INTRODUCTION
I have different types of drivers from various manufacturers since I like to try a number of things. This simple project is a way for me of letting go some older drivers in good shape as replacements arrive.
Though Piezos are not "noble" and snobbed by some, they're still known drivers, of low-cost that can produce acceptable sound if they are properly accompagnied by a simple crossover network.
Motorola did sell tons of these not only for individuals, but also to some known speaker manufacturers, as well as less known ones, and still counting under other names (back on this later).
Among known manufacturers who used these: Community, Peavey, Fender, Sun (piezo source). They can't be all stupid in my view, though admittedly not high-end drivers, but can still do the job adequately. Motorola Engineers published in the JAES about their invention or discovery in 1975 if I recall correctly, and their specific design is patented. My understanding is they are deemed to be the high-end of piezos.
Motorola's most famous being the KSN 1005A 3 1/2" Super horn tweeter, which I'm tempted to call somewhat of a "poor man's version" (not a copy) of a 2402 for example. JBL Selenium Brazil did make lower cost "copies" of the latter, such as ST200, ST-304, ST-400, and ST-350 (50°X50°), as well as Sammi (China?) HF 200A, and of 2405 as HF 250.
The pair of boxes in the making are low-cost ones for the neighbor's ambience music outside on the deck/near the pool. No pretention of being great high-fi or sound reinforcement cabs. Attracting rave reviews isn't the intent, rather just sound ok in the particular context (e.g. city noise). Simply a fun project.
Btw, the two-way pair of speakers are given to him absolutely free. There's about $60+. of material per box, and my time. The main purpose of the project being to say goodbye to some working drivers that I didn't want to throw away, the same logic applies to other materials in stock such as plywood leftovers from other projects that can be used for smaller box sizes.
Last but not the least, these boxes should sound better than the table radio's bad sound he's projecting when making his pool and deck gatherings. So, in a way its an "investment"...
Of the six piezos I have, 4 of them are 1005 type (2X 100% original Motorola I keep; 1 "semi-original" Motorola given to me- element replaced with OEM?; 1 Asian copy available purchased to make a pair, the latter two going in the neighbor's boxes-see below), plus two KSN 1025A 2X6" mid/high horns, 75W, that are 100% original Motorola. They also made a high-power "Powerline" 400W version of this one. I'm first owner of all originals purchased new. (Back later on Motorola original VS others...).
Since Motorola originals cannot be purchased anymore (with a nuance), contrary to a large number of cheap "copies", I didn't want to give here (see below) "knock-offs" that anyone can easily purchase by themselves, plus for neighbor's use of the boxes it won't make much difference re ambient noise...
If someone wants the latter two 1025 type originals they are available for FREE, packaging included, shipping cost excluded. Since these are light and relatively small, shipment cost should be low, the carton they're in now/for shipping is about 0.25 cubic foot. Tested them today with music, still work ok, good condition. If interested to play with these just let me know by private message or in the thread. Actual ext. dimensions: about 3 X 7.5 X 4" deep. Then 4 of them will be gone, I keep only 2 X1005 originals.
If a person doesn't feel familiar enough "electrically" speaking to play with these, no problem as I can also provide free easy to read technical and simple crossover info on these from Motorola and others, including from a Peavey Loudspeaker Design Engineer. Though many people on the net have their own "recipe" on this, good or bad, I prefer to pass along the real thing from acceptable makers.
In follow-up article, as it comes, I'll describe with some detail the project parameters/tech info. Even if its a low-cost project, to me it's not just a matter of throwing a bunch of components together in a box. There's still some modeling, tweaking and testing work and choices/decisions to be made: e.g. though they don't REQUIRE a crossover, they perform/sound better and accept more power with a simple one... Regards,
Richard