Enhancing existing corners

[Dylanl]

Has anyone ever beefed up the existing corners in a room to see if performance on Klipschorns would increase? The reason I ask is that my current walls (corners) actually vibrate from the bass coming out of my horns. This has to be a loss in the speakers output. My walls are on 16" centers 2x4 with 4" of insulation & 1/2" drywall. What if I removed the 1/2 drywall, braced the existing studs, added a few more studs out to 4'away from the corner & finally replaced the existing drywall with 1/4 MDF board and covered it with 1/4 drywall. Do you feel the bass would be better?

[artto]

There is nothing you can do about the vibration except to try and minimize it. My Khorns are, literally, secured to the foundation of the house, and the walls are heavily reinforced and braced tightly against the foundation. See my thread in the Architectural topic area for a full construction description.

It doesn't improve performance much per se'. Mainly it stops the walls from acting as passive radiators. I think whats important is observing the minimum distance of 4' from the mouth of the Khorn, getting a good tight corner fit, etc. Securing them to the foundation didn't even improve bass performance as much as it did mid/treble performance.

[Dylanl]

So are you saying this would be a good thing to do? It would not be that much work for me to do. I also feel like the floor to my upstairs rooms are moving from the bass in the game room where the horns are. You can not feel it downstairs as well as you can upstairs. Odd huh??

[Dylanl]

Anyone there?

[neomartic]

I have no architectural advice, but I'd say your system is just too sweet and I'd be more worried about your house falling down!

[D-MAN]

Whenever I hear someone with Khorns asking what they can do to get more bass response, I always think "room treatment", as Khorns really put out the bass. The problem is just that it ain't getting to full bloom.

So you are already on exactly the right track. I would start to look for modal cancellation effects in the room. Solving those issues is easier to do than rebuilding a corner, I should think. At least, it should be done first, IMO.

DM

[Dylanl]

D-MAN you should feel my wall shake even at moderate levels. That is why my thinking is heading toward re-enforcement. I know it was mentioned somewhere before, but there is a good book that Artto was pimpimg on room acoustics. Does anyone know the name of it and where I can buy it?

[DAX616]

try this http://www.auralex.com/referrals/default.asp I believe its the master handbook of accoustics. I'm no expert but I have the same problem. I am in the process of bricking the corners to the ceiling. The corners will be isolated except from the slab and some points that hold the brick while its drying. I would agree that bass trapping is probably your first choice.

[artto]

Bass trapping will not reduce vibration in the walls induced by the Khorn. What it will (should) do is even out the peaks and dips in the low frequency response caused by room modes, making the apparent bass sound louder and deeper, which may give you the inclination to not, turn things up as loud, which in turn may reduce structural vibration.

As far as strengthening the wall corners is concerned, I dont think it improves the actual performance of the Klipschorn much, per se. What I think it does do, is reduce the potential effects of the vibrating room surfaces contributing to producing sound, in much the same way a passive radiator does, although in this case its not controlled, and therefore may result in coloration of the sound. You can hear this effect by simply having a second set of unused speakers in the room. Linn Products (UK) demonstrated and brought this to the audiophile communities attention well over two decades ago. Its also one of the reasons speakers sound relatively bad in dealer showrooms. When the room is loaded with many speakers, their cones/driver surfaces are set into motion from the SPL produced by the operating speakers.

Reinforcing the room corners for the Khorns will not stop the vibration from traveling to other parts of the house where the lower frequencies are seemingly louder than they are in the listening room. This is simply because the low frequencies have much longer wavelengths, and therefore can travel greater distances, especially through hard, dense, structurally connected surfaces, while the shorter mid/treble wavelengths are substantially attenuated before getting to those other parts of the house making the apparent bass seem louder in those locations. In fact, making the structure and its connections stronger, can actually make the sound transmission more audible in other locations of the building, or even nearby buildings/structures.

Sound transmission/isolation, low frequency response anomalies caused by room modes, and the potential sound coloration caused by vibrating room surfaces and other objects in the room, are all different things and need to be treated differently. For the record, many recording studios and fine auditoriums/concert halls, are actually a room within a room, acoustically and structurally isolated from each other, and in extreme installations, isolated from the earth itself.

The book Ive referred to is Master Handbook of Acoustics by F. Alton Everest. Its available from Amazon.com and most major booksellers. Some feel its a little too technical, but this is about as basic as it gets without stepping into the professional realm. But dont forget, no one learned any of this stuff overnight. Hell, even myself, after years of studying and planning my listening room, pulled a mini Lincoln Center. (Lincoln Center/Avery Fisher Hall was notorious for being touted as one of the finest acoustic halls ever built before it was completed, only to be completely gutted and underwent acoustical reconstruction years later because it was designed so wrong. Ironically, the architect, Max Abramovitz, later designed my favorite concert hall, the Follinger Great Hall, albeit this time with assistance from the great acoustician, Cyril Harris, who btw, also did the acoustical reconstruction on Avery Fisher Hall).