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From: Krooburg Science on 16 Jul 2010 16:47 On Jul 16, 1:19 pm, "The Post Quartermaster" <quartermasterextraordina...(a)postfiftyone.org> wrote: > "Krooburg Science" <kroob...(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 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 > > Thanks. Our local chamber of commerce wants to run an outdoor speaker > off of their system, which ishttp://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 What do you mean by series/parallel? There is no such capability. And their is on "other side" on that amp. > 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. NO, not unless the speakers are all *16 ohms*. That amp is only a SINGLE channel rated at 4 ohms minimum impedance which means you can run only TWO 8 ohm speakers off of it, period. Also, it is an extremely weak amp by today's standards and underpowered for the speakers being pair with it in that package. The most that setup is good for is basic paging/announcements for a small crowd. Don't expect anything beyond that. No music beyond light background, no musical reinforcement. > A whole town of 3000 appreciates ya. > > JC They'd probably appreciate me more if they followed my recommendation & bought something of higher quality and output. That setup is bottom of the barrel. - K
From: The Post Quartermaster on 16 Jul 2010 20:16 "George's Pro Sound Co." <bmoas(a)yahoo.com> wrote in message news:g72dnT880qnRXN3RnZ2dnUVZ_tmdnZ2d(a)posted.fingerlakestechnologygroup... > > "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 > I believe that myself. But you see, it's going to have to be suitable because the wigs at the chamber say so. So, I'm going to hook up and let them see for themselves. I just don't want to be the reason by not doing the ohms thing correctly. -- Careful how you respond. I have people! JC
From: Krooburg Science on 16 Jul 2010 20:27 On Jul 16, 5:16 pm, "The Post Quartermaster" <quartermasterextraordina...(a)postfiftyone.org> wrote: > "George's Pro Sound Co." <bm...(a)yahoo.com> wrote in messagenews:g72dnT880qnRXN3RnZ2dnUVZ_tmdnZ2d(a)posted.fingerlakestechnologygroup... > > > > > > > "The Post Quartermaster" > > <quartermasterextraordina...(a)postfiftyone.org> wrote in message > >news:Krydne_cAKN0I93RnZ2dnUVZ_tSdnZ2d(a)giganews.com... > > >> "Krooburg Science" <kroob...(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 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 > > >> 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 > > I believe that myself. But you see, it's going to have to be suitable > because the wigs at the chamber say so. So, I'm going to hook up and > let them see for themselves. I just don't want to be the reason by not > doing the ohms thing correctly. So you're saying you're going to hook up 4 speakers anyway?
From: The Post Quartermaster on 16 Jul 2010 20:28 "Krooburg Science" <krooburg(a)gmail.com> wrote in message news:be38cb47-52a8-4808-89d2-35a49ccd2319(a)p11g2000prf.googlegroups.com... On Jul 16, 1:19 pm, "The Post Quartermaster" <quartermasterextraordina...(a)postfiftyone.org> wrote: > "Krooburg Science" <kroob...(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 > ishttp://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 What do you mean by series/parallel? There is no such capability. And their is on "other side" on that amp. > 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. NO, not unless the speakers are all *16 ohms*. That amp is only a SINGLE channel rated at 4 ohms minimum impedance which means you can run only TWO 8 ohm speakers off of it, period. Also, it is an extremely weak amp by today's standards and underpowered for the speakers being pair with it in that package. The most that setup is good for is basic paging/announcements for a small crowd. Don't expect anything beyond that. No music beyond light background, no musical reinforcement. > A whole town of 3000 appreciates ya. > > JC They'd probably appreciate me more if they followed my recommendation & bought something of higher quality and output. That setup is bottom of the barrel. - K It is all they could afford, and even that was a struggle. It is to be used only for announcments and some background music. I use sp4's with a yamaha 16 and a QSC 1800 and the chamber's little setup sounds as good as mine inside their little building. Mainly I suppose because I have to have mine set so low to keep from rattling the metal rafters and roof. <G> The reason for all of this discussion is because in the owners manual for the speakers, they show, on page 5, a picture in which they are running 4 B215XL's. They didn't pay any attention to the fact that picture shows them running out of a Europower EP2000. So, anyhow, when they called and asked, I just wanted to make sure I was on solid ground when I answered their questions. I've told them before that this was not a good idea, but I just wasn't all that sure of myself. So, thanks to all for the education. -- Careful how you respond. I have people! JC
From: The Post Quartermaster on 17 Jul 2010 09:18
"Krooburg Science" <krooburg(a)gmail.com> wrote in message news:2809b895-fc02-4203-8a7e-1958471e9ac3(a)m35g2000prn.googlegroups.com... On Jul 16, 5:16 pm, "The Post Quartermaster" <quartermasterextraordina...(a)postfiftyone.org> wrote: > "George's Pro Sound Co." <bm...(a)yahoo.com> wrote in > messagenews:g72dnT880qnRXN3RnZ2dnUVZ_tmdnZ2d(a)posted.fingerlakestechnologygroup... > > > > > > > "The Post Quartermaster" > > <quartermasterextraordina...(a)postfiftyone.org> wrote in message > >news:Krydne_cAKN0I93RnZ2dnUVZ_tSdnZ2d(a)giganews.com... > > >> "Krooburg Science" <kroob...(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 > > I believe that myself. But you see, it's going to have to be > suitable > because the wigs at the chamber say so. So, I'm going to hook up and > let them see for themselves. I just don't want to be the reason by > not > doing the ohms thing correctly. So you're saying you're going to hook up 4 speakers anyway? Yeah. I might have to give them an old pa system I have in the garage and figure out a way to maybe run out of a slave mixer or something like that but these folks are adamant about their system having some, at least one, outside speaker. One fellow told me to just run a cable out of the other speaker output on their system to an old 150 QSC I have and run that to a couple of speakers. I will probably keep trying things until I blow theirs up. <G> -- Careful how you respond. I have people! JC |