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Reload Thread: Help to find out tuning freq for 2 subs

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    Help to find out tuning freq for 2 subs

    Hello,

    Some months ago I made box for ONE (1) Type R subwoofer.
    I made this box:
    Net Volume: 3cu.ft
    Tuning Freq: 30Hz
    Port Width: 3.25 inch
    Port Area: 40.625 square inch
    Port Length: 35.25 inch
    http://i47.photobucket.com/albums/f2...ll/boxdims.jpg

    Now I want to put TWO (2) Type R subwoofers to same box.

    So how can I calculate what will be tuning freq with two Type R's in this box?
    Port width, area, length will be same.

    It would be great if you could explain how to calculate that tuning freq

    Thanks.



    Car Audio System:
    Head Unit: Alpine CDA-9815RB
    Front: 2 x Alpine SPR-17LS
    Subwoofer: 2 x Alpine SWR-1222d
    Amplifier: Alpine MRV-F545 for components
    Amplifier: Adassa Audio The Warlord for subs




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    Re: Help to find out tuning freq for 2 subs

    2.0-2.5 per 12 @ 33hz would be good...



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    Re: Help to find out tuning freq for 2 subs

    so you want to put 2 type-r's in the same box that you had one type-r in?

    I assume your talking about 12's.

    So basically the only thing that would be different is the .071 displacement of the second sub.

    Comes out to 2.781net@31.1hz. Your initial calculations were a little off or something.




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    Re: Help to find out tuning freq for 2 subs

    2.8 @ 31hz.

    The enclosure's tuning frequency is based on the port area, length, and net volume. The only thing that changes when you add the second sub is the net volume and by a very small amount.

    That enclosure is probably going to lose a little bit of low end and get peaky around 40hz with two subs in it.



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    Re: Help to find out tuning freq for 2 subs

    The minor displacement of the subwoofer added to the enclosure isn't going to effect the port tuning to any great degree that you would notice it.




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    Re: Help to find out tuning freq for 2 subs

    you will notice that the box lacks the low end it once had though... new box time



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    Re: Help to find out tuning freq for 2 subs

    Quote Originally Posted by profundus-sanus View Post
    so you want to put 2 type-r's in the same box that you had one type-r in?

    I assume your talking about 12's.

    So basically the only thing that would be different is the .071 displacement of the second sub.

    Comes out to 2.781net@31.1hz. Your initial calculations were a little off or something.

    Yes I want to put 2 Type r's 12" to same box.



    Car Audio System:
    Head Unit: Alpine CDA-9815RB
    Front: 2 x Alpine SPR-17LS
    Subwoofer: 2 x Alpine SWR-1222d
    Amplifier: Alpine MRV-F545 for components
    Amplifier: Adassa Audio The Warlord for subs

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    Re: Help to find out tuning freq for 2 subs

    Quote Originally Posted by Decipha View Post
    you will notice that the box lacks the low end it once had though... new box time
    WHAT!!!! That's a load of nonsense.

    He'll still have the low end he had before, the addition of the second subwoofer ain't changing the port tuning to any great difference of increase.

    Add the second subwoofer and see how it sounds, then decide for yourself if building a new enclosure is worth the effort, just don't go building a new enclosure thinking that it's going to change any of the bass/performance response from what you have presently.




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    Re: Help to find out tuning freq for 2 subs

    mainly because now two subs are sharing the "3" cubes instead of one in three cubes. take 1 sub in three cubes and one in 1.5 and see how different they sound. i'm not saying it will lose or gain anything, just that it might sound different and you might not like it. or on the other hand you might love it. personally i would build a new box.



    it's a small system.

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    Re: Help to find out tuning freq for 2 subs

    Quote Originally Posted by almond View Post
    mainly because now two subs are sharing the "3" cubes instead of one in three cubes. take 1 sub in three cubes and one in 1.5 and see how different they sound. i'm not saying it will lose or gain anything, just that it might sound different and you might not like it. or on the other hand you might love it. personally i would build a new box.
    OK, in that I would agree 100% given the volume is now split for two sub's and the output is definitely going to increase along with the F3 of the sub/enclosure.




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    Re: Help to find out tuning freq for 2 subs

    Quote Originally Posted by Decipha View Post
    you will notice that the box lacks the low end it once had though... new box time
    Well I could agree with you. I will lose low notes. So this mean that box will be tuned higher. This is what I'm seeking. I want to make SPL box
    It was SQ box because was tuned low and was playing low notes. And if I put second subwoofer I will lose low notes. If I lose low notes it will mean that box tuned higher. Agree?

    But I don't believe that tuning freq will increase only to 31Hz...

    Are you guys sure that only subwoofer dispacement will affect tuning freq?



    Car Audio System:
    Head Unit: Alpine CDA-9815RB
    Front: 2 x Alpine SPR-17LS
    Subwoofer: 2 x Alpine SWR-1222d
    Amplifier: Alpine MRV-F545 for components
    Amplifier: Adassa Audio The Warlord for subs

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    Re: Help to find out tuning freq for 2 subs

    Quote Originally Posted by Beginer View Post
    Well I could agree with you. I will lose low notes. So this mean that box will be tuned higher. This is what I'm seeking. I want to make SPL box
    It was SQ box because was tuned low and was playing low notes. And if I put second subwoofer I will lose low notes. If I lose low notes it will mean that box tuned higher. Agree?

    But I don't believe that tuning freq will increase only to 31Hz...

    Are you guys sure that only subwoofer dispacement will affect tuning freq?
    The port tuning is effected by the Net Volume, Sub Displacement, Port Size and Length, plus any other displacements = Port Tuning.

    Change any of these and your port tuning changes, by how much depends on which program you used to design the enclosure to get the spec's.




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    Re: Help to find out tuning freq for 2 subs

    your tuning will still stay the same, but your frequency response will change. 3 cubes at 30 hz will have a different responce than 1.5 cubes at 30hz. it depends on the sub. try playing with winisd to see how the different volumes affect the response curve.



    it's a small system.

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    Re: Help to find out tuning freq for 2 subs

    the box won't be tuned higher but it will probably peak higher because of the smaller port gain(which is centered at tuning frequency) of 1.5 per sub instead of 3 per sub.

    You probably will lose some low end, but you'll also probably get a flatter response than before as well.




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    Re: Help to find out tuning freq for 2 subs

    Yeah, but he's not going to lose enough low end that he'll notice it and as for a slight high peak, of course he's going to get a dB gain just by adding a second sub.




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