[BradJudy]

I'm not sure.  The box is 100% vibration free when playing even at very loud SPLs, so I'm not sure that the vibration in the floor is being transferred from the box to the floor. 

Good point.  My Titan is low vibration too (although probably not as much as the one you've built). 

[TRADERXFAN]

Here's what I posted on AVSforum last week.

Well, I spent some time with ETF today and my room has a huge spike (like 12db+) at 50Hz.  I messed with the parametric EQ in my Pioneer Elite for both the main channels and the sub, then messed with the single band parametric EQ on the sub.  It blends better now, but the room definitely needs some room treatments.  Being that it's also our home office / library I'm not sure how crazy I can go on the treatments.

I also think some of my feeling that it's not blending well is from the vibrations in the floor.  Sound travels faster in wood than air, and I swear the vibrations my feet feel are tell my brain the bass is arriving out of sync with the mains. :eek:

I've spend some additional time with them since them.  It seems to blend into the system pretty well now.  I plan to make some OC703 (or similar) traps and put them in the front corners of the room to start with and see where I need to go from there.  I suspect I will need to add an outboard EQ for the sub like I have in my great room, but we'll see.

Front of the room: (pardon the mess)

I have read from Geddes that the ear takes a few cycles for  you to actually "hear" bass, so that is more likely the difference. You can feel it in your feet before you perceive it audibly.  If not, I think you would have to be at the other end of a huge room to really have any chance of a significant difference in time arrival.  I bet is something to do with re-radiation off of the structure, like the floor and walls vibrating. If so, you probably should damp the room structurally (double drywall with CLD) to really tame this kind of issue.   Fiberglass absorbers, etc, would have minimal effect at deep bass frequencies.

Tony

[KS]

I suspect I will need to add an outboard EQ for the sub like I have in my great room, but we'll see.

Won't the controls on the servo amp handle your EQ needs?

Could the sound through the air be exciting the wood floor?  Would a mass loaded acoustical barrier in a floor reconstruction help?
http://www.silentsource.com/barriers-soundbarriers.html
http://www.soundproofing-acoustical-solutions.com/tuff-mass-barrier.html

[Stereodude]

I have read from Geddes that the ear takes a few cycles for  you to actually "hear" bass, so that is more likely the difference. You can feel it in your feet before you perceive it audibly.  If not, I think you would have to be at the other end of a huge room to really have any chance of a significant difference in time arrival.  I bet is something to do with re-radiation off of the structure, like the floor and walls vibrating. If so, you probably should damp the room structurally (double drywall with CLD) to really tame this kind of issue.   Fiberglass absorbers, etc, would have minimal effect at deep bass frequencies.

Tony

The room treatments I'm looking at are to tame the audible acoustic problems, not fix any vibration issues.

[Stereodude]

Won't the controls on the servo amp handle your EQ needs?

Could the sound through the air be exciting the wood floor?  Would a mass loaded acoustical barrier in a floor reconstruction help?
http://www.silentsource.com/barriers-soundbarriers.html
http://www.soundproofing-acoustical-solutions.com/tuff-mass-barrier.html

A single band parametric EQ is fairly limited in capability.  An outboard EQ will allow for much more control of the bass.  I'm using a Behringer DSP1124 in my great room for a sub EQ and it works quite well.  After some room treatments I will remeasure and see if I need to add one to this system.

Regarding the mass loaded acoustic barrier...  Various modifications to the room's construction might help, but at this point my library / office is not intended to be a super serious 2 channel listening room, so I'm just not willing to go that far.