SVS questions..Why can't I turn it up? Speaker seems very fragile. 20-39 PC+

Discussion in 'Speakers & Subwoofers' started by Brian.Huep, Oct 28, 2003.

  1. Brian.Huep

    Brian.Huep Agent

    Joined:
    Jul 25, 2003
    Messages:
    43
    Likes Received:
    0
    Trophy Points:
    0
    Hello guys,

    I recently purchased a 20-39pc+ for my HT. I have it hooked up to a Harman Kardon avr55 which is 55watt per channel.

    It is in a fairly large area, which I have tried to close in as much as possible.

    My problem with it is the volume. If I turn the sub up past 40% volume, with the receiver on 0 boost, once in a while a movie will make it bottom out. Or over exert, whatever you want to call it. It sounds bad.

    I try to find a happy medium with the volume, but some movies hit hard and will bottom it out. I hate adjusting it per movie.

    The sub just sounds so weak unless I can turn it up past 40% volume.

    I do have it in a corner, and I did calibrate it. But who really uses calibrated level on thier sub!


    How high do you guys have your SVS turned up?

    I see people hitting 115 db on a 20-39pc, I get nervous at 95-100db's of it bottoming out. Why are the drivers so weak?

    I had an old JBL 12inch sub before this that I could run at 100% power and never heard a "bottoming" out noise.

    I also can crank my mains/center to the receiver max and never hear anything bad. Klipsch quartet mains, academy center.

    I am very confused, I feel like I am constantly babying this SVS, it feels fragile.

    Thanks
     
  2. Geno

    Geno Supporting Actor

    Joined:
    Oct 1, 2001
    Messages:
    637
    Likes Received:
    0
    Trophy Points:
    0
    where are you turning up the volume for your sub? on the sub's amp? or the HK?
    where is the gain on your sub's amp?
     
  3. terence

    terence Supporting Actor

    Joined:
    Nov 8, 2002
    Messages:
    985
    Likes Received:
    0
    Trophy Points:
    0
     
  4. Brian.Huep

    Brian.Huep Agent

    Joined:
    Jul 25, 2003
    Messages:
    43
    Likes Received:
    0
    Trophy Points:
    0
    I am turning the volume knob on the sub. I left the receiver at 0 for the sub. The sub's volume knob is at 40% at the most.

    The room is 24x35 or so, I have a 11x15 area blocked off, but only with a thick velvet curtain. At 40% volume I have trouble understanding why the sub will bottom out.

    One thing I wonder about, is how come the 20-39pc+ has a 525 watt amp in it if it can't be turned up. The 20-39pc has a 325 or so watt amp, it seems like even turning that up would blow it. Why put a larger amp in the sub if the driver cannot handle the load??

    Thanks guys,

    Brian
     
  5. Geno

    Geno Supporting Actor

    Joined:
    Oct 1, 2001
    Messages:
    637
    Likes Received:
    0
    Trophy Points:
    0
    Ok there is your problem. the sub volume/gain should be set and not touched. you say you have calibrated but everytime you change the sub volume on the sub amp, you are meesing with the calibration.

    Look at it this way, when you turn up the volume on the HK, it will increase the power going to your sub, then your sub will amplify that signal to whatever the gain on the BASH amp is set to.

    I dont think Im being clear enough but im sure someone will chime in and hopefully explain better than I do.

    All I can say is, set the SVS at about 1/3 then calibrate then never touch the amp volume again.
     
  6. Rob Grim

    Rob Grim Stunt Coordinator

    Joined:
    Aug 5, 2003
    Messages:
    88
    Likes Received:
    0
    Trophy Points:
    0
    First thing is first, how do you have your SVS setup, plugs, SS filter, etc. Second off, from the way I'm reading this, I could be wrong, but it sounds like you are a major bass head. Subs are designed to pick up where your mains just won't cut it, meaning, your sub should almost sound invisible. Let us in on a little more info, eqipement, settings, etc.
     
  7. Brian.Huep

    Brian.Huep Agent

    Joined:
    Jul 25, 2003
    Messages:
    43
    Likes Received:
    0
    Trophy Points:
    0
    I know exactly what you mean, and yes once I set the sub volume I will adjust it on the receiver for certain movies. That said though, with the receiver boost on zero, shouldn't I be able to turn the svs up to say 75% power? Why can't it take even 1/2 of the power of the built in amp it came with? Why even bother putting a 525 watt in them, if the 325 watt could still blow it?

    I am just pissed that I have to baby the darn thing, I purchased a nice one, but am afraid to even turn it up. The calibrated level is so low it plays quiter then my old 12inch jbl junk sub. But if I turn it up, it will bottom out sometimes.

    /shrug....

    Thanks again for your info.
    Brian
     
  8. Brian.Huep

    Brian.Huep Agent

    Joined:
    Jul 25, 2003
    Messages:
    43
    Likes Received:
    0
    Trophy Points:
    0
    Correct Rob, I like my bass. My mains put out some pretty serious bass, so the svs really has to be turned up to match. I use Klipsch Quartet mains, the ones with a 12 inch passive radiator in the back, and a 10 in the front along with 2 horns. They can thump pretty well. The academy center is no slouch either.

    I like feeling bass, but I don't feel I am turning it up past where I should be able to.

    I have the svs setup using no port plugs, and set at 16hz, so it goes just a tad deeper. Not like I can really tell, it's hard to hear the sub.

    I am so lost on this.
    Had plenty of subs in the past, and never had to worry about bottoming out.
     
  9. Sheldon C

    Sheldon C Second Unit

    Joined:
    Dec 27, 2001
    Messages:
    379
    Likes Received:
    0
    Trophy Points:
    0
    Something is wrong. You should not be anywhere near the subs limit at 95 to 100 db. My 20-39 pci can hit 108 db in a fairly large room. I would think that you should hit around the same db as me since your room is bigger BUT you have the plus sub.
     
  10. Geno

    Geno Supporting Actor

    Joined:
    Oct 1, 2001
    Messages:
    637
    Likes Received:
    0
    Trophy Points:
    0
    Brian, I see your point.

    All I can say now is try to email SVS, or PM one of them here at HTF. From what I have read, their customer service is excellent, so you should get to the bottom of this real soon.


    PS - many DIY'ers have the same situation you have, try doing searches in the DIY for this problem, and im sure there will be much to read
     
  11. Geno

    Geno Supporting Actor

    Joined:
    Oct 1, 2001
    Messages:
    637
    Likes Received:
    0
    Trophy Points:
    0
    Hey Sheldon, good to see another Johnson County'er here at HTF.

    Sheldon, where is your sub amp set up at?
     
  12. Rob Grim

    Rob Grim Stunt Coordinator

    Joined:
    Aug 5, 2003
    Messages:
    88
    Likes Received:
    0
    Trophy Points:
    0
    Have you tried plugging a port or two. I beleive if you plug a port or two it will dig much deeper but you will lose some SPL. The combination of the SS filter and being able to plug the ports is what prevents it from bottoming out. Give that a shot. Also, what is the subwoofer setting/volume on your receiver set at. Anything in the positive is not recommended.
     
  13. Geno

    Geno Supporting Actor

    Joined:
    Oct 1, 2001
    Messages:
    637
    Likes Received:
    0
    Trophy Points:
    0
  14. Tom Vodhanel

    Tom Vodhanel Cinematographer

    Joined:
    Sep 4, 1998
    Messages:
    2,215
    Likes Received:
    8
    Trophy Points:
    0
    Hi Brian,

    In approximately 7000 cu-ft, a single PC+ isn't going to handle anything close to reference levels on today's action oriented DVDs. We might be able to optimize your subwoofer a little better though.

    1) Please read the instruction manual. You should NOT set the amp to 16hz unless you use one port plug to change the tuning point of the enclosure to 16hz.

    The purpose of the subsonic filter is to ATTENUATE the signal strength below the tuning point of the enclosure. So when you have all 3 ports open (20hz tuning) you should only use the 20hz setting on the amplifier. When you have all three ports open, and use the 16hz setting on the amp...not only aren't you attenuating the signal...you are actually BOOSTING it. This is very abusive to the subwoofer driver and will often lead to premature failures.

    So for now, don't use any port plugs and set the amp to 20hz mode.

    2)If you haven't already, try placing the subwoofer in the corner closest to the key seating positions. This should maximize the system *sensitivity* of the subwoofer...giving you more output for a given amount of input power to the driver.

    3)be sure to calibrate the whole system with a SPL meter. Set all speakers to the same levels, and once finished, don't adjust anything separately (like the subwoofer volume knob).

    Let me know if this helps at all Brian,

    Tom V.
    SVS
     
  15. Brian.Huep

    Brian.Huep Agent

    Joined:
    Jul 25, 2003
    Messages:
    43
    Likes Received:
    0
    Trophy Points:
    0
    Ok Tom, I set it to 20hz, and no ports plugged. The sub is in a corner close to the listening position. I have calibrated every speaker.

    I understand I won't get reference levels with 1 svs. Not too worried about that at all.

    What bothers me is, what is the use of a 525 watt amp, if the sub can't be turned up more then 40% without bottoming out? Seems like the standard 20-39pc with the 325 watt amp would be plenty. Why the extra power, if it bottoms out?

    I am afraid of blowing the sub. In some movies like 2 fast 2 furious, you want the extra bass to feel like your there with the thumping cars, etc.. yet I am afraid to turn it up.

    Thanks for your advice,

    Brian
     
  16. Joe Wilmore

    Joe Wilmore Stunt Coordinator

    Joined:
    Jan 8, 2002
    Messages:
    130
    Likes Received:
    0
    Trophy Points:
    0
    If you receiver is at 0, there is no way you should have the amp at 40%. Try lowering your receiver to -5. You are probably running it about 15 db's hot.
     
  17. Brian.Huep

    Brian.Huep Agent

    Joined:
    Jul 25, 2003
    Messages:
    43
    Likes Received:
    0
    Trophy Points:
    0
    But that's my question Joe, why can't I have the sub at 40% with my receiver at 0?

    Why make the sub's volume control go to 10 if once you go past 4 it bottoms out??

    Why make a 525 watt version if the 325 version will still bottom out?

    What am I not grasping here?

    Thanks
    Brian
     
  18. Sheldon C

    Sheldon C Second Unit

    Joined:
    Dec 27, 2001
    Messages:
    379
    Likes Received:
    0
    Trophy Points:
    0
    Geno,

    Lenexa huh, cool. I now live in Shawnee. You're the first JOCO guy I've noticed. I keep my svs set at a little over 1/3 of the way up. I am thinking about getting another so I can get pretty close to 115db peaks as soon as I upgrade my center and surrounds to match my new mains (Axiom m60's).
     
  19. Rob Grim

    Rob Grim Stunt Coordinator

    Joined:
    Aug 5, 2003
    Messages:
    88
    Likes Received:
    0
    Trophy Points:
    0
    Okay Brian, next question. What are all your speakers set at.
     
  20. Edward J M

    Edward J M Cinematographer

    Joined:
    Sep 22, 2002
    Messages:
    2,031
    Likes Received:
    0
    Trophy Points:
    0
    Brian:

    The amount of power being fed to the driver has almost no relation to the "percent setting" on the amp's volume control.

    The amount of power being fed to the driver is affected by three things:

    1) The Master Volume setting on your AVR.

    2) The relative strength of the subwoofer pre-out signal. Some pre-outs are considerably weaker/stronger than others, when measured in millivolts, at any given arbitrary setting (say -5).

    3) The volume setting of the subwoofer plate amp.

    It is not only possible but very easy for the SVS BASH plate amp to deliver its full rated power (and then some) into the driver's voice coil at what you refer to as a "40% setting". If you feed the amp input a strong enough signal, it will drive the amp to full power, even if you set the volume control to "20%".

    In that size room, DEFINITELY run the sub in the 3/20 tune. As Tom states, running 3/16 will bottom the driver for sure at extreme levels and is not recommended. The 3/20 tune is the safest and the loudest and the sub will troll to 17 Hz in that tune anyway so extension is not an issue. Place it as close to the key listening spots as possible, preferably corner loaded.

    If that is still not satisfactory, you are a good candidate for dual 25-31 PC+ or a PB2+ which offer maximum output in the 22 Hz and above region in a room that size.

    Regards,

    Ed
     

Share This Page