Design Team Build: The Boomsticks - 2.5 way tower with 4 x RS100-8 and ND25F

[Navy Guy]

What did you use for the metallic looking feet atop the base?

These were aluminum discs cut by Kevin K. when he made the flatpack. I found some aluminum spacers on another website that I could have used if Kevin wasn't able to make them though.

http://www.fab-worxinc.com/stockchassis.html

[skatz]

I like that look, may have to try it!

[Kevin K.]

Looking good Kerry! How long do you have to wait to wet sand and polish or have you done that already, can't tell by that picture (pic looks grainy)?

[Navy Guy]

Looking good Kerry! How long do you have to wait to wet sand and polish or have you done that already, can't tell by that picture (pic looks grainy)?

Thanks, Kevin. They haven't been wet sanded or polished yet. I planned on waiting at least a week after the final coat of clear. I sprayed a whole can on this one but still don't think the clear is thick enough. Rather than spraying a ton of cans which will stink up my house forever, I just decided to by a can of clear enamel and roll it on and then try to polish it out after a few coats of that.

My phone camera has been really crappy lately. I don't know if it's going out or what, but it seems like it keeps getting worse. I didn't realize how grainy it was until I saw it on my computer. I need to get out the good camera to take a few shots.

[Navy Guy]

I had some time today to get things measured and play around with a crossover. I had all the parts on hand to build it so threw it together pretty quickly. Overall, a very simple crossover. Second order electrical with a bottomless notch on the woofer section (plus another inductor for second pair of woofers) and second order electrical on the tweeter. Here is the response at about 3 feet, 1/48 octave smoothing. Ignore the SPL level. It is not accurate.

[Navy Guy]

Nice weather this weekend so I got the other cabinet sprayed outside on Sunday without having to make a mess in my basement again. I also ordered all the crossover parts. Only had enough to test one cabinet so I haven't heard the pair together yet. One by itself has pretty deep bass but we'll see what it sounds like in stereo once the parts get in this week.

[Navy Guy]

So I've been testing these for the last week and a half or so. I started with the initial repsonse I posted and have made a few changed. A slightly larger inductor on the 0.5 woofer to bring the midrange down just a bit and some adjustments on the tweeter to slope the response downward a bit instead of the rising response you see in the measured graph. I think I have them about where I want them now and should be posting some more updates soon. Below is the modeled response using factory provided curves with the same crossover as what I had connected when I took the measurement. I'll provide updated sims with the new crossover later tongiht or tomorow and hopefully will have measurements within the next week or two.

. Tonight or tomorrow sometime I'll post the m

[joeybutts]

Exciting stuff here. Wish you were closer!!! What's ideal location in regards to wall placement? Thinking of maybe putting these in wall for my dad 😏😏😏

[Navy Guy]

Exciting stuff here. Wish you were closer!!! What's ideal location in regards to wall placement? Thinking of maybe putting these in wall for my dad 😏😏😏

I built these as a free standing design with full BSC. I could probably play around with the values to provide less BSC but I don't know how they would sound in-wall unless tested.

[Navy Guy]

So here is the intial modeled response with my measurements to compare to measured response


And this is the final modeled response with the crossover adjustments. I will be verifying with measurements soon.

[Navy Guy]

So I've got the final crossover settled on and took some final measurements today to confirm. Measurements taken at 30 inches with 1/48th octave smoothing and are SPL accurate. After listening to these for a few weeks now and making a few minor adjustments, I'm pretty happy with how they sound. These will be coming with me to InDIYana for anyone who is interested in hearing them.

[skatz]

In the end did you feel that the unevenness in the basecoat shows? I couldn't see it in the photos. I wonder if a sealer like shellac on the MDF would help that?

[Navy Guy]

In the end did you feel that the unevenness in the basecoat shows? I couldn't see it in the photos. I wonder if a sealer like shellac on the MDF would help that?

I used BIN 1-2-3 on the cabs, the filler primer. It's something to do with the way the paint sprays. The color coats weren't much better though, even though they have the better fan spray nozzle. It did turn out blotchy in the end. It's hard to see in some light, especially from a distance, but easy in others. I'll post some pictures later showing what I mean. Also, will probably have the crossover schematic and can dimensions up soon.

[Navy Guy]

I submitted all the info to the project showcase today and will post the writeup in the project gallery on the forum soon so it is easy to find all the info in one spot, but to wrap this up, here is the crossover and box diagram for these. The crossover was much simpler than I expected. I used a 0.1 uF and 0.22 uF capacitor in series to get the value I needed for the bottomless notch. A 0.1 uF was just a bit too large to hit the actual spot of the breakup. The notch probably wasn't necessary, but for $2, I'd prefer to just go ahead and use it. However, you can't remove it now because it does change the rolloff of the woofer if taken out. The crossover does dip to about 3.5 Ohms due to the small coil on the tweeter, but it is high in frequency and the phase angle isn't bad, so I don't think it will be a problem on any amp given the overall impedance everywhere else. I certainly didn't notice any issues on any of my amps I tested on.

[Navy Guy]

Write-up is in the project gallery now: http://projectgallery.parts-express....he-boomsticks/