Tuba folded horn HT subwoofer build

[Matt34]

Damage so far after about 13 hours of work from the last two days.

All the panels cut:

Measurements for access panel and the panels that will actually make up the horn:

Access Panel cut, getting the counter sunk screws ready:

Panels one and two in place:

Hole for the sub in Panel three:

Panel 3 in screwed and glued:

Panel 5, aka "the PITA":

We have five more panels to install and 7 more braces to fab and set. Should have it together tomorrow, the Dayton sub probably won't be here until mid week.

I think I'm going to keep the finish simple and do a black stain.

 

[STRONGBADF1]

Very cool, Matt! Keep the pictures coming!

 

[Matt34]

Very cool, Matt! Keep the pictures coming!

Thanks, I will....it's been a learning experience to say the least.

 

[TLS Guy]

Damage so far after about 13 hours of work from the last two days.

All the panels cut:

Measurements for access panel and the panels that will actually make up the horn:

Access Panel cut, getting the counter sunk screws ready:

Panels one and two in place:

Hole for the sub in Panel three:

Panel 3 in screwed and glued:

Panel 5, aka "the PITA":

We have five more panels to install and 7 more braces to fab and set. Should have it together tomorrow, the Dayton sub probably won't be here until mid week.

I think I'm going to keep the finish simple and do a black stain.

Nice work. I would not stain the plywood black. That does not look good at all. It will not be much extra work to cut some 1/4 oak veneered plywood and fastening it with impact adhesive. Then you can do a really nice wood finish. That is a big box and dark stains will make it look bigger.

 

[WmAx]

He won't get close to exceeding xmax. If he gets close to xmax he won't have a house. In a decent horn the driver uses very little of its displacement.

Most drivers have poor motor linearity, even at 1/3 to 1/2 rated x-max, and the suspensions are usually poor in linearity as well. The RS driver mentioned has extremely linear motor performance; it's motor strength and other characteristics are nearly identical from rest to full rated x-max.

A horn is an acoustic transformer, and the output will nearly all be from the mouth of the horn. It is big and will really couple to the room.

It is no 'secret' that it will have high output. As I stated previously, the horn will have at least 3x the output within it's effective bandwidth, as compared to a standard cabinet. But it's no free lunch. A HUGE cabinet is required for a single driver to achieve an extended bass response in a horn type cabinet. One can get more output in a much smaller total space using more drivers with high power. The horn is much more economical if the space needed is available, of course.

-Chris

 

[Matt34]

Wow PE is fast! Even with the free shipping option.

 

[Matt34]

I'm getting a little ahead of myself but thinking ahead with the veneer option, would it be better to leave the edges and corners as is or can I still run a round-over bit?

 

[Swerd]

I'm getting a little ahead of myself but thinking ahead with the veneer option, would it be better to leave the edges and corners as is or can I still run a round-over bit?

Nice work so far. That folded horn is interesting.

I've rounded over MDF, but I'm not sure what happens with plywood. You can always practice with some scrap pieces. You might be better off if you glue a hardwood strip on the edges and round it over instead of the plywood.

What size roundover bit are you going to use? ½" radius works OK with a hand held router, but ¾" is another story. Do it very carefully in several passes.

Depending on the type of veneer, applying it over a rounded edge, even if the grain is parallel to the edge, can crack the veneer. Again, practice with scrap pieces.

You do realize that this is for looks only? A rounded edge on a subwoofer has no acoustic function like on the baffle edges of a full-range speaker.

 

[Matt34]

I've rounded over MDF, but I'm not sure what happens with plywood. You can always practice with some scrap pieces. You might be better off if you glue a hardwood strip on the edges and round it over instead of the plywood.

What size roundover bit are you going to use? ½" radius works OK with a hand held router, but ¾" is another story. Do it very carefully in several passes.

Depending on the type of veneer, applying it over a rounded edge, even if the grain is parallel to the edge, can crack the veneer. Again, practice with scrap pieces.

You do realize that this is for looks only? A rounded edge on a subwoofer has no acoustic function like on the baffle edges of a full-range speaker.

I've seen others that have used a round over bit on plywood, I don't foresee a problem there.

1/2" may be what I use if the veneer is capable. Yes, I realize it's purely for looks and somewhat of a safety measure....fresh-walking toddlers and sharp corners don't mix.

 

[ParadigmDawg]

Man that just stinks....I can't believe that they punctured your woofer with that crappy remote

Wow PE is fast! Even with the free shipping option.

 

[Matt34]

We burnt the midnight oil and got it to a functioning state, still have to finish up some odds and ends i.e. access panel frame and cut the hole for the speaker wire terminals. Because we followed the rule "measure twice, cut once"(ok more like five measurements), prepping and sanding won't be as long and tedious. Now I need to decide on a veneer and stain.

I'm too tired to write comments on the pics so I'll let them speak for themselves:

 

[Matt34]

 

[Matt34]

 

[ParadigmDawg]

Awesome build.

How big is that thing?

 

[Matt34]

Awesome build.

How big is that thing?

Thanks, 36x36x24 1/2

 

[annunaki]

Thanks, 36x36x24 1/2

Where are the braces? That thing is MASSIVE!

 

[adk highlander]

Wow Matt that thing is HUGE!

Thats for all the great pics of the build. I'm looking forward to hear what you think once it is up and running.

 

[ParadigmDawg]

I hear that all the time....

that thing is HUGE!

 

[Matt34]

Where are the braces? That thing is MASSIVE!

I made a command decsison and left them out, they weren't in the orginal plans and with the way this thing is put together I could jump on it and it wouldn't budge. I will put two braces in the mouth of the horn but we both felt that the other vertical braces were complete overkill. It's easily over one-hundred awkward pounds as is.

 

[sawzalot]

That is a very impressive build Matt, that thing is really of some size, excellent work putting together what looks like a maze of passages really cool.I can't wait to hear your thoughts on the performance when complete and thanks for the great pics.