I was looking at some of the builds and I notice that people put insulation in the risers and sand in the stage why is that, sound residence?

They turn them into bass traps.

even if they're sealed?

They turn them into bass traps.

No, not quite true. Insulation and sand are used to dampen vibration in risers and stages, not to turn them into bass traps. You don't want them resonating, because then your riser and stage become big drums every time the bass kicks in.

-drin

exactly, while you CAN make it in such a way that it becomes a bass trap, the usual reason is to prevent it being a huge drum.

You don't want them resonating, because then your riser and stage become big drums every time the bass kicks in.


I understand we don't want big drum sound, but then why some risers are Helmholtz resonators? I was looking to make mine the way audioholics did their for the tactile effect, hopefully not for it to turn into a drum :eek:

I understand we don't want big drum sound, but then why some risers are Helmholtz resonators?

Because they're designed that way. A Helmholtz resonator is a different animal altogether.

If you want tactile feedback from your riser the simplest thing to do is put a second subwoofer on it. I know McCall has done that with hers and I think she's very happy with it...

-drin

What would be the deciding factors between building a Helmholtz resonator as done by the audiohaulics article vs. just using a second sub on it? Would u-boats we needed if using a second sub?

I understand we don't want big drum sound, but then why some risers are Helmholtz resonators? I was looking to make mine the way audioholics did their for the tactile effect, hopefully not for it to turn into a drum :eek:
I use mine for tactile response. It is stuffed with insulation has bass shakers in it and ONE of my subs ON it. works fabulously well.

Here it is with the bass shakers but before the insulation etc.
http://i204.photobucket.com/albums/bb101/Arwenmark/100_1725.jpg

As I say it was then packed with insulation, except in a channel along the bass shakers. I also left the back corner open.

This is where some of my confusion is coming from. Audiohaulics mention 75% filled but yours and others mentions packed. What really are the determining factors?

This is where some of my confusion is coming from. Audiohaulics mention 75% filled but yours and others mentions packed. What really are the determining factors?

Ok perhaps packed was not the best word, I did fill it to the top and perhaps a bit over the top before the "Lid" went on, except of course I have a channel with NO inusulation running along where those bass shakers are. so maybe it comes out to about 75%. point is you want it to be mostly filled. http://i204.photobucket.com/albums/bb101/Arwenmark/jackwithhat.jpg

thanks. When you said you left the back corner open...what does that mean and what pros or cons results?

Also, is there any concern with the fiberglass leaking out?

thanks. When you said you left the back corner open...what does that mean and what pros or cons results?

Also, is there any concern with the fiberglass leaking out?

Well in my case the back corner of the riser is basically missing that is there is a section about 2x2.5' cut out, so instead of sealing this up with solid "walls" I left it just covered with fabric to make it look better and keep stuff from getting in or out. The effect has been that it seems to act as a sort of a bass trap, which is great. I did not plan it to do that but it seems to have, since I tried last week putting something solid over the open portions and there was a huge difference.

I know Dennis Erskine has posted about leaving some cut outs on the top of the back though I don't have that link handy. Anyway I needed the cut out there and so it has worked nicely for me.

With the bass shakers, do you have to run each bass shaker back to your subwoofer out jack on the receiver or do they connect to a hub or something and then it connects to the subwoofer out jack? Also, would you want/need bass shakers AND a dedicated subwoofer?

Shakers are usually run with their own amp. So you split the LFE signal and run it to the shaker amp and sub.

With the bass shakers, do you have to run each bass shaker back to your subwoofer out jack on the receiver or do they connect to a hub or something and then it connects to the subwoofer out jack? Also, would you want/need bass shakers AND a dedicated subwoofer?

I think depending on the ohms, you can wire these in a parallel and/or serial configuration to its own amp to keep the ohms rating to 4. Not sure where I say a diagram of this before.

There are several wiring diagrams in the archives in the Subwoofers, Bass and Transducer forum. Also Parts Express has this info on their site or they did, and if you call they are very knowledgeable about them.