View Full Version : Woofers bottoming out...why?

05-31-2005, 11:17 PM
Hey guys,

A couple months back, I thought about throwing my rear fill onto the HU amp and just bridging my ARC KAR 400.4 to power my Rainbow SLC 265 front comps (using the passive crossover they came with). The speakers are listed at 100 watts rms and the amp at 200x2 at 4ohm bridged. When I tried hooking the speakers up this way, with the gain on the amp up less than half way and the volume a little better than half on the HU, my woofers were bottoming out a bit. Only thing I can think of is reversed polarity, since they should be able to handle the power I was giving them. IIRC, the positive and negative terminals are not marked on the rainbows. It's just fat and thin connectors. Maybe I guessed wrong when I hooked them up. Anybody know for a fact which terminal (fat or thin) is positive and which is negative?

Would my speakers be bottoming out for any other reason? I think I had the bass boost up about half-way (maybe a little less), which should be around 9dB. Those Rainbows don't seem to put out adequate midbass. Maybe it's just me. :confused:

06-01-2005, 12:22 AM
Reversing the polarity would have nothing to do with the speakers bottoming out.

The bass boost, however, would. Turn that **** off.

Also, be sure you have your gain properly set (sounds like you do not).

But yes, it sounds like you are simply overdriving the speakers. Reset the gain lower if needed (sounds like it needs to be), turn the bass boost off, turn down any other EQ bands that you may have boosted. And if you still need more midbass, read through the sound deadening tutorial and such about how to properly install the mids to maximum performance. Sounds like a setup issue, not lack of performance issues.

06-01-2005, 12:44 AM
I can't add anything of real value outside of what Squeak has already posted but just so you'll know for future reference....unless Rainbow does it backwards from every other brand of speaker I've ever had my hands on when you've got wire input terminals of different widths it'll be the wider (fatter) of the two that's ("+") positive.

Good luck getting it sorted out!

06-01-2005, 12:59 AM
Im not sure about the rainbows, I will in 2 days. But my IDcxs64s bottom out with the bass set at flat. I didnt change anything just the mids to some OZ-180 and they didnt bottom out. Im sure that with my doors not deadened at all that might have something to do with it, also seems some mids will bottom while others will distort rather then bottom.

06-01-2005, 01:06 AM
turn your boosts down, make sure its all installed PROPERLY, and most importantly,


thats what squeak said in a nutshell. because obviously, there is somthing wrong, and i can almost be 100% sure its not the equipment.

06-01-2005, 01:22 AM
Thanks guys. I was afraid it might be the bass boost. I guess I'll turn it off, even though I really like the added bass.

I have like 20 sq. ft. of E-Dead V1se that I bought a few months back and have been waiting to install. I know it won't cover both front doors entirely, but I'll do as much as I can, and I'll definitely do the area behind the woofer.

Thanks again for the help.

06-01-2005, 01:47 AM
just get a bottomless driver

06-01-2005, 01:16 PM
It's definitely not a fault in the rainbows. I've pushed mine pretty hard with a 40hz highpass, but never bottomed them out. It's sad to hear what someone put those poor speakers through. :cries:

06-01-2005, 07:35 PM
you should not be using bass boost for fronstage speakers- thats a crime.....as is not sound deadning those doors

06-01-2005, 08:55 PM
you should not be using bass boost for fronstage speakers- thats a crime.....as is not sound deadning those doors

i agree! they should give jail time for things like this lol.

Deadener will help improve your midbass but the bottoming out part sounds like you are exceeding there mechanical limits. This can be cause by to much power, to low of high pass point or when installing u could have bent the frames. Ive had this happen a couple of times when using stamped framed drivers. I didnt realize the mid wasnt laying flat and just screwed it down lol.

06-01-2005, 09:21 PM
Thanks guys. I was afraid it might be the bass boost. I guess I'll turn it off, even though I really like the added bass.

Not to be a smart *** or anything remotely close to that but if you like alot of bass why not get it from your subs?? :(

You do have subs right??

One more thing......in my15 yrs of car audio I have NEVER used a "bass boost" or anythng else like that. A bass boost is nothing more than a band aid for a bad install. If a sub is not putting out enough bass to begin with then it is plainly not the right sub for you and using the boost is only putting unwanted strain on your amp.

06-03-2005, 07:31 PM
Why do they even put bass boost on the amps...just 'cause they can?



06-03-2005, 08:49 PM
it's like chrome on an amp. Not necessary, but some people like it as a 'feature'.

06-03-2005, 09:14 PM
actually you CAN use it, but youll have to turn the gains down. so yea its useless. hehe

slick rick
06-04-2005, 03:14 AM
Brian where was the post on the org about this?? NO BASS BOOST at all,ever. :) you should never need it with a proper install. also 20sq is fine for 2 doors to sound deaden.

06-04-2005, 09:03 AM
I didnt read all of the posts but if you are bottoming out that means that you are over excurting the speaker. Try raising the crossover freq.

06-05-2005, 11:08 PM
Well, turns out I had the polarity reversed. I haven't listened much yet, but from a few songs, the bass seems to sound better.

I turned off the bass boost on both amps and amp now running clean.

Thanks again guys.