Room correction setup guide for ML’s

[Waboman]

I decided to redo my Audyssey the other night. Why? I guess I'm a glutton for punishment. It's never the same, no matter how many times I run it.

Two things that are sticking in my craw. This time Audyssey set my center channel at +0.5db down from it's previous setting of +4.0db. Also, both my subs were lowered from Audysseys' previous setting to -11.0db and -10.5db. Down from -10.5db and -9.0 respectively. What's bizarre is, I seem to be getting more LFE now. Almost too much (if there's such a thing). I busted out my trusty SPL meter and with the exception of one channel every other channel is below 75db. Not a big deal, as I'm sure room refections were a big reason why. However, I did bump my center back to +4.0db.

Why the big increase in LFE at lower settings? And why such a drastic decrease at my center channel?

Previous Audyssey settings:



Latest Audyssey settings:

[Waboman]

Well, I ran another Audyssey and the inconsistencies continue. This time it put my sub levels back to where they were previously. But it raised both L&R speakers considerably. I have noticed how much more aggressive my subs are even when placed back down to their respected levels. Not sure what's going on here. But simply watching the Food Network there was way too much LFE.

Just while running this current cal, I noticed how much more aggressive my subs were than the rest of my speakers

So, for even more torture, I unplugged the subs, then I will plug 'em back in and run another Audyssey. Yep, two cals in one night.

New speaker levels. The inconsistency baffles me.

[JonFo]

...
After serveral runs I find that following the advice to sample different heights to get the vantage right seems to take the microphone out of the sweet spot for the cinema I
If the trim setting comes from my first measurement then my putting the mic 10" from the back of the sofa brings the tip of the mic out of the sweat spot which is where our ears our closer to the back of the sofa.

Any suggestions for a Audyssey calibration that would get the center speaker trim correct?

Thanks for your advice.

Sounds like the pattern you are using places the mic well outside the coverage area of the center speaker, which leads to a large boost in level (and probably some pretty serious boosts in mid-frequencies as well).

This is because the ML centers have a narrow vertical dispersion on their mid-range coverage due to a very short panel height. One reason they added the dynamic tweeter is give better vertical (and horizontal) coverage to the center.

So if during measurements you take readings too close to the speaker, the mic will be below the coverage. Likewise, being too far back and too high will move the mic above the beam from the panel.

The trick is to find the best compromise of locations where ALL beams overlap and keep the mic within those.

The problem with a high-mounted center is that the beam intersection with the mains will be relatively small. That’s not too big a deal, just measure inside that area.

Better to have corrected for that smaller footprint, than have inappropriate EQ applied and overboost the sound for the sweet spot.

[JonFo]

...

Why the big increase in LFE at lower settings? And why such a drastic decrease at my center channel?

Yep, frustrating that this process is not as repeatable as one would like, but I can tell you, very small changes in mic positions make significant changes in impulse response measurements.

Unless you've played with acoustic measurements a lot (>100hrs worth), it's hard to comprehend just how complex sound-fields really are, and how tricky measurements can be.

So, why did you get better LFE?

Possibly measured a more uniform pattern that caught more room modes, or the spacing clustered the measurements differently and the algorithm decided to correct with fewer LF cuts.

The decrease in the Center is likely related to what I outlined in my response above. Your latest measurements probably caught more of the center channel in the prime beam covered by the centers panel. A good thing I'd say.

However, I understand why you turn it up a little, as any seat outside the prime location(s) where the center panel and L/R speaker panel beams intersect will have too low a volume.

Sort of why I wound up building my own center

[Gordon Gray]

Hi Waboman,

If you keep running the calibration and it continues to give you different results, why do you continue to do it?

Ever tried tuning just trusting your ears?

GG

[jmschnur]

Thanks for this. I thought I had been correcting the height. How limited is the horizontal dispersion?


How far left and right of the center of can I go.


I assume I can only use the center aiming point for the vertical dispersion now. I had been putting a laser on top and bottom of the speaker and just putting the mic between those the top and bottom of the speaker and then placing the mic between the edges defined by the lasers. I will now go for the exact center.


How much better is the stage than the cinema I with respect to these issues?

[JonFo]

Thanks for this. I thought I had been correcting the height. How limited is the horizontal dispersion?

For vertical, dispersion is very tight. Only the height of the panel, so about a foot. Not kidding.

For Horizontal, it's better, with a roughly 30 degree spread.
But I find the coverage at the edges of that is marginal, so try and get the seats within a 25 degree angle.

How far left and right of the center of can I go.


I assume I can only use the center aiming point for the vertical dispersion now. I had been putting a laser on top and bottom of the speaker and just putting the mic between those the top and bottom of the speaker and then placing the mic between the edges defined by the lasers. I will now go for the exact center.

Correct, and intersecting the center channel coverage as well.
Within that set, do vary mic height a bit, but it's all about figuring the correct measurement 'bubble' for your setup.

How much better is the stage than the cinema I with respect to these issues?

The Stage is a much better speaker, but still suffers from limited vertical coverage. Only a solution like my SL3XC or a third unit of whatever model you use for L/R will really address that problem.
I hate to say it, but unless you've heard a 48" tall (or bigger) center channel panel, you've not really heard multichannel ESL magic.

[jmschnur]

Sounds like the pattern you are using places the mic well outside the coverage area of the center speaker, which leads to a large boost in level (and probably some pretty serious boosts in mid-frequencies as well).

This is because the ML centers have a narrow vertical dispersion on their mid-range coverage due to a very short panel height. One reason they added the dynamic tweeter is give better vertical (and horizontal) coverage to the center.

So if during measurements you take readings too close to the speaker, the mic will be below the coverage. Likewise, being too far back and too high will move the mic above the beam from the panel.

The trick is to find the best compromise of locations where ALL beams overlap and keep the mic within those.

The problem with a high-mounted center is that the beam intersection with the mains will be relatively small. That’s not too big a deal, just measure inside that area.



Better to have corrected for that smaller footprint, than have inappropriate EQ applied and overboost the sound for the sweet spot.

Thank you very much for your advice- it has been very helpful.
Since I do not have a projection system, the tower center concept which looks great by the way, will not work for me. I will persist with the cinema i for a while and redo very carefully my calibrations.

Once I have that down- I may go for the stage. I have head ML is putting out a new center speaker in about 12-18 months. Any chance that will have wider vertical dispersion?

Joel

[jmschnur]

Another question:

Is the jim powers flashlight alignment tweak appropriate for use in an Audessey calibration?

[JonFo]

The 'flashlight' alignment technique is OK to follow for speaker setup.
It primarily is geared to ensure your rear-wave is not directly bouncing back into the panel, which really destroys imaging and sound quality.

[jmschnur]

Thanks for the insights !

[jmschnur]

I am integrating an Jl112 and a Descent i into my system which has l/r vantages and a center Stage.
The surrounds are NHT diploes frm another era and the rear backs are nht ceilings also from the 90's.
I am using the audyssey pro kit.

The Descent i manual says to set the phase to 90 for that sub with ML panels
The audyssey guide says use 0 as the setting prior to the caibration.

So what is best for me to do iwth thie 7.2 system. The descent is behind one of my Vantages. the JL112 is on a side wall.

[JonFo]

jmschnur - Set the phase at 0 on the Descent (and the JL). Audyssey will adjust for any sub to Vantage phase / delay match.

If you have the option, look at placing one sub in center front, and one sub center rear. But center font, and 1/3 back from front along side wall also works well.

[jmschnur]

Thanks very helpful.

[jaandmel]

Hello JonFo,

I have new Electromotions and a Feature center channel. While I absolutely love what Audyssey does for the bass in my room, I am not so sure about the mids and highs. With Audyssey engaged they seem to lose a little of the air and sparkle that I love so much with the stats. Is this because of the mid-range compensation and rolled off highs that Audyssey applies? Thanks,

Jason