Home Entertainment & Technology Resource

  1. This site uses cookies. By continuing to use this site, you are agreeing to our use of cookies. Learn More.

multiple speakers will i blow amplifier

Discussion in 'Speakers' started by sparktikus, Apr 10, 2009.

  1. sparktikus

    sparktikus Member

    Joined:
    Apr 10, 2009
    Messages:
    4
    Trophy Points:
    1
    Ratings:
    +0
    Last edited by a moderator: Apr 10, 2009
  2. Member 639844

    Member 639844 Former Advertiser

    Joined:
    Sep 2, 2007
    Messages:
    14,808
    Trophy Points:
    136
    Ratings:
    +1,134
    Hi and welcome to the forums.

    If your using the switcher so only 1 pair at a time runs then you wont have any problems. The 4 ohm speakers arent going to be any good for you really though as your amp will struggle to drive them properly. Basically the lower the ohm figure the harder they are to drive.

    If your planning on running more than 1 pair of speakers at a time its whole different ball game though.

    Jees its 1 o'clock, I'm going bed :D
  3. BlueWizard

    BlueWizard Well-Known Member

    Joined:
    Jun 19, 2007
    Messages:
    15,472
    Trophy Points:
    166
    Ratings:
    +2,759
    Take the impedance of one speaker, and divide it by the number of speakers on that amp channel, and you will have the total load impedance, assuming all speakers are the same.

    As an example, FOUR 8 ohm speakers connected in parallel -

    Rt = 8/4 = 2 ohms

    Your amp is not very likely to handle 2 ohms and survive.

    Expand on what you have already said if you want more information.

    Why are you doing this?

    As already asked, are you planning to use more than one or two speaker sets at once?

    What amp?

    What speakers?

    and...again...why?

    Steve/bluewizard
    Last edited: Apr 10, 2009
  4. sparktikus

    sparktikus Member

    Joined:
    Apr 10, 2009
    Messages:
    4
    Trophy Points:
    1
    Ratings:
    +0
    I am planning on using all speakers on at the same time, and generally just using the radio shack selector box as a glorified connection box for all speakers
    I want 8 speakers all on at the same time, these are for use in a shop
    any ideas

    thanks
  5. Member 639844

    Member 639844 Former Advertiser

    Joined:
    Sep 2, 2007
    Messages:
    14,808
    Trophy Points:
    136
    Ratings:
    +1,134
    You'll need 2 amp capable of running at 4 ohms, you could then add 4 speakers to each amp as long as they are 8 ohm rated speakers. Of course you would need some method of controlling the amps so at least one would have to be integrated.

    What amps do you have if any, same question for the speakers. If you need to buy stuff what sort of budget are you looking at. With the speakers being i a shop I take it they arent ever going to be played above moderate volumes which helps. I take it sound quality doesnt really matter as long as its decent enough for a shop/ There really are a whole heap of options but if your answer those questions you'll get some good suggestions.

    IMO, that Teac just isnt going to do the job.
    Last edited by a moderator: Apr 10, 2009
  6. BlueWizard

    BlueWizard Well-Known Member

    Joined:
    Jun 19, 2007
    Messages:
    15,472
    Trophy Points:
    166
    Ratings:
    +2,759
    When MoonFly says '...4 speakers on each amp...', he means two speakers on each amp channel for a total of 4 attached to a stereo amp.

    It is possible to wire four speakers in such a way that the total per channel inpedance is equal to that of a single speaker.

    You wire the speakers in gangs. Meaning you wire two speakers in parallel, then take those two gangs of two, and wire them in series.

    Two 8 ohm speakers in parallel equals 4 ohms. Now take two gangs of 4 ohms, and wire them in series, and the total is 8 ohms.

    This can be done in two gangs of two in parallel, then connected in series. Or, it can be done in two gangs of two in series, then connected in parallel.

    [​IMG]

    This assumes all the speakers are 8 ohms. Also, this would allow you to use just one stereo amp.

    We still need a few more details to give a clear and complete answer to your question.

    Steve/bluewizard
    Last edited: Apr 10, 2009
  7. sparktikus

    sparktikus Member

    Joined:
    Apr 10, 2009
    Messages:
    4
    Trophy Points:
    1
    Ratings:
    +0
    yes because it is a shop it will be moderate background music not loud
    is it a no no to connect all speakers to radio shack selector box
    i dont want to rewire really as i have already ran all cables back to this selector box

    is there any kind of splitter to buy that will do the job

    thanks
  8. BlueWizard

    BlueWizard Well-Known Member

    Joined:
    Jun 19, 2007
    Messages:
    15,472
    Trophy Points:
    166
    Ratings:
    +2,759
    You can wire the speakers as I've shown them in my diagram, back at the amp.

    If all the wires converge at the amp, that actually makes if very easy to wire as my diagram indicates. You just need to know which wires go to which speakers.

    I will also warn you that you can't NOT want to do something simply because you view it as inconvenient. We are dealing with electrical and physical realities here that must be adhered to. You can't wire large gangs of speakers willy-nilly. It has to be done in a logical and systematic way.

    The Radio Shack switch box doesn't help UNLESS, it is wired for impedance matching. That is, it uses a combination of resistors and wiring as indicated in my diagram to keep the impedance fixed within an acceptable range for most standard amps.

    Steve/bluewizard
  9. sparktikus

    sparktikus Member

    Joined:
    Apr 10, 2009
    Messages:
    4
    Trophy Points:
    1
    Ratings:
    +0
    i only have 1 output channel of the amplifier unit
    is it possible to wire 8 speakers into this???
    thanks
    and how does impedance matching work
    thanks
  10. ben.bayliss

    ben.bayliss Member

    Joined:
    Feb 4, 2007
    Messages:
    1,129
    Trophy Points:
    63
    Ratings:
    +135
    TBH I'd be looking at using a cheap-n-nasty amp designed for PA use. None of them have trouble at 4ohms, and most would be happy within reasonable limits at 2ohms.

    You may think that being a shop we're talking low levels, but just think about how loud the insides of many shops are once you've got music+outside noise+talking+people moving around etc. etc... It's probably going to be running quite loud.

    Can't see how the switcher helps you at all tbh, apart from acting like a posh terminal block for cramming all the cables in to! :)
  11. RAmeeti

    RAmeeti New Member

    Joined:
    Nov 15, 2013
    Messages:
    2
    Trophy Points:
    1
    Ratings:
    +0
    I appreciate your diagram but more questions exists. While I understand that each diagram results in the same net electrical effect of having 8 ohms, is there any reason to select one over the other? The Parallel/Series vis Series/Parallel is confusing as unless those words are understood, it is not clear where the division is between the two diagrams. Does the divider go as a line up and down between each row or between each column. There is no clarity as two which speakers are right and which are left. Since the receiver will have 4 posts for a pair of speakers, it is confusing since only 2 posts are shown for 4 speakers. Lastly, what is the net effect or downside of wiring in series (so as to not reduce the resistance). Your wiring does keep second set of speakers from becoming a 4 ohm system but there must be some reason or downside.
  12. Philip4242

    Philip4242 Member

    Joined:
    Jan 15, 2008
    Messages:
    748
    Trophy Points:
    28
    Ratings:
    +94
    Well, my question is 'Why are you asking questions about a 4-year old+ Thread ?!?' :nono:

    Doing a Forum or Google search for 'series or parallel connection' should answer all your questions.
  13. spyder viewer

    spyder viewer Moderator

    Joined:
    Dec 18, 2007
    Messages:
    5,001
    Media:
    10
    Albums:
    3
    Trophy Points:
    136
    Ratings:
    +914
    This thread is answering a specific question and I'm not sure that you understand the problem the OP was seeking to solve. It would be better if you could start a new thread and specify exactly the problem you are seeking a solution to. If you are just trying to further your knowledge without seeking an answer to a specific question, carry on here and that being the case hopefully members will be sympathetic!
  14. RAmeeti

    RAmeeti New Member

    Joined:
    Nov 15, 2013
    Messages:
    2
    Trophy Points:
    1
    Ratings:
    +0
    I found the thread answering the same question that I had. But... it seems to leave some questions unanswered. Repeating those questions would be: 1) Both the Series/Parallel & the Parallel/Series show each of them going to 2 terminal posts yet 2 speakers will have 4 posts on the receiver, thus I am confused. 2) Each of those diagrams show 4 speakers but do not clearly indicate which will receive the right channel and which will receive the left channel. 3) If wiring in Series overcomes the Parallel problem of reducing the impedance, there must be a downside, else all wiring would be in series to never again have a problem wiring in Parallel an having too low an impedance and ruining an amp. 4) Is there a benefit from wiring in one of the two diagrams over the other. They are both shown yet the user is left to wonder why to pick one over the other. I do have the same need as the OP.
  15. spyder viewer

    spyder viewer Moderator

    Joined:
    Dec 18, 2007
    Messages:
    5,001
    Media:
    10
    Albums:
    3
    Trophy Points:
    136
    Ratings:
    +914
    Ok I'll answer as best I can. The OP wished to use more than one speaker on each channel. Now putting two speakers in series would increase (double) the impedance seen by the amplifier. The current would be reduced so the effective output would be reduced. To compensate for this, two such pairs of speakers could be wired in parallel (the right hand drawing). Thus twice as much current would be drawn and the impedance seen by the amp would be restored to 8 ohms. Alternatively, two speakers could be put in parallel. The current drawn from the amp would be doubled which might put it under strain. We therefore double up the speakers by putting two pairs of paralleled speakers in series restoring the impedance to 8 ohms as shown on the left. The current come down and the amp is safe. The drawings above are just two optional solutions to the one problem. If you wanted to apply this solution to a stereo situation, you would need 8 speakers. The option you pick is up to you.
    Last edited: Nov 16, 2013
  16. PSM1

    PSM1 Well-Known Member

    Joined:
    Dec 20, 2008
    Messages:
    18,967
    Trophy Points:
    171
    Ratings:
    +3,067
    Although the impedance the amp has on it is kept in a safe range that is a lot of speakers to drive with one amp. There is only so much power the amp can deliver and spreading that over so many drivers can not be great for sound quality etc.

Share This Page