Axiom Home Page Forums General Discussion Home Theater Calibrating subs & surrounds? What's the point?

Deep into my 4th week as owner of an axiom surround this system, I still have not calibrated my pb10 sub or my qs8s. Looks like I won't do it any time soon. Why?

I use my system mostly for music, and quite often for dd/dts concerts. But I noticed that different discs are mixed vastly differently and I find myself constantly adjusting to get to the sound I like. Case in point: Diana Krall's Live in Paris and Stevie Ray Vaughan's Live From Austin DVDs. The former has very strong bass and weak treble - setting the SVS at 9 o'clock gives me plenty of bass from John Clayton. In the latter, Tommy Shannon's bass is mostly MIA - dialing the SVS all the way to 3 o'clock helps, but not by much.

The Qs8s work great out of the box after some minor adjustment.

So what's the point of the fancy SPL and DVE and AVIA? Are they perhaps for HT, where the soundtrack mixing is much more consistent? I seriously doubt it.

Prove me wrong

I calibrated, but to an extent - particularly with music - I agree with you. Case in point, I was thoroughly enjoying the DVD-A of "Fragile" last night, sounded perfect. Then I put in "Chicago II" and the sub was out of control, unlistenably boomy and with a cutoff freq. way too high. Bad engineering of the mix? Possibly. But regardless, to listen to the album, I need to tweak. Same applies, to a lesser extent, to certain other albums.

I think many people end up turning their sub up and down depending upon the material and source...I know I do! There are some differences with the level of the sub channel from some SACDs or players I've heard. I don't fully understand it but find I'm adjusting all the time anyway!

I think it's still helpful to try to determine a standard. If the levels are all set on my electronics, I can "learn" over time to raise and lower by certain amounts with different sources.

Aw, hell. The guy's right! What are we bothering with this for anyway???

I think one of the reasons people tend to use different speaker settings (small/large, crossover frequency) with music vs. HT is that wide range of bass levels across recordings and the sub's ability to accurately reproduce even insane amounts of bass. This is just a guess, of course.

I find if I run my M60s in "large" and push the crossover frequency way down low (or even have the sub ignore mains LF) the apparent variation in bass level is much less and I can happily live without tweaking. If I run the normal HT setup (M60s to small, 80 hz crossover) when listening to music I find I often have too much or too little bass.

The M60s make all the bass I need for music, but the sub really adds a lot when playing movies. Just a thought.

I tend to agree, bridgman. I have my crossover set at 60 Hz; any higher and music just gets too sloppy fat in the low end. At 60, it hits some nice tones where needed, and the M60s pick up the rest and help keep the sound tight.

It's a little trickier with DVD-A's and SACDs, though, since the Denon 3910 has its own speaker/bass management for such output. While this allows for greater flexibility and is therefore preferable, it adds more variables into the mix. I cut the bass down for hi-res music generally; if I leave it at 0dB, it just buries the rest of the music.

This has done a lot to get it to where I don't have to do much tweaking album to album anymore, except in extreme cases (e.g. the aforementioned "Chicago II" DVD-A).

Before Calibration my subwoofer put out enough bass to kill a small baby. The waves seriously hurt my kidneys.. it was just so boomy and over powering... Now that it's calibrated it's nice and smooth and actually sounds like bass notes isntead of just the voice of god

Music was fine even before I calibrated, but after I find movies have a lot more clarity and the quality is just better.

Music is music, there's not much too it, but movies vary so much I've found it neccessary to calibrate.

Course I calibrated it and now I just play it... Only difference is subwoofer level on the receiver. for music it's +2.5, for movies it's -5.0 to -7.0

- D

I agree with Daphoid. Calibration is more heavily for movies. I believe, for the most part, that audio engineers adhear to the same sound mixing conduct because their variable is always the same. It's a big room with lots of seats and we want to play the sound at reference level.

So I would suggest calibrating for that reason. Then you'll have the sound mix the way the director intended...or close to it.

As far as music you'd probably still benefit, but I agree...bass can be all over the place for those mixes.

In reply to:

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So what's the point of the fancy SPL and DVE and AVIA? Are they perhaps for HT, where the soundtrack mixing is much more consistent?

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Speakers vary in their efficiency, even within the Axiom line. Powered subs have even more variation due to the adjustable volume.

While you can also go entirely "by ear", level calibration at least provides a starting point.

In theory with a calibrated system you hear what the mixing engineer intended. IOW if there's little surround it's because he mixed it that way. If there's a lot of bass or little bass it's because he mixed it that way.

With an uncalibrated system maybe you're hearing what the engineer intended, or maybe you're just hearing an artifact of the uncalibrated levels. You never know.

But as you said, there are WIDELY varying recorded levels, esp for bass. Also it does seem more variable for music than HT.

HT is more governed by standards like Digital Dolby, THX, etc. Music is often mixed in a more casual, artistic manner.

Some high res music formats had a turbulent development regarding bass management, and how multichannel should be supported or mixed.

Originally SACD was focused on two channel stereo only. When they finally adopted multichannel, the assumption was each speaker would be full range. Mixing standards and bass management was designed around that. At last the SACD community figured out most customers don't have 5 full range speakers, so began supporting (poorly) LFE/Bass out.

This results in wide variability in bass level across some recorded material.

Another source of variability is the age of original source material. Earlier material was often recorded and mixed assuming the end listener did not have good bass capability. If 95% of your audience is using portable transistor radios, why bother putting in content below 80 Hz?

That's one reason why older content varies so much. Many engineers took the above view. A few far sighted ones realized technology would improve and their music would eventually be played through better hardware, so made the investment in better mixing up front.

Current implementations require WAY too much tweaking, esp if you include the high-res analog input issues requiring double calibration for analog and digital sources.

There ideally should be a protocol developed and calibration info placed on each disc. Similar to the Digital Dolby "dialnorm" feature, except more sophisticated. The receiver could read that, plus read your calibration data from your amp, and adjust speaker/sub levels automatically to meet what the mixing engineer intended (which could vary from disc to disc). You'd have to do just one manual level calibration (none on auto-EQ amps) to provide the initial calibration data.

This would require a digital connection between the high res player and amp, some foresight, better mixing standardization, hardware/software protocols, none of which is currently happening.