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

@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...

38Hz seem low, as you are using it between 18Hz and 38Hz? I went through a lot of pain for weeks with setting up 2 subs and I am curious about what I can learn from you.

@grislybutter 38Hz seem low...

Based on what I've read, I am trying it at 38Hz to 48Hz. The subwoofer is supposed to be able to go to like 18HZ. I realize that there is not a lot of recorded music that produces 18Hz, but after two days of messing with it; I can definitely say that the sound is a bit fuller. With some music, I believe I am hearing a bit more slam.

My presumption is setting the sub at a little bit higher than the Forte woofers, allows for reinforcement of the bass in the 38-48HZ./z region. I suppose this is where the extra slam and fullness originates. 

Of course, I could be completely wrong on this as I am no expert. I also suppose that the sub needs to break in? So then I get to adjust everything all over again?

I am still waiting on new longer interconnects to show up so that I can experiment  with the sub's position in the room, which will probably force me to start over again.?

The SVS instruction steps start with sub volume, then crossover point, then slope, then phase and polarity, etc.

I suspect that the trick is going to be frogging with it so that it blends with the Forte woofers. It is a fine line because it sure can go boomy and sound slow...  if I am  not careful. 

I went with a sealed woofer because I read a lot of comments that indicated a sealed sub does better than a ported sub with music. Having said that, I kept reading that Hsu subs are supposed to be "musical", but I believe that they are all ported!?

If I can get the one sub to blend, it will be an improvement. I can rationalize why two subs would sound better than one.

What I have read is that you should get the first sub to sound like you want and then work on the second one. Part of the process is getting the loudness right so that it does not overpower your speakers. Apparently, you have to reduce the first sub's volume when you add the second sub so that the overall loudness is correct with the speakers?

Now you know what I think I know! Please share your experiences with two subs to help me learn. Thanks! 

 

 

@dsper

here is my diary of my very simple and not at all sophisticated journey.

https://forum.audiogon.com/discussions/speakers-and-cables

There are obvious differences, such you have a big room and true full range speakers. The end of my story is that I just set it up as if I had speakers with an active sub at the floor level and I crossing over at 100Hz. 

That’s a good room dimension .

Set up on the long 35 ft dimension so there is a copious amount of space between you and the back wall.

Do you have a measurement mic? REW? If not, you may crawling for a long while and still probably mess something up.

If you don’t have measurement tools, try the following...Put the 2 subs along each side wall, 1 sub in front of listening position and 1 behind. Move each sub forward and backward from respective positions in small increments until a find the sweet paired spots along the side walls. Such paired placement will cancel out all the problem big nulls (for example, the widthwise ~37 hz, lengthwise nulls that might plague your spot). Perceptually, such relatively nearfield sub positions should also feel like you are floating in a uniform womb of bass...and provide just the right amount of tactile bass without it being distracting.

After you determine the right toe angle for speakers.... and with all that space behind you, you should be able to get some respectable envelopment and immersion from just stereo.

P.S. Also ensure that the subs you get have a variable phase knob, not some 0/180 flip switch (it is 2024).