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Quatro 15 Question

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  • Quatro 15 Question


    Okay well since i got my new bed i now have room to put a sub under my bed. I now have room for a quatro 15. I was thinking a 5.5cf ported to 18hz. I am not sure on port size or length. I do know that i want NO port noise. And this box will be like 7.5" tall and the other dimentions havent be determined yet. I will use this sub downfiring. with a port out the side.

    I have a concern about having loss of bass. My room is like 10*8. But it seems like evrywhere i place a sub that i have no bass but then my sub only plays satrong to 40hz or lower. But i have to corner load it to get bass. If i place it anywhere else i lose asll lowend. Is this because of my sub or is my room just a bass robber.

    If all gose planned i will have this thing built soon.

  • #2
    Room Layout


    here is a layout of my room i have posted about this before but never recived any help on the room placement situation...
    <A HREF="http://www.pesupport.com/cgi-bin/config.pl?read=269240">http://www.pesupport.com/cgi-bin/config.pl?read=269240</A>

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    • #3
      In my new layout the tv and couch are swaped *NM*



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      • #4
        Re: Quatro 15 Question


        Don't downfire it. It'll work for a while, and then you'll be all disappointed.


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        • #5
          Re: Quatro 15 Question


          I dont see how, acording to my math it is only .3mm away from being downfire capable

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          • #6
            Re: Quatro 15 Question


            Okay. Go ahead. But it'll be more prone to have problems around that area.

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            • #7
              Re: Quatro 15 Question


              > Okay. Go ahead. But it'll be more prone to
              > have problems around that area.

              I wasent arguing with you, i was kinda asking. Why do you think i may have problems later? I didnt realise that .3mm was a big deal.

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              • #8
                Re: Quatro 15 Question


                IIRC, the "can you down fire it" bit has to do with cone weight and suspension stiffness, coupled with motor control. The Q15 is borderline, which means that you might have problems with it. Something on the order of... instead of excursing 9mm-9mm, you'd get 12mm (down) and 6mm (up).

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                • #9
                  Re: Quatro 15 Question


                  Wouldn't it simply sag from side to side if you side fired it, then? Wouldn't it simply sag in reverse if you top mounted it, then?

                  As I understand, down firing is preferred because it reflects the pulse and fills the area better. Isn't a sub that can't be downfired a significant concession?

                  > IIRC, the "can you down fire it"
                  > bit has to do with cone weight and
                  > suspension stiffness, coupled with motor
                  > control. The Q15 is borderline, which means
                  > that you might have problems with it.
                  > Something on the order of... instead of
                  > excursing 9mm-9mm, you'd get 12mm (down) and
                  > 6mm (up).

                  Comment


                  • #10
                    Re: Quatro 15 Question


                    Top firing = down firing. The two scenarios face the same forces of gravity. Drivers are designed to have free (to a certain extent) movement in one axis so the spider and surround that make up the suspension are manufactured in a way to allow this type of desired movement yet retain stiffness in the axis perpendicular to the axis of movement in order to keep the voice coil centered in the gap. This is why side-firing isn't really an issue when it comes to sag. Gravity isn't exploiting the axis of free movement as it does when the cone is facing up or down. Yes, the suspension will sag a small amount over time on a side-firing driver over the life of the unit but it's nowhere near as much sag as when you have the driver pointing up or down. That said, in order for a driver to be used in an up or down firing situation the suspension as a whole must be stiffer to resist the sagging.

                    Damn, that's just too much thinking at this time of the day for me. I think I need a stiff drink now to bring me down before I head out into the world.

                    shawn
                    My favorite woofer is a Labrador retriever.

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                    • #11
                      Re: Quatro 15 Question


                      > IIRC, the "can you down fire it"
                      > bit has to do with cone weight and
                      > suspension stiffness, coupled with motor
                      > control. The Q15 is borderline, which means
                      > that you might have problems with it.
                      > Something on the order of... instead of
                      > excursing 9mm-9mm, you'd get 12mm (down) and
                      > 6mm (up).
                      Would it help if i side fired the woofer at an angle somthing like 45 degree's?

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                      • #12
                        Re: Quatro 15 Question


                        Trev, do whatever you want with it.

                        If you kill it, at least now you'll know why.


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                        • #13
                          Re: Quatro 15 Question


                          Trevor, what is the maximum vertical dimension you have to fit this under your bed? If you have a whole foot of space to use, then this might work. Anything less will force you to down/top fire, which is not recommended for this driver.

                          Not accounting for the thickness of your enclosure, a 15" driver mounted at 45 degrees would require a minimum of 10.6" vertical clearance. (Using the pythagorean therom- you should know this before going any further).

                          Given the 45 degree angle, if you face the driver outward (away from the wall or other obstruction) you will then have a reasonable amount of space for airflow around the face of the driver. This also means that you can build the box to fit closer to the floor and underside of the bed without worrying about airflow. You could literally size the box to just slide under the bed with almost no clearance.

                          So what you would have is a 6-sided box, similar to a 'truck wedge'. The side with the driver will be at a 45 degree angle to the floor, the other sides will be perpendicular. The bottom will be larger than the top, and two of the sides will be trapezoidal.

                          I would proportion the box such that the baffle is wide enough to accomodate the ports being placed on either side of the driver. Then make the box as deep as you need to reach your intended volume and port length requirements.

                          > Would it help if i side fired the woofer at
                          > an angle somthing like 45 degree's?

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                          • #14
                            Re: Quatro 15 Question


                            Acording to my calcs. I triangle to these specs should work.
                            7.6" deep, 13.5" tall, and 15.5" as the slope lenghth. ANd it should be in between down and up firing.

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