On Sat, 1 Apr 2017 19:12:21 +1100, Trevor wrote:
On 1/04/2017 7:08 PM, Don Pearce wrote:
On Sat, 1 Apr 2017 18:58:46 +1100, Trevor wrote:
On 1/04/2017 5:00 PM, Don Pearce wrote:
On Sat, 1 Apr 2017 14:21:28 +1100, Trevor wrote:
On 31/03/2017 6:55 PM, Don Pearce wrote:
On Fri, 31 Mar 2017 07:46:18 GMT, (Don Pearce) wrote:
On Fri, 31 Mar 2017 18:33:50 +1100, Trevor wrote:
On 31/03/2017 6:13 AM, Don Pearce wrote:
On Fri, 31 Mar 2017 08:10:03 +1300, geoff
wrote:
But what do you do when the years move on and some correction is
needed? Here's a pair of self-administered audiograms, from 2001 and
three days ago. I've actually won a bit of bass, but the top end is
vanishing fast.
http://www.soundthoughts.co.uk/look/audiogram.png
These were taken with a nice pair of Stax phones, so they should be
pretty reliable. On the recent one you can see a masking peak at 4kHz
caused by tinnitus.
I take it that it is upside-down to the usual sense ?
No, that's a normal threshold curve. That is how loud sounds have to
be for me to just barely detect them.
Not a threshold curve as plotted by an audiologist however. Geoff is
right, it's upside down to what is normally accepted.
Well, just so we are clear - the x-axis is frequency and the y-axis is
SPL. I've plotted it the way it makes most sense to me.
Does this make more sense?
http://www.soundthoughts.co.uk/look/audiogram2.png
Yep, except the SPL axis should be +10 to -80dB.
No, the SPL axis is correct.
For YOU perhaps, but NOT as shown on an audiologists graph as I have
been saying. The figure is normally shown as the amount of loss relative
to "normal" hearing threshold. I suggest you check out graphs on any
hearing aid manufacturers site, or any audiologists site for reference.
YOU can use whatever YOU want of course if you don't want to worry about
convention.
Sure, but I wasn't interested in the relative measurement - why would
I be when I had measured the much more useful absolute data?
HOW did you calibrate your system to provide "absolute SPL' then?
Bet it doesn't! Relative is a lot easier.
I used an SPL meter and a fixture. Stax headphones make this a
reliable method because the sound generating area is so large. You can
move the measuring mic around by tens of millimetres and the level
doesn't change.
d
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