DIY Dayton Audio 18" Ultimax Sub Kit (UM18-22 and Denovo Flatpack)

[Medi0gre]

Looking forward to hearing your thoughts on these! How's progress coming?

 

[Sonnie Parker]

Having issues finding screws to screw them into the cabinet, of all things. Lowe's didn't have any... going to another hardware store today. I ordered some from Parts Express, but I am still not sure they will be what I need. The holes on the Ultimax are rather large... not sure what they were thinking.

 

[tesseract]

Would flat washers help, Sonnie?

 

[Sonnie Parker]

Probably so if I could find some the right size, and paint them black, which is my plan if I can't find screws to work.

 

[OJ Bartley]

Nice new subs, Sonnie! I'll be very interested in your impressions, after going through so many various sub types over the years. I hope these do the trick for you, at least until you order the 2nd pair.

 

[Sonnie Parker]

lol... yep, a second pair is definitely not out of reach... or want. Got some screws in today, so maybe it won't be long.

 

[Matthew J Poes]

Hey sonnie are they up and running now?

I have an idea I’m toying with that might be an option you want to consider as well. Basically it’s a DBA but with dissimilar subs. On the front wall you stack your eventual four 18’s such that they bisect the 1/3 wall points. Then you mount a set of low profile sub on the rear wall. Dayton has a low profile 10” and 12” that would work. These don’t need to play low or even all that loud. Small sealed boxes would be fine. These also need to bisect the 1/3 points. Then you power each set separately with an amplifier and use a dsp limiter to limit the rear sub at their spl limit (and delay to the length of the room). In practice this means you have the smoother where it matters up to fairly high spl levels, above say 100-110 db. Once the limiter kicks in the fronts would keep increasing but the reara wouldn’t so eventually there might be a noticeable shift in bass smoothness, but at frequencies and apl levels that don’t matter.

It’s obviously more expensive but I think it makes dBA benefits more realistic. I couldn’t have a wall of subs on the rear but I could have four small ones.

I’ve also modeled just one and just Two and found that deployed correctly, similar results can be achieved.

 

[Sonnie Parker]

They are up... connected, but not running just yet. I hope to integrate them tonight.

The problem with adding any additional subs right now is money... can't spend it right now. Maybe later on I will add a couple, but there won't be any room for any in the rear.

I've done something similar in the past with front and rear subs and it worked well, although positioning would be a lot more difficult to implement now that it was then with different rooms.

 

[Matthew J Poes]

They are up... connected, but not running just yet. I hope to integrate them tonight.

The problem with adding any additional subs right now is money... can't spend it right now. Maybe later on I will add a couple, but there won't be any room for any in the rear.

I've done something similar in the past with front and rear subs and it worked well, although positioning would be a lot more difficult to implement now that it was then with different rooms.

I should probably describe this in another post, but briefly I'll mention that my idea would be to build wall mount subwoofers that are no more than 4-6 inches thick. I think this would open possibilities for more people than past implementations.

I look forward to your impressions. I too am in a money crunch moment as I just completed my theater and easily spent 50% more than intended doing all the soundproofing and dealing with unexpected problems. None the less I have a single 18" ported box I have built and I am planning to order a driver for it soon.

 

[muzz]

DIYSG Flat packs are just stupid EZ to build, and Erics packing is ridiculously good.
How do you like the subs Sonnie?

 

[Matthew J Poes]

DIYSG Flat packs are just stupid EZ to build, and Erics packing is ridiculously good.
How do you like the subs Sonnie?

They are. He has made it hard to justify anything else. However it looks like he is moving more toward assembled boxes. I'm less interested in those because I don't normally order big pallet loads of stuff.

 

[muzz]

I'd be surprised if he totally abandoned flat packs in favor of assembled boxes, considering the difference in space it will take to house them, but I've been wrong B4.
I have Fusion 10's and Volt 6's here, and assembly was easier than Legos.

 

[loveg911]

What ever happened with the twin UM22-18 subwoofers? Specifically, what is their low-end extension? Do they go below 30hz?

I'm curious because I use a single UM22-15 in a 16ft transmission line and can only get down to about 25hz before I hit the excursion limit of the suspension at about 90dB. My goal is 16hz and am considering replacing the single UM22-15 with a pair of UM22-18's to get enough displacement.

So, if your UM22-18 won't do at least 20hz, this driver won't solve my problem. I suspect the Fs of the UM22-18 is too high for my application since I need the pair to have a combined resonance of 17hz.

Anyway, how do they sound? How low do they go?

Thanks,
GL

 

[Sonnie Parker]

They do very well.... sound excellent and extend on down below 20Hz with no issues. I should have a graph on my other computer that I will see if I can dig up.

Welcome to AV NIRVANA

 

[loveg911]

They do very well.... sound excellent and extend on down below 20Hz with no issues. I should have a graph on my other computer that I will see if I can dig up.

Welcome to AV NIRVANA

Sonnie, thanks for the reply.

Do you use or need EQ to get a flat response down to 20 hz and below? Or do you accept the natural slope fall off below resonance?

GL

 

[Sonnie Parker]

I have never known a sub that did not need at least some equalization... but I typically don't boost the very low end. It is mostly to smooth out the peaks.