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Does MOTU M2 cut frequencies at 20kHz when used as a DAC?

tomtoo

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Or just has normal hearing... Excuse the pun...

Normal? Thats complicated. Ever tried to hear 26khz? If someone would hear 26khz that would be very,very abnormal. Great,astonishing, superb......add more superlatives.
 
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Trell

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Yes, I know about this never ending argument between people who do hear frequencies higher than 20kHz and those who claim that this is impossible. Note that I am not claiming that I can hear an isolated 26kHz harmonic. The claim is that if one cuts off frequencies 20kHz+ from a lossless music recording then oftentimes the sound quality noticeably drops. There may be several things contributing to this impression, starting with the methods they use to record music. I believe that for most people who use lossless there is no question about "proving this" because we just hear this. Besides, there is a huge market for such people, so I don't think that this is anything like a rare and exceptional ability.

I am really grateful to all of you folks and I will go ahead with ordering M2 relying on your conviction that it probably indeed preserves frequencies up to 26kHz with small distortion.

It is for sure is very uncommon in humans to hear up to 26 kHz, and I'm unsure if anyone has actually proved that they can.

It would be nice if you could answer @FrantzM post #32 above where he asked for more details: https://www.audiosciencereview.com/...-when-used-as-a-dac.35604/page-2#post-1243391
 

tomtoo

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Yes, I know about this never ending argument between people who do hear frequencies higher than 20kHz and those who claim that this is impossible. Note that I am not claiming that I can hear an isolated 26kHz harmonic. The claim is that if one cuts off frequencies 20kHz+ from a lossless music recording then oftentimes the sound quality noticeably drops. There may be several things contributing to this impression, starting with the methods they use to record music. I believe that for most people who use lossless there is no question about "proving this" because we just hear this. Besides, there is a huge market for such people, so I don't think that this is anything like a rare and exceptional ability.

I am really grateful to all of you folks and I will go ahead with ordering M2 relying on your conviction that it probably indeed preserves frequencies up to 26kHz with small distortion.

I not argument, if you can hear this its great. Iam just not sure if its maybe more about the filter you used?
How high you can hear isolated?
 

sarumbear

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I still haven't found a DAC with flat response to 100kHz.
From the specs of RME ADI-2 FAC FS for output:
  • Frequency response @ 384 kHz, -1 dB: 0 Hz – 115 kHz

Now he did. It happened to be the DAC that is the reference for many, hence one expects to be checked first. But why not argue when there’s an opportunity instead of doing research about the point you are arguing?
 

tomtoo

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My hearing was tested on a special machine 8 years ago and the doctor said only that it was "normal". Yes, it maybe something more than just pure harmonics.
What filter you used? Descripe your equipment better pls.
 

tomtoo

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For music listening I used only the simplest equipment available by hand: a Lenovo desktop. However, that must be the latest model of Lenovo with the best available soundbar on it. Unfortunately, I don't have access to it anymore (and this is why I am trying to set up my own audio system now). I do not know the exact model of that Lenovo.

Also, just a few days ago I listened to the same composition on Genelecs which I had listened to both on an LG audio system and on that Lenovo. Well, it sounded differently on the Lenovo, on Genelecs 8010 and on Genelecs 8030: both Genelecs (which were connected to a laptop by a DAC other than M2) clearly outperformed the Lenovo, and all three systems were much better than the LG. I am sure that I would confirm this in a blind test. What I would not be able to tell in a blind test is whether Gen 8010 or Gen 8030 played it better. They sounded different and if I had enough budget I would buy both because sometimes I would prefer the one and sometimes the other.

What kinde of filter you used to cut of the hf?
 
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cestx

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It is for sure is very uncommon in humans to hear up to 26 kHz, and I'm unsure if anyone has actually proved that they can.

It would be nice if you could answer @FrantzM post #32 above where he asked for more details: https://www.audiosciencereview.com/...-when-used-as-a-dac.35604/page-2#post-1243391
I am not the right person to answer this question because I have never arranged a rigorous experiment on the matter. My observation about the importance of past-20kHz frequencies may stem not only from the presence of pure harmonics but from other things too.
 

tomtoo

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Yes. It was really something ad-hoc. I have never intended to prove anything, but was just trying to understand things myself. I did not set up a proper and rigorous experiment.

Ok, then we found the problem. Its not that your hearing goes so high. Lets imagine you have a graphic eq and the slider says 20k. Than you not cut of at 20khz, you lower that complete band. What means you also lower 15 khz what you can hear.
See thats a 20 band graphik eq.
See how it starts to lower at 10k?

I cant hear 20k but for sure i can hear this filter.
 

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sarumbear

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However, this still does not change my conclusion: high frequency filtering oftentimes reduces the sound quality of the recording.
if you define high frequency as 20kHz, I have news for you. Until a few years ago there were almost no recordings that has any signal above 20kHz. Your conclusion is based on what you think, not on fact.
 

tomtoo

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if you define high frequency as 20kHz, I have news for you. Until a few years ago there were almost no recordings that has any signal above 20kHz. Your conclusion is based on what you think, not on fact.

Be nice, he uses a eq without knowledge. He thinks lowering the 22khz band at a geq is the same as a 22khz lpf. I mean that happens often, he lowers the 22khz band, hears a difference and thinks he can hear up to 22khz. ;)
 
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sarumbear

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bennetng

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I didn't read the entire thread but this is my m4 line level loop using trs in and out.
Seems to agree with Amir and another Japanese site's results. The frequency response plots are mostly bottlenecked by the AKM ADC, should be flatter when measured with something like the Cosmos ADC or some of the Cirrus Logic ADC used on other interfaces (e.g. Focusrite).

FYI:
 

JimmyBuckets

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Seems to agree with Amir and another Japanese site's results. The frequency response plots are mostly bottlenecked by the AKM ADC, should be flatter when measured with something like the Cosmos ADC or some of the Cirrus Logic ADC used on other interfaces (e.g. Focusrite).

FYI:
I didn't take pics but my 44.1k, 48k and 88.2 k plots looked similar as well.
 

sarumbear

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If you look close in the pic you can see it but 192k with the largest FFT size of 131K
I'm sorry I missed the greyed parts of the image. Your chart does not go as low as -3dB point hence we do not know the bandwidth value but it should satisfy the OP that his 26kHz value is not a limit for this device.
 

JimmyBuckets

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I am mostly a noob when it comes to measuring electronics. I used 0.5dB scale to show what I consider the usable bandwidth. Also to show the OP he has nothing to worry about. Mine is a v1 so assuming the new layout and chipset measure as good. Has anyone measured original vs something like the v3?
 

sarumbear

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I am mostly a noob when it comes to measuring electronics. I used 0.5dB scale to show what I consider the usable bandwidth. Also to show the OP he has nothing to worry about. Mine is a v1 so assuming the new layout and chipset measure as good. Has anyone measured original vs something like the v3?
What you have done was good and very helpful. FYI, the term bandwidth often is related to the ends of the spectrum where the signal reaches -3dB point. However, you have supplied us enough information that should satisfy the OP.

Thank you.
 
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