Never done it in a HWK, but I have done it in other 6th order boxes for cars. I would have to say that I very highly discourage the practice. My experience was from stubborn customers with very thin wallets and doing what I was paid to do resulted in bad sound and blown woofers. Of course this could be mostly due to ignorant customers who crank amp gains and volume knobs as much as to the drivers themselves. To say the least, I have had far better results clamshelling drivers of the exact same manufacture and model and even better results when testing several woofers with the same manufacturers specs to the closest test results before clamshelling. That being said bear in mind that I would even test the amp outputs at a given input voltage and match the gain outputs before continuing with most of the install. The better matched everything was,. the clearer and resultingly louder the install would play.
Now, I believe someone will shoot holes in my theories, but those were my general experiences over the last couple of decades.
Good luck with the HWK btw let us know how it sounds!

Robert

[quote author=Adrian D.  link=1158755451/0#2 date=1158833577]never clamshell a driver and a pr. [/quote]


LOL,
Never tried that one, but it sounds like a bad idea to me!

Robert

Ahhhh,

I would definitely stay away from  1 Jbl/1 infinity

Here is the deal. I don't think anything will blow up with 2 brands in the same enclosure, but I think it might be a waste to be honest. That's a lot of box to build for 4 woofers when you could get more out of 2 or 4 boxes.
I just read a thing from JBL about room placement of subs to get even dispersion and they said that the optimum placement for almost any "rectangular space" was one sub in the center of each wall. I thought that was interesting.
That being said, there is something to go for one enclosure with more power on it. It isn't something I would do personally, but then again, I wouldn't do a lot of things that some do every day lol. (bungee jumping comes to mind)

I won't say "don't do it" because there may be very good reasons to go ahead with it, but for me, it would be one of the two pairs only and reserve the other pair in case the first ones lie down on you.
My 2 cents lol.

Either way, let us know what you decide and how it sounds!

Robert

I guess the best way to look at it is this:

one sealed chamber with two holes cut in the front;
JBL on the left with xmaxx......
Infinity on the right with xmaxx......

When the speaker with the greater xmaxx moves further into the chamber in phase with the other that is moving at the same time the air spring tries to force the weaker driver to move the wrong way.

things start to happen when putting undue stress on a driver cone.

At least that is one reason I don't like the idea.
I don't like clamshell ISO loading for the same reason even if the drivers are the same. When you test two speakers, they specs usually prove that they aren't as close as the manufacturers specs lead you to believe. There is always a tolerance.

That being said, the only question is what is your tolerance for this happening? If you don't care and it produces more or better noise, you can whack away at it. If you do, I think it is better safe than sorry.

Robert

I think the only time this would be a real concern is at high SPL levels or max output levels. Albeit, if you are building a HWK I think this would mean it is a concern lol.
Sounds like a wise decision. Say if you don't want either set of those woofers, I could be in the market  ;)

I have had some good experiences with both brands and Chris was a good friend for many years while I was in the industry.
(Makes a person Bias ya know)

Good luck!
Let us know how it turns out!

Robert

Well, I built the little puppy and put in my vintage, early eighties, 12 inch JBL's and then gave them a little test drive. The drivers obviously needed no break in. The sound, I must say, was quite disapointing. These drivers are very inefficient and require a lot of juice to get them making some noise. So I am going to pick up a couple of Infinity Kappa 122.7W's which have an FS of 18, sensitivity of about 20, and go as low as 18-23 depending on where you look. Hopefully these will work better in this cabinet and make my home theater sing!!
I'll let you know how it turns out.