Do I really need a subwoofer?

Discussion in 'Archived Threads 2001-2004' started by Dan_J_H., Nov 1, 2002.

  1. Dan_J_H.

    Dan_J_H. Stunt Coordinator

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    My front main pair of speakers are Cerwin Vega VS-150's. These are 3-way speakers with 15" woofers. I get powerful bass with these speakers. Would a subwoofer along with smaller main speakers give me a better sound? My other speakers are: Polk Audio (surround), Boston A. (center).

    Does anyone ever get "two" subwoofers? Or is this overkill.

    Thanks,

    Dan
     
  2. Dustin B

    Dustin B Producer

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    Depends. For home theater action movies a resounding yes. If your musical tastes contain content in the last octave a resounding yes. If you are music only and your tastes don't take you into the last octave then maybe not.
    As for people using two subs. Very common, some use more. Depending on output levels desired, some rooms it would be overkill and others you'd still need more.
    I can't find the picture I wanted to show you. Pic of Tom Vodhanel's room a while before he started SVS. Had a dozen or so sonotube subs all hooked up and wrapped around the corner of his room. But this will have to do I guess:
    [​IMG]
    There are 6 more 12" drivers on the other side :p)
     
  3. Chris Tsutsui

    Chris Tsutsui Screenwriter

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    Remember it's not just cone size that matters but also factors such as how much air it can it move. I guess it depends how deep the Cerwin Vegas can go. I assume that they probably don't have a whole lot of of bass 30hz and below which would mean adding a good subwoofer can make your system more full range.

    The best parts of having a separate subwoofer:

    1. Deep extension and direct signal feed from LFE channel
    2. Position flexibility for best bass response in room
    3. Separate beefier power supply so as not to draw power from the amp that may also be powering the mids/highs. (Bass transients (short notes) can draw a ton of power)
    4. You get a choice on what kind of bass you want whether it's punchy/boomy bass or smooth accurate bass.

    If you go to an audio/video store, demo their subwoofers and listen for a difference that they have over your 2 mains. That's basically what you're missing.

    As for Overkill... I am a firm believer in that there is no such thing as overkill unless you spend too much $. There is a thing called volume control that can turn the volume down on whatever you buy. With 2 subs you get to play with positions and you get some additional volume. (Not that much volume might I add as it usually rangest between 3 and 6 decibels)

    Perhaps overkill might be when you get a sub that with one false move you can cause permanent hearing damage. Like maybe a sub that can output 150 decibels.
     
  4. Mike Poindexter

    Mike Poindexter Stunt Coordinator

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    You won't find a sub that can put out 150 db very easily except the low frequency sonar from a nuclear submarine, which can put out 215db!! and has been responsible for killing whales.
    Run subs, but don't replace your mains with smaller frequency range speakers and expect it to sound better in the bass region. You may get better tweeters and mids on your new speakers, but the bass will go from stereo to mono (the LFE channel) and then come out of both subs so you have dual mono bass.
    Although I don't run any subwoofers, some people would view it as though I have a sub on every channel because the bass comes from a seperate speaker enclosure with a dedicated mono amp for the bass:
    http://www.avsforum.com/photopost/sh...at=500&thumb=1
    Bass on every channel is the goal. If your mains have the oomph they should, you won't need a sub. Until then, pump it up on all channels you can. Bass from a full range center is such a massive improvement over these wanna-be speakers most companies sell as a center that it is amazing that more center speakers are not full range.
     
  5. Dustin B

    Dustin B Producer

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    Damn Mike, that's crazy. I disagree that full range on all 5 channels is the goal though. Well I guess it could be, but getting the room setup right to support that would be difficult. Much easier to get great bass response in room from a single source using a good quality crossover. Also a lot cheaper [​IMG]
    What happens to the LFE signal in your system? Sent to the fronts, all 5 speakers?
     
  6. Mike Poindexter

    Mike Poindexter Stunt Coordinator

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    The LFE is sent to the mains. I don't think that there are any processors that would send the LFE to the rear and center even if you wanted because my set-up is not very common.

    I can switch my system to small rear and center speakers in the processor and you can definitely tell the difference vs. full range.

    I used to think that my laserdisc was great until I went to DVD. I thought my DVD was great until I went to an HTPC for scaled progressive output. Then I got HDTV. Each time, what I used to think was great very soon started to look bad.

    Same thing with the bass. I wouldn't call full range with a single sub great today, but I would have years ago. Full range in 5 channels is as big an upgrade as 5.1 vs. pro-logic.
     
  7. Michael R Price

    Michael R Price Screenwriter

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    Mike,

    Have you tried using a single large subwoofer in a corner with parametric EQ? I can imagine you would have room response problems with 5 sources of bass.
     
  8. Mike Poindexter

    Mike Poindexter Stunt Coordinator

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    A single large subwoofer? Sorry, but there does not exist in the world a portable single large subwoofer that will do what I am doing in bass.
    As for the sources of bass, it is actually 8 sources, as I have 2 pairs of surorunds and also a center surround speaker. The grand total is 32 12" drivers.
    Even if I was to do that, what would I do with my woofers?
    Actually, I could use one woofer tower as my sub, but I cannot easily reposition it. It took 4 people to pick it up and it was a struggle at that. It won't slide on my carpet unless I slip thich carboard under it and even then it takes 2 people to slide it. Still, that puts me in mono bass on the front and I can already tell you that won't do.
    My set-up is a little different now than the pictures here, but this will give you an idea:
    http://www.avsforum.com/photopost/sh...at=500&thumb=1
    And I just went over my frequency response curves with a sound meter. I have more problems in the high end because of the glass on the right side than problems with the bass, which is fairly flat except for one hump where two of the nodes overlap. I will be fixing this and the glass problem by building a room onto the house.
     
  9. Michael R Price

    Michael R Price Screenwriter

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    Oh holy cow, that's crazy. I think you have enough bass. Am I allowed to ask how much that cost?
     
  10. Dustin B

    Dustin B Producer

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    What is the woofer tower crossed over (any specifics on the crossover would be nice too) to the other stuff at?

    Are the woofer towers sealed?

    Also depending on the excursion abilities of those 12" woofers, It could take two to who knows how many of them to equal a single more capable sub driver. And at 8 of them, well then a quad Tempest infinite baffel should be able to keep up.
     
  11. Mike Poindexter

    Mike Poindexter Stunt Coordinator

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    Michael,

    The retail on the whole system (mains, centers and surrounds) was $94,000.

    Dustin,

    The woofer towers are all sealed. I am a firm believer in accoustic suspension over bass reflex. These woofers have some pretty long excusion. I doubt that they have the throw distance of some of the high excursion woofers made today, but there is more to bass than just excursion and high db spl output. These bass towers deliver high output with incredibly low distortion levels. Still, I think that 122.5 db at 15 Hz should be loud enough for anybody.

    An infinite baffle design is great, but it is not exactly portable. Sure, it can shake the house, but they cannot shake as much as my D-Box Odyssee will. What I bought the IRS V for was the best sound I could get. There is no upgrade from these except to buy the newer Arnie Nudell model Genesis 1.1 for 2.25 times as much. The D-Box Odyssee will go as low as you can get, but 7 Hz will still not make you soil yourself.

    Yes, an infinite baffle design will keep up in volume output, but without the servo feedback controls, you are putting out bass with much higher distortion. If I wanted high output with little care for distortion, then I would be into car audio.

    Oh, the woofer crossover is adjustable on both the bottom and top end, plus you are able to adjust the volume output seperate from the main system volume and also the slope of the rolloff curve should you decide that you want to roll off faster for some reason. The phase is also adjustable.

    The schematics of the crossover are a bit complex, but I cannot fit the schematic on my flatbed scanner, as it is a rather large sheet.

    Please don't take this as a bashing of the infinite baffle design, which I think is great and really a hell of a deal in performance/price, nor that I am an audio snob. It is just that subs are more than simply output volume and frequency response curves. Distortion is one of the things I find amazingly high in a lot of subs and not many people seem to address it.
     
  12. Dustin B

    Dustin B Producer

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    Well some people feel just as strongly the other way about servo feedback circuits. So to each his own I guess.

    I would prefer to stay away from them and instead use more capable drivers to keep distortion down. I'm hopeful Adire will release an XBL^2 version of the Tempest by the time I'm ready to build a quad 15" infinite baffel. Then I'll resistively damp it to around a Q of 0.6 take care of any room nulls with some helmholtz resonators or bass traps and tame any peaks with a parametric EQ. The tricky part will be finding the money for a quality processor with good bass management.
     
  13. mark rush

    mark rush Stunt Coordinator

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    I was going to say something but after seeing your speaker setup Mike I think I will shut up! bet your neighbors love you! my neighbors hate me and all I have are 4 klf20's and a klfc7 center and two paradigm pw2200, for a total of 2-12's 8-10's and 2-8's sounds good to me though, I would love to hear your system oneday
    Mark
     
  14. Steve_Ma

    Steve_Ma Second Unit

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    Dan,
    One thing to try is to get a test disk and play some tones through your system. See how much oomph your woofers have below 30hz. It won't address any distortion issues, but for better or worse... It'll tell you exactly what your speakers are capable of as far as SPLs at given frequencies. I suspect that you'd probably benefit from adding a sub, but whether or not you NEED one is a question only you can answer.
    --Steve
     

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