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I'm a novice, help me set up my new Sub.

Discussion in 'Subwoofers' started by monkeyWRENCH, Sep 14, 2002.

  1. monkeyWRENCH

    monkeyWRENCH
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    I just bought the MJ Acoustics Pro 50 and I have no idea on how to set it up properly to get the best sound out of it.

    Currently, all my speakers are set to 'small' on my 1802, and on the back of the sub, there is a 'freq' dial ranging from 40Hz to 240Hz (LFE)... this is currently sitting at the "12 O'clock" position. Is that OK?

    My front speakers are 8.3's (frequency response 40Hz - 20kHz)

    Any advice would be appreciated.
     
  2. Jase

    Jase
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    Hi

    If you have all speakers set to small, all bass to sub, set the crossover on the sub to maximum (240Hz). Your amp will be controlling the cutoff to the speakers. Try the sub volume set to around a third and adjust to your taste via the amp (SW channel). Also play around with the Phase setting to see which is best.

    If you have a Sound Meter then balance all your channels to 75db, if you don´t, you´ll have to do it by ear.

    Another alternative would be to set the Front Left & Right speakers to Large, all others to Small and bass to LFE/MAIN. Then set the crossover on the sub to around 40-50hz.

    See which settings give you the best results.:)
     
  3. monkeyWRENCH

    monkeyWRENCH
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    Thanks, Jase! I'll have a play around with the settings you've suggested. :clown:
     
  4. Dom H

    Dom H
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    Here's how I setup my Pro50.

    Set all speakers to small with an 80Hz x-over. Adjust the subs freq dial to 240Hz (this removes the subs xover relying on the amps setting) Set the phase to the 12 oclock position.

    Now to calibrate, go to the levels setup screen on the amp, change the tone to 'manual'. Adjust the normal speakers to 75dB. Set the subs volume to about 12 oclock to start with and the amps SW level to its lowest -12dB (the idea is to have the subs volume as high as pos and the amps as low as pos) Leaving the amp SW setting at its lowest, slowly adjust the sub until the meter flicks around the 70-75dB mark (it wont stay still cos the tone changes)
    This will give a lower than 75dB reading which compensates for the meters innacuracy at low frequencies.

    You can then fiddle with the phase switch (but u dont have to), twiddleing mine reduced a peak around 60Hz (see the excel sheet in my review post, all done with a tone cd and spl meter)

    You can also try moving the sub around the room to try and achieve a flatter response (you need some test tones and an spl meter)

    Feel free to fiddle with the sub volume (on the amp if you find that easier) if you prefer a little more or less, remember calibrating a sub with a meter isnt an exact science, its much less accurate than calibrating the mains with a meter so adjust away. I find upping the SW level on the amp by 4dB or so helps non-dvd sources (tv/radio etc.) in the low end as they are usually a little lacking.

    Hope that helps.

    Dom.
     
  5. paulr

    paulr
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    Can you get someone in to do this and how much do you reckon it will cost?
     
  6. Dom H

    Dom H
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    Paul pick up a SPL meter for £25 and I(we) help you do the rest, it's not difficult.

    Has anyone got the url for the place selling spl meters (cornwall electronics?)
     
  7. paulr

    paulr
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    Dom..how much difference will setting up your sub properly actually make to the sound?
    Basically i just set mine to what sounds right:rolleyes:
     
  8. Grimley

    Grimley
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    I've just bought this sub today, & I've done what you have suggested. But alas, I have no SPL meter!
    What I do have is this DVD & T2 R1, which I understand has a THX optimiser.
    & Sony 940. Crossover freq. for front centre & rears set to 90hz
    (doesn't do 80hz) sub is located about 7' away from listening postion against a wall & room size is 10' x 13'.
    Suggestions please or have I done the setup right?
    I thought also that setting the cutoff freq. to it's highest setting on the sub would give away its position, which I'm told is not the thing to do when setting up a sub.
    Any advice would be appreciated.Cheers.
     
  9. Dom H

    Dom H
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    Depends how far off you were on your first attempt! :)

    Setting the level of the main speakers to be somewhere near level isn't too difficult going by ear but I wouldn't attempt doing a sub without. I've never heard a sub setup by ear tho, mine was callibrated straight away.

    I did setup my mains without an spl meter initially and when I bought one and checked he levels I was dead on for all 4!! A little miffed I'd spent £25 to tell me this mind :p

    I'd say it's essential for setting up a sub.
     
  10. Ian J

    Ian J
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    I normally setup subs by ear as I find the SPL meter too unreliable for subs.

    Grimley,

    You don't say what speakers you have as setting the cutoff on the sub at 90Hz could be too low if you are using small satellites.

    The bass coming to the sub will be governed by the amp crossover setting which is why people turn the sub crossover to max and let the amp manage everything.

    Paul,

    If it sounds right to you - it is right. It may sound silly but fiddle with the settings so that you know what wrong sounds like and it becomes easier for you to see when it is right.
     
  11. Grimley

    Grimley
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    Apologies Ian,
    Tannoy M2 fronts,
    Tannoy M1 Rears,
    Jamo centre 100 MK2.
     
  12. Ian J

    Ian J
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    Grimley,

    90Hz should be OK as they are full range speakers and not satellites at the front. Lower is best but if 90Hz is as low as it goes that will do.

    Try moving it away from the wall a couple of inches to see what difference that makes. It might sound better or it might not but your ears will tell you.
     
  13. Grimley

    Grimley
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    I'll try that, thanks for the advice Ian.
    by the way, I see the feet can take spikes & they are available as accs. according to the MJ web site.
    however, I do have some spikes from my old speaker stands (Heybrook hb1s stands) & it looks as though they will fit.
    IYO, will this improve the sound?
    Cheers.
     
  14. Ian J

    Ian J
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    It depends on what the sub is currently resting on (don't know it that well). If it has good solid rubber feet, that should suffice but if not try the spikes.
     
  15. Grimley

    Grimley
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    Ian,
    it's sitting on foam backed carpet at the moment with about
    10kg of books & mags on it to make it more stable,
    even though the floorboards underneath are level.
    Putting weight on a sub seems to improve the sound quality for some strange reason, it did with the old sub.
     
  16. Ian J

    Ian J
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    The sub has thick wooden feet already which is probably better than adding spikes. It would probably sound better on a solid base rather than firing into a carpet. as it is fairly compact you may get away with a small paving stone.
     
  17. Grimley

    Grimley
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    Thanks for the advice Ian, I'll have to try the paving slab tip one day. (I would be playing 20 questions with the female members of the household if I bought a small paving slab into the house, thats too much grief for me!)
     
  18. Ian J

    Ian J
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    One of the small ones would do and you can buy them in different colours so that it would match the carpet. Cutting it exactly to shape is another option so that none protrudes and you could always cover it with a light fabric.

    I have been meaning to do it for a while but have recently had an attack of bone idleness so haven't got a round to it.
     

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