isobaric 6.5" subs in a small sealed enclosure?

[johsti]

Hello,

I have 2 older jlaudio 6.5" subs (4ohms SVC). They are in good condition and just sitting around taking up space. I also have some 3/4" mdf taking up space.

I have made some sealed car audio enclosures with mdf and fiberglass, but that's about as far as my speaker building experience goes.

what do you guys think about running the 2 6.5"'s in an isobaric configuration? I'm sorry, I don't know the specs on the speakers. I looked on winisd and modeled them based on the JLaudio 6w1. I could be way off, but thought I could start there.

I know nothing about isobaric. How would I wire the speakers (out of phase?)? How powerful of an amp would I need? I was looking at some plate amps at PE.

I'm looking at this project as nothing more than something to kill time, and learning something new. My expectations are low, but if I can make a decent little sub for music listening I would be happy.

Any insight, input, advice is appreciated. I would like to put these speakers to use rather than trashing them. In the meantime I will continue to search the forum.

Thanks

 

[Sheep]

I would make 2 separate subs and have stereo subs. Pair them with some bookshelfs, and you would have great music extension.

Isobaric isn't a great enclosure design(Pinnacle uses it).

SheepStar

 

[zumbo]

I would wedge both subs in a down-firing rear-ported design with the coils wired in series for two 8ohm loads. Then parallel (strap) to a healthy 4ohm stable amp.

 

[annunaki]

I agree with the ported enclosure design. Tune them as low as they can go, around 30hz or so. Roughly a .75 ft^3 enclosure with a 2.0" port 11.1"long. I would recommend against wiring the subs in series, as JL does not recommend it with their woofers. I would find a solid two channel 4 ohm capable amplifier like the Behringer A500 for running them (150 RMS x 2). This would give you some linear solid low end from very little space. In a small room at least.

 

[zumbo]

My bad. I thought I read 4ohm DVC. OOPS! That is why I said to wire the coils the way I did. annunaki is correct.

 

[johsti]

I like the idea of a down firing ported enclosure. Should I make one enclosure, or one enclosure with each woofer separated in its own chamber with 2 ports. I have no specs on these speakers, so where should I start with this enclosure? Will .75 ft^3 be enough like annunaki suggested?

One more question. This will be used in a 2 channel setup for my computer. Right now it consists of a 15 year old Onkyo stereo receiver, a pair of athena S.5's, and a sony wm500 12" front firing sub. This setup works great for listening to mp3's on the computer, however, the sub is on its last leg. I was wondering if I can run the dual 6.5" subs off of the onkyo receiver? There is A/B speaker zone option on the receiver. I was thinking of powering the subs on zone B, and the speakers on zone A. Can I get a bass coil/blocker with a frequency cutoff around 100-120Hz as a crossover for the subs? Will I need more power to drive them. The amp is rated at 100 watts x 2. It definitely has some juice.

 

[annunaki]

I modeled the JL Audio 6W0-4 on WinISD. The .75 ft^3 enclosure tuned to 30hz was the best looking enclosure for the sub. That is the enclosure I would do if they were my woofers. You could make one enclosure with two chambers and ports if you wish, or one enclosure 1.5ft^3 (after displacement) with a 3" port 11.9" long.

I would recommend against using a coil as a crossover for sub woofers if you can at all help it. They suck up loads of power due to their lack of efficiency. If you can cross them over electronically it would be much better. 100 watts per sub should be plenty.