So we've been doing several events recently with our system composed of 4 keystones, 4 hd15s and 2 syntripps. In most of the venues we have no issues at all but 2 of the events where in long narrow spaces and I found we where really struggling to get any bass to project any further than a few metres in front of the system. For context the systems where placed front centre 2-4m from the back wall facing straight forwards.
Now we normally don't struggle to have other places shaking but for these 2, we has no end of problems trying to eek anything out.
So the question is, how can I avoid this in the future? Would setting up more towards one side and toeing them onwards be an amount be enough to stop any standing waves or room modes? Are we placing the system too far from the back wall rather than closer and making use of the additional gain you would get from the rear wall/corner.
Does this sound like a standing waves/room modes issue? I know you can't eq it away or use delays as I tried pretty much everything I could think of bar trying to shunt the massive stack about to fix it!.
Tia
Now we normally don't struggle to have other places shaking but for these 2, we has no end of problems trying to eek anything out.
So the question is, how can I avoid this in the future? Would setting up more towards one side and toeing them onwards be an amount be enough to stop any standing waves or room modes? Are we placing the system too far from the back wall rather than closer and making use of the additional gain you would get from the rear wall/corner.
Does this sound like a standing waves/room modes issue? I know you can't eq it away or use delays as I tried pretty much everything I could think of bar trying to shunt the massive stack about to fix it!.
Tia
Yes, maybe experimenting with free modeling/measurement software would help.
https://www.roomeqwizard.com/
https://i-simpa.univ-gustave-eiffel.fr/
https://www.roomeqwizard.com/
https://i-simpa.univ-gustave-eiffel.fr/
The back wall one quarter wavelength reflection (speaker-boundary interference) at 2 meters would cause a null ~43 Hz, and a peak an octave above. Can't bring back the phase cancellation frequencies, and the peak makes the lack seem even more apparent.
http://arqen.com/acoustics-101/speaker-placement-boundary-interference/
There is a link to a calculator there, looks like this:
Sub placement up against the back wall corners will eliminate low frequency speaker-boundary interference, other than the ceiling boundary, though that cancellation would be localized.
The low frequencies are (mostly) omnidirectional, so toe in would have little effect, and won't change the room mode problems. The SynTripP with the secondary horn attachment have decent pattern control down to ~400Hz, so won't be affected much by speaker-boundary interference, point them where the people are.
Not much to do about the room modes unless spreading the four subs around the room, which would eff up any semblance of time cohesion, more poison than cure.
Sounds like you had the subs center clustered, in a narrow room the side wall speaker-boundary interference may be a problem too. And there is always that pesky ceiling reflection...
Putting a pair in each back corner would avoid that problem, and give a bass "power alley" (+6dB gain) down the center of the room. Always a compromise, but probably more even LF coverage than center cluster in a narrow room, and if your kicks and tops are co-located, better imaging and "punch".
Art