What to record in a 2-mile tunnel.


I just got back from a trip where there was a 2-mile long railroad tunnel which part of a railroad track that was later made into a mountain-bike trail.

Needless to say I brought my recording equipment just for fun.

I get to the middle of the tunnel, the echo is about 15 seconds long and it's pretty silent in there bar a few distant trickles of water which you can eliminate by finding a dry spot in the tunnel.

I didn't have a project which needed this type of echo but what sort of generic things would you guys get if you had that opportunity?

I got some good bangs and impacts with the verb that sound great - actually they sound AWESOME when down-pitched,

but what sorts of other stuff would you guys try or record while down a 2-mile stretch of abandoned railway tunnel?

It sounded amazing and I have never really heard anything like it. Great experience if you ever get the chance.

  • Ryan


Posted 2010-08-06T02:15:10.230

Reputation: 14 155

1better question is…what NOT to record?! – Jay Jennings – 2010-08-06T02:42:44.943

1Definitely. Take as much noise-making gadgetry in there as you can and record it all. Also this might be kind of random, but I think it would be funny to record yourself urinating with all of the echo. Especially a really long one, it would sound like the longest pee ever. You could fake it in various ways.. – bpert – 2010-08-06T02:48:50.917

@birdhousesound Yeah, you're right.. It sounded so great I can't describe it. You had to be there. @bpert Hah! – Utopia – 2010-08-06T03:22:39.730

Defintely jealous..care to share any of those sounds?? – Chris – 2010-08-06T04:48:44.020

1better yet, care to share the location? – Steve Urban – 2010-08-06T15:17:07.693

Better yet, need any coffee? – Chris – 2010-08-06T21:01:04.490

Hiawatha Trail. – Utopia – 2010-08-07T21:07:24.713



Among many other things, I'd record a swept sine wave from various distances for impulse responses.

Jay Jennings

Posted 2010-08-06T02:15:10.230

Reputation: 15 432

See, I would have done this but didn't know how and when I got told "we'll be going through this tunnel" it was too late to gear up for it... Next time... Very good idea. – Utopia – 2010-08-06T03:35:13.173

Altiverb makes it pretty easy to shoot an IR. They provide a set of sweeps that you can download and play on location through powered speakers / boom box / whatever, and then later you can take your recordings and process them through what they call the IR Pre Processor. And when it's all said and done, you should have an IR ready to go! Your mileage may vary… – Jay Jennings – 2010-08-06T05:00:24.030

An IR was the first thing I thought of when I read this. I thought that I had read somewhere that alternatively to the sine sweep though you could use a starter pistol. Is that true? I would imagine it wouldn't offer the rich tonalities that a full range sweep would. – Steve Urban – 2010-08-06T15:07:28.433

@Steve, you're correct in that you can use a starter pistol to excite the ambience around you, but you won't get the full frequency range as you would from a 20Hz-20kHz sine wave sweep. – Jay Jennings – 2010-08-06T21:37:08.080

The frequency response of a sine sweep will be limited to whatever your speaker can reproduce. An impulsive noise like a pistol or spark should get a better frequency response, but the signal-to-noise ratio will be worse than a sweep. – endolith – 2010-08-06T23:11:06.377

disagree with @endolith, I don't believe a starter pistol will excite the lower frequencies as efficiently as a clean sine tone. Of course it depends on what speaker you play through (ie. boom box won't reproduce 20Hz-20kHz) but if you really do it right you can bring professional powered speakers that will get darn close. Not only that, but you can use longer sweeps that will do a better job of exciting the space, as opposed to a pistol that is a transient event. – Jay Jennings – 2010-08-07T00:01:59.857


You could get some good atmospheric scary monster screams, stand really far away from the microphones and try to make disturbing freakish vocal sounds (and hope there arent any other people nearby).

Haydn Payne

Posted 2010-08-06T02:15:10.230

Reputation: 1 150

Thanks! Yeah - I thought of that but there are children and families in there and I'm sure I'd be heard all the way down the tunnel. I'll try it next time, though. – Utopia – 2010-08-06T16:44:49.363

This would be perfect for worldizing, similar to the balrog in LotR. – Dave Matney – 2011-03-21T16:54:22.657


Along with re-recording a sine sweep to also try worldizing textures and toens in there... I spent some time in Taya Caverns, about an hour out of Tokyo. The caves were created by Buddhist monks and there were chambers where they would go & meditate & chant. When I was in there I noticed how resonant the chambers were at vocal frequencies - drones would sound so incredibly rich in there!!! Take a guitar amp, guitar and ebow?


Posted 2010-08-06T02:15:10.230


I was thinking drones would be a good idea too, no point in putting up an extra answer saying the same thing, so I'll just +1 you here. – Shaun Farley – 2010-08-06T13:09:05.603

Cool! I'll check it out. Mind you I've only got a mountain bike but maybe I can get one of those trailer things to hitch onto a mountain bike. I couldn't imagine riding a bike while carrying a genelec speaker on a rocky trail. Haha. – Utopia – 2010-08-06T16:45:59.797


Also consider materials. Rocks (small and large), glass (thick and thin, hits and breaks), rubber balls, balloon pops, and so forth. Anything bowed in there will be huge! Try a whole passel o' mic placements, too, to see if you can find some super-bassy corners or bright reflections. I've done this with a local cow tunnel which, while not very long, has a square cross-section, which creates a huge trail of slapback goodness.

Have fun!


Posted 2010-08-06T02:15:10.230

Reputation: 11 088

Thanks! I definitely had to fool around with mic placement. I noticed that someone talking toward you you could hear easily, but when he turned around and talked down the tunnel I could barely hear him. Weird phenomenon. – Utopia – 2010-08-06T18:53:36.440