Power handeling question

[woody]

I just picked up some drivers that are rated for 20w if crossed
over at 200hz at 12/db oct. If I use a 6/db oct xover how can
I calculate how much power the speaker will take at 300hz or
500hz. I am talking about from a x-max standpoint and not worried about the thermal calculations.

Thanks,

bob12345678

 

[Jimmy154]

There isn't anyway to figure it out.

And if anyone tells you any different they lying or don't know what they're talking about.

Sounds like I'm but I think this is right.

 

[Dave Bullet]

At half the frequency (an octave down) - the driver has to move 4 times the volume of air to reproduce the same SPL (I hope I quoted that correctly).

Does that help? Also - if this is a bass driver - if you are happy with its excursion for the power you plan to feed it at 200Hz - then the same power fed into it above 200Hz will result in progressively less excursion - so you wont have a problem with the mechanical limit.

Have I missed the point?

David.

 

[Dave Bullet]

Sorry bob - re-read your post.

I calculate how much power the speaker will take at 300hz or 500hz

Um - according to Dave Bullet theory 🙂 - it will take 4 times the power at 500Hz than it will at 250Hz before reaching the same excursion.

Or have a just invented a law of stupidity (a little knowledge is a dangerous thing) 🙂

David.

 

[Redeye]

Absolutely right. Power ratings on speakers are a little bit of a guess at the best of times because there's so many variables involved. Sure, you can measure by various methods, but real source material (as opposed to noise used for measurement)among other things is a massive variable.

At the frequency range you're talking about, between 200Hz and 500Hz, I'd say that the energy content of music signals is of more concern than the potential cone excursion. Most of the excursion will probably be due to frequencies a little lower than this, but there's a lot of energy content which will warm that voice coil up. There will also be a little more energy through the driver because you're only using a 6dB xover rather than the rated 12dB crossover.

Hope that helps a little.

 

[planet10]

I just picked up some drivers

Woody,

What are they?

dave

 

[woody]

Thanks for all the responces.

Dave, I picked up a pair of baby BG ribbons like the RD 28.1
but only with 40% there legnth. The RD 28.1 is rated for a
minimum xover of 150hz at 24db/oct 65w program so I figure
my drivers would have a rating of about 25w program if used
with a 24db/oct xover at 150hz. But I was thinking about using them at 400 hz at 6db/oct and can't think of a safe input rating.

Thanks,


bob12345678 AKA Woody