Question about Vas

Discussion in 'Archived Threads 2001-2004' started by Walt Park, Dec 5, 2002.

  1. Walt Park

    Walt Park Stunt Coordinator

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    Ok... so I bought a PE 10" titanic kit, and it just kicks my Polk PSW 350's @$$ all over the house. So... I'm thinking... Can I just get another 10" titanic driver and put it in the polk box. (I want to use the Polk, or at least it's box and plate amp in another room)

    The titanic kit box is 13x13x12 inside. The Polk box is 14.5X13X12 with 2 ports, (should have measured them last night, but it was getting late). So I was thinking of plugging the ports and putting a 10" titanic in there and maybe filling to change the internal volume to be the same as the dayton kit.

    Anyway I was looking at the PE site and looking for possible alternative drivers. I'm new to all this, and was looking at the numbers. Calculating the Dayton kit volume comes to 1.17 cubic feet not excluding any space the driver, plate amp transformer, and the brace volume. The Polk box is 1.31. The Vas for the titanic 2 driver is 1.35 cubic feet. I'm assuming that the 1.17 is calculated for a reason that I lack the knowledge or tools to measure. Is it a fair assumption that I can just use an extra .18 cubic feet of filler in the Polk box, slap a 10" titanic in, and expect a similar sound (assuming I plug the ports)?

    How is the ideal volume calculated if the Vas number is not it, and it doesnt include any of the driver or plate amp volume?
     
  2. Javier_Huerta

    Javier_Huerta Supporting Actor

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    Hmmm... you should better make sure the plate amp of the Polk is not correcting for any deficiencies in its driver. I don't think commercial plate amps are flat - they are equalized to suit the particular driver.
     
  3. Will Orth

    Will Orth Stunt Coordinator

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    Vas= Vase minus that water...lol
     
  4. Chris Carswell

    Chris Carswell Supporting Actor

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    Hmmmm........
    This might be real tricky but, since you ALREADY HAVE the 10" titanic driver in the other box, why don't you take it out & put it in the Polk box so you can experiment with it?
     
  5. Mark_E_Smith

    Mark_E_Smith Second Unit

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    I modeled it on BassBoxPro and I doubt you could hear the difference. Daytons box has a Q of .613 and the Polk box has a Q of .598. Sounds like a plan. Or if you wanted to be wild you could use 1 2" X 7" port, for an F3 of approx 34 Hz box tunning Fb would be 28 Hz. If it didnt work out plug the port.
     
  6. Walt Park

    Walt Park Stunt Coordinator

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    Thanks for the input Mark. Is there a way to tell if the Amp is boosting somewhere? If it is, maybe I should just get another kit. The Kit's cabinet is built alot better than the Polk cabinet, but I'm not sure I'd hear a real difference. The polk box isnt terrible. The port tubes on the inside are oddly made with some kind of decently finnished wood veneer obviously recycled off of some scrap pieces.
    I did try putting the titanic driver in the polk box, but I didnt want to drill the mounting holes until I checked here. I couldnt tell if it sounded right because the driver wasnt screwed in. If the amp is not flat I'm not sure if I'd be better off selling it and buying the kit or trying to salvage the box. I'm pretty sure Polk isnt going to give me the schematics, and I'm not sure I want to figure out where to de-solder to remove any boost. Is there any way of knowing if it's boosting somewhere to optimize the crappy driver? (It is a a crappy driver [​IMG] )
     
  7. Chris Carswell

    Chris Carswell Supporting Actor

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    Your best bet is to contact polk. Maybe you'll get lucky & some tec guy who responds to your email will have some answer for you. If the drivers holes aren't too far off I would say line up as many holes as you can then drill the rest. Then play a sweep or selected tones & measure the response with a SPL meter. Compare the results to your original Titanic box. If it sounds real bad or falls off sharply after say ~30 Hz you have a good idea of what you got to work with. Put the old driver back in so it covers the newly drilled holes & list that bad boy on ebay [​IMG] May the force be with you.
     
  8. Walt Park

    Walt Park Stunt Coordinator

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    heh. I wish it could be that clean. The original driver is 10" edge to edge. The inset is exactly 10". The Titanic driver is like... 11.something. The screw holes need to be out about 1/4 to fit. If I stuck with the titanic, it would be fine cuz the old holes are under the rubber gasket, but if I go back the new holes will be very... evident :|
     
  9. Mark_E_Smith

    Mark_E_Smith Second Unit

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    Ya know if you could get $150 for the Polk you could buy a PE plate amp and build another box.

    Also if the Polk was vented it might not have any boost as that is the purpose of the vent.
     

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