1. Join Now

    AVForums.com uses cookies. By continuing to use this site, you are agreeing to our use of cookies. Learn More.

How to set up a sub woofer?

Discussion in 'Subwoofers' started by Brogan, Dec 29, 2003.

  1. Brogan

    Brogan
    Well-known Member

    Joined:
    Oct 9, 2003
    Messages:
    7,476
    Products Owned:
    0
    Products Wanted:
    0
    Trophy Points:
    106
    Location:
    Cary, North Carolina
    Ratings:
    +481
    I have a paradigm PS1000 which has sub-sat phase alignment, cut-off frequency and level controls.
    The manual suggests playing some music and setting the controls based on the instructions therein.
    However, will this then have an adverse effect when using the MCACC on the AX5?
    Basically, what is the best way to set the sub up?
    Should I just set all controls to mid and let the amp sort it out or should I set the sub up first using a simple stereo source and then run MCACC?
    Alternatively, should I set some of the settings based on my other speakers and the amp specifications - e.g. the cut-off frequency?
    Currently I don't think I'm getting the best from the sub as the amp has decided it's 3.7 metres away (when in fact it is only 1.5) and set the channel level to -9dB.
     
  2. Andywilliams

    Andywilliams
    Active Member

    Joined:
    Sep 27, 2002
    Messages:
    2,077
    Products Owned:
    1
    Products Wanted:
    0
    Trophy Points:
    51
    Location:
    notts.
    Ratings:
    +63
    Hi brogan
    Iam not familiar with the pioneers mcacc set up but have you got an spl meter to check what the amps done after mcacc set up.I calaberated my speakers to 75db including the sub it is set at -5db on the amp which is what was recommended.Ive found with music it sounds better at -8db on the amp.So if you havent got a spl meter get one and set it up yourself then see which sounds best to your ears.
    cheers Gonzo.:)
     
  3. Brogan

    Brogan
    Well-known Member

    Joined:
    Oct 9, 2003
    Messages:
    7,476
    Products Owned:
    0
    Products Wanted:
    0
    Trophy Points:
    106
    Location:
    Cary, North Carolina
    Ratings:
    +481
    AFAIK, the Pioneer MCACC system performs the same function as an SPL meter and probably does it better as it covers 5 frequency bands (just guessing here).
    I would therefore be reluctant to substitute a superior system for an SPL meter and my ears (which are pretty much useless these days...)
    I don't actually use the sub for music as I have full range floorstanders and I listen to music in DIRECT mode which is plain old stereo.
    The sub is only used for movies.
     
  4. Ian J

    Ian J
    Banned

    Joined:
    Aug 6, 2001
    Messages:
    25,529
    Products Owned:
    0
    Products Wanted:
    0
    Trophy Points:
    166
    Ratings:
    +4,906
    How can the MCACC system calibrate a subwoofer better than an SPL meter when it can't even set the distances correctly. I would be very surprised if the correct level for the subwoofer is -9db and would agree with Gonzo's suggestion that using an SPL meter is best.
     
  5. Brogan

    Brogan
    Well-known Member

    Joined:
    Oct 9, 2003
    Messages:
    7,476
    Products Owned:
    0
    Products Wanted:
    0
    Trophy Points:
    106
    Location:
    Cary, North Carolina
    Ratings:
    +481
    Well I guess as the sub is hidden behind the sofa and bass is omni-directional then it's no surprise the amp/mic has a job identifying exactly how far away/where it is.

    But, getting back to main topic of the post and assuming I don't have an SPL meter, which I don't....
    Should I set the sub according to the sub manufacturer directions and then run MCACC or just set the sub controls to the middle setting and run MCACC?
     
  6. ancientgeek

    ancientgeek
    Guest

    Products Owned:
    0
    Products Wanted:
    0
    Ratings:
    +0
    I have only common sense to rely on, not in-depth knowledge, but this is what I think and did.

    cutoff
    You are using the amp to do the sub/sat crossover function, so it makes sense to set the sub cutoff where it doesn't do anything - ie higher frequency than the amp's crossover point. Might as well set it to its highest frequency - it's not doing anything. Mine in fact removes t he crossover entirely at its highest setting.

    gain
    If it can't make the sub loud enough, MCACC will cut back the volume of all the other speakers. Set up MCACC with no sub and see what output levels it has set for the other speakers. Turn up the sub gain far enough that MCACC doesn't cut back all the others but not so far that MCACC has to cut the sub back by lots. Midpoint is where I left mine.

    phase
    If it's just a normal/reversed setting, and the sub is correctly wired, I can't see why you wouldn't leave it at normal.

    sub distance
    If your walls/floor/ceiling are for example on average reflecting 70% of the sound energy arriving at them, then two thirds of the sound at your ears is coming indirectly from the source.

    If there's a sofa between your sub and the MCACC microphone, then the principal sub energy arriving at the microphone may well be travelling 3.7 metres to reach your listening position, and the corresponding delay set by MCACC is the correct one.

    If you want/are able, experiment with position of sub in the room (running MCACC at each new position first). Listen for acceptable integration with the other speakers especially at the listening positions where you didn't have the MCACC microphone.

    In use, possibly tweak the sub gain to please yourself for particular source material, but set it back to the MCACC setting afterwards.

    Alternatively just forget the whole thing and watch the movie.
     
  7. buns

    buns
    Banned

    Joined:
    Apr 29, 2001
    Messages:
    6,066
    Products Owned:
    0
    Products Wanted:
    0
    Trophy Points:
    58
    Location:
    Belfast
    Ratings:
    +1
    Without knowing the exact details of the pioneer system, it is hard to say. But what is easy to say...... set the sub up as suggested by the manufacturer, then let the pioneer system do its magic.

    I wouldnt worry too much about what the system actually comes up with, as suggested, there are many reasons why the numbers may seem incorrect. It may be right (relative considerations) or it may be wrong, but you have no way of checking it so why stress? Just set it up and let it fly unless it bugs you!

    ad
     
  8. Stellavision

    Stellavision
    Active Member

    Joined:
    Apr 7, 2003
    Messages:
    2,190
    Products Owned:
    0
    Products Wanted:
    0
    Trophy Points:
    51
    Location:
    Southsea, UK
    Ratings:
    +75
    I posted quite an in depth post once a while back about setting everything up with MCACC, receiver test tones and Avia test tones.
    My conclusions were that MCACC did a surprisingly OK job of calibrating my speakers, but did need some tweaking with an SPL meter to get the levels just right. I always finish up making final tweaks using AVIA as this seems to be the most accurate method.
    If you want to be ultra fussy you would measure the distances from listening position to each speaker to determine the delay required. I personally don't think that the inch or so here in there that MCACC loses is worth worrying about.
    Whether you use MCACC or an SPL meter to set up your sub, you may need to simply treat it as a guide. Your room may produce inconsistancies which make certain frequencies too loud / quiet or significantly imbalanced.
    There's also the matter of personal preference to take into consideration.
     
  9. Brogan

    Brogan
    Well-known Member

    Joined:
    Oct 9, 2003
    Messages:
    7,476
    Products Owned:
    0
    Products Wanted:
    0
    Trophy Points:
    106
    Location:
    Cary, North Carolina
    Ratings:
    +481
    Thanks guys.
    Quite a lot to consider there so I'll give it all try tomorrow....too busy right now giving the wife a pasting...at Worms 3D before you say it...:D
     
  10. eviljohn2

    eviljohn2
    Well-known Member

    Joined:
    Jul 8, 2002
    Messages:
    7,529
    Products Owned:
    0
    Products Wanted:
    0
    Trophy Points:
    86
    Location:
    Near London.
    Ratings:
    +208
    This is not true at all! Bass frequencies are as "directional" as any other sound waves, it's just that the human ear cannot pinpoint the location as easily.

    What Hi-Fi? has a lot to answer for by dumbing down to the extent they do - they've caused more confusion than if they'd just said what I did!
     
  11. Brogan

    Brogan
    Well-known Member

    Joined:
    Oct 9, 2003
    Messages:
    7,476
    Products Owned:
    0
    Products Wanted:
    0
    Trophy Points:
    106
    Location:
    Cary, North Carolina
    Ratings:
    +481
    Therefore effectively making them omni-directional or perhaps less directional than higher frequencies to both the human ear and an omni-directional microphone...
     
  12. Andywilliams

    Andywilliams
    Active Member

    Joined:
    Sep 27, 2002
    Messages:
    2,077
    Products Owned:
    1
    Products Wanted:
    0
    Trophy Points:
    51
    Location:
    notts.
    Ratings:
    +63
    Hi Brogan
    It is worth buying a spl meter just to tweek your system set up and at only 25 quid isnt going to dent your wallet.
    Hope you didnt take it the wrong way when i said about using the spl meter as it wasnt meant to.
    Cheers Gonzo.
     
  13. Brogan

    Brogan
    Well-known Member

    Joined:
    Oct 9, 2003
    Messages:
    7,476
    Products Owned:
    0
    Products Wanted:
    0
    Trophy Points:
    106
    Location:
    Cary, North Carolina
    Ratings:
    +481
    No offence taken Gonzo and in fact it was good advice and I am considering doing just that as it is obvious the MCACC system, as good as it is, isn't perfect.
    I ran MCACC yesterday 4 times in succession and there were slight variations in the results each time so an SPL meter would be a good way of double checking.

    What I have done though is set up the sub according to Ancientgeek as his suggestions were kind of obvious after I read them and then run MCACC.
     
  14. eviljohn2

    eviljohn2
    Well-known Member

    Joined:
    Jul 8, 2002
    Messages:
    7,529
    Products Owned:
    0
    Products Wanted:
    0
    Trophy Points:
    86
    Location:
    Near London.
    Ratings:
    +208
    Effectively, yes, but there's still an important distinction that's worth remembering. The microphone will probably not be as "omni-directional" but SPL meters become very inaccurate for lower frequencies anyway.
     
  15. Jeff

    Jeff
    Well-known Member

    Joined:
    Jul 13, 2000
    Messages:
    5,489
    Products Owned:
    0
    Products Wanted:
    0
    Trophy Points:
    106
    Location:
    Basingstoke
    Ratings:
    +256
    When calibrating the sub with an SPL its very important to take measurements across multiple frequencies (the more the better). If you are doing the calibrarion using a standard single frequency test tone the chances are that your sub isn't setup correctly. The most important frequencies to get right are those around the crossover point.
     
  16. JoeyJoeJoe

    JoeyJoeJoe
    Guest

    Products Owned:
    0
    Products Wanted:
    0
    Ratings:
    +0
    Here's my tuppence worth if it is actually worth anything to you :)

    I have a Pioneer VXS-D912 and it has automatic MCACC which I have used, IMO, with some success. My speakers are as follows;

    Mordaunt Short 902 [Front], 905 [Centre], 302 [Rear] and a Vibe Alpha One Sub. I first used MCACC with all speakers set to small and then with the fronts and centre set to large. The difference with the latter was very impressive. I have a square room with laminate flooring which is approx 12 feet square. Here are the results with the auto MCACC set up.

    Front R [+0.5db] Distance = 2.2m
    Front L [0db] Distance = 2.1m
    Rear R [+2.5db] Distance = 1.7m
    Rear L [+2.0db] Distance = 1.6m
    Centre [-2.5db] Distance = 2.1m
    Sub [+7.5db] Distance = 2.0m

    At a guess, I would say that the distances are pretty much spot on. The sub is set up as follows; Phase set to 0 because the sub is in a corner alongside my seating position facing diagonally towards the centre of the room. I was told that if the sub is in front of you, to set it to 180 or whatever the highest setting is. Crossover is set at 150hz on the sub but *** on the amp. Volume on the sub is a just under one third.

    The settings that I had used previously were well off now that I realise that you should actually 'feel' the sub rather than 'hear' it.

    Anyhoo, this works for me but probably not for many others as there are so many variations in room sizes etc etc.

    PS. Forgot to mention that putting a scrap piece of carpet under the sub has made a world of difference too. I posted a thread a few weeks ago saying that I had problems with my sub 'rattling'. The vibrations were going through the floor and back to the sub because of the laminate flooring :rolleyes:
     
  17. Stellavision

    Stellavision
    Active Member

    Joined:
    Apr 7, 2003
    Messages:
    2,190
    Products Owned:
    0
    Products Wanted:
    0
    Trophy Points:
    51
    Location:
    Southsea, UK
    Ratings:
    +75
    Not neccessarily. The normal phase starting point on any sub is usually suggested to be set at 0 by the manufacturers. This is usually suggested with a forward sub placement in mind. Certainly the manual on my B&W ASW675 suggests their reccommended position for the sub is as near to the fronts as possible, with phase set to 0. However, the old room thing comes into play again and where it is also most practical for you to postion your sub. Each enviroment is different.
    Avia is an excellent disc for setting up a subwoofer and has some very useful test tones for setteing the correct phase on your sub.
    Again this can be aided by the use of an spl meter and finding which setting produces the most bass.
     

Share This Page

Loading...