Pink_isn't_well wrote:
I have some speaker systems and I want to test their
frequency
response. I'm not a sound engineer or anything and I don't
really
know much about audio. But I assumed I could do this in
the
following way.
I found a test clip on the net which has several
frequencies in the
audible range 20 Hz - 20 kHz, each playing for 2 seconds.
I open it
in Nero Wave Editor and it shows that it has the same
level from
start to finish.
Then I take my mic and place it close to a speaker, I mute
the
other speaker and playback this file, recording with the
microphone. I then save the recording uncompressed and
open it in
Nero Wave Editor to see how loud/quiet each frequency is.
My understanding is that the recording should be as close
as
possible to the test file that I use as input.
I did this with two different speaker sets and you can see
the
results below:
http://img224.echo.cx/my.php?image=t...esponse7xo.png
http://img224.echo.cx/my.php?image=o...esponse8hv.png
It may not be as bad as it seems. One problem is that the
amplitude scale is given in percentage, when frequency
response is usually plotted on a dB scale. For example, 50%
on your FR curve is only 6 dB down from the peak level, and
10% is only 20 dB down. +/- 10 dB frequency response is not
all that bad, but it shows up as 10% - 100% on your chart.
Original test file (downloaded recording):
http://img156.echo.cx/my.php?image=testclip7ci.png
Is this lousy frequency response or what?
Hard to say.
Am I doing something wrong with my testing method?
For sure. As Don Pearce says, measuring the FR of speakers
correctly is a tall order, and your methodology is very
simplistic. If you want to see a better job of FR testing,
try downloading this softwa
http://audio.rightmark.org/downloads/rmaa55.exe
You also need a better microphone. About the cheapest one I
can recommend is this one:
http://www.zzounds.com/item--BEHECM8000
To interface it to your PC, you need this mic preamp or
something like it:
http://www.music123.com/Rolls-MP13-M...p-i11840.music
If you want better measurement softwa
http://www.etfacoustic.com/