HELP! anybody help w/ completed sub

Discussion in 'Home Theater Projects' started by perry web, Feb 15, 2004.

  1. perry web

    perry web Stunt Coordinator

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    OK.
    I built my sub.
    It is a ported 118L box. port is 4" and 17" long (uncut flared port kit) so it should be tuned to approx. 20.5 hz.
    Driver is a SHiva Mk IV powered by a PE250w amp.

    It is bad! My yamaha 8" sealed sub plays louder.

    It sounds really distorted like it is blown at low levels. If I can get it to go louder it sounds like it is bottoming out hard but what appears to be very little travel. Nothing is hitting the back of the woofer.
    I have tested the amp by powering an old center speaker I have. It seemed to go ok. I had to turn the crossover all the up of course. I tested the driver by hooking up to my main speaker wire. SOunded bad cuz it was not in a box but seemed to function fine.

    I have played w/ the phase, gain level, and the crossover. I have turned the crossover all the way down to the 40hzs and the gain to about 1/3 and still it sounds bad.

    My receiver is couple yrs old. Has a sub pre-out (rca) but no menu to for settings.

    The box is stout. No leaks. The bracing is good unless I have to much. You can see pix here in this thread

    http://www.hometheaterforum.com/htfo...hreadid=184657

    or here at this website.

    http://dodgetrucks.org/cgi-bin/index...pe=2&si=pne123

    it is a 14x12 room centered in the middle of the 12' wall.

    any ideas? please help. my wife is really starting to look at me funny. I really thought I had this nailed.

    thank you in advance.
     
  2. Chris Tsutsui

    Chris Tsutsui Screenwriter

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    Does that Shiva driver have dual voice coils? Make sure you wired them in parallel which is positive to positive and negative to negative. Then hooked it to the amplifier. That may solve the driver's limited suspension movement.

    If not the woofer could be defective. Unplug the woofer and check the suspension of the driver by lightly pressing down on the center of the dust cap and seeing if there's any binding or scratching of the voice coil. I've had a woofer that wasn't in alignment once and it sounded HORRIBLE, and it sounded like it was scratching when I used my hand to physically move the woofer cone back and forth. It should be effortless with no binding.

    Oh, don't press down on only one side of the cone cause that might cause some rubbing. hehe

    Good luck, I know what if feels like to have a project go wrong. I blew up some capacitors when working on an amplifier and got electrolyte fluid all over the place and got to witness a beautiful mini-white mushroom cloud. (The caps were accidentally wired out of polarity)
     
  3. Dave Poehlman

    Dave Poehlman Producer

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    It wouldn't be the first time a driver has been defective. Talk with Adire, they're pretty good about replacing them.
     
  4. perry web

    perry web Stunt Coordinator

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    thanks.
    It is wired correctly...I checked walked away and checked again. Funny haw something that should work doesnt can make you unsure about something has easy as two wires.

    I moved the cone and seemed to be fine. I will get my head closer to it and listen.
     
  5. Michael Hartwig

    Michael Hartwig Stunt Coordinator

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    I don't know if this will help you. But I found in my Tempest with the Adire 250W amp, it played much better when I split the RCA output (with a y-connecter) from the reciever. This y-connecter gives you a feed in to both L and R jacks of the sub amp. The volume increased quite a bit. I find if you go past the 12 o'clock position of the sub amp you'll get an increase in distortion. I plan on getting a much better sub amp with more watts for my Tempest like a Nady XA910. More power is never bad.
     
  6. perry web

    perry web Stunt Coordinator

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    thanks. I am going to go get a y adaptor when radio shack opens. i have the plug in R input like the instruction say.
     
  7. Brian Fellmeth

    Brian Fellmeth Supporting Actor

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    See what happens when you wire up just one voice coil- leave the other two lugs open. Sounds to me like somehow the voicecoils are wired out of phase so that one is opposing the other leaving you with noisy weak excursion
     
  8. Dan Wesnor

    Dan Wesnor Second Unit

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    Air burping out from around the edge of the woofer's frame can sound bad - it doesn't sound like air moving at all. Feel around the rim of the woofer while the sub is playing and see if you can feel any air moving.
     
  9. perry web

    perry web Stunt Coordinator

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    ok, I think I have bad speaker.

    after running it from my receiver it still made the same noise. sounds like a rattling trunk lid on a ricer.

    I removed it from the box, turned down my plate amp. still made the noise at low levels. both voice coils made the noise running seperately and together. The cone is only moving a couple MM

    I was suspending it w/ my fingers so it was not vibrating against anything.

    I guess I will have to return it or am I just completely missing something?
     
  10. ChristopherD

    ChristopherD Stunt Coordinator

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    Adire is very good at replacing drivers. Just drop 'em a line with what you've done to diagnose the issue. Replacement shouldn't be a problem at all.
     
  11. JakubH

    JakubH Stunt Coordinator

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    Perry - I have a similar problem, maybe we can compare notes? I just got a Rava (sealed Shiva + AVA250) sub delivered from my Adire dealer. This sub was on backorder for some time and finally shipped when Adire recieved a new shipment of Shiva Mk IV early in Feb.

    As soon as I hooked the unit up, I knew somethign was seriously wrong. The bass was extremely distorted (sounded like a buzzing rather than clear bass), and the sub made odd rattling noises. Applying a little volume bottomed the driver with maybe a few mm's of travel. This was all at levels that my mains (run full range, 8" Vifa M22 woofers) can handle easily without strain. My first instinct was exactly the same as yours; sounds like a blown woofer.

    So I called my dealer and explained the problem, he said that I'm not the 1st person to call with this problem, and that there was something wrong with this batch of Shivas. Now I have to mail it back, and wait for either a replacement or a refund [​IMG] . Let me emphasize that this has nothing to do with the dealer, he has been extremely helpful, and in this scenario really only re-mails the product within Canada, so the issue is with Adire.

    Needless to say I'm pretty dissapointed, I waited patiently for a month for the sub to ship, even though my CC was charged as soon as I made the order. I guess I was just spoiled by my previous 'online' purchases going perfectly.

    What I'm surprised by is the QA at Adire... I've followed this company for years, since they introduced the Shiva and were called Avatar Audio. They have a sterling reputation. They supposedly test each unit before it goes out the door (I'd hope so, at least for the finished speakers like my Rava), so how could a glaring problem like this be missed? The problem is not subtle, it sounds horrible, pipe organ tracks sound like they're being played through some sort of giant kazoo! I just don't see how a tester could miss it. Its possible that the driver was somehow damaged during shipping, but I find that unlikely as both the enclosure and the double-box they ship in (very nice BTW) were pristine, not a scratch.

    Anyhow, I think you may have a defective driver like I do. I'd call them and get ready to ship it back. Hope you kept the original packaging, I didnt and now have to buy some [​IMG] I'm going to send my unit back this week, as soon as I can convince someone to drive me to a Mailboxes etc. with this thing. I'll keep anyone who cares posted on the results.
     
  12. perry web

    perry web Stunt Coordinator

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    yep, that is how mine sounds.
    I got it from the same batch as you then.
    I am filing out the form now.

    Mine was not double boxed. The label is right on the white shiva box....however, my amp from Parts express was double boxed

    I hope it is not a hassle. If i would have known i would have waited for the titanics that WAS on sale.
     
  13. JakubH

    JakubH Stunt Coordinator

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    perry - I think the double boxing is used only on finished speakers, to protect the finish and due to the weight. The Rava boxed was ~ 70lbs, and quite large. I have ordered raw 12" drivers from Stryke before, and they arrived single boxed and in working order. I think this is more likely a 'bad run' of drivers, which does happen. How the batch makes it through QC out the door is the mystery.

    I don't think you will have any hassle w/ Adire, as others have said they are known for excellent service, and have been were very helpful to me pre-purchase via phone and email. I can certainly sympathize with your frustration though, I live in Canada, don't have a car, don't live near a UPS depot, and have a broken foot [​IMG] Every time I need to move this thing, pick it up, drop it off, etc, I have to ask a friend for a favour. Such are the risks of bargain hunting on the internet though, on the balance I think its worth it. Good luck, and let me know how you make out.
     
  14. perry web

    perry web Stunt Coordinator

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    I am sure it will be fine. The dealer and adire seem to be very reputable. not worried about it, it is just a pain. especially since I am new to DIY speakers and this is my first project. Thought I had it all figured out. Had my brother come over, got the beers out. turned it on and got nothing but grief from him and my wife. They can dish out quite a razing when someone is down.

    besides, no company wants a mad customer spewing stuff in forums.
     
  15. JakubH

    JakubH Stunt Coordinator

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    [​IMG] I had the same situation. All the people who asked why I'd mailorder a speaker without hearing it piled on their "I told you so". Some in a particularly ignorant mood commented "They probably make this stuff in China" [​IMG] Then of course the one guy who already owns a little Paradigm PDR-10 had to tell me know much better his PDR-10 is, and how I should just get the same instead of wasting my time on 'this mailorder crap'. Just something I'll have to remember for future reference; never tell anyone about your 'DIY purchases/projects until you've tested them in your system, that way you avoid the snarky comments [​IMG]
     
  16. Wayne Ernst

    Wayne Ernst Cinematographer

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    That's why we quietly do some "dry runs" with our new subs in the garage. If there is a driver issue, we just lengthen the build process by a few weeks until the new driver arrives.

    However, Perry, you sub cabinet looks awesome. I'm sure this little wait on the driver replacement will be well worth it. If you are in a pinch for a "bass fix" then you could head for Circuit City and pick up a Profile automotive subwoofer/driver for only $39.00. Then, put the Shiva in when it arrives and use the Profile driver for another sub box in your bedroom.

    Finally, we (those of use who love to build things) will hardly ever settle for "off-the-shelf" speakers and subs. That's what makes us different than the rest.
     
  17. perry web

    perry web Stunt Coordinator

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    I am in no real hurry but I did pull on of the 12yr old pyle drivers out of the speakers in the garage and just layed it in the opening. I did not hook up both voice coils. I was not sure if it was 4or8 ohm coils. did not want to hurt the amp screwing around. This thing is going to be loud. It had good bass even though the speaker was a couple of inches inside box. I have know idea what type of t/s parameters it has. I am sure they are not good.

    I need to do all the finish work on it before I can put it int he living room anyway. I have to pull everything out to do the work and it will take some time.
    next time though I will do my testing more on the sly. Needed my brother to help carry the damn thing into the house. I could have my self but why set down your beer if you do not have to.
    I had to nag the wife for months for approval. I told her our newborn liked bass and needed it so now when the baby starts crying she tells me the baby is crying cuz her speaker does not work.

    thanks for the compliaments on the box. it is easier when you have the right tools. the box sure is strong. I think it would support my truck. I hope I never stub my toe on it.
     
  18. JakubH

    JakubH Stunt Coordinator

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    Hey Perry - just wondering if you ever got your replacement from Adire, how long it took, did they send a new unit or repair the old one? I'm still waiting myself so am just wondering how someone else made out.
     
  19. perry web

    perry web Stunt Coordinator

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    I got mine a couple of weeks ago.
    I sent it back w/ the form filled out. they emailed me w/ in a day or two saying it was diffently a valid warrenty issue and they would send one out to me as soon as they restocked. It would have been much fast except they were out of stock. It took about 2 wks to restock and then a new one was mailed. It arrived early march and works great.

    I thought i was had another bad one but i had wire come off during install so i was only running one vc. once that was put back on it is much stronger now.


    http://www.hometheaterforum.com/htfo...hreadid=184657
     
  20. Rory Buszka

    Rory Buszka Supporting Actor

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    My 10" Blueprint 1001 with the PE 120w amp positively trounced my friend's Sony SA-WM40 (12", 120W) in quality and quantity ("Make my subwoofer sound like that!"). After that, there was never any doubt of my DIY projects.
     

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