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Motu M4 Audio Interface Review

retroflex

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Quite curious - which graph or statement shows this? Always been confused on the gain level you should set for DACs or other upstream equipment.
You can see it on the plot with description "Unfortunately the IMD test relative to level [...]". The line for the Motu M4 keeps going down; compare that to the Razer Adapter line which has a lowest spot at around -15 dBFS (decibels relative to the full output scale). The plot only shows intermodulation distortion, but one would expect other kinds of distortion and SINAD to follow the same trend.

When Amir says the nominal voltage output is 5.2V - is that at the max volume? Since the SINAD tests run at output = 5.2V we should expect full volume doesn’t do any distortion.
He says that 5.2 V(rms) is more than the nominal balanced output of a DAC, which he considers to be 4 V(rms) if I'm not mistaken (I don't know if there is any official standard here). The review doesn't say that this is the maximum output, but I'm pretty sure it is. It's certainly a bit confusing that the manual claims that the maximum output is lower than this.

I read the manual but didn’t understand dBu to volts conversion. Seems like standard thing in audio to represent volts in dBu?
Just saying "volts" doesn't mean much when talking about an audio signal, since it's not clear if you're talking about peak voltage, peak-to-peak voltage, root-mean-square voltage, or something else. Similarly, talking about "decibels" on its own is meaningless, a decibel is always relative to some absolute quantity. Combine those two factors, and throw in some history, and you get the absolute mess that is the various types of decibel units used to describe sound.
 

robertzsun

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Thanks for the great info! I come from an EE background and it’s been tough to reconcile the audio terminology and techniques to classic analog design or signal processing - just have some stupid burning questions that are relatively bizarre.
 

CtheArgie

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I am sorry if I missed this but: If I want to connect an unbalanced RCA to the line input of a M4, which is the correct adaptor to use?
1. Female RCA-Male TS.
2. Female RCA-Male TRS.
3. Female RCA-XLR.
Thanks....
 

Lambda

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1. Female RCA-Male TS.
yes. this.

Just saying "volts" doesn't mean much when talking about an audio signal, since it's not clear if you're talking about peak voltage, peak-to-peak voltage, root-mean-square voltage,
root-mean-square voltage is actually equally unclear if you don't define the waveform at the same time.
 

Cadence

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The M2 / M4 were released in 2019. Could Motu release entirely new models of these entry-level interfaces, or do the new revisions practically exclude such a possibility?
 

Trell

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The M2 / M4 were released in 2019. Could Motu release entirely new models of these entry-level interfaces, or do the new revisions practically exclude such a possibility?

I would say unlikely, at least for the short term.
 

phoenixsong

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Probably depends on how much they are affected by the releases of the Arturia Minifuse, Universal Audio Volt and Audient id14Mkii interfaces since then
 

mightycicadalord

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Oh man, that audient id14mkii looks like a killer deal, is anyone else doing adat pre expansion for $300?

The volt, minifuse, and audient don't have real meters though, I don't think I can go back to having crappy segment LED metering.
 

Buckster

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noticed earlier another firmware update for the M4 (version 2 of it I think)

was dated mid-Jan- mine now states Firmware version 2.02

no idea of changes but all seems good so far
 

jtwrace

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If anyone needs a 3d printed shelf for their M4, here ya go.


1643916504003.png
 

Vict0r

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noticed earlier another firmware update for the M4 (version 2 of it I think)

was dated mid-Jan- mine now states Firmware version 2.02

no idea of changes but all seems good so far

I downloaded the M4 2022 firmware updater, after reading your post, but mine says it is already up to date. I'm at 1.0.2. Weird.
 

Trell

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I downloaded the M4 2022 firmware updater, after reading your post, but mine says it is already up to date. I'm at 1.0.2. Weird.

That means you have the interface before the change to ESS whose firmware versions starts at 2.

Edit: There is a new revision of the interface with firmware version 2.x. Forgot what changed.
 
Last edited:

Trell

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You mean change to different ESS? I think the m series has been ESS since version 1.

Yes, I must have recalled incorrectly. There is a new revision of the interface so that is the reason of the new firmware version.
 

Archon43

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Oh man, that audient id14mkii looks like a killer deal, is anyone else doing adat pre expansion for $300?

The volt, minifuse, and audient don't have real meters though, I don't think I can go back to having crappy segment LED metering.
I just had, and sold, the Audient ID14 MK2, to be honest I was not terribly impressed. I just purchased the MOTU M4 and as far as sound quality, flexibility, and looks, the MOTU M4 blows the Audient out of the water. Not to mention the very useful front metering.

This sounds as good if not better than my Topping E50 DAC with an iFI linear power supply, in fact I like it better as it sounds a bit more analog and not as clinical sounding.

The M4 has consumer and pro audio outputs, MIDI in and out, two active preamps, two passive preamps (allows you to hook up an external device such as a mixer, DAC to compare sound quality, or outboard preamps).

MOTU really hit a homerun with this, the sound quality is better than my former Audient ID14 MK2, Focusrite 18i20 3rd gen, M-Audio AIR 192/4 which I am returning after driver issues (M-Audio does not like my Ryzen system at all) and getting this, and Audient Evo 8.

I also do recording with my Rode PodMic and it drives my mic (known to be power hungry) with ease with no need for a cloudlifter. There is a noticeable sound quality step up from both the Audients as well as the Focusrite and M-Audio on my recordings. This is definitely a keeper, I would only upgrade if MOTU came up with an upgrade for it or if I needed more inputs.
 

Cadence

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I just had, and sold, the Audient ID14 MK2, to be honest I was not terribly impressed. I just purchased the MOTU M4 and as far as sound quality, flexibility, and looks, the MOTU M4 blows the Audient out of the water. Not to mention the very useful front metering.

This sounds as good if not better than my Topping E50 DAC with an iFI linear power supply, in fact I like it better as it sounds a bit more analog and not as clinical sounding.

The M4 has consumer and pro audio outputs, MIDI in and out, two active preamps, two passive preamps (allows you to hook up an external device such as a mixer, DAC to compare sound quality, or outboard preamps).

MOTU really hit a homerun with this, the sound quality is better than my former Audient ID14 MK2, Focusrite 18i20 3rd gen, M-Audio AIR 192/4 which I am returning after driver issues (M-Audio does not like my Ryzen system at all) and getting this, and Audient Evo 8.

I also do recording with my Rode PodMic and it drives my mic (known to be power hungry) with ease with no need for a cloudlifter. There is a noticeable sound quality step up from both the Audients as well as the Focusrite and M-Audio on my recordings. This is definitely a keeper, I would only upgrade if MOTU came up with an upgrade for it or if I needed more inputs.
Great information, thank you!

Do you have any opinion on the SSL2, on the cheaper end, and the new Focusrite Clarett+, on the more expensive end, when compared with the Motu M4?
 

Archon43

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Great information, thank you!

Do you have any opinion on the SSL2, on the cheaper end, and the new Focusrite Clarett+, on the more expensive end, when compared with the Motu M4?
I updated the post to have even more information on there, thank you as well!

I have heard nothing but good things about the SSL and SSL+, and I considered the SSL+ before getting this. While I have not heard the SSL, I think you really cannot do wrong with either. The MOTU M4 is more flexible and has a more appealing format to me, so that is why I chose it. The SSL and SSL is missing features (two extra inputs which are not affected by the internal preamps, metering built in).

The Clarett+ is likely going to be a step up in preamp quality, but I have doubts it would sound better than the M4 as far as the audio output. I can say for sound quality, the MOTU M4 easily beats the Focusrite 18i20 3rd gen. I owned the original Clarett and it sounded great, but I had a totally different audio setup before, so I could not apples to oranges compare the sound to the M4. The M4 has a DAC used in high end audio interfaces, that is why is sounds good and measures really well.

If you do not have a seperate DAC and the features appeal to you, the MOTU M4 sounds awesome and has a lot of features. For preamp quality, the SSL with the 4K mode may better the M4, but not sound as good for the audio output. The Clarett+ is likely the best all aorund, but ask yourself if the asking price is worth it.

I hope this helps.
 

Cadence

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I updated the post to have even more information on there, thank you as well!

I have heard nothing but good things about the SSL and SSL+, and I considered the SSL+ before getting this. While I have not heard the SSL, I think you really cannot do wrong with either. The MOTU M4 is more flexible and has a more appealing format to me, so that is why I chose it. The SSL and SSL is missing features (two extra inputs which are not affected by the internal preamps, metering built in).

The Clarett+ is likely going to be a step up in preamp quality, but I have doubts it would sound better than the M4 as far as the audio output. I can say for sound quality, the MOTU M4 easily beats the Focusrite 18i20 3rd gen. I owned the original Clarett and it sounded great, but I had a totally different audio setup before, so I could not apples to oranges compare the sound to the M4. The M4 has a DAC used in high end audio interfaces, that is why is sounds good and measures really well.

If you do not have a seperate DAC and the features appeal to you, the MOTU M4 sounds awesome and has a lot of features. For preamp quality, the SSL with the 4K mode may better the M4, but not sound as good for the audio output. The Clarett+ is likely the best all aorund, but ask yourself if the asking price is worth it.

I hope this helps.
Thank you a lot again!

I asked about the SSL2 and Clarett+ because of my indecision between the M4, ID14 MKII and Clarett+ 2Pre and the recent discovery of a like-new used SSL2 for a low price. I guess the ID14 MKII can be excluded. The Clarett+ 2Pre features optical input and probably a better headphone output, but loses two line inputs on the back and has a considerably higher price; it doesn't seem to be that different from the previous USB-C Clarett, so the M4 sound quality for both recording and listening could match it; the Clarett+ 4Pre can be the model for a better choice, but the price bracket is very different and the interface may then compete with something like the UltraLite MK5, not the M4.

After many evaluations, I believe the M4 is the right option for me. The SSL2 has less features and worse outputs, as mentioned, but the low price of this specific discovery may make buying it as a second interface, alongside the M4, a nice idea. I do not particularly care about the 4K emulation, but I nonetheless read positive comments on its recording quality even without colouring the sound.
 
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