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Multi-Way Conventional loudspeakers with crossovers

Piezo VS voice coil tweeters
Piezo VS voice coil tweeters
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Old 18th September 2004, 07:10 PM   #21
zed is offline zed  Sweden
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I have built a Worldaudiodesign design KLS3 Mk II gold utilizing above mentioned Audax tweeter HD3P tweeter.
It produces a very sweet and distinct treble quality. Regreatibly it seemes not to be in production any more. Non horn design, kind of dome where the gold layer (on the polymer) is a motor.
Meadowlarks speaker company (among others) had the driver in their top of the line model once.

So: the piezo pricncple has a potential to develop!
Regards
Dimitri
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Old 18th September 2004, 10:12 PM   #22
PeteMcK is offline PeteMcK
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Default near field listening?

I don't think anyone's considered whether horn tweeters are appropriate for near field listening? They would be efficient, which is good if you're driving them from the sound card, but if you're close to a horn tweeter they may not blend with the mid/bass driver that well?
Anyone's experiences with these would be appreciated, I've got a pair of Piezos & a pair of EV horn Tweeters which I haven't thought of a good use for yet.
Pete McK
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Old 18th September 2004, 10:36 PM   #23
ThorstenL is offline ThorstenL  Germany
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Default Re: Piezo vs electromechanical tweeters

Konnichiwa,

Quote:
Originally posted by polsol
At first glance, a piezo tweeter would appear to be ideal for the HF section of a speaker system because it does not require a XO.
The statement "Piezos don't need crossovers" is misleading. They do not need them to be protected from low frequencies, the way dome tweeters do, but in the acoustic sense they need the same sort of approach to integrating them with the other drivers as any other Tweeter, except of course electcally they appear as capacitor which has implications o the croosovers practical implementation.

Used correctly Piezo Tweeters, even the Motorola/CTC PA "Lemonsqueezer" can be quite good to very good.

Sayonara
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Old 18th September 2004, 10:47 PM   #24
sek is offline sek  Germany
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Also in the interest of the thread starter, could you suggest how that could be approached, please?

I've got two Motorolas laying around. But I have never heard them sounding good, and I had to stand them quite often.

Of course, piezo tweeters - while 'safe' - are sonically useless without crossover. The usual recommendation would be to connect a resistor in series, this 'lowers' the series impedance of the two and let's the resistor-piezo combo look alsmost resistive for low frequencies. People then usually put the usual crossovers in front of them, calculated for the (almost linear) impedance of the series resistor.

But I have never experienced this to sound goot, neither in so called PA systems, nor with my particular piezos.

Thanks,
Sebastian.
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Old 27th October 2004, 12:46 AM   #25
carlosfm is offline carlosfm  Portugal
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I use Motorola rectangular piezos on my forth system, on the basement.
They sound like a million dollars, but some years ago I've spent a lot of time testing components and tuning a crossover for them.
Without a crossover or with "standard" values for a crossover they sound horrible.

They have a very fast (oh so fast...) and detailed sound, it really reminds a live performance, the real thing.
They have to be crossed over quite high to sing like this, and attenuated to match your mid/woofer.
Only this way they produce gorgeous midband and treble.
I would have to open the speaker to see the component values I used, but in my head, from what I can remember, it's something like this:
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Old 27th October 2004, 12:48 AM   #26
carlosfm is offline carlosfm  Portugal
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Oh this is the tweeter, but mine is a genuine Motorola.
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Old 27th October 2004, 01:36 AM   #27
Cal Weldon is offline Cal Weldon  Canada
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Piezo VS voice coil tweeters
Carlos,

That's the one I was talking about in post #5

Those actually sound OK. It's the one that I used with a coil in series along with a pair of 12" woofs in a cheap and dirty 2 way. Surrey speakers if you will. (local humour)

I think mine were Motorola's as well. That's the best sounding piezo I've heard.

But it's still a piezo

Cal
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Old 27th October 2004, 01:39 AM   #28
sek is offline sek  Germany
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Thanks, Carlos.

I didn't investigate this further back then when I was at it (I was only 16 when I bought them, my god, long ago!).

My assumption has alway been that it's wiser to approach piezo tweeters similar to normal ones: Attenuate the piezo's sensitivity with a divider that in turn poses a low impedance load to the amplifier. Then match a high pass with it and experiment from this starting point on, towards a cut-off point and an acoustical filter slope that fits the system. That said, your filter looks really genuine with 560nF and 1:1@33R.

I gave up when I realized that it seems impossible to get their distortion down at frequencies in the midrange, like until below 4kHz. I liked their sound at 'ultra high frequencies', but couldn't match them with a low-mid unit in a two-range system.

Sebastian.
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Old 27th October 2004, 01:59 AM   #29
carlosfm is offline carlosfm  Portugal
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Quote:
Originally posted by Cal Weldon
But it's still a piezo
Cal
Yes, but with this crossover, after many hours of fiddling, I've got a sound from them that is, really, quite good.
It's a different sound from a good dome tweeter, yes.
But it's just different.
Some people may not like, other people like me and others who I've showed these tweeters playin' get quite amazed at the speed and detail they can produce.
I have them on standalone small rectangular wood boxes, I can take them everywhere and connect them to any speakers I want, preferably with double binding posts so that I can easily disconnect the speaker's tweeters.
On this system I use them with cheap fullranges.

Quote:
Originally posted by sek
I gave up when I realized that it seems impossible to get their distortion down at frequencies in the midrange, like until below 4kHz. I liked their sound at 'ultra high frequencies', but couldn't match them with a low-mid unit in a two-range system.

Sebastian.
They work very well with fullranges.
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Old 27th October 2004, 02:03 AM   #30
sek is offline sek  Germany
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Quote:
Originally posted by carlosfm
They work very well with fullranges.
Yes, but they look very ugly with fullranges.

Anyways, I kept them by intention. Their time will come, even if it's in someone else's boxes.
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