In the interest of simplicity, assume my condominium is basically U shaped. The TV is at the back wall at one tip of the U. The bedrooms are the at the other back of the U, and the guest bathroom is at the apex.
When I’m 8 feet directly in front of my TV at a given volume, it’s quiet and I have troubled making out the dialog. If I move to the bathroom, it sounds much louder. Move further back to the bedrooms, and it’s louder still. This causes problems with my S.O., because if she goes to bed before me, I can’t hear the TV, but she can.
I’m torn between two explanations - resonance, and white noise.
Resonance. If I’m singing in the shower, I sound louder because the sound bounces back toward me. But how could this be the case if I’m in the same room with the source and it sounds louder around a corner? I ponder the complicated Bose speakers in “Wave Radios” and the like, with tubes routing the sound around through curved tubes which effectively increases the fullness and richness of music, but the physics lose me. I mean, there isn’t any energy being added. Is it just the focal point of the waves?
White Noise. There is a lot of white noise in the living room, generated by 6 picture windows, a basically open kitchen with multiple appliances, and a 90 gallon reef aquarium with moving water and fans cooling the metal halide lighting. But if the white noise is high here, and it drowns out the TV in close proximity, why would not the blend of sounds continue around the bends and leave you with the same proportions of white noise to TV chatter in other parts of the house?
This is a very common phenomena with TV speakers. Due to the design of many sets, most sound exits the back of the set. Those little perf. panels in front of the speakers on the front are really poor at passing sound while all the (further away) vent holes on the rear are good at passing sound. To do it right would require quite large openings on the front with more acoustically transparent coverings. Note that which way the driver faces only has a small effect on which way the majority of sound comes from. Some speaker designs take advantage of this and have a large empty space (a la a TV set) behind the drivers and extra openings to reinforce the sound.
I doubt if it’s resonance. Too much other noise in the vicinity is a possibility, but wouldn’t it be just as much of a problem elsewhere? After all, it travels just as the TV noise travels.
How about these possibilities:
1.) focusing. Somehow your apartment is shaped just right to focus the sound waves elsewhere. I’ve heard this phenomenon in museums where there are elliptically-shaped “sound mirrors”. If you go to the focus, you can hear very clearly sounds originating at the other focus. At the Boston Museum of Science they use curved “sound Mirrors” in places like the Communications exhibit to make sure you hear the recording (I’m not sure if the plastic focusing domes are elliptical or parabolic). In both cases, you don’t hear the sound if you aren’t near the focus. Pretty freaky.
2.) Destructive and Constructiver interference. Again, because of the distance and shaping of your apartment, your set and reflections from the walls act like twin orr three sources in a sort of sound version of Youngs’ experiment, where interfering sound waves allow for destructive interference (quiet zones) and constructive interference (loud zones_. I’ve seen (heard?) this effect in laboratories, and I understand they even selling systems for such noise suppression.
Suggestions: To eliminate the effect, in either case, you need to hang things on your walls to minimize reflections and to scramble them. I’m betting your walls are pretty bare. If the effect is due to interference this will make the sound louder in your living room and quiter in the other places. On the other hand, if this is due to focusing, it won’t help you that much in the living room, and it might eliminate the linda neat effect of loud sound in your kitchen.
Do the bedroom and the “tv room” share a wall? If they do, it is possible the wall is simply transmitting the sound and due to silence of the bedroom, it sounds louder in there. For argument’s sake, lets say the U is N-S, and the bedroom and TV room are in the north. Is the bathroom in the north part of the south part of the U? If so, it could again be a wall transmission thing.
It can’t be resonance or interference, because those only occur at specific frequencies. The human voice is made up of many different frequencies; if you just amplify a single narrow bandpass, it would be unintelligible.
I agree with ftg and cmosdes - the TV probably outputs more sound sideways at the shared wall. (Assuming there is one - I got confused with the mention of a “U-shaped” condo, but I took that to mean a single wall within the building divides a rectangular space into a U-shaped cavity.)
There is also the possiblity that the TV is imparting soundwaves directly to the floor and underlying floor joists (solid mediums are more effective in transmitting sound) which run directly from the TV to the bedroom.
If that is the case, you may want to use structural foam coasters or something similar to isolate the sound from the floor.
The walls aren’t bare, to the contrary, one wall is almost completely covered in windows from ceiling to floor (with aluminum blinds), and the rest have rather large paintings in glass frames. That seems to be a pretty effective medium to reflect sound.
There is no shared wall, the guest bedroom is basically in the middle of the U - providing a 15 foot buffer zone between the living room and master bedroom. The guest bathroom is near the apex of the U, slightly around the bend from the living room.
The floor could very well be a contributing factor. We came to inspect the progress while the condo was still under construction, and the floor is concrete, covered in hardwood sheeting. We do have a lot of rather large area rugs, but the TV doesn’t rest on one. I’ll experiment with small pieces of carpet to support the entertainment center.
I’m thinking CalMeachem’s explanation is probably best, given the high reflectivity of the surfaces, and the shape of the condo.
Sounds like focus to me too, like a reflecting telescope. Try to determine the loudest point in the bedroom. Then move the TV and see if that changes the focal point in the other room.
