Absolute Auditory Threshold Test on Audacity

[greenlily]

Hello everyone,

For a college research project, my partner and I are attempting to use Audacity to create an absolute auditory threshold test. This is basically a hearing test, which involves running a series of tones in increments and decrements and noting the lowest points participants can hear the tone at. My partner and I will need to quantify the tone levels though, and we want to use decibels to do so. I know we can use the amplify feature to take the default tone and amplify and de-amplify it by a certain amount of decibels. What we are wondering is, how accurate is this process? If we amplify the default tone by 10 db, is it truly 10 db louder? We also can't seem to figure out how many decibels the default sine tone is, at 440 Hz and amplitude at .8. Access to equipment like sound pressure meters is limited, so if anyone knows how many db the default tone with these specificities is, we would appreciate it if you could let us know.

If anyone has any experience with creating absolute auditory threshold tests using Audacity, suggestions would be greatly appreciated!

Thanks for your help, let me know if I need to provide more information.

[kozikowski]

is it truly 10 db louder?

No, it's 10dB higher signal level. You don't hear in a straight line like that.

You can convert the timeline to dB readings with the drop-down tools on the left. and you can make the bouncing ball sound meter much more accurate by grabbing the right edge and pulling sideways.

http://kozco.com/tech/audacity/Audacity1_playback.jpg

You can also undock them for even better accuracy.

http://kozco.com/tech/audacity/Audacity1_full.jpg

You should be in Audacity 1.3.12, not 1.2. Audacity 1.2 is very old and can have problems with newer Macs.

http://audacityteam.org/download/

You can install both versions safely, but only use one at a time. Audacity 1.3 projects will not open in 1.2

if anyone knows how many db the default tone with these specificities is, we would appreciate it if you could let us know.

dBSPL (sound pressure level) is completely at the mercy of your amplifier volume control and has no relationship to the dB readings in Audacity, other than once you establish a relationship, it will be constant unless something breaks.

Koz

[kozikowski]

Have you ever sat through a hearing test? The last one I had told me to keep stepping on the tone. They put me in headphones and played tones to me and I would press a button until the tone went away -- faded out. Repeat for many different pitch tones. Then they correlated the button presses with the frequency and amplitude of the tones and that's the inverse of my hearing.

If a tone gets to maximum volume and I never hear it, then I'm stone deaf at that pitch.

Koz