For you EE freaks :P

Discussion in 'Home Theater Projects' started by Allen Ross, Apr 23, 2003.

  1. Allen Ross

    Allen Ross Supporting Actor

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    Okay I am only a Freshmen EE at UMaine and I have been getting the hardware itch recently, (must be all the assembly code I am learning) and I want to start my first real EE project. Seeing that this will be my first I don't want do anything too much, so I have decided to build a Speaker selector.

    Okay I know it’s a really small project but I want something that is solid. When I say solid I mean something that will last my lifetime, and can handle any power that I through at it (500W). I don't see this as something that I will really need now but something that I will be able to use with any system I own in the future, or that my kids will have.

    I am thinking of using really nice binding posts, none of this push terminal crap. With the ability to select 3 speakers minimum. I am also contemplating using knife switches (gold plated if I can find them to reduce chance of corrosion). I want to put this in a nice brushed aluminum box, or something similar. With the knife switches on the top or the side.

    For a schematic, I will tie the ground to all the channels and I will just be switching the hot. Seems simple enough for me.

    So my question is, where the heck can I find some of these components? The binding posts are simple PE or MCM, but the knife switches? I have no clue, same with the box.

    Another thing is price, I am looking to spend no more the 100 bucks, I think this is very doable.

    So tell me what you think, should I consider different switches?
     
  2. Michael R Price

    Michael R Price Screenwriter

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    It sounds like a good idea, but I'm just curious... for what purpose do you need a speaker selector? I just sort of think that there are a lot of more interesting things you could build easily too... but, the selector which would definitely be something unique.
     
  3. Allen Ross

    Allen Ross Supporting Actor

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    so i can have multipil speakers going off of my reciver, when i go into speaker AB mode, it cuts out all my ablility to adjust levels, and it cuts out my ablity to use 5.1

    I know i will be driving my reciver at a 4 ohm load but i think it can take it [​IMG] (final last words)

    Plus i can't really think of anything else to so as a small project


    BTW, i haven't been able to find any knife swithces that can take any sort of real load, so i found these half way down theres some nice DTSP switches that can handle 20apms at 120VAC i think that should be heavy enough [​IMG]
     
  4. Allen Ross

    Allen Ross Supporting Actor

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  5. Dave Milne

    Dave Milne Supporting Actor

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  6. Paul Stiles

    Paul Stiles Agent

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    Another possibility is using switches to control some DC controlled (coils rated for DC voltage) relays that have heavy duty contacts. If you are really persistent/lucky, you may get some relays in hermeticly sealed cases that have nitrogen (or some other relatively non-reactive gas) inside.

    Paul
     
  7. Allen Ross

    Allen Ross Supporting Actor

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    yeah i don't know why that link worked
    heres the correct one.

    I thought about the switching under load and i came to the concustion that the best way to do it is just shut off the speakers when i am switching.

    I still have to work out the Resistance of the selector, i think if i just put some resistors in parrale, or have a toggle switch that can add a resistor in series to the curcuit then i think i will be all good.

    BTW i like the over kill on the switches, you never know what i will be running [​IMG] Nothing is excessive like excess
     
  8. Brian Knauss

    Brian Knauss Stunt Coordinator

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    The 6A switches are basically overkill. You receiver is never going to put 100W out per channel (unless you clip it like crazy)

    Don't get the WBT overpriced binding posts. Just get the good ol PE gold plated ones. Call it a day and then look at your fatter wallet.

    Still lost on this whole reason for the project. Are you trying to duplicate the sound from each channel to the rear speakers? You'll have a harder time correcting the imaging among various other problems. Doesn't your receier have a handful of settings that use the surround outputs?
     
  9. Allen Ross

    Allen Ross Supporting Actor

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    i am doing this to mirror image the settings that my reciver can do with surround sound and my A speakers. its really werid

    when both A and B are on, i can only adjust A's left and right, and no sub. I will mainly use this when i want to have the same sound in multiple rooms, IE have one set in one room and another in another, and still have the ablility to adjust, my levels. I might put the slector on my surrounds and have them switch between room speakers or i might have my mains, i still haven't made my mind.


    As for the switches, i am all about putting high current through this beast I will have to agree that 30A is a little much, but i want this thing to stand out and have some authority. Plus i don't know what kinda power i will be using this with. I might even use it for a sub switch, cutting power from one driver to another if i have multiple subs, one for muisc/one for HT, you never know. But i juat want this thing to not be the limiting factor in my system.

    I have also contemplated another isusse, isolation, if i am going to snag that nice aluminum case how am i going to issolate the singnal from the chasse, some rubber washers or will it just be fine with the supplied hardware?
     
  10. Charles M Berry

    Charles M Berry Stunt Coordinator

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  11. Allen Ross

    Allen Ross Supporting Actor

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    sad to say i think my dorm HT is better then yours, by one word alone TEMPEST, although i would love a HK receiver [​IMG] WE have gotten 110DB listening to just general music, and i have had point source on my tempest well above 115DB[​IMG]
     
  12. Javier_Huerta

    Javier_Huerta Supporting Actor

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    OK, here's an even *better* idea I've been fooling around with.

    Build a 6-output, 6-input speaker selector. Switch it to one out of 6 possible positions, and re-arrange the sonic orientation on your hall.

    Why would anyone do this? Simple. I have a 6.1 system on my living room, and it's perfectly symmetrical. Depending on where I'm sitting, though, I'd like the front channel to be exactly in front of me.

    Odd, I know, and I'm sure nobody else would have any use for it. But I *¨still* want to build it. [​IMG]
     

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