Thanks for posting that link. I read through it an thought aht the reaction to stereo there is lukewarm.

is a harmony central thread on the same topic. The conclusion seems to be
This topic comes up a few times a year. Do a search and you'll find more info. Pretty much boils down to 90% of people agreeing that stereo is a waste for the typical live sound at most venues

One method that is often mentioned is "dual mono". That means setting up two speakers on either side of the stage but feeding them exactly the same signal. This is mainly done for coverage reasons. Most horn-based speakers have a triangualar (as seen from the top) coverage area which doesn't map very well for a rectangular audience shape. So the basic idea is that the left speaker covers the left half of the audience and the right speaker the right half, but both speakers emit the exact same signal.
Since the Cylindrical Radiator(tm) loudspeaker has a very wide horizontal coverage area, it doesn't make much sense to run them in dual mono (why would you ?).

Hope that helps

so hilmar, are you saying that one pas sytem will cover as much as 2? I do find the coverage of the one exceptional. But i would think 2 would still be a more even coverage, or as i have stated before just having more speakers vibrating air of the sound source, even if not much difference in coverage, i would think even greater fidelity. am i wrong?.
Personally I do favor the "single" L1 approach. When you use two systems for the same signal on stage, each system will provide excellent coverage for the full audience area (in contrast to most conventional systems), so most listeners get two pretty much identical "copies" of the orginal signal, except that they arrive with at two slightly different times (unless you are right smack in the center). That will result in some "comb-filtering", so spectrally the single L1 version is clearly superior. Spatially, its more a matter of preference. In general, two systems will provide for a wider, less distinct image, although it will mostly collapse on the nearest system. For anything but a solo performance I think you are better of with a distinctly localizable image (i.e. sinlge L1). For a solo act, it's a tradeoff but I haven't done enough work on to have a clear preference for myself.

Hope that helps
yes, basically i am looking at this from a solo's point of performing, or to use for more on the lines of a conventional pa for more than 4 instruments or vocals. i think 2 systems will be all i'll be able to afford, but would .. do conventional systems also running dual mono have this same effect?If so, it has been negligable to me so far listening to other folks through conventional systems. my scenario would be basically to run left and right from a mixer to a left and right pas, and set bal in center on mixer for use as a basic pa. i on the other hand when i get another system, would have to experiment with running just the guitar through one, and the vocal through another. or as we discused puting one speaker about halway in the middle and use the calculated delay when feeding the one pas signal to the other. in your scenario above how is the system hooked up that causes the arrival of sound to the audience from one system to arrive at a different time. thanks for your time on this. Its just i'm trying to adjust i guess to this whole new approach. i think its slowy somewhat sinkin in, but still the whole spread thing is confusing to me. perhaps when i get the other system to try and experiment all will become more clear as i hear things in different hookups and configurations.
also basically i think i understand the concept of the bose system. and how great it must sound with everyone using their own pas in a band.
but even if that were not the case, i still think if was just going to buy a pa, i would still choose 2 pas over any conventional system. it just sounds so much better.
but maybe im just lookin at things wrong...a conventional pa feeds x amount of watts to a speaker on each side in mono. correct? dual mono? all things fed to it from the mixer are generally panned down the center.
so am i missing anyhting other than that the pas is going to use 2 separate amps to do this, where as the conventional is using one amp to drive both speakers. ahh...maybe i just taught myself something there? so the slight difference in arrival time of the sound at the audience would be because of the signal reachin 2 different amps at a slightly different time?
could this, or should this be corrected with a delay if the speakers are more or less set up across from each other as in a normal conventional system? or is it going to be that noticeable to non discerning ears.
if one was forced to use the systems in a conventional way, what would be the best setup scenario
also from a prior post i had a question on if i was to do the delay setup with 2 systems (1 spekaer further into the audience) far away in front does the other speaker have to be before the delay becomes a factor. is there a rule of thumb when to start adding the delay at a specific distance? or if its any distance in front of the other pas one just uses the formula you gave me. thanks
sorry this all takes awhile to sink in, i just want to learn and get the most out of my system(s) in the many different scenarios one finds thierself in. it always reflects on me, and even if my fault it would somewhat reflect on bose too if people think things didnt sound good. so far with the one system, although with some modifications as far as placement fo fedback and volume in problem rooms. i have had nothing but good comments. just want to do my best and keep it that way... :-)
Here are couple of commnents on this:

Not everyone runs a "stereo" PA in dual mono, but most experience sound people do.

With most dual mono systems the "interference" between the two signals is somewhat less pronounced since the speakers provide uneven coverage. E.g if you are on the left side of the audience the level coming from the left speaker is usually significantly higher than that from the right speaker so the interference is limited.

The source of the delay is NOT in the amplification but simply due to the time it takes the sound to travel from each speaker to your audience position. Sound travels at about 1 millisecond per foot. Say the stage is 20 feet wide and you are 20 feet away from the stage and 5 feet off center towards the left. Using good old pythagoras we find that your distance to to right speaker is 25 feet and your distance to the left speakers is 20.6 feet. That means sound from the left speaker has to travel 4.4 feet less to get to you and reaches you 4.4 milliseconds earlier than sound from the right. You cannot compensate with a processing delay, since the number to dial in is different for every location in the audience. In this example, if both speakers would emit a tone at 114 Hz, the tones would be exactly out of phase at your position and would cancel out. For 228 Hz they would be exactly in phase and would add with +6dB of gain (instead of +3dB what you normally would get for two speakers that are far apart).

Whenever it make sense to use a second system for added coverage you should use the approbriate delay. If its less than 20 feet you certainly wouldn't need a second system but if its more you definitely would benefit from a delay.

Hope that helps

ok i believe you got through to me that time. thanks for the patience. so i understand correctly then, the differenc e is since the bose covers area more efficiently than conventional systems, these phsing issues are more critical, and will be much more obvious than when using dual mono from an conventional system. and much more pronounced at different points in the audience. so the same would apply to the whole stereo issue to some extent. all based on the way that the bose sound covers the area more efficiently and evenly than conventional systems. although stereo maybe not as noticeable as far as the phsing issues because of different sounds coming from different speakers. but the stereo issue would still be a matter of the on or off axis of the sweet spot being more of a factor.
so if i have understood this correctly, another system for me may cause me more problems than really solving any, unless i would use the second system more than 20 feet away in front of me for simply more fire power and coverage that way.
in a listening evvirnment for myself, say stereo program recorded material, wher i can place myself in the sweet spot, certainly would be heaven.
but even a dj doin a live thing would be fine with one system running both left and right to the pas, unless they had the same firepower issue and needed more coverage for a larger room or dance floor.
i doubt anyone dancing is thinkin about whether the guitar is comin from the right or left speaker etc.
maybe the only way to go would be a line out to a regular pa, but i think if it was really needed the delayed bose in front with the delay would be a better way to go. but where would i place that bose system? one probably couldnr place it in the middle of a room. thanks again hilmar, you have been very helpful.
wfs.. it appears to me you are going for overkill here. To put one 20 ft in front of you seems a bit impractical and would probably mess up the audience's perception of the sound. The people stuck next the extra "out front" system will not get a good sence of direction where the instrument is, which is supposed to be point of this system in the first place. Just a thought.
well, basically 20 ft was just number, bad choice i guess. i dont think i would do that at that distance. i think i will just keep experimenting with the one pas i have till i learn more how it operates in different envirnments. as it seems 2 systems for a solo is overkill and probably would make things more compicated and sound worse than just using the one. unles i decided to just run my vocal through one system, and the guitar through the other. in that scenario i guess both would have extremely good definition. not sure unless it was a concert situation that the expense would be worth the extra lugging. though 2 systems then would give me vocals for 1 and either keyboard mono or guitar mono from the other. or even the keyboard in stereo. but from all the posts here, seems stereo is just not the way to go live, and i tend to agree.
i guess my toughest adjustment to this system is the volume i like and the volume the audience likes. in smaller venues where i cant get 7ft in front of the speaker, often when the audience thinks it sounds great its a bit too loud for me. or when i get it to where i like the sound, it seems its not loud enough for them.also i have to learn in these less than ideal rooms ( which are abundant as musicians know) maybe the best way to place the pas infront of me and how far, to where the audience and i are both fairly happy. its with the speaker behind me i seem to be running into problems. i expect as i use the syten more i will learn more on how it reacts in all these different scenarios.
sounds like maybe i just need to learn how to use one system effectively before i even mess with 2.
one thing that may help. i read somewhee in a post that when one is out of the field that the bose covers, it becomes more of a point source sound. if that is the correct terminology.
in a decent area with the system pushed pretty hard, what is the apprx throw distance of the system before that point source effect. is it measured in feet? or like a maximunm footage the system covers efficiently. some rooms that hold maybe 300 folks are small and wide, while others are longer.
i will keep experimenting. thanks again. i think i will take this sytem wherever i play and always use it for my monitor or source reference. but may have to feed a line out to a house system sometimes if the volume the audience wants is louder than what i would want to hear on stage. but its all new to me and i love the sound, so i must learn how to make it work.

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