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Apollo x16claims -129dB thd+N

helloworld

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#1
http://media.uaudio.com/support/manuals/v961-3m2bV/Apollo x16 Hardware Manual.pdf#page27
It has 133 dB dynamic range and -129dB thd+N which I think there must be somthing wrong here. Ess9038pro ony has -122dB thd +N and I dont think Apx555 could test such a low thd +N. I guess the real number should be -119dB, but still very amazing. Apogee Symphony io 2x6 SE has 131 Dynamic range and -118dB thd+N which they use 9028pro. Dont know if they have the ESS hump
 

Blumlein 88

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#2
Yes, those specs are difficult to believe. I'd like to know all the fine details under which they obtained such numbers. My guess is some misdirection.
 

helloworld

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#3
In page 27, they claim and I quote:
All specifications are typical performance unless otherwise noted. Tested with the Audio Precision APx555 Audio Analyzer under the following conditions: 48 kHz internal sample rate, 24-bit sample depth, 20 kHz measurement bandwidth, +24 dBu headroom, balanced output, and internal clock.
 

Blumlein 88

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#4
In page 27, they claim and I quote:
All specifications are typical performance unless otherwise noted. Tested with the Audio Precision APx555 Audio Analyzer under the following conditions: 48 kHz internal sample rate, 24-bit sample depth, 20 kHz measurement bandwidth, +24 dBu headroom, balanced output, and internal clock.
Yes, but there are other details worth knowing. I would feel much better if they had the above note along with saying they followed AES17 testing standards. For instance I suspect on the Monitor out specs they are using max level output with noise from lower Monitor level output to "expand" the dynamic range they can quote. But I don't know for sure. It seems so good as to be suspect.
 

KSTR

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#7
Some of the best studio DACs reach dynamic range values like that. For example, the Stage-Tec XDA+ specs 131dB(A) / 129dB(RMS), with 0dBFS=+24dBu output level. It's transformer-coupled, therefore THD+N is "only" 0.02% worst-case. So there is a chance others might get down there, too.
 

Krunok

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#8
Some of the best studio DACs reach dynamic range values like that. For example, the Stage-Tec XDA+ specs 131dB(A) / 129dB(RMS), with 0dBFS=+24dBu output level. It's transformer-coupled, therefore THD+N is "only" 0.02% worst-case. So there is a chance others might get down there, too.
Sure they do, but has that been confirmed by independent measurements?
 

svart-hvitt

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#9

March Audio

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#10
Some of the best studio DACs reach dynamic range values like that. For example, the Stage-Tec XDA+ specs 131dB(A) / 129dB(RMS), with 0dBFS=+24dBu output level. It's transformer-coupled, therefore THD+N is "only" 0.02% worst-case. So there is a chance others might get down there, too.
0.02% is about 74dB, thats horrible.

Their data sheets state 0.0006% THD + N which is about 106dB. Im not convinced dynamic range is that useful a measurement.

Also make sure if its AES17 and that it doesn't have digital zero mute engaged.
 
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helloworld

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#11
Actually even those spec numbers these pro audio makers offered are a little bit higher, for example, 5dB higher, consider their price, the AD part, the software, a lot of channels, some come with the mic preamp, still a worth to buy. Hopefully we can get these pro products reviewed in the future. At least they are not overpriced like those hifi products.
 

March Audio

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#12
Actually even those spec numbers these pro audio makers offered are a little bit higher, for example, 5dB higher, consider their price, the AD part, the software, a lot of channels, some come with the mic preamp, still a worth to buy. Hopefully we can get these pro products reviewed in the future. At least they are not overpriced like those hifi products.
Oh I agree, I use a Motu 8A, its performance v price is fantastic
 

amirm

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#13
Being lazy and not thinking it thru, could your AP unit measure this to these levels? @amirm
They don't specify the bandwidth but here is AES-17 dynamic range for 90 kHz (analog out, analog in):

1536339631251.png


Above is with 4 volt output. Other values may generate better results but probably not much better.
 

amirm

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#14
And THD+N with a-weighting at 5 volt level:

1536339852613.png


So what they are listing are the edge of the analyzer performance. We would need to use FFT to determine true performance.
 

helloworld

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#16
it's a typo, that's all
They reply to me and I quote:”Our information is not public what converters we used from my knowledge. I'm afraid this information is not available to the public. The information we have available to the public is what you seemed to already quote. Since no more information can be provided about testing, I will go ahead and close this ticket. ” So It’s not a typo. They seems to hit the limit of the analyzer with a crazy number -129dB a weighted. I will be surprised to see what’ the unweighted number, it will be at least -120db to get that high A-weighted number.
 

Theo

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#17
As a technical subject and chasing fake marketing, this is a good topic. Sounds like (IMHO) they are quoting the maximum dynamic range measurement possible indeed... But, how important is this in a day to day use in a professional studio, say compared with an Apogee or Motu interface ?
 

Blumlein 88

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#18
Yes, when you look at microphone self noise, and ambient noise in the area being recorded (even in a quiet treated studio), and realize any gain applied by the microphone pre amplifies this noise along with the signal I'm not sure any recordings can really use up 16 bits. The basic output impedance of most mics will limit you via thermal noise to a theoretical minimum of -133 dbV of noise. About the best any circuitry manages is to get to -129 or 130 dbV on that. You normally will use at least 30 db of gain on that which puts you at roughly -100 dbV. That is before adding microphone self noise or ambient noise. All these are unweighted values.
 

helloworld

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#19
There is one review of apollo x6 in a Chinese website. They did a teardown to look at the dac chip and it’s 2x ess 9016. This chip has a theoretically -110dB thd+n and 124db DNR while this apollo x6 claims 129dB DNR and -118dB thd+n.
I guess the flagship apollo x16 probably only use ess9018.
 
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