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Eminence APT-50 super tweeter [message #50695]

Tue, 13 February 2007 19:39

Ken.R
Messages: 8
Registered: May 2009

Esquire

Hi Wayne, awhile back you told me how to add the JBL 077 slot tweeters to my Seven 18's that you designed for me. These are your Sevens that are on Martinellis site. The drivers used are the 2245h, 2123h, 2426h. I added the 077's with the cap and the resister like you told me to with great results. At this time I use the JBL LE85 in place of the 2426h with good results also. I just purchased a pair of custum mini smith wood horns that are hooked up with the Eminence APT-50 super tweeters. Could you please tell me what capaciter and resister I need to use to run this from my Le85 tweeters.
APT-50 SUPER TWEETER SPECS
8 OHM
Power rating 45 WRMS @ 3.5 KHZ
18 DB/OCTIVE 85 WRMS @5.0 KHZ
USABLE FREQ RANGE 3.5 HZ-20 KHZ
RECOMEND CROSS 3.5 KHZ
SENSITIVITY (1 W @ 1 M MOUNTED TO TEST HORN 105 db
Thanks KEN

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Re: Eminence APT-50 super tweeter [message #50698 is a reply to message #50695]

Tue, 13 February 2007 23:42

Wayne Parham
Messages: 18786
Registered: January 2001

Illuminati (33rd Degree)

It's hard to say what crossover to use without knowing more regarding dimensions, spacing, etc. But if this is for super-tweeter "air", you might go with a 2.2uF to 4.7uF series capacitor and see how that sounds. Put a 12Ω to 16Ω shunt resistor across the tweeter for additional damping. If it's too bright, put a series resistor between 4Ω and 8Ω, and if you add series resistance, drop the shunt resistance some too, maybe to 8Ω or so. You'll need more damping if you add series resistance, which will also serve to pad it down more.

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Re: Eminence APT-50 super tweeter [message #50700 is a reply to message #50695]

Wed, 14 February 2007 19:01

dB
Messages: 234
Registered: May 2009

Master

KEN, NICE SPEAKERs/DRIVERs.
(THIS DOESN'T HAVE TO DO TO WHAT YOU ASKED but is related in a certain way: I had this driver and horn I chosed, and I had to ask the lab for a curve of output because it wasn't published for that pair of driver/horn. So I was going to change for another horn when it just arrived after six or more months, last December. Now I have the curves for the two pairs of driver/horns, and I can play with that. As soon as you use different horns you start noticing their different level outputs at different frequencies. The best thing would be to have that curve from the lab for the pair we want to use.) Best Regards

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Re: Eminence APT-50 super tweeter [message #50702 is a reply to message #50698]

Wed, 14 February 2007 22:40

Ken.R
Messages: 8
Registered: May 2009

Esquire

Man, I do not have a clue. I am one dumb shi-. Is there a book I can purchase so I can read and learn. Wayne designed these wonderful cornerhorns and I thought that I could replace the 2426h with the LE85 and all would be well just because they were both 1" drivers. Well I am learning the hard way, the LE85 does not have the output it seams as the 2426h. You see I am a Mechanical tradesmen and I can build anyting out of steel really really nice. Put a driver in my hand and all I know how to do is bolt it to the horn or build some real cool brackets for mounting them. Maybe, just maybe I should not buy anymore drivers and get myself into this stuff. For you guys out there that know what you are doing I hope I have entertained you with some laughter. At least some good has come from this, but I will learn some how. KLUELESS KEN

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Re: Eminence APT-50 super tweeter [message #50706 is a reply to message #50702]

Thu, 15 February 2007 21:57

Wayne Parham
Messages: 18786
Registered: January 2001

Illuminati (33rd Degree)

I wouldn't say you're clueless, there's just no way to know how a driver will act just by looking at it. Same thing with a horn, although there are a few characteristics that can be gleaned by physical inspection. Still, the point is, you can easily make a speaker that makes sound, but to get the tonal balance right takes a little more effort. Mathematical models and/or computers help a great deal, and measurement equipment is handy too. Without them, you're prety much blind and must tune by ear.

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Re: Eminence APT-50 super tweeter [message #50708 is a reply to message #50706]

Fri, 16 February 2007 09:21

artmaster
Messages: 1
Registered: May 2009
Location: Kiev, Ukraine

Esquire

hello! I'm always use this simple equipment for crossover tuning. see the picture - it's easy, but very comfortably.
by the way , what do you think about Fontek ribbon tweeter?
http://www.fountek.com.ua/catalog.php?categ=7&curcod=6&PHPSESSID=4cebba819f787b58da2623622a0837ed

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Re: Eminence APT-50 super tweeter [message #50710 is a reply to message #50708]

Sat, 17 February 2007 00:22

Ken.R
Messages: 8
Registered: May 2009

Esquire

So Artmaster, what is this device you have here and how does it work?

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Passive crossover breadboarding [message #50711 is a reply to message #50710]

Sat, 17 February 2007 11:51

Wayne Parham
Messages: 18786
Registered: January 2001

Illuminati (33rd Degree)

Looks like an interesting way to switch passive components around to make different crossover configurations, similar to breadboarding. What components are in this box and how many configurations does it support? Does it use patch cords for connection or switching? It looks like yours uses switches. If so, are the configrations fixed, (say, second order) and the switches control what passive components are used? Can you switch in different values of dampers, with diferent fixed resisitance values and different capacitor and what not?

I like your test box. It looks like a handy way to swap values. I might suggest using a large breadboard with various size inductors, capacitors and resistors with bannana plugs on each one. With a whole bunch of patch cords, you can build up any crossover configuration you want.

Some would say "go active" and there is merit in that. But if you want to include a passive crossover, you have to design it with the characteristics of the drivers in mind. The reactance, resistance and non-linear properties of the driver interact with the crossover components, so the driver is an integral part of the crossover filter function. This can be simulated with Spice, or you can do it this way, with a physical model and measure the response.

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Re: Eminence APT-50 super tweeter [message #50712 is a reply to message #50702]

Sun, 18 February 2007 09:49

dB
Messages: 234
Registered: May 2009

Master

Nice. Ken,
If you use nice speakers, you can always use the speakers set by Wayne. (I mean) If you use his crossovers (you know what I am talking about right?) and configurations also, you always be O.K.
If you want to change, let's say a driver, make sure it's of the same level (decibel-dB) output and type (impedance, frequency response, etc) than previous; or then change all of them (+ Xover if you want to change the frequencies) to have the same level output on lows and highs. If you have any questions where you want to go or experiment just ask.