Outdoor loudspeakers. Mono or stereo?

[SimonTHK]

So this is just a minor quistion
Would it ever be preferable to have stereo instead of mono for outdoor use? (in my situation, will come back to that).
I mean, stereo is probably made for a setup where the user are placed between the loudspeakers (besides or in front of the user), so that the sound can have a depth and be "moved around" in any position between the two loudspeakers.
But in my situation (used for an outdoor event with background music) people are moving around the loudspeakers, placing themselfes sometimes to the right of both loudspeakers or left of them both.
So why not just play mono?
Lets imagine the user are placed 10 meters from left loudpseaker and 15 from the right one. This will still provide some depth in the music, but the depth would be wrong.... So what would be preferable?

 

[audioguru]

Compromise.
Blend the stereo channels a little so that the few people in the "sweet spot" between the speakers hear some stereo but people near one speaker hear both channels blended into mono without completely missing the other channel.

 

[dr peppers]

The above is practised at roadshows and the like.
It does depend a lot on the type of music too, pop music tends to use stereo effects, even then the stereo content tends to be more effects than pan (moving the sound around).
If I was to setup some background music I'd downmix to mono and wind the treble down a bit, depends on what you like and the people your entertaining.

 

[Sceadwian]

I'm with AudioGuru, mix the stereo channels a little and play those alternating between speakers in the 'grid' to one channel or the other to attempt to retain some stereo effect.

Even then you won't get it all, and if it's all mono you'll still have sweet and sour spots due to the relation of speaker distance and attenuation of air, totally unavoidable.

You could if you wanted tune specific areas for stereo in a wide sweet spot but this jumps out of electronics into the realm of room acoustics which is totally different.

Good solid stereo reproduction depends on one thing and one thing only and that's only one signal is in the left ear and only one signal is in the right ear, outside of this there are a hundred shades of grey.

 

[Dean Huster]

Why bother to mix? If a solo part is fully on the left channel, a mix will only bring it out onto the right channel slightly and you miss a lot of it. Folks are wandering around everywhere outside, and I go full mono every time. Besides, if it's a party for example, who's really listening to the music vs. having a serious conversation with someone or hitting on them? And if you think about it, you reduce the wiring cost of the installation significantly just in wiring.

 

[Nigel Goodwin]

Why bother to mix? If a solo part is fully on the left channel, a mix will only bring it out onto the right channel slightly and you miss a lot of it. Folks are wandering around everywhere outside, and I go full mono every time. Besides, if it's a party for example, who's really listening to the music vs. having a serious conversation with someone or hitting on them? And if you think about it, you reduce the wiring cost of the installation significantly just in wiring.

I agree, mono is all you need - why waste time and money messing about making it partially mono?, the crowd wouldn't even notice anyway.

 

[SimonTHK]

Thank you. I allready have installations for the mono connections, but I wanted now to increase the music quality. I was not sure if this should be done by stereo or just some big speakers, since I use quite small speakers and I think that limits the quality outdoor, it just isnt enough.

Thanks for all the replies. I will most likely stick with mono, but even though stereo often seems useless outdoors, it might still give a better effect and experience of the music.

But being the stereo speakers are placed very close to each others it might still be worth looking into. hmm

 

[alec_t]

Because speakers are somewhat directional, particularly for the higher frequencies, IMHO it would be better to concentrate on using several good quality mono speakers aimed in different directions to give as uniform and wide a sound field as possible. Forget stereo.

 

[Sceadwian]

I agree, mono is all you need - why waste time and money messing about making it partially mono?, the crowd wouldn't even notice anyway.

I dunno, while in general mono isn't a bad idea a well designed outdoor stereo setup can sound substantially better, it is however substantially more work and figuring and the environment itself doesn't always cooperate.

 

[dr peppers]

If your concerned about directionality then pluck for speakers that have 2 or 3 mids and a tweeter (esp good for speech), or an mtm arragement, more of smaller drivers gives you less directional effect than one big driver, and if you spend a little more you can get cabinets with constant directivity tweeter horns, these sort of cabs will give you a good result esp in complex outdoor spaces or where theres people milling about.
If you want window rattling bass with this setup then you need bass bins, like I said the setup depends on the situation and music.

 

[audioguru]

If your concerned about directionality then pluck for speakers that have 2 or 3 mids and a tweeter (esp good for speech), or an mtm arragement, more of smaller drivers gives you less directional effect than one big driver

No.
Multiple mids or tweeters gives a very directional sound beam with some lobes.
Use one dome mid and one dome tweeter for a wide sound beam.

If you need the extremely high sound levels of a rock concert then use the huge horn tweeter horns (they sound like horns beeeep, beeeep) that are used at rock concerts.

 

[dr peppers]

When the sound wavelength becomes less than the diameter of the driver (1kc for a 12" driver), the driver becomes directional am I correct, as the driver goes into 'breakup' where diffrent parts of the cone radiate the sound wave both radially and coaxially, becoming more concentrated towards the voice coil as freq increases.
So if you have a number of smaller diameter drivers in a cab then your power rating goes up but your directionality remains reasonable, multiple small drivers seems the norm for speech cabs used in bingo halls and the like (I know these wouldnt necessarily be used for music).
I can appreciate side lobes being introduced from the location of the drivers and the differences due to tolerances and phase changes caused by time delays.
Eminence made a couple of compression driver horns that although not audiophile quality were very popular and produced very high spl's, in fact all my experience isnt audiohile grade, more cabaret or concert and outdoor music grade, hence my reply to the op.
Is there something I'm missing?, its been 15 years since I had anything to do with the sound business.

 

[audioguru]

When the sound wavelength becomes less than the diameter of the driver (1kc for a 12" driver), the driver becomes directional am I correct?, as the driver goes into 'breakup' where diffrent parts of the cone radiate the sound wave both radially and coaxially, becoming more concentrated towards the voice coil as freq increases.
So if you have a number of smaller diameter drivers in a cab then your power rating goes up but your directionality remains reasonable, multiple small drivers seems the norm for speech cabs used in bingo halls and the like.
I can appreciate side lobes being introduced from the location of the drivers and the differences due to tolerances and phase changes caused by time delays.
Is there something I'm missing, its been 15 years since I had anything to do with the sound business.

A number of drivers are physically spread out. Then the one that is farthest has its phase 180 degrees from the one that is close so the sounds cancel at high audio frequencies.
Are you talking about the muffled sounds from a telephone? A telephone does not produce high audio 'reewuen'ee' (translated as "frequencies" with the high audio frequencies missing).

An array of speakers produces a very directional sound beam exactly like an array of transmitting or receiving antennas that concentrate their sensitivity in one direction.

 

[dr peppers]

Right I think I know what you mean.
I was talking about a flat baffle with maybe 4 drivers screwed to it as close a possible, so that the whole thing acted as one driver, an L pad would be a proper way to connect them, but the ones I've come across are just series-parallel to get the 8 ohms.
My point was that this layout gives a better albeit maybe slightly than one huge driver as far as directionality is concerned.
In my experience large drivers esp 15" tend to not only 'searchlight', but frequencies that are in the searchlight freq range tend to be painfully shrill, I think this is caused by peaking (as in chebyshev filter), and or phase shifts.
I'm not sure what you mean about 'phone muffled sounds, something to do with passive crossovers maybe.

 

[audioguru]

I was talking about a flat baffle with maybe 4 drivers screwed to it as close a possible, so that the whole thing acted as one driver

No.
The slow speed of sound causes phase shift at fairly low and higher frequencies that causes cancellation of sounds.
Higher frequencies need a point source of sounds so they all have the same phase and no cancellations.

an L pad would be a proper way to connect them, but the ones I've come across are just series-parallel to get the 8 ohms.

No.
Modern amplifiers have a very high "damping factor" (an extremely low output impedance) that preventsa a speaker from resonating and sounding boomy or muddy.
L pads were used with very old vacuum tube amplifiers that had a poor damping factor because of their output transformer.

In my experience large drivers esp 15" tend to not only 'searchlight', but frequencies that are in the searchlight freq range tend to be painfully shrill, I think this is caused by peaking (as in chebyshev filter), and or phase shifts.

A large speaker is a woofer or sub-woofer for low and very low frequencies. It sounds awful at higher frequencies.
A midrange speaker is used for mids and a tweeter is used for highs.

I'm not sure what you mean about 'phone muffled sounds', something to do with passive crossovers maybe.

The terrible 300Hz to 3kHz bandwidth (frequently much narrower) of telephones was the best they could do a long time ago when the telephone was invented. They were happy with any sound even if it was muffled.
300Hz to 3kHz is "Vowels only". The important high frequency sillibants and consonants of speech were missing which makes the sound muffled and unintelligible. The low frequencies are missing which makes the sound tinny.
We hear to 20kHz when we are fairly young. Guns and other stupid loud sounds destroy our high frequency hearing.

I can't understand what you are saying because you sound muffled. What did you say?

 

[Dean Huster]

I dunno, while in general mono isn't a bad idea a well designed outdoor stereo setup can sound substantially better

That just doesn't make any sense to me at all. The premise of stereo is the listener sits where the output of two (or more) speaker channels recreate the original sound source, e.g., a symphony orchestra. The listener moving about the sound field is like an attendee of a sympony concert moving about the auditorium while the concert is in progress. Where are you going to place the left channel in your outdoor project? Are you going to strap the partygoers' feet to the concrete? Exactly how is the "balance" control on your amp going to function? No, I just don't see the sense and expense. This is getting into audiophoolery at that point.