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100v pa system advice please? |
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Jamiepahire 
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Joined: 17 October 2019 Location: Powys Status: Offline Points: 5 |
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 Topic: 100v pa system advice please?Posted: 17 October 2019 at 5:37pm |
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Hi Iam Jamie, just joined the group and after a little advice on a 100v system iam thinking about trying. Any advice more than welcome from you pros! I'm a electrician by trade but thinking of going into outdoor event pa systems with a trailer commentary box.
So I hate using harn horns for these events, poor sound quality and even worse music reproduction. My plan is to use a 100v system with Bose 802 speakers, 2 per tripod stand. Each speaker having a 100v transformer on the back keeping the speakers at 8 ohmn. Maybe a set of 6 tripods so having 12 802s, evenly spaced around the main arena ring of these events. Was thinking of tapping the transformers at 50w each, so 4 speakers per 100v amplifier. What's peoples opinion on this setup? A bit OTT? Cheers Jamie.
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csg
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Joined: 17 September 2007 Location: bedford Status: Offline Points: 6086 |
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Posted: 17 October 2019 at 6:43pm |
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802's are probably far from ideal - they are woefully inefficient and have poor to zero pattern control. stacked two high on tripods with decent transformers will make them unstable and highly vulnerable to being blown over by the wind - this is a real issue in this type of work.
One conventional and successful solution to around arena style layouts is to use a series of small waterproof column speakers on poles around the perimeter, this will give reasonable sound quality and will also be reasonably free of delay artefacts which will severely limit intelligibility if present. efficiency will still be much lower than a horn based system of course. Another option these days with the advent of amplifiers with very high voltage capability is to build some suitable enclosures which can be simply run " low impedance style", particularly where you are not bothered by bass. I have a large pile of twin 8" ( one of which is co-ax) 16Ω boxes which are completely weatherproof and have done literally 100's of outdoor shows for me over the past 10 years. They are highly successful, provide higher quality than 99.9% of exterior PA systems and are dead simple to rig and use, they just require an amplifier with plenty of voltage available to be run on the end of a couple of hundred metres of cable at up to 8 per circuit. We still have stock of large format vitavox GP190 straight horns for where we have to project sound some way, and with a decent comp driver on the back and a little HF lift and HPF they give surprisingly good sound quality and throw for ever. they come up second hand from time to time and may be worth the investment - but i would certainly agree that any re-entrant ( bullhorn) style speaker will sound fairly rotten no matter what you do.
Edited by csg - 17 October 2019 at 6:45pm |
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“The fact is this is about identifying what we do best and finding more ways of doing less of it better”
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madboffin
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Joined: 03 July 2009 Location: Milton Keynes Status: Offline Points: 1539 |
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Posted: 17 October 2019 at 10:09pm |
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A major problem with trying to use Bose 802's in this application is that they are designed to be used with very large amounts of EQ, normally provided by the Bose controller. The bass boost will saturate your transformers - they would need to be rated at hundreds of watts to handle the power.
I think you will need to find another solution. |
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APW
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Joined: 13 November 2012 Location: Kent, UK Status: Offline Points: 1174 |
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Posted: 18 October 2019 at 10:19am |
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As already stated 802’s are very inefficient, 4 cheap (£10.00 each) Faital-Pro 3FE25 3” drivers in a column enclosure driven with 80watts will give the same spl as an 802 driven with 240watts, and I bet the 3FE25’s will sound better!! |
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100 Volt-line
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Joined: 05 May 2011 Status: Offline Points: 122 |
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Posted: 18 October 2019 at 11:08am |
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We often use stand mounted Bose 802s for arena jobs up to 100m square. Run from QSC amps at 2 ohm, with pretty good results. Decent powerful amps and decent size (2.5 min) cable all the way. Digital desk run with the Bose Panaray controller set to full range, but with HPF set on the desk to 150 hz. Run with compression on desk too. Many compliments have been received with this system. Must be run from a DECENT generator. But beware, some events wont allow petrol gennies these days.
Anything bigger, and its 100v all the way. Columns are ok, as are EV Evid 6.2t's no more than 25 yards apart on 10ft scaff poles, 1 per pole, but these wont cut it at noisy shows. A good compromise are music horns such as Bosch LH1-UC30E or Toa CS-304 which bring reasonable results. It depends on what sort of events you are planning to cover. Steam rallies and tractor shows its standard horns (Toa TC-631M or Atlas Sound CJ46 with Toa drivers.) all the way for us, to cut through the background noise. Run and used correctly, these don't sound too bad. Two per pole, 50 yards apart, and angled down a bit. As someone else mentioned, straight horns such as the old Vitavox/Grampian/or GEC are brilliant for covering large areas for announcements only. No good for music due to low end cut-off, and beamwidth narrowing as frequency rises. And they need to be plenty high up, as are ear-shattering at close quarters. Use Toa drivers (TU-631M), but avoid the Atlas sound PD30T; twice as expensive and prone to leaking and diaphragm failure. There are plenty of 100v amps around with plenty of power these days, mains and mains/battery. This was a problem years ago as amps tended to be quite low powered, and hungry on the batteries. A 100w amp was considered big! There are some firms around who will still try to cover an arena with horns mounted on the roof of the commentary box. An old fashioned idea that only really works for showjumping rings etc. Anything bigger, dont bother! We have seven trailer units and doo well over 100 outdoor shows per year; but beware on the towing side, as any vehicle and trailer combination over 3.5 ton used for business is into tachograph territory, which is a whole new can of worms! Hope this helps, and good luck with your venture.
Edited by 100 Volt-line - 18 October 2019 at 11:41am |
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100 Volt-line
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Posted: 18 October 2019 at 11:12am |
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Oh, and buy an impedance meter and learn how to use it properly. Invaluable piece of kit!
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100 Volt-line
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Posted: 18 October 2019 at 11:34am |
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Anything else you want to know, just ask!
Edited by 100 Volt-line - 18 October 2019 at 11:35am |
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Jamiepahire
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Joined: 17 October 2019 Location: Powys Status: Offline Points: 5 |
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Posted: 18 October 2019 at 11:50am |
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Hi guys, really appreciate the help and advice so far. With running the 802s at 2ohm, 3 in parallel, how far could be at this low impedance? Would a 50m run be too long? Guess something like 6mm cable might be best at them runs.
Definitely will look into colum speakers on a 10ft scaffold pole on 100v system too. Any risk of banging poles in the ground with underground services etc? Most local events around here are done with a commentary trailer and a couple of large horns on the roof, that's it, to cover a large show site. Your deafened standing close, and cant make out anything close or far away. Looking to offer a service that far exceeds this level of service. Can anyone advise on what sort of price I would be able to charge to set up this for a 1 day event? I know it's a how long is a piece of string question. Cheers again for all your time! Jamie.
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100 Volt-line
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Posted: 18 October 2019 at 12:15pm |
802's at 2 ohm is 4 in parallel. It can be 75-100 m before we get to the first speaker in a run of 4 at the far side of an arena. 2.5 cable works fine, however we use QSC PLX3002 or sometimes a 3402 for the these, to allow for the power swallowed up in the cable; I2/R losses and all that. A 2402 usually does the nearer ones. But beware of Bose 802's popping drivers, especially if they are getting on a bit. Replacement genuine 802 drivers are expensive; however Blue Aran do some aftermarket drivers to the same spec that work really well. To be honest, any decent 12+horn 300w cab would be better than Bose; we just use them cos we have them. Poles bashed into the ground on a field are unlikely to hit any services, as there probably aren't any, but proper showgrounds are different, and its ALWAYS best to check. Put it this way, we have never hit any, but it has been known by marquee contractors etc! As for pricing, well I dont want to reveal anything on here, and it seems to differ all over the country. Make some enquiries locally, and see if you can find out what others are charging, and if its worth your while. There are some proper price bandits in this game who will do jobs for next to nothing. Even though you offer better quality and may want to charge accordingly , sometimes the customer just wants something that just works! |
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imageoven
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Joined: 28 March 2007 Location: Scotland Status: Offline Points: 2186 |
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Posted: 18 October 2019 at 1:48pm |
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DO you have 12 Bose 802's allready?
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Keep pushing on, things are gonna get better.
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Jamiepahire
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Posted: 18 October 2019 at 1:55pm |
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No dont have any 802 any more, used to have a set with the Bose controller and liked them. Seem to think they have waterproof properties too? Only benefit over standard cabs.
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Earplug
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Joined: 03 January 2012 Location: Europe Status: Offline Points: 7216 |
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Posted: 18 October 2019 at 3:18pm |
If you don´t have any already, really don´t bother with those. There are plenty of better options out there. Personally, I´d go for EV SX200/300. Good sounding cabs with excellent SPL, so no need for huge amps to drive them. "But beware of Bose 802's popping drivers" Yes - a big problem due to series loading. Lose one driver and the whole cab is lost.  |
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Earplugs Are For Wimps!
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Jamiepahire wrote: