loud but not piercing if you knw what i mean.

As I have said before, the manufacturer does not publish SPL figures for this speaker, and this is very suspicious. And it would not surprise me if it is indeed not capable of high SPL levels. It's a compact budget monitor with a rather corner-cutting design, after all, more like a budget passive bookshelf speaker with a built-in amplifier rather than a truly active design..

 

[Exopowk]

Probably not.


As I have said before, the manufacturer does not publish SPL figures for this speaker, and this is very suspicious. And it would not surprise me if it is indeed not capable of high SPL levels. It's a compact budget monitor with a rather corner-cutting design, after all, more like a budget passive bookshelf speaker with a built-in amplifier rather than a truly active design..

Hun, although I'm not sure wether I should set the monitors level to either +4db or -10db. I'm changing my cables to XLR btw, for safety.

 

[unpluggged]

Hun, although I'm not sure wether I should set the monitors level to either +4db or -10db. I'm changing my cables to XLR btw, for safety.

Have another look at post number 334 above.

 

[Exopowk]

Have another look at post number 334 above.

I'm not sure it is clipping but it sounds like it is distorting to say the least.