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#1 ·

I've been in several threads lately where the topic has been all about Audyssey and I've noted that there's not actually a thread specifically for it. There's one that seems to be about it, but it's titled as being about the Denon 3806. Audyssey, of course, exists in far more receivers than the 3806 nowadays, so I thought I'd throw a starter into the pool to see if people were interested in having one thread to discuss all Audyssey issues/comments/questions/stories/impressions that they've come up with from their personal receiver-experiences.


Myself, i was quite anti-Audyssey when I first came across it. My ears were quite used to what they'd had before which was very bass & treble heavy. Time has passed and I've really come to understand the strengths of Audyssey and respect the clean, flat signal that I now love and enjoy (and couldn't imagine being without). I'd love to hear from anyone else that wants to chime in or discuss issues.


Basic starter-links:


The Audyssey homepage .


The types of Audyssey implimentations in different receivers.



The Audyssey FAQ


The Audyssey setup guide


====

Audyssey tips:

Microphone Placement


The microphone has been calibrated for grazing incidence and so it must point to the ceiling during calibration. Any other orientation will produce incorrect results.


The microphone response has been calibrated to match (on average) the response of an industry-standard ¼ instrumentation microphone. It is critical to use the microphone that came with the receiver and not one from another model that may have a different calibration curve.


It is also important to place the microphone on a tripod or other stand so that it is at ear height. We strongly recommend against holding the microphone in your hand because this can give rise to low frequency handling noise that will cause the MultEQ filters to compensate by cutting those frequencies. Furthermore, it is not recommended to place the microphone on the back of the couch or recliner. If a tripod is used, care must be taken to ensure that the microphone is placed at a height just above the seat back so that reflections from the seat do not cause problems at higher frequencies.


The first microphone position is used to calculate the distances to each loudspeaker and subwoofer and set the delays. It is also used to measure and set the trims. So, it is important to place the microphone in the main listening seat for the first measurement.


MultEQ measures the background noise level in the room before playing the test signal from each speaker. For the measurements to be valid, the signal to noise ratio must be above a certain threshold. If it is not, the test signal from that speaker will repeat at a higher level. If the noise in the room happens to be higher during some of the speaker measurements, then the test signals from those speakers will sound louder than the test signals from the other speakers. This does not affect the calculation of trim levels. If the room noise is too high even after the test signals increase in level, then an error message will be displayed warning the user that measurements can not be completed.


After the first position is measured, MultEQ measures other positions in the room around the listening area. These do not necessarily have to be in each individual seat. The idea is to capture as many points around the listening area as possible so that the acoustical problems that affect the quality of sound within that area are minimized.


For example, we recommend taking 3 positions on the couch facing the TV and then 3 more positions about 3 feet in front of the couch and parallel to the first three. Measurements up against the back or side walls should be avoided.


Some loudspeakers have rather problematic responses when measured off-axis (i.e. more than 15° away from the imaginary straight line that points to the listening position). In these systems, measurements taken too far away from the center line will show a reduced high-frequency response that may result in overcorrection and thus overly bright sound. Although it is difficult to predict which type of loudspeaker will have these off-axis problems we have most often observed them in poorly-designed multiple-driver arrays that exhibit very high off-axis lobing. In these situations we recommend a tighter calibration pattern centered around the main listening position and making sure that the mic is not placed in extreme locations and certainly not outside the plane of the front main speakers.

Checking the Results


Once MultEQ calibration is complete the results are stored in the receiver memory.


It is important to activate MultEQ by selecting one of the target curves. This is not performed by default after the calibration is finished and must be selected by the user. In a THX system we recommend using the Flat setting that allows the re-equalization to work as intended. In other systems, we recommend Audyssey for movie playback and Flat for music playback. Unfortunately, the music industry does not have any mixing standards like the movie industry so some music program material may sound better with the Audyssey setting. Front Align also uses the Audyssey process, but it does not apply the filters to the two front loudspeakers. Manual is not an Audyssey setting and does not use MultEQ filters. It is a simple parametric equalizer and will be subject to all the limitations that come with parametric EQ.


Small vs. Large speakers. This is the most commonly discussed topic by MultEQ users. The first thing to understand is that it is not a personal insult to your system if your speakers were detected as Small. It simply means, that in the room they were measured the - 3 dB point was detected at 80 Hz or above. This may happen even if the manufacturer's spec shows that the speaker is capable of playing lower. In fact, there are several benefits at crossing the speakers over at 80 Hz that have to do with power handling and headroom in the bass region that will be handled by the subwoofer amplifier.


The second most common question also relates to Small vs. Large. In the Denon receivers, MultEQ will designate as Large any speaker that has a -3 dB point below 80 Hz. For non-THX speaker systems this is an arbitrary definition that often causes confusion. All it means is that the speaker will not be bass managed unless the user tells it to be. Because Audyssey is not in charge of bass management, we have to abide by the manufacturers' rules and simply report the information found by the measurements to the bass management system.


In situations where the speakers do not play significantly below 80 Hz, an additional step must be taken to make sure that there is no loss of bass information. The user must set the speaker to Small manually so that bass management is performed properly.


Polarity: MultEQ checks the absolute polarity of each loudspeaker and reports it to the user. This is simply a report and does not affect the subsequent calculations in any way. It just asks you to check the wiring to make sure it is connected properly to each speaker. Sometimes we get false alarms. This is usually because the speaker has a driver (usually the mid-range driver) wired out-of-phase intentionally to make up for some problems at the crossover region. If a phase warning is shown, it is not a cause of alarm. Simply check the cables and hit Skip if everything is fine. Again, this does not have any effect on the EQ results.


Subwoofer distance: in many active subwoofers it is not possible to defeat the low-pass filtering. That means that the pre-pro bass management filters will be on top of the low-pass filters inside the subwoofer. The built-in low-filters introduce a delay to the signal coming in (because they have poles). This delay is seen by MultEQ as acoustical delay and is reported in the results. That is why sometimes the subwoofer distance is reported to be longer than the physical measured distance. The setting should not be changed because the blend between the sub and the satellites has been designed based on this time delay.


The design constraints for MultEQ were that it (1) must fit within a small portion of the DSP so that other processes can also run and (2) it must use FIR filters because of the well-known artifacts that IIR filters cause particularly in the time domain response. As it turns out, these two requirements are contradicting. In order for FIR filters to be effective and capable of correcting to low frequencies, they must consist of several thousand coefficients (taps). The problem is that the CPU power required increases with the number of taps, hence the dilemma. What we did at Audyssey was to come up with a different way to partition the frequency axis so that we can use fewer taps and yet not completely give up on low frequency resolution (and therefore low frequency correction). This allows us to take a 512 tap filter that would normally have a resolution of 94 Hz (meaning that any peak or dip narrower than 94 Hz would be missed) and significantly improve its resolving power. The resolution of the filter actually varies continuously with frequency and starts at around 10 Hz. Does this mean that MultEQ can correct an arbitrarily narrow peak or dip at 30 Hz? Of course not. The reality is that in the MultEQ XT version found in receivers, we can correct broader features below 100 Hz better than narrow ones. For example, a lump that is half an octave wide at 50 Hz can be fixed. A narrow dip or peak that is 1/3 or 1/6 octaves wide and centered at 30 Hz will be improved, but not eliminated.


The on-screen display in the receiver has very limited graphics. Therefore it is not possible to really show what the MultEQ correction filter is doing at all frequencies. It appears to only be operating on 9 bands like a parametric equalizer, but this is not the case. What is shown is a very crude approximation to the MultEQ correction and it should not be used to read exact values of cut or boost at the 9 frequencies shown.


Furthermore, there is no display for the subwoofer filter. This doesn't mean that there is no subwoofer correction. It was not added to the display because of interface and memory considerations.


(tips by Chris, CTO, Audyssey Laboratories)
 
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#47,781 ·

Quote:
Originally Posted by davelr /forum/post/21429672



I bet Ed Mullen was happy when your order came in.

Many of us started with SVS long before Ed came in



But over the years it has escalated - a little bit - into Stacking


Here is a picture from one-of-those-crazy-guys-on-the-picture nicked RoKo

(a dedicated Stereo and SVS-man)


Right side
 
#47,783 ·

Quote:
Originally Posted by djbluemax1 /forum/post/21438804


I think he means Audyssey attempts to correct speakers with crappy frequency response.

Well, if he means that then he obviously knows more about MultEQ than anybody else in this thread. As you know I'd love to know more about Audyssey's optimization approach too, so that's why I'm asking
 
#47,784 ·

Quote:
Originally Posted by markus767 /forum/post/21438497


No, the sub crawl method with two subs will only work when the delay between the two subs isn't changed afterwards. Sub EQ HT (I guess that's what you meant by "SubEQXT"?) most likely does change delay between the two subs which removes the sub crawl optimization. So do the sub crawl with both subs connected via Y-cable from a single subwoofer ouput and run MultEQ afterwards with the same cabling.

Yes, just a typo; we're discussing Sub EQ HT (orig post corrected). Though I'd do it as I outlined, hooking the subs up separately after the "crawl"* then run Autosetup and listen/measure and at what Sub EQ HT sets them at. I'd think that would be better because that will time-align the subs with the satellites. Then if it's smoother with the subs firing exactly simultaneously, you can always set the two subs the same to whichever sub is given the greater delay.


*I think we should distinguish this technique from the oft-referenced "sub crawl" by calling it a "measured sub haul".
 
#47,785 ·

Quote:
Originally Posted by SoundofMind /forum/post/21438835


Yes, just a typo; we're discussing Sub EQ HT. Though I'd do it as I suggested, hooking the subs up separately after the "crawl"* then run Autosetup and listen/measure and at what Sub EQ HT sets them at. I'd think that would be better because that will time-align the subs with the satellites. Then if it's smoother with the subs firing exactly simultaneously, you can always set the two subs the same to whichever sub is given the greater delay.


*I think we should distinguish this technique from the oft-referenced "sub crawl" by calling it a "measured sub haul".

By moving the mic you change the delay between the subs. That's why I suggest to have them connected via a Y-cable at all times. The time-alignment needs to stay the same after the crawl and running MultEQ. Changing the time-alignment between the subs will ultimately change their combined frequency response.
 
#47,786 ·

Quote:
Originally Posted by markus767 /forum/post/21438840


By moving the mic you change the delay between the subs. That's why I suggest to have them connected via a Y-cable at all times. The time-alignment needs to stay the same after the crawl and running MultEQ. Changing the time-alignment between the subs will ultimately change their combined frequency response.

Moving the mic? The sweeps are done with mic in MLP, and the mic is in MLP for the first mic position of Autosetup, which is the one that sets the delays.
 
#47,787 ·

Quote:
Originally Posted by markus767 /forum/post/21438840


By moving the mic you change the delay between the subs. That's why I suggest to have them connected via a Y-cable at all times. The time-alignment needs to stay the same after the crawl and running MultEQ. Changing the time-alignment between the subs will ultimately change their combined frequency response.

Um... SubEQ HT isn't going to make the frequency response and time-alignment WORSE than what you get during your sub crawl/lug/whatever.


It might make it *different* than what you measured... but that's the whole point of EQ, isn't it?


Marcus, are you basically saying someone with a calibrated mike and a decent knowledge of REW can get the two subs aligned in such a way that the dual EQ of SubEQ HT would make things worse? Because that's what it sounds like your saying.


If you are just saying it's going to change your preference to it's "reference"...then I guess I agree with you... but if you don't like Audyssey's "reference" why use Audyssey?


Thanks for any clarification you can provide.
 
#47,788 ·

Quote:
Originally Posted by markus767 /forum/post/21438775


Is there any smoothing applied to the graph?

That sweep was done at 1/24th.... I think i could easily level that peak @ 40hz or just leave it for Audyssey to do
 
#47,789 ·

Quote:
Originally Posted by SoundofMind /forum/post/21438866


Moving the mic? The sweeps are done with mic in MLP, and the mic is in MLP for the first mic position of Autosetup, which is the one that sets the delays.

I thought we were talking about sub crawl with two subs ?
 
#47,790 ·

Quote:
Originally Posted by S_rangeBrew /forum/post/21438872


Marcus, are you basically saying someone with a calibrated mike and a decent knowledge of REW can get the two subs aligned in such a way that the dual EQ of SubEQ HT would make things worse? Because that's what it sounds like your saying.

No, that's not what I'm saying. I was just stating the fact that varying the time-alignment between two stationary subs will create a varying response at the main listening position.
 
#47,791 ·

Quote:
Originally Posted by kgveteran /forum/post/21438880


That sweep was done at 1/24th.... I think i could easily level that peak @ 40hz or just leave it for Audyssey to do

That doesn't look right. The graph is way too smooth. How long is the window on the impulse response (make sure about 1000ms of the impulse response are used for the frequency response calculation)? Where did you put the mic? How loud is the sweep? Comparable level to the Audyssey sweeps?
 
#47,792 ·

Quote:
Originally Posted by Flageborg /forum/post/21438726


Nice system you have



You should rather re-locate your existing side-mounted surrounds,

move your right-sided rack and go for wide & height...


more like this plan from Audyssey:


Thanks. Moving my side surrounds isn't an option (as you can see from my theater pics, the right side one is next to an opened wall section) and my rack is there to stay I'm afraid, unless I replace lots of interconnects for longer ones, which isn't an option I'd consider either.


My other "problem" is the baseboard heater I have on the front left side, it would have to be replaced by another type of heating element (can do), since I wouldn't want heat to creap up onto the wide left speaker for a long period of time...not good.


Edit: So basically I did get my answer, front wides should be the next logical location step to get the most out of two additional surrounds.
 
#47,793 ·

Quote:
Originally Posted by markus767 /forum/post/21438886


No, that's not what I'm saying. I was just stating the fact that varying the time-alignment between two stationary subs will create a varying response at the main listening position.

Right. But we are talking about Audyssey doing the changing, which is what it's supposed to do. Using a single sub output with a Y adapter as you suggest for two subs on a SubEQ HT (XT32) equipped receiver can do nothing but cripple it's ability to do what it's supposed to do.
 
#47,794 ·

Quote:
Originally Posted by S_rangeBrew /forum/post/21438969


Right. But we are talking about Audyssey doing the changing, which is what it's supposed to do. Using a single sub output with a Y adapter as you suggest for two subs on a SubEQ HT (XT32) equipped receiver can do nothing but cripple it's ability to do what it's supposed to do.

Not if the two Y-cable connected subs create a situation that is more "EQ-friendly" than the situation with both subs time-aligned by MultEQ Sub HT.
 
#47,796 ·

Quote:
Originally Posted by markus767 /forum/post/21434312


What AVR model? Mains set to large or small? If set to large, is bass also sent to the mains?


Any AVR will work properly. I do not discuss BM much anymore because fuzzy little heads tend to explode when I do so.




Quote:
Originally Posted by markus767 /forum/post/21434312


Again a pretty meaningless graph. Please show the steady state response of sub + L, sub + R and sub + L + R because this is what is heard.


I have them, but no thank you. This is the Audyssey thread, and I have strayed from my stacked subwoofer topic way more than I had intended to do.


I have posted too much info on this subject already. Roger asked about how the system sounds on a subjective basis, and I produced a chart that gives him an idea of the different SPL levels amd FR of one main speaker and one JPC-MBM. Roger can run with that info as far as he wants to. As you know, how a system sounds on a subjective basis is a Geddes specialty. I don't recall ever seeing a single chart made by Geddes on the issue.


I do not use a subwoofer because one is not needed. I use an extra matching speaker (typical 2 way) in a bandpass manner. Easy to locate an to adjust the speaker height with a speaker stand.
 
#47,797 ·

Quote:
Originally Posted by markus767 /forum/post/21438891


That doesn't look right. The graph is way too smooth.

I agree but maybe he has a spectacular room !!
 
#47,798 ·

Quote:
Originally Posted by markus767 /forum/post/21438891


That doesn't look right. The graph is way too smooth. How long is the window on the impulse response (make sure about 1000ms of the impulse response are used for the frequency response calculation)? Where did you put the mic? How loud is the sweep? Comparable level to the Audyssey sweeps?

The level is 84db, where the Audyssey sweeps are about 75db. I used the first mic location of my sofa, they measure about the sames across three seats.


I will checked the impulse and moved it to 1.0ms....did little to the graph. I moved the mic to a few more locations on the sofa and there where small changes, but nothing Earth shattering.


I then moved the mic to one corner and it looked terrible, over to another corner and different, but terrible again.


My plan is to build my first AUX sub based on these measurements. I would like to purchase a MiniDSP, i can shape the 40hz hump and add some delay, as the AUX sub is right next to the right of the sofa.


The BIC-200 sub will do for now. I'm gonna run Audyssey again with the AUX sub in place to see how it measures...who knows the BIC sub may just stay LOL..


I thought you would be happy to see the Geddes multiple sub location prove its self true.
 
#47,799 ·

Quote:
Originally Posted by djbluemax1 /forum/post/21438768



Kal is obviously right on that, especially since you mentioned Audyssey and not a specific version of it. With only a 2.0 system, XT32 and higher could make a BIG difference due to not only the room correction, but especially when coupled with the equally high filter resolution for each of the speakers as previous versions had for the sub channel.



Max



1. I used "Audyssey" generically so as not to be too wordy with technical details.


2. I said "wouldn't benefit that much," not wouldn't benefit.

2a. Let's say it makes a BIG difference ... on two channels. Now, add a subwoofer, surrounds and maybe DSX ... and it makes a much BIGGER difference, doesn't it?


3. The only system that wouldn't benefit that much from Audyssey correction ... any version .. is a 2.0 system.
 
#47,800 ·

Quote:
Originally Posted by pepar /forum/post/21439723


3. The only system that wouldn't benefit that much from Audyssey correction ... any version .. is a 2.0 system.

Actually, it might benefit more. Since, in a two channel system, speakers are placed to optimize imaging AND bass response, the bass response may be worse than in a 2.1 system and hence get even more improvement. Furthermore, experience has demonstrated that many "symmetrical" rooms do not provide symmetrical uncorrected mid and upper frequency response. Audyssey (and other time based room correction systems) can improve, some times dramatically, image stability once the two channels time and frequency responses are more aligned.
 
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