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Is the MOTU M2 enough to drive the ATH R70x?

zphere

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Hello, I just want preface this post by saying that I am a complete newbie with anything audio and realize my initial research may have not been extensive enough. I just bought a M2 and the R70x ( have only received the M2, still waiting on the R70x) but have come to the realization that the M2 may not have enough power to drive the R70x.

I did make a reddit post before this in r/headphones and was told that M2 should be able to drive them but that something like the FIIO K5 would be better and more efficient, however, I'm just looking for more concrete confirmation.

I did look at the review for the M2 on this website and see that the M2 provides 22 mW @ 300 Ohm load, I can't figure out the conversion to the R70x's 470 Ohm / 99 db/mW Sensitivity.

I essentially just want to know if the M2 would be enough to drive the R70x, or if there is a better alternative. I will say that I would ultimately prefer an audio interface like the M2 over a dedicated amp like the K5 as I want to get an XLR mic and have a MIDI keyboard. If you think that the M2 isn't enough, what audio interface in the 200-300 range would be better?

Any recommendations or responses are much appreciated :)
 

twsecrest

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Plug the ATH-R70X into the Motu M2, see if it drives it.
If not, then connect an external headphone amplifier to the M2's line-output (RCA) jacks.
 

staticV3

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Hi @zphere! Welcome to ASR.

The best insight into the M2's output capabilities comes from Julian Krause's measurements over on his YouTube channel:
Screenshot_20230722-000807.jpg

If you take his numbers, convert them to Vrms, and do a curve fit on them, then it's possible to predict the M2's max output voltage with the R70x as load:
Screenshot_20230722-001700.jpg

2.87Vrms, combined with the R70x's sensitivity which Amir measured at 104dB/Vrms, leaves you with a Peak SPL of 113dB, which is very loud indeed.
94+20*log10(1/0.318)+20*log10(2.8716)≈113.11

Just for a point of reference, my usual listening volume is roughly 80dB SPL Peak, which translates to 10% of the volume that the M2+R70x is capable of.
 
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zphere

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Hi @zphere! Welcome to ASR.

The best insight into the M2's output capabilities comes from Julian Krause's measurements over on his YouTube channel:
View attachment 300633

If you take his numbers, convert them to Vrms, and do a curve fit on them, then it's possible to predict the M2's max output voltage with the R70x as load:
View attachment 300634

2.87Vrms, combined with the R70x's sensitivity which Amir measured at 104dB/Vrms, leaves you with a Peak SPL of 113dB, which is very loud indeed.
94+20*log10(1/0.318)+20*log10(2.8716)≈113.11

Just for a point of reference, my usual listening volume is roughly 80dB SPL Peak, which translates to 10% of the volume that the M2+R70x is capable of.
woah, thank you so much! This was really informative. I guess in that case I will stick with the M2 :)
 
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