bryons2000

Could someone help me out here? I have a custom fiberglass molded box with 2 JL 10" subs installed in the trunk well. I am using a cheaper amp, but it seems to work fine...It is a Koiler (?) amp, that supposedly kicks out 400w RMS (bridged).

The bass seems alright with the top up (less the vibrations), but when the top is down, I might as well turn off the amp. I can have the stereo cranked up with the top down at 50 mph, and only hear my door speakers and lucid rear panels. Does anyone have a solution here? I was thinking of some way to port the trunk panel and run a tube of some sort to my panels behind the seat to fill the cabin with bass...would this work? What have some of you all done to get the bass from the trunk?

Another note~ If I pop the trunk in the garage with the music up it sounds like I am in a club...so I know that the speakers are at least being pushed.

Thanks in advance!!!
Bryon

lucid

400 Rms is on the low side to begin with and cheaper amps tend to exaggerate their claims (who's gonna check?) The other thing it could be is the wiring. What load are you running? Are they wired series or parallel?

Crutchfield (cough) has a Clarion DPX1000.2 amp that may be decent choice (cheap too). Clarion has been good in the past, specs are nice BUT the power/ground terminals aren't.

lehighwiz

trust me...if you push enough to the subs, you will hear it at any speed. I have 1 ten inch kicker sub mounted in a custom enclosure and it pounds. I have it driven by a rockford amp brodged to 1 channel...i forget the specs on my amp as it is a few years old, but it is a good amp. is your box ported? i know that JL subs need alot of RMS power to really pound. If you are not already running the subs in parallel, i would try that...

matt

bryons2000

Thanks for the input.

I am not sure what the difference is between series and parallel...I do have both subs running to the same terminal of the sub box, and the one wire pair comes out of the box and runs to the amp where it is bridged...is this series? I am definitely going to get a better amp soon, but if I pop the trunk with the stereo cranked, the speakers really seem to be pushed. So is it common to not do a custom porting job to get the bass from the trunk to the cabin?

The box, which was purchased from a board member here, came ported. Should I have these ports sealed up?

Stratocaster

One thing to note about amps, There is NO standard for RMS to be measured. Vendors get to do it how ever they want. Have you ever wondered why a 20" TV is the same size as a 19" computer monitor. TV's get spec'ed one way by Law, and Computer monitors another. Car amps, Home amp it is a crap shot on how it was done.

Just something I learned when I sold and repaired them.

bryons2000

Also, how high should I place the power level and bass level on the amp? There is also a "bass boost" switch...do higher quality amps usually have these, and do people usually use them?

lehighwiz

when you open the trunk you completely change the pressure surrounding the subs. the trunk itself forms an enclosure of sorts...when you open the trunk you will notice a difference in the sound that the speakers produce. I like to keep the gain and any other settings in the middle on the actual amp, and do any fine tuning on an EQ or with the head unit if capable. if you run the amp positive to both positive terminals on both subs and likewise with the ground, this is parallel...if you daisy chain the subs...that would be series...however it sounds like you have the subs already in parallel. ported is fine, but it requires more power to really push the subs to their true potential....are the JL subs that you have dual voice coil? if you you really might be overloading you amp with the subs in parallel.

Matt

lucid

parallel lowers your impedence, series raises it. If your 2 subs are connected to a bridged amp positive on both subs to positive on amp and negative on both subs to negative on amp you're running parallel thus lowering your impedence and making your amp work harder. 2 subs of 4 ohms would give you a 2-ohm load.

If its in series, it would be positive from amp to positive on 1 sub then the negative on sub 1 to the positive on sub 2 and negative on sub 2 connecting to the amp negative. If both subs were 4 ohms it would raise give you a 8 ohm load.

Other considerations are the gains/input sensitivity on the amp itself are they too low?

Don't seal up a good ported box! Most likely you have a power issue somewhere.

lehighwiz

if they are JL 10W6 subs i think they are dual voice coil...if you have everything in parallel...you would be pushing .75 ohms...which is out of the operating range for some amps.

lucid

Oh yeah, DVC that would make things more interesting. But if he had a load of .75 ohm for a little while I'm sure the amp would fail.

Only amps I know of that can handle that are tres expensive. I'd bet they're just SVC.