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Decided on building quad Sealed subs. LOTS of questions.

723 Views 14 Replies 8 Participants Last post by Trimlock, Oct 14, 2019

ratm

Discussion Starter · Oct 13, 2019 (Edited)

Hey everyone,

After reading countless threads about ported vs sealed, I have decided to sell my JTR Cap 2400 and go the sealed DIY route. Specifically quads (2 now and then 2 soon after). A couple reasons for this. First, I almost never ever listen to reference level volumes (I've never come close to pushing the JTR to its limits). So max SPL is not my end game. Second, I have a small - medium(ish) room. My living room/dining room is an open concept, but my listening area is about 15 x 25 and rectangularly shaped. From my main LP, the left sub would be in a corner (1/2 wall is only 3 feet) while the right would be about 3 feet from its wall. The subs I will eventually build for near field will both be corner loaded and about 3-4 feet behind where I sit. These will be for 90-95% TV and Movie usage with the rest music. My absolute max budget when all 4 is done is $2k.

Some random thoughts/questions...

- I was planning on using a iNuke 6000dsp as my amp each of the 2 amps. I like the DSP aspect and it seems cost effective.
- I really like the completed dual box from DIY Sound group. Would two of these, one in front and one behind my main LP be a good option as opposed to 4 cabs?
- I really like the flat pack aspect. I built my LCR from DIYSG flat packs and love them.
- I initially was set on the UM 18-22 but then came across the HST-18 and UXL-18, both of which are substantially more in cost than the Dayton. As I said, I dont need crazy SPL, but also don't mind spending the money for the latter if they will make that much a bigger impact.
- With respect to cabinets. Are their cabs specifically designed for each of the drivers I've listed?

Ugh, so much information. But thank you to anyone who takes the time to help me out.

1 - 15 of 15 Posts

Chris Popovich

· #2 · Oct 13, 2019

The JTR is a well reviewed/liked solution, but I understand the DIY appeal for sure.

4 cabs gives you more placement flexibility and better individual eq control, but 2 can still be respectable. If you're used to just one sub now, and was able to integrate it successfully, then two will definitely work just fine.

Sealed is a lot more flexible and tolerant to design tweaks. 4cuft per driver works reasonably well for a variety of 18" drivers on the market. UM18-22's are great drivers, with 4 of whatever you choose you're going to be happy, just take your time with integration.

Ex JL Rep

· #3 · Oct 13, 2019 (Edited)

some thoughts:

Different drivers will require different amounts of air space / box size. Since you want sealed, I would just plug in the specs to an online speaker enclosure calculator to determine box size for a given driver. As a starting point, I would put in a System Q (Qtc) of .88 to find a minimum box size for good sound. You can go a little larger on box size if you find a flat-pack you like.

- I really like the completed dual box from DIY Sound group. Would two of these, one in front and one behind my main LP be a good option as opposed to 4 cabs?

- well, some recommend 3 or more subs throughout the room to deal with standing waves.

- I would try the sub you have near-field to see how it sounds. It's free to try!

- I initially was set on the UM 18-22 but then came across the HST-18 and UXL-18, both of which are substantially more in cost than the Dayton. As I said, I dont need crazy SPL, but also don't mind spending the money for the latter if they will make that much a bigger impact.

- well, I looked up the HST-18 and it has a lot of throw, more than the Ultimax. Headroom is good. However, some claim distortion can rise with throw (xmax). There are always compromises, no free lunch. Plus you said you don't need a lot of output? The Ultimax is a lot of sub for the money... it looks like they were trying to make a sound quality woofer with SPL also. Dual spiders (probably mirror image), and low inductance, fiber dust cap. I like it.

On that last note, since you are looking at quality sound and seem to have the budget for it, perhaps you should consider the Acoustic Elegance drivers. They are said to be world class.

- With respect to cabinets. Are their cabs specifically designed for each of the drivers I've listed?

- I don't know.....you would have to check it with a box program as I outlined above.

From my main LP, the left sub would be in a corner (1/2 wall is only 3 feet) while the right would be about 3 feet from its wall. The subs I will eventually build for near field will both be corner loaded and about 3-4 feet behind where I sit.

- I'm not sure that's nearfield? Usually, nearfield subs are only inches away from the seat.

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smcmillan2

· #4 · Oct 13, 2019

ratm said:
My absolute max budget when all 4 is done is $2k.

This pretty much rules out the HST and UXL if you're set on 4. PE has sales regularly, I was able to pick up a pair of UM-18 for just under $500, including tax.

ratm said:
- I was planning on using a iNuke 6000dsp as my amp each of the 2 amps. I like the DSP aspect and it seems cost effective.

I use an NX3000D to drive a pair of UM18-22 in ~4.8 net cuft sealed boxes on one channel, and a PA460 on the other. Produces great output in our living room "HT". The 6000 is not 2 ohm stable.

ratm said:
- I really like the completed dual box from DIY Sound group. Would two of these, one in front and one behind my main LP be a good option as opposed to 4 cabs?

Possibly, a sub crawl would tell you where they would work best.

Craig S King

· #5 · Oct 13, 2019

Why not go with 4 ported subs?

corradizo

· #6 · Oct 13, 2019

If this isn’t a dedicated space I’d look at (4) of these. https://www.css-audio.com/online-store/SDX12-and-Sealed-Flat-Pack-Kit-p112666933

ratm

Discussion Starter · #7 · Oct 13, 2019

Chris Popovich said:
The JTR is a well reviewed/liked solution, but I understand the DIY appeal for sure.

4 cabs gives you more placement flexibility and better individual eq control, but 2 can still be respectable. If you're used to just one sub now, and was able to integrate it successfully, then two will definitely work just fine.

Sealed is a lot more flexible and tolerant to design tweaks. 4cuft per driver works reasonably well for a variety of 18" drivers on the market. UM18-22's are great drivers, with 4 of whatever you choose you're going to be happy, just take your time with integration.

This seems to be the most cost effective way to get what I want.

ratm

Discussion Starter · #8 · Oct 13, 2019

smcmillan2 said:
I use an NX3000D to drive a pair of UM18-22 in ~4.8 net cuft sealed boxes on one channel, and a PA460 on the other. Produces great output in our living room "HT". The 6000 is not 2 ohm stable.

What does this mean?

smcmillan2

· #9 · Oct 13, 2019

smcmillan2 said:
The 6000 is not 2 ohm stable.

ratm said:

What does this mean?

Click to expand...

It means you don't want to try and drive a 2 ohm load with it. The 3k is stable at 2 ohms, so 2 UM18 each wired to 4 ohm, then parallel wired producing 2 ohms works fine per channel. Presents about 500w to each driver, so you can drive 4 UM18 off of 1 NX3k.

I know that's small potatoes to many around here, but the combination works great for us in our living room.

ratm

Discussion Starter · #10 · Oct 13, 2019

smcmillan2 said:
It means you don't want to try and drive a 2 ohm load with it. The 3k is stable at 2 ohms, so 2 UM18 each wired to 4 ohm, then parallel wired producing 2 ohms works fine per channel. Presents about 500w to each driver, so you can drive 4 UM18 off of 1 NX3k.

I know that's small potatoes to many around here, but the combination works great for us in our living room.

Ok, that concept makes sense. But the wiring doesnt. I would most likely get two NX3k so I dont have to stress them too hard IF I want to push them from time to time.

Trimlock

· #11 · Oct 13, 2019

hmm... too bad you need 4 drivers, the new Eminence NSW 21" works well in a sealed alignment and is $750 right now.

ratm

Discussion Starter · #12 · Oct 13, 2019

Trimlock said:
hmm... too bad you need 4 drivers, the new Eminence NSW 21" works well in a sealed alignment and is $750 right now.

I dont "need" 4. Just trying to smooth my response. Does anyone make a flat pack sealed 21"?

smcmillan2

· #13 · Oct 13, 2019

ratm said:
Ok, that concept makes sense. But the wiring doesnt.

Not sure what part doesn't make sense. The UM18-22 are DVC drivers, you either wire them to be 1 or 4 ohm loads (parallel vs. series). Then wire 2 of them to a channel on the amp, you either get 2 or 8 ohm load (again, parallel vs. series).

ratm said:
I would most likely get two NX3k so I dont have to stress them too hard IF I want to push them from time to time.

Ahh, it wasn't clear to me from your original post that 2 amps would be used. At that point the 3k would produce ~600w per driver, one per channel at 4 ohm each. That puts the UM18 to about max excursion in my boxes, should be a good fit for the 4cuft boxes PE offers.

Source of power output numbers: https://www.diyaudio.com/forums/class-d/213071-behringer-inuke-nu3000-measurements.html

Remy.Alexander

· #14 · Oct 14, 2019

Do it and dont look back- MDF is cheap, no need spend a lot of money on pre-made cabs. I run two 115s in 4.5 sealed and we prefer them over ported towers we built at 11ft3 each...so both sealed are smaller than one ported and they dig deeper. I run mine on a 3000DSp and it has no problems what so ever, Even when i ran both drivers in a 2ohm load, It was crazy good.

Trimlock

· #15 · Oct 14, 2019

ratm said:
I dont "need" 4. Just trying to smooth my response. Does anyone make a flat pack sealed 21"?

https://shop.gsgad.com/collections/21-home-theater-flat-packs

oops just realized you said sealed, don't know who does but if you have a cabinet maker near by you can contract one to make a few boxes if you supply them with what you want.

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