Bass impact vs room size vs number of subs

[Hocky]

I recently built out a new HT room after moving to a new house and I am not crazy about the amount of impact that I get from the subwoofers. I mean, it sounds good and can achieve high SPL, but it just doesn't have the impact that it used to in my old room. I am not sure if this is due to the construction / layout of the room or if I just need to add more subwoofers to pressurize the room harder. The FR is pretty solid being +2/-3db from 16hz to 200, so I don't need any help there, it is just lacking in physical slam/impact a bit. It is a 6000ish cubic foot room that is in a basement, so drywall -> insulation -> air gap -> concrete on most surrounding walls. Currently, I am using a pair of SVS PB13 Ultras. I really want more impact. If I add one or two more PB13's (either colocated or somewhere else in the room), am I really going to gain impact at the same SPL in the room? Or am I just going to be wasting my time?

 

[lovinthehd]

The old room have wood construction vs the new room's concrete by chance? What was the cuft of the old room? Are either of the subs nearfield? I have a 6500 cuft room with wood floors and four subs (3 x 18" sealed and a sealed dual opposed 15") with one of the 18"s right behind my seat for some more tactile/slam. You might consider tactile transducers in your seating as well as more subwoofage IMO.

 

[Hocky]

Yea, the old room was a first floor slab, drywall, wood framed walls. The old room's size is hard to calculate because it was very open, but it was in the ballpark of this one. Subs are currently both around 12-15' away.

 

[lovinthehd]

There are guys with super sub systems in concrete dominated rooms that still find benefit with tactile transducers. Try moving a sub nearfield to see if that helps.

 

[ski2xblack]

A lot of that "slam/impact" is due to frequencies above those your subs produce. I suspect the dynamic range of your ML mains may be a limiting factor.

 

[Hocky]

My ML's have 2 10" woofers each playing up to 350hz. There isn't a lack of impact spl capability there.

 

[lovinthehd]

My ML's have 2 10" woofers each playing up to 350hz. There isn't a lack of impact spl capability there.

Where do you cross the speakers to the sub? Four 10"s in a big room like that still isn't all that much really....

 

[Steve81]

The FR is pretty solid being +2/-3db from 16hz to 200, so I don't need any help there, it is just lacking in physical slam/impact a bit.

Is this actual in-room measured data, or are you just going by data-bass figures? If in room, have you investigated what happens to FR as the SPL rises above a base figure?

 

[Hocky]

Where do you cross the speakers to the sub? Four 10"s in a big room like that still isn't all that much really....

80hz

Is this actual in-room measured data, or are you just going by data-bass figures? If in room, have you investigated what happens to FR as the SPL rises above a base figure?

In room measured FR. FR stayed smooth and even to 105db where I stopped going up.

 

[Steve81]

In room measured FR. FR stayed smooth and even to 105db where I stopped going up.

Try pushing them a bit harder. 105dB is just a start when you're looking for serious low end impact. If they pass that test, there are a couple things you can try without shelling a couple grand for more subs, i.e. building risers to enhance tactile feel as well as applying EQ to suit to taste.

 

[Hocky]

A riser for the seating you mean ?

 

[Steve81]

Correct.

 

[herbu]

I would play with your subs positions. Perhaps your seat is in a null. The PB13U is a beast. I have one of them and one Rythmik FV15HP in a room larger than yours. They will knock the breath out of you if I let them. The gain on each is set at about 1/4, just to get them down where I have some adjustment flexibility in my AVR.

Did you rerun Audyssey/YPAO in your new room? You may have to turn up the gain on each sub to get near "Zero" and still allow yourself some "up" potential in your AVR. In other words, settings may not be the same for the same impact in your new room.

 

[WaynePflughaupt]

A map showing the layout of your room and system would be helpful.

Regards,
Wayne A. Pflughaupt

 

[Hocky]

I would play with your subs positions. Perhaps your seat is in a null. The PB13U is a beast. I have one of them and one Rythmik FV15HP in a room larger than yours. They will knock the breath out of you if I let them. The gain on each is set at about 1/4, just to get them down where I have some adjustment flexibility in my AVR.

Did you rerun Audyssey/YPAO in your new room? You may have to turn up the gain on each sub to get near "Zero" and still allow yourself some "up" potential in your AVR. In other words, settings may not be the same for the same impact in your new room.

I'm not in a null - as noted, FR is very good. I didn't save the charts to post, unfortunately. Perhaps of I get time I will measure again.

I will try to post a layout soon.