Display SPL vs time?

[kozikowski]

<<<2kHz to 20kHz>>>

We do need to be careful about that. Some tweeter systems are designed for intermittent usage typical of a loud orchestra and will turn into a pile of cinders with a sustained test signal. It's one of the reasons I haven't posted a number of test sounds in a "visible" part of my web site. by necessity, they need to be run at low level. If you crank it up because you have trouble hearing it, that may be the last thing you send to that speaker.

Koz

[alatham]

I think most SPL meters will allow you to make an unweighted measurement, but thanks for mentioning that, Steve. A-weighting and C-weighting will both throw off the measurements, I think. This stuff is a bit out of my area of expertise though, I haven't the money to do any acoustic treatments yet, I'm waiting until I move into a house first (hopefully in the next 2 years or so).

[steve]

<<<2kHz to 20kHz>>>

We do need to be careful about that. Some tweeter systems are designed for intermittent usage typical of a loud orchestra and will turn into a pile of cinders with a sustained test signal. It's one of the reasons I haven't posted a number of test sounds in a "visible" part of my web site. by necessity, they need to be run at low level. If you crank it up because you have trouble hearing it, that may be the last thing you send to that speaker.

Koz

Oops, I guess I should have mentioned that.

It's always good to point out cautions with this kind of thing - the system should not be driven beyond it's design limits in any frequency range. It is also true that speakers are not designed to handle the same levels at high frequencies as low frequencies, so the speakers should not be driven hard when testing above the speakers cross-over frequency (typically somewhere between 1.5 - 5 kHz)

However, good speaker systems should however be able to handle more than intermittent usage. If not, there would be problems for a lot of people listening to the "Gladiator" sound-track as it has sustained sections that contain a continuous narrow band noise above 16 kHz at quite a high level. (I believe this is an artifact created by a synthesizer that they were using).

Certainly you should not "crank it up" in the high frequencies because you can't hear it as you certainly do run a risk of frying your tweeters.

A better test would be to have a tone that progressively decreases in amplitude by about 3 - 6 dB per octave above 1 kHz, but that makes the whole measurement thing more complicated.

So yes, keep the levels sensible, particularly in the high frequency range.