Hi all, a lot of marching bands use a product like the voice machine from sound projections Voice Machine | Sound Projections
I'm wondering if a better box could be DIY'd.
Primary applications include playback of a metronome sound for a marching band to rehearse to. Live sound voice reinforcement to give instruction on the football field. Both of these things need to be wireless, so the typical solution has been to build Shure wireless units into the box.
Max SPL around 127 dB would be good, but louder is fine as a more efficient system might have longer battery life. Horizontal pattern should be around 80 or 90 degrees allowing us to get by with just one box.
It's fine if it only goes down to 300 hz ish because the metronome sound doesn't have much bass, and the voice can sound thin if needed in favor of just being a reliable, intelligible workhorse that doesn't weight too much. But if a different design could play down to 200 or 100 that could be really cool!
Battery operation is a must as this unit would be placed on the away side of a football field behind the marching band where there is no electricity. Looking for around 6 hours on battery or more.
Budget for everything (including the Shure wireless units) would be $3000.
I was thinking about the B&C dcx464 / me464 combo, but that might be overkill and cost prohibitive. I was also thinking about a decent compression driver / horn / plus some small ish woofers in a synergy kind of box. I've got a good cabinet maker than can help out if needed / access to high quality cabinet making tools.
I'm wondering if a better box could be DIY'd.
Primary applications include playback of a metronome sound for a marching band to rehearse to. Live sound voice reinforcement to give instruction on the football field. Both of these things need to be wireless, so the typical solution has been to build Shure wireless units into the box.
Max SPL around 127 dB would be good, but louder is fine as a more efficient system might have longer battery life. Horizontal pattern should be around 80 or 90 degrees allowing us to get by with just one box.
It's fine if it only goes down to 300 hz ish because the metronome sound doesn't have much bass, and the voice can sound thin if needed in favor of just being a reliable, intelligible workhorse that doesn't weight too much. But if a different design could play down to 200 or 100 that could be really cool!
Battery operation is a must as this unit would be placed on the away side of a football field behind the marching band where there is no electricity. Looking for around 6 hours on battery or more.
Budget for everything (including the Shure wireless units) would be $3000.
I was thinking about the B&C dcx464 / me464 combo, but that might be overkill and cost prohibitive. I was also thinking about a decent compression driver / horn / plus some small ish woofers in a synergy kind of box. I've got a good cabinet maker than can help out if needed / access to high quality cabinet making tools.
there's no way you can make a wood box be lighter than a molded pvc case, now if you had a 3d printer you'd possibly be able to better the sound machine on performance but cost would be a factor for a prototype device.
i like the thought of a synergy style design with that ME 464 horn that would be the direction i would go.
i like the thought of a synergy style design with that ME 464 horn that would be the direction i would go.
Max SPL around 127 dB would be good, but louder is fine as a more efficient system might have longer battery life.
I would propose a 36V Pedelec accu and a TPA3251 Class-D-amp. Yields about 100W into 4 Ohms.
To reach your desired output level I think a midrange horn construction would be your best option.
And btw - high sound level - long battery life - low weight
hey, there is no free lunch
I would propose a 36V Pedelec accu and a TPA3251 Class-D-amp. Yields about 100W into 4 Ohms.
To reach your desired output level I think a midrange horn construction would be your best option.
And btw - high sound level - long battery life - low weight
hey, there is no free lunch
There are quite a few portable units on the market but none of them are anywhere near powerful enough for what you want. I dont know about wireless side but for the active speaker I would consider going down the route of using maybe a "racing" car battery (purposefully light weight) and a car audio amp. Something like "PC680 Odyssey Extreme Racing 25 12v 16Ah Battery"
Amp wise there are lots of reasonably powerful car audio class D monoblock amps on the market
Then seek out super efficient compression driver and a 8" driver (250 rms?) which will do 100hz no problem. You should be able to fit all that into a box that isnt too big, and consider making it out of 12mm poplar ply (poplar is about 30% lighter than birch) and add some bracing in the bass drivers enclosure. You'll still end up with something in the order of 20kgs though.
Amp wise there are lots of reasonably powerful car audio class D monoblock amps on the market
Then seek out super efficient compression driver and a 8" driver (250 rms?) which will do 100hz no problem. You should be able to fit all that into a box that isnt too big, and consider making it out of 12mm poplar ply (poplar is about 30% lighter than birch) and add some bracing in the bass drivers enclosure. You'll still end up with something in the order of 20kgs though.
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