Sonics of Soundlabs

You are speaking about standing waves, which is different than room gain. Room gain results from the maximum length of the wavelength being longer than the room. You do not have standing waves at frequencies below this fundamental frequency, only above. The way to compute the lowest resonant frequency of the room it to take 1127 (or if metric 343) divided by (longest room dimension x2). The result is the lowest freqency that you can have a standing wave and the knee freqeuncy below which you experience room gain.

You analogy of an organ pipe is incorrect as an organ depends on resonance to produce sound. This is far different than sitting in an enclosed area (a room) with a device that puts out an accoustic signal.

Here is a quote from Tom Noussaine on the subject:

"2. Room gain: Room gain starts at roughly the frequency of your lowest axial mode. The pressure gain is 12 dB per octave as frequency falls. In a car its at 60-70 hz depending on size. In my 2136 cubic foot older listening room it started at just below 30 Hz. In my 7500 cubic foot current room it starts at 16 Hz. A Velodyne FSR-15 had 8 dB less output at 2 meters in the larger room with idntical placement."

http://archive.avsforum.com/avs-vb/history/topic/39249-1.html

You guys have it backwards concerning room size. Once you get a wavelength that is longer than the room, you get what is termed room gain, on the order of 12db/per octave. (In an actual room it is less due to the walls flexing and losses through the walls, but the gain is there). Smaller rooms = more bass.

I will try this one last time and then quit wasting my time, as it appears you are more concerned with running your mouth than hearing the truth. Below the resonate frequency of the room, there is what is termed transfer function gain, room gain, or cabin gain. All are the same thing. Below the knee frequency, there are no standing waves, only the 12db/octave rise.

Try this little experement. Take your subwoofer, run a 20hz signal through it. Measure the output at 10 different locations in your listening room with an SPL meter. Don't change any levels and take that subwoofer and put it in a closet with a door. Close the door and stand in there with the sub. Measure the SPL reading there in 10 different locations. Guess what the SPL reading is higher and very close all around. Can't find any standing waves, because there are none.

Now, I know you think you are smarter than Tom Nussane, so here are a few more links that discuss the transfer function, but I will guess that you will continue to argue until you are blue in the face that you are right and scientific fact is wrong.

http://www.linkwitzlab.com/rooms.htm#Standing%20waves

http://www.linkwitzlab.com/thor-intro.htm

http://www.linkwitzlab.com/images/graphics/enclosure-spl.gif

http://www.caraudiohelp.com/newsletter/cabin_gain.htm

Boy you really don't get it!!!!! There are no standing waves below the lowest nodal frequency. Period, it doesn't matter what type of tranducer you are using. Also, you don't measure the diagonal of the room, you measure the longest distance between two walls. Nodes and suckout are caused by reflections of parallel walls, one reason you will see that studios use stacked or even angled walls is to spread out these modal frequencies.

Read and re-read the quote you posted (as apparently you know believe in room gain since Linquist addresses the subject). It clearly states "Room modes cannot exist when 1/2 of a sound wavelength exceeds the longest room dimension." No ifs ands or buts. Below this frequency you may or may not have gain depending on the type of radiator used, but you will not have room related roll off or standing waves.

You are correct on one point (so apparently you did read the article, even if you choose to only accept parts of it). Below the lowest modal frequency a dipolar may or may not cause room gain. This is because room gain is triggered by pressurazation, which a dipolar does not normally cause.