powered speakers

Discussion in 'Speakers & Subwoofers' started by Nikko, Jul 11, 2006.

  1. Nikko

    Nikko Agent

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    I was talkig to some guy at a local retailer about powered main speakers and having to split the LFE channel to actually get the bass to them. He was saying that everytime you split the LFE channel you loose 3db of sound. So with the def tech having powered mains, centers, and surrounds you end up loosing 12db of bass in a 5 speaker set up.
    So my question is, how true is this and does it make buying powered surrounds not worth it? And if my crossover point for the LFE channel is at 80hz and the crossover piont of the surround bass-to-mid is at like 200hz, is all the sound from 80-200hz still powered?
     
  2. John Garcia

    John Garcia Executive Producer

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    You do lose some strength when splitting, but you would have to split the signal quite a few times before you lost 3dB of signal, IMO. If you use a single Y, you are definitely NOT loosing 3dB.

    I don't see what powered speakers and LFE have to do with each other? Do you mean speakers that have powered subs (with an LFE input) or ones that are simply self powered (active)? If using a sub, the LFE is still directed to the sub, and has nothing to do with the other speakers, which can still be powered. If using the preamp outs, you would not be sending LFE to any of the other speakers either, just each channel's information. If you are saying each speaker has a powered sub and you want to send the LFE to each speaker via splitters, I still don't think that would result in a loss of 3dB, but it probably isn't a good idea - you'd be better off with a subwoofer.
     
  3. Wayne A. Pflughaupt

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    Nikko,

    John’s right – you’ll get a slight loss with a signal split, but nothing approaching 3 dB-per. I’d be surprised if you lost 3 dB total splitting out to all five channels. Most receivers have an LFE level adjustment that will minimize the problem.

    Regards,
    Wayne A. Pflughaupt
     
  4. Nikko

    Nikko Agent

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    ya, I mean surrounds with a powered sub. They have two 6.5" powered subs in each (bipole). So I know that to get the low frequencies to the speakers I must have an LFE channel plugged into them. They are supposed to reach down to 31hz. And if I don't run the LFE channel to them, is the bass from the LFE cutoff to the crossover still powered?
     
  5. LanceJ

    LanceJ Producer

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    If you want the LFE signal to go to the front mains without messing with extra cables, IMO just program the receiver for "no subwoofer" and "fronts/large".

    As far as directing the LFE signal to the surround speakers.....why would you want to do that?
     
  6. Nikko

    Nikko Agent

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  7. John Garcia

    John Garcia Executive Producer

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    DefTech is well known for exaggerating (or rather misrepresenting) their low end extension. The number given is likely -10dB, where the normal spec is -3dB. LFE and bass are two different things. LFE is the .1 channel, and is not present on any other channels, and as a result, should not be sent to the other speakers. What you want to send them is a full range signal or one that is crossed over as low as possible, say at least 80Hz or lower.
     
  8. Nikko

    Nikko Agent

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    actually, it is best if rather than have a .1 channel, you have a .2 or .3 channel. This allows for a much more even and controlled distribution of bass without as many room interferences.
     
  9. John Garcia

    John Garcia Executive Producer

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    Multple subs at multiple locations causes MORE interaction, not less, and makes calibration of the sub channel much more involved. Tower speakers are really not going to hit the lowest of the lows the way a good sub will because they are really not designed to do so in most cases.
     
  10. LanceJ

    LanceJ Producer

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  11. John Garcia

    John Garcia Executive Producer

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    CV still don't hit the below 20Hz stuff, and I know you aren't suggesting they sound good while trying...[​IMG]
     
  12. LanceJ

    LanceJ Producer

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    I don't even own CVs, but from an audio perspective things like this just bother me.

    John: have you even heard this series of CVs (not neccessarily this one particular huge model)?

    And if someone really gets into audio, they will have noticed these CVs use a completely different midrange and tweeter compared to their previous models, the two drivers that reproduce the spectrum of sound that seems to cause the most displeasure with CV's detractors. FYI: I've never seen CV use a soft-dome tweeter, soft domes usually having some of the most restrained & pleasant high frequencies among such tweeter designs. And on a more obscure note, the people responsible for this series used to work for Revel and NHT, two highly respected loudspeaker manufacturers.

    While these loudspeakers are tuned - relatively speaking - more for music than HT, I bet they (and their single 15" cousin) could still rattle the hell out of the dishes in someone's cupboards with those many, many movies that DON'T feature sub-20Hz bass, and instead "only" employ the bass frequencies above 20Hz which can still cause a major physical sensation......and we all know speakers don't just suddenly shut off immediately below their stated bass spec (even though CV didn't give a +/- dB frequency rating, I find it hard to believe a design using two 15" woofers in that large an enclosure can't make it down to a solid 24Hz. Because if a Large Advent from 1975, with a single 10" woofer in a sealed 1.5 cu/ft box, can get to 35Hz............). And with their high efficiency rating, I'm sure they don't require a pair of Krell 500W monoblocks to do this.

    ************************************************** **

    In this present situation where so many people aren't buying ANY audio system for their expensive new HDTV*, telling people that they HAVE to have a subwoofer that goes below 20Hz for the tiny minority of very recent movies that include that kind of radical bass IMO does a disservice to the newbies reading this forum AND the companies that sell subwoofers. Why? Because when faced with the cost and physical requirements for a sub like that, I have a strong feeling that many of them will just decide to buy no subwoofer at all and use their mains if they're large enough......or just blow off the idea of an HT system altogether. When you see posts on this very forum saying that the writer thinks a bookshelf speaker with a 6.5" woofer is a "large" speaker and takes up too much space, you gotta think that extends to other parts of an HT system.

    And when I started seeing posts pushing the idea of two subs to casual HT owners, I laughed my butt off. Two of them?! It's hard enough for an HT expert to get one sub smoothly integrated into a system! I don't doubt it when Dr. Floyd Toole says two subs have the potential to create smoother bass coverage in a room, but that takes loads of experimentation and tweaking to do so and that's if you even have a room where you have the freedom to do so i.e. not a living room with its furniture placement constraints, windows, entry hallways, vaulted ceilings, wife's decorating concerns, etc.

    I honestly have no problem with people being really into HT and bass, but jeez, y'all make it sound like bass is a yes/no, black/white situation i.e. if your system can't reproduce X frequency at some crazy SPL level, then you don't own a "real" HT system and might as well just listen to the TV's speakers instead. [​IMG]

    * scary statistics: according to a report published by the Consumer Electronics Association, in 2005 sales of portable audio gear were nearly double that of home audio separate components. Double!! And in the same time frame sales of HTiBs - you know, the systems that take a whole 5 minutes to set up - dropped 16% compared to the previous year.
     
  13. John Garcia

    John Garcia Executive Producer

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    I would definitely not say that below 20Hz content is limited to a "tiny" number of movies. That content is now found in so many movies that a decent sub should be considered practically a must (it IS a must in my book for a serious HT system). A single, good sub is sufficient, and for the average HT-novice is likely the best course in terms of calibration and integration. In my 2ch setup, I have no sub...don't need it.

    I have not heard the latest generation of CVs, but I have also never heard CVs that were good for anything besides being loud, so it is entirely possible they have improved of late. A 15" driver that is not designed to go that low is still not going to give you those lows. Those drivers are more likely than not designed for SPL, not extension.

    My main reason for recommending a decent sub is because a sub is still far more efficient at handling the low frequencies rather than using your receiver to power all those low end hits. This removes a lot of strain off your receiver, especially compared to trying to drive something like a dual 15" beast even if it isn't tuned to go that low; it will still try to reproduce those frequencies that are below its capability - even a bookshelf will do that.

    There is a BIG difference between good 25Hz performance and good 20Hz performance, IMHO. Good output at 20Hz really does lend a lot of realism to the movie experience. I agree with you though, it is up to the individual to choose for themselves if they want a sub. I will still make my recommendations based on what I feel will give even a novice the best results.
     
  14. LanceJ

    LanceJ Producer

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    Appreciate the detailed response John.[​IMG]

    Though I just realized something about the link I posted: I was being a bit humorous while forming my post (i.e. I know *very* few people will tolerate a 111lb/4ft+ loudspeaker) & didn't remember that CV has their site set up so that linking directly to a specific model or series takes some farting around with HTML so for people who didn't know what series I was whining about [​IMG] here's the right one: CLS Series
     
  15. Jimmy Nugent

    Jimmy Nugent Stunt Coordinator

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    I'm actually in negotiations for a complete home theater upgrade featuring a deftech setup, courtesy of a fallen oak tree.

    I'm considering the PowerMonitor 500's as fronts with a 2300 for a center, two bp2x's for surround and a supercube III sub- all fed by a Pioneer 84txsi (in a small room- approx. 11' x15').

    Would I gain all that much by hooking up the LFE inputs on the 500's or would I be okay just amplifying the bass signal sent to the fronts via standard speaker wire using the 500's built-in powered amps?

    Thanks-

    Jimmy
     
  16. Nikko

    Nikko Agent

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    thanks for the help guys. Right now what I am doing is driving down to san francisco and bring a bass test/theater test cd with me. This is some real tests and I am going to just demo as many differant HT and Subs as I can. I already of a list of a good 5 stores that will allow me to test many of the good names. It'll be a few weeks before time allows for me to make the trip, but I'll update ya on what I find out.

    And I have no size limitation on my speakers, I actually prefer bigger towers. I want GOOD speakers that I can power with just a 100w/c amp. I will be using 75% HT and 25% Music. And I don't really like the sound of horn tweaters that much, just not for me. But GOOD, deep, fast, and clear bass are all very important to me
     
  17. John Garcia

    John Garcia Executive Producer

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    Head over to Berkeley and check out Music Lovers.
     

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