Subwoofer set up question

Discussion in 'Audio Hardware' started by Fruff76, Sep 6, 2019.

  1. Fruff76

    Fruff76 L100 Classic - Fan Club President Thread Starter

    Location:
    Pittsburgh
    I’m trying out an SVS with my L100’s to see what it does for the frequencies below 40k only. I don’t want it interfering with anything above that and possibly altering the sound. So I have it hooked up the the “pre out” on my NAD, which has a filter at 40,60,80 and 100Hz. I have it set up at 40. Maybe I’m not quite understanding this, but shouldn’t there be no sound or movement from the SVS if there is a cutoff at 40? When I turn the volume up, it’s clearly putting out sound. The way I figure it, I should be able to turn the volume all the way up, and as long as there is no signal below 40HZ, it should still be quiet. Is this correct.
     
  2. Mike-48

    Mike-48 Forum Resident

    Location:
    Portland, Oregon
    Crossovers are more gradual than that. A first-order crossover attenuates at 6 dB/octave, which means that with a 40 Hz crossover frequency, the signal would be down only 12 dB at 160 Hz. If it's a second-order crossover, it would be down 12 dB at 80 Hz, 24 dB at 160 Hz.
     
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  3. Fruff76

    Fruff76 L100 Classic - Fan Club President Thread Starter

    Location:
    Pittsburgh
    I don’t hear much that enhances my system with it. When I turn it up, it interferes. When I turn it down, it doesn’t seem to do anything.
     
  4. F1nut

    F1nut Forum Resident

    Location:
    The Mars Hotel
    Your speakers are rated at 40Hz-40kHz (-6dB), which means you need to set your filter higher, at least 60Hz.

    Which SVS sub do you have?
     
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  5. Fruff76

    Fruff76 L100 Classic - Fan Club President Thread Starter

    Location:
    Pittsburgh
    The Sb 3000. I’ll try 60.
     
  6. The Pinhead

    The Pinhead SLEAZY SOUTHAMERICAN CAVEMAN

    There ain't much signal below 40 hz man. B-strings on 5-strings or detuned bass guitars, lowest notes of pipe organs and synths, and not much else. The rest are quiet lower harmonics of higher notes. My speakers respond down to 39 and I can't cross the sub under 65 if I want any low-end reinforcement at all, so it's at 65, but it remains unused during half of my records.
     
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  7. Mike-48

    Mike-48 Forum Resident

    Location:
    Portland, Oregon
    Indeed. You might find this chart interesting:

    [​IMG]

    And besides trying different crossover frequencies, you might try moving the sub to different locations in the room to see where it blends and sounds best.
     
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  8. Catcher10

    Catcher10 I like records, and Prog...duh

    I just got a SB2000 connected to my Parasound HINT, which has a nice crossover system I have the HINT low pass set at about 60Hz, My Rega RX5 freq spec are not published but based on the 7" side firing woofer and port I have measured around 35Hz. SVS suggests setting crossover at 15-20Hz above the low end of your L/R speakers. Its not a hard crossover, there is some overlap which is better, but not too much.
    With your speakers I would start at 80Hz and listen for a few days.......Don't forget the SVS volume knob, find the best level so you don't notice the sub when its active.

    My sub stays 100% active when I am playing records and my R2R deck. It goes in and out when I play my digital files, makes some sense as digital is cut off at 20Hz. The Delos is rated at 10Hz, the Parasound at 10Hz -3dB so I suspect I retrieve more low freq thru my analog setup.

    Bottomline the SB2000 has added a whole new dimension to my music now.
     
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  9. Fruff76

    Fruff76 L100 Classic - Fan Club President Thread Starter

    Location:
    Pittsburgh
    Changed the setting on my pre out to 60hz. It’s definitely blending well now.
     
  10. Fruff76

    Fruff76 L100 Classic - Fan Club President Thread Starter

    Location:
    Pittsburgh
    What is your volume set at?
     
  11. Catcher10

    Catcher10 I like records, and Prog...duh

    Straight up 12 o'clock......phase should be at 0 also.
     
  12. Fruff76

    Fruff76 L100 Classic - Fan Club President Thread Starter

    Location:
    Pittsburgh
    Mine is behind my chair, should it be 180?
     
  13. Catcher10

    Catcher10 I like records, and Prog...duh

    SVS has amazing phone service, they will help you get your settings right, you can call them anytime. I think they are open on Sat till about 5pm est.
     
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  14. Fruff76

    Fruff76 L100 Classic - Fan Club President Thread Starter

    Location:
    Pittsburgh
    Thanks, I think it’s a keeper.
     
  15. Catcher10

    Catcher10 I like records, and Prog...duh

    I don't think so, since you only have one sub. SVS told me the phase is more important when you have two subs and in opposite corners to offset the separation of the subs.
     
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  16. F1nut

    F1nut Forum Resident

    Location:
    The Mars Hotel
    Great. Don't be afraid to keep tweaking. Setting up a sub to blend seamlessly takes more work than most realize.
     
  17. avanti1960

    avanti1960 Forum Resident

    Location:
    Chicago metro, USA
    forget the pre out filter- turn it off and let the sub crossover do the work it was designed to do- much finer control and the proper slope for the sub. two filters in series is not a good way to go.
     
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  18. BIGGER Dave

    BIGGER Dave Forum Resident

    Agreed. When I added an SB2000 to my Harbeth M30.1, I used the SVS “Chat” function to get the optimal settings for crossover and phase. The settings the SVS rep suggested were spot-on!
     
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  19. Think of the sub like an as-needed helper trying to interact with your main speakers.
    As the main speakers begin to roll off in the lower frequencies you want the sub to begin taking over...helping just enough at first, rather than being a light switch and taking over fully.

    If the sub is set at the wrong frequency (too high or too low) it will barge in and be noticeable.
    If too high the sub may seem forward, boomy, and in your face.
    If too low there will be a lag, or loss of low frequencies, between the main speaker roll off and the sub really coming in.
    In either situation the sub will be very noticeable both in sound and placement..as in, I hear the sub now, and it is right over there.

    When you have the crossover set to blend with your main speakers, as well as work best in your room (placement is part of this equation) the sub should basically disappear with the sound going to the low frequency limits of the source and equipment...seamless low frequencies coming from the room, rather than the sub in the corner.

    Sometimes, as in my situation, you are stuck with less than ideal placement of the sub. In these instances you will have areas in the room with higher or lower dB and you just have to live with that. Tune that as best you can and move on.

    Look at your speakers design parameters and set the sub cross over about 20 Hz- 30Hz above the low frequency limit.
    This will allow the sub to come in gradually as the main speakers roll off.
    Play with the Hz setting, as well as the sub volume and soon you will find the spot...This is when that uncontrollable grin may land upon your face because you finally realize there really is no apparent sub, just full low frequency sound everywhere.
     
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  20. avanti1960

    avanti1960 Forum Resident

    Location:
    Chicago metro, USA
    right you are- and unfortunately you adjust for quite a while as the sub continues to break in and its sound + output changes. (for me it was almost continuous for a year and a half)
     
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  21. Mike-48

    Mike-48 Forum Resident

    Location:
    Portland, Oregon
    If the SVS has an app to help set phase, use that. If not, I'd start at 180, since the sub is behind you. The optimal phase setting is the one giving smoothest response around the crossover frequency.

    How do you find that? Easiest is to measure. To do it by ear, sit in the listening chair and, using a test tone at the crossover frequency, adjust phase for maximum output. An equivalent some find easier to hear is to reverse the main speakers' leads (so the mains are in reverse phase) and adjust the sub phase for deepest null at the crossover frequency -- then of course switch the mains back.

    I agree with @F1nut and @avanti1960 the getting the best from a sub can require a lot of tweaking over time.
     
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  22. Catcher10

    Catcher10 I like records, and Prog...duh

    This is spot on, ideally you want to use crossover at the amp, but in your case I would do this. Use the SVS crossover and don't use both, that causes imbalances.........If you do leave the crossover at the amp then make sure the SVS crossover is set at its highest or to LFE.
     
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  23. Fruff76

    Fruff76 L100 Classic - Fan Club President Thread Starter

    Location:
    Pittsburgh
    I have to say, after having this SB-3000 for a few weeks, it’s pretty awesome. It’s not always needed with my JBL’s, but for that stuff with extreme low frequencies, it’s very impressive.
     
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  24. Catcher10

    Catcher10 I like records, and Prog...duh

    Agree, my SB2000 is starting to break in nicely and even though I am still fiddling with it, it has added a new dimension to my music. It's strange as I actually feel it is helping my main speakers be more dynamic and exude more resolution, yesterday I was listening to a very familiar pc and I was hearing bits I had not noticed in the past, and not in the lower range. Does taking some of the low frequency away from the main speakers allow it to focus on mid/upper ranges better/more??

    Maybe I am just coo-coo for cocoa puffs.........regardless I am hearing more detail and resolution.
     
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  25. Manimal

    Manimal Forum Resident

    Location:
    Southern US
    Try 80hz and move down .
     

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