Hearing loss and sampling frequency

[sburrell]

Hi,

Having just performed a basic, unscientific hearing test, I've just ascertained my hearing range no longer extends much beyond 16kHz.

Does this mean I would be justified in reducing all my ALAC files to 32kHz (as opposed to 44.1) in order to reduce file sizes?

[Ali Tait]

No. These tests are not accurate. You need to have your ears professionally tested to have a proper idea of how your hearing's doing.

[Reid Malenfant]

No. These tests are not accurate. You need to have your ears professionally tested to have a proper idea of how your hearing's doing.
Agreed :)

Besides which have you noticed the amount of supertweeters for sale out there that extend the response to well over 50KHz?

There is a reason for this, while you may well not be able to hear above say 16KHz as you mention, sounds above that frequency being reproduced accurately will certainly effect what you can hear below your upper frequency threshold :cool:

[Ali Tait]

Yes definately. It's very obvious if you try taking a supertweeter in and out of circuit whilst listening to a speaker.

[Vincent Kars]

Hi,
I've just ascertained my hearing range no longer extends much beyond 16kHz.


You are 43.

Lost the link but there has been some experiments where people listen to music and to the same music but this time with a sharp roll off just above the upper threshold of their hearing range.
They could easily spot the difference.
Maybe this is the intermodulation distortion between the content above and below this threshold mapping into the audible range.
If you have a parametric equaliser you might try to apply a brickwall filter just above 16 kHz.

[StanleyB]

Does this mean I would be justified in reducing all my ALAC files to 32kHz (as opposed to 44.1) in order to reduce file sizes?
You would be considered to have lost not just your hearing;).
A drop in sampling frequency to 32kHz would also knock out the attack of many audio signals. So they would sound softer.

[Barry]

Hi,

Having just performed a basic, unscientific hearing test, I've just ascertained my hearing range no longer extends much beyond 16kHz.

Does this mean I would be justified in reducing all my ALAC files to 32kHz (as opposed to 44.1) in order to reduce file sizes?

Hi Simon,

To answer your question - NO, for reasons I discussed here (http://theartofsound.net/forum/showthread.php?t=11634).

Trust this is of help

Regards

[dave2010]

Not sure about some of the arguments presented here, but I'd suggest keeping the sampling frequency as you have it now, so that you can share your music with others. Maybe you never do this, in which case if space really is a problem for you then reducing the sampling frequency will save some space, but storage is becoming so cheap now that I doubt that it's worth the bother. If space really is a problem, then experiment with changing the sampling rate, and also different lossy compression formats, but then there will definitely be changes in quality. It's then just a question of which cocktail combinations you prefer.

I know my hearing about 15kHz largely went years ago, as eventually I could no longer hear the whistle from TVs and monitors, and fluorescent tubes on buses, though having said that, I think I can still tell when I walk into a lab with lots of such kit - perhaps due to modulation effects between the different sound sources.

Some of the arguments for keeping very high frequencies which in theory most of us can't hear may be like homeopathy, but there could be real effects, perhaps due to aliasing, which can definitely cause super aural frequencies, if present, to be mapped into the audible frequency ranges for most of us. The quality of the equipment and filters used may also have a significant effect. Best to leave material as it is if you want to keep quality I think - and that also means not tinkering with sampling rate or bit depth changes.

[WAD62]

Sampling frequency is not the same as audio reproduction frequency...

44.1, or 96Khz sampling frequencies relate to the number of samples per second, not to the frequency of the sound produced...:eyebrows:

[Vincent Kars]

According to Shannon-Nyquist if one wants to capture the signal without loss one should sample at double the rate of the highest frequency in the signal.
So sample rate/2 (Nyquist frequency) is the highest possible frequency.
44/2=22 and 32/2=16 so if ones hearing is limited to 16 kHz (and will become worse with age) resampling to 32 and losing everything above 16 kHz indeeds result in a smaller file at the expense of losing some information.

[sq225917]

To the OP.

Are you running out of hard disc space?

[sburrell]

WAD62, Vincent Kars has posted what I was already aware of - there is a correlation. If I really wanted to save space and thought what you implied I did, I'd have asked if I could reduce to 16kHz, not 32! ;)

It's not so much space on my Mac that's getting slim, but on my 160GB iPod Classic. Currently it holds exact ALAC copies of my main iTunes library, and I'd like to keep it that way.

Well, seeing as everyone is pretty clear that my idea was ill-informed, I'll forget the whole thing. :o

How does one go about getting a hearing test - just ask my GP for a referral?

[Ali Tait]

I guess so, but a normal hearing test won't cover the frequency extremes in any case AFAIK. Unless you feel you have a hearing problem I wouldn't worry about it.

[DaveK]

How does one go about getting a hearing test - just ask my GP for a referral?

Yes ;) , that's exactly what I did and it happened very quickly. If you are found to have enough hearing loss to justify a hearing aid, please don't be afraid to ask for two (I'm talking NHS 'free' hearing aids here, if you go private the last remark might not be so appropriate as they aren't cheap :) ).
When I quietly asked if it would be possible to have two (industry related hearing loss in both ears), citing listening toi hi-fi as one of the reasons, the Audiologist said that they preferred and recommended fitting two because they work better in pairs, that is the net result of wearing two is better than the sum of the parts, if you follow me. Some people are reluctant to wear two because it doesn't do a lot for their 'street cred', but street cred isn't monitored in the privacy of your listening room :lol: .
And yes, they do make a big difference to the music you hear, well worth it for that alone, but I also noticed that the birds sang louder in my garden when I wore them :lol:
Cheers,
Dave.

[Reid Malenfant]

:lolsign: Street credibility in the listening room, love it :lol: My eyes might be getting a bit lazy (i'll soon need reading glasses i bet), but thankfully my ears are ok :cool: I can't read transistor codes on small signal ones any more, kind of freaky as I used to be able to easily :(

I kind of understand where you are coming from though Dave :) It's still kind of loud hear though & i'm a 45 year old git, we all age differently at the end of the day though :scratch:

Only human :doh:

[DaveK]

:lolsign:...... i'm a 45 year old git, we all age differently at the end of the day though :scratch:

Only human :doh:

Hi Mark,
And I was 26 when you were born :eek: tempus fugit, dunnit just ;) .
Dave.

[dave2010]

It's not so much space on my Mac that's getting slim, but on my 160GB iPod Classic. Currently it holds exact ALAC copies of my main iTunes library, and I'd like to keep it that way.Perhaps a bit tricky this, as we have an evolving situation. My guess is that originally the 160 Gbyte Classic was seen mostly as a portable device, and with 160 Gbytes it can store quite a lot of music, even in lossless formats - perhaps 3-500 CDs. When these gadgets were first developed people were more or less happy to use MP3 or similar codecs, sometimes at shockingly low bit rates. aac, which can be used on the iPods, is not a bad lossy codec, and for many people it's not unreasonable to use lossy compression in order to get more on. I reckon you should be able to get between 500-1000 CDs on with varying degrees of compression, and corresponding quality, or lack of it.

Now I've read of people using the iPod as a transport, perhaps using the Onkyo or Wadia docks, and while some claim that the iPod is no good as a high quality device (probably not - with the obvious outputs), others say it's good with a suitable digital dock. This suggests that it could even be used to store a large collection, but then of course the storage limitations become significant, if its purpose changes from a portable, convenience device, to something which can be used in a larger system.

One option is to shuffle files between your iMac and the iPod - "as needed", though this would lose some (possibly a lot of) convenience. So, if you wanted to listen to 1970s music one weekend you could transfer all those files over, and if next weekend you wanted opera, you could boot out the '70s stuff, and put the operas on. You may not like opera, but I'm sure you catch my drift. Presumably you'd really like to have access to all your files all the time, so this would only partially solve your problem. Another is to recode all your files to a lossy format at a suitable bit rate and then put those files on to your iPod. You'd obviously have to be careful not to lose the original ripped CD files.

Maybe, in the fullness of time, Apple or another provider, will issue something like an iPod with more storage. I wouldn't bet on Apple though, as they seem to be moving more towards networks and cloud storage, with perhaps the emphasis on convenience, and revenue for them and the network providers, rather than quality.