Hi, Im not to happy with the sound from my speakers, There using 15" emminence speakers which im happy with but I feel the piezo horns that were fitted from new may be letting them down, Im contemplating fitting compression drivers and crossovers but I really dont know too much about them, does anyone have any advice? I dont want to buy new speakers yet as I simply cant afford them just now.

You will certainly get a better sound, piezo horns are horrible but honestly i'm not really sure it's a great idea.

Without trying to be offensive, if your cabs had piezos fitted then they are most likely a very cheap budget brand. That usually means that the actual cabinet and probably the bass driver aren't worth spending the extra money on.

I'm guessing here that to buy the crossovers and drivers you are going to be spending at the very least a hundred quid. I know you said you aren't looking to buy new speakers but for the same price as fitting new drivers you could pick up a pair of much better quality second hand speakers that would sound far sweeter than your modified cabs.

Just an example, I recently bought a second hand 4 speaker NJD system (12" tops + 15" bins) for £150 as backup and they sound great!

Have to agree with fester on that one. a set of compression drivers and crossovers will cost you a few quid and it will be dead money. Cabs that have been modified have a lower sh value. You could pick up a set of peavey hisys 2's for less than £150. they have a set of 15" black widow main drivers and a quality voice coil. I use them all the time and even do school proms in big halls up to 200 people with no problem.

big heavy robust and as many would agree, they were high quality speakers in their time.

regards
Dave

What sort of piezo tweeters are fitted at the mo? Can you show us a pic? Are they bullet tweeters, piezo drivers screwed to a flare, or a piezo flared-horn single assembly? If they have seperate horn flares, maybe you can find a compatible screw-on driver that will save you a bit of money.

Eminence do some quite cheap compression drivers, and you can pick up cheap crossover boards on the net if necessary.

The size and shape of the tweeter (eg bullet or horn) will very much determine how the speakers sound at different points in the room, what sort of 'throw' they have and their dispersion angle.

It will certainly give you better results than a piezo, but be prepared to modify the crossovers since they may not suit the voicing of the cabinets straight out of the packet. For example, you may find the treble becomes overpowering (ear bleeding!) in which case you'll need to fit an attenuator or pad to the crossover board to tone them down a bit. Ok; you could take it up by EQ'ing the mixer but you'd be better getting the speaker about right on a flat system first.

If you see some horns that fit the cabinet without too much mangling and jigsawing, look at the datasheet and then you'll have to decide what crossover frequency you need...they come in all sizes.

A rough, wing-it guide is to look at a commercially available disco speaker with compression drivers as standard, find one with cabinet dimensions and woofer as close to yours as you can, then try and find a data sheet on that particular cabinet to see what it's crossed-over at.

Get a tweeter thats designed for disco or pro use, steer clear of domestic ones no matter how high-power they seem.


Eminence example

They are screw on 1.3/8 thread piezo and I think there 10cm diameter if that makes sense, They are cheapo speakers I know but they have served me well since binning the skytec 15" speakers that were in them for the eminence ones. Now Im looking to simply fit comp drivers to sort that side out, But searching for drivers and x-overs is getting a bit confusing as theres so much choice and difference in price. Thanks for the replies.

Well 1 3/8ths is a standard thread size, Eminence do some rather nice ones that will go straight on, they are very cheap for compression drivers and they are the ones I've used to replace el cheapo drivers in duff chinese speakers before.

Eminence Screw-on Driver

These drivers are around the 20 quid mark and they do the replaceable diaphragms if you manage to blow them. The datasheet recommends a crossover of 2.5 Khz, there is one here in CPC;

crossover 100W

crossover 300W

This can be done but to make things sound good you will probably need and l-pad and some horn eq on the crossover too. Modifying it isn't easy if you don't have the right tools and know how. Sell the cabs and buy something better is my advice.

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Thanks for the advice that is very helpful, My friend is a mobile dj and electrician who has built speakers and old skool light boxes in the past and on the plus side is willing to fit the stuff for me and thinks the cabs I have are worth modifying so I think its worth a gamble, Thanks again

Depending on the type of horn used it is quite possible that it will need some correction in the crossover to sound good. Otherwise you may be seriously lacking in anything 5khz+

CD Horn EQ

If you can stretch to it, the Celestion CDX1-1745/1746 compression driver is a phenomenal sounding comp for the money, far outshining its price tag. The 2 models I've listed are the screw and bolt variants.