Subwoofer incompatibility problem

Discussion in 'Archived Threads 2001-2004' started by Ryan Cruz, May 29, 2002.

  1. Ryan Cruz

    Ryan Cruz Stunt Coordinator

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    I have just recently bought Mission 705's, which are full range towers. They each have amps which power 4 8" woofers. Because of this, I have no need for my 12" subwoofer. In fact, when I turn the sub with the towers, the bass is weaker, and I suspect that they cancel each other out.

    Is there a way in which I can still use my sub by tweaking crossover freq., phase, or maybe using them for my rear surrounds? I'm not sure whether to sell it or use it.
     
  2. Shawn Solar

    Shawn Solar Supporting Actor

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    If its for music only try lowering the crossover on the sub to lowest marked setting. I am not sure where you have the sub but try it at the front of the room near a corner. Before you turn down the crossover but after you move the sub(if you have to) fiddle with the phase. Turn it until the bass from your mains and sub match. or where the bass sounds the fullest.
     
  3. Ryan Cruz

    Ryan Cruz Stunt Coordinator

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    Yup it is in the corner, while my speakers are in the front. When I turn on the sub the overall bass actually becomes weaker. So you mean to say I can fix this by fiddling with the controls of the sub?
     
  4. JohnRice

    JohnRice Lead Actor

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    It is most likely something that will be helped by adjusting the phase control, if the sub has one. You can sit at the listening position and have someone else adjust the phase until you get maximum bass. If your sub doesn;t have a phase dial, it will be more complex.
     
  5. Chris Tsutsui

    Chris Tsutsui Screenwriter

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    It's phase control that helps adjust the bass. What I tried was adjusting the phase during a constant bass tone. What I noticed was my SPL meter changing radically at some points in the room as I changed the phase from 0-180 degrees.

    I think you're right on how the bass cancels eachother out. When a speaker in phase and a speaker out of phase both play, u get cancelation.
     
  6. John Garcia

    John Garcia Executive Producer

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    Phase is one method, but in this case, I think repositioning the sub will make a bigger difference. What sub and is it front or down firing?
     
  7. Neil Joseph

    Neil Joseph Lead Actor

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    Hmmm, I really like the idea of full range all around so I would (in your situation) try using the 12" sub for the rear surrounds only to capture the full range effects in the back.
     
  8. John Garcia

    John Garcia Executive Producer

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    Even with dual 8" drivers, I still can't see these speakers covering the bottom octave of sound. You did not say what sub, but if it doesn't go any lower in frequency than the mains, then it probably isn't helping. For music, this is probably just fine, but for HT, you may need a better sub for LFE.
     
  9. Johnny Mac

    Johnny Mac Stunt Coordinator

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    I agree with John. What is the low frequency rating for the towers and the sub? Given the bass output of the towers, you would probably just want the sub to take over where they cut out if possible.
     
  10. Shane G

    Shane G Agent

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    I have a similar setup with Paradigm Monitor 70P's and a Paradigm PW2200 subwoofer.
    I used to run my mains as large and have the subwoofer on, but I felt the bass was quite boomey in that configuration.
    Now I have my Denon AVR3300 set up in Direct mode, with the mains set as small (80hz crossover), and the subwoofer on.

    I also have the LFE/subwoofer inputs on the 70P's plugged into the left and right mainspeaker pre-outs. This enables me to adjust the the bass levels on the speakers by using the volume control on the speakers built in subwoofer amps.

    The subwoofer is cornerloaded, and the phase knob adjusted for loudest/tightest bass. I also utilize the subs built in crossover and have it set to about 60hz. This helps to reduce localization of the sub in my setup, because it is right beside the couch. The subs volume control is set quite "hot" at over half.

    This configuration gives very tight/strong/musical bass, and IMO utilizes each component optimally. The speakers give tremendous mid-bass without over straining on the bottom octaves, and the sub takes only the deepest octaves. You might want to experiment with your setup.
    Hope this helps.
     
  11. Darrin_R

    Darrin_R Stunt Coordinator

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    Shane G

    When you put the Denon in direct mode it bypasses the large/small speaker setting. Frequencies below 80hz are not being filtered from the mains.
     
  12. Shane G

    Shane G Agent

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    Darrin R.

    I know the direct mode bypasses all the tone controls etc. but I'm not sure (with out having my owners manual and stereo in front of me to confirm) that the direct mode bypasses the bass management section. You may be right...
    I'll have to wait untill I get home from work to check it out. If that is the case however, would not the subwoofer outlet be disabled? The reciever has to be doing some form of bass management if the subwoofer outlet is active, does it not?

    Do you have the AVR3300 or other Denon receiver and confirmed that bass managemnent does not occur in Direct mode. Its been a while since I've played with my settings on my reciever. But here's a quote from a review on the 3300;
    "A parallel bass management circuit provides high pass/low pass filtering for the main left and right speakers and the subwoofer...."
    I know this deviates from the original post, sorry..
     
  13. EarleD

    EarleD Supporting Actor

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    Shane,

    Im pretty sure that if you are using a digital connection with the Direct setting, you are still using the bass management of the receiver(speaker settings, ETC)

    If you go with a analog connect you bypass the receivers bass management and the mains are now run as large.

    The subout is active in both modes, and output is xover at 80hz.
     
  14. Ryan Cruz

    Ryan Cruz Stunt Coordinator

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    From the Mission website:

    The Mission 705A is an active loudspeaker with an exceptionally dynamic power delivery.

    Two specially selected 200 mm bass units are driven by an integral power amplifier, fully level adjustable for individual preference. As each 705A has its own dedicated amplifier, separation is outstanding with no crosstalk or power drain and the whole ensemble provides effortlessly deep floor-shaking bass without strain or fatigue. An active bass crossover minimises insertion losses.

    For music or home theatre reproduction of the highest standard, the 705A is a prodigious performer.


    705A
    3-way, reflex-loaded tower

    Frequency response ±3dB
    30Hz to 20kHz

    Sensitivity: 89dB


    100W on-board Bass amplifier

    Finish: Black Ash

    Does it sound as if it can handle all my bass?
     
  15. Neil Joseph

    Neil Joseph Lead Actor

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    You would be missing some of the bottom end and for a lot of the newer movies, they have info below 25Hz and below 20Hz in some cases.
     
  16. Darrin_R

    Darrin_R Stunt Coordinator

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    Shane G

    Yes, I have the 2801. I am positive that the 2801/3801 does not filter anything from the mains when in direct mode. But Ryan Cruz made a good point. When I tested this I was using an analog connection. So I didnt test it with the digital connection which I am now using. But I will.

    Sorry for the stray post.
     
  17. Shane G

    Shane G Agent

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    EarleD,Darrin-R & Ryan

    I also have the setting for the subwoofer set to "subwoofer only" as opposed to "subwoofer & mains", the manual says that experimenting with these settings will have an effect on bass cancellations between the sub and mains.

    Ryan,
    What are your bass management settings at?
    How do you have your mainspeakers hooked up?
    What is your subwoofer, and its specifications?
    Your Missions may very well have better bass reproducing capabilities than your sub.

    Darrin-R,
    I use my digital connection, and I think you may be right, that the mains might stay as large. But, I think the "subwoofer only" setting still works, and that along with subwoofer placement (primarily the subs placement) help played a factor in reducing the boominess). I played around a little with the settings last night, and the owners manual mentions absolutely nothing about bypassing the small/large settings.
     
  18. Ryan Cruz

    Ryan Cruz Stunt Coordinator

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    My mainspeakers are tri-wired (bi-wired to one channel each plus a subwoofer out on each tower). I have them set as small, and the sub is set to normal on my Denon 2802 receiver.

    My subwoofer is just a DIY given to me capable of 30hz. Tweaking with the phase settings, i was able to make it work with the towers, although offering a little improvement in sound. What would happen if I use the sub for the rears, would it be of good use there?
     
  19. Shane G

    Shane G Agent

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    Ryan;

    You have your speakers set up almost identical to mine, except you have the bass section set up via the subwoofer outputs. I have mine hooked up to the left/right speaker out-puts, and the only the subwoofer hooked up to the sub-out.

    You must have a couple y-splitters dividing up the sub-out eh?

    Have you tried hooking the speakers bass section up the L/R speaker outs as an experiment? That way you could use the receiver to increase the sub level, and your sub should be running on a different frequency, helping to eliminate your bass cancellations, that you think you are having. This set up will also allow your mains to run in stereo bass, and you can then increase the volume on your speakers amps to fill out the bass to your liking.

    You could use your sub for the rears, but you'll likely need some sort of subwoofer x-over network, if your sub doesn't have one built in. You'd then have to run your fronts as large, in order for the rears to be large.

    Your next upgrade will probably be a subwoofer than has good output in the 20hz range. If you really want the type of bass than feels like it lifts your couch up and down, and bounces the pictures on the walls.
     
  20. Ryan Cruz

    Ryan Cruz Stunt Coordinator

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    OK I'll try hooking up my front towers via the L/R speaker outs. I'm wondering how that's going to turn out. If I do that, will I still set my towers as
    small?
     

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