Going to upgrade my Shiva to a Tempest

Discussion in 'Mobile Phones / Entertainment' started by Jack*Mains, Jan 28, 2004.

  1. Jack*Mains

    Jack*Mains Stunt Coordinator

    Joined:
    Sep 25, 2002
    Messages:
    156
    Likes Received:
    0
    For about a year now I've had my shiva in a rather small 1.5cuft box due to space limitations. The sound is very tight, but does not go quite deep enough.

    I've been thinking of seling this sub to a friend and building a new box utilizing the tempest.

    I listen to mostly rock, so the sound has to be tight... but I really would like some deep extention.

    I was thining of making a 155L box and slot porting it to 20-25Hz, and hope the tempest still provides enough punch when I need it.

    The problem I ran into is with the slot ports. According to a few calculations, I would need a cross sectional area of 90sqin to avoid port noise; this would yield a port lengh of over 60inches. [​IMG]

    Would it be possible to cut down on the cross sectional area and avoid port noise?

    BTW: Ive made a small excel spreadshee to help me out with the values, check it out if you wish.

    Port Calculator
     
  2. Matt Odegard

    Matt Odegard Stunt Coordinator

    Joined:
    Nov 5, 2002
    Messages:
    212
    Likes Received:
    0
    Keep it sealed and make your box larger. You don't necessarilly have to have it ported to go low although it does help. Sealed will be tighter but less efficient, but your looking for sq it seems to me and not spl so stick with sealed.

    It's all in the box, hell your Shiva should go just as low as the Tempest.

    Build a good box first, then figure out if you need a new sub. You should know 1.5cubes isn't squat for a Shiva. Thats just holding it back.

    If you can't build bigger than 1.5 due to space limitations, you should look at different subs. A Tempest is going to have to be bigger, alot bigger. Tempest's need a good 3.5-4cubes to sound good.

    I don't know what 255liters equates to but I'd stick with the Shiva and a better box first.
     
  3. Jack*Mains

    Jack*Mains Stunt Coordinator

    Joined:
    Sep 25, 2002
    Messages:
    156
    Likes Received:
    0
    Well I do have a large trunk, but Id like to have some room left over.. 255L seems rather exessive. The biggest EBS enclosure for a shiva is only 145L.

    Maybe Il build a ported 100-150L box for it and see how it goes.

    BTW: THe reason for such a small box in the first place is that it was in another car, which had very little room.
     
  4. Matt Odegard

    Matt Odegard Stunt Coordinator

    Joined:
    Nov 5, 2002
    Messages:
    212
    Likes Received:
    0
    I think ported would give you the lowend your looking for and still save some spave over the Tempest. What to port it to? I have no idea, I always take advice for that area, instead of give it[​IMG]

    Check Adire's website or email their CS or Tech department. They could tell you what enclosure will make the most of your sub.

    But, if thats not enough and if you have the room in your new car and wanna have some fun with a bigger sub. Then I'd look at the Tempest.

    HTH
     
  5. Frank Grimes

    Frank Grimes Second Unit

    Joined:
    Jul 19, 2002
    Messages:
    260
    Likes Received:
    0
    Sealed will not sound "tighter" than a ported enclosure. "Upgrading" to a Tempest will give a minimal SPL increase yet will require a significantly larger box, especially ported. I'll second the keeping of the Shiva and simply building a new box.
     
  6. Jack*Mains

    Jack*Mains Stunt Coordinator

    Joined:
    Sep 25, 2002
    Messages:
    156
    Likes Received:
    0
    Alright, I am going to take your advice and build a larger box.

    I just loaded up WinISD and set up a few designs, and you're right: in fact, the shiva seems to be a better choice until you get into the 300+L boxes. Thats just too big even for me.

    Now, i've looed at the different alignments for the shiva, and contemplating between an EBS (what I have at home.. it huge!) and SBB4. Would it be alright to build something in the middle? Say 125L turned to 22Hz. That seems like a good option. How would that affect the equivalent Qtc?

    Lastly, I was planning on using a slot port, would I experience any port noise if I use a roughly 12in * 2in port? I would have to zig-zag it inside the box, as it needs to be 28in for a 22Hz tuning.

    Check out the design:125L Shiva
     
  7. Frank Grimes

    Frank Grimes Second Unit

    Joined:
    Jul 19, 2002
    Messages:
    260
    Likes Received:
    0
    I don't think port noise would be a factor, especially considering this is going in a trunk. Regardless, since you're worried about port length, don't forget about cabin gain+ source material. 22hz really isn't necessary for a mobile environment unless you plan on doing a lot of movie watching.

    125L should result in a very flat FR and high efficiency. Sounds like a great setup, though you may want to check with Adire's recommendations, as I'm sure you know that Mr. Wiggins is always willing to help people out...
     
  8. Jack*Mains

    Jack*Mains Stunt Coordinator

    Joined:
    Sep 25, 2002
    Messages:
    156
    Likes Received:
    0
    Not, not watching movies, just music. (Lots of rock.)

    Should I tune a little higher? maybe 28Hz.
    Seems that would give an extra 3db at 30Hz, but 5db less st 20Hz vs the 22Hz tuning.
     
  9. Matt Odegard

    Matt Odegard Stunt Coordinator

    Joined:
    Nov 5, 2002
    Messages:
    212
    Likes Received:
    0
    28-30hz I think would be good. I don't think too much music goes below 40hz even. Especially rock, but for that added umph that you crave. I'd go to 28-30hz.

    Others can chime in, but it was always my understanding that most bass in music was around 40-60hz. But, I've also been known to talk out of my a$$ so don't quote me on it.[​IMG]
     
  10. Jack*Mains

    Jack*Mains Stunt Coordinator

    Joined:
    Sep 25, 2002
    Messages:
    156
    Likes Received:
    0
    Alright, this is the last call.

    Ive modeled some designes, and came up with a 125L box tuned to 25Hz.

    The dimentions are 14" High, by 16" deep, by 34" wide. I've also desided to go with a slot port. The design calls for a physical port length of 21.96", with the port being 14" by 2". Since the box is only 16" deep, i would have to zig zag the port inside the box to achieve the required length. Should I try to curve the inside edges of the port where it meets the back wall as to make it more round where it curves?

    Can anyone see any problems with this design? And if so, please let me know: Im starting the build in a few days.

    Thanks.
     

Share This Page