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Discussion Starter · #1 ·
I hate to ask this, but I did a search to no avail....

What is the proper method of wiring in parallel for more than 1 pair of speakers? I've seen the line diagrams, but I am still unclear on where the connections or splices are actually made. This is for wiring 2 pair of ceiling speakers from 1 volume control.

Any insight is greatly appreciated!


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Just go from the volume control to the first pair. Then run from +/- of each of the first pair to the second pair on the same side. OR, you can home-run wires from each, twist the appropriate ends together, and attach directly to the control. Matters not - the result is the same.


Volume L+ -> L Spkr 1 + -> L Spker 2 +

Volume L- -> L Spkr 1 - -> L Spker 2 -


OR


Volume L+ -> L Spkr 1 + AND L Spker 2 +

Volume L- -> L Spkr 1 - AND L Spker 2 -



Repeat for right channel. Just make sure the amplifier can handle the reduced impedance. I assume you know that running speakers in parallel recuces the impedance by 1/2.
 

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What would you look for in the amp specs to ensure that it can handle the reduced impedance (see example below)? How would this affect the amp & overall system?


6 channel amp

2 channels --> room 1 w/ 2 speakers

2 channels --> room 2 w/ 2 speakers

2 channels --> room 3 w/ 4 speakers
 

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Discussion Starter · #4 ·
Thanks bpape...

My speakers are 4ohm-8ohm switchable.
 

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Quote:
Originally posted by anon-e-mouse
What would you look for in the amp specs to ensure that it can handle the reduced impedance (see example below)? How would this affect the amp & overall system?


6 channel amp

2 channels --> room 1 w/ 2 speakers

2 channels --> room 2 w/ 2 speakers

2 channels --> room 3 w/ 4 speakers
He would just switch the impedance switch on the volume control from 1x to 2x. This would double the load if the two sets are identical impedance/speakers.



Speakers in parallel are calculated by:

1/Load = 1/spkr A + 1/spkr B + 1/spkr C ...


where spkr A/B/C is the load of that speaker.


Ex. 1/Load = 1/8 + 1/8 = 2/8 = 1/4 = 4 ohms nominal for two sets of 8 ohm speakers.


Ex2. 1/Load = 1/8 + 1/6 = 3/24 + 4/24 = 7/24. Load = 24/7 = 3.4 ohms nominal for a set of 8 ohm and 6 ohm speakers.


Just look in the amplifier specifications and see if it is rated to drive the calculated load impedance.


B.
 

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I hope this question is ok on this thread..


Any advice as to speaker gauge/wire type (brand?) when running speaker runs, not exceeding 150 ft. from the home rack?


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Brian - Thanks for the info. Let me see if I really understand this.


6 channel amp (e.g., Marantz ZS5300)
Rated Power Output

Zone1 L/R (40Hz -20KHz) ... 60W 6-ohm / Channel

Zone2 L/R (40Hz -20KHz) ... 60W 6-ohm / Channel

Zone3 L/R (40Hz -20KHz) ... 60W 6-ohm / Channel

THD (40Hz - 20KHz) ... 0.05% 6-ohm

Input sensitivity ... 300mV / 60W Output

Input impedance ... 20K ohms

Frequency response (-1dB) ... 10Hz to 30KHz

Signal to noise ratio ... 85dB

Power requirement ... 115V / 230V AC 50/60Hz

Power consumption ... 100W

--

2 channels --> room 1 w/ 2 speakers (8-ohm each --> so at least 45W/speaker)

2 channels --> room 2 w/ 2 speakers (8-ohm each --> so at least 45W/speaker)

2 channels --> room 3 w/ 4 speakers (8-ohm each) but 4-ohm nominal --> so at best 22.5W/speaker)


My two concerns are...

1) there is no mention that this amp can handle 4-ohm impedance speakers so will this put undue stress on the amp?

2) even if the amp could handle this setup, won't the 4 speaker room have a much more quiet output?
 

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Actually, it doesn't quite work that way. As impedance falls, amp output usually rises. A REAL GOOD amp will be double. Most are a bit less, maybe 70% or so. So, assuming 35% gain from 6 ohms to 4, it would actually put out about 80W into 4 ohms.


If the amp is not rated to drive 4 ohms, then yes, it can stress the amp. The vast majority of amps can handle it but most also say so in their specs.


You can wire them in series in 4 ohm configuration and yield an 8 ohm load. Set the speakers in the other rooms to 8 ohms and then every channel 'sees' the same load. Wiring in series can cause some phase issues from a performance standpoint but without knowing how you are using these, I can't say if I'd worry about it or not. For instance, if it is for outside on a patio and you have 2 pairs spread out, who cares.


The other option is to get a couple big 2 ohm resistors and put them in series with the parallelled drivers. This will get you back to 6 ohms if your speakers are set @ 8. Just make sure the resistor is rated to handle the 60W that the amp will produce. This is obviously less desirable as it costs additional money but it will work.
 

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Quote:
Originally posted by bpape
Actually, it doesn't quite work that way. As impedance falls, amp output usually rises. A REAL GOOD amp will be double. Most are a bit less, maybe 70% or so. So, assuming 35% gain from 6 ohms to 4, it would actually put out about 80W into 4 ohms.
Yes, 80W to 4 speakers is 20W/speaker (& I calculated at best 22.5W/speaker).

Quote:
Originally posted by bpape
You can wire them in series in 4 ohm configuration and yield an 8 ohm load. Set the speakers in the other rooms to 8 ohms and then every channel 'sees' the same load.
This confuses me. :confused: By running the speakers in series as opposed to parallel my impedance is not reduced?


Sorry, but this is all new to me. I appreciate everyone's help very much!!!
 

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Series is R+R+R etc.


Parallel is 1/R+1/R+1/R etc.
 

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Ok. Used google & found info on running speakers in parallel, series, & series/parallel ( http://www.bcae1.com/spkrmlti.htm ).


Running in series & you add speaker impedances (2 x 8-ohm speakers --> 16-ohm total impedance).

Running in parallel & you divided the impedance by the number of speakers (2 x 8-ohm speakers --> 4-ohm total impedance).

Running in series/parallel & the impedance is unchanged (2 x 8-ohm speakers --> 8-ohm total impedance).


In addition to my 2nd question above regarding output, which wiring setup is better (series, parallel, or series/parallel)?
 

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Quote:
Originally posted by anon-e-mouse
Brian - Thanks for the info. Let me see if I really understand this.


My two concerns are...

1) there is no mention that this amp can handle 4-ohm impedance speakers so will this put undue stress on the amp?

2) even if the amp could handle this setup, won't the 4 speaker room have a much more quiet output?
Call Marantz and ask them if it can drive a 4 ohm load. If so, hook the speakers in parallel and be done. If the amp can do this without trouble then you shouldn't have a reduction in quality of sound.


More speakers = More output!! Any difference lost power-wise will be made up acoustically. If I remember correctly, double the drivers = 6 db more output. Double the power only = 3 db more output. (Someone correct me if I'm wrong.) Also, keep in mind that you normally aren't going to get close to rated power output and you won't be hurting for power.


Series/parallel connection is uncommon in home audio. With two sets of speakers I don't think it is possible to do this and maintain stereo sound. The diagram on the website you linked is for running woofers in a car audio situation. You could do it if you had 4 speakers per channel (8 total).


Amp- ---- -S1+ ------ -S2+ ------ +Amp (one channel)

AND Amp- ----- -S3+ ----- -S4+ ------ +Amp (same channel)


This would be duplicated on the second channel. Reverse +/- to alter phase.


S1 + S2 (assume 8 ohms) = 16

S3 + S4 (") = 16

1/Load = 1/16 + 1/16 = 2/16 = 1/8.

Total Load to single channel= 8 ohms.


Parallel would be best. See if the amplifier can comfortably drive the load. Most separate amps can handle 4 ohms fine.


B.
 

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Brian - Thanks. You are correct, I'd need 4 speakers per channel to wire series/parallel. I confused myself.


Also my math above is incorrect. If there is 60W/channel & 6 ohms then

a) running two speakers in series for that channel gives 16 ohms or about 25-30W effective power & ~15W/speaker

b) running two speakers in parallel for that channel gives 4 ohms or about 80W effective power & ~40W/speaker


So assuming the amp can handle the load, running the speakers in parallel will keep the power/speaker in a good range. (I'll email Marantz & see what they say.)


Thanks for everyone who helped clarify things for me.
 
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