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Discussion Starter #1
Hey guys. I'm building my 2nd house and 2nd theater. The new one is getting close as I'm spray foaming Monday and then drywall.

The new room has a foyer that has a theater ramp that leads to the top riser of a 16x22 room with 10.5' ceilings rows at 12 and 17. I currently have 3 QSC 2150s fed from a QSC 1644 that will be going in a baffle wall, an Epson 5030ub that will project on a 160" Seymour screen. I have 2 Volt 10s and just ordered 6 volt 10lx on the way for surrounds, Atmos, etc.

And 4 -18" SI HT D4 subs sitting in cardboard boxes.

I will have 2 subs in each front corner behind the baffle wall, and 1 in each rear corner in hidden alcoves. So 4 corner loaded subs which should give me tons of corner gain and a very good response throughout the room.

I can basically go as big as I need to volume wise. The thing is I only care about being flat to 10hz. I will easily hit reference with little power with these big boxes. Actually I will first try a single Inuke DSP3000 and run fronts and rears on seperate channels as the phase adjustments should be the same for each front and each rear. If I can't tune it right I'll add a 2nd amp. But a single amp should give each sub 400w and well exceed reference at 120db If my calculations are correct.

So here's the issue.. in Winisd (Yes i have the specs for the D4 so I'm not using the D2 listed on their web page) 21 cubes get's me flat to 14 hz. But that's a big ass box... I have the room but I have to carry 4 of these suckers upstairs :(. At almost half the size 12 cubes is flat to 17hz... similar to the Full Marty.

How much room gain can I expect. How low are the Full marty owners getting flat "in room" extension ?
 

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Your best bet would be to measure the gain of the room once it's built and then build subs that compliment the gain of the room. Also keep in mind that depending on the mechanical construction of the room it may not be possible to pressurize the room at 10Hz.
 

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For 4x 18ht shouldn't you run a 6000dsp?
Definitely would suggest the 6k for this job. He'd be leaving about 3dB on the table otherwise.

He'll want D4's to pull it all off, each sub wired as an 8ohm load, 2 subs per channel, wired to a 4 ohm load total.

That'd give him roughly 900w RMS per sub.
 

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sonotubes can be built huge and don't weigh anywhere near as much as mdf-based subs.


a couple of Pillars of Hercules may what you need. :)


what are the t/s parameters on the d4, btw? I haven't seen them.
 

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So why not a LLT? D4 in 20 cubes net tuned to 11 Hz or so will give smooth response down to 10Hz. You'd be best trying to measure your room gain with an existing sub to know what you'll get.

Definitely go for the NU6K. Better to have too much amp than not enough, and the amps roll off a bit as you get low in frequency; at 10 Hz the 6K may only be giving 1200W per channel or so.
 

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Discussion Starter #11
For 4x 18ht shouldn't you run a 6000dsp?
It depends on the size of the box. In an LLT style I can acheive very low Hz with little power, so really depends on the size of the box and room gain. These are all corner loaded so I'll have a ton of corner gain and should gave 5db of headroom above reference. I usually stay 5db below reference so that's estimated 10db of headroom.

If I have issues with adjusting phase and tuning to the room or have power issues I'll add a second DSP3000, so no biggie there.
 

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Discussion Starter #12 (Edited)
Is one in each corner ideal?
It's actually one of the better and smoother setups giving tons of corner gain(up to 12db) which being a HT that's all I care about. I designed the room stealing tons of ideas from here and doing tons of research. Building alcoves for them, I had to pick a known and tested configuration and go for it.

http://www.harman.com/EN-US/OurCompany/Innovation/Documents/White Papers/multsubs.pdf

http://www.audioholics.com/subwoofer-setup/multiple-subwoofer-setup-calibration-1
 

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Discussion Starter #13
sonotubes can be built huge and don't weigh anywhere near as much as mdf-based subs.


a couple of Pillars of Hercules may what you need. :)


what are the t/s parameters on the d4, btw? I haven't seen them.
I've built a sonotube 15 years ago..loved it. It holds a 15" dayton Quatro.. I sold it a few years ago to a buddy to go in his theater we made. Sonotubes won't work for me now, the alcoves are 30" wide , 18" deep, The screen wall is 18 from the wall as well, my real-estate is UP. No room for sonotubes.


The parameters are posted on here somewhere, I found them and entered them into WinIsd. They're slightly different than the D2. The D4 is a slightly better speaker according to SI, little better motor , not enough to matter though. It's all discussed on the thread I found the parameters on.

Basically I'm wondering do I need to tune that low or will it be a waste. Are guys with Marty or similar size/tune subs getting flat results to 10hz in room?
 

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I have found when trying to push the spl that corner loading is not the best for ported or sealed. In smaller c.f. that it can be boomy. Relection matter even with bass. Hopefully you have a bit of room to move stuff around if needed.
 

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I have found when trying to push the spl that corner loading is not the best for ported or sealed. In smaller c.f. that it can be boomy. Relection matter even with bass. Hopefully you have a bit of room to move stuff around if needed.
:confused: Do you know the difference between full space, half space, quarter space, etc?
 

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Discussion Starter #16 (Edited)
I have found when trying to push the spl that corner loading is not the best for ported or sealed. In smaller c.f. that it can be boomy. Relection matter even with bass. Hopefully you have a bit of room to move stuff around if needed.
I'm usually between corner loaded and 1/4 space, usually corner loaded. I've never really found anything boomy, of course boomy would mean your system needs to be eq'd, and I always measure and eq,but boomy or really bad response is primarily a single sub issue and bascically where you're sitting there's a peak that need to be Eq'd out if you wish to leave it in that corner. The multiple subs wont have the seat to seat peaks and nulls and trying to find that perfect spot in reference to the money seat isn't an issue.
 
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