Got some noise from my Blueprint 1503...

Discussion in 'Archived Threads 2001-2004' started by Shawn Solar, Aug 5, 2002.

  1. Shawn Solar

    Shawn Solar Supporting Actor

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    And it sounds like its coming from the port. I didn't get my pro-amp hooked up(technical glich[​IMG] ) But me not being able to wait to hear it and to check for leaks I hooked it up to my 300watt amp. I played a 20hz sinewave and turned up the volume. I got this horrible noise. It sounded like a leak so I took the driver out(not easy) and sealed it good and reinstalled it.
    The second time I still have the noise but listening closer it sounds like it is coming from the port. The sub is in a 160l enclosure with a 6" port, 28" long not including the 6" port flares. I can't believe it is coming fron the port with only 300watts and my sub has a 1/4" bead of silicone underneath and around the perimeter. Is this right can I have audible noise from the port at such low volumes?
    Also, I didn't use PVC or sewerpipe but sonotube for the port. It doesn't fit tight as it should but I've got it pretty good. It has a slight edge could that be it. And lastly If it were a leak would I hear it at all all frequencies? I only hear the noise at 20-26hz. Any help?
     
  2. When I had leaks, it was only at low frequencies when high air volumes are being moved. Older designs with the 1503 and HE15 used 6" ports WITH big aeroport flares.
    I just modeled that setup, and you are at 15m/s at 20hz and it peaks at 16hz with ~22m/s air speed. You might be hearing some port noise but nothing like you seem to describe.
    The only other things I can think of is your amp starting to clip, foam or insulation "riding" on the cone", or maybe your internal wiring starting to slap on the cone.
    I don't know. Sorry.
    (note, even MINOR air leaks can cause significant noise! be very sure that there is no air leaks besides the big leak out of the port [​IMG])
     
  3. Shawn Solar

    Shawn Solar Supporting Actor

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    I think Tomorrow I'll go over it with a fine tooth comb. Or another bottle of silicone[​IMG] I still gonna find some PVC pipe and see if that'll fix it. Just don't want to have to buy 8ft of the stuff. Though I'm still not sure if I ended gettting more silicone on myself. How did you seal your driver? Did you use that gasket? Cause I just about threw the thing out the window.
     
  4. I used the gasket. That with 8 T-Nuts worked like a charm. You can also use weather stripping with excelent results 1/2" wide foam 1/8-1/4" thick with 1 adhesive side.
     
  5. ThomasW

    ThomasW Cinematographer

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    I through the rubber gaskets away, and seal the drivers with thick neoprene (closed cell) foam tape.
     
  6. Shawn Solar

    Shawn Solar Supporting Actor

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    Both of those are good ideas. Just wondering which side those lock nuts go on. The side of the driver or the inside of the box with a hole drilled straight through? Cause I think I migt of put them on the wrong side.
     
  7. They go on the inside of the box with the teeh facing the driver. That way when you tighten the bolts down, it keeps the teeth dug in rather than forcing them out of the wood. Some people have problems with the teeths stripping through the MDF so they use a plywood layer on top of the MDF for the teeth to dig into. I juse use MDF but use gorilla glue to make it perminent.
     
  8. Shawn Solar

    Shawn Solar Supporting Actor

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    Ok then its official I put them on the wrong side.[​IMG] Actually I did'nt realize I had the plug turned upside down when I hammered them in. I've found an air leak about the size of a pinhole near one of the threaded rods that double as legs. I just sealed that and hooked up one side of my pro-amp(600w @ 2ohms) and the noise is not near as bad, so I think I might of been clipping the other amp. I will take some spl readings from both amps after the leaks have been fixed.
     

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