Question about "ringing" sound from IB

[Darren]

I've noticed in different seating positions in my room during many movies the explosions or thuds have a ringing sound, like a tone or bell sound where my box sub reproduces it as a rumble or thud as it should be. In the listening position the IB sound great and this ringing sound isn't aparent. It sounds more accurate. Is this just the room amplifing certain frequencies in the different locations? My box sub is failry consistent around the room where the IB is very different in certain areas.

What could this be? It is quite disturbing because it doesn't sound natural at all... it sounds artificial or colored. I'd like to eliminate the ringing in certain seating positions but I'm not sure where to start.

Any ideas?

[ThomasW]

Room modes....

www.mcsquared.com/modecalc.htm

Bass traps will help with that....

[Darren]

Ah yes, back to the bass traps

I'm just surprised it doesn't seem to happen with the box sub... maybe it is just not as noticeable. I'll read up on the link.

[chrisbee]

My guess would be that the IB produces clean and powerful LF fundamentals with little harmonic distortion.

The box sub produces a mass of harmonics on everything it plays.

The room can ring clearly on certain clean low frequency tones or narrow groups of tones from the IB. Enough to catch your attention.

The hash coming from the box sub doesn't offer any particular frequency for the room to pick up on specifically to produce ringing.

Well, I said it was a guess.

This sounds like your room is completely empty of any absorbent material. Ringing is the sort of thing you notice when you look round an empty house or apartment when house hunting.

Though obvious ringing is usually at a higher frequency than a sub usually plays at. It can sometimes be excited by a deep male voice when standing in a particular place in the room. You suddenly hear your own voice amplified. The introduction of normal furniture and furnishing materials usually kills obvious ringing by "diluting" the area of parallel surfaces that form these standing waves .

Remember that it only matters if you can hear it at your normal seating position. If it is inaudible elsewhere then you can hopefully ignore it.