Axiom Home Page Forums General Discussion Technical Questions Sub calibration

Hi,

Just want to ask if my sub current settings is okay or not base on your experience. I am using onkyo 797 and SVS as sub.

My settings for Sub : receiver LFE level set to 0db for both DTS and DD

Receiver Sub volume level set to -8db
Sub Gain level set to half way or 12o'clock
Sub x'over freq set to max (40hz to 120hz range).

If I run a test tone on this setup, when it comes to sub test tone signal, my SPL needle is max out... I have to lower the receiver sub volume level up to -15db(lowest setting) and still I have to turn the Gain control of sub below just to achieve the same ratings on SPL to my other speakers....is this normal?

The normal procedure to calibrate your system is to set the receiver levels to 0bd (i will assume at this point that you already know about the reference level for the volume seting) run the test tone and adjust the sub gain to acheive the 75db on your meter. Your gain on the sub should end up being fairly low if you have it up around mid way point you will find that on higher bass levels the sub will clip as the gain is too sensitive.

Hope this helps

there are two settings on receiver, which one should I make 0db? the LFE level or the Sub Volume Level (speaker calibration settings). If I understand you correctly and assuming you are referring to the sub volume level, you want me to set the sub volume level to 0db and the sub gain to min and then slowly turn the gain knob to achieve the SPL 75db measurement, is this right? Well I actually tried this already, and if I can recall, the gain control only reaches one to two bars from the min(0) level. Is this normal?

This is from the SVS web site. Hope this helps.

"Make sure your receiver/processor master volume is set at "00 dB" or other easy to remember level, it will become your "reference level", one very close to that intended for home theaters by Dolby Labs. And finally, set your subwoofer amp’s volume control (if it has one) to at least half-way up to start. It’s a good idea to check the subwoofer level control of your receiver before you begin the test tones. Keep the receiver's subwoofer output control to about 25% up or lower than "0 dB" (or say -6dB given a typical receiver channel limits of –12 dB to +12 dB) . This will allow your amp to work with the cleanest signal possible from your receiver, while still leaving plenty of downward adjustment you can use from your viewing position (using the remote). As the tones start, alternating, speaker to speaker (watching your sound meter now) set each speaker’s volume to 75 dB, using the receiver’s channel controls. Not all test disks or receivers are the same when it comes to calibration tones however, the recommended Video Essentials should allow you to calibrate reference level at 75dB. Ovation's "Avia" DVD is recorded at a higher level to improve signal to noise ratios during calibration, so you need to measure instead to 85dB for all channels if you use it and not Video Essentials (discussion below, regarding a "boost" to your LFE still applies but you simply add the bump you want above and beyond 85dB, vice 75dB)."

wbwatts, thanks for the info, unfortunately I am new to this field and I'm having hard time understanding those technical terms...so If I understand this correctly..this is what I need to do (please correct me if I am wrong):

1. Set rcvr master volume to 0db.
2. Set my SVS sub Gain Control knob half-way 12o'clock position
3. what do you mean by this:

"It’s a good idea to check the subwoofer level control of your receiver before you begin the test tones. Keep the receiver's subwoofer output control to about 25% up or lower than "0 dB"(or say -6dB given a typical receiver channel limits of –12 dB to +12 dB)"

Does this mean, on my receiver speaker calibration menu, i set the sub level to 25% up (+3db) or lower than 0db (-6db)? at this point a test tone is already running on sub speaker...

4. Using SPL run a test tone an make sure the SPL reading reads 75db or 85db while adjusting the db level of each speaker?

So this means, I leave the Gain control on my SVS Sub to midway and adjust the db level on my receiver till it achieve 75 or 85 db? right?

Thanks

"So this means, I leave the Gain control on my SVS Sub to midway and adjust the db level on my receiver till it achieve 75 or 85 db? right?"


Seanandredj, here is how I set my SVS 25/31 pci:

The receiver volume is set to 00.
The receiver sub-level was set to -6.
Started with the sub gain mid-point (12 O’clock)

Run the test tones (use the receivers or one of the set up disks). Adjust the sub-gain to the desired reading. Mine ended up just shy of the 2 o'clock position at 85 db. I used the Sound and Vision set up disk.

This works for my sub. It's never distorted or bottomed out.
It will literaly shake the house when watching a movie such as LOTR and for music sometimes you don't know it's playing unless you turn it off.

Hope this helps.

That's interesting info from the SVS website considering this little snippet from the Axiom FAQ page:

"If it is necessary to turn the volume on your subwoofer above HALF to achieve the desired amount of bass, the amplified subwoofer system could be too small for your system. We would strongly recommend the use of the a bigger subwoofer in this case."

I'm hazarding a guess that the setup suggestions differ accordingly due to the different amps used for each subwoofer. or because of the fact that SVS recommends setting the LFE to -6dB prior to calibrating the gain. I recall the S&V disk recommends setting the LFE to 0dB before adjusting gain.

Chesseroo I have tried the various ways to set the sub up and to be honest I can't tell any difference. I think the main concern is getting it balanced with the other speakers.


FYI - Previously I calibrated the sub, setting the gain to mid point and adjusted the sub level to achieve ref. This resulted in a sub level of -4. Both methods sound the same to me.

Okay here's what Tom from SVS answered me:

"I would start out with the subwoofer volume knob at about 25%, and then adjust the receiver's built in leveler from there."

So that's less than mid-way....while wbwatts in your case you gain control is more than mid-way (2o'clock) right or counter clockwise??

Anyway I will try all the possibilities here and we'll see....I have to wait my neighboorhood living upstair to leave her apt before I start doing this (don't want a police came knocking on my door....) :-)

Seanandredj that's interesting info from SVS Tom and not even close to what their web site recommends.

It doesn't take that much time to calibrate so try it with the different settings. See if you can tell a difference and let us know.

Once you get it calibrated your main concern will be shaking your neighbor out of her upstairs apartment.

Sam, just a couple comments. As you've seen, even the manufacturer isn't in complete agreement on the relative settings for sub level on the receiver and on the sub. Whenever you get properly balanced so that the sub isn't drawing attention to itself, my thought is to have both controls at similar levels, not one high and one low. Another point: even better than setting the sub crossover at the 120hz max, since your SVS has a crossover bypass it should be used.