The source of a mysterious hum in Ranchlands remains a mystery.

Some residents of the northwest Calgary neighbourhood say the noise has been bothering them for more than two years.

The Calgary Eyeopener's David Gray talked to Marcia Epstein on Thursday morning about the buzz.

Epstein is an acoustic ecologist at the University of Calgary and is part of the Ranchlands Noise Investigation Team. The team met with Ranchlands residents Wednesday night to update the team's progress in pinpointing what is making the noise.

David Gray: Remind us, if you can, how residents have been describing the noise?

Marcia Epstein: Most describe it as literally a hum, a "eeeeeeeeeeeeeeeeeeee" sort of sound. Sometimes, apparently, it gets quite a bit louder and sounds more like a jet engine revving up or idling from far away.

DG: That’s a remarkable sound. We’ve heard about this for years now, but then we always have some people who say, ‘I’ve lived there forever, I’ve never heard it.’ Now, you’re an acoustic ecologist, it’s your job to hear sounds outside — have you heard it?

'We know that the sound is happening and there’s quite a variation in who hears it. We think it’s anywhere from 12 to 20 per cent of the community that’s affected.'Marcia Epstein, Acoustic ecologist, part of the Ranchlands Noise Investigation Team

ME: I have, actually. The sound is real, we have measurements of it. I’m working with an acoustics engineer, who has all the equipment for recording mysterious sounds — or at least, the ones that aren’t too mysterious — and he has hours and hours of recording, so we know that the sound is happening and there’s quite a variation in who hears it. We think it’s anywhere from 12 to 20 per cent of the community that’s affected.

DG: And now, is that because of where they live, or how sensitive their ears are?

ME: At this point, we’re thinking it's probably sensitivity, but it may also be the location of their houses. Because our best guess so far — when we’ve eliminated quite a few things that it isn’t — our best guess is that it’s something that’s coming through the frames of the houses from underground. And it could be the water system. We’re still in the process of checking that out. It’s a slow process.

DG: There was a theory, a popular theory, that it was the Bearspaw water station, have you ruled that out?

ME: We have not found a pattern of correlation, between the frequencies that we’re measuring and the output from the water station at Bearspaw. But, there are some other water stations closer to the Ranchlands. You know, smaller stations that act as, kind of, relays, and we still have to check those.

DG: Another theory, there’s lots of them, but another theory I heard was that there was a possibility that it was some kind of electromagnetic frequency from a cellphone station interacting with other frequencies, have you looked into that?

ME: We are starting into the process of looking into that. It’s more difficult to do because measurement is very challenging. What we suspect is that for some people there may be a reaction to those frequencies which are not audible — they’re too high. They may be setting off the auditory nerve in some way and there’s already documentation in the medical literature about that. Some people are sensitive to electr magnetic frequencies. So we’re looking at a combination of location, maybe the geology of the area, which is still an open question, we need to get data about that.

DG: Is there anything unique of the geology in the Ranchlands area, that you know of?

ME: We don’t know  yet, we’re still looking into that. And the third factor is people’s sensitivity to hearing which is tremendously variable.

DG: It certainly is. I understand that, but you’ve heard it, is your hearing particularly sensitive?

ME: Well, I’m a musician, so it might be. I don’t think it’s abnormally sensitive.

DG: As a musician, any idea what note? Is it an A? Is it an E? Is it a B?

ME: It’s not always the same thing, we’re getting a concentration of frequencies around 40 hertz, and 40 cycles per second.

DG: You know, I’m listening to you talk about this, it must be really frusturating not being able to figure this out. Am I hearing that right in your voice?

ME: It is! Yes, well when we started we were expecting it would take maybe a year to figure this out and it’s been over two, largely because the research team consists of volunteers. We don’t have funding, we don’t have support from anywhere, so we have to work in this in our spare time, basically. There are little bursts of activity and ten months go by when nobody has time to do anything or we’re waiting for information from the city or the water system, or whatever’s going on, so we’re glad to accept offers of help from the community.

DG: Now, while you’re trying to figure out what it is, and what’s causing the sound, there are others that are thinking, ‘Heck, I don’t care what’s making the noise, let’s just stop it.' Tell me about the noise cancellation project that’s being worked on for people who live there.

ME: The engineering faculty at the University [of Calgary] is getting interested in this. Michael Smith, who is part of the faculty there, is looking into how the noise could be cancelled out by some device that people could keep in their homes and he has assigned one of  his graduate students to work on it.