AUDAX TW025A12 Tweeter???

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#3
murat said:
Really no one? Specs and money draws no one's attention?
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Dude, take a deep breath. Sometimes threads get missed.

On to the tweeter: 96 db is really efficient, so that's great if you need that sort of thing, but look at the ridges in the spectral decay plot. Ridges mean there's a resonance somewhere in the mechanism, and depending on how long they are they can mess up transparency. The first one looks like it's around 1 kHz, so if your crossover is more than 12 db down there you should be not great, but OK. The second one, at about 2 kHz, is of a bit more concern because it's closer to the specified 2.5 kHz xover, but again if you're running a 4th order Linkwitz-Riley you'll be about 10 or 12 dB down there.

The real problem, as I see it, is the flock of poorly damped decays between 7 and 12 kHz, possibly harmonics of a slight resonance around 3.5 kHz. They look as if they take about 3.5 milliseconds to decay about 25 dB, or about 25 to 40 periods at 7 to 12 kHz. If you plot that out, it's a slowly decaying sinusoid, which means it's ringing like a bell at those frequencies. That might make the tweeter sound wiry in the top end even if the response were flat, which it surely is not on-axis. I suspect the depth and shape of the front plate might be a contributing factor, as it appears designed to be a very short horn, which might partly explain the high sensitivity and the resonances.

Long story short, if you want to try something, buy the tweeter, mill a shallower new front plate for it, and see if you like that better. You'll probably lose a dB or two, but I suspect the top octave will become much more relaxed than the stock item. Fs could also go up a tad because of decreased mass loading, so you want to keep an eye on the impedance peak to make sure it doesn't mess up your crossover. Finally, you might have to get shorter mounting screws to avoid trashing the magnetic structure.


Cheers,
Francois.
 
#4
Francois,

Thanks a lot for taking your time and answering.

I was planning to use these in 3-way speakers, abowe 5000 Hz with 12 db crossover. So, probably I wouldn't care too much about the dips but the points you made about the decay times may be relevant.

The thing is I have seen many waterfall diagrams for the ribbon tweeters but this is the first time I see it for a "conventional" tweeter (at least in my budget range). So, how to make comparison with similarly priced and respected units (like Vifa's) as long as the decay times are considered? Do you have a source of data?

Cheers,

Murat
 
#5
murat said:
Francois,

Thanks a lot for taking your time and answering.

I was planning to use these in 3-way speakers, abowe 5000 Hz with 12 db crossover. So, probably I wouldn't care too much about the dips but the points you made about the decay times may be relevant.

The thing is I have seen many waterfall diagrams for the ribbon tweeters but this is the first time I see it for a "conventional" tweeter (at least in my budget range). So, how to make comparison with similarly priced and respected units (like Vifa's) as long as the decay times are considered? Do you have a source of data?

Cheers,

Murat
Click to expand...

Sure. The partsexpress page for these has a link to "Manufacturer's Specifications", which opened up a PDF with all that good stuff on it. You can also hit ldsg.snippets.org, which sometimes has specs the vendors don't publish.

I'm not saying you'll find decay curves for most tweeters, but hunting around can find you lots of interesting things. Look up the archives here for tweeters - there's an awful lot of smart people who've tried an awful lot of drivers. Bring a lunch.


Cheers,
Francois.
 
#8
Salvaging Audax

Hi folks, first post on here so bear with me 😀

I bought some DIY floorstanders of Ebay and to cut a long story short, i was'nt impressed at all!

I went on very little and was basically hoping they would be good as i have previously heard Audax drivers and been very pleased.

Cabinets were made of chipboard and not very well constructed at all, they include........

three 6" - Audax HT170F0 and 1" tweet - Audax TW025A1 in each speaker, I have since purchased other speakers which i am very happy with so was hoping to use the above an try to make some surrounds and maybe with a purchase of one more tweeter a centre channel as well. Do you know anywhere that would work out the size of the box needed for the surrounds and work a crossover to suit the above drivers??

Thanks for your help
 
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