Yet Another Table Tuba Build

[Dougbert]

Hello,

I did this build last December, and I have finally gotten a chance to upload all the photos.
I built it essentially according to the plans: 1/2" BB plywood and the recommended driver.
I happened to have a brad nailer (a fairly basic one from Harbor Freight), and it was very handy.

BTW, I had no trouble cutting all the pieces from two 5x5 sheets of plywood, thanks to the "cutlist" software.

[Dougbert]

More photos, as the assembly begins.

The cutting table was really handy!

[Dougbert]

The assembly continues.

I misunderstood the part in the plans abut mounting the driver. I didn't realize
that I should use wood screws, threaded directly into the wood. I did make
sure that the T-nuts were securely glued into place.

[Dougbert]

Around and around I go...

[Dougbert]

At the beginning of the assembly, I forgot to mark up the top panel with the locations of the inner pieces.
But I thought up an even better way: I placed a large piece of tracing paper over the edges of the panels,
and marked their positions. Then I placed the tracing paper over the top panel and shot brads right through the paper.

[Dougbert]

Final assembly and finishing: I used Minwax transparent stain, sanding sealer, and water-based polyurethane
simply because I had them lying around. Also, I wanted it to match the birch Ikea cabinets in my basement...

[Dougbert]

I sort of wish I had used a 10" driver... The additional cost would have been small compared to the time I spent.
But it is plenty loud enough with the MCM 55-2421 driver that I used.

I added a couple of handles- otherwise there was no way I could have gotten it down the basement stairs.
Most of the nicer-looking drawer pulls required mounting screws from behind, and obviously that would not work.
But I found these in Home Depot, and they sort of matched the other furniture.

Anyway, that's all. It has been part of my HT system since the beginning of the year,
along with a Onkyo TX-NR636 receiver, Onkyo speakers, and a Yung SD100 100 watt plate amp.
(I do wish I had gotten a more powerful place amp, though. The actual impedance of the speaker
is more than 4 ohms, so I don't get the full 100 watts.).

[Chris_Allen]

Lovely finish. I've used wax oil to get a similar finish on a desk.

[johns811]

How does it work without the chamber opening closed? Is that a piece of clear plexiglass or something.

[Grant Bunter]

How does it work without the chamber opening closed? Is that a piece of clear plexiglass or something.

As for the lack of a cover over the access, most bass horns seal the rear chamber to tune the cabinet response and apply restorative force to limit the excursion of the driver. The Table Tuba horn is long enough so that the air mass of the horn alone will tune the driver response and limit excursion. Excursion above 15Hz is unaffected by the lack of a cover. Moreover, the open chamber is a second sound source at very low frequencies, similar to the port of a bass reflex cab. To preserve the tuning of the cabinet the side with the access hole should be 1½ to 2 inches away from the boundary, be it a wall or floor. If you lay the cab on the floor use legs to lift it 1½ to 2 inches.

[Bill Fitzmaurice]

How does it work without the chamber opening closed? Is that a piece of clear plexiglass or something.

As for the lack of a cover over the access, most bass horns seal the rear chamber to tune the cabinet response and apply restorative force to limit the excursion of the driver. The Table Tuba horn is long enough so that the air mass of the horn alone will tune the driver response and limit excursion. Excursion above 15Hz is unaffected by the lack of a cover. Moreover, the open chamber is a second sound source at very low frequencies, similar to the port of a bass reflex cab. To preserve the tuning of the cabinet the side with the access hole should be 1½ to 2 inches away from the boundary, be it a wall or floor. If you lay the cab on the floor use legs to lift it 1½ to 2 inches.

Or you could have just said "It's in the plans".

[Grant Bunter]

How does it work without the chamber opening closed? Is that a piece of clear plexiglass or something.

As for the lack of a cover over the access, most bass horns seal the rear chamber to tune the cabinet response and apply restorative force to limit the excursion of the driver. The Table Tuba horn is long enough so that the air mass of the horn alone will tune the driver response and limit excursion. Excursion above 15Hz is unaffected by the lack of a cover. Moreover, the open chamber is a second sound source at very low frequencies, similar to the port of a bass reflex cab. To preserve the tuning of the cabinet the side with the access hole should be 1½ to 2 inches away from the boundary, be it a wall or floor. If you lay the cab on the floor use legs to lift it 1½ to 2 inches.

Or you could have just said "It's in the plans".

Ohhhh err yes I could have said that.
When answering it occurred to me that if Johns811 had the plans he wouldn't have asked the question.
Every now and again I try to be nice to people lol.

Speaking of which;
Dougbert,
Very nice clean build and finish.
Hope you're enjoying it

[bassmonster]

Nice build. What's that antique I see in the background of some of the photos? Ford Model A?

[jimbo7]

Nice build. What's that antique I see in the background of some of the photos? Ford Model A?

looks like a model a engine to me

[johns811]

How does it work without the chamber opening closed? Is that a piece of clear plexiglass or something.

As for the lack of a cover over the access, most bass horns seal the rear chamber to tune the cabinet response and apply restorative force to limit the excursion of the driver. The Table Tuba horn is long enough so that the air mass of the horn alone will tune the driver response and limit excursion. Excursion above 15Hz is unaffected by the lack of a cover. Moreover, the open chamber is a second sound source at very low frequencies, similar to the port of a bass reflex cab. To preserve the tuning of the cabinet the side with the access hole should be 1½ to 2 inches away from the boundary, be it a wall or floor. If you lay the cab on the floor use legs to lift it 1½ to 2 inches.

Thanks, I only built the T24 and a cover was mandatory. It thought they all needed covers.