Contour Enthusiasts Group Archives Forums Modifications Audio Ohms Questions

Wow, blow up thread!

He has two drivers peopl3. Each driver can be wired into 2 or 8 ohms for most effective use of power. Then the two drivers can be wired in series or parallel for a 1, 4, or 16 ohm load. I was partially incorrect in my first reply. If the amp is stable in stereo with a 2-ohm load, with it that was for most power use. Otherwise, 4-ohm mono is most likely the best route.

And you call yourselves gooroos.

LOL You guys are funny!!!

Just to throw some gas on the flames, has anyone here run a single voice coil on a DVC sub? And, to what results?

Colin
-aspiring car audio guuguu

Yea...I have been away from the audio threads, trying to get info for my newest project. Gonna put the sounds back into the SVT and mod up my newest toy.....more on that later though

APT, an amp that can handle 4 ohm mono is then (almost automatically, barring some crazy mono black amp setup) 2 ohm stereo stable. The amp sees this as the same load. Either way will yeild the same power, depending on box or other varibles (like a crossover with a mono switch) it really wont make a difference.

And to this day JL will still void your warranty for using one coil of a DVC.....doesnt mean it cant be done....just not worth doing it. :p

Don't leave one voice coil unconnected. The speaker is designed to use both. With only one connected, cone travel will be minimal which may result in not enough air movement to cool the voice coils = burn up.

For dual VC 4 ohm subs: Wire up one + to the other voice coil's - lead on each speaker. Take each remaining + lead (one per speaker) on each speaker to the + bridged lead on the amp. Take the remaining - leads (one per speaker) to the - bridged leads on your amp.

For dual VC 8 ohm subs: Wire the + leads together and the - leads together on speaker one. Repeat for speaker #2. Connect the left speaker + and - leads to the left output, the right speaker to the respective right outputs. This will be a 4 ohm stereo load which will leave much more dynamic headroom than an 8 ohm mono load. The Xplode series amps, IIRC (someone correct me if I'm wrong), have a regulated power supply which tend to run better around 4 ohm loads, not above (as in 8 ohms briged).

These are just my opinions from running the installation bay at a car audio shop about 5 years ago and running the IASCA circuit from '90-'93.

Oh no! Here we go again...
:rolleyes: :rolleyes:

Look at what you have done Knu!

You can definitely leave one coil disconnected. JL will void the warranty if you do but not for the reason cited or because of driver failure because of the wiring method. After numerous e-mails between the JL tech support manager and myself, we came to an agreement that it would not hurt the speaker if used properly. Meaning, halving the power handling, re-measuring the specs and then using the correct box for the new parameters. Unless of course you short the other coil which just results in a 3 dB drop in effeciency. Cone travel is not limited, if you only send half the power, the VC will not get hotter, it will function the same way as before with lower effeciency and potentially different t/s parameters. It will not make the subwoofer work harder to move the cone. But it will have to work harder to produce the same output because of the drop in sensitivity.

Now, to add to this slightly, there are very few circumstances where using 1 coil makes sense, so normally, I cannot recommend this method.

Yes, I have used a DVC sub with only 1 coil connected and in my scenario sounded very good and caused no damage to the sub.

Subs fail more from misuse than any other problem. If you've used a sub this way without blowing it, consider yourself lucky.

The magnetic draw will not allow proper voice coil movement because it was designed for power to come thorugh both voice coils. Putting the sub in a larger box designed for one voice coil is a band aid fix until you measurre the new physical and electrical Q of the driver. Anyone know how to do that? Explain it please... and don't quote some box program equation either...

Mr. T asked for a way to wire them up... dnewma04, you did that part by only wiring two VCs, but now you need to tell him how to rebuild his box to fit the new drivers he's created.

I'm sorry Brad, but all I did, originally, was answer a question that someone had on how the audiobahn's could be be used in a 2, 4, and 8 ohm load. I did NOT recommend using 1 VC because it just doesn't make any sense in his case. He should either wire the VCs in parallel and use the amp in 2 ohm stereo mode, or do a series/parallel connection and wire them to the amp with a 4 ohm mono amp.

Now as far as DVC drivers go, if you short the other coil (run a jumper across it) all of the parameters remain the same except for teh sensitivity of the sub will drop by 3dB and the power handling of the sub will be cut in half. You can also add a resistor to "tune" it to a certain Qtc, or better yet, use a variable resistor across the other coil to allow to "dial in" the qtc to your needs. This is especially valuable in a dipole subwoofer or an infinite baffle arrangement where a highish Qtc is desired as it literally determines the Qts.

How would I test the new paramaters? I would first go to the company that produced the sub to get them. If that wasn't an option, I would throw them on hte woofer tester. You can also test them with some basic electronic tools if you have them, but it is time consuming and you need the tools to do it.

I don't consider myself lucky, I consider myself knowledgeable enough to consider all the available options and choose the one best suited for my application, in this case, it was to sacrifice some output for the money savings I desperately needed at the time. I had a couple of options, use the amp I had and one VC, buy another amp, buy another speaker. I chose to keep what I had and it worked very well. Of course, before I made the decision, I talked to a few (4) engineers/designers and received feedback from numerous members of the DIY community with more years building speakers than I have been alive, and they all agreed that it was a perfectly viable alternative. I assume that first sentence of yours was to imply that I "misused" the sub, which is completely wrong. I also didn't recall saying that I just put the sub in a bigger box as a bandaid. I put it in the box it was intended for, in my case a critically damped sealed box.

WHooohooo....it starts again. .....Brad, Dave and I have discussed this till we were both blue in the face (basically you summed up what I had said)......

As for the parameters, get yourself a woofer tester from PE and you can get the specs very easily. I really dont think there is a more practical way to calc all the specs needed.

Edit: Just noticed your response Dave, got to read it then I get back with ya's

Bill, this is all your fault!

Talk to the engineer at Eminence! He is one of the people on my side I even got the techie at JL to agree with what I was saying!

You're right, I'm sorry I jumped all over that point man. I swear, someone put something in my coffee this morning...

I still have a problem with a few things however...

Shorting the second VC eliminates the electromagnetic power created by moving it past the magnets, thus eliminating any resistance created by that coil. That part I agree with... The part I still don't see you correcting is the physical resistance of the driver suspension and the ability to overcome the now double sized magnetic motor. Using the box designed for the speaker using both voice coils won't work correctly and still leaves the VC in danger of being blown... Did I miss something else?