Looking for a design using Seas P21RF/P 8" Poly

[LING GOWA]

Anyone know of a design which uses the Seas P21RF/P 8" Poly cone woofer with phase plug on sale at Mad? Looking for a 2-way.

http://www.madisound.com/catalog/product_info.php?products_id=834

I know that Mad has a design called the Cygnet: http://www.madisound.com/catalog/pro...roducts_id=379
What's with the tweeter on the bottom and both drivers off center?

[Notorious_AK]

I built speakers with these woofers
1.8mh inductor on woofer and 3.2 mfd cap on tweeter.
tweeter is Dayton ND28F. 8in sonotube from homedepot.
8in partsexpress waveguide. Dense polyfill staffing inside of tube.

[Amphiprion]

That's pretty cool AK.

[LING GOWA]

Wow Mark! That is incredibly cool but I'm looking for something more traditional. Thanks.

[b_force]

That's nice for a omnipole :P

How do you get the THD on a FRM with ARTA, or do you use the Spectrum Analyser ?

[eyekode]

Do you have some combined FR graphs?

[fjhuerta]

http://www.htguide.com/forum/showpost.php4?p=406882&postcount=53

[Undefinition]

I've been eyeing that woofer ever since Madisound put it on their sale page. I'd wager it's EXTREMELY easy to work with, because it has such a flat FR. Because it's a poly cone, it's not going to be as "detailed" as a metal cone driver. On the other hand, you could cross it with a bevy of tweeters somewhere around 2K and the crossover would be pretty simple.

Ling, I say get a reliable, bulletproof tweeter like the Vifa DX25 or Seas 27T_FC and try your own hands at it with a minimalist crossover. Tweak to taste!

[fjhuerta]

I've been eyeing that woofer ever since Madisound put it on their sale page. I'd wager it's EXTREMELY easy to work with, because it has such a flat FR. Because it's a poly cone, it's not going to be as "detailed" as a metal cone driver. On the other hand, you could cross it with a bevy of tweeters somewhere around 2K and the crossover would be pretty simple.

Ling, I say get a reliable, bulletproof tweeter like the Vifa DX25 or Seas 27T_FC and try your own hands at it with a minimalist crossover. Tweak to taste!

It's the easiest woofer I've ever worked with. I love it.

[djg]

Notorious AK, what are the details of your tweeter/ waveguide mount? Is the tweeter attached to the phase plug along with the waveguide?

Thanks.

[Notorious_AK]

Arta has harmonic distortion analyser. how to use it is explained in help file. it's not available through menu, shortcut is shift + f12
unfortunately I did not save combined graph. first graph depict woofer's response without inductor.

djg, phase plug is removed, tweeter (with it's wires going through pole piece hole) hot glued to small copper tube, which sits on top of pole piece.
I'll post detailed pictures later.
It's true, that's the easiest woofer to work with.

[djg]

AK, please do post some pics and construction details. This is a very cool design.

[LING GOWA]

I have a couple of Vifa DX25TG-05-04 tweets.

http://www.partsexpress.com/pe/showdetl.cfm?&Partnumber=264-578

[b_force]

Arta has harmonic distortion analyser. how to use it is explained in help file. it's not available through menu, shortcut is shift + f12
unfortunately I did not save combined graph. first graph depict woofer's response without inductor.

djg, phase plug is removed, tweeter (with it's wires going through pole piece hole) hot glued to small copper tube, which sits on top of pole piece.
I'll post detailed pictures later.
It's true, that's the easiest woofer to work with.

I didn't know the shift+f12 shortcut, thank you !!

Is there also an option where you get the Percentage of distortions ?

(i looked at the help file, but can't find the Shift+F12 shortcut)

[Undefinition]

I have a couple of Vifa DX25TG-05-04 tweets.
http://www.partsexpress.com/pe/showd...number=264-578

Well, there you go. A TM with that and the Seas 8" poly, and you're good to go!

[LING GOWA]

I know that Mad has a design called the Cygnet: http://www.madisound.com/catalog/pr...products_id=379
What's with the tweeter on the bottom and both drivers off center?

[Notorious_AK]

this is exploded view of tweeter/woofer assembly

http://img127.imageshack.us/img127/3046/img0462pz4.jpg

There must be a way to show distortion in percentage scale, I just prefer db scale.

[djg]

Thanks AK, how tall is the sonotube?

[Notorious_AK]

33 in

[djg]

Thanks.

[HareBrained]

What's with the tweeter on the bottom and both drivers off center?

Off center would be to have different baffle refraction on each side of the driver. If you play with Response Modeler, moving the driver off-center flattens the first peak. I've seen several D'Appolito MTM designs use off-center placement (with large round-overs) to great effect.

Tweeter on the bottom would imply the speakers were placed above the listening position. I doubt there's any tilt in the xo. It was probably to decouple the woofer and the port. Closer together, they might create a harmonic. Guessing only.