Multi tone speaker response

[dweeeeb2]

Is there a measure of a speakers ability to play multiple tones at once? My understanding is that FR data is generated by sweeping through frequencies, only asking the speaker to produce one frequency at any given time. Is this correct?
To me, the ability of a driver to produce multiple frequencies at once is incredible and it is taking a bit for me to understand. Is this measured? I can envisage say 2 tone sweeps occurring at the same time at say "X" octaves apart.

 

[fpitas]

You mean, like the 32-tone test that Amir runs?

He runs that on amps, but now that I think of it, not sure what he does for speakers.

 

[fpitas]

I can't see that Amir does IMD testing. I bet the results would be disappointing for a lot of smaller speakers at reasonable output levels.

 

[voodooless]

You’d like to do the multitone ideally with a level distribution comparable to music, so something like this:

This will give a much more realistic picture of how IMD affects real music. Most notably bass is about 15 dB hotter than 1 kHz. Large excursion will influence IMD quite a bit. With a flat frequency response you will not see this effect as much.

 

[Sokel]

Like this one? :

(measured by @Nuyes)

 

[fpitas]

Like this one? :

(measured by @Nuyes)

I think voodooless has a good point about the frequency roll-off, though.

 

[Sokel]

I think voodooless has a good point about the frequency roll-off, though.

Of course he has!
The above is Klippel's fixed test I think so there must be a lot of documentation about it.

 

[dweeeeb2]

Like this one? :

(measured by @Nuyes)

Cheers! Ive been going around in circles because to me a single sweep, in the manner it is done for FR graphs just doesn’t feel sufficient to assess a speaker. I accept that its standard practice, so I just wanted to see why multi tone testing is considered as not required on here.
Ill see if I can find the Klippel info.