2-way journey with Seas W22EX

[Vikash]

I need some input and design ideas for my new project. So far the only things concrete are the midbass drivers, Seas W22EX001, and I'm aiming for a 2 way design (with sub work as an add on).

Things somewhat open for discussion: dipole, using clear acrylic baffle, active 8th order elliptical crossover between 1200-1500Hz.

There is a failrly tight budget. I've been/am quite resourceful and managed to get the W22 at a justifiable price thanks to ShinOBIWAN, and I have acrylic material with ability to machine it in abundance, and power amps are not a cost problem [chip amps]. However, I am a crossover newbie so this is one area I'll need a hand.

First question is which tweeter? The millenium is the obvious cost-no-object choice since many have already used this combo in OB configuration, but £300+ is way too much for tweeters at this point. Sub £100 to my door is more like it. Which leads me quickly to Zaph's preferences - 27TBFCG or 27TDFC (which I can't find in the UK?). Will any of these be suitable and go low enough? Any other suggestions?

[Mats J]

don't know what the cost would be for overseas shipping, but the Parts Express RS28 looks like a possible alterative.

site below shows favorable tests compared to SEAS units.

http://206.13.113.199/ncdiyaudio/mar...S28A/RS28A.htm

[Nuuk]

Vikash, wouldn't it be easier to go with active crossovers?

I was also looking for the Vifa D26NC55 (unsuccessfully).

[KevinTams]

Originally posted by Vikash

Which leads me quickly to Zaph's preferences - 27TBFCG or 27TDFC (which I can't find in the UK?).

https://secure.wilmslow-audio.co.uk/..._units_80.html
scroll down the page, the 27TBFCG is listed at £28 +V.

In my experience, (YMMV) without eq there is not enough bass to go down to a sub. Given that you need to xover to both a sub and a tweeter and IMO will have to put in some eq, then active is the way to go, unless you're prepared to put in the effort to design, tweak and test like mad.

Cheating and easy, is to go digital with a Behringer DCX2496. Find out what works with slopes, crossovers and eq, then build the discrete circuit if you don't like digital.

Kev

[Vikash]

Things somewhat open for discussion: dipole, using clear acrylic baffle, active 8th order elliptical crossover between 1200-1500Hz.

Can't get clearer than that

I was only referring to the availability of the 27TDFC

[AJinFLA]

Hi Vikash,

My only suggestion is that you iso-mount the W22 (bottom pic). An acrylic baffle is just fine if you use this method. I use a DCX for my 8th order elliptic filter (1.3k), WG loaded Vifa XT19. Since I don't know what tweeters are available to you its tough to make a recommendation. Good luck with your project.

Cheers,

AJ

[Vikash]

Hi AJ,

I've come across those pics before on the ht forum I think, but was gutted not to see a website link to your design Can you point me to where I can find more info/discussions about your design?

The XT19 is certainly cheap. I've read some mixed opinions regarding ring radiator dispersion, but any info/opinions will be appreciated

edit: how did you use that tweeter with such a low crossover Any measurements available?

[ShinOBIWAN]

Originally posted by Vikash
27TDFC (which I can't find in the UK?)

Originally posted by Nuuk
I was also looking for the Vifa D26NC55 (unsuccessfully).

Guys, ring Wilmslow up and they should be able to help. The Seas and Vifa range are pretty vast and not all models are listed on their website but if its a current model they'll be able to get them in for you and for a reasonable price as I found out when I ordered the shielded versions of the Vifa XT25 and PL17.

Originally posted by Vikash
Hi AJ,

I've come across those pics before on the ht forum I think, but was gutted not to see a website link to your design Can you point me to where I can find more info/discussions about your design?

The XT19 is certainly cheap. I've read some mixed opinions regarding ring radiator dispersion, but any info/opinions will be appreciated

edit: how did you use that tweeter with such a low crossover Any measurements available?

Good luck using the W22 in a 2-way

The breakup modes are quite ferocious on this one and slap bang at just above 2.5Khz. It should be doable but only with steep filters and some heavy duty notch filters.

Personally I'd go with the XT25 because I really love the sound of it for such a cheap driver, about 75% of the performance of the SS R2904-7000 that I also love to bits.

Now you've got the fancy software Really go to town and model some hypotheticals to see how the drivers interact along with polar plots for dispertion. With enclosureshop you've also got some powerful diffraction simulation algoritms so you can really fine tune your baffle size and driver locations, along with baffle step. Once you've got drivers that seem to work well together buy your chosen tweeter then build the test boxes/baffles, measure the drivers in situ and transfer that data into xovershop and begin modelling XO's. Then appy those findings and tweak out by ear and rerun measurements until your either happy or admit defeat

Decent modelling software takes a lot of the guess work out of this hobby and its quite incredible just how indepth and accurate it can be.

[lawbadman]

Hey AJinFLA,
How low do your speakers (the ones in post 6) go. The open baffle design looks interesting. The woofers look like they are Peerless subwoofers right?

[Vikash]

I've done a bit of modeling and these dipole response curves do not look appealing to work with. I've been seeing what a baffle roughly the size used in the Orion (12.5" x 18" at a guess) looks like in software, and it is certainly looks like a lot more work required than with a conventional box design.