ok I have a kenwood head unit KDC-BT645U that I have a set of fosgate tweeters and mids at head level in my 66 truck, and 4 polk 6x9s run off the rear of the unit in parallel. the sound is great but I need a little more oompf bass wise from the 6x9s. I have a kenwood m450 mono amp that I can run to them but seeing as how they are a full range speaker I am afraid that I wont be getting full advantage of there range. so do I need to buy a 2 channel amp? and if so which do you recomend with those speakers specs or do you think that my quest will be all in vain seeing as how they are just 6x9s. I have absolutely no room for a sub unless i relocate the gas tank which isnt an option at this point. as i said I just wanna punch the bass to the 6x9s a bit more. any info will be greatly appreciated, thanks Shane

 

Running those 6x9 off an amp will give you more power and possibly better output. But to geometry of a 6x9, 3 way driver out of the equation, you'll need get great bass response out of a 6x9. Will you get more than what you have now after amping? Probably so.

I'd buy a 2 channel amp if you want to try it. But ultimately I'd use that mono amp and a single 8 to get more bass. 8s are small and depending on your listening style will produce more then enough.

 

Or another option but I don't know how it will work. Run 2 6x9s off the HU and run the mono amp on just 2 of the 6x9s and run the filters on the amp and only push bass. I don't think it will work great and IMO you'll probably trash the 6x9s but you wont have to buy anything and you can try it out.

 

They make 6x9 subs (midbasses really, but still decent). But more important is how are these things installed? What vehicle, what locations, with or without enclosures, etc...

You should be able to get some respectable bass by reworking your current equipment but I need some details first - you've totally hamstrung yourself with the current configuration. Pics would be good of 6x9 mounting too.

 

how do you mean hamstrung? first off I take no offense to that so dont read my response that way but what have I done to hamtrung myself. I am totally open to input here. its a 66 truck so I have absolutely no room in the cab. I just needed some sound in my truck so I thru together what I had. its a kenwood HU KDC-BT645U. then I have two speakers ran in parrallel to the front channels on both sides (a pair of fosgate tweeters with bass blockers on them and a pair of Polk Audio DXi525) these are at ear level mounted in the upper rear corners of my cab. so I can hear plenty of highs and higher mids from those. on the rear channels I have a pair of Polk Audio DXi690s on each of the rear channels. they are mounted without enclosures on a very well mounted 1" thick board going across the cab under the rear window at a 45 degree angle. as I have stated I have absolutely no room in this truck. the gas tank is mounted behind the seat so I have no room for an enclosure there and only have 5" space under the seat. I know I will never get anywhere near a super quality sound out of this truck without major reconstruction but I would like to get a lil more bass.


Speaker Set up Pic

 

Hm, good picture & explanation. So you've actually got a decent equip setup here, just a bad implementation. With some re-working this could sound pretty good. Cool looking truck too.

Hamstrung, meaning not optimized, didn't mean to sound cynical

A couple more questions - under the rear decking, what's behind the foam? Gas tank? Any empty space there?

Polk 525's - are these in an enclosure or sealed at all?

The Fosgate's (those are 2-way mids right, 3"?) - again, any enclosure behind it?

I already see the wood deck is open on the side, I suspect the same is going on with the others too: back wave cancellation. What's happening with any speaker w/o an enclosure is the back wave is coming around to the front & cancelling out the lower frequencies.

Your other prob is the wiring scheme, in series you're getting about 4 watts per driver.

Here's what I'd do, assuming this is the case. First, pull the 5.25's & mount in lower doors. It takes some modding but with a spacer & a 4" hole it's not tough. If I couldn't do that I'd pull them out completely. The LAST thing you want is a speaker right by your ear for about 20 reasons. 21 if you have a plate in your head. Mounted in the doors they'll sound a world better.

The fosgate mids are gone, they ain't doing you any favors. IF they'll mount in the dash that's not a bad option tho. But more speakers doesn't make it sound better usually. If anything it muddys it up.

Next up are the rear 6x9's - pull that wood deck off the truck & fabricate simple wooden enclosures around them, something to seal the back waves off, then reinstall - if you can turn that deck into 1 long box, perfect.

If that isn't possible you can get pretty close using just that acoustic foam & some spray adhesive, just seal it as best possible - the more sealing the better the bass. This is total ghetto but whatever works.

Run the front 5.25's on the headunit's front channel. Run the two outer 6x9's on the rear channel. Run the two INNER 6x9's on the sub amp, it should fit under the seat no problem. Crossover frequency isn't critical here, I'm thinking 120 hz is good - use the x-over in the headunit, not the amp, and be sure the mains are set for high-pass. If there's a subsonic filter on the amp set it at 40 hz. This is unlikely tho, just guessing. Wire the "subs" in series to keep the power down from that amp, or wire parallel & set gains VERY low.

Just my .02, good luck.

 

Ok soungds great! thanks for the input. slight error in my description, not that it matters tho is that I have my speakers wired in series not parralel. sorry. but ya this weekend I will get rid of the fosgate tweeters, run outer 6x9s to HU and inner 6x9s to amp. underneath the foam is the gas tank and theres not even enough room to put a 1/4" board inbetween the magnets and the tanks. I have rubber strips glued to the backs to keep them tight and from rattling. I will probably just surround the backs with more foam. same with the 5.25"s none of them are enclosed. I installed the foam because the whole cab was reverberating so had to quiet it down some how hahaha. I am not opposed to ghetto. my whole truck is a lil ghetto haha. thanks for the info again and I will let you know how it turns out.

 

Ghetto it is then

Beware that the results won't be nearly as good trying to seal with foam but it could work. I assumed it was closed-cell foam, if it's open cell I don't know if it'll help. If you can breathe thru it it's open-cell.

Plan B, since it looks like you're handy with woodwork - rotate that wood deck forward & build the box around it, maybe raising it a bit. Use all 4 6x9's (wired series-parallel) as subs firing into the back of the seat. Then rely on the door speakers as mains. Really that's a great fiberglass project but might be too technical for you. I don't even like messing with that stuff. But you'd have great bass.

Have fun this weekend with it.

 

Ya i hate fiberglass, plus if and when i want to get that deep into it i will most likely end up relocating the gas tank and making a custom box for it since i would have room. The way it is sandwiched in there now its a good thing im short cause the seat is all the way forward and cant go back at all with the speakers as they are. Im not joking when i say ive optomized the space as much as physically possible.

 

OK sorry it took so long to repost findings. just got to it tonight. moded a jerry rigged sheild on my board behind the seat and put a kenwood 2 channel amp on the 4 6x9s parallel wired which will lower them to 2 ohms and each will handle 100 rms so with the amp putting out •60 watts RMS x 2 at 4 ohms (75 watts x 2 at 2 ohms) i figure there getting 32.5 watts each and then wired the front leg in a parralel also which there only getting the higher frequencies and ive adjusted the fade so there less prominent. either way it sounds great now. again i am a novice audiophile but not a professional by any means and it sounds pretty damn good for a 66 cab and a bunch of ghetto riggin haha. any input on what i have posted if i am wrong about any wattage or anything is appreciated. i dont think i am gonna burn anything up but someone might inform me different. thanks again for all your help, without it i wouldnt have been able to drown out all the road noise lol

 

Cool, glad it worked out. Your math looks right, I think your speakers are very safe with those numbers.

Two ideas for you - first, try fading out the fronts (assuming you didn't door-mount them, no?) & see if it sounds better with just the rear speakers. Second, if the rear deck only got a shield rather than an enclosure you could try stuffing a bunch of poly fill in there to further insulate that back wave. poly fill is basically pillow stuffing avail at any wal mart's fabric section, about $5.

I noticed I kicked the terms in my earlier post, you think I'd get them straight after all these years but I still confuse parallel with serial. Corrected.

Have fun!