Choose 2 subs for my new theater room! (Details inside)

[Landmonster]

Hi guys.

So after being on this forum and trying to learn about subwoofers, I still am confused. I have held off on buying anything, because I knew I'd be moving soon, and I didn't want to buy anything for my old space that would not work in whatever new house I bought.

Well, I am closing on a new house soon, which has a dedicated media room. It is not as huge as I'd prefer... but here are the dimensions: 10.5 feet wide, x 20 feet deep. (Pictures are attached, with the previous homeowner's gear inside... not my gear)


The previous subs I had been looking at were the :

• Monolith 12 or 15
• Rythmik Fv15HP
• SVS PB-4000 or SVS16 ultra
• JTR subs

I have an eye towards good aesthetics and super clean output, over massive SPL. I was leaning towards one of the SVS subs in Piano black, but I was also interested in the Monolith subs due to their on-paper very low distortion ratings. However, in the real world, I'm not sure how extremely low distortion translates into listening experience from a sub.

Of the subs listed, which would be a smart choice?
Is this room too small for 2 large subs?
Would I be better off going with 2 small/medium subs, or just 1 large sub?


Note:

1. This theater is up for a full redesign... audio, video, wall color, seating, etc. The current owner has in-wall, and in-ceiling speakers, as well as some type of projector + screen that I will be most likely replacing.
2. The interior room width is 10.5 feet from wall to wall. The room depth is 20 feet deep, and has 2 doors that close.
3. I will choose more compact seating than what is in there now.
4. I could use other help for this theater design, aside from subs
   

 

[ryanosaur]

In a room this size, ~2000cu.ft? I would begin considering 3-4 sealed subs. I'm not usually the guy to say this, either, but save on floor space and take advantage of cabin gain.
3 Hsu ULS 15, or SB3000 from SVS?

 

[Landmonster]

Floor space will be at a premium, sadly.

Why are you recommending sealed subs, just due to floor space savings?

 

[mazersteven]

1- PB-4000 would work great. Or 2 PB-3000's. Dual 4000's would be Awesome

 

[CajunLB]

If you’re into diy I think a pair of 12”\15” Dayton Ultimax sealed kits would be great in,that size room. Then you can paint or veneer any way you like.

 

[ryanosaur]

Floor space will be at a premium, sadly.

Why are you recommending sealed subs, just due to floor space savings?

In rooms below, say for convenience sake, 3000cu.ft, you get the benefit of cabin gain. This phenomena in its most basic description will make the subs sound bigger.
Usually we advise against sealed because you lose output below the tuning frequency. I don't know that cabin gain can make up for it, but closing that door when you engage your theater will allow that much smaller space to be pressurized much more efficiently than what I recall you discussing before.
Here is a recent vid from Erin who is active here and on several other forums. He is also doing measurements on par, and even exceeding at times, what Shady does.

He gives a very good description of what's going on with room gain and why I would even consider suggesting it to you.

 

[shadyJ]

JTRs are easily the highest performers on that list, but they are also the most expensive. If you can afford them, a couple Captivator S1s would be pretty killer in a room like that. Or better yet, Captiavator 2400s. Captivators S1s will save you a lot of floor space.

I would rule out the SVS PB16-Ultra. Killer sub, but it has a very large footprint. A good SVS sub that will have a lot of deep bass output for a small footprint would be the PC-4000. For your situation, that would be my choice among SVS subs.

Rythmik FV15HP is a fine sub, although it is the only one I haven't heard from your list. It does have a pretty significant footprint though.

The Monolith 15" THX Ultra is a big sub that will eat up a lot of space. Like you say though, it does have near textbook-perfect performance. The Monolith 12" THX Ultra is more reasonably sized. It's still large for a 12" sub; It's not that much smaller than a Hsu VT15h mk2- but the Hsu is a higher performer. I would go with a Hsu 15" over the Monolith 12".

Two of any of these subs will get you massive bass in a room that small. Just massive. Something else to think about is getting three or four smaller subs to help even out the room response. Maybe take a look at getting some Outlaw Ultra-X12s or Hsu VTF-2 mk5s or SVS PC-2000s. That will still get you massive bass but three or four of them will go a lot further on smoothing out the room response than two behemoths.

Some more advice for a room like that:
It's a narrow room, and you don't want to put your speakers really close to the sidewall. However, if you are angling for a large screen, that might be unavoidable. If you have to place the speakers very close to the sidewall, I would recommend placing some broadband acoustic absorbers along the wall in front of the speaker. The thicker, the better. 2" thick absorbers would be OK, but 4" thick absorbers would be better.

For seating, the existing arrangement, as you have surmised, is suboptimal. Having seating so far to the left or right basically means there isn't a good seat in the house. You will want a set up with a centered seat, a "sweet spot." If you don't want to look too selfish for your family, use a loveseat type sofa or something like that. One thing people do a lot that wrecks the sound is they get these big home theater seats. There are a bunch of problems with these as they relate to sound. First, the high back blocks your ears from the surround sound speakers! A lot of dudes will buy big, expensive, electrically adjustable seats that end up defeating the point of having a surround sound system! Don't get anything that has a huge headrest.

Second, many of those seats have leather upholstery. But many types of leather will reflect sound much better than they will absorb it. So it's like listening to a sound system with an acoustically reflective surface right behind you. That does no favors for sound quality. Again, another argument against high-backed seating.

The room is quite narrow so I would think about just using in-walls for the side surrounds or else the speakers can really get in the way.

So you have Polk LSiM 707s. Those speakers have a crazy low crossover to the bass drivers at 100Hz. I would try to take that crossover element out of the equation as much as possible, by using a high crossover frequency for the subs. Experiment with a 100hz or even 120Hz crossover to the subs.

Before you had mentioned going 9.x.4 instead of 7.x.4. There are some advantages of the front wide speakers in a 9 channels bed system, however, I think your room is just too small for that. I would go with 7.x.4. Try to use in-ceiling speakers as the heights if possible, but I suspect you already know that.

If you have the money, you really should think about getting the Monoprice HTP-1 for a processor. Let's say you get a 7.4.4 system; the HTP-1 can independently calibrate up to 5 different subwoofers, using Dirac's bass control system Dirac's bass control for multiple subs is a $500 upcharge though, but if you want to calibrate your system to perfection, it's worth it. The HTP-1 supports that feature.

Another argument for getting a processor like the HTP-1 is that your speakers really benefit from an outboard amp. A Polk LSiM set is going to put a lot of stress on the amp in an AVR. You will want an amp that is comfortable with low-impedance loads. Outlaw Audio and Monoprice Monolith have some great affordable amps. I am sure Emotiva does as well.

 

[Landmonster]

I do need some help with the logistical placement of all this equipment.


Current system is:
2x Polk LSiM 707towers (front L and R)
1x Polk LSiM 706c for center

Additional speakers that COULD be used in surround config:
4x Polk LSiM 702fx (wall mounted surrounds)
2x Polk LSiM 705 tower
2x Polk LSiM 703 bookshelf

I have an Emotiva XPA7 for the amplifier, and a Denon X4500... which is limited to 11.2 processing.


These speakers do not ALL have to go inside this room. In fact, 4 of the LSiM 702s could still be returned. I only purchased them because they were on close out, and I thought they might be a good idea for a room this narrow.

I was looking to create a 7.x.4 atmos setup, or a 9.x.4 atmos setup. I feel like it it needs more than 5 speakers on the base layer because the room is 20 feet deep.

However, as you say Shady, it may be too narrow to go with "front wides", since the front sound stage is only 10.5 feet wide, unless I am using the 702 FX as the front wides, with the tweeter angled at the main listening position. I'm not sure if that is a good idea.

Would these be a decent idea as front wide?

Or only used as side-surrounds behind the main listening position?

Scrap these alltogether for this room?

 

[Landmonster]

I do need 2 subs, and a processor, and to figure out seating and speaker placement still.

 

[William Lemmerhirt]

I second shadys post and only add to agree to skip front wides. There’s not much support for them natively and I think DSU, or DTSnx(cant remember which one off hand) won’t support them either. 20’ isn’t that long of a room imo. 7.x.4 will be perfect.
I think if going with SVS a pair of cylinders will be fantastic. Just a great use of space. The 2000’s will be plenty for that space, but the 4000’s will be even better, with more headroom than you’d likely ever need.
And definitely agree with a “sweet spot” type of seating.

 

[vader540is]

I do need 2 subs, and a processor, and to figure out seating and speaker placement still.

Two Subs.


Power Sound Audio TV1812

JTR cap2400

Rythmik FV18

 

[Landmonster]

I second shadys post and only add to agree to skip front wides. There’s not much support for them natively and I think DSU, or DTSnx(cant remember which one off hand) won’t support them either. 20’ isn’t that long of a room imo. 7.x.4 will be perfect.
I think if going with SVS a pair of cylinders will be fantastic. Just a great use of space. The 2000’s will be plenty for that space, but the 4000’s will be even better, with more headroom than you’d likely ever need.
And definitely agree with a “sweet spot” type of seating.

Thanks William.

If I stick with 7.2.4,

How would I orient the side surrounds in a room this narrow? I basically have 3 options that I see

• Wall mount 2 Polk 702s, as seen above.
• install some kind of in wall speakers?
• Set 2 Polk 705 or 703 towers very close to the wall?

For the rear surrounds, I planned on using the Polk 705 or 703. The rear wall itself is slightly uneven, which is why I wasn't planning on using the 702s for that duty, unless you have a smart work-around.

 

[AcuDefTechGuy]

Floor space will be at a premium.

I would move the audio rack forward about 7". Then HIDE one RBH SI-1010 passive sub BEHIND the audio rack since the SI-1010 is only 6" deep. If that is not enough bass for you, you can always add another SI-1010 sub (probably stack them on top of each other).

You can use practically any amp to power the SI-1010 subs.

 

[mazersteven]

I like using those 705's for the side surrounds I just don't know how you would do it

 

[William Lemmerhirt]

Thanks William.

If I stick with 7.2.4,

How would I orient the side surrounds in a room this narrow? I basically have 3 options that I see

• Wall mount 2 Polk 702s, as seen above.
• install some kind of in wall speakers?
• Set 2 Polk 705 or 703 towers very close to the wall?

For the rear surrounds, I planned on using the Polk 705 or 703. The rear wall itself is slightly uneven, which is why I wasn't planning on using the 702s for that duty, unless you have a smart work-around.

Being that narrow, I think I’d go in wall for side surrounds to avoid hot spotting. MAYBE some shallow bipoles, but I ended up with IW sides, and imo they’re better than bipoles performance wise. I would also place the sides at 80° instead of 90-110. That will help tie them to the mains, and give a little more separation from the rear surrounds.
That back wall is really something. I think would use the 703’s on stands(will try and make a doodle for suggestions). The 705’s would make nice rear surrounds but definitely not worth the cost. Wish I could stand in the space. Makes it a lot easier, even though the pics are pretty good.

 

[Landmonster]

Being that narrow, I think I’d go in wall for side surrounds to avoid hot spotting. MAYBE some shallow bipoles, but I ended up with IW sides, and imo they’re better than bipoles performance wise. I would also place the sides at 80° instead of 90-110. That will help tie them to the mains, and give a little more separation from the rear surrounds.
That back wall is really something. I think would use the 703’s on stands(will try and make a doodle for suggestions). The 705’s would make nice rear surrounds but definitely not worth the cost. Wish I could stand in the space. Makes it a lot easier, even though the pics are pretty good.

I do already own the 2 705s, and 2 703s. I've owned them about a year. I could use all 4 of them in the room if space permits somehow.

The 4 702s I just purchased on close-out, they could be returned.


The in wall matching speakers are these: https://www.amazon.com/Polk-Audio-Rectangular-Performance-Speaker/dp/B008SDTRIC

I'm not sure what would be the highest-performance option.

 

[mazersteven]

The highest-performing would be to use the towers and bookshelves that you already own 705 703 but will they integrate into the room is the question and hurt performance

 

[stalag2005]

I own a SB 3000 from SVS and a Paradigm Defiance X12. For what it is, the X12 puts out a massive amount of low end base for what it is. SVS has like a 3 HZ lower extension, but the X12 I prefer more especially since it sits in a much larger area. For the pricing of an SB 4000 SVS sub, the Paradigm Defiance would be a worthy consideration IMHO. If space is a major issue, the SVS PC-4000 should suffice. However I would call SVS as it looks like their website is not showing their 4000 series lineup for me.

 

[Landmonster]

There doesn't seem to be much love in this thread for the Monolith sub line.

Correct me if I am mistaken in my line of thinking here:

If 2 of the Monolith 12s would have a great amount of output for a room of that size, and they have one of the lowest levels of distortion available, what would I be gaining by going to another sub?

• More headroom that is never utilized?
• More tactile or pressurizing feel somehow?
• Cleaner sounding output, despite having more THD+N?
• Something else?

 

[ryanosaur]

There doesn't seem to be much love in this thread for the Monolith sub line.

Correct me if I am mistaken in my line of thinking here:

If 2 of the Monolith 12s would have a great amount of output for a room of that size, and they have one of the lowest levels of distortion available, what would I be gaining by going to another sub?

• More headroom that is never utilized?
• More tactile or pressurizing feel somehow?
• Cleaner sounding output, despite having more THD+N?
• Something else?

Monolith Subs are well reviewed and liked. Shady reviewed them... glowingly, iirc.

They aren't lookers, but they would be good Subs for that room. A pair of them, placed properly, would give you a very good experience, I think.