Sam 45 Posted February 16, 2009 Report Share Posted February 16, 2009 If i was to wire an amp to 4 speakers in a cab say. How would i go about doing this? Would it be a series or parallel circuit ect?CheersSam Quote Link to comment Share on other sites More sharing options...
jamesbroonbreed Posted February 16, 2009 Report Share Posted February 16, 2009 Depends on impedances and all that pish.GOOGLE Quote Link to comment Share on other sites More sharing options...
soundian Posted February 17, 2009 Report Share Posted February 17, 2009 Series circuit: RT=R1+R2+R3+R4Parallel circuit 1/RT=1/R1+1/R2...RT=total impedance So for 8 ohm speakers:series: RT=8+8+8+8=32 ohms your amp probably won't like a 32 ohm load.parallel: 1/RT=1/8+1/8+1/8+1/81/RT=4/8RT=8/4=2 ohms A lot of amps don't like 2 ohms eitherSOLUTION: parallel-series Wire them in series as pairs, then wire the pairs parallel.for a pair, RT=8+8=16 ohmstwo 16 ohm pairs paralleled1/RT=1/16+1/16=1/8RT=8 ohms This way 8 ohm speakers present an 8 ohm load to the amplifier, 4 would give 4, etc. Quote Link to comment Share on other sites More sharing options...
sexytunk Posted February 17, 2009 Report Share Posted February 17, 2009 Bloody hell Ian, Anyone would think you're a sound engineer or something! Quote Link to comment Share on other sites More sharing options...
Al Coholic Posted February 17, 2009 Report Share Posted February 17, 2009 SOLUTION: parallel-series Wire them in series as pairs, then wire the pairs parallel.for a pair, RT=8+8=16 ohmstwo 16 ohm pairs paralleled1/RT=1/16+1/16=1/8RT=8 ohms This way 8 ohm speakers present an 8 ohm load to the amplifier, 4 would give 4, etc.There is actually a difference between SeriesParallel (pairs in parallel wired as series) and ParallelSeries (pairs in series wired as parallel). Eg, if one speaker fails in SeriesParallel you have 3 left, whereas if 1 fails in ParallelSeries you have 2 left. Not sure if that is the reason, but i read somewhere that SeriesParallel is more common. Quote Link to comment Share on other sites More sharing options...
soundian Posted February 17, 2009 Report Share Posted February 17, 2009 There is actually a difference between SeriesParallel (pairs in parallel wired as series) and ParallelSeries (pairs in series wired as parallel). Eg, if one speaker fails in SeriesParallel you have 3 left, whereas if 1 fails in ParallelSeries you have 2 left. Not sure if that is the reason, but i read somewhere that SeriesParallel is more common. I wouldn't think series-parallel is common. Firstly every 4x12 I've looked in has parallel-series wiring. Secondly, look at what happens when one speaker fails. P=IV V=IR P=V^2/R parallel-series: If one of a pair fails the other has it's circuit disconnected. RT increases to 16 ohms so P is halved (well, it isn't actually because the ratio depends on the apparent load in the amp in parallel with the apparent load from the speakers). Both speakers will take, nominally, the same amount of power as they were doing, reducing the risk of blowing another.series-parallel if one speaker fails you have 8 ohms from the single and 4 ohms from the parallel giving 12 ohms. So you're getting more power than the parallel-series circuit. Not a problem, you've got 50% more speakers to deal with it. Except that the single speaker will take 2/3rds of the power, meaning it takes almost double the power it was dealing with in a 4 speaker combination Plug in some numbers and you'll see, assume V^2=800:4 speaker working: any configuration Total power to cab=800/8=100 Wpower per speaker=25 WPS: One speaker deadTotal power to cab=800/16=50Wtotal power per speaker=25WSP: One speaker deadtotal power to cab=800/12=66.6 W8 ohm series speaker will take 2/3rds of power and 4 ohm parallel speakers only 1/3rdPower per speaker: series 44 W, parallel 11 W As you can see, one dead speaker could quickly become two dead speakers. Quote Link to comment Share on other sites More sharing options...
Pierre Von Mondragon Posted February 17, 2009 Report Share Posted February 17, 2009 "As you can see", comedy gold classic.To the untechnical that could be anything, leave it to those who know I say. Quote Link to comment Share on other sites More sharing options...
Al Coholic Posted February 17, 2009 Report Share Posted February 17, 2009 Ok.... Lucky SamL4 didn't ask about wiring an 8 speaker cab. Quote Link to comment Share on other sites More sharing options...
Recommended Posts
Join the conversation
You can post now and register later. If you have an account, sign in now to post with your account.