Shiva recomendations/ I am upset

Discussion in 'Archived Threads 2001-2004' started by Kevin Beck, Jan 21, 2001.

  1. Kevin Beck

    Kevin Beck Stunt Coordinator

    Joined:
    Jan 4, 2001
    Messages:
    249
    Likes Received:
    0
    Trophy Points:
    0
    Hey folks,..
    Hows things? Been buss building a pair of Shiva's in sonotubes. Finished them up today.Boy am I upset. I built the enclosures to the specs Adire gave me. 4 ft. enclosure. Tuned to 22 hz. using recommended 17"/4" port.
    Here is how it went,....Hooked everything up. Plugged in the power cord for the first amp. POP! Hmmm, what the heck? Everything is off. Leaned over to plug in the other one. Crack, pop, sizzle,...first amp gone. Second is ok, so I played a couple chapters of Air Force One,....This thing bottoms out so easy its ridiculous. Doesn't sound too bad, but there just isn't the output I expected. Not even close. I don't think I was expecting too much. The PB12's I have been running have as much or more output. Granted, I can't play them both right now! But from spending time with the PB12's, I would say I just spent one bunch of $$$ and a heck of a lot of sweat, for very little.
    Man,....Sunday night too,...Have to go to work on Monday, and stew about this all day, until I get a response from Adire. Now I'm sure they will replace the amp, but that doesn't do much for the performance of the subs. So,...question to anybody that has been there done that! with the Shiva's,....Just how can you squeeze some real punch out of these Shiva's?
    Sorry for the lip flapping, but dagumit!
    4 cu. ft. enclosure...
    17"/4" port...
    Adire Shiva...
    Adire 250 watt amp...
    Amp is set at 1/2,..receiver crosses over LFE at 100 hz.. I feel that's too high, but until my new receiver comes in, I can't do anything to change it.
    Guys I need help on this one. From everything I have read, these subs can really kick it out. Something must be wrong.
    Thanks Kevin,...>>>--->
     
  2. TerryC

    TerryC Stunt Coordinator

    Joined:
    Oct 19, 1999
    Messages:
    218
    Likes Received:
    0
    Trophy Points:
    0
    Do you have a SPL meter? If you do position it one meter from the sub and tell us how loud you are getting where it bottoms.
    Have you checked for air leaks? If you have a nerf football or blow up beach ball they plug the ports fairly well so you can listen for leaks.
    What is your receivers sub out level set to? +/- what?
    Terry
     
  3. Kevin Beck

    Kevin Beck Stunt Coordinator

    Joined:
    Jan 4, 2001
    Messages:
    249
    Likes Received:
    0
    Trophy Points:
    0
    Terry,..
    Hey,..just checked back before I logged off. The enclosure is tight as a drum. I am going to borrow an SPL meter from a guy if I can get in touch with him tomorrow. The sub is just not all that loud. It has just a touch lower response that the JBL"s, but with a heck of a lot less output.
    Thanks Kevin,...>>>--->
     
  4. Craig R

    Craig R Auditioning

    Joined:
    Nov 24, 2000
    Messages:
    9
    Likes Received:
    0
    Trophy Points:
    0
    Running the Shiva numbers through BassBox Pro 6, I come up with a 3.7 cuft box tuned to 21hz. Basically the same as your 4ft box tuned to 22hz. So the size/tuning looks right. That's assuming you have the voice coils wired in parallel or in series.
    If you only used one voice coil you would need a 17 cu ft box. You can wire them in series or parallel without changing the box size/tuning. Only thing that changes is the sensetivity, parallel is 6dB more sensetive than series.
    Are you sure there are no air leaks in your enclosures?
    Assuming your drivers specs are close to the published specs, in a 4ft box tuned to 22Hz a 250 watt amp should not be able to bottom out that driver. It would take 200 watts at 32hz just to reach the drivers max LINEAR excursion but there is still a long way to go before you reach it's max physical excursion. To hit the max physical excursion of 22mm at 32hz would require 800 watts.
    Unless the drivers are miss-wired, or the box has an air leak, I would guess you are hearing the amp clip and not the driver bottoming. Or you got a defective driver.
     
  5. Brett_A

    Brett_A Stunt Coordinator

    Joined:
    Dec 18, 2000
    Messages:
    109
    Likes Received:
    0
    Trophy Points:
    0
    It sounds like you have the speaker wired wrong. I would double check that first.
    ------------------
    Brett
     
  6. BrianW

    BrianW Cinematographer

    Joined:
    Jan 30, 1999
    Messages:
    2,563
    Likes Received:
    38
    Trophy Points:
    0
    Real Name:
    Brian
    One possibility is that you have your voice coils wired out of phase with one another. Although this shouldn't cause an amp to blow, it would seriously diminish output.
     
  7. John E Janowitz

    John E Janowitz Second Unit

    Joined:
    Oct 30, 2000
    Messages:
    445
    Likes Received:
    0
    Trophy Points:
    0
    Kevin,
    One problem I see is with the vent velocity and copression you will get with a single 4" diameter port that long. You will likely have alot of audible vent noise and the port compression will greatly limit your output.
    As others said, you may have a problem with your wiring. If only one VC is hooked up, you will get very little low frequency output in this enclosure.
    As far as bottoming the driver goes, the models for excursion do not take into account "overshoot". In a perfect world a driver's excursion would be equal to what is modeled. In reality though since a driver's suspension is not a perfect spring, this is not the case.
    John
     
  8. Kevin Beck

    Kevin Beck Stunt Coordinator

    Joined:
    Jan 4, 2001
    Messages:
    249
    Likes Received:
    0
    Trophy Points:
    0
    Hey guys,...
    If a single 4" port will limit output. What would be the better arrangement to equal the same tuning?
    Thanks Guys,...Kevin,...>>>--->
     
  9. Jason J

    Jason J Auditioning

    Joined:
    Feb 21, 2000
    Messages:
    9
    Likes Received:
    0
    Trophy Points:
    0
    Kevin,
    I built a dual shiva sonotube this summer and am only feeding 125 watts to each sub, with voice coils paralleled on each. Mine performs amazingly, so I think this is almost surely a case of (1)user error...Don't take it the wrong way, but it sounds like you've seriously got something wired incorrectly. or (2)a defective driver. Tell us exactly how you have it wired, ie. where every wire goes, polarity, etc. and let's see what we can figure out.
    Jason
     
  10. Kevin Beck

    Kevin Beck Stunt Coordinator

    Joined:
    Jan 4, 2001
    Messages:
    249
    Likes Received:
    0
    Trophy Points:
    0
    Jason,...
    I come from Car audio,..so I hope I'm not just expecting too much,...I'm not use to tuning subs to 22hz, let alone some of the 17, 18 hz units I see some folks have built.
    But here goes.
    I have an 18" sonotube 33" long, 1.4" caps on each end. That leaves 30" inside length.1 Shiva Driver on the bottom, port on top. 1-4" port, 17" long. I have the 250 watt Adire amp running the driver at 4 ohm load. Coils paralleled. Positive to positive, negative to negative. I then have the leads from the amp running positive to positive on one coil, and negative to negative on the other coil. Don't jump me here. Some people do it this way, some wire off one side. This works more effectively when running coils in series, but it works for parallel too.
    The tube is sealed up tight. I have tried the stuff, push, and rest trick, Dan at Adire recommends to check for leaks. It comes out fine. I have run the amp from 1/2--1/4. all other levels at 0. Still on some material,..crack pop, pop.
    I am going to get this thing over to a friends place on Friday, and run it in his system. He has a much better receiver than I do at the moment. Without a way top check the amp,...I am left with suspecting the receiver sending the sub a dirty signal....Any thoughts on that?
    Thanks again for the help,...I'm baffled,...Kevin,...>>>--->
     
  11. TerryC

    TerryC Stunt Coordinator

    Joined:
    Oct 19, 1999
    Messages:
    218
    Likes Received:
    0
    Trophy Points:
    0
    Kevin,
    Coming from car audio to home is a disappointment in subwoofer performance. Very slim chance you can get the pressure one can get in a car without tons of drivers or a very tiny room.
    I asked way up top, what is your receivers sub level set at? The reason I ask, it its set anywhere near 0db or even -2db you can get clipping from the sub pre out. Set your sub amp volume to the 2/3 to 3/4 full mark and hopefully your sub level in the receiver can be turned down but still get the same level as before. I'd shoot for the -5 to -10 setting.
    Do you have a SPL meter? What SPL level are you hitting a one meter away?
    Terry
     
  12. Kevin Beck

    Kevin Beck Stunt Coordinator

    Joined:
    Jan 4, 2001
    Messages:
    249
    Likes Received:
    0
    Trophy Points:
    0
    Terry,..
    Sorry for not picking up on you. I thought I was dead in the water for a bit there. You are right,..I try not to expect too much from the system in terms of chest pounding SPL, but I thought I would get closer than I did.
    The sub out setting on the rec. is at 0. I have run the amp on the sub, from 1/2-1/4. 3/4 is way too much. I guess I didn't think the sub out setting would ever have to be at a negative. I can give that a try. The guy I was going to get the SPL meter from had surgery the other day, so that was out. I may just have to run down and get one for myself.
    Thanks Kevin,...>>>--->
     
  13. TerryC

    TerryC Stunt Coordinator

    Joined:
    Oct 19, 1999
    Messages:
    218
    Likes Received:
    0
    Trophy Points:
    0
    Kevin,
    A single home sub will never compete with a good car system.
    With my Shiva in my convertible car I'm hitting 122db on my Rat shack meter at times when set to fast and I'm sure at those SPL's my meter is off.
    With a closed in coupe a good sub and amp will hit 125-140db with todays high end subs.
    In my home I'm lucky to hit 115db with my single mass 2012.
    Remember a difference of 10db is considered a doubling in perceived loudness.
    Terry
     
  14. Kevin Beck

    Kevin Beck Stunt Coordinator

    Joined:
    Jan 4, 2001
    Messages:
    249
    Likes Received:
    0
    Trophy Points:
    0
    Terry,..
    I tried to back off the sub out setting on the receiver. I ran it at -5. That didn't work either. I am taking the unit over to a friend house tomorrow, and see how it performs pver there. I can't wait. This will be a good test. The only other thing to do, is fire up the new amp for the other sub, when it get here, and see how it sounds,,...
    Again, thanks for the interst,...Kevin,...>>>--->
     

Share This Page