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Please Help! DIY subwoofer doesn't work

1056 Views 25 Replies 8 Participants Last post by Palmtree, Oct 10, 2006

Palmtree

Discussion Starter · Oct 9, 2006

Ok. I couldn't find the patience to veneer the sub before I tried it out. So I decided to put the veneer on the back burner and just painted it flat black for now. For those that don't know--it is the RL-p15 d2 in about 260L with about 15.5Hz tune. The amp is the Behringer EP1500.

I wired the driver in series (+) to (-) and (+) to (-) then to the amp in bridged mono mode. I mean the sub has almost no output, and that is with the gain on the EP1500 cranked to 100% (which shold be 1400 watts)

. I tried flipping different switches on the amp and I made sure that the receiver was set so the speakers were on small and "yes" for subwoofer.

Could someone tell me exactly how the EP1500 should be set up for bridged mono operation. I think I read somewhere that it was labeled backwards or something. Any help is appreciated.

Brett

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Palmtree

Discussion Starter · #2 · Oct 9, 2006

I just realized that I wired it wrong. I ran a wire from the positive post on the cabinet to the positive of VC1. Then I ran a wire from the same terminal (positive of VC1) to the negative of VC2. Then a wire from positive VC2 to the negative terminal on VC1. Then another wire from negative VC1 to the negative post on the cabinet.

Could I have hurt anything while trying to get this thing going last night?

I feel like such an idiot

.

here is how I wired it

http://imageshack.us http://img326.imageshack.us/img326/5...gwiringuy7.jpg

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SteveCallas

· #3 · Oct 9, 2006

You want one positive lead from the amp going to the positive lead on VC1. You want the negative lead from the amp going to the negative lead on VC2. Then you want a wire going from negative on VC1 to positive on VC2.

From your post, I'm not sure if you have resolved the problem or not did you? It's always best to double and triple check everything. I realize that as completion nears, you probably wanna test it out asap, but that's when mistakes will creep in. Also, realize that you aren't amp limited with 1400 watts - if you don't approach reference levels, you should be fine though.

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jonathanb3478

· #4 · Oct 9, 2006

So, you wired them in parallel, but out of phase.

You just gave the amp a 1ohm load, then maxed the gain. I am sure those voice coils got quite a workout, just in exact opposite directions.

Wow.

So, assuming the driver still works (no rattling during normal operation or burnt smell), and the amp still works (no tripped fuses or blown output device), you seem to have gotten lucky.

Hopefully sending a "home audio standard" line level output into a "pro audio standard" line level input worked in your favor, in this instance.

Also, setting the gain nob to max does not give you 1400 watts. It could be asking the amp to try to put out 5000 watts, or 30 watts. It all depends on the voltage the amp is seeing from from the gain nob and what amount of gain the amp has, natively (gain nob bypassed).

Good luck!

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Palmtree

Discussion Starter · #5 · Oct 9, 2006

Quote:

Originally Posted by SteveCallas
You want one positive lead from the amp going to the positive lead on VC1. You want the negative lead from the amp going to the negative lead on VC2. Then you want a wire going from negative on VC1 to positive on VC2.

From your post, I'm not sure if you have resolved the problem or not did you? It's always best to double and triple check everything. I realize that as completion nears, you probably wanna test it out asap, but that's when mistakes will creep in. Also, realize that you aren't amp limited with 1400 watts - if you don't approach reference levels, you should be fine though.

I think I figured it out. I think it should be wired like this

http://imageshack.us http://img405.imageshack.us/img405/3...tseriesuh3.jpg

Yeah I know it's not the best amp for this setup. But I already had the amp and I didn't want to go dual 4 just in case things change in the future. Tt just seems like a 4 ohm subwoofer is more flexible than 8 ohm or 2 ohm. And you are right about the rush at the end. It was Sunday afternoon and I promised the kids we would watch a movie in the new room. So we ended up watching the movie with no subwoofer

.

Do you think I could have damaged anything? Thanks again for your help Steve.

Brett

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Palmtree

Discussion Starter · #6 · Oct 9, 2006

Quote:

Originally Posted by jonathanb3478
So, you wired them in parallel, but out of phase.

You just gave the amp a 1ohm load, then maxed the gain. I am sure those voice coils got quite a workout, just in exact opposite directions.

Wow.

So, assuming the driver still works (no rattling during normal operation or burnt smell), and the amp still works (no tripped fuses or blown output device), you seem to have gotten lucky.

Hopefully sending a "home audio standard" line level output into a "pro audio standard" line level input worked in your favor, in this instance.

Also, setting the gain nob to max does not give you 1400 watts. It could be asking the amp to try to put out 5000 watts, or 30 watts. It all depends on the voltage the amp is seeing from from the gain nob and what amount of gain the amp has, natively (gain nob bypassed).

Good luck!

Actually, there was no anything. No smells, no noises--no anything. I will rewire it tonight and keep my fingers crossed. Thanks!

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Palmtree

Discussion Starter · #7 · Oct 9, 2006

What does wiring out of phase do in this situation? I understand the 1 ohm load is hard on the amp. But what does wiring out of phase do to the driver?

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SteveCallas

· #8 · Oct 9, 2006

Quote:

What does wiring out of phase do in this situation? I understand the 1 ohm load is hard on the amp. But what does wiring out of phase do to the driver?

If it didn't sustain any damage, what might have happened would actually be funny. If equal power was fed to each coil, I'd imagine they would have cancelled each other out perfectly, leaving the cone completely inert. With the lack of actual movement and the increasing of power, those coils would have probably heated up quite a bit.

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Palmtree

Discussion Starter · #9 · Oct 9, 2006

Quote:

Originally Posted by SteveCallas
If it didn't sustain any damage, what might have happened would actually be funny. If equal power was fed to each coil, I'd imagine they would have cancelled each other out perfectly, leaving the cone completely inert. With the lack of actual movement and the increasing of power, those coils would have probably heated up quite a bit.

That would explain it. I even touched the cone and there was very, very little to NO movement. I sure hope I didn't fry the coils. Will there be any visual evidence if I did damage the coils? I mean when I take the speaker out to rewire it--should I see anything different?

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soho54

· #10 · Oct 9, 2006

If you cooked the coils your nose will tell you.

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Palmtree

Discussion Starter · #11 · Oct 9, 2006

Quote:

Originally Posted by soho54
If you cooked the coils your nose will tell you.

Well that is good because I didn't smell anything. And neither did my wife and she has the nose of a bloodhound--especially sensitive to smoke.

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Newfiestang50

· #12 · Oct 9, 2006

Quote:

Originally Posted by Palmtree
I just realized that I wired it wrong. I ran a wire from the positive post on the cabinet to the positive of VC1. Then I ran a wire from the same terminal (positive of VC1) to the negative of VC2. Then a wire from positive VC2 to the negative terminal on VC1. Then another wire from negative VC1 to the negative post on the cabinet.

Could I have hurt anything while trying to get this thing going last night?

I feel like such an idiot

.

here is how I wired it

http://imageshack.us http://img326.imageshack.us/img326/5...gwiringuy7.jpg

Don't worry, you did not do any damage wiring it this way since the + and - of your amp did not actually see any load what so ever since there was actually no complete circuit in this configuration.......this is why there was no cone movement or sound........you basically just extended your speaker wire by using the voice coils of you sub thus the terminals (+ and -) of VC2 had full potential of your amp just sitting there when you had the gain turned to max.

To wire coils in series :

-> + of Amp to + of VC1

-> - of VC1 to + of VC2

-> - of VC2 to - of Amp

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Palmtree

Discussion Starter · #13 · Oct 9, 2006

Quote:

Originally Posted by Newfiestang50
Don't worry, you did not do any damage wiring it this way since the + and - of your amp did not actually see any load what so ever since there was actually no complete circuit in this configuration.......this is why there was no cone movement or sound........you basically just extended your speaker wire by using the voice coils of you sub thus the terminals (+ and -) of VC2 had full potential of your amp just sitting there when you had the gain turned to max.

To wire coils in series :

-> + of Amp to + of VC1

-> - of VC1 to + of VC2

-> - of VC2 to - of Amp

Thanks--that makes me feel much better--and makes sense too. I will change the wiring tonight and report back in the morning.

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Newfiestang50

· #14 · Oct 9, 2006

Quote:

Originally Posted by Palmtree
Thanks--that makes me feel much better--and makes sense too. I will change the wiring tonight and report back in the morning.

Sorry, but please ignore my above assesment......I must of had a brain fart........you actually wired the coils in parellel and out of phase so your amp actually did see a 1 ohm load which is getting extremely close to a short circuit.

The second part of my post explaining the correct wiring for series connection is valid....sorry for the confusion.

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Palmtree

Discussion Starter · #15 · Oct 9, 2006

Quote:

Originally Posted by Newfiestang50
Sorry, but please ignore my above assesment......I must of had a brain fart........you actually wired the coils in parellel and out of phase so your amp actually did see a 1 ohm load which is getting extremely close to a short circuit.

The second part of my post explaining the correct wiring for series connection is valid....sorry for the confusion.

You couldn't just let me fell OK about my screw up huh. Just kidding--although I did like your first post much better. Either way, I will rewire it tonight and see how much damage I have done. By the way--why didn't the cone move when wired that way?

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SteveCallas

· #16 · Oct 9, 2006

Man, I dunno about you Palm, but I can smell that burnt coil from here

Again, if the coils were seeing equal power, their forces would have cancelled each other out, resulting in no movement, but very hot coils.

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Palmtree

Discussion Starter · #17 · Oct 9, 2006

Quote:

Originally Posted by SteveCallas
Man, I dunno about you Palm, but I can smell that burnt coil from here

Again, if the coils were seeing equal power, their forces would have cancelled each other out, resulting in no movement, but very hot coils.

Oh thanks! That makes me feel much better

. Seriously though--I am really pretty scared about this. The Boss (wife) already told me to forget getting a new driver if it is ruined.

Steve I think you live in St. Louis so you might even be able to hear my cries tonight. Keep an ear perked to the southwestwest at about 9:30

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J. L.

· #18 · Oct 9, 2006

Quote:

Originally Posted by SteveCallas
Man, I dunno about you Palm, but I can smell that burnt coil from here

Again, if the coils were seeing equal power, their forces would have cancelled each other out, resulting in no movement, but very hot coils.

I don't have a specific post to cite, but a "knowledgable" loudspeaker designer had posted on one of the boards I follow that most of the power we send to our subwoofers is wasted as heat, and very little is actually used to move the cones. (they are very inefficient devices)

As such, the heating of the opposing coils was probably within 10 percent of that when wired correctly. The correct wiring does not "magically" cause the voice-coils to heat up less. It does cause the cones to move more since the movement forces are in phase instead of in opposition. Now, the movement of air does allow some cooling of the coils, but not that much.

So, unless the amplifier gain was maxed out, and the amplifier power output greater than the "thermal" power rating of the sub for an extended period of time, odds are everything will be fine. (You would smell the glue and insulation burning it it was really bad)

Joe L.

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steve nn

· #19 · Oct 9, 2006

To wire coils in series :

-> + of Amp to + of VC1

-> - of VC1 to + of VC2

-> - of VC2 to - of Amp

____________________________________________________________

Maybe a pic would be of help.

Don't worry Brett, some of us are just destined to learn the hard way... I feel your pain br.

http://i3.photobucket.com/albums/y75...hmDVC_4ohm.gif

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jonathanb3478

· #20 · Oct 10, 2006

I am sure he has a handle on the correct wiring by now, I would just like to know if everything worked.

I would think it did, mostly because he indicates that through the whole thing he could "barely" feel movement from the cone. This tells me two things:

1. None of the structure of either voicecoil of the driver failed (driver should be ok), as that one would quit canceling the other.

2. Amp never failed, as he did feel "some movement", which was just the difference between the output of the two voicecoils splitting the same signal. This tells me the amp never failed.

Pointing this out earlier would probably have helped the blood pressure of the poor OP.

I really think the "consumer level" output into a "pro level" input saved his @$$ in this case. That amp was ready to cook output devices, and the driver's thermal limits could have been easily exceeded under the right circumstances with these components with this wiring.

Obviously, I do not believe this happened to the OP, and I hope to read him say this in the near future.

I will also say that he was not killed or even injured (pride does not count

), and he did not destroy any property. That makes this a very valuable learning experience that cost him nothing.

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