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Anybody Clamshell with different companys? (Read 2770 times)
buggers
Ex Member



Anybody Clamshell with different companys?
09/20/06 at 12:30:51
 
I have a pair of JBL L112's from the early 80's and a pair of Infinities from the mid to late 80's and I was wondering if any of you have clamshelled the HK with drivers from different companies ??? Thanks.
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musgofasa
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Re: Anybody Clamshell with different companys?
Reply #1 - 09/20/06 at 20:12:32
 
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
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Adrian D.
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Re: Anybody Clamshell with different companys?
Reply #2 - 09/21/06 at 11:12:57
 
never clamshell diffrent drivers. never clamshell a driver and a pr.
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musgofasa
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Re: Anybody Clamshell with different companys?
Reply #3 - 09/21/06 at 15:18:08
 
[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
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buggers
Ex Member



Re: Anybody Clamshell with different companys?
Reply #4 - 09/21/06 at 17:47:44
 
I think I need to clarify a bit. I have 2 JBL drivers for one clamshell, and 2 Infinities for the second clamshell to go into the same box. Are you saying not to do this, or are you saying not to make a clamshell of say 1 Infinity and 1 JBL?
This is confusing me and I'm the one typing it Undecided
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musgofasa
Ex Member



Re: Anybody Clamshell with different companys?
Reply #5 - 09/21/06 at 18:05:26
 
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
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Jet-Lee
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Re: Anybody Clamshell with different companys?
Reply #6 - 09/21/06 at 19:05:24
 
When you clamshell the speakers, you're essentially making them one speaker, right? Now, consider each pair its own speaker, so you've got 1 JBL and 1 Infinity. Now your question is, "Should I iso-load my HWK with two different drivers?" because that is essentially what you're doing.

I think the same rule applies as Rob's first post. Something's gonna blow. Sure, they're not clamshelled, but they're still iso-loaded and still having the wrong effects on each other.
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« Last Edit: 09/21/06 at 19:06:29 by Jet-Lee »  
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musgofasa
Ex Member



Re: Anybody Clamshell with different companys?
Reply #7 - 09/21/06 at 20:36:58
 
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
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buggers
Ex Member



Re: Anybody Clamshell with different companys?
Reply #8 - 09/22/06 at 13:10:25
 
The one concern I had was that one set would blow a larger volume of air and maybe blow it up or something so I'm gonna stick with using the 2 JBLs I have and later buying something better to put in the puppy. Thanks guys for your help.
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musgofasa
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Re: Anybody Clamshell with different companys?
Reply #9 - 09/22/06 at 14:20:26
 
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
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Adrian D.
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Re: Anybody Clamshell with different companys?
Reply #10 - 09/22/06 at 17:42:08
 
diffrent drivers moev a bit diffrently on the same signal. i'm not implying it's a night and day diffrence, but it's enough to muddy the bass and make a good enclosuse sound like chit.
if you have the drivers, try it. and make sure you report back.
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Buggers
Ex Member



Re: Anybody Clamshell with different companys?
Reply #11 - 10/24/06 at 20:25:18
 
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.
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