SVS 20-39PC-Plus

Discussion in 'Speakers & Subwoofers' started by Parker Bailey, Jan 2, 2004.

  1. Parker Bailey

    Parker Bailey Auditioning

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    I am almost sure I will be ordering the 20-39 in the next week or so, but I still need your opinions. I now have a definitive technology HT. It consists of BP2000TLs(mains), C/L/R 3000(center), and BP2006TLs(rears). I currently have the 2000s wired w/LFE, and it isn't that bad. Although the bass is a little muddy and tends to distort at very loud volumes. Will it be a big difference if I go with my instincts and get the 20-39PC+?
     
  2. Edward J M

    Edward J M Cinematographer

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    Well, you are already packing two 15" woofers and 1,000 watts from the BP2000TLs, and two 8" woofers and 500 watts from the BP2006TLs, and one 10" woofer and 150 watts from the C/L/R 3000.

    The "problem" with self-powered "full range" speakers is that you feel compelled to run them all on large (full range), regardless of whether they can actually do justice to all the bass in that channel.

    That is why I am not a fan of powered speakers. Despite marketing claims to the contrary, the bass from "most" powered speakers is of lesser quality than what can be obtained from a separate high grade external subwoofer (or two).

    Regardless, I assume you are in no position to replace all of your powered speakers with passive ones, and it would be a waste to run them on small, so I imagine your plans for the 20-39PC+ would be for the LFE channel only? I suppose that would take a considerable load off the BP2000TL's in "most" instances.

    But be aware that the distribution of bass varies greatly both within a DVD and between DVDs. Some DVDs make heavy and consistent use of the LFE channel, and others don't. And some DVDs have full power, full range bass in all channels. So the benefit of directing just the LFE channel to the SVS will not always be realized, depending on the DVD.

    I think you will find the bass quality from the SVS to be excellent, I'm just not sure how well you can integrate it into your existing system to make the most/best use of it. Managing so many sources of low bass in a single room can be tricky, with standing waves and nulls a definite possibility, and they may only occur under certain conditions, which makes them even harder to deal with. Good luck!

    Regards,

    Ed
     
  3. ChrisWiggles

    ChrisWiggles Producer

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    I would go for the + if I were you. It isn't that much more, really.
     
  4. Ralph B

    Ralph B Supporting Actor

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    I was gonna purchase the 25-31 PCI but then decided on the 25-31PC+ . the better driver,more power when I move someday,and to be able to tune it pushed me to the plus.

    I went back and forth too but always questioned myself about the plus and if I didnt buy it. plus I like to be able to play once in a while when I ant and the tuning will make that happen. [​IMG]

    go for the plus. someone said that the first $600 hurts. that is true. for $200 more im getting alot in return.

    I just purchased it 1am this morning. couldnt resist!
     
  5. Robert_Gaither

    Robert_Gaither Screenwriter

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    The single greatest advantage of a standalone sub vs towers is simply placement which, when it comes to bass, sometimes makes all the difference in the world.
     
  6. Parker Bailey

    Parker Bailey Auditioning

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    Edward, actually the 20-39+ would not be just an LFE sub. If I get it I plan to hook it up as my main bass with the 2000's subs turned off or way down. I was asking would it be much of a difference with the SVS hooked up this way?
     
  7. Edward J M

    Edward J M Cinematographer

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    That I couldn't say - never heard them. You have a lot of bass drivers and wattage going for you with the DT's. How well all of them will perform against a single SVS Plus? Hard to say - if you aren't happy with the results, you can always return it after up to a 45 day evaluation.

    I would definitely leave the amps/speakers running, though. Just set them to small (if you are going to go that route) and calibrate them as you would any other speaker.
     
  8. Parker Bailey

    Parker Bailey Auditioning

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    I have never seen how setting the speakers to small would effect the performance. These speakers are HUGE. Would I have to do this if I got a seperate sub for best performance?
     
  9. Edward J M

    Edward J M Cinematographer

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    If you set them all to large and the sub to yes/on, you will send a full range signal to all the surround speakers, and the LFE channel to the subwoofer. This is what I initially presumed you were going to do.

    As I stated above, the distribution of bass varies greatly both within a DVD and between DVDs. Some DVDs make heavy and consistent use of the LFE channel, and others don't. And some DVDs have full power, full range bass in all channels, and some don't. So the expectation of better bass all of the time on every DVD will not always be realized, if you are sending only the LFE channel to the SVS.

    I would say experiment both ways and see what you like the best. Again, you've got a month and a half to find out - that's a very liberal return policy.
     
  10. Parker Bailey

    Parker Bailey Auditioning

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    To get the best bass possible from the 20-39+, do I have to hook them up to my mains. And what is the best way to hook them up? If I don't connect it to my mains would this be considered just an LFE sub?
     
  11. ChrisWiggles

    ChrisWiggles Producer

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    How you hook up the sub, and how you set your receiver determines where the bass goes, and thus what bass the sub gets.

    For almost all setups, setting all your speakers to *SMALL*, you subwoofer to *ON*, will get you the best results. Thus is because there are VERY few speakers out there that can output the bass (both quality and quantity) of an SVS. Also, placement is more flexible with a subwoofer, as where your mains are may be really bad spots for subwoofers.

    To get an LFE only sub, you would set everything large, sub to on, which is essentially no bass management at all. Everything stays going to its respective channel. This poses a lot more strain on your receiver, and unless you TRULY have 5 full-range mains, and PLENTY of power for them, then bass management features rerouting the bass from those channels to the sub is usually the best option.

    There ARE people with CRAZY speakers, and i DO mean crazy. I.E. their mains have their own subwoofer ARRAY, or the mains are literally a HUGE room-filling contraption with arrays of woofers behing them. In THOSE kinds of cases, then certainly bass management may not be needed, or , on the converse, a subwoofer may not be needed at all.

    So you have to ask yourself this question: Do you need a subwoofer at all? If your mains were truly as capable as an SVS, then you may not need a sub at all. I am almost certain that this is NOT the case.
     
  12. Edward J M

    Edward J M Cinematographer

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    It also occured to me this morning you probably have one more option in your BM arsenal.

    You can set your speaks to large, and your sub to LFE + Mains.

    That will send your speakers a full range signal, but not the LFE channel. And it will send the SVS the same signal it would otherwise get when all the speakers were set to small.

    Normally this would result in a bass heavy arrangement, so you could ramp down the amps in your DTs so the woofs stay clean and uncompressed.

    And you can then be sure the SVS will be getting all the bass on the DVD, whether derived from low-passed on the surround channels, or from the LFE channel.

    Overall system calibration will prevent you from being too bass heavy, and your DTs should clean up well relieved of the LFE channel and also running at a reduced level.
     
  13. terence

    terence Supporting Actor

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    Wow Ed, that is how i run my BM for my system. Parker I have two 175W driven 10" drivers in each of my mains (Acoustic Research Hi-Res AR5's) I run them set to large and send all the LFE to the twin 20-39PC+'s. My CC and S, and SB's are set to small, I found this to be the best solution for my HT.



    I also found this too be true, I had to back off on the amp gain on the mains. I have the cut off for the LFE at 70hz, the mains take care of all the upper bass frequecies with authority. The twins handle everything else, now the 70hz is not brick wall the mains will go lower than 70hz but not much.
     
  14. Stephen M

    Stephen M Stunt Coordinator

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    Since you have five full range speakers, if you can, I suggest you set them to small with a xover at 50hz. This setting will allow you to use the sub in the range it is best and make the sub even less locatable by sound due to the low frequency xover. This option would allow you to enjoy almost full range sound from your Def Techs and have the great SVS to hold up the bottom octave. It would also most likely remove any distortion you have heard in the past with the DTs alone.
     
  15. Edward J M

    Edward J M Cinematographer

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    Setting to small at anything less than 80 Hz will lop off the top of the LFE channel, since it can't be redirected anywhere except the subwoofer when the speaks are set to small.

    If he has a separate xo control for the LFE channel alone, he could leave it at 80 Hz, and set the xo for all the surround channels to 50 Hz, I suppose. There aren't many pre/pro's with this capability, though.

    And he also loses the benefit you cited about reduced localization since he still has to leave the LFE channel at 80 Hz (or risk losing content). This is a trade-off at least one HTF member has made though - he uses small and 60 Hz for all channels, including the LFE channel and it seems to work good for him. Personally, I use 80 Hz and it works fine for both music and HT - YMMV.
     
  16. ChrisWiggles

    ChrisWiggles Producer

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    The LFE goes to 120, not 80 as you seem to indicate. From my understanding, setting a low crossover point (lower than 120) for the mains, would not affect the LFE. Though I am not sure.
     
  17. Edward J M

    Edward J M Cinematographer

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    In theory the LFE channel goes to 120 for DD. In practice, it has very little content above 80 Hz.

    The LFE channel and the surround bass are always summed and low passed to the subwoofer at the same frequency when the speakers are set to small.

    The only exception would be if your BM circuit can set the xo for the LFE separately and independently from the xo for the surround channels.

    Since the LFE channel is low passed only, any source content in that channel above your selected xo frequency will be filtered out (probably at 24 dB/octave).
     

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