Interesting observation and question

polkfan38

I have a very small sub from a older HTiB. I want to say it has a 6 inch driver that is downward firing. Anyway, when it is in my upstairs set up, it is on a typical carpeted floor that is hollow. When playing movies with good LFE, it actually does quite well. Getting below 30 Hz anyway. And will put rings in a glass of water on the coffe table! Now, in my basement using the same sub. With a tile floor with cement under that, the bass is not nearly as strong. Room size is almost the same. And so is placement. Is the floor upstairs acting as a passive driver of sorts? I have not gone downstairs to listen to see if there is bass in the basement durring playback.

ROHfan

polkfan38 wrote: »

I have a very small sub from a older HTiB. I want to say it has a 6 inch driver that is downward firing. Anyway, when it is in my upstairs set up, it is on a typical carpeted floor that is hollow. When playing movies with good LFE, it actually does quite well. Getting below 30 Hz anyway. And will put rings in a glass of water on the coffe table! Now, in my basement using the same sub. With a tile floor with cement under that, the bass is not nearly as strong. Room size is almost the same. And so is placement. Is the floor upstairs acting as a passive driver of sorts? I have not gone downstairs to listen to see if there is bass in the basement durring playback.

I'm sure someone more knowledgeable can give you the details but the above scenario sounds reasonable. The hollowed floor upstairs is carrying resonant bass frequencies throughout the room whereas the cement floor has no chamber for resonance. You are actually "feeling" the bass more upstairs because of the conductive nature of the wood floor beams.

Or, I'm completely wrong.

nguyendot

Yeah your other room had more resonance. Not necessarily a good thing. You want to feel the sub, not the stuff the sub is moving.

polkfan38

That's true. But, it is cool that everything shakes a little!
I can't wait to get a real sub however. A PSW505 is looking real good right now!

aboroth00

Cement does not carry resonances well while the hallowed floor carries resonances creating multiple orders of harmonics. So what you're hearing is the harmonics of lower frequencies making it seem that you have a lot of midbass because everything is shaking. A 6" driver will not dig below 30hz with authority nor will a 8" or even 10" in some cases. You can try placing a Subdude from auralex under your sub and it'll tighten up the bass.

polkfan38

Thanks aboroth. I figured somehting with the floor was causing odd harmonics. The sub is actally a neat little machine up to "middle" volumes. Beyond that it looses it's composure. I wish I had the money to get some really good subs. (2) The LFE in some movies really makes me go "ooooooh"!