Super tweeters

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#3
Try to find a couple of basic frequency response plots when you can. A lot of drivers have very, very erratic response.
My feeling has always been that if they don't show you a graph, there's something they don't want you to know. I'll make an exception if the manufacturer gives really tight specs like 3kHz to 20kHz +-.5dB. But when was the last time you saw something that tight?
That said, I've always had a soft spot in my heart for super tweeters in much the same way that I love subwoofers. If I weren't so happy with the ribbon tweeters I have now, I'd probably have some kind of super tweeter tagged into my system. Then I'd be quint-amped like Nelson and have to build another amp.
Oh, gee...another excuse to build an amp...just what I need.

Grey
 
#7
The ribbons are the ones from my old Magneplanar Tympani IVs. Five feet long, single element, direct drive (i.e. no transfomer), purely resistive (kinda low--about 2.5 ohms), and sound like a dream. I cross them over at 5kHz, 6 dB/oct. I jettisoned the Maggie midrange, which wasn't on the same level as the tweeter, and am currently using the Bohlender-Graebner RD-75s down to 250Hz. Then I go back to the T-IV woofer panels for a little bit, then to the twelve 12" subs at 70Hz.
Those last two crossover points are going to be moving downwards and probably to 12 dB/oct (they're both currently 18 dB/oct), but that's going to take more work.
<i>Sigh</i>
I'll get there one of these days.

Grey
 
#8
This could be it?

<a href="http://panasonic.jp/car/av/products/SPEAKER/CJ-ST300D.html"><img src="http://panasonic.jp/car/av/products/image/photo/CJ-ST300D.jpg"></a>

Bablefish gave this translation from the Linked Page <font size="-2">(click Pic)</font>:

<hr width="95%" align=center><i>Leaf tweeter -
Without stress to the 80kHz the extension,
To delicate nuance of high pass in upper quality playback.
The CD and the MD, furthermore the high pass which is recorded in DVD audio, compared to the clearness being, more transparent impression the leaf tweeter which is played back with the sound which overflows -. It acquires playback zone to the 80kHz. Attendant upon that detail of sound and the air impression of the sound field vividly playback. In addition to being like the silk, high pass of quality is actualized, the grade of the system is made to raise largely.

CJ-ST300D
* Specification
impedance: 4 Omega
- rated input: The 35w (network it is attached)
- instantaneous largest input: The 130W (network it is attached)
- output overpressure value: 87dB / w.m
- playback frequency zone: 5 - 80kHz
- crossover frequency: 10kHz (6dB / oct), 8kHz (12dB / oct)
- external size: W36×H65×D14mm (tweeter -) / W65.5×H34×D120mm (crossover network)
- mass: 90g (tweeter - 1) / 140g (crossover network 1) </i><hr width="95%" align=center>


While looking I found this curious object
<a href="http://panasonic.jp/car/av/products/2DIN/CQ-TX5500D.html"><img src="http://panasonic.jp/car/av/products/image/photo/CQ-TX5500D.jpg" ></a>
Looks like a 6DJ8 in the middle their?


Regards
James
 
#9
I looked at the graphs for those two tweeters. The rectangular one would be a nightmare to try to work with; response curve like a saw blade--probably cavity resonances behind the front plate. But the round one...now that's real workable. Put a 6 dB/oct highpass on that thing to take that long straight climb out of the picture and you're going to have nearly ruler-flat response. Very interesting, indeed.

Grey
 
#13
Do you mean the Lineaum ribbons?
Click to expand...

The ones I was thinking of were called Optimus Dipoles, a Tandy/RS add on ribbon tweeter that had its own built in crossover, ( a first order cap at about 6K, if I remember correctly), and so, as you say, conected directly to the speaker leads.

From what I remember they were very insensitive, and had a very ragged frequency response. I was not very impressed, I think I sold them as soon as I could.
 
#15
Re: Antiques By Now...

mrfeedback said:
"Do you mean the Lineaum ribbons?"
No, much older than that - not sure if they were dynamic or maybe even piezo - I forget.
I don't think they were particularly clean, but they did add that HF 'air'.

Eric.
Click to expand...

Well, they did have piezo that sat on top. But as I recall, they had a rather attractive chrome plated horn type tweeter that sat atop the enclosure as well.
 
#16
Is this the one you mean? They still have it-part number 40-1310. Interesting response chart too-over 90 dB to almost 50 Hz. 98 dB from 10K to 20 K.
 

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#17
I think this is what Thorsten used with the Eminance Beta 12" whizzer cone version to create a cheapo Hammer knock off.

It appears to have the perfect response to spice up a Fostex full range also

How does it sound? I wonder how much we can tell about tweeter sound over 10k other than gross response curve variations? Probably enough to say that there are better choices out there!! Can you post the chart? Does it have a level control (l-pad)?
 
#18
Post the chart? Why not?

No L-Pad supplied, but they do recommend the use of one.

Here is the link here:
http://support.radioshack.com/support_audio/doc66/66180.pdf

It is supplied with a 2nd order network. Even with a second order network attached, though, this thing looks ready for a first order crossover around 5KHz. Unfortunately, no dispersion charts. Which, as Grey pointed out earlier, makes one wonder if they are hiding anything.
 

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#20
Well Done...

kelticwizard said:
Is this the one you mean? They still have it-part number 40-1310. Interesting response chart too-over 90 dB to almost 50 Hz. 98 dB from 10K to 20 K.
Click to expand...

YEAH, that's the ones - now that I know what they look like, I just have to find which box they are in. 😀
In the Eighties they looked impressive, so they 'HAD' to sound good - nowadays the first improvement would be to ditch the internal bipolar crossover cap and give it a PP - now I'm getting more interested in finding them again.
Dave, I agree those little tweeters are not bad really, if you cross them high enough, I'd say - old Sanyo 3in1 boxes used them mostly I think.
I have a pair of old Pioneer diecast horn tweeters in cabinets in the garage - these are great little tweeters too if you can find them. 😉

Eric.

KW - thanks for finding the pdf.
 
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