Audio Test tone for setting speakers up

[Bruton]

Does anyone either have a test tone with a DC waveform or know how to make sony soundforge make a dc waveform??

[Pyrotechnic]

http://www.downloadjunction.com/product/...index.html Anything on there any good? And a DC waveform? How does that work with sound?

[Ant]

Why not just use your ears or is old age getting to you!?

[Pyrotechnic]

Right, Audacity can't do it, it can remove DC offset but not add it, I have another program called 'MySoundStudio' that can generate tone and add offset. Unless you need it now, I can bring you a copy when I come and pick my car up. OR I've nothing to do, so if you tell me what tone frequencies you want I'll knock up a CD. And just to confirm, by DC you mean a sin wave shifted from 1 to -1 to 1 to 0, not a squarewave?

The top or the bottom (or I'm talking out my arse and neither)?

[Newth]

normally you'd start with a 0dB offset sine wave.

[Bruton]

Ant Wrote:Why not just use your ears or is old age getting to you!?

so how do you use your ears to test if a speaker is in 180 degrees out of phase?
Imagine joe blogs who thinks he knows what he is doing brings you a car cos the sound is gash. Now hes installed 10 speakers each side of the car but doesnt know which are in or out of phase now do you remove the speaker wires (providing you know which is which and ive seen some shite installs) dob a battery onto each or get someone to watch while you dob it and note which way the cone moves??

Or do you create a dc waveform to go on cd so that all you do is pop your cd in then go to all speakers and adjust accordingly.

After thinking more it may be better to have a sloping dc wave form that starts at 0 degrees and slopes to 90 degrees then drops straight to 0 again.

So to my modified question how to create a sawtooth waveform with DC offset. I can remove the DC offset but adding it is a different kettle of fish.

I reckon that 20hz should do the job so that i can see the cone gradually move outwards then click to ov.

[Pyrotechnic]

Just knocked this up, 30 seconds at 20Hz saw-wave with +ve DC offset, looks like this:



Sounds a bit fast though, maybe 1Hz would be better? (I'm making it now anyway just to see)

[Bruton]

OK i think ive done it now
Created a sawtooth 20hz at -6.2dB (closest amplitude i could get to 50%)
Adjusted the DC offset by 16000 which gives me a nice sawtooth only

also altered my sub vibration test tone which rocks da house
link here

[Bruton]

looks like we both cracked it at same time Its a visual thing so you can see the cone move slowly to the front then flick back to center

[Pyrotechnic]

Bruton Wrote:looks like we both cracked it at same time Its a visual thing so you can see the cone move slowly to the front then flick back to center

Great minds and all that ;]
I still think 20 is too fast, unless you can see something move at 20 times a second (the human eye maxes out at around 24Hz), even at 1, I've just tested it on my stereo and I couldn't see any real difference between negative, none and positive offset...