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
Between using the corner or not is really a setup / integration issue from my experience. Since the corner is more active, it works best from my experience to leave a gap between where the bass in the speakers ends, and where the subwoofer takes over. If the sub is not in the corner there can be some overlap of the subwoofer and the bass of the main speakers.

The boom you hear in the corner under this assumption is that fact that there is too much bass at the cut-off frequency. The subwoofer, the speakers, and the corner of the room all taken together, is producing too much bass at that frequency.

If you adjust the subwoofer well in the corner, this gap will have bass partially from the speakers and partially from the subwoofer. If integrated in this way, you won't be able to tell where the speakers end and where the subwoofer takes over (Seemless integration).
Sugarbrie ... I have to disagree from personal experience. I had the REL on very little gain, with the rolloff down at about 25Hz and it still boomed away in the corner. The only way I could get good integration, and slam without boom was to bring it into the middle of the room.
I know you also have a sub (a REL I think) so I suspect that it's something to do with my room, perhaps that it's quite small.
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.