2 center-rear surrounds off a single speaker-level output on a Yammie receiver?

Discussion in 'Archived Threads 2001-2004' started by Charles J P, Feb 21, 2002.

  1. Charles J P

    Charles J P Cinematographer

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    Associated equipment:

    Yamaha RX-V1200 receiver

    Paradigm Monitor 7 mains

    Paradigm CC-350 center

    Paradigm Mini Monitor surrounds

    - All speakers are manufacturer spec’ed at 8 Ohms

    I want to run two Paradigm Mini Monitors off the single rear-center channel speaker-level output of my Yamaha RX-V1200 receiver. I know I have the option of wiring them in parallel for a 4 Ohm load or in series for a 16 Ohm load. I know issues come up when driving lower impedance loads with amps that aren’t designed for it, so I actually took a look at my receivers manual :gasp:

    It gives some guidelines for running 4 Ohm mains, but doesn’t refer specifically to running or not running 4 Ohm loads out of any other channels. It only has this table lists configurations of 8 or 6 Ohm loads on other channels.

    So, I have a few basic questions.

    1)For multi-channel amps, is the load based on a total load, or is it per channel (i.e. would it be easier, harder or the same for a receiver to drive a single rear-center channel with a combined total 4 Ohm load vs. driving two 4 Ohm mains)?

    2)Do higher impedance loads present any problems? I have never really seen 16 Ohm or 32 Ohm speakers, but I have seen higher (32 – 100+Ohm) specs for headphones. Is there any reason why driving a 16 Ohm load would present a problem for the amp (I know it will affect the channel level, but all my speaker levels are at 0, +or- 1 or 2 dBs in my current room so adjustment is available)?

    3)What will happen if the receiver cant handle a 4 Ohm load? Will over-driving the receiver even once ruin it, or is this something I can test before I run all the wires permanently? Also, how will I know that I could test this now and not notice any problems and then later on find out that I have been killing my receiver?

    4)Installing my rear center speakers in parallel will be much easier then in series because they will be on opposite sides of a doorway that runs floor to ceiling. What would you guys do???? Play it safe with a 16 Ohm load or make the installation easier with the 4 Ohm load.

    5)Is there any cheap device that will balance the total load back to 8 Ohms without affecting the sound quality?
     
  2. John Garcia

    John Garcia Executive Producer

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    Do not run them off the internal amp's power, you will could cause damage.

    Run a splitter from the rear center out, and either a two channel amp or two separate amps for them.
     
  3. Charles J P

    Charles J P Cinematographer

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  4. Jim Thompson

    Jim Thompson Agent

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    You can wire them in series if you wish,the down side

    is that you'll have to boost that level to match.You can

    still run two separate wires to the speakers as if you were

    runnin them normally or in parallel.Just do your series connections at the receiver's speaker terminals.
     
  5. Charles J P

    Charles J P Cinematographer

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    How can I do a series connection at the receiver end. Dont you have to make a series connection at the point where you have two pair of terminals?
     
  6. DonnyD

    DonnyD Screenwriter

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    I have 2 rear center speakers hooked to my RX-V1, running parallel/ 4 ohm load without any obvious problem yet. At first, I kept checking the heat that may have been generated but do not feel this is an issue. I left the switch on 8 ohm too.

    I made my connections at the speaker, just running a set of leads from one to the other......
     
  7. Charles J P

    Charles J P Cinematographer

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    Hmmmm... one "no" one "yes-in series" and one "yes-in parallel" from someone who has a similar, but beefier amp than myself. I appreciate the info guys. Does anyone have a answer to my more general question RE: if 16 Ohms would create a problem other than having to adjust the level up? Also, I have always heard that going from 8 to 16 Ohms will lower the output by 3dB but two drivers in close proximaty, producing a mono signal, will raise the total output by 3dB. Is this accurate?
     
  8. John Garcia

    John Garcia Executive Producer

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    OK, I can say that your amp is not a piece of crap, so it will handle it without smoking. I don't mean to say that running it this way WILL cause damage, but the possibility is there. What will happen, when you turn the one channel up, is leave yourself with a bit less reserve power when demanding passages come up. I've done this myself with my mains once, when I was doing an A-B comparison. I listened to one, the other and then, just for the heck of it, BOTH. Worked fine, sounded fine, amp did not overheat after over a day like that. 16 Ohms is also nominal, as resistance will vary with load. If this channel will be run small, you will probably have no issue. The way I recommended, though more expensive and complicated, is still what I feel is the "right" way to do it.
    There IS a way to bring the total resistance back closer to 8ohms total, but I don't remember how right now...maybe just ad a THIRD speaker in series with the other two parallel? [​IMG] If I am not mistaken, it can be done with capacitors or resistors, as a center channel's array has to be brought down to a nominal 8ohms also, and this is likely done via the crossover.
    Give it a shot, see what happens. Try it both ways, and see what works. Good luck.
     
  9. Jim Thompson

    Jim Thompson Agent

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    Charles,

    To answer your question about the series connections...

    Receiver's single amp speaker connection to a pair of

    speakers with two wires coming back.

    Rec.pos + ====================== + pos

    wire speaker A

    =================== - neg

    splice

    =================== + pos

    wire speaker B

    Rec.neg - ====================== - neg

    Hope this helps.

    As far as a parallel connection,you'd probably be ok,but

    I'm not gonna tell you to do it.You could do a parallel conection and add an 8 ohm resistor to the positive or negative side of each speaker and this will give you a nominal 8 ohm load.you can pick up resistor at your local Rat Shack.
     
  10. Charles J P

    Charles J P Cinematographer

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    Lemme see if I got this right Jim.

    So, I would still start out with 4 wires, 2 pos; 2 neg.

    I take one pos and one neg from each pair and just twist them together at the recever end and seal it off. This wire does not go into the receiver. Now I have two wires at the receiver end and the spliced "sealed" third wire but I still have 4 wires at the speaker ends. I take one wire and hook it up to the receivers positive and the other end to the receivers positive. I take the receivers negative and hook it up to the other speakers negative. Then I just take the second wire of each pair at the speaker end, and plug them into the speaker... bridging the negative of the first speaker with the positive of the second speaker, but back by the reciever. Is this right? I have never heard of this method before, but it seems total logical.
     
  11. Jim Thompson

    Jim Thompson Agent

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    Yeah ,I think you've got it,I don't know what way you

    may have been thinking of originally,but there is only one

    way to hook the speakers in series.Whether you do it at

    the receiver or at the speakers,the wiring is the same electrically and would appear the same in a schematical drawing.

    I mean you could take a single speaker cable from the receiver's pos and neg terminals out to where the two speakers are and then do what I said.Remember that electrically all you've done is transport,essentially,the receiver's speaker terminals to the new location,The wiring would still be the same.Except that you could say run the pos. to the pos of speaker A then take a single wire/conducter and go straight from speaker A's neg terminal to speaker B's positive,Then take the neg of speaker B and run it back to the amplifier/receiver.This is the same hook up as I described up above,but now you are doing the series wiring at the speakers.Electrically it is the same.
     
  12. Charles J P

    Charles J P Cinematographer

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    I think I could not visualize what you were talking about at first,becuase its like having the "jumper wire" be a huge long loop. I always thing of doing it wit a small single wire that is only as long as the distance between the speakers.
     

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