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Venue eq issues.

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mini-mad View Drop Down
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Post Options Post Options   Thanks (0) Thanks(0)   Quote mini-mad Quote  Post ReplyReply Direct Link To This Post Posted: 08 August 2015 at 5:24pm
...ok then theres way more i need to learn about it....
If it sounds like a gorilla is trying to escape, turn it down.
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Post Options Post Options   Thanks (0) Thanks(0)   Quote Jasonstry Quote  Post ReplyReply Direct Link To This Post Posted: 08 August 2015 at 5:36pm
My worst case was just two walls.....

http://peavey.com/support/technotes/soundsystems/boundarycancellation.cfm


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Post Options Post Options   Thanks (0) Thanks(0)   Quote Pasi Quote  Post ReplyReply Direct Link To This Post Posted: 08 August 2015 at 6:41pm
Originally posted by Jasonstry Jasonstry wrote:

My worst case was just two walls.....

http://peavey.com/support/technotes/soundsystems/boundarycancellation.cfm




Nice article, as long as you ignore his mathematics at the end.
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Post Options Post Options   Thanks (0) Thanks(0)   Quote Jasonstry Quote  Post ReplyReply Direct Link To This Post Posted: 08 August 2015 at 9:14pm
It is a long time since I looked at that and, tbh, can't be aresed right now. General idea is right though.

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Post Options Post Options   Thanks (0) Thanks(0)   Quote Darkstar Quote  Post ReplyReply Direct Link To This Post Posted: 09 August 2015 at 6:55am
I knew about boundary cancellation but never got to struggle so much with it until a few months ago: I had to set up a friend's soundsystem as fixed in a venue which is an austrian fort built around 1800, when that happened the town's ground was significantly below the current level because it was basically built on sand and stones so it kept getting lower but, the ground was constantly raised through the years by putting more stable ground components anywhere it could be possible.
Raising the fort was obviously not an option so it is now 1 floor below the street level, that means the soundsystem was installed inside a room with about 1m thick walls which had as much ground behind them as the whole city has.
For the first party the system was actually put up by my friend and here you can see how he placed the speakers. I must warn you that they were mainly placed there for aesthetics and space management purposes though. 



Room is very small, it's around 7m long and you could not hear the bass from the front at all. On the back of the subs though you were literally getting your internals shaken and killed by bass, it would've been cool enough for the peeps standing back there if it didn't hurt their ears when the party was over.

My thought was that the walls being "infinite" due to being underground were making even deep bass bounce tightly and the waves coming back from the wall to the front would cancel whilst the ones on the back were adding up, this was also a problem from the side walls and the ceiling.
My solution was to push the subs as close to the back wall as possible, so that it would give them the most natural position, and measure the exact room length to add it as a long delay on the LMS (I thought that's basically like subtracting the box lenght).
It worked, and now its response is pretty flat for such a room with difficult acoustics interaction.
The perfect setup IMO would've been to put just one stack in the middle with the tops a bit angled and separated but since it is physically impossible here's what I managed to do at best:



As someone already said, placing subs near walls could help but keep in mind it could worsen the situation instead so best way would be to do the invert phase, find the point at which they cancel the most and invert phase again as it was mentioned before.

PS: corners make it all worse, your best bet would be for you to do a single central stack

Edited by Darkstar - 09 August 2015 at 7:02am
Bass =/= Enough
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