JBL 2460 , 500hz @ 12db ...does it work?

[Dr.db]

Hey folks,

I got a pair of 2460 1" phenolic drivers.... I would like to run them with an active crossover (500hz/12db).
They will be mounted on very short horns, horn lenghts ~20cm and mouth-area aprox 20*20cm...

Is this crossover-point to low ?

Can I run them with full gain ?


Thanks a lot,
Olaf

[HCSGuy]

No. I think the 2460 has a 1200hz minimum crossover (from memory), and no horn that small will load a driver that low. Find out how low your horn is spec'd to go, then use the higher of the two cutoff's for full power.

[Robh3606]

Well I would be careful running a 1" driver down that low. If you look at the spec sheet for the 2461 it looks like it may be OK but it's really pushing things especially on small horns that may not really load them well down there. I would use 24db slopes at about 800hz to play it safe. I would also measure them on the horns to see how they look. Look at the horn they used on the spec sheet to get an idea of what you need to get them down that low. Can you get new diaphragms if these get cooked??

http://www.jblpro.com/pub/obsolete/2461.pdf

Rob:)

[4343]

Hey folks,

I got a pair of 2460 1" phenolic drivers.... I would like to run them with an active crossover (500hz/12db).
They will be mounted on very short horns, horn lenghts ~20cm and mouth-area aprox 20*20cm...

Is this crossover-point to low ?

Can I run them with full gain ?


Thanks a lot,
Olaf

The rule of thumb I have always used with my 1" drivers is this: If JBL says the horn is spec'ed to 800 Hz, I will not use it below 1600 Hz at full power. I have a pair of 2307's with 2461's on them, and the horn was used down to 1200 Hz by JBL. I have never run them below 2400Hz. They can produce phenomenal volumes with this crossover point and survive. (30 years so far!)

If you do reach maximum power you will know it by the sound of the diaphragm hitting the phase plug, it makes a very annoying popping sound that is your clue to back off on the power! (Don't try this with an aluminum diaphragm, they have been known to just break:crying: at those power levels.)

[Dr.db]

Thank all you guys a lot for those direct and quiek answers of yours!! :)

Allways a pleasure to visit this forum.



All righty, I will look out for a new active-crossover which will cutoff at something around 800hz with 18-24db or 1200-1600hz with 12db...
Could I actually link to active-crossovers in series ?
Because I got two active-crossovers; one will cutoff at 500hz/12db and the other at 800hz/12db...
Or will this be a big mess ?

[Robh3606]

Could I actually link to active-crossovers in series ?


Yes you can. I have done it for years and it works just fine. I have an M552 at 50Hz and use the high output to feed an M553. The M553 has a points at 300 and 1.5K. You cannot use them to try to cover the same crossover point. One as a high pass feeding the second crossover works fine.

Rob:)