2 or 4 mids?

Discussion in 'Speakers' started by Stephen Matthew, Jul 31, 2004.

  1. Stephen Matthew

    Stephen Matthew Stunt Coordinator

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    im building some new mains.. going for a nice low budget setup ...

    my center channel is my main target for sq... it consists of 2 vifa tc 5.25"s and a single vifa MG 1" dome tweet in about .4 cubes sealed.. i love the sound of this.... it replaced a 150 dollar jbl center, and i tested out a boston acoustics center and a 250 dollar polk center channel in a/b swaps and neither could match the vifa combo...


    well.. my mains suck balls...

    soo..

    i picked up 4 of the vifa 6.5" mids on sale at partsexpress right now for 8 bux each... they were made for infinity it says on the back... i also picked up a nice 1" audax silk dome tweet for each cabinet... now im starting to wonder... since im going for something with the same transparence as the center but capable of getting quite loud so i can hear it outside, perhaps it would be better to try running 4 of the mids per... and i guess adding another tweet.. though i still havent listened to the audax tweets to see how i like them....

    system so far consists of..

    HK avr 525 driving my crappy mains, the vifa center, some cabinets i made with some boston coaxes as rear back surrounds and no rear side surrounds yet..

    E12k.44 sealed in a cube off of 200 watts for low end.. so i guess im not too concerned about the vifa's handling the low end too much...

    sooo.. any reviews on the audax tweets? and should i stick with 2 6.5"s and a single tweet per side, or is it worth the extra 70 bux to go ahead and double the number of mids and tweets?
     
  2. John Garcia

    John Garcia Executive Producer

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    Have you built home speaker crossovers before? (car audio?) A BIG part of speaker building is the x-over. If you expect it to work well and sound good, you will need to come up with a decent x-over, and multiple mids is not going to make that easy, IMO. Have you considered DIY kits?

    This belongs in the DIY forum, BTW.
     
  3. Brian Bunge

    Brian Bunge Producer

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    The Adire kits use the 1" silk dome Audax tweeter with the neo magnet. They're great little units. I used to own the big LCC center channel kit and was quite impressed with it.

    And yes, this definitely belongs in the DIY forum.
     
  4. Stephen Matthew

    Stephen Matthew Stunt Coordinator

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    hmm xover.. figured id either get a partsexpress model, or perhaps just go with some car audio passives ive got laying around.. about 5 sets to choose from.. i originally thought 2 mids so i could run 4 ohms to match the center channel... of course now that i think about it.. darn.. forgot about getting 4 ohm tweets.. oh well.. may have to swap tweeters... and yes these are some 1" silk dome audax tweeters.. im sure i can find another use for them either way...


    and how do you know what forum to put this stuff in?? ive gotten it wrong about my last 10 posts.....

    kinda figured this wasnt an advanced question so shouldnt be in DIY and despite me constructing the cabinets, it shouldnt be in construction,.. bah.. im worthless
     
  5. Dan Hine

    Dan Hine Screenwriter

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    Well, in this case you are BUILDING your own speakers. So it would go under the Do It Yourself area. Just ask a mod to move it. [​IMG]


    - Dan
     
  6. Stephen Matthew

    Stephen Matthew Stunt Coordinator

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    hmmm.... ive always figured if you went with a quality xover with quality parts and had an xover point at the right spot you would be fine.. am i missing something to the xover part?

    in the past, ive used a/d/s xovers for most of my generic component sets or home theater cabinets.. they were originally matched up with speakers fairly similar to what ive used them for and the xover freq is within a hundred or so of what ive aimed for generally anyways.....
     
  7. Brian Bunge

    Brian Bunge Producer

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    Using generic XO's does not take into account baffle step, any response anomolies of the drivers, etc. While what you've cobbled together may sound decent, it won't sound as good as it can. Your best bet would be to check out the PE board and see if anyone has built something similar to what you propose or is willing to design something based on the cabinet dimensions you plan to use.
     
  8. John Garcia

    John Garcia Executive Producer

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    No, it's not that you are missing something, just that crossovers are not exactly that simple. You not only have the x-over point, but the slope, and how you achive that slope with x-over design, based on the specific drivers parameters you are using. The components used to make the x-over actually have a large impact on the sound as well.

    To me, the simpler you can make the x-over, the better. I would highly recommend The Loudspeaker Design Cookbook if you are serious about building your own speakers. I don't think you are after audiophile grade speakers here, but a little more research could proably get you some excellent speakers for not much more than you are looking at spending right now.
     
  9. Rory Buszka

    Rory Buszka Supporting Actor

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    I can also speak from experience that without a lot of knowledge of passive electrical filters and computer simulation software, you can't expect your crossover to meet all the needs of your speaker. Sometimes the drivers have funky impedance curves that cause the crossover not to work as well. Sometimes there are huge peaks that you need to take into account. The midbasses I chose featured a convenient (*sarcasm*) 5dB peak at 3100 Hz. Even if I had crossed over at about 2500 Hz, the peak would still be between 3 and 4dB in the response, at the same frequency. I crossed over at 2700 Hz, and when I listen to electric guitars it sounds like they're whistling. Fortunately, I've discovered Audua's Speaker Workshop so I can play around with crossover designs but it takes a lot of work to set up and a generous soul from the DiyAudio.com board already designed me a crossover that has less than +/-1dB variation over the whole frequency range. If you do build a crossover, at least buy a book called The Great Sound Stereo Speaker Manual. My friend who's also into DIY speakers has that book and it's full of information. Read the section about crossovers all the way through. If there's something you don't understand, read it again. Learn how to import text files with CLIO-measured response data into Microsoft Excel and make your own frequency plot. Also, learn about impedance. The impedance of a driver is not simply resistive, as most older crossover-design infirmation assumes. The Great Sound Stereo Speaker Manual gives you pointers for dealing with aspects of the driver's impedance curve in your crossover. The Great Sound Stereo Speaker manual can be ordered from PartsExpress.com and it is worth the price. But jumping into this the way you planned will only lead to disappointment.
     
  10. John Garcia

    John Garcia Executive Producer

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    Even the placement of the drivers in the cabinet relative to each other is of importance. Phase alignment of the drivers, which can be manipulated with the x-over, can make something that seems simple not sound right. Impedance of multiple drivers can also be adjusted for with the crossover network. I thought it was simple too, until I started building my own speakers. IMO, you might want to consider looking at DIY kits that are available, then just build your own cabinets.
     

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