Skip to content
HearingTracker
Log in

16 vs 24 bit converters and HA Audio quality,

This topic is closed.

26 replies6.6k viewsLast reply

Jump
Link to this topic

In reply to @Volusiano

@Corona1 said:

Isn’t the sample rate like 44.1 more important than 24 bit?

I have been wondering about direct streaming and audio bitrate/compression? I’m guessing it’s low bitrate vs Bluetooth headphones? Is direct stream to Android better than iPhone? I have a cool idea for Bluetooth 5.2 streaming to HAs and headphones at the same time so you get bass but perhaps still compressed audio.

HAs say they have over 100db headroom?

Edited

I use Oticon OPN S 1 aids. The Oticon OPN are MFI aids so they use the Apple defined protocols for communicating with the aids. I haven’t found a good description of the MFI hearing aid protocols/bit-rates, etc. So I have no idea how they compare to classic or LE Bluetooth or Android. However, all Bluetooth audio uses some codec to transmit audio as Bluetooth doesn’t have the bandwidth to transmit raw CD quality stereo audio.

One way of discerning some streaming performance is to look the specs for a TV adapter. The technical data sheet for the Oticon TV Adapter 3 for my aids specifies an audio bandwidth of 10 KHz/stereo from input to hearing aids. It also specifies a Latency (TV adapter input to hearing aid speaker) of 25 msec for analog input, 28 msec for digital (TOSLINK) and 45 msec for Dolby Digital (TOSLINK).

For the hearing aids themselves, the input section is able to handle up to 113 db without distortion and artifacts according to the OPN S product guide. There is also a statement that the processing works down to 5 db SPL implying a range of over 100 db. The same document states that the A/D uses 24-bit sampling for each microphone and the auxiliary input. It also uses a 24-bit . The fitting bandwidth is specified as 10 kHz for the S 1 and 8 kHz for the S 2 and S3 versions.

Many of us hearing aid users have large losses at high frequencies and voice is not considered to have that much content above 8 kHz so cutting off response at 8-10 kHz is probably common but I haven’t tried to find the high cutoff frequency of other hearing aid brands/models. Your idea of both hearing aids and headphones may/may not work if the latencies of the two devices aren’t similar and if the hearing aid system blocks higher frequencies. The headphones would probably have (much) better bass response below 100 Hz or so.

In reply to @iblaineman

See the Wirecutter review link in the following post. The following quote is from the very end of Butterworth’s article (LE Audio and the Future of Hearing - #47 by jim_lewis):

Once again, the differences in sound quality among these codecs are subtle at best. This is why we don’t make the inclusion of certain codecs a major factor in evaluating Bluetooth headphones and speakers. The acoustical tuning of the speaker or headphone drivers and enclosure, and the tuning of the device’s digital signal processor, have an exponentially greater effect on sound quality—and your day-to-day enjoyment of your audio gear—than the Bluetooth codec does.

I would imagine the same considerations apply to ’s - just further add the fit and gain adjustments in your HA’s to the list of things to consider first. He does mention in the article that the best situation is if the sound source, the broadcasting device, and the receiving device (e.g., headphones) all employ the same audio codec, then you will get the sound reproduced in your ears ungarbled by any cross-translation between codecs and he does say that the Sony audio codec is somewhat appreciably better than any of the others. I am mixing apples and oranges here a bit between audio compression and BT transmission codecs but I think the general idea is that you can’t make a silk purse out of a sow’s ear.

In reply to @biggar

@biggar said:

bably common but I haven’t tried to find the high cutoff frequency of other hearing aid brands/models. Your idea of both hearing aids and headphones may/may not work if the latencies of the two devices aren’t similar and if the hearing aid system blocks higher frequencies. The headphones would probably have (much) better bass response below 100 Hz or so.

I thought with Bluetooth 5.2 and the ability to stream to multiple devices in sync would be a cool way to have and headphones at the same time. I also read in the spec that 5.2 can either have the same audio quality using less power and/or can have better audio quality at the same power consumption as current Bluetooth. Interesting I streamed test tones to Widex Moment and seem to get frequencies from around 130hz to 7khz. I can only hear to around 9 something khz but think hearing the extra frequency range would be helpful. I’m using an iphone 7 with Bluetooth 4.2 and had some audio glitches while doing this.

I agree with another post that HA manufactures don’t list what protocols they use. I would guess that Moments user Bluetooth 5 judging by the widex TV play which says 100Hz - 7kHz with 24ms latency. So I wonder if they Widex uses AAC protocal to stream to iPhone. I wonder if Phonak user proprietary protocols. I wonder if HAs could have wider frequency range or would that require to much power/processor and shorten battery life.

Related discussions