Sound check suite

Do It Yourself
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I hooked up my phone via USB cable to my DAC in my main system to run these Audio Check tests and learned quite a bit.

Some of the more interesting tests were

  1. Audiometric (Hearing Loss) Test (125-8,000Hz)
  2. Low Frequency Sound Localization and Subwoofer Imaging Test
  3. Aliasing Test
  4. Dynamic Range, Dithering and Noise Shaping
  5. LEDR Imaging Audio Test

The set of Blind Tests were engaging and educational. In those tests, I can reliability detect 0.5dB in volume change, hear differences up to 15kHz, detect at least 5c of pitch variability, and hear 1ms of timing difference. I couldn’t reliably distinguish absolute polarity or, oddly, distinguish 8/16 bit samples.

I’m quite curious about the results in my second system, so I plan to run some of the tests there. I hypothesize that some of my results would change based on performance and characteristics of the system components.

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@vee
Thanks, these on line checks look very interesting. My first appreciation is for the detailed explanations offered by audio check. Still reading, I will run the tests later.

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I’ve supported this effort a couple of times over the years and used some of the tools and sources. Good stuff, thanks for sharing.

Try the MATT test. Online MATT Test | The Listening Test

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One point to note about the Aliasing test.

It won’t be representative through a mobile phone because you have to match the interface rate to the test output rate. i.e. be able to set the USB to 96/192/384/etc to match the file’s rate. Otherwise you’ll hear aliasing where you shouldn’t. On a Mac, you can do this using the MIDI settings app.

Another interesting point is I can hear aliasing at the max Nyquist frequency for a sampling rate. I.e. towards 22.05kHz for 44.1kHz sampling. Both from my DAC and separately from my MacBook speakers as I was trying to isolate cause. Forcing a higher USB interface rate like 48 or 96kHz makes the audible aliasing go away.

I’m not really sure the mechanics of that, but it piqued my interest. It seems to suggest one should playback HiRes files at 2x its sampling rate to ensure any ultra high frequencies present at the Nyquist limit aren’t aliasing back into the audible range.

The files I used to test were generated using REWs Generator. Create a Linear Sweep from 0 to 1/2 the sample rate (i.e. 22.05) and save a file at sample rate / 32-but floating.

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I am having trouble imaging how USB-ing a phone (iphone in my case) can pass low base or highest frequencies to a DSDAC with any accuracy. Please explain, clear my mental cobwebs. I fear that my understanding is challenged.
Chas

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Phones have no issues passing full range frequencies to a DAC. The problem is in configuring the sample rate to match the source file for bitperfect playback.

Many people have plugged small DACs like the Audioquest Dragonfly into phones for bitperfect playback. All you need is an adapter and bitperfect software.

My challenge was because the Audiocheck website is only available through the browser, which is not bitperfect capable.

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If you donate you can download the files.

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Thank you Vee and brett66

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