Audio in a hall
Discussion
In the hall, was the DJ using his own sound system, which could be placed optimally? or was he a using the halls own speakers which might be set in fixed positions?
Which part of the frequency bandwidth was the sound bad...........it may be useful to do some reading regarding the room's schroeder frequency. In simple terms the room behave differently at low and mid/high frequencies; the Schroeder frequency is the point where that change happens and is determined by the room's size / dimensions.
It is fairly easy to measure how reverberant a room is..........apps like this https://play.google.com/store/apps/details?id=com.... allow you to measure the room's RT60 reverberation time. The app should allow you to optimise the speakers position and also their angle relative to walls, with a view to improving / reducing reflections. This will only help to a certain degree...........if the room is highly reflective then some treatment will be needed.
The following link has some good information regarding how to make / specify absorbers and diffusers to improve the sound in 'difficult' rooms.
http://mh-audio.nl/Acoustics.html#top
Which part of the frequency bandwidth was the sound bad...........it may be useful to do some reading regarding the room's schroeder frequency. In simple terms the room behave differently at low and mid/high frequencies; the Schroeder frequency is the point where that change happens and is determined by the room's size / dimensions.
It is fairly easy to measure how reverberant a room is..........apps like this https://play.google.com/store/apps/details?id=com.... allow you to measure the room's RT60 reverberation time. The app should allow you to optimise the speakers position and also their angle relative to walls, with a view to improving / reducing reflections. This will only help to a certain degree...........if the room is highly reflective then some treatment will be needed.
The following link has some good information regarding how to make / specify absorbers and diffusers to improve the sound in 'difficult' rooms.
http://mh-audio.nl/Acoustics.html#top
Thank you.
The kit was from one company and the DJ only plugged his decks in. The hall was Olympia London main hall so fitting anything on a one off is just to much cost and big a project.
Just over 1/2 way from the DJ you could hear the same song out of phase, so way more then normally get.
My thinking is if you had more (all around) but smaller speakers you would not get such a dramatic effect.
The kit was from one company and the DJ only plugged his decks in. The hall was Olympia London main hall so fitting anything on a one off is just to much cost and big a project.
Just over 1/2 way from the DJ you could hear the same song out of phase, so way more then normally get.
My thinking is if you had more (all around) but smaller speakers you would not get such a dramatic effect.
Correct speaker placement is vital to ensure even coverage of sound and to minimise reflections.
The best way to evaluate placement is to play some music (but not too loud) and then walk around the open space (this needs to be done when the venue is largely empty). You will almost certainly find a "hole" where the volume is dramatically reduced. The way to solve this is to rotate the speakers a little at a time, until the sound level is relatively even all across the venue.
It's also important that the speakers are mounted above head level (plus a couple of feet) as it's quite amazing how bodies can absorb sound.
Doing all of the above will enable lower sound levels to be used, which should also help to minimise echo.
Of course, if the venue is only ever partially occupied - a lot of the above won't help to reduce the echo - for that you then need some kind of strategically placed wall treatment (e.g. heavy curtains).
The best way to evaluate placement is to play some music (but not too loud) and then walk around the open space (this needs to be done when the venue is largely empty). You will almost certainly find a "hole" where the volume is dramatically reduced. The way to solve this is to rotate the speakers a little at a time, until the sound level is relatively even all across the venue.
It's also important that the speakers are mounted above head level (plus a couple of feet) as it's quite amazing how bodies can absorb sound.
Doing all of the above will enable lower sound levels to be used, which should also help to minimise echo.
Of course, if the venue is only ever partially occupied - a lot of the above won't help to reduce the echo - for that you then need some kind of strategically placed wall treatment (e.g. heavy curtains).
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