I'm doing another open day at our local park and would like to place my speakers as far apart as possible. My only concern is will I get a serious sound delay and how far can I go before it gets too bad?

Good question, it depends on the exact position of the speakers. If you put a set of cabs, say 20' each side it shouldn't cause prob's, but if you extend other set's of cabs to the back of the area they will here the sound then the "echo" from the front set. What you need is a digital delay unit, so that the rear cabs are delayed enough to match the "echo" from the front cabs.

Confused: ask Gary

Try this little Question and Answer which I found for you.

The speed of sound is approximately 340 m/s, so sound would take 0.088 seconds to travel to spectator 30 metres away, or 0.44 seconds to travel to spectator 150 metres away. Thats almost half a second delay to travel 150 metres.

Beat mixing would be OUT unless you've got monitor speakers very local to you, or split-cue on your mixer.

Also, as far as clarity...things start getting very complicated.... for example, say you had both speakers facing each other, but 150 metres apart. A spectator standing exactly midway between the speakers would hear both speakers simultaneously (wind at ZERO), but he/she would hear it almost half a second later than it left each speaker.

Also consider this...A spectator standing in the middle of an imaginary huge clock-face. The speaker is at the 6 oclock position 150 meters away, and a brick wall is at the 12 oclock postition. The spectator would hear the sound from the speaker almost half a second after it left the speaker, but then would hear the echo (from the wall) one second LATER still (almost 1.5 seconds since the sound left the speaker now)

Using multiple, smaller, speakers would reduce some of those distance issues, but not eliminate them all together.

Also the shear logistics of running very long speaker cables can be fraught too. If running 100metres of speaker cable tree-to-tree for ecample, you'll certainly need to support the hanging run with a length of rope or guy wire.

Signal loss shouldnt be too bad, however impedence (ohms) might be an issue... Chris?

Ideally a proper set of pa horns would be better but I don't pocess anything like that. Last time we did the same sort of thing we set up in a small building in the center of the park and played to the whole field. The problem was it was ok for the car booters over the other side of the park but not good for people walking past the speakers!