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From: The Post Quartermaster on 16 Jul 2010 15:09 I've never quite caught on to the Ohms thing. If I am running two speakers (I forget the terminology - series or parallel) in a system in which the speaker cable runs from the power amp to the first speaker, and then another cable runs from that speaker to the second speaker, what must I calculate in order to safely run yet another cable from the second speaker to a third speaker? -- Careful how you respond. I have people! JC
From: Krooburg Science on 16 Jul 2010 15:31 On Jul 16, 12:09 pm, "The Post Quartermaster" <quartermasterextraordina...(a)postfiftyone.org> wrote: > I've never quite caught on to the Ohms thing. If I am running two > speakers (I forget the terminology - series or parallel) in a system > in which the speaker cable runs from the power amp to the first > speaker, and then another cable runs from that speaker to the second > speaker, what must I calculate in order to safely run yet another > cable from the second speaker to a third speaker? > -- > Careful how you respond. I have people! > > JC Daisy chaining speakers is a *parallel* connection which is electrically the same connection is hooking all the speakers directly to the amp terminals. The disadvantage to daisy chaining is that cable resistance is higher and electrical damping is lower since all the speakers go through a single cable to the amp. Anyhow, every time you take two identical speakers (loads) and connect them in parallel to the amp by either method, you effectively cut the impedance of the load that the amp "sees" in half. So two 8Ù speakers nets a 4Ù nominal load - nominal meaning average. Speaker impedance varies with frequency which can be very important depending on the amp and how well it can handle dips in impedance below nominal. Now adding a 3rd speaker requires the use of a formula since you're dealing with an odd number. The formula is Rt = 1 / [ (1/R1) + (1/R2) + (1/R3). I suffices to say that the load with three 8Ù speakers is ~2.66Ù. If your amp channel is rated to handle 2 ohm loads (four 8Ù speakers in parallel or two 4 ohm speakers in parallel), then 2.66Ù should work fine. If it's rated for 4Ù minimum, don't do it. - K
From: The Post Quartermaster on 16 Jul 2010 16:19 "Krooburg Science" <krooburg(a)gmail.com> wrote in message news:b6655c0d-5d42-481a-9cc9-92a6ac196193(a)z34g2000pro.googlegroups.com... On Jul 16, 12:09 pm, "The Post Quartermaster" <quartermasterextraordina...(a)postfiftyone.org> wrote: > I've never quite caught on to the Ohms thing. If I am running two > speakers (I forget the terminology - series or parallel) in a system > in which the speaker cable runs from the power amp to the first > speaker, and then another cable runs from that speaker to the second > speaker, what must I calculate in order to safely run yet another > cable from the second speaker to a third speaker? > -- > Careful how you respond. I have people! > > JC Daisy chaining speakers is a *parallel* connection which is electrically the same connection is hooking all the speakers directly to the amp terminals. The disadvantage to daisy chaining is that cable resistance is higher and electrical damping is lower since all the speakers go through a single cable to the amp. Anyhow, every time you take two identical speakers (loads) and connect them in parallel to the amp by either method, you effectively cut the impedance of the load that the amp "sees" in half. So two 8� speakers nets a 4� nominal load - nominal meaning average. Speaker impedance varies with frequency which can be very important depending on the amp and how well it can handle dips in impedance below nominal. Now adding a 3rd speaker requires the use of a formula since you're dealing with an odd number. The formula is Rt = 1 / [ (1/R1) + (1/R2) + (1/R3). I suffices to say that the load with three 8� speakers is ~2.66�. If your amp channel is rated to handle 2 ohm loads (four 8� speakers in parallel or two 4 ohm speakers in parallel), then 2.66� should work fine. If it's rated for 4� minimum, don't do it. - K Thanks. Our local chamber of commerce wants to run an outdoor speaker off of their system, which is http://www.americanmusical.com/Item--i-BEH-PAPACK It's a small town chamber and they just needed something lowpriced that had the capability to project sound both inside and outside during small festival and fleamarket type events. This one can be run both series and parallel so I guess it could be run with two speakers on one side and then use the other side for outside speakers. If that is the case, as long as I ran four speakers of the same ohms, I'd be alright? And, thanks for your response. A whole town of 3000 appreciates ya. -- Careful how you respond. I have people! JC
From: George's Pro Sound Co. on 16 Jul 2010 16:30 "The Post Quartermaster" <quartermasterextraordinaire(a)postfiftyone.org> wrote in message news:Krydne_cAKN0I93RnZ2dnUVZ_tSdnZ2d(a)giganews.com... > > "Krooburg Science" <krooburg(a)gmail.com> wrote in message > news:b6655c0d-5d42-481a-9cc9-92a6ac196193(a)z34g2000pro.googlegroups.com... > On Jul 16, 12:09 pm, "The Post Quartermaster" > <quartermasterextraordina...(a)postfiftyone.org> wrote: >> I've never quite caught on to the Ohms thing. If I am running two >> speakers (I forget the terminology - series or parallel) in a system >> in which the speaker cable runs from the power amp to the first >> speaker, and then another cable runs from that speaker to the second >> speaker, what must I calculate in order to safely run yet another >> cable from the second speaker to a third speaker? >> -- >> Careful how you respond. I have people! >> >> JC > > Daisy chaining speakers is a *parallel* connection which is > electrically the same connection is hooking all the speakers directly > to the amp terminals. The disadvantage to daisy chaining is that cable > resistance is higher and electrical damping is lower since all the > speakers go through a single cable to the amp. Anyhow, every time you > take two identical speakers (loads) and connect them in parallel to > the amp by either method, you effectively cut the impedance of the > load that the amp "sees" in half. So two 8� speakers nets a 4� nominal > load - nominal meaning average. Speaker impedance varies with > frequency which can be very important depending on the amp and how > well it can handle dips in impedance below nominal. Now adding a 3rd > speaker requires the use of a formula since you're dealing with an odd > number. The formula is Rt = 1 / [ (1/R1) + (1/R2) + (1/R3). I suffices > to say that the load with three 8� speakers is ~2.66�. If your amp > channel is rated to handle 2 ohm loads (four 8� speakers in parallel > or two 4 ohm speakers in parallel), then 2.66� should work fine. If > it's rated for 4� minimum, don't do it. > > - K > > Thanks. Our local chamber of commerce wants to run an outdoor speaker off > of their system, which is > http://www.americanmusical.com/Item--i-BEH-PAPACK > > It's a small town chamber and they just needed something lowpriced that > had the capability to project sound both inside and outside during small > festival and fleamarket type events. This one can be run both series and > parallel so I guess it could be run with two speakers on one side and then > use the other side for outside speakers. If that is the case, as long as I > ran four speakers of the same ohms, I'd be alright? And, thanks for your > response. A whole town of 3000 appreciates ya. > -- > Careful how you respond. I have people! > > JC JC that 518 mixer is not suitable for your stated use George
From: George's Pro Sound Co. on 16 Jul 2010 16:44
> > JC that 518 mixer is not suitable for your stated use > > George > see manual here http://www.behringer.com/EN/downloads/pdf/PMP518M_P0672_M_EN.pdf look to page 7 section 2.4 you can use 2 x8 ohm speakers TOTAL, this is sound system at its most basic do not try to hook 4 speakers up to this mixer or the magic smoke will leave this unit and leavee it for dead |