actually, I'm not 100% clear on what JL is specking the dc resistance at, but remember that a multimeter is measuring the dc resistance at the speaker, no the impedance. They spec it at 2.45 or something like ohms, I will guess that is with the coils wired in series, since they claim that in parallel its divided by a factor of 4. I assume you would no if something is wrong if it measured .625. But I dont think you wired in parallel instead of series. How did you wire it in series. Did you go put a wire from the black or negative of one coil to the positive or red of the other coil. Then I assume you connected your positive connection to the remaining positive from the one coil and negative from the other.
Maybe it is just an issue with the box, but again, I dont see how you could be so massivly dissapointed with its output to think that something might be wrong. If you think something is wrong, the output is that bad, then I question if something is wrong. Again, what are you using to test it with, what sorts of material?
As for box sizes. I came up with 4.35 cubic feet for a sealed box. In room it will easily realise 20hz, with very low distortion, and very good output. I came up with 8.85 cubic feet for vented with a 4"x8.66" or so. In a 5 cubic foot box, you a get a rise in the response at the lower end, but would work with a 4"x17.6" box.
Maybe it is just an issue with the box, but again, I dont see how you could be so massivly dissapointed with its output to think that something might be wrong. If you think something is wrong, the output is that bad, then I question if something is wrong. Again, what are you using to test it with, what sorts of material?
As for box sizes. I came up with 4.35 cubic feet for a sealed box. In room it will easily realise 20hz, with very low distortion, and very good output. I came up with 8.85 cubic feet for vented with a 4"x8.66" or so. In a 5 cubic foot box, you a get a rise in the response at the lower end, but would work with a 4"x17.6" box.
I am trying the same type of setup,i.e. using a car subwoofer for HT use (Image Dynamics IDSPL 15"). I am waiting to receive some bigger amps before I decide if this experiment will work. I have the subwoofer mounted in a sealed box. I tried using a 400 w. amp but had poor results. I'll see what an honest 1200w. does in the near future. If this doesn't work out I'll be looking for a pair of more HT oriented subs.
That's certainly not the feedback I wanted to hear, lol. Thanks for your reply, just the same. If these car subs have such low Fs how do they not play low in a HT or 2 channel setup. Is this because of the cabin gain when the manufacturer did the specifications? In the particular case of the IDSPL and somwehat for the JL subwoofer, these were built for massive SPL at low frequencies. I am not understanding something in this so bear with my ignorance about this.Stupify said:
The t/s parameters are not easily available. As Stupify has said, they were custom built for the ID team. The one I have is basically, a double stacked magnet on an IDQ cone and stamped frame. It looks as the cone may have had some tratment. I called ID and got some info but it was inaccurate and no TS. If I had the eqipment I would measure it. I don't mean to hijack this thread about the JLw7 that the OP started as that is one heck of a subwoofer, albeit for car audio. In relating to this use , I wondered if all car audio subs are not workable into a home environment? If the proper enclosure is built and the large amount of watts is delivered I don't know why they couldn't be used.simon5 said:
to the orginal threadstarter
As others have mentioned I believe you have wired the sub up wrong! I dont care what your multimeter says, if it's not hooked up positive-negitive in series the coils will oppose eachother and cancel out(however the dc resistance will be the same as if the were wired up right). You might hear a little sound with the amp cranked up to the max, but it wont be hardly anything.
Try this:
hook up only one coil to the amp and keep the gain below half, my bet is that things improve alot here. If they dont, something is seriously wrong... If it works better, then wire up that second coil and make sure its positive-negitive-positive-negitive.
positive-positive/negitive-negitive is only for parallel!!!!
As others have mentioned I believe you have wired the sub up wrong! I dont care what your multimeter says, if it's not hooked up positive-negitive in series the coils will oppose eachother and cancel out(however the dc resistance will be the same as if the were wired up right). You might hear a little sound with the amp cranked up to the max, but it wont be hardly anything.
Try this:
hook up only one coil to the amp and keep the gain below half, my bet is that things improve alot here. If they dont, something is seriously wrong... If it works better, then wire up that second coil and make sure its positive-negitive-positive-negitive.
positive-positive/negitive-negitive is only for parallel!!!!
I would try this but am worried about the space requirements, i.e. how large would the final TL enclosure be? I would think, if using a 15" driver the enclosure would be quite large. Do you have a link to an enclosure using a large car audio subwoofer? Thanks for the help, BTW.Volenti said:
westend said:
Oh it would be large, ~18cuft in volume and ~11' long if you made it straight.
This is the TL I'm using with a cheap car sub it's only 8' long though.
An externally hosted image should be here but it was not working when we last tested it.
AndrewT said:
Well both will require large volumes to get really deep, I modeled a sample high Q 15'' in both a large low tuned vented and in a TL and the TL had gains across a large bandwidth while the vented only has the typical gain around the tuning frequency, in essence the TL does a better job in a similar volume of space.
One thing to look out for in straight TL's in particular is that they can sometimes play havoc with room modes, since the driver and opening are so far apart they can excite different room modes, folding the line avoids this though.
I apologise for bringing this thread back up, but I've got a 13W7 in a 5.7cu.ft enclosure tuned at 18hz with a 100sq inch slot port.
I definitely do NOT lack lowend whatsoever...and this is with only 300wrms @ 4ohms from a plate amp, I can only imagine what this would sound like with 1.2kw on it. As for musicality, the subwoofer is really good...would say 30:70 Music/HT.
If anything I'd say instead of selling your sub off, I'd make a new enclosure.
I definitely do NOT lack lowend whatsoever...and this is with only 300wrms @ 4ohms from a plate amp, I can only imagine what this would sound like with 1.2kw on it. As for musicality, the subwoofer is really good...would say 30:70 Music/HT.
If anything I'd say instead of selling your sub off, I'd make a new enclosure.
Put me into that "all" category. I mounted the car sub in the box and couldn't get anything out of it, no matter what kind of wattage pushed at it. Pulled the sub out and checked my wiring, all looked good- red to black and two wires from red and black (series wiring to a DVC sub)... hmmm.BassAwdyO said:
Pulled the wires off and checked the polarity with a six v. battery. Whadayaknow, the terminals were miscoded and I had wired it out of phase. Rewired and now all is good. Iwas apprehensive about using a car sub but if you can get past the use of big wattage they play excellent.
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