Rythmik Sub Kit

[EricH]

I built a sealed DS15 kit from Rythmik. Great sub! Clean, accurate, very impressive on music as well as movies. I'm in the process of selling it to a friend to finance the purchase of two DS12 kits. They will be utilized as sealed bass bins for a pair of Adire DDR open baffle speakers. But for a single corner loaded sub, the 15 is almost impossible to beat for the price.

[darien87]

So this is my first Audio DIY project. Things were going pretty smoothly until last night. I plan on finishing up the
box tonight. So far, I have the bottom, 3 sides and
one of the braces in. I'll post pics when I get a chance. Last night, I installed Poly-fil and the sub. It was probably the most
frustrating thing I have ever done. I had one of the
holes for the bolts for the sub that ended up right
next to one of the braces. I checked with a bolt and
it was okay. But when I put the sub in, I guess it
shifted the position of the bolt a little, so I wasn't
able to put the nut on. So I took them all out again
and for some reason, that nut or bolt must have gotten
kind of stripped, because I literally spent about 1/2
hour just trying to get that one nut onto the bolt.
One of the other nuts must have gotten stripped also.
So now I have to go back to Home Depot to get 2 more
nuts and bolts. But when I bought them on Sunday, I
bought all 8 that they had. So now I have to hope
they got some more in.

Then, while trying to caulk the corners, I noticed
that I had put polyfil too close to the edges. So I
had to cut it to get into the corners. I'm still kind
of unsure how I'm going to caulk the top and back
panel after I put those on. I think I can put the top
on first and caulk the top. But once I put the back
panel on, it's going to be hard the reach inside the
amp hole and caulk the back panel. We'll see how it
goes. I think I will also try putting a thin bead of
caulk on the outside of the seams, just to be safe.

I'm telling you, with all this work, this sub better
be worth it.

[Ray Collins]

Welcome to DIY?!

Ray

[darien87]

Well, I got the box finished Tuesday night. I tried smearing caulking in all of the corners of the inside of the box. I did notice that there were some spots where it didn't look like the joints were butting all the way up against each other. So I was hoping that the caulking would help to seal the box. I even smeared a layer of caulking on the outside of the box to try to make sure it was sealed.

I tested it yesterday, and it was indeed hitting the low frequencies, it was easily doing 70db at 20hz. But when playing music or movies, the volume was maybe 1/2 that of my Earthquake MKIV 10 sub. I was pretty disappointed. I made sure to turn up the sub output on my receiver so that the Rythmik was putting out 70db with pink noise. But it was still very noticeably quieter than my other sub. I checked the corners, and it looks like the caulking actually shrank when it dried and the seams were no longer sealed. So, I put another couple of coats of caulking on all seams last night. I'll try listening to it again this evening.

My question is this: Was the fact that my box might not have been completely sealed, the reason for the lack of volume?

[EricH]

My Rythmik DS15 was quiet at first as well. Several hours of fairly loud music broke the driver in quite nicely, and I have been pleased ever since. It doesn't have the SPL of my old SVS PB12Plus/2, but the performance and sound quality is on another level. Concerning the cabinet, I would definitely get it as air tight as possible.

[Ray Collins]

darien87,
Even a small leak will have a significant impact on the performance. You may want to try an expanding glue like Gorilla Glue on the seams/joints. It can span cracks and fill as well as strengthen the joints.

Ray

[dswiston]

Also remember, the rythmik subs may have a much lower harmonic distortion than what you are used to. Quieter can often mean less second, third, fourth, etc harmonics that are not supposed to be there. To compound the fact, your ears are also much more sensitive to these higher order harmonics than say, 30Hz.

I realized how noticeable this can be while working on a servo controlled (accelerometer based) feedback sub project I worked on at school.

[darien87]

Originally posted by Ray Collins
darien87,
Even a small leak will have a significant impact on the performance. You may want to try an expanding glue like Gorilla Glue on the seams/joints. It can span cracks and fill as well as strengthen the joints.

Ray

Thanks for the info Ray. I ended up running out of wood screws while building the box, so I went to Home Depot to buy some more, but their selection was terrible. I ended up buying some screws that about 50% of the time ended up stripping or breaking. I plan to go buy some better screws to replace the crappy Home Depot ones. Guess I'll go buy some Gorilla Glue while I'm at it.

[Ray Collins]

darien87,
dswinston's point is very pertinent to what you are hearing.

If you buy a few clamps you can omit the screws. The clamps will pull the joints into close proximity and the gorilla Glue will do the rest. Both items are available at HD. I suggest the quick release type clamps...they accommodate one handed use and are moderately priced. If you need to stay with screws, I find that sheet rock screws, after drilling pilot holes, work well. After the glue bonds they can be removed...or not.

Ray

[darien87]

Originally posted by Ray Collins
darien87,
dswinston's point is very pertinent to what you are hearing.

If you buy a few clamps you can omit the screws. The clamps will pull the joints into close proximity and the gorilla Glue will do the rest. Both items are available at HD. I suggest the quick release type clamps...they accommodate one handed use and are moderately priced. If you need to stay with screws, I find that sheet rock screws, after drilling pilot holes, work well. After the glue bonds they can be removed...or not.

Ray

Thanks again Ray. Yeah, I used wood glue and clamps when I was putting the box together. I added the wood screws to just try and be absolutely sure the box was well constructed. Unfortunately some of the panels must have been slightly off, or I was putting them together slightly skewed, because I ended up with gaps in some places.

As for Winston's point: If the lack of distortion is also contributing to my lack of volume, do I just crank up the sub output on my receiver until I get the volume I want?