Need help new SVS sub and calibration

Discussion in 'Archived Threads 2001-2004' started by Sean_B, Sep 20, 2002.

  1. Sean_B

    Sean_B Stunt Coordinator

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    I just received my subwoofer yesterday. The 20-39 PCI model. It is so big it looks like a water heater. It sounds pretty good but know it would be better if properly calibrated. All my speakers are calibrated throuh AVIA but when it comes to sub calibration I'm at a total loss on how to do it.

    The very first thing is the left-main/subwoofer. I'm able to get these two about the same db level through the SPL meter (albeit when the sub is heard it jumps a little above and below where the left main speaker is). Then when you move on to the center channel and right speaker the sub level is significantly lower than those channels. So my question is this. When you adjust the sub for those channels you change it for the one you previously did. So I am very confused. I wish there was just one sound test tone out of the sub instead of all this other stuff I don't feel necessary. My receiver doesn't have a test tone for the sub and besides that I wouldn't trust it anyways as AVIA test tones were way different than the receivers.

    Please shed some light on this subject. I have done forum searches but I haven't found my answer. I am not the most technical person so guide me through this process like a baby.
     
  2. Sean_B

    Sean_B Stunt Coordinator

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    bump
     
  3. Doug BW

    Doug BW Stunt Coordinator

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    Sean, congrats on your subwoofer purchase. I think you're doing pretty much the right thing in the way you're calibrating.

    Here's my theory as to why you're getting inconsistent results.

    First, you need to understand how Avia generates the test tones. It does not generate tones in the ".1" LFE channel (at least not the tones you were using). Instead, it generates the tone in one of the main channels and lets your receiver's bass management redirect the bass to the sub.

    For example, with the "left-main/subwoofer" test, it alternates between generating higher pitched pink noise in the left channel and lower pitched pink noise also in the left channel. Your receiver's bass management splits the lower pitched pink noise between your left speaker and your sub. Similarly with your center speaker, etc.

    So, when you measure the SPLs with your meter, you're not just measuring sound coming from your sub, but also sound coming from one of your main speakers.

    Not all your main speakers will generate their "share" of the bass equally loudly. I know you already calibrated your main speakers...but that calibration was done using higher pitched pink noise, so the relative capability of your main speakers to generate bass was not taken into account then.

    You might even find that your left and right speakers (which are identical to each other) generate bass at different levels. This may be because they are positioned differently in your room and one speaker may be more optimally placed for bass than the other.

    Try setting all your main speakers to "large" and running the Avia tests. This will take your sub out of the equation altogether. See if the bass test tones measure the same for all your main speakers. This will tell you whether or not your main speakers all pull their weight equally when it comes to bass. (Don't forget to reset your speakers to "small" when you're done.)

    Like I said, just a theory....
     
  4. SVS-Ron

    SVS-Ron Screenwriter

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    Sean,

    I assume you meant a very svelte, high-tech, SEXY looking water heater right? I'll let that slide ;^)

    What you have run into is the one reason I sometimes shy from Avia for new folks. It's a GREAT disk (we say as much on our own website), but for simple, accurate and quick speaker calibration (especially for the sub) you might want to try Video Essentials. The old version is a bit dated but I can show a newbie how to calibrate dead on spec with a sound meter in 5 min., tops.

    VE has simple tones, one for each channel, and one for the sub, each in turn. Piece of cake.

    If you have access to VE, borrow it and hit the calibration tones (it can take some time to find them in the clunky menus) for a no-fail calibration you can understand and tweak with ease.

    Ron
     
  5. Bill Kane

    Bill Kane Screenwriter

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    Avia says in the Introduction (text) to Swfr Set-up that test tones are provided for center, Rt Main and Surround only for the "rare" cases in which the sub is connected to more than one channel. 99 percent of us use the regular method of sub hookup and we try to have matching speakers (same series) to retain tonal quality or timbre.
    The Avia text declares that in the latter case, the majority of users, all you need to do is match the sub to the Left Main in the test. Finite. You're done. So forget about trying to match the sub all around.
    Once you've matched the sub level to the mains -- 75dB or 85dB, your choice -- you then have a known balanace and you are free to use the receiver remote to adjust the SWFR level up or down as much as yopu want for different sources of playback. Be careful, as much as +10dB over for DVDs, you risk overloading your sub. At the most, I've seen +4dB "hot" recommended by SVS-Ron for DVD listening playback. CDs and tv broadcast bass levels depend on your preferences.
    bill
     
  6. Sean_B

    Sean_B Stunt Coordinator

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    Ron: I was just lucky the fiance accepted it! She is the one that told me it looked like a water heater.

    Bill: That is a load off my mind setting it just to the left main speaker. But my next question is, why would it be the left main and not the right main? What makes the left speaker the one to guage it with? I want to believe this so it makes setting it up a snap but I'm having a hard time convincing myself.

    So when you say -4db hot then with AVIA you are saying that the SPL should read around -89db? I am under the impression that the SVS gain knob should be set higher rather than the receiver gain. My receiver's number of 0 db is at its loudest. -20 db is its lowest. Should I start at -20 and then work my way up the best way?

    SOrry for all the questions guys, i appreciate the input!
     
  7. Bill Kane

    Bill Kane Screenwriter

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    Sean,

    The rcvr/sub balance problem HAS been covered in many posts, but I'll give it a shot. Rcvr SWFR Level gain and Sub Amp gain are two separate controls that interplay differently among different rcvrs and sub amps. No direct correlation.

    [Personal Rant: I wish people wud specify make/model of the gear in posting questions sted of 'my receiver'. Rant OFF]

    I have an SVS sub. I have a rcvr with SWFR level -20 to 0dB.
    I call it a "two-handed exercize" in setting the Sub Amp gain control AND the rcvr's SWFR level.

    SWFR level output to SUB OUT is a low-level voltage control. You dont want it at max 0dB because there's no room to adjust UP. You don't want it -20dB because it might not send enough voltage to keep the Sub Amp "Auto On" feature energized. So we look for a golden mean.

    Set the rcvr's SWFR Level in the lower third of the scale, say -12dB. When playing the Left Main pink noise tone, adjust the Sub Amp control up until you reach 85dB on the meter. With luck, with the great SVS amp, this gets you somewhere in the midpoint of the sub amp scale. SVS-Tom recommends this "midpoint" method. I believe the Sub Amp control should be "set it and forget it."

    Why start with the Left Main? That's where AVIA starts the rotation. Also, some rcvrs are designed to adjust the overall VOLUME control to find the reference level. This may end up -17.0dB for 85dB as mine does. To balance my Right Main on MY rcvr I have to use the L/R Balance setting in my Speaker Set-Up menu. Other makers use a system that starts by setting the rcvr to 0dB. Often these rcvrs have volume scales that extend to +10dB.

    If you set your SVS "hot" just listen for awhile under different sources. I find that I'm always boosting in more or less depending on what's playing: DVDs, CDs, cabletv broadcast or FM. That's my preference.

    There is debate whether RS SPL is accurate for our everyday setting as it reads on the meter. Others suggest the RS meter actually reads 2-4dB LOW when it says 85dB when setting the Sub and actually is outputting 87-89dB without setting it even more "hot" Your room ought to tell you what you're liking. SVS says their subs smoothly blend the bass and sound more gentle than typically "boosted mode" people start out with. That's why it's said to calibrate the sub to 85dB at the outset and try to live with this a few weeks. The sub really shouldn't call attention to itself in the room.

    Dont feel "sorry" to ask questions, that's what the forum is for, and you'll often get responses that prompt you to come back for clarification!

    bill
     
  8. Sean_B

    Sean_B Stunt Coordinator

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    'My Receiver' is a Yammy 995.

    I calibrated the sub at -85db and then further set it hot a few db's. While playing a DVD I was very disappointed with the bass output. It no longer had the punch that I was getting with the sub uncalibrated. At calibrated level the gain knob on the sub was halfway between the halfway point and 3/4 point. The receiver was set at -12db. I wasn't happy with the output of the sub until I cranked the gain knob on the sub up to the 3/4 point whilst leaving the receiver's setting at -12db. When I used the SPL meter on the sub the needle went way past where it should be (the meter only goes up to 90db) and don't know exactly what the sub's db level is. But this sound was my preference for DVD movies. I think a lot of it has to do with my room acoustics. It is a very big and open room. So I probably have to overcompensate. Now music is a different story, I have to turn the bass down to the calibrated level because I prefer not as much bass in music.
     
  9. Bill Kane

    Bill Kane Screenwriter

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    Sean,

    ...yeah, you'll be dialing in your preference.

    However, I suggest that you leave the Sub Amp at the original position of "between mid and 3/4" and just use the Yammie remote for convenience, sitting in your chair. You'll soon learn how many dBs settings you like away from the "reference" of -12dB, up or down. Thing is, now you'll have that range convenience without having to get up and change the sub amp setting all the time.

    bill
     
  10. JohnDG

    JohnDG Stunt Coordinator

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