[music-dsp] Fw: A little question about DSP performance

robert bristow-johnson rbj at audioimagination.com
Fri Oct 2 16:53:52 EDT 2009

On Oct 2, 2009, at 11:28 AM, Didier Dambrin wrote:

> That harmonic is at 2500hz so it can't really be a matter of age.

oh c'mon, Didier!  <begin sob story> i dunno how old you are but i'm  
pushing 54, my dad wore hearing aids in his later years, i grew up  
listening to loud rock 'n roll in the 70s (like big loud Blue Oyster  
Cult concerts long before the Reaper), i've already been tested and  
i'm down 30 dB at 4 kHz in one ear and down 10 in the other.  <end  
sob story>  i do not count myself as an authority in a tough  
listening test, and in fact, i can't hear a difference at all.  now,  
because it's tough, we wouldn't be intellectually honest enough if we  
didn't settle the fact with some kinda blind testing.

so Didier, i might not have time to fiddle with this, but if i find  
some, may i make some copies of that and switch around the tones.   
there would be 3! permutations where the difference can be seen and  
whether heard is being tested.  of, if there is someone with tons of  
time on hand to do that.  i think this is epitomizes an application  
of blind testing.  we can keep Didier's original as the control and  
call it "ABC".  then people have to listen to one of the six  
permutations and say which one it is. looking at the waveforms before  
listening would be cheating.  we don't need no double-blind (it  
actually would be that if the "administrator", whomever that is, does  
not know which is which), because if people peek, the experiment is  
compromized anyway.

> Are you listening through headphones?

yes.  all's i did is let iTunes play it looped.  you have it at the  
perfect length, relative to the spacing between tones, there's no  
break in the beat.  i listened at various levels.  i soon lost count  
as to which one was first.


r b-j                  rbj at audioimagination.com

"Imagination is more important than knowledge."

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