Not an answer to your question but on the topic and very interesting all the same.<br><a href="http://www.ted.com/talks/evelyn_glennie_shows_how_to_listen.html">http://www.ted.com/talks/evelyn_glennie_shows_how_to_listen.html</a><br>
<br><div class="gmail_quote">On Wed, Jan 20, 2010 at 7:57 AM, Giso Grimm <span dir="ltr"><<a href="mailto:gg3137@vegri.net">gg3137@vegri.net</a>></span> wrote:<br><blockquote class="gmail_quote" style="border-left: 1px solid rgb(204, 204, 204); margin: 0pt 0pt 0pt 0.8ex; padding-left: 1ex;">
<div class="im">Simon Fielding wrote:<br>
> My sister is a specialist teacher for hearing-impaired primary school<br>
> children. As part of her curriculum she includes music and in<br>
> particular, nursery rhymes etc for the younger children. She would like<br>
> them to be able to sing these at home with and/or for their parents. For<br>
> those children with non-hearing-impaired parents, this is not a problem<br>
> but many of the children also have hearing-impaired parents. Therefore<br>
> she would like to produce a CD of her singing for the children to take<br>
> home and use. I would really appreciate any help members can give me as<br>
> I am not a professional musician or recording engineer.<br>
><br>
> 1) She will be singing unaccompanied (she is a trained singer and is<br>
> perfectly competent to do this) in an alto register to avoid any<br>
> distraction for the children from accompaniments etc. Does anyone have<br>
> any suggestions about this? (eg effects for recording, effects for the<br>
> headphone mix etc)<br>
<br>
</div>For most hearing impaired listeners, less reverberation is usually<br>
better (if understanding the words is desirable). The effect of<br>
compression very much depends on the accompaniment and/or distracting<br>
noises; in a clean situation compression usually makes things worse (see<br>
e.g., R. Plomp: The negative effect of amplitude compression in<br>
multichannel hearing aids in the light of the modulation-transfer<br>
function. J. Acoust. Soc. Am., vol 83(6), 1988). Try to avoid pops<br>
during recording.<br>
<div class="im"><br>
><br>
> 2) This one's a bit more specialist so you may not be able to help -<br>
> hearing impairment often starts with loss of high frequency response.<br>
> The obvious thing would seem to be to boost these but I don't know if<br>
> that would be correct. Does anyone know?<br>
<br>
</div>If they will listen via loudspeaker and wear their hearing aids<br>
(assuming that they have one), all individualized frequency shaping is<br>
already done by the hearing aid. Listening via headphone is not really<br>
working with hearing aids, thus an individual frequency shaping might be<br>
beneficial. However, for that you need to know a bit about the<br>
individual hearing (e.g., hearing threshold and whether it is<br>
sensorineural or conductive loss, as a bare minimum). A very simple rule<br>
of thumb is to apply a frequency dependent gain which is 40% of hearing<br>
threshold for sensorineural loss and 100% of threshold for conductive loss.<br>
<br>
Linux audio tools can be used to do batched pre-filtering of audio<br>
material based on individual hearing loss (e.g., the command line tool<br>
'applyplugin' which applies LADSPA-Plugins to files, can load equalizers<br>
and set their gains).<br>
<br>
Best regards,<br>
<font color="#888888"><br>
Giso<br>
</font><div><div></div><div class="h5"><br>
<br>
><br>
> Any comments on any other aspects of this project would also be more<br>
> than welcome.<br>
><br>
> Hopeful regards,<br>
> Simon<br>
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</div></div></blockquote></div><br>