Do 2" driver require equalization?

[scorpio]

Hi all,
I have another question related to the possible change from a 1" driver (LE85A) to 2" driver in my current set up. The 2" would probably be 2446 or 2450. I'm concerned about the very irregular response curve that these two drivers show on their datasheet, with a sloping response curve that spans almost 10 dB from 500 to their max efficiency, as well as the ragged response above 10kHz. This looks pretty bad when compared with the rather flat response of the the 2420/LE85. I plan to use the driver from 600Hz up to where I can cross it with my 2405 (probably in the 8-1OkHz range) with a yet to be defined crossover (first or second order). I also use a 2nd order line level filter between preamp and power amps (SS on bottom, SET on top) currently feeding the LE85 directly.

Does this irregular response mean that I'll have to use additional equalisation in the midband to flatten the overall response? Or it one of these case where the problem is more of a good combination between the driver and the horn? (I'm using LeCleach' profile circular horns).

I'm worried that this move up the ladder will mean at lot of tweaking and hassle before reaping the expected benefit of the bigger driver.

Any clue?

Thanks

[Zilch]

I am using 2450 (with SL diaphragms) on 2380A from 800 Hz to 7 kHz without equalization. Tweeter is 2407H on 1" PT-F95 waveguide. Crossover is the "Keeper" we developed in these forums. There's also a more recent 8.5 kHz version of that for use with the slot tweeter:

http://audioheritage.org/vbulletin/showthread.php?p=130246#post130246

I chose 2450 because the response was flattest in that region. In theory, it should require a bit of EQ, but in practice, it doesn't, to the best that CLIO and I have measured, using my particular combination of drivers and horns. You're going to have to measure the response on your own horn for a final determination....

[Robh3606]

That all depends on the horn.

http://www.lansingheritage.org/images/jbl/specs/pro-comp/2446/page2.jpg

http://www.lansingheritage.org/images/jbl/specs/pro-comp/2450/page2.jpg

Both of these data sheet pages show the response on a 2380 and in both cases the curve in the response is clearly visible. The 2380 is a biradial and requires compensation for flat on and off axis response. The plane wave tube responses are typical compression driver curves.

If you use another horn such as an exponential you may or may not need compesation for flat on axis response. The flair type will determine what and if any compensation is needed and what your ultimate response will be in the 10-20K range.

Take a look at this excellent thread started by Jack. I think it may go a long way in answering your questions.

http://audioheritage.csdco.com/vbulletin/showthread.php?t=12967

Rob:)