Seas Tweeter tbcd/gb-dxt

[Silversmoky]

Just noticed this tweeter on Madisound in the new products. Was wondering if this is a new tweeter from Seas or if it is just new to Madisound? Curious if anybody knew anything about it. I like the looks of it from a visual standpoint.

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

[Mazeroth]

I remember Zaph posting about this fella months ago but it wasn't out at the time. All we had was a .pdf from Seas to go by. I'd be curious to see how the distortion on this pans out when a crossover is implemented due to the increased output below 10 khz.

[Jed]

Cool. I'm gonna order some now. Should be an awesome tweeter with great power response and dispersion characteristics. :T

Been waiting for this one for awhile. An interesting collaboration effort from DXT and SEAS.

http://dxt.dk/pages/webside.asp?articleGuid=35007&menuGuid=15292

Jed

[Jonasz]

According to Zaph's blog a test is imminent... ;x(

[augerpro]

Hmmm the faceplate is no bigger than a regular tweeter, how effective can the WG be? I thought there was a bigger version that Zaph was more interested in?

[ch83575]

Hmmm the faceplate is no bigger than a regular tweeter, how effective can the WG be? I thought there was a bigger version that Zaph was more interested in?

I think I remember seeing a slightly larger version as well. If I recall correctly it looked mostly deeper, but also larger diameter.

Looking at the spec sheet it doesn't look like they achieve a constant directivity until around 4k-5k... not exactly what most people around here are looking for. I think to push the constant directivity down to the range where most people in this forum are crossing over would require a much larger WG.

Maybe I am missing something though. There isn't really that much off-axis info presented by the spec sheet.

-Chad

[Nemophyle]

yeah i wonder about that too auger

loading seems huge still according to the datasheet for such a small waveguide, still interresting for small systems

but i despise the fact that the other version simply disappeared

maybe we could ask seas about that ?

also the sharp diffraction edges, patented to the dxt technology makes me wonder. It's supposed to be calculated so it matches hi freq dispersion with mid band dispersion. I just wonder if it's real or just marketing BS. THe measurements on dxt site looks good though

http://www.dxt.dk/

[Jed]

A few people measured these tweeters in Europe and it was stated to have a very flat off axis response and excellent power response characteristics after implemented in a simple system. This tweeter is going to be great because you can cross a bit lower than usual with the standard tweeter and still lower distortion because of the boosted low end. Yeah it might not compete with a larger waveguide, but it definitely has some advantages and the dxt technology is very real if the published specs are believed. Most of the time Seas is pretty accurate with that so rest assured.

I'll know more Monday when my pair arrives.

[Nemophyle]

exactly what i was thinking about this small thing. Even then it would have been nice to have the larger version too.

although i fear it's just never gonna be released. It's easy to see how it's not as viable commercially as the smaller alternative.

[jkrutke]

exactly what i was thinking about this small thing. Even then it would have been nice to have the larger version too.

although i fear it's just never gonna be released. It's easy to see how it's not as viable commercially as the smaller alternative.

Seas had a 6" version on display at CES last year. The company who they licensed the tech from had used it in a design with a couple of L18 woofers. I wouldn't count Seas out of making a larger one someday. I had heard that they wanted to do 2 versions, a Prestige and an Excel. Of course, if the Excel version is going to cost $260, they may as well not bother.

Personally, waveguides of any size have value. Even the 1/2" rear mounting method I did for the D26NC55 has performance benefits over the normal flange model. Anyway, I have the DXT here and I'll likely take a look at it this weekend.

[augerpro]

Anyone know how to get a hold of these?

http://www.peerlessaudio.com/newpdfs/T28SG%20LFS%20with%20waveguide.pdf

[Dennis H]

Maybe email Peerless India and ask them if they have a dealer in the US? I think Danny Richie OEMs some of his drivers from them but I don't know if he can get the retail stuff in small quantities.

info@peerlessaudio.com
info@gr-research.com

[jkrutke]

Just finished my testing of the DXT, not too bad. Jed, we can compare results and maybe get some more consistency data. (see the impedance plots in my blog) Check out the off axis plots and filtered HD plots.

I've been toying around with swapping the 27 and 29 series motors with no real benefit shown so far, but I have a feeling I might like the DXT better with the 27 series motor. I'll give it a try. Of course, for those who might like how that turns out, it becomes an $80 tweeter since you have to buy a 27 series to get the motor. Still worth it, IMHO.

[jkrutke]

Anyone know how to get a hold of these?
http://www.peerlessaudio.com/newpdfs...0waveguide.pdf

Weird, the response doesn't show much low end rise. It appears the waveguide is too shallow. I'd sooner get my hands on the Monacor WG-300. Too bad there are no US distributors.

[jdybnis]

Maybe the tweeter is designed with a rising response to compensate for the waveguide loading. The efficiency is pretty high for a 8 ohm tweeter.

[Silversmoky]

Just checking out Zaph's tests a little. I am impressed with the off axis response. That's pretty amazing at 30 degrees off it still has changed very little. Seems to me that it will definitely have some uses.
Is this the same technology or idea that the newer morel tweeters are using too?

http://www.partsexpress.com/pe/showdetl.cfm?&Partnumber=277-070

http://www.partsexpress.com/pe/showdetl.cfm?&Partnumber=277-074

[mlw]

Morels "IDR" and seas "DXT" look different, and even without the $190 per pair price difference the seas looks more interesting to me. I am waiting patiently for those more knowledgeable than I to discuss possible applications of the tbcd/gb-dxt.

[Kevin Haskins]

Its a step in the right direction. Your not going to see constant directivity to our typical dome tweeter crossover points unless they get much bigger, I don't see any way around that. The advantage of this is it fits in a standard tweeter cut-out. Companies can change designs slightly, and have the marketing mojo of CD.

That large break-up out of bandwidth is a mountain! Maybe they should have used a stiffer metal dome or ceramic and pushed it up a little further.

Their marketing graphs (DXT) are just that.... I'd ignore them. They don't look like real data.

What I'd like to see is some comparisons with compression drivers & CD horns. Zaph?

[Jed]

Morels "IDR" and seas "DXT" look different, and even without the $190 per pair price difference the seas looks more interesting to me. I am waiting patiently for those more knowledgeable than I to discuss possible applications of the tbcd/gb-dxt.

I'll be testing my pair sometime this week. Just got back from NYC last night and had a nice pair of DXT tweeters waiting for me. As for possible uses, there is a possibility for a LR2 design with this tweeter at 2.5K, crossed to something like the TB W4-1337 in a 2-way or 3-way situation. I've also got a pair of Seas W15CYs I've got to do something with. I like John Krutke's idea of using the ferrofluid loaded motor of the 27series so one could cross even lower with reduced distortion and smoother response. But, I plan on seeing what this tweeter can do without modifications first. No ferrofluid has its advantages as well. Some say removing the ferrofluid allows more detail through the useable signal range. This might have some merit if you look at the latest trends by Accuton, where they are using less ferrofluid and neomagnet structures in the more advanced drivers. The downsides of no ferrofluid is less power handling, a bit of a weird impedance hump, and a rise in distortion as you go lower in frequency. The nice thing about the DXT lens is it allows one to cross lower because of the boost you get from the waveguide, thus "fixing" some of the issues one might have with a normal faceplated version without ferrofluid. The benefit then is the ability to cross lower than usual with less distortion, more detail because of the motor design without ferrofluid, and all the other benifits of a waveguide with acoustic center alignment etc.

It's a pretty cool driver in my opinion.

So maybe you guys could figure out what you would like to see with this driver.


Here are some of my ideas:

Maybe something like DXT, W4, Dual RS225s? LR2 design?
DXT, Seas W15CY, Dual RS225 or RS180 in a Watt Puppy enclosure?
DXT, Dual W15CY open baffle, Dual Seas L16 ported in a slim ported enclosure?


Later,

Jed

[JoshK]

DXT, Seas W15CY, Dual RS225 in a Watt Puppy enclosure?
Jed

That sounds like a cool project. :T

[Jonasz]

I vote for DXT, W4 and RS270. Second choice would be DXT, W15, RS270.

BTW, why is the RS270 not used in any designs around here (apart from cjd's threeways)?

I brought the RS270 around the world so pleeeze I hope anyone build something with it! :B :rofl:

[---k---]

I'm somewhat disappointed and surprised by the fact that the DXT can't support a real low crossover point. On this point, it is worse than the current favorite SEAS tweeters and the RS28. I thought that this was 1/2 the reason for a waveguide. Any thoughts?

Jonasz,
The RS270 is a great driver. CJD had some of our's jaw on the floor last weekend with the bass it was producing in a sealed config. It is just a BIG driver and likes BIG boxes. Most of the projects you see are smaller to meet Wife/Spouse approval.

[Jed]

I'm somewhat disappointed and surprised by the fact that the DXT can't support a real low crossover point. On this point, it is worse than the current favorite SEAS tweeters and the RS28. I thought that this was 1/2 the reason for a waveguide. Any thoughts?

One thing to note is the before and after distortion performance of the DXT after applying a simple filter to flatten the response to get a "normal" flat response. Distortion at the point is much better than the current favorite Seas and RS28, not to mention the better off axis response and other advantages I noted above. I'm not sure how low this tweeter will be able to cross. IIRC, Seas recommends a 2k crossover point, but I'd imagine you could go a bit lower than that if using LR4 acoustic slopes. I'll know more when I run some tests.

Jed

[Jed]

I vote for DXT, W4 and RS270. Second choice would be DXT, W15, RS270.

BTW, why is the RS270 not used in any designs around here (apart from cjd's threeways)?

I brought the RS270 around the world so pleeeze I hope anyone build something with it! :B :rofl:

You looking for a new project Jonasz? I want to do a collaboration type project for the board again. Something that might take through the spring/summer to build. I wouldn't mind do something with an RS270 either. Everyone says they need large boxes, but I wonder how the bass would sound in 60L ported or 50L sealed? I've modeled it in unibox and it looks pretty good either way.

[---k---]

Everyone says they need large boxes, but I wonder how the bass would sound in 60L ported or 50L sealed?

This place is warped! Since when is 60L not BIG?

[Jonasz]

You looking for a new project Jonasz?

For the moment I don't have anything except veeery nice headphones to listen to. I'm thinking about a couple of dipole projects but they will unfortunately take some time to realize... A really nice fullrange threeway would be awesome to have in the meantime and later as a HT front-speaker. I do own a pair of RS270 and a pair of the titanium TB's. I also have a pair of W15CY's but they're currently used in my pc-speakers! :B

Would love a RS270, TB and DXT design! :P

[Brian Bunge]

Jed,

Maybe in a few months I could sell you 4 used RS270's for a good price!

No extra charge for the scientifically implemented "break-in" period.

[Jed]

This place is warped! Since when is 60L not BIG?

When you consider that the RS270s TS specs in Unibox, it suggests a 80-100L in a ported enclosure as optimum. I think I could get away with 60L with a bit more stuffing and a low port tuning.

[Silversmoky]

I like the sound of those projects Jed. I would probably opt for the dxt, w4, and dual 225's. Or dual Seas L22's? I haven't seen these used much and was just wondering how they match up against the 225's for a project like this. The 270 has always made me wonder too!

[Jed]

Would love a RS270, TB and DXT design! :P

It might be more appropriate to put the W4 in a computer speaker than the Seas W5CY, but then again I guess it depends on the design goals. Lately I've been playing around with a 3-way that uses 2nd order slopes and it definitely is smooth sounding.

[Jed]

I like the sound of those projects Jed. I would probably opt for the dxt, w4, and dual 225's. Or dual Seas L22's? I haven't seen these used much and was just wondering how they match up against the 225's for a project like this. The 270 has always made me wonder too!

I've heard the Seas L22 it it defintely has some very clean and tight bass. Just I guess the RS225 is the defending budget champ. It doesn't hurt that they are on sale right now either.

[Silversmoky]

Ya I saw that sale and was thinking about just picking up a few for whatever future projects might come along. I have always been impressed with them.
I always thought that the L22 would LOOK great matched up with a w4 just had never really heard any feedback about there performance. Your Lineup maxx tower design with the w4's and L16 always catches my eye!

[Dennis H]

BTW, why is the RS270 not used in any designs around here (apart from cjd's threeways)?

The RS270 looks sweet on an open baffle. I did a bit of modelling of pro 12" drivers on an OB thinking they'd be more efficient but they all start rolling off below 100 Hz or so and the 'real' efficiency of the RS270 is just about as good assuming you cross to a sub somewhere in the 50-80 Hz range and flatten the OB response with the crossover above there.

[Jonasz]

Lately I've been playing around with a 3-way that uses 2nd order slopes and it definitely is smooth sounding.

Do you think the RS270, TB, DXT combo would be able to make a 2nd order design?

[Jed]

Do you think the RS270, TB, DXT combo would be able to make a 2nd order design?

Yes, considering the W4-1337 is great fullrange, I bet it would work really well LR2 in the bandpass. The only concern I might have is how high the RS270 can go.

[augerpro]

BTW, why is the RS270 not used in any designs around here (apart from cjd's threeways)?

I brought the RS270 around the world so pleeeze I hope anyone build something with it! :B :rofl:

I have three projects rolling around right now but my primary one is a 5.1 setup using the RS270 and Peerless HDS 832873 and 810921 for the 3 way mains. The surrounds would be just the standard 832873/810921 TM and the center will be RS150/830872/D26 or 810921 WTMW.I had originally wanted to use the D26 all around but I like the 810921 too much. I haven't decided if I'll use teh D26 for all the speakers except the mains, or if I'll use the 810921 all around. I already have three D26's so I dunno...I was just waiting to finalize my Softy design using the 832873/810921 and I think I did that this week after listening to the third crossover revision. The basic idea is probably an active/passive hybrid by crossing the TM Softy to the RS270 around 200 Hz, with maybe some passive components for mild shaping. I'll be using the PE black curved enclosures all around, with the RS270 being bass bin style.

[Jed]

Sounds good Brandon. I just check out your tests of the RS270 and it looks really good. I think I could cross that as high as 400-600hz. Nice flat response and great sensitivity. Looks comparable to my Aurasound NS10s besides the Xmax limitation. I have a few questions though. What size enclosure are you going to use for the RS270 and why not go for a passive 3-way especially since you're going to cross around 200hz?

Jed

[augerpro]

Going active gives me a lot of flexibility regarding BSC and tonal balance. And I get rid of a big inductor. I have to do some modeling and measurements before I know exactly what I'll do. Many factors to balance...

I have no final box volume yet. Messing around the other day I think 75l tuned to 26Hz was well balanced, but nothing final yet.

So how is the SS 9800 treating you? You should post an update in your thread.

[Jonasz]

Yes, considering the W4-1337 is great fullrange, I bet it would work really well LR2 in the bandpass. The only concern I might have is how high the RS270 can go.

I remember JonMarsh saying it should be able to reach 600hz without problem!

[Jed]

So how is the SS 9800 treating you? You should post an update in your thread.

I'm using it LR2 with an Fc around 2.2k in my 3-way cabinet and I'm having some problems with diffraction causing a large-ish dip in the response around 2k, which then causes a problem with the phase alignment through the crossover region. Once I get some of these problems ironed out I'll post my results (new baffles and driver locations). Also, the C79 has been a pain to work with- it's the Diva of midranges. Parts count in my passive 3-way is up to something like 27 components.

[fjhuerta]

Sorry to bring the thread back on track , but - what do you guys think of this tweeter, then?

I like the idea of basically identical FR up to 30° off axis... that is something I'd like to try. But I'm a bit worried about the lack of very high frequency response. Can it be assumed that the real sensitivity of this tweeter is around 90 dB? Perhaps 88 dB?

My next project will definitely be a big WMTMW or MTMWW with a pair of RS225s, RS150s and the RS28s. If this tweeter can handle 2 KHz, I'd definitely use them instead of the 28s (as much as I *love* the 28s)... it looks great and the DXT documentation is very intriguing.

[Jed]

The seas DXT tweeter is speced out to 2k. Should be no problem at all. You could probably go much lower.

I'll let you know how it sounds this next week but I don't think anyone has actually listened to it with music yet.

Jed

[Jed]

Making a little bit of progress. Here is the DXT's distortion expressed as a percentage. I tested it in a 20L Madisound box.



Looks pretty much like John K.'s results in terms of non-linear distortion. I haven't tested the impedance or IB FR.

It's not bad for a non-ferrofluid tweeter but definitely not state of the art below 2k in terms of 3rd order harmonic distortion. I will take John's advise and try this tweeter with a 27 series ferrofluid motor. That should really improve the low end and allow a nice 1.5kish 4th order slope. I think Seas recommendation of a 2k Fc is spot on and this tweeter will perform really well in that regard.

Jed

[augerpro]

I'm confused. The DXT already has the 27 motor, just without ferrofluid correct?

[Jed]

I'm confused. The DXT already has the 27 motor, just without ferrofluid correct?

Correct, I bought a H1212 pair to swap motors with the DXT. I should have said a 27 series motor w/ ferrofluid (edited post above to reflect that fact).