803B frequency response

[kevin@kab]

Hi,
I am new to this board, but glad I found it.
I have recently scored a pair of 803B's with 291-16A drivers.
I have worked with my own multicells in the past built a 2x2 multi cell mid from wood. My question is, what is the realistic useful HF limit of the 803B? I would cross the bottom at 350hz 24db/oct. But need to know where to roll off the top. Does anyone have any data on this? Thanks.
Kevin
Nov 8, 2010

[SOOTSHE]

I think the limit will not be with your multicells but with the drivers.
A 291 should go out to about 13K.

Forum members with more knowledge of this combo will chime in to assist I'm sure.

Welcome to the board Kevin & good listening with your combo.

[LICORNE]

Hi,
I am new to this board, but glad I found it.
I have recently scored a pair of 803B's with 291-16A drivers.
I have worked with my own multicells in the past built a 2x2 multi cell mid from wood. My question is, what is the realistic useful HF limit of the 803B? I would cross the bottom at 350hz 24db/oct. But need to know where to roll off the top. Does anyone have any data on this? Thanks.
Kevin
Nov 8, 2010

PROTECTING COMPRESSION DRIVERS. You can roll off at 300 HZ with proper protection
Check Atlas sound document on this.The 291 goes to 15 KHZ . If your going to add an extra driver from 13 KHZ to 20 KHZ. then you must cinsider this :"I don't see any point in doing so".
If you want more SPL well use your 291 to 5600 HZ and then add a 288 to 16 KHZ.
This is a trade secret . Of course you will need another set of 803B.

Enjoy

[kevin@kab]

Thanks for the response,
It is going to be interesting to finally listen to these up close.
My 2x2 has been a satisfying horn for over 30 years, built in 1980. I flared that at 250hz with a 1824 driver. I know it is not perfect, but these produce a very solid center image- which I prefer. If the 803b horn can truly be uniform to 13K, that would be something. Right now, I follow the decade rule and roll the top off at 3500hz and use a tw-35 for the top.
One followup question would be about crossover cutoff rates. It seems to me that since I went to 24db/octave, the cross over points seem less seamless between horns. is there any rule of thumb regarding that?

Kevin
Nov 9 2010

[LICORNE]

A 12 DB slope would be better . THe 3500 XO point is excellent.You could add an extra tweeter
per cabinet .

Enjoy

[Panomaniac]

Well my 803 291 combos sure didn't go very high. 7K maybe. The 288 'frams extended that some, perhaps. Use them with a tweeter, I say.

[kevin@kab]

Yes, I am going to keep things pretty much as they are crossover wise and keep the TW35 for the top. so that will cross at 3500 24db/oct. but as you suggest I may be able to extend the top some in the 803 maybe to 5Khz. I have a follow up question on drivers. these 291-16A drivers actually measure 8 ohms. So I presume that means the diaphragms have been changed. Is there anything in particular I should check? I have seen discussions about phenolic vs metal diaphragms for example.

thanks again
Kevin
Nov 9 2010

[kevin@kab]

Here is a picture of the current 4 way system
[IMGLINK]http://www.kabusa.com/gif/horn.jpg[/IMGLINK]
tw35 tweeter
4 cell 2x2 mid 1824 driver
3 cell hyperbolic mid bass with morel 6" driver
folded bass horn ala olson, 10" vifa dual voice coil bass cone.
the 803B should fit nicely on top of the mid bass horn.

Kevin
Nov 10, 2010