need help with wiring tweeters

[Basscrime]

Hi, we have a bunch of subs the we run at our partys that we usually just put some 15's ontop of. we want people to be able to stand right infront of our subs without hurting there ears. so we are going to be building some selfpowered speaker cabinets, we were thinking 4 dome tweeters in each cabinet for highs with a 12 in the center for mids and midlows giving us some mains that we could put ontop of our subs that would sound nice for people to listen to at close range without hurting their ears.

My problem is that need to figure out how to turn 4 8ohm dome tweeters into a 4 ohm load on a single amplifier channel, the only I could think of wiring 4 tweeters into a 4 ohm load would be to use 4 ohm tweeters.
wire 2 four ohm tweeters in series to make and 8 ohm load, have 2 sets of those and turn it back into a four ohm load by wiring the 2 sets of speakers in parallel.

example here.



I would be doing this on a powersoft digimod 500 for the 4 tweeters.

[qusp]

is using a bridged amp out of the question, bringing the impedance 'seen' by the amp down to 4ohms by using the same example as your 4 x 4ohm series/parallel circuit above?

[Inductor]

Look at AR-LST for ideas if using multiple tweeters. You can go with a pro (4/8 Ohm) dome instead (4 "home" drivers). Look at the SPL. The configuration of the tweeters per si (impedance is fine) is not going to give you a good sound. There are also some nice PA cone tweeters with nice specs that would mate nice with a 12" driver, the problem is that's difficult to go with a horn(s) at those low frequencies and the option is (like you) the use of a low crossover frequency and drivers. The dispersion needs also some care.

[Basscrime]

why wont wiring that many tweeters up to one channel sound good, is there mud being created when running a series/paralell configuration?
the reason we want to go with 100 watt silk dome tweeters is because horns hurt peoples ears, we want people to be able to enjoy standing infront of our subs and not have ringing ears by the time the partys over, our solution is to stack mass silk dome tweeters, they sound crisp, clear and arent as abrasive on the ears as high powered compression drivers.

why exactly would this setup not sound good??

[Inductor]

Originally Posted by Basscrime

...why exactly would this setup not sound good??

Is not why. All designs when they are well setup can sound good. You don't mention SPL. (The problems with multiple drivers, good for dispersion as you see in home/cinema/theaters/surround, is the anti-phase and nulls you will get if you don't know or measure.)

[Basscrime]

We are going to have horns, placed at different angles to fill in other gaps, Ive never heard of this "anti phaze and null" that your talking about, I would like to know more.

[Inductor]

Originally Posted by Basscrime

We are going to have horns, placed at different angles to fill in other gaps, Ive never heard of this "anti phaze and null" that your talking about, I would like to know more.

I don't have an idea of your set-up, sorry. You mention domes and horns in this same thread. I only mentioned with no feedback from you, the case of the AR-LST. You can look at the problems of nulls at high frequencies. In your case is multiple tweeters you are designing.
Here a good paper from Wayne Parham. I think JBL also has some info (besides the forums and links).
Pi Speaker Forum - Baffle spacing, phase angles and time alignment, revisited - Wayne Parham, May 14, 2003 at 00:56:30

[Basscrime]

Sorry, I should have told you my whole setup before i started getting into this.
were have a bunch of single 18" subs all lined up beside eachother infront of the stage.
We have a pair of samson db500a's for mains right now, once we have built these cabs well put them farther out to the sides and point them inwards at an angle towards the dancefloor.

Read the article you sent, great info. I also looked up the AR-LST speakers and love the design idea, I might end up designing them just like that.

I wasnt able to find 4 ohm tweeters so this setup wouldnt exactly would out that well, the only thing i could think of would be to run all 8 ohm tweets and in order to loose 4 ohms i would add another set of tweeters in paralell ontop of that, on paper that should be a 4 ohm load but would that be risky for an amp?
I will be using class D amps, dont know from which brand yet but the more I notice about class D amps is that they all put out there highest output at 4 ohms. I would like to have 6 domes per cab like the AR-LST's and this was the only configuration that i could possibly get 6 8 ohm tweeters to run at a 4 ohm load off 1 amp.

I havent bought any parts for this project yet, were just starting to design these speakers and want to source out all our options possible and make them the best that they can be!

[18Hurts]

I understand what you want....

You want fill speakers so if people want to stand in front of the subs (they like the pressure waves) the highs won't blow their hearing.

Put the main PA speakers for the rest of the world away from the subs and put small fill speakers on top of the subs and set the gains low enough not to be very loud when standing right in front of them. Normally, I would have the horns aimed over the crowd to minimize (drunk) dancers from getting ear burn as they go by.

Have a set of 6 foot tall vertical line arrays in my garage--complete with 48 dome tweeters each. Traditional math when it comes to the short wavelengths with tweeters does not work like subwoofers do. If it did, my 48 dome tweeters running 90dB each should give me around 107dB at one watt--that does not happen. Can't expect a 2.5 inch wavelength to couple to a tweeter 6 feet down the line. Instead of 108dB, I get 96 to 97 dB when running them at 4.5 ohms--the mids run at 13 ohms so I can push the tweeters harder to get them loud enough. My tweeter line can be 20 feet tall and run 160 tweeters and it won't get any louder...

One thing a vertical line array does do is as people get really close to them, more speakers go off-axis so that limits SPL from the highs--it gets really mid-bass heavy but won't smoke your ears. They will sound weird but won't start your ear hair on fire. (when I play them at 10 to 20 watts in a garage).
Vertical line arrays--now drunks will stand even CLOSER to your speakers!

Generally speaking, you don't want people standing in front of your speakers for many reasons, such as spilling their drinks, vomit, cigarette burns, they might try to climb on them etc. Horn burn will usually keep people away so low level fill for mids/highs while running full bore subs, is like an invitation for idiots to stand in front of the PA stacks to screw up your sound.

[Inductor]

The problem is still on. The advice given mentions a lot of experience. Are your speakers only for PA (not accurate as I understand).
In building the AR's you mention

I would like to have 6 domes per cab like the AR-LST's and this was the only configuration that i could possibly get 6 8 ohm tweeters to run at a 4 ohm load off 1 amp.

I think they have (4 + 4) 8 domes and a 12" each. So if you have 4 drivers (mids and tweeters domes) you can get back to it's original impedance 8x4=8 or 4x4=4. Also what is the crossover region you are going to use, that will give you a good transition between 12" woofer and the tweeters using the mid domes as in the AR's.
Beyma has professional drivers for PA (for many years), also good domes from CIARE look at MT320.

Basscrime,
Resuming, I think the problems you mention in sound is more of a poor design balance and inaccurate reproduction together with defective (distortion) amps and speakers all in dispersion, SPL and crossovers, and you will end just repeating what you mention with your approach, a poor designed system, maybe with no balanced mid level and highs with peaks and dips, unless you are careful. You have an active or passive system? If you don't want to build a loudspeaker, I think would be nicer for you if you move to the PA forum instead or give it a look.
PA Systems - diyAudio
http://profesional.beyma.com/pdf/12BR70E.pdf
http://profesional.beyma.com/ingles/pdf/MC115.pdf
http://profesional.beyma.com/ingles/pdf/T2010.pdf
http://profesional.beyma.com/ingles/pdf/T2030.pdf
99db dome tweeter without titan and without horn ?
Zaph|Audio