Subwoofer slam vs boom


Generally speaking what causes a subwoofer to be boomy, verses crisp and "slammy"?

Does placement and room acoustics greatly affect this, or is this just a common problem with lower end subs?

Currently I am using 2 HSU VTF-3's with opposite front corner placement, with all speakers set to large. The processor supports stereo subs, kinda a moot point with all large speakers thou. The subs should be doing the least amount of work possible, i.e. I am not rolling over 7 channels into one sub.

Thanks all
Marty
marty9876
I thought I was cheating by using all large speakers. In hind site for a ht setup this might not be true.

What is in the .1 track? I wonder if some frequencies are not being duplicated in both the mains and subs. What I have tried to do is let each piece of equipment do its own job, and not over load one piece.

I tried the subs out in the room, still not slamming. the subs are set about +2 db over the rest. This is not too high, I hope.

Before I got deeply into this hobby, I was at a friends house, listening to his rig. I have no idea what he had for equipment, since moved away and can not ask, but he played a demo disc and WOW. Some guy coughed and it felt like someone whacked me in the chest with a 2X4.

This crisp slam is what I am after.

Thanks all

Marty
I noticed the slam in my system vastly improved when I switched to a different amp in my woofers. I used to use IRS Betas with Adcom monoblocks and they had some good bass, but then I upgraded to the IRS V, which have a 2,000 watt amp in each tower. I believe that they are digital amps. Slam galore. Since it uses the same drivers as the betas and 12 woofers vs. 8, the biggest change was the amp. When listening to a bass cascade on Without Me from Eminem's The Eminem Show, it actually felt like I was falling. And on track 3, well, there is some slam. I must put a lot of it on the amp. Of course, the speakers have to be there to be driven as well, but it isn't just the speakers or the placement.
Seantaylor....I agree it can always just be your corner compared with the rooms I have integrated. Carpeting versus hardwood floors matters also. There is no one single way that works for all, as is everything in audio. That is why I also mentioned how overlapping the roll-off has worked for me away from the corner.

No matter what the cause, if someone is using a quality sub, with too much boom, it is probably a sign of too much bass at some frequency.

Richard E. Lord (REL) from what I have read, tried to designed his subs to go in the corner as a first resort, if possible. I think many people want the sub out of site, especially in Europe.
Marty if you're after slam & dynamics without the boom; check out Tom Danley's ServoDrive ... the contrabass are killer!
http://www.servodrive.com/
http://www.mindspring.com/~sdinc/pages/contra.html
The reason you have sloppy bass is probably the fact that you have so many different drivers trying to move air at low frequencies. When it comes to tight bass less is sometimes more. The less things you ask of each component, the better they can work. The first thing you should try is setting your speakers to small and allowing your subs to take over below 90hz (usually the point most preamps/av receivers are set to). You may even want to go with a single sub- the VTF-3 puts out quite a bit of bass from what i've heard. I don't know what kind of bass management capabilities your processer has but you may want to invest in outlaw audio's icbm. This will allow you to fine tune each speaker's crossover point with the subs, particularly helpful if some of your speakers produce nice bass below 90hz. Lastly, two woofers operating in phase fireing opposite each other will cancel each other out, you may want to adjust the phase of the subwoofers. Keep in mind two subs do not equal twice as much bass, the only reason you should use a second sub in a room is to account for an odd shaped room that may have some sort of acoustical imbalance (i.e. open on one end). You may even be drawing too much AC out of the wall, five speakers and two subs, plus a TV if you are watching a movie will draw a hellava lot of current. This should be easy to spot b/c your lights will flicker- turn something off!. With your equipment you should be able to loosen fillings, bowels, cement and so on, its just a matter of proper setup. Let us know how it goes-