# SEAS DXT tweeter is on madisound



## Dangerranger (Apr 12, 2006)

http://www.madisound.com/catalog/product_info.php?products_id=8322


I've been excited about this tweeter ever since I saw it because it solves quite a few problems. When I built Zaph's waveguide TMM design and saw/heard the benefits that the waveguide loaded 27TDFC had over one in a traditional baffle, I felt that this setup would be PERFECT for mating with metal cones, especially the mag cone drivers even in 8" fashion. This tweeter is even easier than that because the flange is smaller and you don't have to worry about routing down the MCM waveguide, making clamps, etc. By the time you shape the response down to what a conventional driver would have, distortion is reduced by a huge extent. It also helps crossover design due to the dome being located further back, closer to the midrange/midbass driver's center. It would even be an effective option for those wishing to mate with an 8" midbass  The Fs is a little higher than I'd hoped it to be, and the driver itself isn't going to be able to be crossed much lower than a TDFC/TBFCG, but crossed in the same region you'll still realize the benefits of lowered distortion and potentially much easier crossover design. The price of these isn't bad either, but they aren't fitting in many cars unless you're putting them in kick panels


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## HIS4 (Oct 6, 2005)

Why is there a dive in the frequency response at 5kHz? Looks like it would sound a little dark.


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## Dangerranger (Apr 12, 2006)

HIS4 said:


> Why is there a dive in the frequency response at 5kHz? Looks like it would sound a little dark.


Effects of the waveguide, boosts the low end response of the tweeter. You'd have to shape the low end response. Check out Zaph's writeup about horn loading a standard dome tweeter. Look at the distortion charts once said waveguide loaded tweeter has been shaped back down 


http://www.zaphaudio.com/hornconversion.html

Standard flat baffle HD:









Waveguide loaded HD once shaped back down to what the flat baffle response would be:









See why I'm excited? The DXT tweeter offers advantages in off axis response as well


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## HIS4 (Oct 6, 2005)

Interesting. The tweeter is extra deep though which might pose some installation problems. 60mm deep ~ 2.4".


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## kappa546 (Apr 11, 2005)

the rise in response between 2-7khz is inherent to the Wave guide design. the point is to normalize response in this area with the use of a crossover and EQ with the added benefit of lower distortion figures of all types in that range and the ability to cross lower.

It seems Seas payed close attention to the diameter and shape of the waveguide to avoid alot of the upper octave nuances in john k's mcm design, while maintaining a low crossover ability. I see a pair of these in my future for sure


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## kappa546 (Apr 11, 2005)

HIS4 said:


> Interesting. The tweeter is extra deep though which might pose some installation problems. 60mm deep ~ 2.4".


yea... while these can be used successfully in a car, the real benefit is for home use imo. the tweeter is now aligned with the acoustic center of the midbass and the added directivity yields a more uniform power response and ultimately a bigger sweet spot.


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## buchaja (Nov 10, 2007)

Interesting thread. Thanks for posting the graphs and the explanations of what we're seeing.

It's the same way Dolby was used to lower the noise of tape recordings. It raised the level of the recorded frequencies involved in tape hiss - around 16k, I think - and then eq'd it back down, which simultaneously lowered the noise.

So can you hear HD at levels represented by the first graph? Especially in the most sensitive range of 3k or so? That's around a 30db improvement with the wave guide, right? Nice.


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## npdang (Jul 29, 2005)

I actually ordered a pair of these already. I've been experimenting with felt rings and the like in the past with good results as well. 

I'm only curious how the waveguide affects the time response of the tweeter. I know some of the diffusers used on tweeters can cause what looks like bad ringing in the time domain.


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## Dangerranger (Apr 12, 2006)

Waterfall plot on Zaphs when compared didn't look bad, it did have an effect but I'd consider the low end boost and the lowered distortion to far outweigh it. Haven't seen more elaborate methods tested of course.


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## GlasSman (Nov 14, 2006)

Those are contenders for a Home Theater Project.

I'll need 5 to 7 of them....group buy?


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## selftc (Jan 22, 2007)

bump...

anyone try out the dxt in a car yet ?


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