"Official" Audyssey thread (FAQ in post #1) - Page 1609

In a system like yours, the additional headroom gained by gain-matched is unnecessary. You're obviously not running out of headroom at your current listening levels. However, in a system that is more output-challenged, such as a system of dual F112's in a large room, the additional headroom can mean several dB of increased system output. In my dual F112 system, I was able to increase the levels from about -15 to about -10, which was pretty significant.

In your system, if you ever want higher playback levels, the higher set sub will be the limiting factor. You may never want those levels, but that doesn't change the fact that the one (set of) subs is working harder than the other (set of) subs. In fact the (set of) subs with the stronger input signal are using almost 4X the amplifier power and almost 4X the driver excursion.

The alternative is obviously, "gain-matching", which can still be done, even with Audyssey's scheme. I am using it in my system. I have gain-matched all 3 of my subs. I currently have the closest sub connected to Subwoofer1 and the further 2 subs connected to Subwoofer2. The closer sub was set by Audyssey at -9. The further 2 were set to -5. I split the difference and set both to -7. They are now all set to the same amplifier gain structure and they are all receiving the same input signal. IOW, they are gain-matched and still using Audyssey's EQ.

In terms of distance settings, the closest sub is set to an appropriate distance, (IIRC ~9 ft.), and the further 2 subs, (which are very close to being equidistant to the LP), are set to an appropriate distance, (IIRC ~13 ft.) I was able to tweak another dB or 2 out of them at the crossover by adjusting their distances, but it wasn't nearly as dramatic as when I had all 3 subs wired off of one output.

Craig

That may be true. However, I can absolutely state that this:



sounds a hell of a lot better than this:



Both are smoothed to 1/6th octave. Higher resolution measurements may show more information and more detail, but any measurement is better the *NO* measurement.

BTW,

One thing I forgot to mention... and I believe this is what you are refferring in terms of trim level...

After Audyssey runs... checking db levels, Audyssey sets all speakers to ~72db.
I set my SPL meter in MLP and I manually set speakers to 75db.

When it comes to the sub, I set it differently... Normally, I see Audyssey sets subs maybe +2 or +3, What ever the number I set both subs to -1 and then adjust the sub volume manually until I get 75db. When setting to 75db on sub... I take an average because when the pink noise is playing db level it is not constant so I try to get an average.

But you left out the part in blue...

it would seem like 1/12th octave is good enough to represent what we hear.

Just AAMOI, what SPL meter do you use and are you sure that it is more accurate than the Audyssey mic? SPL meters are notoriously useless for setting sub levels.

No question about that! And that is one of the reasons why the newer XTZ RA II Pro with 1/12th resolution is superior to the old one with only 1/6th.

I use Galaxy CM-140 for SPL meter. I think it's a decent meter. I wouldn't know how it compares to an Audyssey mic, but I would say much better than a Radio Shack SPL meter.

ARO is only a single EQ filter. It finds the largest peak and cuts it. If you are running ARO on each sub individually, you could be cutting peaks in the individual sub's response that don't exist in the combined subs response. Then, running Audyssey on the combined result, you are likely making Audyssey undo one or both of the ARO EQ's. The only way I would use ARO with Audyssey is if you can run ARO on both subs combined. That way, ARO will knock down the remaining largest peak before Audyssey.

Of course, the only way to run ARO on the combined subs is with the Master/Slave arrangement. If you are adamantly opposed to M/S, then I suggest you skip ARO.



It is the speaker level settings set by your receiver or pre/pro.


What were the subwoofer distance settings in the receiver or pre/pro?




Go into the menu and shut Audyssey EQ off. I don't remember what receiver or pre/pro you have, but I'm sure there is a menu setting for this.


Connect to the pre/pro and shut Audyssey off in the menu system. Use the test signals in REW to generate the FR curves. You may find my write up of the setup of my system helpful:
http://www.avsforum.com/avs-vb/showt...1#post19446901



Yes.


Be careful when re-setting the trim/levels in the pre/pro. You'll be changing the Reference Levels. This will affect Dynamic EQ, Dynamic Volume and the MVC Reference Level setting. If you don't care about any of those, then change them at your discretion. However, I suggest you maintain any offsets that Audyssey set. An SPL meter uses a different technique to measure the average levels than does Audyssey. Audyssey's method works better with Audyssey EQ. IOW, if Audyssey has set the CC to -5, and you want to raise it to -2, then add 3 to each of the other channels, no matter whether SPL of the other channels measures exactly 75 dB.

Craig

I respectfully disagree. I have used this strategy to optimize my own system and several others and it has always provided useful benefit. I won't disagree that higher resolution provides more info, but I'm not convinced it is *necessary* to optimize a system in a room.

Craig

OK... I'll be rechecking frequency with & with out ARO... but from previous testing I was getting better graph with Audyssey running with ARO than without... but I'll be rechecking.





That's what I thought


When I placed them in front I would say the actual distance... They way I had it before (one of them in front of an end table... I remember it set it to like12' when the actual distance was like 6'.



Yes, I'm sure there's a setting in my DHC-80.3... I'll be rechecking this.


Thanks for the link... I'll check it out.




hmm, interesting... Right now, I'm setting dynamic EQ to off for testing but may use it... So, I won't change the trim levels... and leave the db reference level to 72db instead of attempting to change to 75db.

That was true ... until Tron Legacy.

Wasn't Tron Legacy also recorded and mixed to SMPTE standards as well?

Two different things, really. FWIW, just about anybody can probably easily hear if a string on a guitar is 5 cents (5/100ths of the step from the note it's supposed to be to the one above or below) out of tune. Older stomp box guitar tuners are good for about 3 cents accuracy and nowadays even the cheaper ones are 1 cent accurate which can actually be a little annoying when you're trying to pull into acceptable tune in a hurry on stage but that's for another day.

So our pitch resolution isn't the issue. The issue is how we hear or don't hear FR anomalies in specific frequency bands. AFAIK, it depends on frequency and what's going on at the time, and overall we are less acute with "real" sounds than things like pink noise. It is generally said that narrow dips and peaks are less noticeable perhaps to the point of being sonically "invisible" even if they are fairly deep, while wider anomalies are audible sometimes at less than a dB. There's solid science on all this, just not in my head . . .

Hey Markus, care to share how you "wood" know how to set a EQ correctly based on the 1/48 smoothed data?

Now it's clear!

How about a little more "resolution" in your answer. I think I could figure out how to set up a parametric EQ based on the 1/6th octave smoothed response. What would you do differently with the extra resolution of the 1/48th octave information? With the unsmoothed curve?

Craig

Hmm. So what happens when the sound does not fall on the well-tempered scale? It's funny that a company that asserts that hundreds (thousands?) of control points are needed to adjust frequency response, but not when measuring.

I agree that the selectivity of the measurement does not have to be "infinite" but the way one decides it has nothing to do with the number of notes in an octave. This may be skillful misdirection so as to avoid telling us the actual details.

OK... So this time I move towers back to the floor and wanted to check the values placing subs in each corner. They are now sitting behind each table stand.

Subs cones are facing each other and are 90 degrees compared to front speakers.

I disabled ARO and set Phase to zero and here are the results.
1. Sub in corner by window. No EQ - Blue line
2. Sub in other corner (kitchen side). No EQ - Turqoise line
3. Dual subs no EQ - Red Line

I placed subs cones facing each other (90 degrees from front speakers)

After running Audyssey below are values:
R/C/L speakers set to 40Hz. Changed to 80Hz

Distances:
Left: 12.2'
C: 11.6'
R: 11.4'
SR: 4.2'
SL: 8.2'
Sub1: 5.8' (Actual ~ 2' from MLP)
Sub2: 10' (Actual ~ 8' from MLP)

Level Calibration (Trims)
L: -10db
C: -7db
R: -12db
SR: -12db
SL: -4db
Sub1: -3db
Sub2: -3db

Note: there's a null at crossover 80Hz... what should I do to fix ?

I think what Jeff meant was that the ridiculous amount of infrasonic content in some of the scenes in Tron: Legacy might have used up all his headroom and maybe bottomed his subs out. Perhaps the 'Entering The Grid' scene, or the scene where one of the programs screams 'De-Rez ME!' before jumping into some giant fan blades. The scene that immediately follows of Sam going down the elevator to get suited up also has some ULF.

I'd imagine he might have some problems with the 'Pod Emergence' scene in WOTW at Reference levels too as that scene is one of the prime candidates for ULF demos.

The bigger the room, the harder it is to reproduce the lowest frequencies at high SPL's and there seem to be quite a few more movies these days with ULF content than ever (something which was close to non-existent 10-15 years ago).

To play these scenes at Reference takes some seriously capable subs with quite a lot of amplifier power.

I couldn't watch any of those scenes at close to Reference levels without the subs bottoming out till I finally did what CraigJohn and many others have done and bit the bullet with Mark Seaton's Submersive HP subs (sealed sub with dual opposed 15" drivers and built-in 2400 watt amp). These subs are seriously capable down to very low frequencies. As shown in my graphs, down to 8Hz in my room.

My previous pair of Bag End Infrasubs could go flat down to 8Hz too, but not at anything much higher than 80db. If you look at the waterfalls in the 'Master Bass List' thread, some of the crazy bass scenes have content down to 3Hz and fairly high SPL's in the 7-10Hz region.

Watching the WOTW scene at Reference with a sub capable of plunging the depths is a ridiculous experience every HT nut should get to experience at least once (unfortunately, experience it once on someone else's system and you'll probably get hit by serious upgradeitis).

It's one of the reasons why the Train Crash scene in Super 8 was so disappointing. Lots of ear piercingly loud screeching, but no infrasonics to back it up. On a visceral level to me, the WOTW scene was much more effective at conveying the environment/atmosphere of the moment.


Max

BTW, I changed crossover in pre-pro to 100Hz and I have attached graph.

It appears that the null at 80Hz is not very extreme now.

Spike, what's your REW measurement setup? What equipment and how is it connected and mounted? You mentioned you're using a Galaxy SPL meter? Do you mount it on a tripod, boom mic stand?

When you run Audyssey, how many positions are you using? What is the mic mounted/placed on?

BTW, you might be maxing out the trims for your speakers (R and SR at -12db). And are you putting the Audyssey mic in the right couch seat for the 1st measurement? Your L distance is 12.2', SL is 8.2'. Your R is 11.4', SR is 4.2' Even though no one is sitting there, you might want to make the first measurement centered between the front speakers and make sure the Audyssey mic is no closer than 24" from the back wall.

The crossover region in your newest graph definitely looks better, but what I'm wondering, is why the regions below the crossover (below 60Hz) don't look the same vs the 80Hz crossover graph?


Max

Let's start with this. You are getting a lot more reinforcement from the corner kitchen side than corner window side. (Note the higher average levels at almost all frequencies in the turquoise line than the blue line.) That's not surprising because glass is basically transparent to bass and doesn't reflect bass frequencies well. The null around 60 Hz in the kitchen side sub carries through to the combined response. You also have a null at about 22 Hz that carries through to the combined response. More importantly, you're not getting any significant "room gain" at VLF's, (Very Low Frequencies), with either sub. Can you adjust the placement of the kitchen side sub to reduce the nulls and to try to improve the VLF's? Try moving it out of the corner to about 1/3 of the long dimension of the room.



The null at 80 - 85 Hz looks to be an interaction of the speakers and subs. Before you do anything here, try adjusting the sub placements as above. If you still have the null, since it is near the crossover frequency, you can try one of 2 things:

1. Change the distance setting of the subs. Change each of them the same amount. Start by raising the distances in 1 ft. increments. If you see an improvement, move in smaller 0.2' increments until you eliminate as much of the null as possible.

or:

2. Try moving the crossover down to 60 Hz. Then adjust the distance as above to see if you can eliminate the speakers/sub interaction and the room induced null with the distance adjustment.



Another thing you can do that will really help your response is to move your seating off the back wall. Sitting so close to the wall exacerbates the impact of the modes. Those nulls you see in the response may be a lot less prominent 3 or 4 ft forward of the back wall.

Craig

With REW, I use my laptop and connect CM-140 to it. Then I connect cable from laptop to pre-pro.

I mount the SPL flat on couch with no boom.

After Audyssey runs, it sets db levels at about 72db... Previously I would manually set all speakers to 75db... If I did this... trim would be less... but left it as is for now.

That works for the crossover point null, but it doesn't do anything for the 60 Hz null. Try lowering it to 60 Hz and see what happens.

Another thing you can try is to adjust the ELF Trims on the JL's to +3. That should give you some more low frequency augmentation. However, it'll use some system headroom.

Craig