2405 crossover point

[Sootshe]

Yes, I know the recommended crossover for the 2405 is 7K.....but can I safely run this driver at 6K with an 18db slope. If so this will save me having to change my crossover, as I don't really want to invest more dollars in that area. Most listening is at what I would call normal, sane levels......80-90db. I do occassionally crank it up for short bursts (1-2 minutes) at 100-105db.
Mid range is Altec 288 with 805 multicells.

Many thanks,
John

[pos]

Hello,

If you are using a passive crossover designed for another tweeter, then you will have to check its topology and compare the impedances curves of the old tweeter and the 2405 to predict the crossover point you will actually get with the 2405 in place.

[Sootshe]

Hello,

If you are using a passive crossover designed for another tweeter, then you will have to check its topology and compare the impedances curves of the old tweeter and the 2405 to predict the crossover point you will actually get with the 2405 in place.

Appreciate your comments, but this is way over my head to calculate. I've attached some info on the crossover that I'm using & can tell you that this is replacing an APT200 tweeter.
Everything sounds OK, in fact, it sounds great. I am just concerned that at high levels I may damage the 2405.

[Sootshe]

....and here's some info I found on the APT 200.
It's an 8 ohm driver.

[yggdrasil]

Try it. You will probably give up before the driver....

But beware that it sounds much better when crossed over around 10K.

[pos]

looking at the impedance curves of a 2405 and the apt200, it seems they are close enough around 6khz, you should be good.
I don't think you will damage your tweeter, but you sure could get it to sound better if crossed higher.
Maybe you could try to find a 076/2403 to replace the 2405. It has a larger diaphragm and a longer horn, and is crossed at 5khz in the L220, so that looks like a logical choice in your case.
They are pricey tho...

[macaroonie]

Surely the limiting factor with the 2405 is the behaviour of the diffraction horn and not he motor. The 2402 bullet will play down to 2.5 - 3 KHz with no adverse effects even in SR applications.

http://www.jblproservice.com/pdf/Cab...ries/4602B.pdf

Having said that I run my 2405's active down as low as 6.5 - 7 KHz admittedly with active drive 24 dB/ oct. seems to sound better that way.

[Allanvh5150]

I agree with Macaroonie. Cross over at 10K. The 2405 will play a lot lower of course but the horn is optimised for 7K +. At 6K you may not notice much of a difference anyway. I do not think that 6k will damage the driver in any way.

Allan.

[martin_wu99]

Yes, I know the recommended crossover for the 2405 is 7K.....but can I safely run this driver at 6K with an 18db slope. If so this will save me having to change my crossover, as I don't really want to invest more dollars in that area. Most listening is at what I would call normal, sane levels......80-90db. I do occassionally crank it up for short bursts (1-2 minutes) at 100-105db.
Mid range is Altec 288 with 805 multicells.

Many thanks,
John

It seems JBL's UHF drivers can be used at very wide range,just like my 4628's 2404,it even can work at 3K.as long as you can accept its sound quality.

[Sootshe]

Thanks guys,
Think everything will be fine......I'm really enjoying the sound of these slots.