Ideas for a cheap party speaker

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in my quest for a lo fi, inexpensive, loud party speaker (think cerwin vega, bump and sizzle sound) ive come across two drivers, which i think could work well together.
each speaker will have:

4 10" woofers
http://www.partsexpress.com/pe/showdetl.cfm?&DID=7&Partnumber=290-274
and two piezo tweeters
http://www.partsexpress.com/pe/showdetl.cfm?&DID=7&Partnumber=280-062


im not really that much concerned with SQ it should have bass and be able to play loud and be somewhat durable

for the enclosure i modelled 4.0 cuft tuned to 40 hz wia two 4" ports looked good

my only concern is, do you thin the pyramids can really reach 1800hz? (the natural crossover point of the piezo tweeter)

crossover wise i was thinking to let the electrical properties of the piezo tweeter run their natural course and roll off the tweets at 1800hz, and then have a second oder croossover on the 4 woofers at 1800hz. cheap and simple.
 
seen it, not really interested, doesnt have close to as much low end, and wont be as efficient or loud.

really the only thing im asking is if the pyramids can make it up to 1800khz to cross to the piezo. it doesnt need to be too smooth, and if its like 1db down at 1800hz i dont care. the frequency response spec at partsexpress say that it can go up to 3khz, but i dont knwo hwo accurate those kinds of specs are.
 
Stephan,

It will be fine. I wouldn't be too concerned about your FR graph or SQ, these are party speakers. You're wanting to use four woofers instead of one larger one, you're wanting to use two horn tweeters in the same cabinet, piezos to boot. What are you expecting?

I don't know if you need the 12dB XO on the woofs. I'd be tempted to run only a coil on the woofs and a cap on the piezo to hopefully reduce that annoying piezo sound.

They will be fine for what you are doing with them. I used to build a dual 12" and piezo for my party friends and they all loved them. It was a horrible combination of high Q woofers (read small magnet) and again, that oh so wonderful piezo in a plywood box. I ran them MTM (before there was a name for it) and took insulation from my parents attic. No grille, no finish, just raw speaker fun.

Ah, those were the days.
When volume used to rule.
 
those are the kind of speakers im thinking, and apart from mids coming out everywhere i dont see whats wrong with 4 10s, as far as bass goes its gonna rule (if you model it its got a big 4db bass peak, but useable extension down to 40hz in only a 4cu ft box tuned to 40 via two 4" ports).

but will they have REALLY scooped mids? thats really what im worried about, i wanna have a bit of a loudness cruve going on.

about piezo tweeters, putting a first order high pass on it with a cap requires you to do some weird resistor combo thing with the piezo. but from the piezo article at partsexpress i go the idea that i could just do a crossover for the woofers, and paralell the piezos with the woofers before the crossover and that would gimme a corssover point on the piezos of 1800hz. i also got the idea that that would give the speaker a nominal impedance of the 4 woofers in series paralell(4 ohms).

if my thinking in the previous paragraph is right i just might do that and see if im satisfyed, if not ill make some more crossover mods.
 
I think one question here is about the woofer behavior in the 2 to 3 KHz area. 10" woofers become directional at this point. If you put your ears right on axis with the woofer, you will hear it. But if you move away from that, these frequencies go down in amplitude somewhat.

In addition, curves that I have seen for these tweeters show declining output below 2.5 or 3 KHz. You could start your project by not using a cross-over at all and it might sound good enough as is! Then you can try experimenting with a crossover to improve it.
 
im not too worried about directionality cause ive heard PA speakers with 12s(or gasp even an 18" two way system once! but that sounded kinda wrong to me although no one else seemed to care :rolleyes: guess you get an idea of what kind of audience these speakers are gonna be getting!) crossed to piezo or bullet tweeters, and that was kind of the sound i wanted, bump and sizzle, somewhat scooped out mids. a slightly more aggresive treble isnt bad either.

so im guessing that using a ten would have even better off axis.

so far the design looks like a go ahead, so i should just build it, and if i feel like tweaking it then ill come back here, and if its good enough ill let it be?

apparantly the whole amplifiers blowing up, is only the case with class d and the likes that have significant output really high up. this will get runn off this tough as hell old cheapie home reciever(ive ran a 2 ohm load off it for months and it was fine!). so can i just paralell the piezos with the woofers before the crossover? also what final nominal impedance would that give me(4 would be nice but 8 would work too)
 
anatech said:
Hey Cal,
I don't have any mosquito repellers. Want to share?

-Chris

Chris,

It boosts the high end from about 6 or 7k up to equal the 2-4k screech that piezos are so good at. It actually makes it a more pleseant sounding mosquito repellant. Doesn't get rid of the screech, it overcomes it with a boost in the high end.

Now you know why I really had no reason to try this but am very glad I did. It's the only time I can listen to a piezo and not know what kind of tweeter it is.
 
ok cal that sounds like something id want to o, i mean if its only a coil in series...and nothing else and it makes a big dif like that ill prolly end up doing it. so a coil in series with the woofers and another coil in series with the tweeters, and then wire them paralell...so now i got a question.

i wire the piezos in paralell right? i need that extra 3db efficiency to keep up with the midwoofers.

and whats the final ohm load if i do this?
 
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Cal,
That sounds like a damped resonance to me. It would be interesting to measure the Q of that system (piezo choke). It is a series LC with more damping than I thought there might be.

Betcha the inductance makes the amplifier a whole lot happier too!

Xstephanx,
You have to think of a piezo as a capacitor. The impedance falls as the frequency goes up. The spec sheet should tell you this.

-Chris
 
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