HI everyone !!

i m lookin forward to built a tweeter box for a reggae dub sound system...with piezos i think...i didn find any plan to built a tweeter box with approx 10 piezos.

does someone have some plan to build this ??

dont need so many piezos..but look pretty nice no ??;)

thanks man1000

and what kind of piezo is the best?

 is there a specific model thaht is better than others?

and what should i absolutely ban ?

 

Edited by Jahm - 16 November 2005 at 10:17am

Ive got about 30 Piezos left over form a project, i didnt need as many as i thought.  I would be happy to sell them for about £2 each if your after some. 

Vertical piezo arrays work better than horisontal as you get much less beeming and comb filtering.  I did mine as shown on thses cabs:  http://www.billfitzmaurice.com/plans/pro duct_info.php/products_id/3?osCsid=73d2d9b07ea078c4f970b9bd1 ca1911e

The top end sound really nice, far better than i expected.  You can trim the frames so that they couple better but i didnt bother, its mainly so you can fit more in.  I would recomend these cross fireing vertical piezo arrays they have nice wide dispertion.

what im lookin is more some advice about wich type of pizo is good or not.

what should i ban?

what would "do the job" for a typical TSSS TSSSS CHHHHSSS piezo top sound

Just hurts my ears--looking at that. Every time I heard piezos they sounded harsh and ear splitting and my ears ring loudly for about 3 days after.

If you must use piezos dampen down the harshness of them.

http://members.misty.com/don/pzfix.html

Cross them over at 8-10khz or they sound as harsh as sh*t.

 

• 8 ohm resistor across the piezo terminals 
• 0.47 uf capacitor wired in series

I also experimented with damar on the piezo’s cone element. In my opinion, this added refinement to the sound and reduced sibilance almost completely to my ears.

1. Remove the three screws from the back of the piezo
2. Coat the paper cone with one coat of damar
3. Remove ‘pooling’ of damar with a tissue
4. Let dry overnight
5. Reattach horn
6. I also applied rope caulk to the back and sides of the horn to deaden any plastic sound.

Making piezo tweeters sound better!

• Use of Series Resistors
• Use of Damping Material
• Use of Crossovers

Use of Series Resistors Adding a series resistor greatly improves most uses of piezoelectric tweeters. Adding about a 47 to 50 ohm or so resistor reduces the extreme treble response by about 3 dB at 20 KHz, and by about 2 dB at 16 KHz. Lower treble frequencies are less affected, but the effect is great enough to consider the sensitivity reduced by 1 dB or maybe slightly more. If the effect is not enough to tone down the "hissy" nature of most piezo tweeters, then use a slightly higher value resistor. However, you should not have to go over 100 ohms, since this has quite an effect on upper treble frequencies.

The KSN1025 tweeter and its relatives (including Radio Shack 40-1379) have an internal resistor of 30-33 ohms. It may be good to add about 10 ohms to this. Please note that this model has about double the usual .15 or so uF of capacitance.

For general home stereo use, 1/2 watt resistors should work. For professional duty applications, you need power resistors. This even means shorting out the internal resistor in KSN1025 tweeters with a thin piece of wire and using external power resistors.

One advantage of adding resistance is an increase in power handling and reliability.

Use of Damping Material The back of piezo tweeters is generally removable. This permits you to stuff in a bit of fiberglass between the diaphragm and the ceramic piezo element, as well as behind the ceramic piezo element. This somewhat damps down a "harsh" resonance around the lowest frequencies that piezo tweeters work at.

With most models other than the KSN1025, you may need a bit of a trick in order to put the tweeter back together. The trick is to solder thin pieces of wire to the ceramic piezo element leads. There are holes in the terminals on the back of the tweeter, although they may be filled with solder. You can unplug the holes and thread the added wires through.

Use of Crossovers Although piezo tweeters are widely used without crossovers, you will gain some power handling and reliability if you remove frequencies out of their range. You may even slightly reduce some of their upper midrange/lower treble harshness in the process.

Edited by ToXiC - 27 December 2005 at 10:46pm

what tweeter would you suggest if i wanted to build myself an array liek that?  i have been wanting to build two small boxes with eight 8 ohm tweeters in each for a while now but still cant aford it (by summer i will however...)  i cant stand piezo myself, and say i want a tweeter that goes up to 18k or maybe 20 k.  what would i need?

oh yea does size even effect response on boxes full of tweeters?