Reviewed on: SoundStage! Solo, March 2020

I measured the TWS6 earphones using laboratory-grade equipment: a G.R.A.S. Model 43AG ear/cheek simulator/RA0402 ear simulator with KB5000/KB5001 simulated pinnae, and a Clio 10 FW audio analyzer. For isolation measurements, I used an M-Audio Mobile Pre USB interface and TrueRTA spectrum analyzer software. I used an MEE Audio Connect Bluetooth transmitter to get signals into the earphones. All measurements were made using the small silicone eartips with the medium-size silicone “wings,” as these fit the ear/cheek simulator best. These are “flat” measurements; no diffuse-field or free-field compensation curve was employed. I don’t include a spectral decay chart here because while I was able to get a measurement (which I can’t usually do with true wireless headphones due to latency), it was somewhat idiosyncratic and I can’t be sure the idiosyncrasies aren’t due to the Bluetooth connection. If you’d like to learn more about what our measurements mean, click here.

Frequency response

The above chart shows the TWS6 earphones’ frequency response. I’ve never seen a curve quite like this before. Typically, we’d see a big response bump of about 10dB around 3kHz, but here we see just a tiny, narrow bump of about 3dB. However, there’s a generally rising response above 500Hz, and not much low bass to balance it out, which is likely why these earphones’ sound didn’t have much body.

Impulse response

The impulse response (from which the Clio analyzer derives the frequency response) shows typical latency at 319ms, which is high enough to produce significant lip-sync problems when watching video, but that will depend on the source device.

Frequency response

This chart shows the TWS6 earphones’ right-channel response compared with two other true wireless earphones, as well as the AKG N5005s, which, when used with their reference filters, are the earphones said to best conform to the Harman curve, the response that research shows delivers what most listeners consider the most natural sound. You can see how unusual the TWS6es’ response is; the response of the EarFun Frees is more what I’d consider a “normal” response for relatively inexpensive earphones. The response of the Sennheiser Momentum True Wireless earphones does have certain similarities to the TWS6es’ response, but in my experience, those earphones needed a lot of EQ tweaking to sound good.


Here’s the TWS6es’ total harmonic distortion measured at levels of 90dBA and 99.5dBA, both determined with pink noise. (I wasn’t able to get them to play at 100dBA, my usual measurement standard, with pink noise.) This is a fairly normal result; although the distortion gets up into the 2 to 3% range at 99.5dBA, transducer distortion isn’t all that audible. There is a huge spike in distortion below 23Hz. Because music has almost no content at such a low frequency, I wouldn’t expect this to create audible problems, but I did note bass distortion in my listening.


This chart is produced by playing 85dB SPL pink noise through four speakers plus a subwoofer, “flatlining” the response at the ear/cheek simulator at 85dB, then inserting the earphones and observing the reduction in noise reaching the simulator’s internal microphone. As you can see, the TWS6es’ noise isolation is, like that of some of the best true wireless earphones, excellent if you get a good fit. It’s comparable with what I measured from the Amazon Echo Buds -- and those have active noise canceling!

. . . Brent Butterworth