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Motu M2 Review (Audio Interface)

Music1969

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#61
Could you please tell what crossover and EQ? Is it a PC-only as a source? How do you control the volume? Thanks.
Hi, yes the source is PC only.

For music playback, I can use Roon to control the volume, just using my iPad while sitting in listening position.

For movies on the PC (Netflix etc) playing to TV and Projector, I can control volume using the convolver program - using a bluetooth combination keyboard+mouse from listening position to adjust easily.

Usually for a movie you set to one volume and don't need to touch for 2 hours but it's easy to change.
 

DDF

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#63
John Siau from Benchmark seems to disagree and states that the imd is common mode and removable if a differential amp is added at the dac chip o/p:
https://www.audiosciencereview.com/...nts-of-benchmark-dac3.3545/page-16#post-90519
What he said is almost completely false from what I actually measured...the noise of DAC3 is way too high to reveal the imd hump of 9038pro/9028pro...Ben from Soncoz, IMD hump can be fixed by changing values of feedback RC of the I/V circuit
I think you owe John Siau an apology. From Amir's tests, the Benchmark DAC3 is the quietest of the bunch and with no IMD hump. From an engineering perspective, his fix is also reliable.

Motu M2 using ESS 9016 (if same as M4)
1612112337068.png


Soncoz, Ben's I/V fix from here with the lower power converter ES9038Q2M
1612112601431.png


Benchmark DAC3 from here using 9028PRO
1612112755099.png


Ben's fix seems to resolve one cause of the IMD hump, but TBD if it works for other ESS chip variants, and it leaves a bit of (inconsequential) performance on the table.

I checked the data sheets, and all these DAC chips support differential outputs. John's fix directly nulls all common mode error at the output, a more all-encompassing fix, as it removes all causes of common mode noise and distortion for all the chip variants.
 

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JohnYang1997

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#64
I think you owe John Siau an apology. From Amir's tests, the Benchmark DAC3 is the quietest of the bunch and with no IMD hump. From an engineering perspective, his fix is also reliable.

Motu M2 using ESS 9016 (if same as M4)
View attachment 109659

Soncoz, Ben's I/V fix from here with the lower power converter ES9038Q2M
View attachment 109663

Benchmark DAC3 from here using 9028PRO
View attachment 109664

Ben's fix seems to resolve one cause of the IMD hump, but TBD if it works for other ESS chip variants, and it leaves a bit of (inconsequential) performance on the table.

I checked the data sheets, and all these DAC chips support differential outputs. John's fix directly nulls all common mode error at the output, a more all-encompassing fix, as it removes all causes of common mode noise and distortion for all the chip variants.
Bruh. Soncoz has 9038Q2M instead of 9028pro. If you want to, please compare to okto dac8 stereo. 9028pro is roughly 8*9038q2m performance and 9038pro is roughly 16x. DAC3 was ok for the time but damn it underachieved with performance of only (not even) single 9038q2m.
I wasn't saying DAC3 has horrible IMD Hump, but it has high enough noise to cover quite a lot of it. Surely many other designs are much worse. But that's not what I was saying. 9028pro inherently is a better behaved dac than 9038q2m to begin with probably even more so than 9038pro in some cases just with a bit higher noise floor in extreme condition.

And 9016 in M2 is a completely different issue to begin with as I described earlier. Also it is supposed to have much worse performance to begin with but in the end they got quite similar?(minus the hump part).

Also the point John Siau was making is that the CAUSE of the hump is the lack of differential amplifier which is disproved automatically with designs that have imd hump on balanced output. But in a good design there should be no hump either half of the output.
 
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JohnYang1997

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#65
I think you owe John Siau an apology. From Amir's tests, the Benchmark DAC3 is the quietest of the bunch and with no IMD hump. From an engineering perspective, his fix is also reliable.

Motu M2 using ESS 9016 (if same as M4)
View attachment 109659

Soncoz, Ben's I/V fix from here with the lower power converter ES9038Q2M
View attachment 109663

Benchmark DAC3 from here using 9028PRO
View attachment 109664

Ben's fix seems to resolve one cause of the IMD hump, but TBD if it works for other ESS chip variants, and it leaves a bit of (inconsequential) performance on the table.

I checked the data sheets, and all these DAC chips support differential outputs. John's fix directly nulls all common mode error at the output, a more all-encompassing fix, as it removes all causes of common mode noise and distortion for all the chip variants.
And by the way you got the wrong graph for the fixed 9038q2m I suppose.
1213-1448 (1).png
 
OP
amirm

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Thread Starter #66
@amirm Is there any possibility of reviewing SSL 2+ ?
Thanks
I don't have one to test unfortunately. Maybe a few of you could get together to fund it? It is $220 or so.
 

DDF

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#67
And by the way you got the wrong graph for the fixed 9038q2m I suppose.
You're right, I grabbed a shot of his initial solution, he did get it down further, thanks for correcting.

Bruh. Soncoz has 9038Q2M instead of 9028pro....
You were comparing Soncoz to Bookmark, it was me (not you) that pointed out you can't do that as they use different dacs. My point to show the DACs IMD measures was to point out that the DAC3 has no trace of the hump while simultaneously having commendably low noise. Your "way too high" noise comment implies something very different.

Also the point John Siau was making is that the CAUSE of the hump is the lack of differential amplifier...
Here's exactly what John said, from my earlier link:

"This IMD (and THD) is a direct result of omitting a differential amplifier after the output of the chip" and,

1612134499112.png


John's an engineer and knows better, he wasn't saying the diff amp's absence causes the distortion, but the solution is to use one to cancel common mode.

It's not a good look to disparage a competitor using misleading statements. I get it that you're incentivized to defend a market position, but I'm not incentivized to support that. I'm out.
 

JohnYang1997

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#68
You're right, I grabbed a shot of his initial solution, he did get it down further, thanks for correcting.



You were comparing Soncoz to Bookmark, it was me (not you) that pointed out you can't do that as they use different dacs. My point to show the DACs IMD measures was to point out that the DAC3 has no trace of the hump while simultaneously having commendably low noise. Your "way too high" noise comment implies something very different.



Here's exactly what John said, from my earlier link:

"This IMD (and THD) is a direct result of omitting a differential amplifier after the output of the chip" and,

View attachment 109744

John's an engineer and knows better, he wasn't saying the diff amp's absence causes the distortion, but the solution is to use one to cancel common mode.

It's not a good look to disparage a competitor using misleading statements. I get it that you're incentivized to defend a market position, but I'm not incentivized to support that. I'm out.
I didn't compare SGD-1 to DAC3 like at all. I said Ben from Soncoz showed the IMD is present with the use of differential amplifier as well as balanced output. I never said anything about sgd1 or its performance.

The mechanism of IMD applies to all 9028q2m 9038q2m 9028pro 9038pro but not 9018s 9018k2m 9016.

The noise performance is obviously different from 9028pro to 9038q2m. That's the difference.

If the noise of DAC3 is as low as okto dac8 stereo, the IMD will be apparent. There was a bit of it already showing at -20db.

"IMD is a direct result of omitting differential amplifier" Isn't it exactly the same as the The lack of the differential amplifier caused the IMD hump??? What? He also said using transformer coupled input AP doesn't show the IMD which is also not the case.

I'm also an engineer. D10s rivals/ outperforms DAC3 with only 2V and single ended output. Ever thought of that?
 

JohnYang1997

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#69
I'm not trying to argue. I am simply demonstrating that the understanding at that time was pretty much completely incorrect.
If you look back you'd see that I was simply explaining the mechanism of the hump is different between 901x and 903x.
You then showing John Siau's comments a couple of years ago, discussing that what I said is probably wrong.
I then explain to you how the understanding of the matter was almost completely wrong and how we can do better.
I think both of us have illustrated what we are after so can we move on? :D
 

infinitesymphony

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#72
It has the same look as the M4. But M2 and M4 were a departure imo.
https://duckduckgo.com/?q=motu+mark+of+the+unicorn&iar=images
Oh, I don't know... I was using a MOTU 828mkII in the mid-2000s and I think the design language has been consistent since then -- rounded edges, small knobs, channel meters. You could always leave the rack ears off for desktop use, and that's how I used it. One of the only differences is the use of analog pots on the M2 and M4, because the higher-end models use digital controls for everything now (ex. MOTU 624).

MOTU 828mkII (2003)

 
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#76
Nice. Is that a Fluance table ?
That's correct. It's Fluance RT82 but I upgraded acrylic platter as well as cartridge. It's a Super RT82 now :)

What do you like better about the M2 vs. 2i2? What gen 2i2? Curious to hear your impressions.
Hey thanks for asking. I tried Gen3 2i2 and you could hear some samples (with air mode OFF)

From sound perspective, Gen3 2i2 is brighter on higher end, while m2 is warmer. Gen3 is sharp and smooth, but I do feel it's just not that natural compared to m2 which is more balanced (some may prefer that air or sharpness from Gen3 2i2). Moreover, m2 wins on Micro-dynamics, a bit. Both sounds very good to my ear, while both lack some bass if compared to direct output.
 

infinitesymphony

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#77
That's correct. It's Fluance RT82 but I upgraded acrylic platter as well as cartridge. It's a Super RT82 now :)


Hey thanks for asking. I tried Gen3 2i2 and you could hear some samples (with air mode OFF)

From sound perspective, Gen3 2i2 is brighter on higher end, while m2 is warmer. Gen3 is sharp and smooth, but I do feel it's just not that natural compared to m2 which is more balanced (some may prefer that air or sharpness from Gen3 2i2). Moreover, m2 wins on Micro-dynamics, a bit. Both sounds very good to my ear, while both lack some bass if compared to direct output.
Thanks for that. Amir did notice that using the Focusrite 2i2 Gen 3's TRS inputs resulted in 10 dB lower SINAD performance than using XLR, so it may have a disadvantage there. I wonder if the frequency response over TRS might also be affected? Not sure if the FR measurement in the review includes both or XLR only.

As it stands the 2i2 Gen 3 seems to have the flatter ADC FR of the two:

Focusrite Scarlett 2i2 Gen 3 ADC FR


MOTU M2 ADC FR
 
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#78
Thanks for that. Amir did notice that using the Focusrite 2i2 Gen 3's TRS inputs resulted in 10 dB lower SINAD performance than using XLR, so it may have a disadvantage there. I wonder if the frequency response over TRS might also be affected? Not sure if the FR measurement in the review includes both or XLR only.

As it stands the 2i2 Gen 3 seems to have the flatter ADC FR of the two:

Focusrite Scarlett 2i2 Gen 3 ADC FR


MOTU M2 ADC FR
Thanks! FR seems more flat for Focusrite.
 

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