Tips on calibrating my new Sub

Discussion in 'Archived Threads 2001-2004' started by Doug_Z, Jan 8, 2003.

  1. Doug_Z

    Doug_Z Agent

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    My single Ultra has arrived! I only have 2 corners in my 16x16x8 HT ONLY room. The room has an open kitchen to the left and only a 3'wall separates the 2 rooms. The kitchen is 16x15x8. There are also 2 open doorways. One opens into a hall. The other into a living room.I have started, at the suggestion of SVS, by putting the sub in the left rear corner about 6-7 feet from the couch.I will probably also try it in the front corner behind my foor standing speakers since I am detecting some localization. The localization lessened when I reversed the speaker connections.In the front corner the sub would be about 10-11' from the listeners.
    My real question is about calibration.The Samson instructions say to "Apply an input signal to the S1000 at or about 0 dBu" I have no idea what that means!Can someone explain how I would make sure I am doing what the Amp wants me to do?
    Also,I have always used Subs which have variable Hz controls & a volume control.Since mine is an Ht only system I set all the speakers to small and bypass the sub's crossover.In the past I have just used the sub's volume control to the level that sounded good to me.I had a Klipsch Ksw 12". I never calibrated the speakers or sub.Now I want get the most out of my Ultra so I have calibrated my new Pioneer 47tx using it's test tones with an Spl meter. I haven't been able to find an Avia Disc. All speakers are calibrated to 75 and the sub as near as I can tell is set about 78 dB.
    My other question is how does a volume control differ from a "input level control" that changes the Gain. The Samson manual"-80 means the signal is attenuated by 80 dB"(off)While turning the knob to 0 means the signal is at "unity gain"(that is no attenuation).How does this control differ from a volume control?
    Finally,I set the sub receiver volume level at -5dB(the lowest is -10 dB) The input(gain) control on the amp is set to 0dB.I have no idea if this is correct. The sub sounds good except for some localization.It seems while watching action shows on TV it is about correct. However while watching several test movies at about -10 thereis to much bass in certain bass intense parts.If I turn the gain down then there is not enough bass in other non bass intense parts of the movie. I know this is a matter of adjusting something but I'm not sure what.
    This is an awfully long question but if anyone has any thoughts I would appreciate it. Thank you.[​IMG]
     
  2. Brian Fellmeth

    Brian Fellmeth Supporting Actor

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    Regarding your first paragraph, consider the trick of placing the sub at the listening position then comparing how it sounds at the various candidate sub locations.

    Second and third paragraphs- sound to me like your in good shape with your calibration procedure.

    Paragraph 4- this is a type of volume control. The amp always runs full throttle. Volume control is acheived by variable attenuation of the line level input signal.

    Paragraph 5- might be that the crossover frequency in your pre-pro or receiver is too high. Many are fixed at 90 or above which is a crime unloess the sats are bass impared. If it is adjustable, set it at 50-60 Hz. Keep the sub's crossover disabled.
     
  3. GregLee

    GregLee Stunt Coordinator

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    I don't think you should be getting localization. It might be due to high frequency distortion products from the sub. In turn, that might be because the sub's volume/input level is adjusted too high.
     

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