BillFitzmaurice.info

After years of not having a subwoofer in my basic home stereo setup, I decided that the time had come. I started over on the AVS Forum and kept seeing mention of the THT (which was way too big, but intriguing). After some snooping around, I landed on this site and found the Tuba 18, which seemed like the best fit for my living room.

I ordered the supplies, including the Dayton DCS205-4 and the Dayton 100W plate amp. I went with the Dayton sub over the MCM because most of the supplies I needed were from Parts Express and the price would have been about the same after shipping if I ordered from both places.

My trip to Lowes was disappointing as they didn't seem to have any good plywood. I headed over to Menards and found arauco plywood for $20/sheet for 4x8. I really wanted Baltic Birch, but they only had it in 1/4" thickness.

On with the build... Most of the pictures were taken with my phone, so I apologize for the quality:

Started out by ripping all of the 17" wide pieces:


Doing some drawing. I wanted my access panel on the opposite side due to the corner that it will be placed in, so I reversed the plans.:


So, my sled was covering up the lines and I didn't think to mark my stop point ahead of time.


I was getting pretty good at drawing these lines the second time around.


Bring out the PL:


Made a little router jig to cut out the hole:


T-Nuts in with epoxy. Someone mixed the wrong size in at the hardware store, so I had to go back the next day to get another one.








Mistake number 2. This wasn't a case of measure twice, cut once. It was a case of check the plans twice, cut once.


More progress:


The end is in sight:


Looks like a conch shell:


Speaker terminal in:


Other side:


Time for the last panel:


I used screws to hold the panel on, but I figured a little extra weight couldn't hurt anything:


Driver mounted:


Gasket tape installed:


Access panel:


Test run:


The plan is to turn this into an end table to blend into the room. Last night, I put a birch veneer on the outside and I'm planning on 3" boards for trim to finish it off.

I'm hoping to be done with it sometime next week, so I'll post more pictures when it's done.

My impressions: Considering the size of the driver and enclosure, I'm really pleased so far and it has handled just about everything I've thrown at it. Would it be dominated by a THT? Of course, but for the levels that I usually listen to movies and music at, it sounds great. The only problem I have now is to fix all of the rattles in my house.

My house is a fairly open layout where the living room, dining room, and kitchen are open to each other, so I'm sure it's not as loud as it would be in a smaller room. Initially, I was running a full signal without a high-pass filter set and I could tell that it was reaching the limits on certain movies like Transformers 2 with the volume cranked. My receiver is old enough that it doesn't have high or low pass filters for the sub out, so I used an extra Behringer EQ to set a high pass filter around 35hz and haven't run into any "pushing the limits" issues. I'm still experimenting with the low pass filter, but it seems to work well around 60hz (hard to tell exactly what it's set to on the Dayton amp though).

When my tax return comes in, I'm going to step into the 21st century and replace my old trusty Kenwood receiver with something more modern.

Nice build!
Just for learning, run Transformersagain and use the volt meter to see what kind of voltage you're pushing.

Tom Smit wrote:Nice build!
Just for learning, run Transformersagain and use the volt meter to see what kind of voltage you're pushing.

I'll try that this weekend. Do you have a suggestion on the voltage limit?

25 volts

Good work!

Tom Smit wrote:25 volts

Thanks!

loudsubz wrote:Good work!

Thanks, I'm anxious to get it finished up this weekend.

Shawn, How did you do the rounded edges on the access panel? I imagine I would do it by making a jig, but that's time consuming- do you have a trick?

djtecthreat wrote:Shawn, How did you do the rounded edges on the access panel? I imagine I would do it by making a jig, but that's time consuming- do you have a trick?

I used a rabbet bit on my router for the opening on the cabinet itself. As far as the curves on the panel, I just marked the lines with a pencil and used my router table to cut the curve out by hand. I'm sure there's a more scientific way to do it, but I wasn't overly concerned since the access panel side will always be against a wall.

Shawn, that T18 is looking VERY good! It is great to see a T18 build come together. Looks like a miniature TT (or THT as the case may be!).

Any ideas on how you are going to finish it?

NCDaveD

Tom Smit wrote:25 volts

Try 20v. Remember it is a 4ohm driver and 125watts rms. At around 18-22volts it will start complaining, any higher than that it you're just abusing it.

Although out of everything i've built, the t18 might be my favorite, you will definitely want to build yourself a table tuba. Even my 13" TT downright better for movies and the deep bass music. Even for some songs, my t18 would drop the ball in some of the low end material, and if you really want to feel movies, this is where the beef is at.

Looks like fine quality birch ply. With all edges routered round-over and PU clear-coat it would look very nice. That's how I did my T18, still like it.

NCDaveD wrote:Shawn, that T18 is looking VERY good! It is great to see a T18 build come together. Looks like a miniature TT (or THT as the case may be!).

Any ideas on how you are going to finish it?

NCDaveD

Here's what it looks like right now:


I've got a solid 3/4" wood top to go on there that still needs stained. I'll finish the whole thing in a satin polyurethane and call it done.

Uh... WOW. That looks great Shawn. Nice work brother!

That looks great!

Amen!