Help for newbe - church PA 100v or Low Imp speakers? - Page 2

veedubya · 17th January 2013, 10:46 PM

Hi Sreten,
Thanks, i understand. sorry I meant 2 low 'normal' PA speakers, not 100v.

Speedskater · 18th January 2013, 12:14 AM

The RaneNote paper:
Constant-Voltage Audio Distribution Systems:
25, 70.7 & 100 Volts
http://www.rane.com/pdf/ranenotes/Co...on_Systems.pdf

The Rod Elliott paper:
70/100V Line Amps Commercial Sound - 70V & 100V 'constant voltage' line public address systems. Learn the pitfalls before you get caught.
High Voltage Audio

veedubya · 18th January 2013, 12:45 AM

Thanks Kevin.. It's coming together..

Speedskater · 18th January 2013, 01:35 AM

In the US vendor Parts Express catalog, pages 235 to 242 are some reasonably priced commercial sound products. (Yes they are US 70 Volt system products, but I think that similar 100 Volt products are available)

Parts Express: the #1 source for audio, video & speaker building components

veedubya · 18th January 2013, 09:03 AM

Thanks Kevin.

chrispenycate · 19th January 2013, 03:41 PM

100 volt line systems work fine for music; well, assuming the transformers are good. Which means, of course, expensive. Middle of last century, if you wanted long lines they were the way to go; power amps were expensive, low impedance wire was expensive and difficult to install, power amps would often go unstable with long runs. Well, the last one still holds, so for more than a hundred metres or so I would recommend active speakers, but decent power amps are now dirt cheap, and the loss of a few watts in cabling not the problem it once was. So individual volume control can be done cheaper and easier with separate amps, which also gives the option of zone equalisation.
There are still a few applications for which constant voltage systems are easier, particularly where existing cabling to a distant point is basically telephone twin (and even then I've wired balanced input local amps) but not very many.

GoatGuy · 19th January 2013, 07:52 PM

Bottom line on what veedubya is doing...

DON'T use 70V / 100V speakers. Its dumb. They're "public address" transformer-driven, and suck in almost every musical way. Doesn't save money. Technically will drive further distances with nominally inexpensive distribution wire. He's already said his worship-space isn't all that large.

I recommend using RECYCLED quality equipment. There is a LOT of it out there, and pretty attractively priced. Its a church! The mice never have much money.

The biggest lesson(s) I learned in doing our own (see comment #2, page 1) is that having multiple, used, ALESIS RA-100 amplifiers ... and multiple output knobs, allowed something we never planned to need, but was critical: adjustment of the individual speakers where-ever they might be situated in the sound space. Our system was effectively "mono, 8 out", and it is totally flexible.

The choice of the Yamaha 01V wasn't "because" it is digital, but because it is "really, really good" in the microphone preamp department. After all.. we're making music, not noise. Its sliders are top-shelf, and getting one for like $500/used ($4500 new!) beats virtually any new, inexpensive mixer, hands down. Especially (and we didn't know about it when we bought it), it has absolutely magnificent compression that can be applied to all the microphone channels as needed. Really tightens up the "live" sound - again without having to buy anything more than just the mixer.

The last thing we learned was ... there's nothing special about speaker cable and long runs. Our longest was 85 meters (about 275 feet), because we had to route cables through basement spaces, up walls, across outer walls, through conduits... And the amount of output power and clarity after all those feet, using "Home Depot" 10 gauge power extension wire ... was amazing.

Remember folks - the church mice are always poor. Not in spirit, but money. Quality used equipment, set up with good microphones (new, not used) and good speakers (used, not new), tough speaker stands, tough microphone stands ... makes for a laudable system.

We simply don't even need to be talking about 70/100 volt "PA" systems.

GoatGuy

veedubya · 20th January 2013, 09:27 PM

Thanks GoatGuy/Everyone!
I've decided that with all this info (and more-researching) I'm going for some 12" Speakers Low Impedance - not 100v, as I get the impression they are for speach/background music NOT live small band.. Think the 12" (would like 15" but too bulky looking for the layout of the church) will give us what we need + possibly a few nearfield monitors speakers where extra sound dispursment may be needed! Will certainly make sure anything brought allows for flexability/future (thanks GoatGuy) ..
I love it when a plan comes together!..

veedubya · 20th January 2013, 09:28 PM

Thanks for your input chrispenycate! :-D

oldrenders · 2nd February 2013, 06:38 PM

I agree with the post from sreten. 100v systems are intended for systems with long speaker cable runs. By transmitting the speaker signal at a high-ish voltage, this minimises the losses due to cable resistance (strictly speaking impedance) losses. Exessive 4, 8 or 16 Ohm speaker cable runs can dissapate some of your wattage in the cable (as heat) and reduce the power delivered at the speakers. BUT, for typical stage set-up this will be OK, provided you use flexible cable of a decent cross sectional area - the fattest that you can make off into your chosen plugs! Don't bother with 100 ohm speakers. Good luck with the project.

18th January 2013, 12:14 AM	#12
Speedskater diyAudio Member Join Date: Sep 2002 Location: Lakewood, Ohio	The RaneNote paper: Constant-Voltage Audio Distribution Systems: 25, 70.7 & 100 Volts http://www.rane.com/pdf/ranenotes/Co...on_Systems.pdf The Rod Elliott paper: 70/100V Line Amps Commercial Sound - 70V & 100V 'constant voltage' line public address systems. Learn the pitfalls before you get caught. High Voltage Audio __________________ Kevin

18th January 2013, 01:35 AM	#14
Speedskater diyAudio Member Join Date: Sep 2002 Location: Lakewood, Ohio	In the US vendor Parts Express catalog, pages 235 to 242 are some reasonably priced commercial sound products. (Yes they are US 70 Volt system products, but I think that similar 100 Volt products are available) Parts Express: the #1 source for audio, video & speaker building components __________________ Kevin

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17th January 2013, 10:46 PM	#11
veedubya diyAudio Member Join Date: Jan 2013 Location: Stoke	Hi Sreten, Thanks, i understand. sorry I meant 2 low 'normal' PA speakers, not 100v.

18th January 2013, 12:45 AM	#13
veedubya diyAudio Member Join Date: Jan 2013 Location: Stoke	Thanks Kevin.. It's coming together..

18th January 2013, 09:03 AM	#15
veedubya diyAudio Member Join Date: Jan 2013 Location: Stoke	Thanks Kevin.

19th January 2013, 03:41 PM	#16
chrispenycate diyAudio Member Join Date: Aug 2006 Location: Geneva, Switzerland	100 volt line systems work fine for music; well, assuming the transformers are good. Which means, of course, expensive. Middle of last century, if you wanted long lines they were the way to go; power amps were expensive, low impedance wire was expensive and difficult to install, power amps would often go unstable with long runs. Well, the last one still holds, so for more than a hundred metres or so I would recommend active speakers, but decent power amps are now dirt cheap, and the loss of a few watts in cabling not the problem it once was. So individual volume control can be done cheaper and easier with separate amps, which also gives the option of zone equalisation. There are still a few applications for which constant voltage systems are easier, particularly where existing cabling to a distant point is basically telephone twin (and even then I've wired balanced input local amps) but not very many.

19th January 2013, 07:52 PM	#17
GoatGuy diyAudio Member Join Date: Dec 2012 Location: SF Bay Area	Bottom line on what veedubya is doing... DON'T use 70V / 100V speakers. Its dumb. They're "public address" transformer-driven, and suck in almost every musical way. Doesn't save money. Technically will drive further distances with nominally inexpensive distribution wire. He's already said his worship-space isn't all that large. I recommend using RECYCLED quality equipment. There is a LOT of it out there, and pretty attractively priced. Its a church! The mice never have much money. The biggest lesson(s) I learned in doing our own (see comment #2, page 1) is that having multiple, used, ALESIS RA-100 amplifiers ... and multiple output knobs, allowed something we never planned to need, but was critical: adjustment of the individual speakers where-ever they might be situated in the sound space. Our system was effectively "mono, 8 out", and it is totally flexible. The choice of the Yamaha 01V wasn't "because" it is digital, but because it is "really, really good" in the microphone preamp department. After all.. we're making music, not noise. Its sliders are top-shelf, and getting one for like $500/used ($4500 new!) beats virtually any new, inexpensive mixer, hands down. Especially (and we didn't know about it when we bought it), it has absolutely magnificent compression that can be applied to all the microphone channels as needed. Really tightens up the "live" sound - again without having to buy anything more than just the mixer. The last thing we learned was ... there's nothing special about speaker cable and long runs. Our longest was 85 meters (about 275 feet), because we had to route cables through basement spaces, up walls, across outer walls, through conduits... And the amount of output power and clarity after all those feet, using "Home Depot" 10 gauge power extension wire ... was amazing. Remember folks - the church mice are always poor. Not in spirit, but money. Quality used equipment, set up with good microphones (new, not used) and good speakers (used, not new), tough speaker stands, tough microphone stands ... makes for a laudable system. We simply don't even need to be talking about 70/100 volt "PA" systems. GoatGuy

20th January 2013, 09:27 PM	#18
veedubya diyAudio Member Join Date: Jan 2013 Location: Stoke	Thanks GoatGuy/Everyone! I've decided that with all this info (and more-researching) I'm going for some 12" Speakers Low Impedance - not 100v, as I get the impression they are for speach/background music NOT live small band.. Think the 12" (would like 15" but too bulky looking for the layout of the church) will give us what we need + possibly a few nearfield monitors speakers where extra sound dispursment may be needed! Will certainly make sure anything brought allows for flexability/future (thanks GoatGuy) .. I love it when a plan comes together!..

20th January 2013, 09:28 PM	#19
veedubya diyAudio Member Join Date: Jan 2013 Location: Stoke	Thanks for your input chrispenycate! :-D

2nd February 2013, 06:38 PM	#20
oldrenders diyAudio Member Join Date: Feb 2013	I agree with the post from sreten. 100v systems are intended for systems with long speaker cable runs. By transmitting the speaker signal at a high-ish voltage, this minimises the losses due to cable resistance (strictly speaking impedance) losses. Exessive 4, 8 or 16 Ohm speaker cable runs can dissapate some of your wattage in the cable (as heat) and reduce the power delivered at the speakers. BUT, for typical stage set-up this will be OK, provided you use flexible cable of a decent cross sectional area - the fattest that you can make off into your chosen plugs! Don't bother with 100 ohm speakers. Good luck with the project.