Re: Adding cheapo piezo horns to cheapo monitors.
Hello.
If you were to completely disregard "proper" loudspeakerbuilding and sound quality as criteria:
If you were given a crappy 15 inch + compression driver horn loudspeaker with a blown compression driver you couldn't get a hold of a replacement for - and you wanted to replace the horn with something that makes noise... would a piezo tweeter be an option? And how would you connect it in relation to the other components? And what other components next to the piezo would you add?
Having used all the different types of piezo drivers over the years-here is my take and some considerations.
Everything I used was the Motorola version-so I cannot comment on the "current crop" of piezos.
The biggest thing you are going to run into is sensitivity. While the effeciency of a piezo is extremely high-the sensitivity is not so. So depending on the woofer-this may or may not be an issue.
In any case with a piezo you will want to completely bypass the old crossover. Just wire it directly to the input terminals. HOWEVER it is recommended to put a small series resistor between the input and the piezo. 8 ohms or so. This helps at extremely high freq where the piezo is acting as a capacitor-to prevent a very low impedance on the amplifier.
I would first consider one of the screw on piezos for the current horn. There were 2 versions-a 800hz and a 1.8Khz. They both have a little light bulb built in-for some added protection (it doesn't always work) But both of these can handle more voltage (think power if you want to) than the typical "little guy". I would go for the 800Hz version myself-if still available. Then the 1.8Khz
My next choice would be the 2x6. Basically a 1.8Khz driver on a small 2x6" horn.
Then you are left with the 3x5 and 4" round guys-which are pretty much the same-except for size. These handle less than the ones listed above. You can always add more together to make it louder. Don't worry about impedance-since the piezo is pretyy high and will not be an issue.
You WILL have some combfiltering issues-but at this level I would not really care about that.
If you want to increase the "power" (actually voltage) capacity, use several with them connected in a series parallel configuration (4 or 6 with 2 in series-all sets in parallel). This will give you 6dB more "power" capacity". And look "cooler" also.
Depending on which way you go, you may want to disconnect/bypass the crossover on the woofer. If using the horn driver ones I would start by leaving the current crossover in place.
If using the "little guys", I would disconnect the crossover and run the woofer full range.
Yes these are general ideas-but we are not talking about a studio monitor here.
OF course not knowing any more information than has been provided-it is hard to say what would be best-and I don't even know what versions of piezo are available now-Parts Express would be a good place to start looking.
