Subwoofers and Seating Position for Klipsch Forte iv's


Hi All, 

I am trying understand seating position and subwoofer size/power requirements.

My room is 35 X 15 x 8 = 4200 cubic feet. The room setup (music only and no HT) is such that my main speakers are on one end of the 35 foot length and my seating position is about 11 feet from the speakers, such that half of the 35 foot length is behind me. There is nothing obstructing the whole 35 foot length except the seating position.

My thought is that I would obtain two subwoofers and start with them on the same end of the room as the main speakers. I realize room modes may impact subwoofer positions, but I am hallucinating that only one of the subwoofers would  ever come further into the room than on either side of the listening position and not end up at the other end of the 35 foot length.

So I am imagining that I am really trying to energize just the half of the room that is closest to the main speakers.

My speakers are Klipsch Forte iv's connected to a Don Sachs preamp and then to a variety of amps between 25 and 100 wpc per channel (Van Alstine, FW F7, DS  Kootenay, and Quicksilver horn monos). The Fortes are specified as handling 100 wpc continuous at 112 decibels. 

I used to run Thiel CS5i's in this same space and a McCormack DNA 500 would provide "in my chest" bass response when I cranked it.

Been looking at HSU (15 inch & 450 watts, SVS (13 inch & 800 watts), and Rhythmic (12 inch & 400 watts) as these manufacturers seem to garner good reviews for being musical without going beyond the $900 to $1200 per sub range.

Any advice or suggestions would be appreciated.

Thanks for listening,

Dsper

 

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dsper

Having speakers far out from the walls is seldom the best location, usually results in weak bass when applied to full range speakers, and ruins the feng shui of nearly any living space.

@perkadin  It depends what you mean by “far,” but go to any audio show or high-end dealer and the speakers are always well away from the walls unless they’re designed specifically to be near the walls, but those speakers are few and far between.  But point taken that going too far can result in negative results as well so it’s all about finding what works for someone’s specific tastes, speakers, and room.
 

Subs, or more specifically bass, is omni directional.  They are also adjustable in output and phase so they can sound good in a location where they also look the best. 

This is just factually incorrect.  To get subs to work best within a room they need to be placed carefully so as not to excite room modes and provide even bass response, and output and phase can’t fully correct for that.  Even if you use room correction that can’t do much if anything to improve room nulls — only proper placement can do that.  Just because bass is omnidirectional below a certain point does not mean you can just plop them anywhere — the room dictates where subs sound best and that just takes some work to get right unless you do something like a Swarm as mentioned earlier.

 

are you planning to match 2.5K subwoofers to 5K speakers that already have a lot of bass? 

@soix how exactly does one carefully place their subwoofer?  Do you move it all around the room, tweaking phase and output settings to eliminate bad choices?  Is it inch by inch or foot by foot?  Are you using music or sound tones?  What if you have two subs?  There are limitless permutations. 

Or do you simply find a spot that you think will work that also looks good and dial it in?  There's no need to be neurotic about it, you are talking about 20-80hz which makes up a very tiny slice of recorded music. And as I said earlier, for the most part it's omnidirectional. Tuning a sub is basically eliminating unwanted vibrations while getting sufficient output. If you have a big room like OP's you'll probably need a second sub.  

how exactly does one carefully place their subwoofer?

@perkadin There are programs designed to help like RPG, etc., but the crawl method I mentioned earlier is very effective and doesn’t require additional software, microphones, etc.

https://www.audioholics.com/home-theater-connection/crawling-for-bass-subwoofer-placement

If you wanna understand more of the theory of sub placement there’s a good intro in this video, but you can google Todd Welti on whose work a lot of this info is based.

https://www.youtube.com/watch?v=InwRYDzgEQk

So it’s not as easy as just plop them wherever they look good and change some settings to get really good bass in a given room — there’s just a lot more to it than that.

@grislybutter are you planning to match 2.5K subwoofers to 5K speakers that already have a lot of bass? 

Yeah, I guess I am. The Forte iv's are specified at 38Hz. The last speakers I had for any length of time were Thiel CS5i's that went down to 23Hz. I like the dynamics and sensitivity of the Forte iv's but I also think that, well, they are a bit thin and a bit off in tone. I am considering subs as a way to possibly correct for some of this without pumping bucks into more expensive speakers. If this does not work then it is on to Volti, Tannoy or who knows.

All,

I have purchased a SVS SB3000 subwoofer that arrived yesterday. With just the one sub, I can tell a difference; the sound is ...just more heavy, fuller, I guess. Initially it also sounded a bit boomy. I have it crossed over at 38Hz and am fussing with volume, phase, crossover slope, etc. All sorts of fun. The SVS app is nice as you can make adjustments while in the sweet spot. 

Have not done the crawl yet.

From what I think I can hear, I suspect that two subs would be better than one. Yes, bass is not supposed to be directional, but my impression is that, with the sub placed just inside of my right speaker, the bass is emanating from that side. Might just sound that way because of the visual...I have longer interconnects arriving tomorrow so I can move the sub around.

Stay tuned...