c701e714   
   XPost: rec.audio.pro, alt.audio.pro.live-sound   
   From: dpierce@cartchunk.org   
      
   wardy wrote:   
   > Hi,   
   >   
   > Advice needed please from all you experts out there.   
   >   
   > I have a decent background in sound engineering and live mic/desk   
   > setups, however I am no expert.   
   > I want to find the best way of installing a particular system in a   
   > public venue.   
   >   
   > I am installing a Technics amp with normal Stereo output (+- L and +-   
   > R)   
   > I have to send the audio thru the amp to 12 separate speakers across a   
   > sprawling venue.   
   > I have purchased a mono splitter and a stereo splitter.   
      
   These are unnecessary.   
      
   > Firstly i tried the mono splitter so that each speaker would be mono.   
   > I tried to convert this stereo output from the amp to mono by   
   > combining the cables.  firstly i tried to wire both the + outputs from   
   > the amp into the + of 1 speaker cable and both the -  into the - of   
   > the cable. this however simply forced the amp to "click" off after a   
   > few seconds of sound so i presume it wasnt happy with the level of   
   > impedance of whatever.   
   > So a mono splitter is out.   
      
   The "mono splitter" is out because most modern solid state   
   amplifiers object VERY strongly to having their left and right   
   channel speaker outputs wired together.   
      
   You're damned lucky you didn't blow the amp up altogether.   
      
   > I am going to try the 6 way skytronic Stereo splitter next.   
   > I am going to run 2 cables from the amp to the splitter (for L & R)   
   > Then use the L and R channel from each of the 6 "rooms" on the   
   > splitter as a separate L or R speaker on either side of the room thus   
   > giving 12 speakers (6 L and 6 R).   
      
   You're WAY over-thinking this. Take all your splitters back   
   and get your money back. And then get a simply RCA "Y" cable:   
   one female to 2 males.   
      
   > I havent set up a system where this many (12) speakers need to be run   
   > by 1 amp before so need your input please so i can learn as much as i   
   > can about running multiple speakers from 1 amp.   
   >   
   > Q - Does this sound like the best (and cheapest) solution?   
      
   It's not: you've made it WAY to complicated.   
      
   > Q - Why did the amp click off when i was trying to join the stereo +   
   > and - outputs to make one mono + cable and one mono - cable?   
      
   Because what ended up happening is that the right   
   channel was trying to drive the left channel while   
   the left channel was trying to drive the right channel,   
   and the amp, in a desparate act of self-preservation,   
   threw in its protection circuit, saying, in effect,   
   don't EVER do that again.   
      
   > Q - anything you can teach me about wiring up Multiple speakers from 1   
   > amp using a speaker splitter from your own experience would be great.   
      
   No, becasue you don't need it.   
      
   It's real simple. To be complete, assume the speakers are the   
   same and they are all a nominal 8 ohm impedance. If they're   
   not the same, then it starts to get more complicated but not   
   tremedously so. If they are a different impedance, then we   
   modify the instructions somewhat.   
      
   So, you want to hook 6 speakers to each channel.   
      
   If the amp is safe for driving 5 ohm loads (probably is), then   
   do the following:   
      
   On the left channel, take the positive (usually red terminal)   
   and hook it to the positive (usually red) terminal of speaker   
   #1 using a single wire. Then connect that same temrinal, using   
   a single wire, to the positive terminals of speakers #2 and #3.   
      
   Now, take a wire from the negative terminal of speaker 1 (usually   
   black) and connect it to the positive (red) terminal of speaker #4.   
   Connect the black of #2 to the red of #5. Connect the black of #3   
   to the red of #6.   
      
   Now, connect the black of #4 to the black of the left channel of   
   the amplifier. Cnnnect the black of #5 and the black of #6 to the   
   black of #4.   
      
   Now, repeat this arrangement for the right channel, using speakers   
   7, 8, 9 and 10, 11, 12 respectively.   
      
   Now, each collection of speakers will present each channel of the   
   amplifier with a 5.3 ohm load, which should be okay.   
      
   Next, take your "Y" connector. Plug one of the male ends into the   
   left auxiliary input jack, and the other into the corresponding   
   right input (assuming you're using the aux inputs for your signal).   
   Connect whatever your source is to the female input.   
      
   Check all connections, turn it one, adjust your levels and it   
   should all work fine.   
      
   There are other ways that are more versatile and convenient, such   
   as using 70 volt line transformers (you'd need two rated at the   
   per-channel output of the amp and 12 each rated at 1/6 that power),   
   but you trade cost for convenience.   
      
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