piezo tweeter question

[zobsky]

I'd like to utilize 2 rear-firing piezo tweeters crossed over high (somewhere above 10 - 12KHz) to complement a single fostex FE166 ES-R widerange driver ( a single piezo doesn't match the widerange efdiciency).

The article on the diyaudio wiki reccomends a 22 ohm resistor in parallel with the piezo and an appropriate blocking capacitor in series

question: does the above reccomendation change if i parallel two piezo tweeters ?

[Cal Weldon]

You're firm in the use of piezo's?

Cal

[zobsky]

Originally posted by Cal Weldon
You're firm in the use of piezo's?

Cal

not dead set on them, but they are the cheapest option available locally ($1 - 2 each) at a reasonably efficiency (the fostex is around 95 - 96 dB efficient in a rear horn), ... and they are for a rear firing "ambience" application, so an expensive ribbon might be overkill

do you have any other suggestions meeting my requirements(MCM did seem to have a bunch of not too expensive bullet / horn tweeters)?

thanks,

[Andy G]

a $2 piezo will sound like a $2 piezo !! better your ears than mine !!

[jdybnis]

I think this is an interesting question. What makes a good rear ambiance tweeter? Wilson uses a Scan Speak ring radiator in their $50k MAXX. But at $480 a piece that's out of the question for most situations. The "audiophile" super-tweeters from PHY, Tannoy, etc. are almost just as expensive.

How about one of Audax's 10mm dome tweeters? http://www.audax.fr/

[zobsky]

just for kicks, i bought 4 of these tweeters this evening for the ungodly sum of $1.89 each , along with a few film caps and 22ohm/2W resistors.

i already have another identical piezo tweeter whose element has previously been annoited with a light dose of spray damar. any future sacrifices in the interest of advancing human knowledge will be performed on this lamb. previous tests with this tweeter were not too bad, .. (the other tweeter used as a comparator in that experiment was a Aurum Cantus tweeter (perhaps 94dB eficient, IIRC), .. somewhat better, .. but definately not 50 times better. that's all i can say to the "$2" post above). I'm looking to get above 95dB for this application, as I expect losses due to wall bouce, and hopefully these give me a reasonable chance to succeed at that.


as i mentioned, .. this is for a ambience supertweeter application crossed way up, not a dedicated tweeter crossed low.

watch this space and thanks for the suggestions

[Andy G]

maybe try this instead !!

http://www.allenorgan.com/store/aostore.html

if link doesn't work try..

http://www.allenorgan.com/forsale/fo...hFacePlate.pdf

[planet10]

Originally posted by zobsky
question: does the above reccomendation change if i parallel two piezo tweeters ?

The 22 ohm R dominates so 1 or 2 piezos shouldn't make a difference.

Don't let the naysayers disuade your experment. Piezos get their bad rep from being used without a proper XO, which makes the tweeter sound rough and usually drives the amp nuts.

Pursue the treatment of the piezo cone (they can be used naked) and if you use the horn ductseal it.

dave

[Andy G]

I generally have nothing against piezos either, but have found the cheap ones sound just that, cheap, no matter what you do with them.

Pity the Motorola/Cts ones are no longer in production , I have found them as good sounding or better than a lot of compression PA drivers for that application, on the proviso you use a simple x-o on them and don't use them without an x-o !!

Also I have seen some of the cheaper version advertised as 8ohm, maybe that implies there is an internal resistor in place already, in which case the 22ohm resistor would have little effect. So be aware what you are actually using !!

[Andy G]

Originally posted by Tim__x
I may be mistaken, but I seem to recall that some company purchased CTS's intellectual property rights and is making pizeo tweeters based off of CTS designs.

That would be nice !! Ifyou find out more, please let us know !!