"Official" Audyssey thread (FAQ in post #1) - Page 615

Hi,

It would appear that sometimes its better to ping the two subwoofers simultaneously and establish a single combined correction filter even if each subwoofer can be corrected individually. Below are Chris' remarks with regard to the SVS AS-EQ1 sub EQ, which is an add-on device designed to equalize two subwoofers.



So if your subwoofers are symetrically placed with respect to the primary listening location, having a single subwoofer output might not be an issue to be concerned about.

Larry

Hi Sanjay,

Thanks for the response.

Here's Dr. Toole's remarks regarding the standard:


(The accompaning layout drawing shows a shaded portion of the configuration between 60 and 150 degrees in which four or more surround speakers are permitted to be located. When more than two speakers per side are used it is suggested that they be distributed at equal intervals.)

It appears that the ITU is listening to you.

However, with such broad latitude by the mixers in placing their surrounds on the dubbing stage, it would seem there would be a much greater justification for the application of features such as DTS Speaker Re-mapping on home devices.

Larry

Hi Chris, all,

I got a new AVR-590 at Best Buy Friday to setup/check and then return, because I just wanted to see one that actually worked right and be totally certain that it wasn't something else specific to my setup (but what could it be?!). I wasn't sure what I was going to hear, and was afraid it wouldn't be right. But like it only took me a couple minutes to find that the refurb was messed up, I discovered almost as quickly that the lowest-end 590 works flawlessly with MultEQ as it should! I was gradual checking it. First made sure bitstream/PCM sounded the same with MultEQ Off (like the 1909s do), then MultEQ enabled (was like, "Wow, they're the same!"), then with Dynamic EQ ("Yep, for sure!!!"). Then later the graph of the output gave absolute evidence of what my ears already told me: bitstream/PCM actually remained the same with MultEQ in use.

You already know that bitstream/PCM sound/graph the same with MultEQ Off, so no need to post that again , but here's the other 2 for comparison with the refurb 1909. Note: I had to set the volume 8-9dB higher than both 1909s to get the same signal level on the graphs. Does that seem like a weird difference when they should be calibrated for reference level?? The 590's Audyssey set the speakers 4-5dB lower than any 1909 run, and the sub 10dB lower.

MultEQ On: PCM vs Bitstream (Plus the 2 MEQ Off measurements averaged and smoothed)


You said about the previous graph: "With some imagination, the pink curve can be shifted to the right and stretched to start looking like the red curve." Well I was thinking they actually looked more like flipped/mirror images of each other.

And the analog sweep for the sub this time:



Stuff sounds nicer than ever to me with the movie scenes I checked (even compared to PCM with the 1909s, which is pretty close to correct, but still a bit off, IMO). Maybe it's just my imagination, but I'd say less fatiguing/harsh. Another amazing part? I've left Dynamic EQ/Volume On with regular TV stuff, which generated too much rumbling back when I last tried it on the 1909. Now, not a bit (comparatively) -- probably some parts are getting boosted more than they should (mix problem) but never once have I thought, "Wow, that's annoying bass boom."

Why is that? Well, most of the channels I'd ever be on are HD ones, which of course only send out Dolby Digital, even if not 5.1, and what is that? A bitstream! Since the 1909s are screwing up bitstream decoding bigtime, I'd say that's the answer. And also every TV show I've seriously watched (all HD) since getting the 1909 has had its audio ruined!


After calling Customer Service again after they mentioned "setup issue," which was a complete was of time ("Can't think of a setting to check." "Don't really know of a setting that it would be." ), I replied to the e-mail again asking if they even reproduced the problem (didn't say), are they going to do anything to fix it, I shouldn't have to pay to ship it again for the same problem that they didn't even fix or bother to check the refurb for, etc. Response:

"I have asked our senior management to look at this. We will also be contacting Audyessy (sic) for further information.

I will get back to you as soon as I hear from them."

So I mentioned that the Audyssey Founder and CTO posts here and said it "is among the strangest issues I have come across." Also that you had already contacted Denon engineering in Japan and they couldn't reproduce my problem. Response:

"Our senior management will be contacting the engineering group in Japan to confirm or not confirm that this is a problem.

Just to clarify, we cannot rely on any forums for accurate information.

I will get back to you as soon as we hear from Japan."

Wow about the forums! I get what's meant I guess (disclaimer, etc.), but that sounds pretty stupid. So don't believe anything Chris or anyone else says here! I guess one thing that they're right with so far about Chris not being accurate is from the same post where you stated, "I think that only Denon can help you."

Amazing that a most basic/core feature seems like a dream to have working correctly at this point! I don't think Audyssey would be very pleased with MultEQ usage being broken if Denon doesn't care and/or continues to ignore the problem?

BTW, since I've had 2 problem units, I'm now confident that others are affected as well, probably unknown to the user, so I made a new thread: Warning for Denon owners: your xx09/x89 AVR may have a major bug. I'd love to know their results, especially correct ones. Do you guys have access to one of the 09 models, Chris? Or has one been used/checked/tested "personally" before...?

Since this is the Audyssey thread and your question appears to have nothing to do with Audyssey, perhaps you should post your question here:

http://www.avsforum.com/avs-vb/showthread.php?t=881446

That may not be the case across all manufacturers and models as my pre-DEQ/DV OP885 and MultEQ XT *does* setup with 75dB at measurement position #1 from all channels.

Jeff

Major point deduction for them, eh Chris?

Heh, maybe they're using a knockoff technology in mine: Audyessy MultiEQ.

Old school, monolithic companies used to having complete control with virtually no interaction among users loathe forums. New, progressive companies embrace and participate in forums using them as a means to communicate with their customers and potential customers. Denon and Audyssey would be two examples and I'll let you place them in the correct categories.

I remember seeing knock off Bulova watches that actually said "Bulovia" on the face and were sold with the minute hand over the "i."

Thanks Larry. Yes, the subs are symmetrically placed in the room but the room itself is not symmetrical. I'm not sure how much this effects the response of the individual subs as I don't have the equip. to measure it but I'd bet it would be significant.

It appears this special dual sub eq. is a feature of the SVS unit only and not part of the pre/pro and AVR's with dual sub capability. I wonder if this will ever be part of a pre/pro or if it will stay exclusive to the AS-EQ1 which although nice, seems a little on the pricey side.

Hi,

Hopefully Chris will chime in, but here's my take:

Being symmetrically located from the primary listening location takes care of the need for individualized timing adjustments.

When you do an individual correction that result is only really valid when only one subwoofer is playing at a time, but in the real world the two subwoofers will be playing the same signal and interacting with one another (i.e. constructive and destructive interference). So maybe a correction to the combined response is more appropriate.

The fact that the two subwoofer have different individual responses due to different acoustic environments might not mean as much around the primary listening location where the microphone measurements are clustered. Audyssey is going to correct for the composite affect of the subwoofers at multiple locations near the primary listener.

Just a thought.

Larry

The Dennon thread has come to a screeching halt.

Perhaps you need to relax and mind your own business. I am trying to get my system right and your input is not helping me. Now go wash the car or do something constructive.

while I agree with the other advice so far, I'm curious what type of content you notice the dialogue problem with? Were you watching a DVD or was this a movie on your cable box? There are sometimes horrendous mixes on cable channels, I have read many reports (and have experienced this myself) of DD 5.1 movies broadcast on some cable channels having super low dialogue levels.

if it's with a standard DVD or Blu-Ray which should have a good, properly mixed soundtrack, and you are still having dialogue issues after repositioning the center and re-running Audyssey, you should try out the Dynamic Volume feature (the Evening setting is great for this). It will allow you to set the volume at the point where you can understand the dialogue, and then it will prevent the other effects from getting so loud that they overwhelm everything.

BTW, Chris -- I didn't see this mentioned here but the cat is out of the bag and the Denon AVR-4810CI has been posted online.

I downloaded the manual and see this is the FIRST receiver which can not only do ANY of the 9.1 configs, but it can do a full 11.1 DSX setup with the addition of an external amp. Look likes it doesn't do individual sub EQ on the three SW outs, but no big deal as 11-channels is pretty freakin' cool (plus it's a moot point as I can't afford it anyway!) I will say that trying to understand the dizzying array of amp assign / config options made my Denon-to-English translationerator start overheating!

So, anyway, you are allowed to talk about it now. Congrats on finally having a product on the market that can unleash the full power of DSX!

so far it's only been on two blu-ray movies The Incredible Hulk and Pearl Harbor. then it's only when there are a lot of action going on also. i have the dynamic Eq on also.

once i get my new sub and get it set up i will re run audyssey and if i'm still having dialog issue i will try the dynamic volume.

gotcha -- that is not uncommon with contemporary action movies and their overwhelming surround mixes, especially on a tiny sub/sat setup like the Energy Takes. Those teeny little speakers don't really have the overall dynamics to cleanly handle huge action flick soundtracks at big volumes; I strongly recommend you try out Dynamic Volume on "Evening" mode, it kind of smoothes out the huge dynamic jumps while still retaining high quality sound.

i will try the dynamic volume next time i watch an action flick if i have problems with the next one i watch. i may have to look into getting a better center when i get my income tax money in next February. i'm pleased with the rear sound from the energy takes.

for now i did bump up the volume in the center by about 3db and that helped a lot.

Hi,

I missed your second question in my previous response.

As Chris mentioned in the certain AVR/prepros that have separate subwoofer connections, Audyssey will apply separate corrections to each subwoofer, (it will also do separate timing adjustments). I believe the big difference in function between such units and the AS-EQ1 is that the AS-EQ1 has its own dedicated DSP resources so it can offer higher resolution filters than AVR/prepros.

It is pure speculation on my part, but AVR/preopros have a lot of other non-Audyssey competing processing that imposes demands on the common DSP resources. So based on maintaining their price competitiveness it is not likely that they would incur extra costs just to add more resolution to Audyssey's subwoofer filters, which are pretty good to start with in comparison with other approaches.

Larry

EDIT:
Based on subsequent comments from Chris, I realize my posting was not precisely correct. Some AVR/prepros that have separate subwoofer connections can do separate timing adjustments. However, none of the current AVR/prepro models allow time and level alignment of the two subs prior to running MultEQ. That's currently only possible in the SVS AS-EQ1 and the Audyssey Sub Equalizer.

Not a good reply to someone who was giving you good advice.

I thought that audyssey was already taking care of the contractive-decostractive behaviour of two sub when measured individually.
I have dual subs, a Denon avp a1hd and audyssey pro.

Would like to hear Chris as well on this.
Can that be done with the AVP?

Also, it would be interesting to know what happens if I add the sub eq to the system, would Audyssey pro apply the extra 'unused' filters to the remaing speakers- since the subs would be taken care by a separate audyssey?
I am not even sure if it can be done, if yes, how?
Thanks

Hi,

Not exactly.

When Audyssey measures the subwoofers individually it builds filters to flatten the frequency response for each subwoofer. In doing this it does account for constructive and destructive interference caused by reflections off room boundaries. However, when another subwoofer plays the same signal at a different location, that causes another source of interactions which may be worse than reflections since they are not attenuated by bouncing off of room boundaries and acoustic treatments.

When taking individual measurements there isn't any constructive and destructive interference occurring from the other subwoofer for Audyssey to correct. It is only when both subwoofers are playing the test signal simultaneously that these subwoofer to subwoofer interactions occur, and only then can Audyssey attempt to correct for them.


So would I.

Larry

My channel level check is

Front L +1.0db
Center +2.0 db
Front R +1.0

Surround R +3.0
Surround L +0.5 db

Subwoofer -9.0 db

This is from a Denon 1910

I read that the maximum for sub is -+12.0 db.


Is this an acceptable range for my audissy setting for my sub or should I redo. It says to put the sub volume in the middle and start from there

The Dennon thread is dead. You might get a post every 8 days. I think I mentioned that already.

It might be good to turn down the gain on your sub a bit, and up the trim in the AVR, e.g., to ~ -5 or so, checking to keep the SPL the same as you now have.

No, if he is concerned about the sub trim, the proper procedure would be to turn down the knob on the sub and rerun Autosetup. This is why it is recommended to check the trims after just 1 position.

Johst, it's in the acceptable range unless you find you have boomy bass and want to trim it down at some point. As you don't have far to go at -9, I'd rerun as described above.

thanks for your response.

so, as I understand it now, if we were playing a mono signal thrugh all the speakers inthe system, even with audyssey engaged there could be some negative interactions between them, especially if full range speakers were involved, unless they were calibrated togheter as a one. But, don't notes overlap most the times even when multichannel is being played?

but I understand, that the lower range is more susceptible to this. Isn't it?

Hi,

Here's a more detailed explanation. Please refer to the attachment.

In this example there are two subwoofers placed symmetrically with the primary listening location centered on a couch. An off-axis listener is 13 feet from one subwoofer and 10 feet from the other subwoofer. This represents a 2.65ms delay between the signals coming from the subwoofers.

At 188 Hz the wavelength of the signal is such that the signals are 180 degrees out of phase, meaning they cancel each other, destructive interference. This causes a null in the combined subwoofer frequency response at the listener position at 188 Hz. Some subwoofers go this high.

Theoretically another 188 Hz higher the two signals are in phase and constructively interfere causing a peak in the frequency response. This pattern of nulls and peaks repeat every 377 Hz. I say theoretically because most subwoofers don't have any measurable output at 377 Hz so there are no further peaks or nulls in this case.

Just one big null at 188 Hz which isn't there to be corrected by Audyssey when only one subwoofer is measured at a time.


This situation will always occur for two subwoofers because they are always playing the same signal. It rarely occurs for all speakers, it might occur as a transient condition, but I doubt that would be a problem.

This occurs at all frequencies when there are two sources playing the same signal, or when reflections interfere with direct signals.

Larry

EDIT:
As a practical matter this is probably not a problem. I was merely trying to provide an explanation as to why Audyssey chose to default to a combined response measurement on the AS-EQ1 .

It's not worth arguing; if one would prefer to do what you say it is fine, though not necessary. A couple of dB down on the sub gain and up on the AVR trim will make no difference to the Audyssey result.

I have no idea what you're talking about so I wonder if in fact you have no idea what you're talking about. We are advising the fellow as to proper procedure to establish Audyssey reference EQ.

http://www.amazon.com/How-Win-Friend.../dp/0671723650