Limitations of technology, or poor fitting?

Agreed that you should get the hearing aids tested. Ideally bring a shaker into your audiologist’s office and demonstrate. If that’s not possible, that’s one of the downsides of DIY.

Try searching for warble on this forum.
In particular the music people complain about warbling at certain frequencies.

Most have been able to eliminate this warble by minimizing the hearing aids setting for noise, wind, echo ECT.

Another search that might help is music program.

Lots of information on this is this forum. Detailed tuning can be found in the DIY area of this forum.

I managed to capture the input spectrum of the shaker using the Inspire X software.

Interestingly, it suggests that the spectrum exceeds the 8kHz bandwidth that the HAs can manage. I am hypothesizing that perhaps as the sound gets louder, the high frequency components get increasingly clipped resulting in the unpleasant transition from a gentle rattle to a crude crunching sound. This issue was magnified that due to my reverse slope HL, I was applying more gain to the lower frequencies than usual.

To investigate, I cut off all amplification to the low frequency bands and true enough, the shaker sounds less “crunchy” now. Now begs the question: when will HAs come with a wider bandwidth, or at least a mode with wide bandwidth if the user needs it (I assume power consumption is the main limiting factor)? I’m sure what I encountered isn’t a corner case as many musical instruments extend beyond 8K.

If they’re barely a month old, is returning them an option? Ah, you’re from China, maybe not.

From your picture, the difference in sound picked up by the microphones of the left and right hearing aids at the same moment is so obvious that the problem may be in the microphones.
The best thing to do is to send the hearing aid to the starkey factory for service.
In addition, you can check the microphone for moisture or dust buildup.
If your hearing aid are BTEs or RICs, you can swap the left and right hearing aids and reprogram them to see if the sound will be different.

Very interesting, but a really tough problem, given the severe space and power limitations in an HA. In the old days, to process audio up to 8 kHz, an A/D converter might sample at e.g. 20 kHz, preceded by an analog LPF with an accurate passband up to 8 kHz and sufficient attenuation in the 12+ kHz stopband. But that required several op-amps, accurate capacitor values, etc., not practical in an HA. To reduce costs, the modern solution is to sample at e.g. 320 kHz, with a trivial RC filter on the input. The result is then downsampled to 20 kHz with a proper LPF in the digital domain. That may also be currently impractical in an HA, as the computational load may exceed the power budget. I’m not surprised that the manufacturers skimp in this area.

@user444 said:

I did a quick verification by covering the mics with a napkin and the artifacts are gone!

Dr. Marshall Chasin, a leading AuD of fitting HAs for musicians strongly suggests using scotch tape over the mics to lower the input headroom.
You can google him, and get some excellent advice on programming HAs for music.

Hello user444. This is a very interesting thread. Spectrograms, too!
Cursed/blessed with hearing developed in a BBC job, and having a love of music, hearing aids for later life high-end droop have introduced new challenges. I have learned that individual audiologists may or may not be music-aware, and I have to say that seems to apply to some manufacturers as well.

First - that shake/rattle phenomenon. For several years, my obsolete Phonak Naidas delivered pretty good speech and ‘live’ music, once all fancy processing had been turned off, apart from high end boost and ‘comfort’ compression.

Then, I was fitted with Signia something-or-others. Dreadful, painful clicks on transient sounds - including elements of speech - simply because the compression was too slow acting. In my day-work I would regard such a thing as mis-design. I improvised a test-rig, and showed the trace of spikes to my audiologist, who to her great credit made contact with the manufacturer.

Now, she’s fitted me with later Phonaks, the M70. She took care, let me try music, extended the lows so I could even hear down to 40Hz, bottom E. Wonderful, but earmoulds had to be replaced - and since then the settings have evidently changed: warble at 2,100 Hz, low-beats if you play that C with an E, ‘clogged’ and phasey orchestral sounds, fade-aways if the music is quiet…
So, yes, fitting is crucial.

As for microphones. It would be surprising if they were culprits. A basic condenser capsule can be bought for £1.50. These will deliver excellent fidelity, and don’t overload until sound level is very high. No doubt hearing aid miniatures do cost more, but surely not worth cheapening?

Most of the cost of an aid is not actually in the box, but in the services and research surrounding it! The very fact that those iPods pro work so well at a fraction of typical HA costs says a lot.

That’s an ingenious diagnosis, to use a napkin over the mic. Similar here: I have a pad over my hi-fi tweeters so they give out less of what I cannot hear anyway, and put less stress on the hearing aid. Yes, indeed, there should be early-stage filtering. Among the handful of really smart audiology professors, ‘Scotch-tape’ Marshall Chasin has always championed early analogue treatment (for example limiting) ahead of the processing. That’s pretty standard in sound studios.