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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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#4,001 ·

Quote:
Originally Posted by audyssey /forum/post/13887075


Brent,


Placing the mic in a single position with the thought that "this is where my ears are" simply doesn't work. There are many reasons for that including the fact that the mic is much smaller than our heads and that the process of hearing is much more complicated than what a mic capsule can deliver.


The perception of bass is highly dependent on the time-evolving and space-dependent pattern of standing waves. A single measurement that happens to place the mic in a room mode dip can be off by 15 dB. Also, it is completely time blind. Human hearing integrates sensation over time before "deciding" what it is that we are hearing. And we also use imperceptible head movements to perform a form of spatial averaging.


So, while it would be great to be able to measure a single point in space with a mic capsule and infer what we actually hear, the reality is that this is a much more complicated process that has to be sampled in space and over time in order to begin to approach what we perceive.


Chris

Thanks Chris

I think most of us think one mic position defines one listening position, and if there is normally only going to be one person listening, then only one test/mic location is necessary.


What you have said has really make me realise the importance of multiple test locations even if most listening is only done at one or two locations.


Thanks.
 
#4,002 ·
This is a little off topic but it does demonstrate how a perfectly calibrated audio system can immerse you in a virtual sound field. It is called a binaural recordings and the technology is being incorporated into the home theater realm such as the Smyth Virtual Surround system. YOU MUST LISTEN WITH HEADPHONES to get the effect.

A binaural recording is actually made by placing microphones in the ear canal and recording the image precisely as a human would hear it. The SVS takes it a step further and allows you to calibrate a headphone to your personal audio characteristics and apply that data to any surround sound track.

This is really an amazing demonstration you will not want to miss.

http://www.youtube.com/watch?v=IUDTl...JA/default.jpg
 
#4,003 ·

Quote:
Originally Posted by sdurani /forum/post/13886000


The author of the article is a long-time Anthem fan. For example: in his review of the AVM-20 a few years ago, he defended Anthem's use of a single global crossover point for all speakers, saying that having independent crossovers for each speaker group "can actually cause more harm than good". So take his review of Anthem's room correction feature in that context.

I just checked over on the Anthem D2 thread, and Kal Rubinson appears to have his hands on a review unit with ARC, so hopefully in time we'll see a review in Stereophile comparing to Audyssey, and perhaps Sherwood/Trinnov.


I don't know what the merits of the ARC might be in terms of sonic effects vs Audyssey - maybe better, maybe worse - but from the review in Secrets, I do really like 2 features or the ARC:


- ability to store and recall 2 custom curves


- ability to do a re-calibration myself without bringing in an Audyssey dealer at considerable expense, any time I change speaker positions, furniture, listening positions, acoustic treatments, room decor, etc.
 
#4,004 ·

Quote:
Originally Posted by syswei /forum/post/13887682


- ability to do a re-calibration myself without bringing in an Audyssey dealer at considerable expense, any time I change speaker positions, furniture, listening positions, acoustic treatments, room decor, etc.

I would expect that from a pre/pro that cost around $7000.


RayJr
 
#4,006 ·

Quote:
Originally Posted by syswei /forum/post/13887779


Not if it is the $7000 Denon AVP. You can't unlock the full callibration capabilities of the Audyssey in that one without paying each time for an Audyssey dealer callibration, right?

Syswei,


No, that's not right. The AVP1 HD and all products with MultEQ XT can run the full version of Audyssey any time one wishes with no installer or additional costs. Some products that are also Audyssey installer-ready allow an installer to perform an optional more advanced calibration using their laptop. In the AVP1 HD Audyssey Dynamic EQ can be turned on after running the built-in version of MultEQ XT.


Chris
 
#4,007 ·

Quote:
Originally Posted by Nordo /forum/post/13887377


Thanks Chris

I think most of us think one mic position defines one listening position, and if there is normally only going to be one person listening, then only one test/mic location is necessary.


What you have said has really make me realise the importance of multiple test locations even if most listening is only done at one or two locations.


Thanks.

Nordo,


You're right, most people associate mic positions with seats. It's best to think of the mic positions as points in space that "sample" the listening area.


However, just taking a bunch of measurements isn't enough. It took us several years of experimentation at the university lab to figure out what to do with them. The simplistic approach is to average them. But we quickly found that averaging is a very crude approach. For example, if one location has a dip at 100 Hz and a nearby location has a peak at 100 Hz, then averaging will add them and divide by 2. The result will be an apparent flat response at 100 Hz and the EQ filter will do nothing there. The other problem with averaging is that it gives equal importance to every measurement when, in fact, some acoustical problems in the room are much more severe than others. So, we had to come up with a method that uses acoustical and perceptual "rules" as to what importance to give to each of the measurements when combining them. Developing that part of the algorithm took about 5 years of research from my PhD student (now VP of Research at Audyssey), Sunil Bharitkar.


Chris
 
#4,008 ·

Quote:
Originally Posted by audyssey /forum/post/13887884


Syswei,


No, that's not right. The AVP1 HD and all products with MultEQ XT can run the full version of Audyssey any time one wishes with no installer or additional costs. Some products that are also Audyssey installer-ready allow an installer to perform an optional more advanced calibration using their laptop. In the AVP1 HD Audyssey Dynamic EQ can be turned on after running the built-in version of MultEQ XT.


Chris

Maybe you call that "the full version of Audyssey", but if I'm paying $7k for a prepro, I'd rather have what you call "an optional more advanced calibration using [an installer's] laptop" or what the Audyssey website terms "For even higher performance, a professional installation can be performed by an Audyssey-Certified Installer." I'd rather not pay for repeated re-callibrations as I make changes to the room, which is one feature of the Anthem ARC that is more appealing than Audyssey.
 
#4,009 ·

Quote:
Originally Posted by syswei /forum/post/13887997


Maybe you call that "the full version of Audyssey", but if I'm paying $7k for a prepro, I'd rather have what you call "an optional more advanced calibration using [an installer's] laptop" or what the Audyssey website terms "For even higher performance, a professional installation can be performed by an Audyssey-Certified Installer." I'd rather not pay for repeated re-callibrations as I make changes to the room, which is one feature of the Anthem ARC that is more appealing than Audyssey.

syswei,

I don't know if you have been following the Anthem thread..but there are still a bunch of problems with ARC...and it is no were near as proven or stable as Audyssey..yet...if ever. Audyssey pro is an option that is not for everyone...kind of like ISF calibration of a display.


RayJr
 
#4,010 ·

Quote:
Originally Posted by audyssey /forum/post/13887946


Nordo,


You're right, most people associate mic positions with seats. It's best to think of the mic positions as points in space that "sample" the listening area.


However, just taking a bunch of measurements isn't enough. It took us several years of experimentation at the university lab to figure out what to do with them. The simplistic approach is to average them. But we quickly found that averaging is a very crude approach. For example, if one location has a dip at 100 Hz and a nearby location has a peak at 100 Hz, then averaging will add them and divide by 2. The result will be an apparent flat response at 100 Hz and the EQ filter will do nothing there. The other problem with averaging is that it gives equal importance to every measurement when, in fact, some acoustical problems in the room are much more severe than others. So, we had to come up with a method that uses acoustical and perceptual "rules" as to what importance to give to each of the measurements when combining them. Developing that part of the algorithm took about 5 years of research from my PhD student (now VP of Research at Audyssey), Sunil Bharitkar.


Chris

Thanks for the peek into the R&D of Audyssey and MultEQ. Fascinating stuff, even for a layperson like me. And like any good scientific instrument, you will only get the best results out of it if you set it up properly and use it properly.


Thanks again.
 
#4,011 ·

Quote:
Originally Posted by syswei /forum/post/13887682


I just checked over on the Anthem D2 thread, and Kal Rubinson appears to have his hands on a review unit with ARC, so hopefully in time we'll see a review in Stereophile comparing to Audyssey, and perhaps Sherwood/Trinnov.

As you said earlier, the more reviews the better. Looking forward to what Kal has to say.
Quote:
I do really like 2 features or the ARC:


- ability to store and recall 2 custom curves


- ability to do a re-calibration myself without bringing in an Audyssey dealer at considerable expense, any time I change speaker positions, furniture, listening positions, acoustic treatments, room decor, etc.

I agree with wanting the first feature, moreso to A/B different results in order to choose which one to keep. Since the room itself doesn't change, I doubt I'd use more than one room correction curve.


The second feature, as Ray pointed out, is more akin to wanting an ISF video calibration every time you bought a lamp or changed to different type of lightbulb. You already have the ability to do a re-calibration yourself, without bringing in an Audyssey dealer.


Sanjay
 
#4,012 ·

Quote:
Originally Posted by sdurani /forum/post/13888637


As you said earlier, the more reviews the better. Looking forward to what Kal has to say. I agree with wanting the first feature, moreso to A/B different results in order to choose which one to keep. Since the room itself doesn't change, I doubt I'd use more than one room correction curve.

My room changes. For example, this season, we have the windows open but in the depths of winter/summer, we have them closed. Makes a big difference. OTOH, I change equipment so frequently that I have to recalibrate all the time.
 
#4,013 ·
You know, I must say.... As novel and idea for the end user as auto calibration is, I have to say I have never found a system with auto calibration that can make a system sound better than I can with my ears alone. The auto calibration always gives a good reference, but there are always little tweaks to be made.
 
#4,014 ·

Quote:
Originally Posted by Jkeith247 /forum/post/13889074


You know, I must say.... As novel and idea for the end user as auto calibration is, I have to say I have never found a system with auto calibration that can make a system sound better than I can with my ears alone. The auto calibration always gives a good reference, but there are always little tweaks to be made.

It depends, of course. You can make it sound better to you by tweaking it to your satisfaction. OTOH, you would have a difficult time making it flat and accurate by ear alone. And that says nothing about fixing decay problems. Sophisticated instrumentation, auto or otherwise, is the only way to achieve/approach that.


But you needn't bother if you think otherwise.
 
#4,015 ·
A good example of what Kal is referring to is what Audyssey did to my subs. I have the installers kit and do my own Pro calibration. When I completed the process, my subs were set much lower than I would have set them on my own. However after living with them for awhile, they actually sound not just better but much better! Most of us set our subs too hot and they end up with a lot of volume and boom. Now i have maybe less volume, but more tight bass. It is much more real sounding with no boom or bloat to the sound.


That is how it sounds to my ears and may not sound the same to others.
 
#4,016 ·
" http://www.youtube.com/watch?v=IUDTl...JA/default.jpg "


Very cool, though w/my old Denon headphones the sound didn't seem to want to go into the forward hemisphere.


"I agree with wanting the first feature, moreso to A/B different results in order to choose which one to keep. Since the room itself doesn't change, I doubt I'd use more than one room correction curve."


Some of us change listening positions, audio vs HT in my case, so more memories is very desirable.
 
#4,017 ·

Quote:
Originally Posted by noah katz /forum/post/13889517



Very cool, though w/my old Denon headphones the sound didn't seem to want to go into the forward hemisphere.

Hi Noah,


You've stumbled across the main limitation of 3D audio over headphones: the inability to render an external front image. The main reason for this is due to the fact that the mannequin that was used to record the haircut has pinnae that are shaped for the "average" ear. Unfortunately, we all have pinnae that are significantly different from the average. So, while mannequins are good for making measurements they are not great at making recordings.


The Smyth Research system solves this problem by taking individual measurements for each user. These are called head-related transfer functions (HRTFs) and vary from person to person so much that it is impossible to simulate them with one model.


I recently heard a demo of the Smyth Research system and it was truly astounding. They had a 5.1 system with B&W speakers in the room and a set of Stax headphones with their HRTF-based system running. In addition, they had convolved the acoustics of the room we were in with the HRTFs. The demo started with the 5.1 system playing and then the user put on the headphones. An IR tracker knew when you head the headphones on and muted the speakers. It also kept the world pointing forward even when you turned your head. The effect was stunning. It was impossible to tell the difference between the real center channel 6 ft. in front of me and the virtual center channel in the headphones.


BTW, the haircut piece on youtube not only has nothing to do with Smyth Research it is a knockoff of the original done by Holophonics 10+ years ago.


Chris
 
#4,018 ·

Quote:
Originally Posted by Rayjr /forum/post/13888309


syswei,

I don't know if you have been following the Anthem thread..but there are still a bunch of problems with ARC...and it is no were near as proven or stable as Audyssey..yet...if ever. Audyssey pro is an option that is not for everyone...kind of like ISF calibration of a display.


RayJr

I have not studied the thread much of late, but I have read that ARC is somewhat buggy at this point. From what I understand though, Anthem has a decent history of upgrades/fixes to its products, and in my personal situation, I don't expect to be purchasing for at least 6 months anyway. Who knows, by the time I'm ready, there might be a D3 and/or a next-generation Audyssey from which to choose.
 
#4,019 ·

Quote:
Originally Posted by sdurani /forum/post/13888637


I agree with wanting the first feature, moreso to A/B different results in order to choose which one to keep. Since the room itself doesn't change, I doubt I'd use more than one room correction curve.

I think there are other reasons for wanting more than one custom curve: what Kal mentioned (open/closed windows/doors); what the Secrets reviewer mentioned (one curve optomized toward a single seat, another optomized toward a "full house"); a situation where the user has a retractable PJ screen, but likes to have it retracted when listening to music.
 
#4,020 ·

Quote:
Originally Posted by nethomas /forum/post/13889280


A good example of what Kal is referring to is what Audyssey did to my subs. I have the installers kit and do my own Pro calibration. When I completed the process, my subs were set much lower than I would have set them on my own. However after living with them for awhile, they actually sound not just better but much better! Most of us set our subs too hot and they end up with a lot of volume and boom. Now i have maybe less volume, but more tight bass. It is much more real sounding with no boom or bloat to the sound.


That is how it sounds to my ears and may not sound the same to others.

We get used to a particular sound and adapt to it. After a while it sounds "right" to us. Make an audible change and we seem to automatically assess the new sound as "wrong" when, actually, it's just unfamiliar. If we take the time to adjust and let the new sound become familiar, we can start to assess it for what it is rather than for what it does differently to the old sound, and when we reach that point we can finally start to decide whether the new sound is better or worse than the old. While we're still in direct comparison mode just noticing how things have changed from a sound that we liked, we have a strong tendency to assess the changes as being not as good because we're expecting something different, we're expecting the familar. While the new sound is unfamiliar the differences stick out like "sore thumbs" and we're about as happy with them as we would be with a sore thumb.


Familiarity takes a bit of time to develop. One trick I've learned over the years that can help in getting a feeling for the new sound more quickly, before we've achieved familiarity, is to listen to something totally newsomething I've never heard before. That means I can't make comparisons about whether or not some aspect sounds different, or better or worse than it did before, and my judgements are then much more firmly based on what I'm hearing rather than on comparisons with what I remember.
 
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