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Discussion Starter · #1 · (Edited)
Below are some pics of my theater room. I'm new to DIY subs, but have built many enclosures for cars over the years, and reading the forums recently has got me highly motivated.
I'm considering adding two 85 liter sealed enclosures up front in the Salamander cabinet to the right and left of the center channel. The cabinets are super sold, with all doors and sides being perforated, and I've run subs in the cabinets before.

I originally considered Ultimax 15s, but lately I've been interested in the HST-15s Nick has available (not listed on the site). They have the same power handling and Xmax as the HST-18 and work well 85 liter enclosure. They have higher SPL than the UM-15 at about 28 hz and below in that 85 liter enclosure with RMS rated watts.

I'm wondering if it might make sense to go with a lessor driver and use four of them in the home theater? The room is only 11'4" x 21'9" x 8'. The second set of subs would go behind the theater sofa, but not sure if that's even the route to take. Any thoughts on the best setup here? My priorities are sound quality, low end extension, SPL and max 85L enclosures (19.25"x19.25"x20" flat packs). I tend to prefer sealed enclosures. Thanks for any advice you can give.
 

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Discussion Starter · #2 ·
As I think about this more, I guess the real question is..."Since the price of the Stereo Integrity HST-15 is double for the subs+cabinets and 50% more for amp power, is the increase in cone excursion and 10-28hz SPL worth the additional cost for the purpose of watching movies at high volumes?"
 

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I have not built any subs using SI drivers, But I have with the Ultimax. I currently am running 2 sealed um15s in front and 1 large ported um15 back left. Must have gotten lucky that they play very well together (sealed and ported). I smile every time I listen to music or movies.
 

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Discussion Starter · #4 ·
I have not built any subs using SI drivers, But I have with the Ultimax. I currently am running 2 sealed um15s in front and 1 large ported um15 back left. Must have gotten lucky that they play very well together (sealed and ported). I smile every time I listen to music or movies.
Thanks, what size enclosures for the sealed and ported? What are you feeding them with? Do you use a DSP?
 

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that room is going to be tough for modes.


might want to give this thread a read through:
http://www.avsforum.com/forum/155-d...y-1262w-s-using-diysoundgroup-flat-packs.html


with small sealed cabs lots of placement options can be explored (including stacking) until a decent response is achieved across most of the seats.


a pair on the front, a pair on the sides, a pair or two pair stacked in the rear, etc... the 1262w are so low cost, it is possible.


http://www.harman.com/EN-US/OurCompany/Innovation/Documents/White%20Papers/multsubs.pdf
 

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that room is going to be tough for modes...
+1
I would go with 1 centered on the front wall and one centered on the back wall at a minimum. You have a small enough space to support a good sealed design with room gain too. Take your pick: Dayton 18 HO, SI HT18, UM18. One front & another in the back in down firing sealed boxes with a NU3000DSP would be perfect.
 

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Discussion Starter · #10 · (Edited)
that room is going to be tough for modes.


might want to give this thread a read through:
http://www.avsforum.com/forum/155-d...y-1262w-s-using-diysoundgroup-flat-packs.html


with small sealed cabs lots of placement options can be explored (including stacking) until a decent response is achieved across most of the seats.


a pair on the front, a pair on the sides, a pair or two pair stacked in the rear, etc... the 1262w are so low cost, it is possible.


http://www.harman.com/EN-US/OurCompany/Innovation/Documents/White%20Papers/multsubs.pdf
Exact measurements are: 11'4" x 21'9" x 8'. I've placed a 15" sealed subwoofer on the primary listening position (center seat, off center in room), then used an SPL meter at various positions. The rear corners and to the left and right of the center channel were relatively high dB, although not the highest points in the room from what I recall. Those are definitely the convenient positions for subs given my current configuration.

Is there a free app I can use for modeling the room?
 

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Exact measurements are: 11'4" x 21'9" x 8'. I've placed a 15" sealed subwoofer on the primary listening position (center seat, off center in room), then used an SPL meter at various positions. The rear corners and to the left and right of the center channel were relatively high dB, although not the highest points in the room from what I recall. Those are definitely the convenient positions for subs given my current configuration.

Is there a free app I can use for modeling the room?

Room EQ Wizard

If you put a sub in each of those 4 positions you should get a nice even response. However, just using 1 or 2 of them will likely give you an uneven response at the MLP.
 

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They tested with a coherent signal, meaning no delays were used to account for different distances between the subwoofers and the MLA. We can easily add delays to subwoofers now so it's hard to say what value the white paper still has (if you're not limited to a coherent signal), or how the results might be different if re-done, but with the subs time aligned to the center of the MLA.
 

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yeah, that aspect and others (such as variation in boundary losses and inclusion of subs in the height dimension) complicate things greatly. intuitively, it strikes me that the geometrical conclusions are valid with respect to minimizing seat to seat variation, even allowing for individual phase/delay adjustments, BUT i'm not breaking out matlab in order to find out!
 

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Are you only considering two subs due to cost or/and size restrictions? The HT18 is a bargain and going in a sealed box the price of four would be less than two HST15's. More subs would give you better smoothing as well.

My room has many issues only until I went past six subs did I start getting a flat response.
 

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Discussion Starter · #15 ·
Are you only considering two subs due to cost or/and size restrictions? The HT18 is a bargain and going in a sealed box the price of four would be less than two HST15's. More subs would give you better smoothing as well.

My room has many issues only until I went past six subs did I start getting a flat response.
The reason I was looking at a 15" sub was due to restraints with fitting a 4 cubic foot enclosure in my cabinet. I've addressed that. I can slightly modify the 4 cu ft flat pack and get them to work. I'm thinking four subs long term, two in front next to the center channel in the cabinets and two in the back corners.

Now, the question is do I go with the Ultimax-18 with cabinet from Parts Express, or go with the SI HT-18 and purchase the cabinet separate from DIY Sound Group. Because of the $92 shipping charge for each pair from DIY Sound Group, the cost for a pair of subs with cabinet and a single NU6000DSP is identical whether I go HT-18 or UM-18.

Pros for UM-18
- Max SPL is 1.5dB higher from about 50 hz and down in 107 liter enclosure, according to WinISD

Cons for UM-18
- Because of the dual 2 ohm voicecoils I would need a single nu6000dsp for each pair. This would allow me to use the DSP on each sub separately however.

Pros for HT-18
- Since they can be ordered in dual 4-ohm voicecoils I could run two at 8 ohms per channel, then when I move to four subs I could run two per channel at 4 ohms, saving $400 on the second nu6000dsp.

Cons for HT-18
- If I use a single nu6000dsp for four subs I won't be able to DSP each sub separately. I would use one channel for rear and one for front, I assume.

If anyone has any thoughts on sound quality of the HT-18 vs UM-18 for movies, please let me know. Also, in this situation should I be using the DSP on each sub separately? Last, in order to fit the 18" driver, I would be running the NU6000DSP in a room 50 feet away. What considerations should I take in running the Denon 3812ci sub output 50' and then 10 gauge (?) speaker cable 50' back to the subs. Best part of that is no fan mod though! Thank you.
 

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Discussion Starter · #17 ·
Thanks BassThatHz.

Does anyone have any comments on using the iNuke DSP to EQ two subs on the same channel? In this case it might look like running two HT-18s in the front of the room off one channel, then two HT-18s in the back of the room off the second channel? This as opposed to having four discrete channels/DSPs for the four subs....and I'm not talking ohm considerations, more just cons of doing one DSP channel on two subs.
 

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if you and the subs are relative symmetrical, separate eq on the front set as a pair and then a separate eq on the reat set as a pair works.
My experience is that this doesn't work all that well. You can end up with two sets of subs that are EQ'd reasonably flat when played in their set, but as soon as you combine the two sets the FR goes to crap.
 

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the suggestion wasn't that each set be eq'd optimally, then both sets run together.
the suggestion was simply that a front set and a rear set eq'd as sets is fine so long as their relationship to the LP is symmetrical.
 
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