interesting idea, perhaps

hellohello · October 2003

Ok, it all started a few years ago, i bought 2 ex 10's to use in my car, but never did, and in the closet they went.

Years went by and i became a bass player (how convenient).
I have a five string (low B)and my current amp doesnt seem to cut it. So... in my quest to upgrade my musical instrument amplification (dont that sound smart lol) i realized that cabinets were going to be expensive. I recently rediscovered my polk ex 10's and had the devilish idea to build my own cab. the polk's are not made of paper, like most of the ones ive seen in premade (manufactured) cabs, so they should last longer, sound better(i assume). I just wonder:

1. is this idea even plausible
2. what dimensions i should use, the manual says 1 ft^3 sealed or 1.25 ported, but those measurements are for a car, not exactly what im doing.

Well, thought i would share my idea to save dough, and put some use to some unused speakers

MTXMAN · October 2003

downside is that most bass amplifiers are running an 8ohm signal and that's about all their rated for (fellow bass player here, 4string Ibanez and a 75w 15" Peavey amp) if you ran the subs to 8ohms they might be alright but then you're running them in an area where car audio wasn't ment to go... Also the speakers you'd find in a cabnet are designed to play fullrange to get the harmonics etc. however caraudio subs are designed with the fact that they probably wont be played over 200hz. I'd be hesitant to do it myself but some of the other guys can offer a better researched opionion

PoweredByDodge · October 2003

i agree completely, those EX 10 subs might (if you really pinch the indian till he jumps on the buffalo's back) squeak up to like 200 hertz... 250 hertz... they're not meant to play any higher, they're subwoofers, not woofers.

However, if you can find a good set of NON PAPER (since i hate paper **** speakers, my next set of home stuff is gonna be bulletproof if i ever get some money) woofers that'll play "full range" enough to cover the spectrum of the bass guitar, cross them over at like 125 hertz high pass, and then run the EX subs at 125 low pass, all off the same amp, and then you've got a cabinet!!!

you'll just need an assload of power... 150 watts per speaker i would suggest.

if they're 4 ohm subs, then something that's 300 x 1 at 8 ohms... if they're 8 ohm subs --- 300 x 1 at 4 ohms...

you can actually then go and get the two full range woofers (find something that's 150 rms each so that you can wire it as i'm gonna say) and get the same impedance woofers as you've got subs (if you've got 8 ohm subs - get 8 ohm woofs / 4 ohm subs, get 4 ohm woofs) ... wire the woofs the same way u wire the subs... so jump the 4 ohm woofers in series up to 8 ohms, just like you've got the subs in series to 8... then just parallel the woofers and the subs together... think you're gonna get a 4 ohm load right? wrong -- by using a high pass at 125 on the woof and a low pass at 100-125 on the subs, you'll end up splitting the frequency spectrum, and the amp will see all 4 speakers as a single 8 ohm load.

... now just have fun trying to find a 300 x 1 at 8 ohm mono (or bridged) amp.

hellohello · October 2003

Originally posted by PoweredByDodge
wire the woofs the same way u wire the subs... so jump the 4 ohm woofers in series up to 8 ohms, just like you've got the subs in series to 8... then just parallel the woofers and the subs together... think you're gonna get a 4 ohm load right? wrong -- by using a high pass at 125 on the woof and a low pass at 100-125 on the subs, you'll end up splitting the frequency spectrum, and the amp will see all 4 speakers as a single 8 ohm load.

... now just have fun trying to find a 300 x 1 at 8 ohm mono (or bridged) amp.

ok, i i understand the series wiring part, its just the crossover part that throws me. I assume you speak of using passive crossovers, and if thats the case, do I parallel the inputs of the two crossovers?
And what would be a good brand to use, and what do they run?
im trying to go cheap here

i found an amp that runs 300 watts into 2 8 ohm cabs or one 4 ohm, could i just seperate the subs and woofers into two sections?
http://www.behringer.com/02_products/prodindex.cfm?id=BX3000T&lang=eng

PoweredByDodge · October 2003

for this application i'd suggest building your own crossovers... and assuming you get parts are a halfway decent price you could be "out the door" for like under 30 bucks.

magic mike · October 2003

i'm interested in building my own crossovers, i dont have much info or kowledge on this subject, anybody have any infofor this, ie web pages ?

PoweredByDodge · October 2003

idea 1 ---

www.the12volt.com

idea 2 ---

take electronics tech at your local tech school

idea 3 ---

www.the12volt.com

hellohello · December 2003

ok, im a hesitant **** i admit it, but i just want to get everything clear including my calendar before i get started and with school ending for a month and my recently getting fired, that all works out.

now im revisiting my old plans to keep me occupied over the break and i still have a few questions (suprise suprise)
which crossover would be best, i looked at the 12 volt.com and it lists a 6db 12db and 18db i understand that the 6 db would allow more higher frequencies through and the 18db would cut off the steepest, but with my limited experience, i have no idea which of the three would work best for this application
oh, and about those 10'woofers 150rms that pbd recommended for the high pass, i had to match the polks which are 4 ohm and all i seem to find that fit those values and are not made of paper are car audio subwoofers and there are some that go up to 2500hz, would they work?
thanks for looking and in case ur wondering, the job wasnt too great anyway

PoweredByDodge · December 2003

dude, run 6x9's -- get a 90 dollar pair of 6x9's (like polk EXIII's, new dB's or even find some used polk DX's), and use those as the "high passed woofers" -- cuz they'll play down to 40 hertz, but shine around 100 and up.

as far as crossovers... i'm partial to 12 db / octave xovers, and they're not too hard to build. 6's will work and be the easiest and they wont cause any problems... just be smart about which freq's u choose to crossover at.

if you want to make sure you dont get any "real high" notes, then snip the wire going to the tweeter on the 6x9's, that'll give u the woofer and mdirange parts working with the tweeter muted.

hellohello · February 2004

well, she aint pretty, but after a good week shes done and doesnt sound too bad, considering it only cost about 150 all together. i wired up the inputs on the cab so that it can be switched between all four speakers at once or 2 per channel, but i dont think it worked out the way i thought it would. i went with the behringer amp which puts out 300 watts for 2 8 ohm cabs, but it doesnt make a huge difference whether its in all four or 2 per channel mode. will it read the 2 per channel as a single load even tho the two are on different outputs from the amp? if so, could anyone direct me to a 300 watt 8 ohm amp, or maybe a 600 watt 4 ohm car amp....

interesting idea, perhaps

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