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Easy way to stop an echo in a large room? [message #86616]

Tue, 21 November 2017 08:26

Lost the Remote
Messages: 145
Registered: June 2017

Master

We're rehearsing for Christmas programs already. The building used to be a community center, but it's not been in use regularly for years due to lack of funding. Some of the kids are complaining about the echo because it makes it harder to hear themselves sing, play their instruments, or listen to the music. The building is made of concrete and tile. The room itself is large and empty. Do you believe just adding chairs and some Christmas decorations will help with the echo issue?

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Re: Easy way to stop an echo in a large room? [message #86618 is a reply to message #86616]

Tue, 21 November 2017 09:08

Wayne Parham
Messages: 18792
Registered: January 2001

Illuminati (33rd Degree)

Add lots of absorbent material and furniture. Carpeting, pads on the walls, anything that can absorb and damp the sound.

The most effective position for dampers is a few feet from the walls. So a thick sheet hanging in front of a wall is better than the same sheet attached to the wall.

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Re: Easy way to stop an echo in a large room? [message #86654 is a reply to message #86618]

Sun, 26 November 2017 16:56

Lost the Remote
Messages: 145
Registered: June 2017

Master

Thanks for replying, Wayne, you gave me a lot to work with and the improvements have helped. I didn't realize that dampeners weren't meant to go right on the wall, but that makes sense. So far, I've added furniture and a large rug that covers a great deal of the room which has helped. I'll add the dampeners next. I just need to find a way to make it all look cute. Guess I'd better head to Pinterest.

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Re: Easy way to stop an echo in a large room? [message #87314 is a reply to message #86618]

Thu, 01 March 2018 11:29

EasyE
Messages: 16
Registered: March 2018

Chancellor

Wayne Parham wrote on Tue, 21 November 2017 09:08

Out of curiosity, why does that extra few feet between the wall and the sheet make a difference? Would the sheets need to cover the entire height of the wall?

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Re: Easy way to stop an echo in a large room? [message #87315 is a reply to message #87314]

Thu, 01 March 2018 11:52

Wayne Parham
Messages: 18792
Registered: January 2001

Illuminati (33rd Degree)

The most effective place to put a damper is 1/4λ or an odd-multiple from the sound source or reflector. So that means 1/4λ, 3/4λ, 5/4λ, etc. These are positions where the acoustic energy is greatest, so that's where you want to place the absorber.

While the 1/4λ distance is frequency-dependent, all frequencies require some distance for wavefront expansion. So while high-frequencies have shorter wavelengths, you can still trap them at distant odd-multiples. Lower frequencies, on the other hand have longer wavelengths so their 1/4λ nodes are further away.

So if you want to damp sound down into the vocal range, your best absorbers are either very thick or spaced away from the walls or both.

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Re: Easy way to stop an echo in a large room? [message #88536 is a reply to message #86616]

Fri, 27 July 2018 21:22

Jazzy
Messages: 78
Registered: June 2018

Viscount

Are there instruments that produce more echo than others? I'm boggled by the frequency explanation and I'm wondering whether a Bass has a lower chance to echo that much compared to a violin.

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Re: Easy way to stop an echo in a large room? [message #88544 is a reply to message #88536]

Sat, 28 July 2018 08:42

Wayne Parham
Messages: 18792
Registered: January 2001

Illuminati (33rd Degree)

Echo is caused by the environment, not the source. That said, the amount of reflection can certainly be different at higher frequencies than at lower frequencies, and usually is. It's easy to absorb higher frequencies than low, so it's not uncommon to have problems at bass frequencies even when the room is pretty tame at midrange frequencies upwards.

Large rooms are easier to deal with than small rooms, by the way.

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Re: Easy way to stop an echo in a large room? [message #88576 is a reply to message #88544]

Sun, 05 August 2018 09:48

Jazzy
Messages: 78
Registered: June 2018

Viscount

Wayne Parham wrote on Sat, 28 July 2018 08:42

Large rooms are easier to deal with than small rooms, by the way.

If I understand correctly, large rooms will make the frequencies travel longer hence their energy won't be that much already they reach the walls.

What about concerts in open areas, is the echo setting from the equalizer needed?

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Re: Easy way to stop an echo in a large room? [message #88578 is a reply to message #88576]

Sun, 05 August 2018 10:49

Wayne Parham
Messages: 18792
Registered: January 2001

Illuminati (33rd Degree)

There is no echo in an open area outdoors. That is, of course, unless you're near a large rock cliff or something like that.

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Re: Easy way to stop an echo in a large room? [message #88830 is a reply to message #88544]

Sun, 16 September 2018 12:19

drake
Messages: 215
Registered: June 2016

Master

Wayne Parham wrote on Sat, 28 July 2018 13:42

Large rooms are easier to deal with than small rooms, by the way.

I had no idea that this was the case as the assumption has always been that the smaller the room, then the less the distance sound has to travel in order to produce an echo. I will probably have to research more on this.

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