davis_square | Red Line noise levels (Reply)

To follow up on a previous thread that discussed noise levels on the Red Line on this side of the river, I've had to take the T a few times since then (mostly I bike), and I brought along my sound meter. Some rambling and some numbers after the cut...

The ambient noise level at Davis on the platform is about 60dB, with announcements going up to 80dB, at least if you're standing in the right spot.
Trains arriving and departing take the noise up to 95dB, and they idle at about 80dB.

There's a great variety in noise levels at various points between the stations. I've really only written down the peaks, some of which only last for a few seconds.
I'd need more patience and/or different equipment to really track how loud things are for extended periods of time.
In general, the 018xx series of cars are definitely quieter (inside) than the 017xx, 016xx and 015xx ones. By about 5dB.

There's a huge variation in noise levels based on how fast the train is moving. This difference seems to overwhelm pretty much anything else (number of passengers dampening the sound, and even old/new car models).

I really don't have enough raw data (well, 6 trips inbound, 4 outbound) to say much, given the variety of trainsets.

In general, however, peaks between the stations I travel on are all around 89dB to 91dB or so. I go between Davis and Kendall generally (and lately into Boston, too, but after Kendall, the noise level drops dramatically, both due to reduced speed and increased outside-ness, no doubt). I have no idea what things are like between Davis and Alewife.
I did go on one rather overwhelmingly louder trainset, I think it might have been 01700, that consistently peaked around 95dB between every station.

Both inbound and outbound, the stretch between Porter and Harvard seems to be the loudest (probably because of the max speeds and/or the squealing right by Harvard), but not by all that much.
Then again, it's hard to have any kind of conversation in the high 80s.

For the record, this is all measured on a Radio Shack Analog Sound Meter (currently available there for about $45... not sure what I paid for it when I bought it a number of years ago, probably something similar), set to "Slow" response and "A" weighting settings, in case you know/care what that means.

Hope this wasn't too much of a ramble.
If anyone wants to take more careful notes, I'd be willing to lend them my sound meter. I don't take the T often enough, but maybe someone else is obsessive enough to get all detailed about it and post their results more coherently.