How do I set my sub best? Help.

Discussion in 'Archived Threads 2001-2004' started by Luis M, Jun 11, 2002.

  1. Luis M

    Luis M Second Unit

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    How can I squeeze the best possible sound out my sub?
    Should I set the sub to max and lower the signal from my receiver or should I set my sub very low and gain with the receiver? I would think sending too much signal from my receiver could introduce noise and distortion but wouldn't it be the same if I drive my sub's amp to the max?. Maybe a compromise between the two is the best way to go but who knows? Any help is welcome.
     
  2. Barry BB

    Barry BB Stunt Coordinator

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    I will give you a general answer but if you do a forum search or use Avia or Video Essentials you will get much more info than I am giving you here.

    Let the receiver do the crossover by setting your sub's crossover bypass switch or if no bypass switch set the sub crossover to the max position. Set the receiver's crossover to 80db. The receiver's sub gain setting should be set during calibration. With Avia you want to be around 85db on your SPL meter. With VE you want to be around 75db. And the location of your sub will make a big difference so you'll have to experiment with sub placement.
     
  3. David Judah

    David Judah Screenwriter

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    And if you want to go to the next level, get an RTA program(there are shareware downloads available), a disc with test tones(create your own or purchase one), and do some in-room measuring. Once you find a decent spot you can then invest in an EQ for your sub and tame the peaks to get a more even response through the sub's frequency range.

    Do a search with BFD, ETF, or Spectra, if you want more info.

    Good Luck,
    DJ
     
  4. Bill Kane

    Bill Kane Screenwriter

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    Luis,
    Here's my take: you are right that it's a two-knob dance between the sub amp and receiver line-level sub output setting. There's no "correct" setting because of yr amp's characteristics and the sub's.
    HTF administrator Vince Maskeeper has posted often he is a believer in setting sub amp volume or gain control as MAX as possible, thus less distortion from running the rcvr's sub output nearly full. He's coming from his work with pro amps and performance bands, I believe.
    The other end of this balance is to end up with the rcvr's sub setting somewhere below the midway point to give you adjustment room during playback. My Yamaha sub level ranges -20 to 0. I am calibrated at -15.5 amp level for 85dB reference, and my SVS amp knob ends up at one position past the midpoint.
    There is debate about boosting sub reference using the RS meter (correction factor), but SVS for one recommends no more than a 4dB boost when setting reference. Set the sub at 85dB with the test disc and let your ears tell if that's enough seamless bass. For sub placement, the usual starting point is a front corner.
    bill
     
  5. Luis M

    Luis M Second Unit

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    Thank you guys for the help, I guess I will try the sub to the max and then from there calibrate the system.
    There is a chance though that with the sub at max volume the signal will be too high even with the reciver at a minimun gain, in that case I lower the sub's volume until I get the ideal reading right?
     
  6. Barry BB

    Barry BB Stunt Coordinator

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    Luis

    I re-read your question and my answer and I may have mis-interpreted what you were asking. You want to set the crossover to max but you don't want to set the sub's amp volume to max. You'll need to balance the sub's amp gain with the receiver's sub setting. To start try turning the sub's amp volume to about 1/2 to 3/4 and then calibrate from there. Adjust the receiver's gain setting and the sub's volume in tandem until you get to where you want to be.
     
  7. jeff lam

    jeff lam Screenwriter

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    The amp's level should only be set to MAX if you are using a PRO Audio Amp!!! The standard plate amp as a much lower input voltage and a much higher input impedance. You would surely clip the plate amp far before you reach MAX level on it with a normal receiver's sub output.

    This is my method:

    Set the receiver/preamp's sub output to 1/4 max output level (if your level ranges from -20 to 0, use -15, if your level range is from -10 to +10, use -5, etc.). This is recommended because the sub output from the receiver/preamp can introduce distortion from 50% and up depending on your reference level and the type of receiver. Typically you don't want this level to be more than 1/2 way up at any time. Once the receivers level is set, slowly bring the sub amp gain/volume level up till you measure proper calibration. This could be 1/2 way up, 1/10th way up or it could be all the way up. It's very important that you use VE or avia and a SPL meter to measure this.
     
  8. Bill Kane

    Bill Kane Screenwriter

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    Luis, your post no. 5 is on the right track, and the rest of us advisors here seem to be on the same page, too.

    Most likely, your sub amp level will NOT end up at MAX, given the goal of keeping the rcvr's line-level sub out level somewhere below its halfway range.
     
  9. Luis M

    Luis M Second Unit

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    My sub amp ended up three quaters up and the receiver ended at (-12) but that is as low as the receiver goes. Is it a good idea to keep the receiver's signal at its lowest level?
     
  10. Vin

    Vin Supporting Actor

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  11. Chris Tsutsui

    Chris Tsutsui Screenwriter

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    On my sub I set the gain so that when I watch movies I raise the volume on the pre/pro to max. Then when I listen to music in 2.1 I lower the volume on the sub down to the right setting (adjustments are digital and reproducable).

    This way I never have to touch the plate amp and just adjust settings on my processor. It's also harder to recreate the same volume levels on a knob.
     
  12. Luis M

    Luis M Second Unit

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    I will lower the sub's amp a couple of notches then to have some room to play with in the receiver. Thank you all.
     

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