Newbie question re: Sub choice for poorly constructed California house.

[tman]

Looking for input on subwoofer.

I live in Silicon Valley and my house is old, I think poorly constructed, sitting on clay. Shutting the front door makes the walls shake a little. Big truck going by makes the house shake a little. House is structurally sound, but no insulation, no plywood sheeting.

I'm not going to add insulation or plywooding for several years since stucco is good and wiring is old.

I'm choosing Hsu VTF3 Mk3 and the SVS PB12 Plus that's on sale. I want to hear movie soundtrack, not the house. I will not play sub at crazy loud volumes.

My floor standers go to low 40's, high 30's in my room and nothing shakes even at loud volume.

Does it matter which sub I get from standpoint of house shaking? VTF3 high output gives <25Hz extension, PB12 Plus high output gives <20Hz. For my case should I go for the VTF3?

Also, if I was having shaking, would a 20Hz or 30Hz FMOD high pass filter be able to help without hurting anything?

Any quick simple things I should be doing to tighten up the house for compatibility with a decent sub?

Thanks!

 

[agarwalro]

Does it matter which sub I get from standpoint of house shaking? VTF3 high output gives <25Hz extension, PB12 Plus high output gives <20Hz. For my case should I go for the VTF3?

Also, if I was having shaking, would a 20Hz or 30Hz FMOD high pass filter be able to help without hurting anything?

Any quick simple things I should be doing to tighten up the house for compatibility with a decent sub?

Thanks!

If you don't like your floor and walls shaking, maybe a sub is not what you want . On a serious note, try a tactile transducer like the Buttkicker, it will attach to your furnature and should have minimal to no effect on the structure.

Different brands of subs will have no effect on the shaking since a specific frequency at specific volume (say, 20Hz at 75dB) from any sub will be the same and have the same effect on the structure.

Different parts of the structure will have different resonant frequencies, so your floor might shake at 15Hz and the walls may shake at 40Hz. Adding a high pass filter will definitely help at the expense of reducing the effectiveness of the sub and its effectiveness in reducing shaking is questionable. Not to mention that, if your speakers go down to 40Hz and you high pass your sub at 30Hz you are not gaining much from the sub and there is no point getting one.

A properly placed sub with calibration for volume will help minimize the structural shaking. You can place a speaker riser (a heavy foam pad to elevate the sub 2-3 inches off the floor) under the sub to reduce sound transmission to the floor.

 

[tman]

Thanks Agarwaldo!

Thanks,

Very good tips. Greatly appreciate. Will help me alot.

The reason I'm considering FMOD for 30Hz+ or 20Hz+ even though I have floorstanders that go down to low 40Hz, is I have to replace them with bookshelf's to fit a 46" flat panel display in my aforementioned Silicon Valley home. My whole 4 bed/2bath house is 1350 sq ft. Ahh, California... Gotta love it.

My new speakers will need to cross-over between 60 and 80Hz and I have to fill an 18'x38'X8' volume. I was curious about SVS PB-12 Plus vs. Hsu VTF-3 because many people post that they are equivalent subs and so with PB-12 on sale, one should decide whether the finish is worth $100 extra. However, port tuning seems to be different. With Hsu it seems you can block 1 4" PORT to tune for 25Hz extension with higher SPL, while in case of SVS you can tune for 20Hz, 18Hz, or 16Hz depending on how many of the 3" PORTS you cover up. I wasn't sure if it was clearly understood what frequencies floor or wall systems are typically sympathetic to, whether if I only care about high SPL at >25Hz the Hsu is better choice. With tax and shipping there is very little difference between Hsu and SVS.

 

[annunaki]

Thanks,

Very good tips. Greatly appreciate. Will help me alot.

The reason I'm considering FMOD for 30Hz+ or 20Hz+ even though I have floorstanders that go down to low 40Hz, is I have to replace them with bookshelf's to fit a 46" flat panel display in my aforementioned Silicon Valley home. My whole 4 bed/2bath house is 1350 sq ft. Ahh, California... Gotta love it.

My new speakers will need to cross-over between 60 and 80Hz and I have to fill an 18'x38'X8' volume. I was curious about SVS PB-12 Plus vs. Hsu VTF-3 because many people post that they are equivalent subs and so with PB-12 on sale, one should decide whether the finish is worth $100 extra. However, port tuning seems to be different. With Hsu it seems you can block 1 4" PORT to tune for 25Hz extension with higher SPL, while in case of SVS you can tune for 20Hz, 18Hz, or 16Hz depending on how many of the 3" PORTS you cover up. I wasn't sure if it was clearly understood what frequencies floor or wall systems are typically sympathetic to, whether if I only care about high SPL at >25Hz the Hsu is better choice. With tax and shipping there is very little difference between Hsu and SVS.

That is a big room. Over 5,000 cu.ft. I would do the SVS as it allows more tuning options. Not to mention in 20hz tune will allow more port area than the HSU in 18hz tune allowing higher SPL potential. It will have 21.21 sq.in. of port area vs. 12.59 sq. in. both with a 12" woofer. Essentially the SVS will move more air. With both ports open on the HSU it will have a tuning of 25hz and only 3.97 sq.in. more port area than the SVS. To me the advantage goes to SVS here again because all ports open on the SVS will play 5hz deeper, or more, than the HSU. The HSU would have a very slight spl advantage (inaudible) over the SVS but would be at a significant disadvantge in low end response.

Using a 20hz highpass FMOD coupled with the 20hz native tuning on the svs would yield a 36db/oct. rolloff at 20hz. and more because the SVS has a selectable built in infrasonic filter at the tuning frequency. In reality the FMOD is not necessary but could be used to steepen the rolloff at the tuning frequency.

 

[annunaki]

Tuning on the HSU works the same way as the SVS plugging a port yields a lower tune. The SVS having three ports allows more tuning options than the HSU. It also allows a lower native tuning frequency (i.e. all ports open) of 20hz. Like stated above this allows a significant port area advantage (for the SVS) when the HSU is tuned to 18hz. 21.21 sq.in. for the SVS > 12.59 sq.in. for the HSU