W5-704 + ND20 can work together well?

[critofur]

Tang Band W5-704:
http://www.partsexpress.com/pe/pshow...number=275-035

and

Parts Express "Dayton" ND20F: (the new model)
http://www.partsexpress.com/pe/pshow...number=264-850

Anybody made crossovers for this pair?

How would you cross them and why would you choose to do it that way?

[dlneubec]

I have not used these two together, but do have a project that is underway using the W5-704 and the Dayton ND28F, the big brother to the ND20. Here is a photo of the project and a link to a thread on it over at HTGuide. The W5-704 can be crossed pretty high, so I could see the ND20 working. In my case, the ND28F is rear mounted in a 1/2" wavegide like Zaph suggests for the Vifa D26ND55.



The Duo's

[critofur]

Ah, yes, I had been looking at your designs on HTguide.

The ND20 is sooo cheap, and looking at the FR chart on Zaph's site the latest version's response looks so nice:


The ND28 response looks fairly bumpy, no?:
http://partsexpress.com/pdf/ND28F-6_specsheet.pdf

I was thinking that the W5-704 is a little too large to be crossing it at ~3Khz or higher (poor [narrow] dispersion) and also the top end maybe a little rough? (though not nearly as nasty as metal cones...)

With the ND28 it prob. can cross just low enough to pair well with the W5-704 without having to go sharper than 2nd order slopes?

It's looking more and more to me like I can't get a very good design w/1st order slopes without using some kind of 2-3" upper midrange in between the tweeter and midrange.

I've got a bunch (about 15 or 20 or so) of Audax TM20J8 3/4" Neo soft dome tweeters which have a fairly similar response to the Dayton ND20s, that's one other reason I had an interest in them [ND20], I figured a design with one could easily be tweaked to work with the other.

[EDIT] Oh, and I wanted to participate in the discussion over on your HTGuide "Duo" thread, but, one of the more veteran members and a mod over there were real jerks, ended up getting me banned from posting even though we had moved our discussion to PMs!

[EDIT#2] I had been thinking of doing something like that w/the tweeter, but with a 3/4 roundover - I'd like to see how the two compare (3/4 vs 1/2). But what I'd really like to see is, if you use a 1" roundover except on a 3/4" thick board so that you'd be using the "top" 3/4 of the roundover resulting in a slightly shallower [slope] and broader waveguide.

How about a design like this for your tweeter housing above the woofer?:

[critofur]

Here's what I mean by using the "top" 3/4" of the 1" roundover.

I guess I would do it by temp. attaching a 1/4" "backer" board to the 3/4" material that we'd use for the front board/corian/etc.

I was thinking of this idea because most of us can't afford CNC machines and working with pre-made plastic wave guides is a bit of a pain, and the idea of using the wood baffle as the wave guide has been intriguing for a while...

I wonder if this method could also be used with the Dayton RS52? Has anyone taken the face plate off and know if it could be rear mounted on a baffle this way?

[critofur]

Hmm, how about this router bit for making wave guides?:

I don't know enough about wave guide angles, maybe the slanted portion is too steep and the beginning of the throat will be too much like a pipe?


[EDIT](I would make a template backer board and use the bit on 3/4", or, possibly, 1" thick (cut in two 1/2" steps, using two templates) baffles.

Maybe I should have made a new thread about cutting wave guides on baffles, instead of tacking on this one?

[augerpro]

I've just started using the W5-704 and I'm happy with it so far-considering the low price. It can do 2nd order, but just barely and it should really be crossed fairly low to keep the grunge around 4k Hz from causing problems. I'm crossing LR2 @2.5k Hz to a Vifa DX25 and almost nailed the crossover right off the bat. The preliminary version sounds very good, just had to drop the tweeter level a bit. The woofer itself does an amazing thing you don't find at this price often- it doesn't do anything annoying. Not the bottom line in clarity of course, but it doesn't do anything to really screw up the sound either, just matches the DX25 quite seamlessly.

[critofur]

Also remarkable, is that most expensive woofers do do annoying things, in one area or another. What interested me in the W5-704 in the first place was the combination of low price + lack of giant spikes of cone resonances on the top end.

Now, if we find some modifications we can make to the top end of the W5 smoother such as: removing the dust cap and putting a phase plug, "glue mods", embossing the cone, etc... maybe we can make the crossover even nicer?

Hmm, I wish I knew how MarkMCK did his cone breakup analysis, so I could have some idea how to figure out exactly where to, say, cut slits in the cone then use thin strips of that thin aluminum heating duct tape to seal them...

You said you had to drop the tweeter level a bit with the Vifa X25, do you think if you used a pair of W5's their level would match the tweeter without having to do any R padding?

I wanted to reply in your thread also, over on HTguide - I guess I'll have to make a new account over there since I don't have any un-ban hax.

[Moondog55]

Hi Critofur, I know very little about wave guides, only what I have gleaned from the forums.
I know that in his "Tweeter mish mash" JK has a small article on the Vifa neo tweeter and he use's ( from memory ) a 1/2 inch roundover.
Maybe this deserves a thread all of its own??

My thinking was that a bigger driver might need a different profile, flared starting steep and then getting shallower but all I can find in router catalogues are Roman ogees and roundover bits.
My thinking and it is probably a little naive, is that a biggish round over would allow a smallish woofer ( 6 to 10 inches ) to couple just a little better to the air and be a little more efficient.

Is the reason it's not done the paucity of suitable router bits??
As stated in the other thread the bits would have to be great big ones and then you have all the associated costs of big high horsepower routers.
Good question , needs serious discussion,
Regards Ted

[critofur]

Here's the bit from the picture in my earlier post, I meant to add the link, but my time to edit expired...

http://www.amazon.com/Freud-85-001-2...813120&sr=1-20

[Moondog55]

That looks like it should work, I have seen nothing like that here in Australia, would need a big router to drive it though, so smaalllll bites of the cherry, I used a 1/2 inch round over on my 10 inch woofer but project not finished yet so no SQ test done