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EV SP8B Speakers

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  • EV SP8B Speakers

    Hey folks, I found a pair of EV SP8B's at an estate sale that were in excellent shape. I understand they sound great and I want to build a pair of enclosures for them alone with no other unnecessary components, but I don't know where to start. I have cabinet making skills and I am mechanically inclined, but know nothing about speaker enclosure design or specifications. Can someone help me with a simple design that will make these speakers sound great like proper dimensions, port size, or any other structural requirements? Thanks!

  • #2
    Here you go. Go to post #3:


    "For a 45 Hz 3 dB down point, they specifiy 1.47 cu ft, a port of 8.7 sq in with a duct 4.4" long. You can go deeper than that, but it would tend to throw the midrange and bass out of balance on peaks.

    For optimum midrange you would want to go a little smaller, with a 60 Hz down point: .738 cu ft, a port of 7.7 sq in, with a duct of 5.4"

    If you want to use it as a full range and want deepest practicable bass, 31 Hz 3 dB down point, they suggest 3.69 cu ft, 10.3 sq in and 3.8 length, but I believe you would be sacrificing midrange quality for that, and it would be out of balance on orchestral peaks and such (the bass would seem to disappear)."


    You are probably interested in the last paragraph - using it as a full range speaker. That will mean building a cabinet that is 3.69 cubic feet interior volume, and a port that will yield 10.3 square inches (such as 2" x 5") and has an interior extension that takes the port 3.8" inside the cabinet.

    Hope this helps.



    • #3
      To be honest, if I was in your position I would "start from scratch", e.g.

      ​1. Use Room EQ Wizard (free s/w) or something similar to measure the driver's t/s parameters and obtain its impedance curve
      ​2. Use Room EQ Wizard and a decent mic to measure its frequency response about 500 Hz or so in a temporary baffle.
      ​3. Use Room EQ Wizard to measure its distortion at various output levels.
      ​4. Use the information from steps 1 and 3 to determine the best alignment (box size, sealed or vented, etc.) for the driver
      ​5. Use the information from steps 2 and 3 to determine if it would be best used full range, or with a tweeter to extend the response at high frequencies
      ​6. Use the information from steps 1 and 2 to design a filter or crossover for the driver.

      Brian Steele