omnitronic DX-2222, 3 way speakers but crossover circuit

[SteveAATW]

The signal isn't just 'split' at that frequency - it rolls off at 6dB per decade from that point. ie, everytime the signal frequency divides by 2 below that point the amplitude will decrease by half. Thus you will still have some signal @ 300Hz, 200 Hz, 100Hz, 50Hz etc in the signal to the horn/piezo, it will just be attenuated.

 

The break frequency is given by 1/(2 x pi x R x C), though that's an ideal approximation and the real figure won't be exactly the same and will vary with temperature.

 

You could build a new crossover, you could tri-amp it and feed it via an active crossover and multi-amplifier setup but ultimately I would stop and think about what improvements your going to gain from modding that cabinet - as a wise man once said to me, you can't shine turds.

 

If your after better performance you'd be best off looking at getting some new speakers. There are some affordable 2 way boxes which will sound so much better - you don't have to spend silly money to get something approaching decent sound.

[SteveB]

Paul,

 

To find a crossover in such a cabinet is unusual. Without listening to, or measuring the cabinet it is hard to say whether it improves the performance of the cabinet or not. The use of the horn and super horn (CTS’ description) is probably done more for looks than performance.

 

Some information about piezos which I have written can be found at the following link.

 

http://www.burton-manor.co.uk/Audio/piezo.htm

 

For more detailed and the authoritative information, scroll to the bottom of the page and click on the link to CTS’ application notes. CTS by the way are acknowledged to make some of the best piezos available. If you read and understand this you probably know more than the people who built your speaker and it gives the values of components needed if you do intend to optimise each horn.

 

One of the problems with piezos is their low sensitivity (compared with compression drivers) and I have found that the 2K horn (looks like the bigger one in your cabinet) works OK with a single 8” or 10” drive unit. If you follow the link to my web site and then use the menu on the left to go to the Audio sub menu and then follow the bottom link “Miscellaneous” there is a frequency response plot of such a horn wired in parallel with an Eminence beta 10, for which the sensitivity is about right. Don’t take the article to seriously it is not meant to be.

 

Back to your predicament and a bit of rambling. If it was me I would first disconnect the tweeters and listen to the 12” drive units on their own to determine how much mid is being rolled off by the inductor of unspecified value. If possible plug your computer’s audio out into your system and do a search for a signal generator so you can do a frequency sweep to give a better indication of this. If the output you hear starts dropping off before about 2.5 to 3 KHz the piezos won’t cover it and there will be a dip in response in what I would describe as the upper mid. If this is the case I would wire one of the 12” speakers directly to the input and have a listen to the result. It might be better or worse but it is safe to do and is easy enough to put back if it doesn’t work.

 

Feel free to ignore any or all of the above as you see fit.

 

Steve.

[Ste69]

I was interested in these speakers as I found them on ebay for £150 a pair, but after reading this im not so sure whether they're worth getting after all. Have the problems been sorted out or have you just replaced them?

 

Edit: spelling mistakes

[monsterer]

Feel free to ignore any or all of the above as you see fit.

 

Steve.

 

Thanks a lot steve - I love practical advice like this, thanks for taking the time... :) I'll look into it and post the results back on here.

 

 

was interested in these speakers as I found them on ebay for £150 a pair, but after reading this im not so sure whether they're worth getting after all. Have the problems been sorted out or have you just replaced them?

 

I brought mine for £110 delivered (for both) so its not a total loss that the midrange is a bit weak :) I would love to be able to improve it though, the bass is very nice :)

[Ste69]

Where did you get them from?

[monsterer]

Where did you get them from?

 

ebay - a german ebay shop called elekronic-star was running lots of 0.99p start, no reserve auctions for these speakers... They still are AFAIK.

 

e 2K horn (looks like the bigger one in your cabinet) works OK with a single 8” or 10” drive unit. If you follow the link to my web site and then use the menu on the left to go to the Audio sub menu and then follow the bottom link “Miscellaneous” there is a frequency response plot of such a horn wired in parallel with an Eminence beta 10,

 

Hi Steve,

 

Where did you get that program which plots the frequency response graphs? I would be interested to see how these speakers perform - do you just need a microphone and the software?

 

Cheers, Paul.

[JordanSteel]

Think yourself lucky, I bought a pair of Auna DX2222. Same speakers just marketed by a different company look at this for appaling quality:

 

http://i905.photobucket.com/albums/ac260/J...um/IMG_1384.jpg

[Simon Lewis]

...Think yourself lucky, I bought a pair of Auna DX2222

 

Welcome to the Blue Room.... However, you might have noticed that the last post in this thread was in August 2007?