Boxing tweeters

[bigg]

I have noticed that some designs separate the tweeters from the rest of the cabinet with a piece of wood on the back of the front baffle while others call for a specific size of small box to attach right behind the tweeter.

I have closed off tweeters in some of the speakers I have built--with mixed results. :roll:

Is it that some tweeters should be boxed and others shouldn't?
How can you tell?

What is the benefit?

If boxing, how do you know what size box to use for the tweeter?

[JonMarsh]

Why do you say "mixed results"? There's no way I know of that blocking the cabinet pressure wave from the tweeter can deteriorate the results. Tweeters are sealed in the rear and if you close them off from the cabinet pressure wave, you only need enough space to accomodate the tweeter and wiring- it's not like a cone midrange.

[bigg]

Hi Jon,

I had some speakers that I blocked the back of the tweeters and they didn't sound good to me--sounded kind of harsh. But as you probably have guessed--I had other problems. I was using lead free solder for the first time and my solder joints were bad. It takes a lot more heat to get that tin based solder to flow well and I had apparently failed to do that. I found two solder connections that had broken loose and were only touching. Fixed that and now things are sounding good. Thanks for your reply. I still left the thread up to see if there were differnet ideas about the size of the box behind the tweeter. One other persons design (Wayne Jaeschke's Eros 2) I built called for a box 4"x 5"x 4". I think that's what it was. It's been a while since I built those.

[JonMarsh]

What was the tweeter? Conceivably, someone in the world makes a standard tweeter with an acoustic opening that requires shielding (if you take the back off of a Neo3 you're in that situation), but I've not heard of that for a conventional dome tweeter. When you couple plastic front plates with common rear chambers, my OCD tendencies kick in- if all it does is allow me to sleep better at night KNOWING that can't be an issue, then for me it's worth it. Others will disagree, of course. I don't personally do DIY to figure out how many corners I can cut- most commercial products have done that very well, thank you.

Yeah, bad solder joints can definitely queer things. If you go with ROHS solder, I recommend Cardas Tri-Eutectic and a good temperature controlled soldering iron. My Weller can go up to 850F, and can burn through the Litz insulation used on Cardas stranded conductors with a little patience. I still use Quad Eutectic though. Works and flows better.

[davey_m]

While using tweeters with a thin, plastic face plate eg the Seas 19TFF1 I did notice an improvement after isolating it from the woofer pressure. Treble sounded more fluid and natural. I don't no how much vibration couples into the dome movement, but there seems to be some.

[bigg]

The tweeter in the Eros 2s is a Scan Speak D2905/9500. I believe it has an aluminum face plate, not plastic. (Hey Jon-- Have you considered the Seas 27TFFNC/CG H1406 for the Modula Neo D? :roll: )

Protecting plastic faceplate tweeters from back pressure waves makes GREAT sense. :thanku:

I'm going back to the lead based silver solder now. My Weller works fine with the WBT stuff. :T