Results 1 to 10 of 10

Thread: gain setting bridged litebox4

  1. #1
    Member hottcakes's Avatar
    Join Date
    Sep 2010
    Location
    Dixon, IL
    Posts
    77

    gain setting bridged litebox4

    so i've one of them litebox4's that were all the rage a while ago and have been pondering about using it bridged. only issue i've run into is how would i go about setting the gains on the thing correctly since it has one pot per channel. elsewhere that i posted the question only had two suggestions: either i use a dmm to get the numbers i'm looking for, or trying it by playing some music at a low volume and trying one gain at a time to see if only one affects the actual output.

    i'm not a fan of the dmm method and for the other, i don't know how the other method would out but it doesn't seem accurate. emailed vibe and they only suggest the by ear method and to use it bridged would require an oscilloscope and such that i just don't have. the local shop apparently just got a scope and training on how to do it, but i'd rather not go that route. my guess would be for maybe 30% more than what they would charge, i could buy my own scope. i've used my ears in the past and thus far haven't screwed anything up. i just want to be sure my mids are getting plenty o' powa.

    just thought i'd bring this question over this way since a more educated crowd seem to be here. i'm somewhat surprised no one else has brought this up since it seems to me that a lot of people bridge four channel amps.
    i should really stay off of forums after a few drinks.

  2. #2
    Founding Member
    Join Date
    Aug 2010
    Posts
    496
    What's wrong with the DMM method? Doesn't give you a clipping indicator, but makes sure the gain per side is equal.

    Also, what's wrong with your current method, why change now? It was recommended by the manufacturer and is familiar to you as well. Seems like a reasonable solution as well.

  3. #3
    Member hottcakes's Avatar
    Join Date
    Sep 2010
    Location
    Dixon, IL
    Posts
    77
    i do not know how to use my current method for setting the gains for the thing bridged to begin with, that is the issue. sure i know how to connect all the wires up, but each channel has a gain pot. so that means a front and rear gain for each speaker when using it bridged. how would i go about doing that? i would be willing to test out the dmm method for this application since that would provide the sort of power i'm looking for. however, how would i do that as well since each bridged channel has two gain pots? that and also what frequency would i use for a 6.5 used for 63hz to ~5khz?
    i should really stay off of forums after a few drinks.

  4. #4
    Founding Member
    Join Date
    Aug 2010
    Posts
    496
    you use either pink noise, or really any frequency would work. The goal isn't to set the voltage to a particular value, but rather to the SAME value.

    You can ballpark it by ear if you want to get yourself nearly there. That way you'll know about where you want it to be. Then match them up using the DMM and tones or noise and then check the overall gain with respect to system integrate. Adjust as needed.

  5. #5
    Member hottcakes's Avatar
    Join Date
    Sep 2010
    Location
    Dixon, IL
    Posts
    77
    i really, seriously, try to not come off as retarded, stupid, lazy, or just plain dumb. honest to goodness. but i still just don't grasp what you are saying specifically.

    so i have all rca's unplugged except for the one which i have split using a fancy y-splitter going into the amp on, oh say, rear left and right. i then run the wires accordingly from where i am supposed to and hook 'em up to the dmm. so i'm using rear right positive and rear left negative to the respective leads on the dmm. and i play the pink noise. i do trust you being familiar with the bottom of the litebox4? so i have the two gains to play with. should i just crank one up and match things up for the front bridged channels or should i try to turn them (left and right for rear) up as even as i could and repeat for the front bridge?

    perhaps this is just retarded logic, but what if i connect the rca's in normal stereo (no y-splitter) and run the pink noise while looking for the voltage for a 2ohm load?
    i should just pony up for a t600-2.
    i should really stay off of forums after a few drinks.

  6. #6
    Founding Member
    Join Date
    Aug 2010
    Posts
    496
    Just wire up EVERYTHING like you would to run it. Then disconnect the bridged speaker and set the DMM to volts when plugged into just one side of the bridged outputs (you'll repeat on the other side).

    Play a sine wave. Any frequency will do, you can pick something in the middle of the passband if you like. Read the AC voltage for the sine wave. Should be nice and stable. Say, it's 3.2 volts as an example. Disconnect the DMM and connect it to the other side of the output. Now set the gain so it's exactly 3.2.

    Now plug the spekaer back in and check your system for overall level.

    ----------------

    As a first step, you can just "guess" where equal is (same # of turns for each pot) and get the overall level right. Then match via above and retest. Go straight into fine adjustments.

  7. #7
    Member hottcakes's Avatar
    Join Date
    Sep 2010
    Location
    Dixon, IL
    Posts
    77
    well i'm fairly confident that i comprehend what you mean. thank your for taking the time. i'll have some time this weekend while i wait for some of the paint to dry around here.
    i should really stay off of forums after a few drinks.

  8. #8
    Founding Member
    Join Date
    Aug 2010
    Posts
    496
    let us know how it goes

  9. #9
    Member hottcakes's Avatar
    Join Date
    Sep 2010
    Location
    Dixon, IL
    Posts
    77
    just got in from testing it out. seems to have worked decently, can't say for sure since i only drove around for a few miles locally. perhaps its just me knowing the fact that i changed things around, but near the maximum volume level before i can hear the mid distort it does Seem to have a bit more authority. the only tones i had available at the moment to set things up with was a 100hz @ -3db cd in the car.

    i'll probably leave it in the car as is for a week at the least to see how it behaves with different sources of material. using the same eq cut seems fine, however and maybe its just me, but the stage seems to have shifted to the right (passenger side) just a little bit. so may need to play with the t/a a bit too.

    no immediate issues with the tweeter blending, but perhaps the sub gain may need a bump up. may do that blindly since i have twelve clicks (0-12) of adjustment up front.
    i should really stay off of forums after a few drinks.

  10. #10
    Founding Member
    Join Date
    Aug 2010
    Posts
    496
    good stuff.

Bookmarks

Posting Permissions

  • You may not post new threads
  • You may not post replies
  • You may not post attachments
  • You may not edit your posts
  •