Best way to go about measuring Bluetooth MMCX Headphone Adapter for IEMs?

[Sythrix]

Hello, I have recently ordered the MEE Audio BTX1. It has not arrived yet. I plan to use it for running.

It features aptX and AAC protocols for ~CD quality music~

There are no measurements or given information whatsoever on the performance of the amplifier or DAC for this, or really any of the bluetooth headset adapters. It's as though people don't care about technicalities the second you make a DAC/Amp look like a headset (look at any standalone bluetooth amp or adapter with a 3.5mm plug and it will give measurements and rated performance.)

Anyways, I want to know the best way (if it's even feasible to do) to actually measure anything off of this thing. Again, it's bluetooth, so I am unsure if there's anything that would be able to send an appropriate signal to it, in order to facilitate measurement. I found these MMCX to 3.5mm adapters, so maybe it would be possible to adapt to a usable connection. I have an ASUS STX II sound card with a fairly decent ADC (1/4"), but no professional audio equipment.

If it's a lost cause, then I guess I'll just let it go. However, I figured if anyone knew of a way to do it, it would be here.

 

[amirm]

Wonder if it shows up as a sound device on PC/Mac. If it does, then you can play files and measure the results with your sound card. Compression artifacts of course will get in the way of any critical measurements.

 

[andreasmaaan]

I've always found that with bluetooth speakers the transmission lag confounds my measurement software (HOLM).

Not sure if this would apply to the kind of measurement you want to do / different measurement software.

 

[Sythrix]

Wonder if it shows up as a sound device on PC/Mac. If it does, then you can play files and measure the results with your sound card. Compression artifacts of course will get in the way of any critical measurements.

Which files and what software should I use to do the measurement? Also, would any setting (like higher bitrate) mitigate the compression artifacts? Thanks!

I've always found that with bluetooth speakers the transmission lag confounds my measurement software (HOLM).

Not sure if this would apply to the kind of measurement you want to do / different measurement software.

Honestly I don't know yet. Don't have any software. I just wanted to get a basic idea of what I'm looking at/what I'm in for, but if lag is going to be an issue, it might not work. Don't really want to spend a bunch of money if it's not practical.

 

[andreasmaaan]

Yeh, I've only ever tried to measure anything bluetooth with one piece of software, and because in that case I was able to use a cable connection anyway, I didn't persevere for long to see if there was a way to work around it. Perhaps others have more experience trying to do this and can give more certain advice...

 

[Blumlein 88]

You can do some basic stuff with Audicity. Make some test signals. Play them over the device, and record from your Asus sound card using Audacity to record. And then some basic measurements can be done on the recorded file with Audacity which is free. It is not optimum or automatic, but it works.

Another more automated approach is the free version of RMAA. I dont' know how it would perform over the bluetooth with the lag and such. Or the compression artifacts.

A bit more involved would be using REW, which can send an acoustic pulse to set time for any delay involved. Room EQ Wizard is a slightly more involved to learn, but not too bad. Again I'm not sure how much the APtX would monkey with things. Surely someone has measured that before.

 

[Blumlein 88]

JA at Stereophile has measured at least three similar devices using AptX.

https://www.stereophile.com/content/arcam-rblink-bluetooth-da-processor-measurements

 

[Sythrix]

JA at Stereophile has measured at least three similar devices using AptX.

https://www.stereophile.com/content/arcam-rblink-bluetooth-da-processor-measurements

Interesting article and thanks for the suggestions.

I don't know if I'm interpreting everything correctly, but it seems that aptX can significantly alter the measurement landscape, regardless of perceived sound quality. I'm not so sure I want to attempt measurement anymore, given that my already amateur wading might turn into full on drowning trying to make any sense out of the codec/compression compromised signal.

Will have determine if I want to order the adapters and try to figure it out.