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Thumpper

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Posts posted by Thumpper


  1. thanks trink40.gif ​

     

    unfortunately I spent most of my day stuck on the side of the highway between cities waiting for

    a tow truck.... the company truck decided to shread a belt ...lost power steering , brakes , alternator

    and water pump all at once


  2. I can tell you what phone NOT to get....

     

    I recently got a Samsung S6 Edge for both my wife and I

     

    at first I thought they were awesome until I started traveling or work , between cities the cell reception

    was almost non existant as well as a weak signal in any building I entered

    the video chat quality was really bad , my wife and I eventually gave up on even trying because of the

    crappy picture quality and being constantly kicked off while the phone searched for a network

    ..it was basically useless as a wifi hotspot too for both the laptop and xbox

    I also had to resend many texts that would go un delivered even with 3 or 4 network bars

     

     

     

    I had the Samsungs for almost 2 weeks and took them back , traded them in for iPhone 6's

    everything works flawless on these things....very happy


  3.  

    that's a really small space to put any serious port area into

     

     1.0cf3 tuned at 33hz and a 4" PVC port you would have 27.92" of length to deal with    I would not tune any higher...

     

     the port velocity would be just over 15% ..there would be a little bit of port noise

     

     a slot port would work for that but to get the required port area it would probably go right up to the rear deck and  wrap

    up onto it and shoot towards the  rear window...if I had the car here I could design something

     

     

    you could do some research on some good shallow mounts .......or  go sealed Doh.gif ...I personally stay away from both

     

    Currently using supposedly some of the best shallow mounts for sealed boxes onthe market, the BM MKIV from Stereo Integrity. I like the way they sound and they dig pretty deep, but just not loud enough, which I knew would probably be the case before trying them out. I just wanted to see how they sounded. Now I want more :-)

     

     

     I never liked the performance of shallow mount

     building up to the rear deck and shoot the port back to the window would be my goal


  4. that's a really small space to put any serious port area into

     

     1.0cf3 tuned at 33hz and a 4" PVC port you would have 27.92" of length to deal with    I would not tune any higher...

     

     the port velocity would be just over 15% ..there would be a little bit of port noise

     

     a slot port would work for that but to get the required port area it would probably go right up to the rear deck and  wrap

    up onto it and shoot towards the  rear window...if I had the car here I could design something

     

     

    you could do some research on some good shallow mounts .......or  go sealed Doh.gif ...I personally stay away from both


  5. i wish you could hear my front stage...a SINGLE pair of 6.5" components with 640w rms per channel

    it's crystal clear and stays ahead of my two 12" subs very nicely....staging is awsome

     

    my ground pounder had only two 6.5" mids and a tweeter in each door that kept up to four 15" Xcons easily (800w rms per door)

     

     

    listen to M5....stay away from SMD install photo's  if you want it to sound good... a door stuffed full of assorted drivers 

    gets loud.......but sounds like shit as far as staging and SQ


  6. sometimes bigger is not better.... personally I would go with a pair of ported 10"

    wedge the enclosures towards the center and give the subs a V formation

    so they do not pound into the seat and muffle out

    use PVC to port (save space) and up fire them on the outside of the enclosures

     

    the build will be a bit tricky with the angles but the sub will have room to move air and the ports will have no restriction

     

    sorry for the shitty drawing...took about 30 seconds with a dull pencil..LOL

     

    img054


  7. when putting on a dust cap wear latex gloves.........

    all you have to do is touch the sanded surface of the dust cap with oily/sweaty skin and it will come loose

     

    before gluing wipe the cone surface with  99% Isopropyl as well as the dustcap before it is sanded

    ...they will never come loose

     

     

    I also make a handle out of masking tape and stick it to the center of the dustcap so I have

    something to hold on to when I drop it into place


  8.  

     

     

    from what I can tell the subs are split apart by a double screen door brace and the port

    ( say good bye to acoustic coupling ) ...you just lost up to 3db right off the bat before you even turn the subs on

     

     

    Kind of a misleading statement...  The drivers could be completely dis-coupled (as you state it) and loose zero net output if there are no phase differentials...  It is simply about phase issues between drivers, that is rarely an issue if the box is somewhat symmetrical...  In a properly build enclosure, there is never any output gained by common airspace, the only exception being minimum vent dimensions...

     

     

    not completely

    I made that statement after years of testing with a termlab  , I'v even  built removeable baffles so I could test the difference with the

    subs together and apart  , the improvement is not always dramatic but I always get better results with the subs almost kissing each

    other in the same cavity 

    the old school rule of thumb is to be with in a voice coil diameter of each other but I try and keep them about an inch apart

     

     

     

    Mutual Coupling of Loudspeakers

    Mutual coupling of two or more loudspeakers occurs then they are reproducing th same signal with their acoustic centers close together and pointing in about the same direction at wavelengths smaller than the distance between the two centers. The combined sound signal is propagating forward like one single waveform, the two or more smaller drivers behave like one larger one. 

    The centers of two loudspeakers must be close enough together between 1/4 wavelength and 1/2 wavelength. The higher the wavelength the shorter the necessary distance between the two centers to build up mutual coupling. 

    The actual effect is always direction depending because of cancellations off-axis. Actually (theoretically) the coupling exactly on-axis occurs always independent of the spacing. At smaller wavelengths cancellation occurs earlier off-axis. At longer wavelengths the angle off-axis without strong cancellations is larger. The mutual coupling should be seen a an effect of the average sound level on-axis and off-axis. The acoustic centers' distance and the wavelength of the signal actually determine the angle over which mutual coupling occurs.

    mutual-coupling3.jpg no mutual coupling with acoustic centers 

    more than 1/2 wavelength separated mutual coupling with acoustic centers 

    less than 1/2 wavelength separated

    With two loudspeakers next to each other at a distance of more than the wavelength of the reproduced frequency the average measured volume on-axis and off-axis adds up for +3dB (double power). With two loudspeakers close enough to get mutual coupling the volume adds up for +6dB. 

    Because of the physical size of loudspeaker chassis mutual coupling always occurs only at frequencies below about 500 Hz.


  9. I don't think it is fair to ask for your money back. It is however fair to make sure they deliver what you paid for, but I also think you may have misled them a bit in that regard. I've NEVER seen a shop not at least try to build what was asked for. Sure they might fail often, but the key word was try. In this case I think they built what you asked for. Not quite sure how it could be so confused otherwise.

    You are also probably in the wrong mode of expectation for what you can get out of the drivers you have. They aren't magic...

     

    not Magic....

      I modeled them with multiple tunings and volumes.....they are not a really low digging sub

     

    after modeling that enclosure , with the port velocity I doubt there is port noise I am almost thinking there

    is some rattling going on in the hatch area that is keeping up with the output of the subs ..your problem might not be the enclosure

     

    I would be doing some sound deadening asap

     

     

    the shop should at least fix the carpet and the trim peice...I'm pretty shure if you asked they would add to the port and drop the tuning

     

    if you want to drop the tuning to 30hz add 3.8 inches to the port length


  10.  there is not much more that can be done with out physically listening to it

    I have built enclosures for Exterra's and had no issues with cancellation or distortion off the hatch

     

    I would take it up with the shop you got it from and make them listen to it and see if they will deal with it 


  11. that new pic shows a double baffle with a top trim peice , that changes it a bit

     

    inner volume is now 7.998cf3  , take off sub displacement .34 and port displacement .486

     

    that leaves you with 7.172cf3

    take off slightly more for the window brace and peices glued to the walls

     

    your tuning is 33hz and the port velocity isn't really that bad , here are a couple screenshots

     

    I put it thru 3 different programs ..the velocity was slightly different but we will go with the new Termpak

     

    20150515W9M000000000000000000000000FF0F95BBB0C0P0013

    20150515W9M000000000000000000000000FF0F95BBB0C0P0012

     
     
     
    I do not like the way the subs are seperated by that  double window bracing and port ,
    that's just  stopping  the subs from efficiently cupping the interior volume
     
     
     
     

     


  12. oh my...............

     

     

     

     

    from what I can tell the subs are split apart by a double screen door brace and the port

    ( say good bye to acoustic coupling ) ...you just lost up to 3db right off the bat before you even turn the subs on

     

    the subs should have been mounted with in a voice coil diameter of each other with no restrictions between them 

    so they could CUP the inner volume together with out fighting turbulance

    the entrance to the port has no 45* on the outer wall and there is verticle and horizontal bracing at the port opening

    and it is kind of boxed in

     

    with the high port velocity and the way they have constructed the interior the port noise must be just awfull 


  13. Box:

    Depth: 21"

    Width: 41 1/2"

    Height: 19"

    Port:

    Depth: 12"

    Width: 7 1/4"

    Height: 7 1/4"

     

     

     

     

     if he used 3/4" material you should have about 7.88 cf3 after you take off the port ( .4861cf3  ) and sub displacement ( .34cf3 )

    and you should be tuned at about 31.47hz ............... providing there is no bracing eating up any CF3

     

     

      BUT.............................

     

     

     

     

     

     

     

     

     

     

     

    your port Velocity is about 13% ........

     

     

    I suspect the slope on your 25hz sub sonic filter is leaning towards 30hz too ...... don't expect much

    low end extension with that thing in the way 

     

     

    if those measurements are  correct you have more port noise than anything.......

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