Ivan Beaver wrote on Tue, 06 June 2006 21:31 |
The price has just gotten out of hand. But I still like the unit. |
Bennett Prescott wrote on Wed, 07 June 2006 05:52 |
Ivan, Tom, thank you very much for weighing in. After having said "it's too expensive" about the last unit I reviewed, I was wary of saying the same thing about this one and was hoping someone would step in and determine value. Those are very much my thoughts exactly... very well put together unit, nice for what it is, I'd love one for taking general purpose measurements... within a few dB is plenty good for what I want it to be. If it were half the price it would still be pretty expensive, however, for what it is. In an age when I can buy a laptop for $100 (thanks, MIT!) that has a high resolution color screen and a powerful built in processor, I just don't see why a handheld piece of hardware like the SP395 can command such a premium in the marketplace. |
Tom Young wrote on Mon, 12 June 2006 17:20 |
Frankly, if their customer service / tech support was better that *might* be enough justification. |
Quote: |
Transmission Loss is used to measure the amount of sound isolation that a partition provides. Typically, a noise source is placed on one side of the partition, and the room noise level is measured in 1/3 octave bands, sometimes at more than one point. Then, the measuring device is moved to the other side of the partition (presumably in another room) and the same measurement is taken. Then, the transmission loss (TL) at each 1/3 octave bands is computed, and a formula is applied to derive a numeric number representing the relative noise reduction of the partition. The idea is that this number can be used to effectively compute the amount of reduction in sound level that a partition (wall) will provide in actual use. There are several ways of measuring transmission loss. One key issue is whether or not the measurement is being done under laboratory conditions, with carefully controlled room reverb time and control of sound leaking around the partition, or whether the measurements are being taken in the field under minimal control characteristics. Several standards apply here, including ASTM 90, which talks about how to measure the transmission loss data, ASTM 413 (or ISO 717-1), to define a laboratory measurement, and ASTM 336, which takes the lab measurement and applies it to field work. The SP495 calculates laboratory values including STC, RW, and OITC. STC (Sound Transmission Class) is the ASTM (US) measurement, RW is based on the European standard, and OITC (Outdoor-Indoor Transmission Class) is based on an A-weighting curve, and is considered by some to be more modern. |