We’ll have to ask William Shatner. I know he uses a CPAP, but not sure about hearing aids. However at 88 the odds would seem good…
I found this PowerPoint presentation by Siemens on Understanding Compression which looks like it dates back to 2006. Here is one slide which seems to suggest they give a choice of Syllabic or Dual Compression and they are both adaptive. But, it is not exactly definitive and they never really define what Dual is. The software does give a choice if you override the defaults. Interestingly it is set on a channel basis, so conceivably you could set it differently across the frequency spectrum.
Haha. Shatner was famously one of Jastreboff’s tinnitus patients. I’m sure he must have hearing aids at this point.
I thought one of the adjustments that could reduce the problem of hearing distant conversations more loudly than desired was the kneepoint. But I don’t know how one does that.
As I understand it, the knee point is the point on the gain curve where it changes slope, usually to more compression. If the knee point was moved down, it would go to the next gain slope at a lower input sound level.
I made an appointment today at Costco to try the the DSL v5 formula. My fitter happened to be there and made the appointment. I am obviously her “best” customer as she does not even ask me my name. She even offered to do the fitting on Christmas eve.
Are you sure there isn’t more to this relationship than you think? 
I hear what you say, but all I need is a pair of hearing aids that work as well as they can. They are pretty good right now, so I will have to eat some crow if DSL messes them up…
Obviously my attempt at humor was weak, very weak. 
High compression helps with comfort but also hearing soft sounds. The NL2 formula generally prescribes higher compression settings as they are trying to maximize speech intelligibility.
This approach works well in quiet but breaks down in noise where the extra soft sounds amplification boosts noise arriving from a distance, and for non speech type signals like music where the compression kills important dynamic modulations.
Lower compression settings (or more linear settings) are often attributed to a more natural sound quality and may provide better performance in noise or in situations where soft sounds may be annoying. Music signals are also less constricted dynamically so less compression can help here as well.
A system that can modulate the compression is probably the ideal setup and for this reason a lot of manufacturers have adaptive compression systems.
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I got it and chuckled. But, she is married, as am I, and she is far too young for me. But, on the other hand, I am only 70, and when you are in the hearing aid fitting business, 70 might look pretty young compared to the usual crowd.
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Well we will see what it will do in a week or so. I am a touch worried about it as the sound of my aids is doing the best they have so far. So, there is a bit of a “if it ain’t broke, don’t fix it” thought in my head too. In any case I know how the software works and it is a few clicks to put it back to where it is now. No need for REM, and I could likely get it done by just dropping the aids off for a few hours.
As far as adaptive compression goes, I believe these aids have it. But, it only seems to apply to transients, with the attack and release time constants.
Are you describing the (comfort-clairity) settings?
Thanks
I am a few hours into using DSL v5 for a prescription. My gain may still be slightly high for my left ear which does not take to lots of gain very well. Overall the impression is that sounds are quieter and more natural sounding. There is slightly less bass perhaps. For sure there is more clarity in the high frequencies. I am hearing things I did not hear with the SmartFit/NAL-NL2 prescription (they were pretty much the same). The SmartFit seemed to give a real edge to certain voices on TV, and particular ones where the original sound quality was not the greatest. That seems to be gone. So far, so good.
I was getting a touch of feedback in my left ear, so I went up from a Small to Medium closed click sleeve, and it seems to help. I noticed when the fitter was doing the testing that my left ear was more sensitive to feedback. The no-go feedback zone on the screen was larger than the right ear.
Will be interesting to see how it does in different environments. Have not tried listening to music on my stereo yet.
Interestingly the fitter played with the gains on the left ear for quite a bit of time, and in the end had a curve that looked almost exactly like the one I produced in my first post.
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No I believe you are referring to sound recover2 which is frequency compression, a different feature altogether
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In the Phonak Target Global Tuning section there is an option to adjust the compression (gain compression) to semi-linear or linear. If someone wanted to try less gain compression that would seem to be an easy way to try it without changing the basic formula. However it changes both loud sounds and soft sounds compression. I was interested in changing the soft sounds, but not the loud.
Have now tried listening to my stereo while using this DSL v5 prescription with my music program. There is no noticeable decrease in bass. If anything the highs are clearer. I am hearing some things in the music that I did not hear before. I am going to have to go back in to get an adjustment made on my left ear as it is more prone to feedback than I like.
I get the same impression as you did with the DSL v5 Adult on my OPN as opposed to the Oticon VAC+ rationale. Things sound sharper with no noticeable decrease in the low frequency. I resort to this DSL rationale when I run into challenge speech in noise situation and want a little more boost on the highs. But normally I just use the Oticon VAC+ which sounds more natural to me, probably just because I’ve been used to it for a long while.
Compression ratios in sound studios run from 1.5 to >10 (one box would even over-compress, make big small and small big). Ratios 4:1 to 10:1 are used to restrain over-enthused singers so they “sit in the mix”. It is very probable you do NOT want 4:1. The old literature on WDRC seemed to like 1.5 maybe 2. This is also where I would go to map a wide-range performance “linearly” onto narrow DR media (cassette tape), though cheap tape generally did not sport WDRC.
How much floor-squeak and refrigerator rustle do you want to hear? While ‘normal’ ears can hear 0dB SPL, the background ambient in most homes is 35-45dB SPL; and the very young ignore or discount those very soft sounds. You have not heard them in years. Empirically you set base gain to get these sounds just-audible, and the first knee not much higher. A 2nd knee was a luxury in my old job, but would go at the louder part of the meat of the performance, to shave over-peaks. 62 seems low. I’d have to think on it but it’s late.
They mean different things to different people. However “Dual” used to be a very specific meaning. A semi-syllabic, 0.1 second, time-constant so peaks did not distort (tape, transmitter, phono). And a longer, 1 sec, TC so a sustained loud sound would be ducked and not pop-up at every break. The two together can work Amazingly Well. I am so glad I invented it in the 1970s. (Based on a $$$ product from the 1960s, which turns out got it from a product in 1938…)
YOU want to play with those compression ratios. However I agree completely that this +plus+ the strong EQ and a rather opaque “set of knobs” means you will make a muck-up before you get good at it. I have spent an hour+ setting-up compression on a 10-minute track. With less controls than modern HAs have hidden away in their bowels.And some fairly awkward artifacts.
The outcome of going to DSL v5 is that overall sounds seem more natural, and less harsh, except for the occasional female “s” sound. There might be a slight loss in overall volume as I have noticed that I have tweaked the TV volume up some from where I was with NAL-NL2 (SmartFit). We were out to a restaurant a couple of nights ago that was fairly loud and I did quite well hearing conversation at our table of 4. Didn’t have to resort to my Noise/Party program, or narrow down the microphone focus, or turn the volume down.
The unique feature of the DSL v5 at least with the type of loss I have is that compression is very low and approaching 1.2 for the soft sounds, but there is still some significant compression in the loud sounds, with up to 1.7 for compression. But still way less than what I was getting with NL2.
I can’t detect any impact of any changes in the time constants. I believe they are supposed to be adaptive in any case, so who knows what they really are…
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