Need subwoofer help

holdsworth · Posted: Jun 27, 2011 1:34 pm Post subject: Need subwoofer help

We just got JL speakers all around in the boat. Everything sounds perfect except for the subwoofer. We didn't replace the amps that were in the boat. They are the stock Clarion 2/3/4 channel 400w amp running the boat speakers and a Sony 4/3 channel 600w amp running the tower speakers and the subwoofer. The sub is bridged across the rear channels and the tower speakers on the front two. The sub is getting power, but it isn't hitting hard at all. With all of the other speakers turned off from the fade, I can faintly hear the sub and I can't understand why. All of the wires are hooked up correctly and I checked the RCA plugs running from the amp to the head unit and nothing changed. We had this same problem with the sub that was in there before and have no clue why. Any help is appreciated!

jjaszkow · Posted: Jun 27, 2011 5:46 pm Post subject:

Could be a number ofnthings. Is the sub a dual voice coil sub? If these are misfired, symptoms will be similar to what you describe. Does the amp have a high pass filter? Maybe it is turned on, passing the exact opposite frequencies that the sub is meant to reproduce.

holdsworth · Posted: Jun 28, 2011 5:45 pm Post subject:

SVC, and the high pass filter is on but only for the front channels and the low pass is on for the sub.

m_lesney · Soul Rider Joined: 22 Feb 2008 Posts: 358 City: Austin

you checked the settings on the stereo? I replaced my batteries and expierenced those same symptoms and it was just settings in the stereo.

PimpinD2 · Posted: Jun 29, 2011 4:09 am Post subject:

I think i had the same amp for my Jl 10" sub. It was terrible. I had to turn the Input level control (gain) all the way up. I swapped it out for a small 2channle JL amp. That sony amp is only putting out ~140w rms when bridged and that is assuming sony didnt over rate their amp.

Try messing with the input knob (gain) and turn it up maybe 3/4 of the way. Also i dont remember if it has Freq setting but turn it to around 80hz.

holdsworth · Posted: Jun 29, 2011 4:56 am Post subject:

The gain is all the way up, the subwoofer control on the stereo is all the way up at +6. I looked for more controls everywhere on my head unit and got nowhere with it. I'm thinking I need to make a trip to the audio place this week and pick up a 500w mono amp to power this thing and be done with it.

PimpinD2 · Posted: Jun 29, 2011 7:13 am Post subject:

is it the marine JL amp?

PimpinD2 · Posted: Jun 29, 2011 7:13 am Post subject:

sorry marine jl sub? the 10" white one?

holdsworth · Posted: Jun 30, 2011 9:00 am Post subject:

Yeah it's the 10" JL Marine sub.

PimpinD2 · Posted: Jun 30, 2011 9:21 am Post subject:

That sub is only rated for 250w rms, 500 might blow it

holdsworth · Posted: Jun 30, 2011 6:18 pm Post subject:

It's only putting out like 300w to the sub.

pet575 · Posted: Jul 01, 2011 8:42 am Post subject:

holdsworth, did you try swapping the speaker leads and the outputs? What I mean is, did you try putting the tower speakers on the 2 bridged channels (and unbridge them) and put the sub on the channels currently running the tower speakers (and bridge them)? And of course switching the filters from low-high and high-low?

If you notice you get crappy performance out of the tower but good out of the sub-you'll know it is an issue with the amp. If it acts exactly the same then you'll know it is just a crappy amp for what you're trying to do with it.

loudsubz · Criminal Joined: 10 Aug 2008 Posts: 77 City: Mississauga

was there an older sub running off the amp before or is this sub new with the changeover of the interior speakers? Just wondering if you had any comparisons to before?

holdsworth · Posted: Jul 05, 2011 2:58 pm Post subject:

pet575, yeah, switched everything around, same result.

loudsubz, 12" Kicker was connected to same amp before, was the same thing going on.

loudsubz · Criminal Joined: 10 Aug 2008 Posts: 77 City: Mississauga

try taking an ipod to and use some 3.5mm to RCA jacks and plug it into the amp and see if you get more volume out of it.

You can also use a volt meter to measure the AC output from the speaker terminals when running a 50 hz sine wave through it. You should be able to measure what wattage you have coming out of the amp by using the nominal resistance of the sub and voltage you measure than plug into this

http://www.sengpielaudio.com/calculator-ohm.htm

It won't be 100% because of the way impedance plays a role but will be good ebnough to give you an idea if your amp is toast.