One sub or two?
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More is always better.
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Your room is around 1,500 ft^3. If the room isn't open to other large areas, one VTF-15H MK2 should be more than enough. As long as you will have multiple spots to place the sub and find the "hot spot" for your seating area, this sub should crush it in this size room. Two would be crazy. A cheaper solution if you wanted two would be to get a less expensive, less capable sub and place it near-field to the MLP. I've experimented with this and had great success.
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The point of getting two subwoofers is to even out the response by stimulating more room modes. When you place them, you should aim for asymmetry in their placement with respect to the room modes so they are not both driving the same resonances. That means either offsetting your listening space or placing them asymmetrically with respect to the main listening position, unless the room itself is asymmetrical in which case you might get lucky and not have to do anything special at all.
If one sub sounds fine at your main listening position and the setup is completely symmetrical, two subs in a completely symmetrical setup may smooth out the response in the off-center listening positions because more room modes are stimulated at those points, but may not help much in the main listening position when the modes at the main listening position share a lateral symmetry. Moving the listening position along the line of symmetry will change the response but will not gain any benefit from two subwoofers so all your center seats may have issues with not enough room modes if your subwoofer placement and room is symmetrical left-right.
At the same time, you also need to aim for equal distance to the main listening position unless you also have subeq or whatever it is called on your system where the receiver time-aligns the subs independently at cal, or else you need to do it yourself with the adjustments on the subwoofers themselves. Depending on the implementation of the delay on your subwoofers, it may be literally impossible to time align them well with only their own controls, especially if they have analog signal path because in that case the phase adjustment likely has strongly varying delay for varying frequency. However many people do exactly this and report improved response overall. Additionally, in such asymmetrical placement the sound may suffer outside the main listening position because the time alignment between them changes if the absolute difference in distance from each subwoofer changes. It really depends on how much the time alignment changes with position, what modes are stimulated at each position, etc.
When using two subwoofers you can use less powerful subs but you still need the extension to get the same infrasonic effect. That could mean the only option is to put way more subwoofer than you need to get both smooth response and infrasonics simultaneously because less powerful subs also usually have less extension.
I have two pb10s in an apartment with 12'x14' listening space. The apartment has kitchenette hall bath and bedroom attached to one side of the living room so the actual space is about two to three times larger than that depending on which doors are open. The attached rooms by definition make the space asymmetrical so one sub ends up near a corner and one ends up in the center of the wall and the response in here is smooth as glass even with symmetrical setup because it is offset in the room.
The subs are way more than I need in here but I went with the pb10s because I wanted flat to 20Hz. In room response is somewhat better than that because of boundary reinforcement.
Even with these overpowered subs I still do not get strong infrasonic output in this space. They are not capable of 10Hz impact and barely output anything audible to 14Hz.
Hope this helps.
If one sub sounds fine at your main listening position and the setup is completely symmetrical, two subs in a completely symmetrical setup may smooth out the response in the off-center listening positions because more room modes are stimulated at those points, but may not help much in the main listening position when the modes at the main listening position share a lateral symmetry. Moving the listening position along the line of symmetry will change the response but will not gain any benefit from two subwoofers so all your center seats may have issues with not enough room modes if your subwoofer placement and room is symmetrical left-right.
At the same time, you also need to aim for equal distance to the main listening position unless you also have subeq or whatever it is called on your system where the receiver time-aligns the subs independently at cal, or else you need to do it yourself with the adjustments on the subwoofers themselves. Depending on the implementation of the delay on your subwoofers, it may be literally impossible to time align them well with only their own controls, especially if they have analog signal path because in that case the phase adjustment likely has strongly varying delay for varying frequency. However many people do exactly this and report improved response overall. Additionally, in such asymmetrical placement the sound may suffer outside the main listening position because the time alignment between them changes if the absolute difference in distance from each subwoofer changes. It really depends on how much the time alignment changes with position, what modes are stimulated at each position, etc.
When using two subwoofers you can use less powerful subs but you still need the extension to get the same infrasonic effect. That could mean the only option is to put way more subwoofer than you need to get both smooth response and infrasonics simultaneously because less powerful subs also usually have less extension.
I have two pb10s in an apartment with 12'x14' listening space. The apartment has kitchenette hall bath and bedroom attached to one side of the living room so the actual space is about two to three times larger than that depending on which doors are open. The attached rooms by definition make the space asymmetrical so one sub ends up near a corner and one ends up in the center of the wall and the response in here is smooth as glass even with symmetrical setup because it is offset in the room.
The subs are way more than I need in here but I went with the pb10s because I wanted flat to 20Hz. In room response is somewhat better than that because of boundary reinforcement.
Even with these overpowered subs I still do not get strong infrasonic output in this space. They are not capable of 10Hz impact and barely output anything audible to 14Hz.
Hope this helps.
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This is another way to get smoother response and many people report good results. Never tried it myself. Atlantic Technology has produced mismatched subwoofer sets for exactly this sort of application. It is sort of a two-way subwoofer implementation, dividing frequencies between tailored systems.
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Very near placement of subwoofer changes the acoustics in some esoteric way. The dBs and sound pressure level do not track each other with distance. If you want to really feel the bass nearfield placement is a good way to do that because you will feel the spl but as indicated here it may not be all that pleasant if it is too close to you and too capable in extension. Probably better with smaller sub for that feeling of 'slam'. Not sure, no experience but this is what I read elsewhere on the forum.
I hear ya. The MK1 must be a little too big and little too powerful to sit only inches from.
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Try this one on for size:
http://www.avsforum.com/forum/155-d...asses-one-sub-126db-16hz-22.html#post31083058
Big enough for you?
Try this one on for size:
http://www.avsforum.com/forum/155-d...asses-one-sub-126db-16hz-22.html#post31083058
Big enough for you?
It'll have to do if that's the biggest I can get.
Thx for the replies. The only placement options I have for the sub(s) is below the screen between the front speakers and the center channel or behind the front left/ right speakers. If I put one sub next to the center channel and one behind the left/ right speaker, will that even out the response?
The only way to know for sure is to measure the response.
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If you have more than one row of seating, no probably not. Usually it's best to have one sub up front and one in back to even out response, but like Shady said, the only way to find out is to measure (REW link in my sig).
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