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Active or Passive subs?

Discussion in 'Subwoofers' started by Mark Ward, May 15, 2002.

  1. Mark Ward

    Mark Ward
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    I another Forum Garmtz said:-
    I thought I'd reply to this part in the "Speakers/Subs" forum as I may end up taking the thread off topic otherwise....

    I'm currently using an M&K V75 Mark II Sub which I find fantastic in my current room. It's obvious to me it won't suit my new room.

    I recently bought a B&W THX set that contained 2 X PCM8 Passive THX subs. My thoughts were to use these, powered with my Denon POA-T10 for my very much larger new room.

    I'm currently EBaying the FCM8's THX monitors that came with them. Do you think I'd be better off Ebaying the PCM8's as well and buying passive subs (Servo 15's?) instead? The new room is a MASSIVE 42ft X 20ft (13M X 6M) X 2 storeys high.

    Mark.
     
  2. Nic Rhodes

    Nic Rhodes
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    Mark

    This one is really down to money. Personally I prefer active subs with their built in amplifiers. Amplifiers for subs don't need quite the same qualities as a full range audio amplifier and therefore can be made cheaper. How many 400w amplifiers do you know for £500 but many subs have them?

    Passive subs need serious amounts of power to work well and this means good quality amplification (read very expensive). You also loose out on the likes of servo control as well.

    However saying all that the most expensive subs around need separate amplifers. Stereophile class AAA components have many in there. These are really SILLY money and I have never seen ANY in the UK for sale. (> £6k + amplifiers!!). Friends in the US tell me they prefer HSU, Velodyne and Paradigm top subs anyway!

    Iwould stick with the usual favourites.
     
  3. Ramius

    Ramius
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    Hi

    I don't understand the statement-

    "Don't leave a power amp channel unused for a passive sub. Just use an active one, which is superior anyway."

    Is he saying 'don't use a spare amplifier channel to drive a passive sub. Leave it unused and just use an active sub which will be superior.' ?


    Anyway, there's nothing wrong with using a spare amp channel to drive your sub as long as it is capable.
    If not www.bkelec.com have cheap, very good quality (toroidal transformer etc) 'raw' mono amps.

    Or you could look at pro offerings from www.crestaudio.com www.qscaudio.com www.crownaudio.com and others.

    If you want crossover & phase adjustments you'll need a sub plate amp, BK have several. But you can't beat the power/cost ratio of BKs raw amp modules.

    Cheers
    Boris
     
  4. Mark Ward

    Mark Ward
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    Hi Boris

    I currently have 2 X B&W PCM8 THX Passive Subs that came as part of a large secondhand HiFi purchase I made. I also have a spare Denon POA-T10 THX Amp lying around.

    I had thought from previous discussions (mainly in Canada!) that passive subs were better performers.

    My question was really to ask whether I should sell my 2 enormous THX passive subs & THX amp and buy equally huge Servo 15's instead.

    As I'm currently auctioning the matching B&W THX monitors it would be a very good time to sell them right now if this is better.

    If there is not much to choose between Active and Passive then keeping the B&W subs would be preferred as I already have them.

    Mark.
     
  5. Reiner

    Reiner
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    Passive subs are "better" if wired parallel to the front speakers for stereo duties but that might not suit well to AV amps as they put a lot of strain on them.
    Thus active subs connected to the line level are preferred / recommended.

    But I don't see any problem to use the POA-T10 and the two passive subs to make it an active setup (wired from the subwoofer out of the AV receiver). As the AV amp/receiver will take care of the bassmanagement then it should be no problem at all.

    Though note that active subs usually have a seperate volume control and phase select which makes it easier to integrate them.


    Bottom line: use what you have and see how it performs. If it's no good you can still change it later.
     
  6. Mark Ward

    Mark Ward
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    This is what I wanted to hear! :D

    Thanks,

    Mark.
     
  7. Ramius

    Ramius
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    I agree, use them.

    Due to your large room you might find it advantageous to run them next to each other or stack them. Get the drivers as close to each other as possible. This will yield the maximum possible output.

    Cheers
    Boris
     

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