The SideTowers - An F6 Corundum Build

[4thtry]

Greetings to all,

This will be my entry for InDIYana 2019. I'm calling them "The SideTowers," as I built them to be tower type speakers in the sideways direction. This resulted in a very small front baffle surface area, which I then softened with multiple facets. As a bonus, this configuration gives me a little extra distance between the woofer and the internal rear wall reflection.

Specs: Drivers: HiVi F6 & Peerless DA25 (corundum dome). Fb: 36Hz F3/6/10: 32/30/28.
Xover: 1.3kHz; 5 parts. BSC: 6dB. Gross Internal volume: 1.18 cu ft. Weight: 37 lbs.


This will be a ML-TL, so I modeled the line in 4 sections using the LA TL program. Without stuffing, the optimal position for the woofer was 4.5" down the line. I was going to place a small partition near the front of the line to create this 4.5" trap, but later on discovered that this was not needed. Simply stuffing the first 8 inches with 5.5 ounces of denim flattened out the 1st and 2nd line peaks considerably. And this 5.5 ounces only caused a loss at the main port resonance (Fb) of about 1dB.

[4thtry]

I installed a slot type port at the rear of the cabinet, constructed out of 3/4" laminated particle board. It is 8.3 inches long and measures 1 x 6.5" internally. (see pics)

I put two crisscross type braces along the length of the line, rounding the edges for improved air flow. (see pics)

The 3/4" particle board shelving material that I used was laminated on both sides, so, as you can see in the pics, I pre-sanded the laminated gluing surfaces with #40 grit for improved adhesion.

[4thtry]

Here are a few glue up and baffle machining pics. I scalloped the internal F6 woofer hole for improved air flow and reduced near field reflections. The tweeter is flush mounted with a 1/16" recess. The woofer is surface mounted so that it can partially overlap the tweeter flange.

[4thtry]

I drilled a couple of 1/4" holes and brought a pair of 16ga OFC wires out the back for the woofer and tweeter connections. I sealed the holes on each side with silicone rubber cement. I pasted these wires internally on alternate sides of the box using double sided carpet tape.

The back 2/3rds of the box is open in the center and lined with 1/2" rigid fiberglass panels. No fiberglass is placed near the slot port opening. I rounded the port entrance and exit edges with a 1/2" round over bit.

[4thtry]

I lined the 8 inch area directly behind the woofer with 1/4" thick denim insulation. (Later on, I completely stuffed this 8 inch area with 5.5 ounces of denim batts.)

In preparation for gluing the top panel in place, I cut notches in two spacer boards for two long bar clamps and then placed the top panel on top of these spacers and clamps. I lined the top panel with 1/4" denim and then applied yellow glue to all the mating surfaces. Next I placed the box shell onto the top panel and let the yellow glue slowly meld into the particle board mating surfaces. I was careful not to let the glue squeeze out too quickly, as I wanted to give it a little time to soak into the wood. After a couple minutes, I checked the alignment and tightened all clamps up to a moderate pressure.

[4thtry]

I mounted the drivers and installed the xovers on a small board on the rear of the cabinets. As mentioned previously, the tweeter flange goes underneath the woofer flange, overlapping by approximately one inch. This reduces the center to center distance from 6.5 to 5.5 inches, thus helping to improve the vertical polar response pattern.

Right now I am debating as to whether or not I should finish and paint the exposed particle board edges and facets or do something else. Maybe I should line the entire baffle & faceted edges with a large piece of peel & slick felt material. Then cut a small hole in the felt just large enough to expose the corundum tweeter dome!

[4thtry]

That is all I have time for today. I plan to run up a complete set of measurements with OmniMic and DATS V2 and will try to post these in the next few days.

[Wolf]

You aren't wasting any time are you?
Wolf

[donradick]

Greetings to all,

This will be my entry for InDIYana 2019. I'm calling them "The SideTowers," .......


This will be a ML-TL, so I modeled the line in 4 sections using the LA TL program. Without stuffing, the optimal position for the woofer was 4.5" down the line. I was going to place a small partition near the front of the line to create this 4.5" trap, but later on discovered that this was not needed. Simply stuffing the first 8 inches with 5.5 ounces of denim flattened out the 1st and 2nd line peaks considerably. And this 5.5 ounces only caused a loss at the main port resonance (Fb) of about 1dB.

Inspiring design and build as usual!
I've spent some hours in HornResp, but certainly I'm not an accomplished ML-TL modeler.
What's that "LA TL" program? Got a link?

[wogg]

Awesome! Where to find a 3 foot deep bookshelf for those things? ;)

[Wolf]

I think Bill is mandating room position, as you can't place them any closer to the front wall of the room.

However, I wonder what they would sound like and how they would perform in an upfiring Omni situ like Duevel's Planets.

Later,
Wolf

[humphreyblowdart]

What's that "LA TL" program? Got a link?

I think he means Leonard Audio. This thread has some details.

[wogg]

I think Bill is mandating room position, as you can't place them any closer to the front wall of the room.

However, I wonder what they would sound like and how they would perform in an upfiring Omni situ like Duevel's Planets.

Later,
Wolf

Plus you still get some boundary low end reinforcement from the rear port! That might be genius.

Bill 4thtry , you seem to be on a mission to minimize your baffles with your totally flat and this project. At some point I see you magically fabricating a single theoretical point source

[donradick]

I think he means Leonard Audio. This thread has some details.

Thanks buddy. Tried to install LATL a couple of months ago, and failed. I'll give it another try.

[carlthess40]

Where would you place these and how do they sound? Is it more of a rear or side speakers for a HT setup or a 2.0 setup and have them on with sides of the main wall? Very cool build with a lot of questions