I'm creating a test tone CD - Anyone else interested?

[EasyTiger]

As part of my ongoing system optimisation efforts (integrating a RELQ150MkII with Kef Q5's and also setting up the pio 2011 EQ) I have decided I need some test tones (to use with a SPL meter).

I have some software that I can use to generate the test tones I need (onto CD) and was thinking of:

1. A disk with Left only tones 11Hz to 109Hz (tracks 1 to 99), for 20 seconds each tone.
2. A disk with Right only tones 11Hz to 109Hz (tracks 1 to 99), for 20 seconds each tone.
3. A disk with Left and Right tones 11Hz to 109Hz (tracks 1 to 99), for 20 seconds each tone.

Would anyone else be interested in these?

Has anyone got any ideas about what else would be of use (sweeps, higher frequencies)?

 

[eviljohn2]

CD text that showed what frequency was being played might be helpful.

 

[engaged]

I found an application for my laptop (Apple iBook) that'll generate tones, sweeps, and noise; white , pink, blue and brown. Was thinking about just hooking it up to my AV receiver and using it that way - need to get a sound level meter first but every bugger seems to be out of them.

 

[~Kev H~]

Can you remember where you found that application? Was it just for Mac ?

My 20-39PC+ should arrive tomorrow and I've got the cable to connect my laptop to my amp.

Even without a sound level meter it would be nice to try and get a flat response by ear.

Cheers - Kev

 

[engaged]

Originally posted by ~Kev H~
Can you remember where you found that application? Was it just for Mac ?

I found one for the PC too, but it's upstairs and not very mobile - link!

 

[~Kev H~]

Thanks very much engaged. Thats exactly what i'd been hoping to find when searching through pages and pages of irrelevant google results the other day!

Kev

 

[Nimby]

I wonder how flat the frequency response is when using one of these software tone generators?

Or whether it depends on the quality of the computer sound card.

Any computer sound experts on board who could advise please?

Nimby

 

[~Kev H~]

I have never used anything like this to test frequency response of speakers, Just doing this by ear is giving me some strange and unexpected results.

Doing a 60 second sweep down from 80Hz to 20Hz my B&W 604's decrease in volume as I would have expected, at first, and then seem to increase in volume below 50Hz until a peak at say 40Hz and THEN the volume tails off.....

Is this the phenomenon that is "room accoustics" or would this be due to the bass reflex design ???

Might pull the covers off and plug the ports.. see if that "smooths" things out.. any suggestions??

 

[Nimby]

Almost certainly a room effect. What are your room dimensions?

These should help:

http://www.mhsoft.nl/Helmholtzabsorber.asp

Just enter you room dimesions in the boxes provided.
(I recommend adding this one to your favorites)


And for those lucky devils with Excel onboard:

http://www.pvconsultants.com/audio/reflection/rrc.htm


Nimby

 

[~Kev H~]

Thanks for the links Nimby, putting the length of my room into that page indicates a fundamental frequency of 41Hz, exactly what it sounded like! Putting the port blockers in has reduced it a tiny amount but there is still a definate peak there.

I will look more at how to deal with this problem once I've had a play with my new delivery.. the man from BAX global has just been have pity on my neighbours!

Regards - Kev

 

[pwiles1968]

I get the same thing at 35Hz with my 603's, it bugs me a little know I know it is there but it does not appear to be overly audible in music etc, Kick drums do sound damn good though.