Calculate maxSPL

[Charles Darwin]

Is there a simple(ish) way to calculate a theoretical maxSPL when one knows the linear excursion limits and the lowest frequency a driver will be fed without resorting to computer simulations?

[Ron E]

Originally Posted by Charles Darwin

Is there a simple(ish) way to calculate a theoretical maxSPL when one knows the linear excursion limits and the lowest frequency a driver will be fed without resorting to computer simulations?

Let me google that for you

[Charles Darwin]

Not as helpful as you appear to be thinking.

Basically the question is this: Driver X has a linear excursion of Y mm. If I feed it a band-limited signal say 100Hz to 2kHz how loud could it theoretically go without exceeding its linear excursion?

[dewardh]

Not particularly simple(ish), but perhaps a little more helpful

Electrical and mechanical limits

[bjorno]

Originally Posted by Charles Darwin

Not as helpful as you appear to be thinking.

Basically the question is this: Driver X has a linear excursion of Y mm. If I feed it a band-limited signal say 100Hz to 2kHz how loud could it theoretically go without exceeding its linear excursion?

This calculator might help you:

Piston Excursion calculator

b

[Charles Darwin]

Thanks bjorno, that indeed does the trick.

It could be that dewardhs link does the same but for some reason the linkwitz lab site never properly loads. It starts, gets stuck and eventually shows an error message.
Thanks anyway!

[Don Hills]

If you're trying to work out how much bass you'll get in a given room, it's quite simple. You need driver sd (surface area), xmax (driven excursion), and room volume. The frequency is irrelevant provided that it is below the lowest room resonance mode. At frequencies below the lowest resonance, the in-room SPL is determined by the room volume difference between "cone in" and cone out".

The formula is:
SPL = 197 + 20log(delta vol) - 20log(vol)

1. Calculate the amount of air displaced by the driver at maximum excursion (diaphragm area times xmax). For example, a typical 15 inch driver: 890 mm2 area, 12 mm xmax
89cm2 * 1.2 cm = 1006.8 cc = 1.07 litres.

2. Calculate the room volume. For example, 4m * 3m * 2.4m = 28.8 cubic metres (28800 litres)

3. Do the math:
197 + 20log(1.07) - 20log(28800) = 108.4 dB

See this post, and the threads it links to, for background info.

modeling room gain

Also see Seigfried Linkwitz's notes:

http://www.linkwitzlab.com/images/gr...losure-spl.gif

The usual disclaimers apply - for example, the SPL is theoretical and depends on a "perfect" room, and ignores resonances and "beaming" effects at higher frequencies.

[Charles Darwin]

Cheers mate!