Okay, time for a recap of what we have tried, what works, and so on. After several days of listening to each incremental improvement, I am now ready to state some definite conclusions.

  1. Regarding asymmetric hearing – once again, despite the ability to split L/R channels and apply separate EQ to counteract peculiar instances of hyper-recruitment and decruitment that differ between each ear, I can now state that I really do prefer equal treatment to both L/R channels. This agrees, overall, with the conclusions reached after surveying so many other listeners with Crescendo. People prefer equal ear treatment, even when they have obvious asymmetry in their hearing.
  2. Regarding pre-treatment to help overcome faint scintillation artifacts in the background under conditions of severe hearing correction levels, I can now state that cascaded Crescendi work better than everything else ever has before.

As I have stated before, just about anything you do sounds like an improvement, when you have hearing impairment. The trick is to discern eventually when it really does sound better, as opposed to when it just sounds different.

When things sound different they are new sounding and immediately attractive. But they aren’t necessarily better. It is only with sustained critical listening that you can eventually discern better. But this is always a subjective judgement, not amenable to mathematical analysis.

With equal ear pre-treatment for my extraordinary and asymmetric recruitment hearing conditions, both ears get pre-treated the same way. The pre-treatment with EQ is less than appears to be needed when treating each ear separately. The separate treatment was obtained by listening to a rising sine sweep and visualizing where the sound arises. Then the EQ for each ear was separately adjusted until I more or less managed to keep the rising sweep centered.

But under conditions of musical listening, this manner of independent EQ sounded harsh and somewhat unpleasant, compared to a much lower degree of EQ at the significant frequencies fed equally to both ears.

I have to conclude that, despite the asymmetry in hearing, my brain has learned to accommodate, and the equal treatment just sounds more like what I’m accustomed to hearing.

This kind of effect is not unknown to users of hearing aids. At first they sound overly bright and harsh. And it is true that after some time, your brain accommodates the new brighter, harsher, sound. You get accustomed to it gradually. But that doesn’t make it correct.

For hearing aids, we use them primarily to help us discern human speech. And it is also true that creative sound distortion can actually help improve speech cognition. But you really don’t want that same kind of creative sound distortion to be applied to your music. It sounds just awful.

Secondly, regarding the cascaded Crescendo units, it works well because no single stage has to exert more than 20 dB of makeup gain. Both are hyper-multi-channel nonlinear compressors, whereas CLAS is only a 2-band NYC Compressor. So nothing could be better for the second Crescendo than to have another hyper-multi-channel compressor ahead, making the sound field in each Bark band easily corrected.

I have been listening over and over to Rimsky-Korsakov’s Scheherezade – an unusually difficult piece to listen to with hearing impairment. The measured loudness range across the entire piece is more than 21 dB. This dynamic range is about 3-7 times greater than most Rock music. So it is really challenging.

Secondly, much of the extreme faint end of that dynamic range is in a solo violin at the highest octave registers. So not only is it very faint, but also very high frequency. This is the most difficult situation to overcome.

Thirdly, much of the incidental and background music is comprised of high string sections, so there are lots of opportunities for the development of scintillating sounds at the faint levels.

Using stacked Crescendos, with the first tuned 10 dB below my actual hearing threshold elevation, and the second tuned to my actual elevation, works fabulously well across all of these challenges. Not a touch of the scintillation in the soft sounds. I hear all of the faint, high, solo violin. And the full 22 dB of dynamic range is accommodated, making for some very exciting listening.

  • DM

Author: dbmcclain

Astrophysicist, spook, musician, Lisp aficionado, deaf guy

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