those thin aluminum Dayton 20" diameter re-entrant horns might not take a lot of physical banging/dropping abuse but at $69 a pair + ~$99 a pair for drivers + another $50 for a pair of sturdy tripod stands should make some noise in the vocal region. One reviewer says he got a clear echo from 500 yards away - not too shabby. - Just a thought.
A single line array box of 5 inch drivers - Dayton PA130, or MCM- Newark's similar driver (~$7 each shipped) might be good enough. IIRC, its about as loud as a PA130
Look here - also, consider there are discount coupons to work with Newark sometimes
http://www.newark.com/mcm-audio-select/55-1595/audio-visual-audio-video-loudspeaker/dp/11C1076
A single line array box of 5 inch drivers - Dayton PA130, or MCM- Newark's similar driver (~$7 each shipped) might be good enough. IIRC, its about as loud as a PA130
Look here - also, consider there are discount coupons to work with Newark sometimes
http://www.newark.com/mcm-audio-select/55-1595/audio-visual-audio-video-loudspeaker/dp/11C1076
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The real problem with a speaker rated at "105 dB" is that is the most it can possibly put out. Right before smoke starts pouring out of the voice coil and the amplifier is putting out almost unintelligible square waves. Speech has a high peak to average ratio, and this must be taken into account. Real world output will be 10 to 15dB less, measured on an SPL meter when you're starting to get distortion. Then subtract 30dB for 100 feet. Is 70 to 75dB enough? Probably not. A line array of dinky speakers won't do any better because of the poor power handling. Hit it hard, they heat up, and the sensitivity drops. A line array of beefy 6 inch drivers will do better, but to make it big enough to behave as a line source it will get bulky and pricey. Single or double 10" 2-ways work very well for voice, and are usually about a cubic foot per driver. Very easy to put on poles. Line or point source, don't skimp on the amplifier. Think 500-ish real watts. Doesn't need 2 ohm capability or incredible thermal capacity because it's not a rave. Average output will be under 100 watts. You do however want headroom so it can sound clean when you push 80+ dB at 100 feet.
since 70dB is the SPL of normal conversation, yes.
If there is a lot of background noise, then why are you conducting an auction there.
A single lousy watt will be all that is required, if that, most of the time, that's 125mW per driver, really not loud enough? fine go to 10W, 1.25W per driver, 108dB at 1m, 78dB at 100'.
His problem is not lack of power it's intelligibility.
Sorry, but your maths is wrong. I went through that earlier. It's 98dB at 2.83v input, which is 4w into the 2ohm load those drivers would present when they're all wired in parallel. You're already on half a watt per driver, so you lose 6dB on the numbers you've just presented.
Auctions can be noisy places - people shouting to be the highest bidder etc. I'd argue if it's one of those sorts of events, you want to be able to hit at least 90dB, cleanly, at the back seats.
To manage 90dB at 100', you need 120dB of clean output at 1m from the speaker. The little column just isn't going to do that, while a good 10" two-way will still have 6dB of headroom.
Chris
Auctions can be noisy places - people shouting to be the highest bidder etc. I'd argue if it's one of those sorts of events, you want to be able to hit at least 90dB, cleanly, at the back seats.
To manage 90dB at 100', you need 120dB of clean output at 1m from the speaker. The little column just isn't going to do that, while a good 10" two-way will still have 6dB of headroom.
Chris
I’m not looking at just building my own system. I definitely want to elevate it at least 7 feet. Is there any case where a pa horn would be better than a speaker? I’m strongly considering going with a speaker. There’s just so many brands and set ups that’s it’s very overwhelming. I will probably have to research the amp, mic, and speakers separately. I basically want a system that’s not going to need to get upgraded but rather added to. I’m first thing is to narrow down brands.
Where would you guys located the speakers? I’ve heard all front, all back, half front half back, and 2 front, 2 back, 2 sides so that they don’t have to be blasting. I’m trying to see if there’s a way to eliminate mic feed back in the positioning so I know how many speakers and where to put them.
Sorry, you don't want to build your own system? Or some of it?
Maybe you have to work out why you have problems being understood, is it distortion by the speakers, poor dispersion, resonances, maybe you have bad Mic technique, maybe you mumble, or maybe you're vague and contradictory, we can only guess.
But you reduce distortion by increasing sensitivity of a speaker, the principle is that the less the cone moves the less rubbish it produces (non-linear distortion), you can do this by using a bigger driver, a greater surface area will produce more spl, not always true, but in general it is, but the bigger the driver the less dispersion you get (bad for people who are not directly in front of the speaker), so you can increase driver surface area by using multiples of the same small driver as discussed above and my preference because it comes with a number of other benefits that outweigh some of it's disadvantages, imo.
Horn speakers are also a way to increase sensitivity, they do this through a kind of lever action, and they can work very well, but they can have issues, its all about compromises, sound system and speaker design is a big game of compromises, like the placement, you can put an omnidirectional speaker in the middle of the audience, which is the smallest distance to every listener you can achieve, but that may well mean that the closest listener is just 3' away, and since sound drops off 6dB for every doubling of distance, that is a big range to the furthest listener, you can overcome this by placing the speakers far away, say 60' from the whole group, then the drop off of sound will be much more even, and this may work very well outdoors but indoors the increased spl that you need to achieve this may well produce lots of other problems. It's all about compromises.
do you think a little column or two, each with 8 of those cheap 5" MCM (at Newark) MCM 55-1595 speakers would carry far enough? - they should be able to take 12 watts each peak - maybe that would be fun for home use if nothing else
I've used just one in a paper mache enclosure and it sounded pretty good
xrk971's T-S
Re=7.36ohm
Fs=137Hz
Qts=0.84
Qms=3.07
Qes=1.158
Le=0.265mH
Mms=5.48g
Vas=1.75L
I've used just one in a paper mache enclosure and it sounded pretty good
xrk971's T-S
Re=7.36ohm
Fs=137Hz
Qts=0.84
Qms=3.07
Qes=1.158
Le=0.265mH
Mms=5.48g
Vas=1.75L
That's one of the problems with line arrays - once you get to a really appropriate size driver (5, 6, or 8 inch) you need a line of tweeters as well. Cheap 1 inch neo domes can't handle any power - and slot loaded or ribbon tweeters (which would work) can get expensive. A single tweeter would work, but it's not a line source and won't be balanced or have the slow fall-off with distance. If a column (of either mids or tweets) is too short, you may as well just use a point source speaker. Far easier to buy off the shelf, especially in the price range that's probably under consideration.
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