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what does it cost to measure beyond the limits of audibility?

H

Head_Unit

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I've started asserting that we can measure in time and amplitude far beyond any plausible limit of audibility.* Now I have started wondering: what does that COST?
- Can we suppose an Audio Precision can do the job? Looking up prices, at https://neurochrome.com/pages/measuring-distortion-on-the-cheap it says an APx555b starts around $40k (but shipping shows $12! What a bargain!). Used maybe $6k for an older AP unit, would those do the job?
- That site also touts QuantAsylum QA403 at $600 however as they are looking at distortion it is not obvious to me you can compare waveforms with this thing.
- How about something like Audacity and some kind of sophisticated card for a PC?

*I've also started wondering what IS the time hearing limit...I have forgotten this. Seems 0.5 mS per this:
https://www.aalto.fi/en/news/the-hu...equencies relative to others was also audible.
which leads to https://ieeexplore.ieee.org/document/9450008
There's also this possibly lower threshold https://biology.stackexchange.com/q...tudies,2 ms of temporal summation is required.

As for the amplitude limit...maybe 0.1 dB as a silly low limit? So dependent on many variable. But again nothing that can't be measured inexpensively I should htink?
 
It depends on what exactly you need to measure and how. To measure ultrasonic frequencies beyond audibility is not hard, just get a mic that can capture (say) 24khz moderately well. There you have it, measurement beyond audibility. Apparently there are options down into the single digits of dollars: https://zachpoff.com/resources/cheap-microphones-for-ultrasound/

Differences of accuracy of 0.1dB are easily measurable with any mic that has less self-noise than that, compared to the input signal.

Perception of timing is debatable depending on what type of perception you're talking about, but sampling rate is not the time resolution of a digital recording, that's actually a product of bit depth AND sampling rate, (it took me an embarrassingly long time to understand this) and so time resolution compared to hearing is 'beyond audibility' in pretty much any modern context. A digital recording has a minimum granularity of timing measured in picoseconds.

Anything that can measure distortion down to about -100dB is what I would call beyond the limits of audibility.

Other folks here like @Ageve or @VintageFlanker who have done proper reviews will have a lot more insight on what it takes to do measurements if you don't want to shell out for the Audio Precision gear.
 
For a couple of years, the E1DA Cosmos was the benchmark ADC in the "reasonable price" category. Sadly, it is currently sold out and I think the successor product will take a couple more months to materialize. Currently, the best solution in a similar price range may be a miniDSP Adept. A much cheaper solution could be the Pocket ADC, but I haven't seen an independent test, yet. Then there is the UltraLite mk5, which is also pretty good. So overall, somewhere below 1000 $ for the ADC.
 
Measuring electronic components is easy. All you need is a good sound card and a computer program.
But measuring loudspeakers is way, way more complicated. It's difficult for different types of loudspeakers to even measure close to each other.
 
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