Bass Mgt. and Large speakers pondered

Discussion in 'Archived Threads 2001-2004' started by Luke_Y, Sep 6, 2001.

  1. Luke_Y

    Luke_Y Second Unit

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    OK, I was reading some posts where bass Mgmt. was being discussed and people were asking what settings to choose if they had "large" floorstanding speakers for the front R/L. The general consensus appeared to be to still set bass Mgmt. to "small" and let a quality sub do the work in the lower range.
    My question is this. If a person were buying new speakers and listened to about 50/50 music/movies what would he gain if he bought Floorstanding towers for the front R/L vs. a smaller speaker? Say Paradigm Monitor 11 vs. Monitor 5 just as an example. If you were using either pair with an excellent sub and setting bass Mgmt. to small why bother spending the extra on the 11's?
    I know you will show me the error in my thought process that's why I'm asking [​IMG]
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    Luke
    [Edited last by Luke_Y on September 06, 2001 at 06:33 PM]
     
  2. Luke_Y

    Luke_Y Second Unit

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    Bump- man this forum moves fast. [​IMG] Bumped down off the first page in a few hours.
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    Luke
     
  3. Darren K Price

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    I woud set them all to small and let the sub handle all of the low frequency work...if you have a decent powered sub. Therefore, using that logic, save your money and buy the mini monitors instead of the big floor standers.
    Darren
     
  4. PatrickM

    PatrickM Screenwriter

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    Luke,
    My tendancy has always been to go with as full range a speaker as you can afford. This doesn't mean you scrimp on the sub though. Get a good sub as well.
    I'm not as keen as others to apply bass management on everything. I want the sub to reproduce the LFE channel but if you have good full range speakers throughout, let them do their job. In my experience bass is more directional than most people lead you to believe so if the bass is in the rear surrounds for example, I want to hear it come from there.
    In the ultimate system I would have all speakers as full range as possible, set them all to large and have one sub for the LFE, one sub wired either to the center pre-outs or the speaker level outputs in parallel so you have a sub dedicated to you center which is almost always limited low frequency and the same for the pair of surrounds so you would have three subs in your system.
    Just my thoughts,
    Patrick
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    If you live in Vancouver, B.C. or the surrounding areas, take a look at the Local Home Theater Forum Meets section for a Vancouver meet.
    My DVD Collection
     
  5. John Garcia

    John Garcia Executive Producer

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  6. Kevin C Brown

    Kevin C Brown Producer

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    I have full range mains, but cross them over at 80 Hz to a "quality" sub.
    You have to be careful, because the crossover is usually recommended to be a full octave above the lower reach of the main speakers.
    In other words, let's say you have mains that are *known good* down to 30 Hz. And what I mean by *known good*, is not just propaganda from the manufacturer, but they have been tested by Stereophile, Sound & Vision, or someone who has graphed the freq response curve *correctly*. (Tom Nousaine, D.B. Keele, David Ranada, etc.!)
    So they are good to 30 Hz, but that means that if you set them to small and cross them over to a sub, the sub crossover needs to be set at 60 Hz. (You double going up for how wide an "octave" is.)
    So, if you did spend less money on the mains, that means the low freq extension will be less, which means you have to continue raising the crossover to the sub. If you get to a crossover too high (above 80 Hz, depending on slope, in my opinion), bam, then those "mid" frequencies become localizable to the sub and you get "crap for sound."
    So, there is a reason why you'd still go with "full range" mains and still cross them over after setting them to small.
    In my case, I have Def Tech BP-30's, which the manufacturer claims to get to 20 Hz, but the output is massively rolled off at that pt. So I figure flat (+/- 3 dB) to 40 Hz, and I double it to get 80 Hz. (I could probably do 60 Hz, but I just use 80 Hz because it works with my centers and surrounds too.)
    Now ultimately, "small" and crossed over, vs "large", you have to listen both ways and decide for yourself. And some people (I don't know why!), run "large" *and* feed their sub with low freq content. Redundant in my opinion. And you can get nasty phase effects bewteen the sub and mains such that you get "nodes" in your room with deconstructive (zero) and constructive (very boomy bass) interference. (Same reason that in most cases, if you have 2 subs, you should stack them together in a corner together, so the ouput is additive, vs spreading them out where they can "fight" each other.)
    Fun stuff!
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  7. DaveGB

    DaveGB Auditioning

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    Luke -
    I am not very knowledgeable compared to the other members but I have a set of full range tower speakers [MB Quart QLC 604]paired with an SVS 20-39. After reading all of the large/small posts and debates, I simply did a blind test and found that I prefer the fronts set to large. This is particularly true for music. The towers just flat out sound better to me on music and since I don't have the luxury of having one dedicated HT system and a separate music setup, I have left them on large. I believe the towers give a better midrange and provide musical bass better than either my current SVS or my previous sub. My .02 anyway.
     
  8. Martice

    Martice Screenwriter

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    As stated earlier, if you like the way your large speakers sound set to small then by all means. However, I've tried that route and I didn't like it as much as when set to large. Some people will say that you should run your large speakers set to small so that you don't over work your receiver as well. Well my response to that is and always will be that if you have quality amplification in the first place you wouldn't need a sub to rescue your amp from over work. Secondly, setting up your system properly, positioning your speakers inorder to get the best sound from them, how your room sounds and is tuned and being realistic about the capabilities of your system will go a long way in helping you experience quality audio/video for years too come.
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    What if it gets no better than this!?!
     
  9. Chris PC

    Chris PC Producer

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    Ideally, the best thing would be to place the subwoofer not far from the main speakers. That would eliminate problems with running the fronts as large and the subwoofer also.
    I think the idea with running FRONT=LARGE and SUB=YES, is that you then crossover the subwoofer at 40-60 hz. You will have overlap, but like many say, it sounds good that way. There is no replacement for proper bass management. Ideally, if you had a crossover frequency you could adjust properly, like I keep saying like a broken record, then it would give you to use your mains fairly low and blend well.
    For instance, If I was to use speakers that go down to 32 hz, I could safely use a 65hz xover or if they only went down to 35 hz, then a 70 hz crossover would probably fit best, etc, etc. I like to play my fronts without a subwoofer sometimes, so I cannot use smaller bookshelfs. Perhaps I move into a space i cannot use a subwoofer for a short time, I don't want to be stuck with limited range bookshelf speakers.
    I will continue to experiment with my setup. So far, I DO NOT like the SMALL front speaker setting. i can definitely localize the sub. Oh well. Its my own fault, as i went ahead to buy a receiver with a 100 hz crossover. Its all I can afford. I'll go with FRONT=LARGE to get around it, or get an external amp and crossover to get real bass management.
    My question is though, when I set my FRONT=LARGE and SUB=YES, what signal is the subwoofer receiving? Because, I want to cross it over at 50-80 hz, probably like 60hz. If its already crossed over at 100hz, I'm cascading crossovers and thats not good. From 60-100 hz I'll have too much of a drop off. Not sure about that. I guess its time to seriously invest in an SPL meter.
    [Edited last by Chris PC on September 07, 2001 at 06:14 PM]
     
  10. Nick G

    Nick G Stunt Coordinator

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    Chris, perhaps I am missing something, but I don't see your problem. If, for example, your main speakers go down to 50Hz, then you set them as "large", sub as "yes" and then set the crossover on your sub at 50Hz. You may need to experiment with the 50Hz crossover setting and volume on the sub a bit to get everything dialed in just right, but that is always the case.
    Regards, Nick
     
  11. Kevin C Brown

    Kevin C Brown Producer

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    Usually you use the crossover setting in your pre-pro/receiver, and leave the sub full range.
    If you enable both cross-overs, which is cascading, probably isn't a good thing. Just let the receiver do the decision making between the mains and the sub.
    I think, the only time you'd use the crossover in the sub, is if you run speaker level connections for L + R to the sub, then use the crossover there to split between low freq at the sub, then send the high freq *from* the sub *to* your main speakers with again speaker level connections. This is how the Vandersteen 2WQ and some other subs are set up.
    Also, if your mains only go to 50 Hz, you have to crossover at 100 Hz anyway, or else you risk overdriver the mains.
    Remember, a crossover freq is the *starting* pt for where the sound slopes off. It's not a brick wall filter.
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  12. Chris PC

    Chris PC Producer

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    The speakers I am using right now go down to about 45 hz - 3 db point. Setting the subwoofer xover at 50 to 60 hz with the FRONT=LARGE seems ok. There must be some overlap there though, enev with the subwoofer set to 50 hz. from 40-60hz, there would be a peak for sure.
    The problem is, I am buying speakers with a low frequency -3 dB point of either 35 or 32 hz. If I run the FRONT=LARGE and crossover the subwoofer at 50hz, then I have an even bigger overlap. Now its from roughly 30-55 or 60 hz. I am buying front speakers with good low frequency response for 2 reasons:
    1) I want to listen without my subwoofer sometimes
    2) The lower the response, the more flexibility I have with crossover settings, ie a 32hz -3dB means I could use a 65hz crossover, rather than with a bookshelf having a - 3dB of 49hz, which would require a 100 hz crossover.
    If the bass overlaps, it won;t just make a peak, the subwoofer is over in the corner and the full range front speakers are in 2 other locations. So for the overlapping frequencies, you will have cancelations "valleys" as well as "peaks" in the response.
    Regardless, I have heard many say that, despite that others argue its not right, they like setting their FRONT=LARGE and SUB=YES.
    I'll keep experiementing and listening. I really need an SPL meter.
    Ideally, I'd get an external crossover, set FRONT=LARGE and SUB=NO and connect the xover to the front left and right preouts, connect the xover to the subwoofer and the xover high pass output to an external amp to drive the fronts. Ideally a crossover like the Mirage LFX-1 has a 50-100hz filter for the subwoofer and a 50-100hz xover for the high range speakers.
    There is disagreement over whether you can get good sound by overlapping via FRONT=LARGE and SUB=NO. Some say you need to use FRONT=SMALL and SUB=YES.
    [Edited last by Chris PC on September 07, 2001 at 08:45 PM]
    [Edited last by Chris PC on September 07, 2001 at 08:48 PM]
     
  13. Drew Eckhardt

    Drew Eckhardt Stunt Coordinator

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    There are two ways to get acceptable well integrated full-range performance and perhaps a third:
    1. Sealed or ported mains which will play flat a full octave below (half the frequency of) a cross-over at no more than 80Hz (Currently, I like this best and use it personally although I think it may be more a function of the speakers I've heard in reasonable environments than inherent superiority).
    2. Sealed mains which yield a 12dB/octave natural roll-off, a 12dB/octave high-pass at the same frequency which is
     
  14. Kevin C Brown

    Kevin C Brown Producer

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    Chris- OK, you are thinking about it right! [​IMG]
    3 more thangs to think about:
    1) I suspect that the reason why people say that running their mains Large *with* a crossover set to their subs, is simply because it sounds louder due to that overlap.
    (Something "louder" will always be perceived as "better" sounding. Psycho-acoustical theory or somesuch!)
    I think that thereoretically, it has to sound worse because of that overlap.
    2) Trying to "match" the crossover slope in your receiver/pre-pro with the natural roll off of your mains at low freq may results in the same effect of cascading filters. You essentially have 2 roll offs that are interacting.
    3) Depending on what kind of music you listen to, there may not be much below 40 Hz anyway. (Rock, for example.)
    But bottom line? You have to judge for yourself! [​IMG]
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  15. Chris PC

    Chris PC Producer

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    I'll just keep playing with it. I will be talking to some PSB speaker techs who are very familiar with Marantz (Lenbrook, where PSB speakers is headquartered in Pickering, also distributes Marantz receivers). I'm going to hammer them (politely) about the 100 hz crossover and ask as much as I can about acheiving the best sound.
    Today I'll be bringing home a pair of PSB Image 6T's to demo until Monday, so that should prove interesting. 5T's or 6T's......hmmmmm.......that is the question, among others of course.....
     

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