the Jon Risch site is very good for these. However, you do need to make a bunch of them. When room modes are excited a few placed in the corners will not make a very big difference. I often hear people tell me--these traps don't work. Well, they do, but room modes are compounded by the surface area of wall(s) and thus need a large portion of the wall covered to relieve the pressure that is causing the problem.
Showing 2 responses by rives
Redwoodgarden: You are correct. My order of best possible scenarios are as follows: 1. A room with good modal spacing--thus no prominent modes to create a problem. No need for traps, resonators, or electrical correction. 2. A room with a built in Helmhotz resonator that is specifically tuned to the right frequency (this is far more difficult to do than most people would imagine and can actually create a new set of resonance problems that most people don't even recognize--but if done correctly it works very well). 3. An analog parametric compensation device that can very specifically tune to the problem frequency(s) and not corrupt other parts of the signal. This is exactly why we designed the PARC. 4. Broadband attenuation through a pressure relief (bass traps). This can work if the problem is not very severe and is naturally a low Q factor (broad band). It does not work well if it is a high Q factor and needs high attenuation. Hihg Q > 2.5 and high attenuation would be > 5 dB. We designed the PARC because most rooms are not designed with proper modal spacing and have bass boom. It quickly becomes the only practical way to deal with the problem. We also spent a tremendous amount of time insuring that it was transparent and did not cloud the signal in any way. If anyone heard the demonstrations we had at CES it was remarkable and I'm very pleased both with the results we achieved and with the response we got. It is a fully progammable unit that can adjust the frequency, Q (width of attenutation), and amount of attenution. You can read more about it at PARC |