Audyssey MultEQ: Questions and Answers - Onkyo, Denon, et. al. - Page 5

JeanPaul · 05-03-2008, 09:29 AM

Chris,

Thanks so much for your advice here...greatly appreciated I'm sure by all.

One question I have. I'm using Klipsch bookshelves. Ive read to try and keep crossover at around 80Hz. After using Audyssey it sets the fronts to 40Hz and center to 80Hz. Should I keep it as such or do you think recalibration is needed?

Thanks again,
JP

highliner · 05-03-2008, 09:32 AM

Dear Chris,

Please don't get me wrong, I believe Audyssey is just a brilliant system!

My main concern, nevertheless, is to get the maximum out of it for my particular case and, if you do not mind, I'd like to ask for your additional opinion on the matter described below...

Firstly, all I care about is to get the best possible set up for the Main Listening Position (MLP) only.

Secondly, as I understand the logic of the Audyssey system, it tries to generate some equalizer curve, which would allow to avoid some parasite frequencies for each and every set up position (e.g. 1-8) used.

So, let say we have a frequency pattern ABCD, which is perfect for the Main Listening Position. However, if frequency A is not good for position 2, then it is being either cut off or decreased, which is good for position 2, but is affects the frequencies reaching the MLP, i.e. the MLP suffers from it.

So, once we run through all 8 positions, we do get the equalizer curve, which makes all 8 folks in the theatre enjoy the show, however, at expense of the Main Guy sitting at the MLP...

I hope it all makes sense... Please correct me, if my logic is wrong...

I would greatly appreciate your recommendation as to the best way to set up the MLP only. So far, I have done it based on 3 points (the main one plus 2 on each side about 50-60 cm from the MLP). I must say, it does sound very very nice! However, if there might be a better way, I would really like to know it ))).

To ALL: I've got the best result after having:

- turned off all and every system in the room with a ventilator/cooler;
- turned off TV!!! (42" Panasonic full HD works quietly, but it does make some background noise...); the auto set up can be done based on indicators on 3808;
- avoided using the master Remote Control of 3808, which makes a high frequency squeeking noise, when the blue screen is on... The secondary remote was used instead...

audyssey · 05-03-2008, 10:34 AM

Quote:

Originally Posted by JeanPaul

Chris,

Thanks so much for your advice here...greatly appreciated I'm sure by all.

One question I have. I'm using Klipsch bookshelves. Ive read to try and keep crossover at around 80Hz. After using Audyssey it sets the fronts to 40Hz and center to 80Hz. Should I keep it as such or do you think recalibration is needed?

Thanks again,
JP

JP,

If the Klipsch speakers are placed near the wall it's common for them to show bass extension due to the help they get from the wall surface. I would recommend setting them to 80 Hz manually. No recalibration is needed if you do that.

Chris

audyssey · 05-03-2008, 10:45 AM

Rolan

Quote:

Originally Posted by highliner

Secondly, as I understand the logic of the Audyssey system, it tries to generate some equalizer curve, which would allow to avoid some parasite frequencies for each and every set up position (e.g. 1-8) used.

So, let say we have a frequency pattern ABCD, which is perfect for the Main Listening Position. However, if frequency A is not good for position 2, then it is being either cut off or decreased, which is good for position 2, but is affects the frequencies reaching the MLP, i.e. the MLP suffers from it.

So, once we run through all 8 positions, we do get the equalizer curve, which makes all 8 folks in the theatre enjoy the show, however, at expense of the Main Guy sitting at the MLP...

I hope it all makes sense... Please correct me, if my logic is wrong...

MultEQ doesn't really work that way. The first thing to understand is that "position" doesn't necessarily mean "where people sit". For example seats far off-axis or near the side walls are common, but one should not measure there because the drop-off in high frequencies that most speakers have off-axis causes unnatural correction results.

The core of the MultEQ method is how the multiple measurements are combined. It does so by trying to avoid exactly what you mention above. So, after all the measurements are taken an analysis of the patterns in each position is performed and then the measurements are grouped into clusters with similar problems. A representative response is synthesized for each cluster that contains the acoustical problems found in that part of the room with the appropriate weighting (bigger and more common problems get more weight). Then the representative responses from all the clusters are combined to synthesize one final room representation that contains all the appropriately-weighted information about the problems in the area measured. Furthermore, this is done in the time domain so information about reflections is captured. The MultEQ filter for each channel is then created by inverting that combined response and applying certain psychoacoustic rules to maximize the correction while keeping the filter length small (to avoid taking up too much DSP processing).

Quote:

I would greatly appreciate your recommendation as to the best way to set up the MLP only. So far, I have done it based on 3 points (the main one plus 2 on each side about 50-60 cm from the MLP). I must say, it does sound very very nice! However, if there might be a better way, I would really like to know it ))).

This is a good approach, but I would recommend taking more measurements. Take three more parallel measurements about 50 cm in front of the first three. Then take the final two closer to the MLP (25 cm to the left and right and slightly forward forming a triangle around where your head would be).

Let us know how that works out.

Chris

highliner · 05-03-2008, 12:38 PM

Dear Chris,

thank you for your reply and the recommendations.

Quote:

Originally Posted by audyssey

Rolan
This is a good approach, but I would recommend taking more measurements. Take three more parallel measurements about 50 cm in front of the first three. Then take the final two closer to the MLP (25 cm to the left and right and slightly forward forming a triangle around where your head would be).

Let us know how that works out.

Presently, I seem to have the "lucky curve" I am most happy with and I would hate to lose it

1. Can you please confirm that, if I copy the Audyssey curve to the 'Manual' file in 3808, I would get exactly the same equalizer curve saved there and not some simplistic representation?

2. Also, as i mentioned before, in my case, the set up is made with only 2 front speakers hooked up (all times I tried 5.1 Audyssey auto set up, the 2 channel Stereo mode would not sound as nice, as auto set up run with only 2 front speakers initially hooked up and all other speakers unhooked; in 5.1 mode it does sound nice (perhaps the sub and the center/surround speakers compensate for the missing frequencies), but why would I listen to a music concert in 5.1? I mean, I see a concert scene in front of me and hearing some sounds from the surround speakers located behind me does not sound too natural, right?...).

So, do you believe your advice to make more measurements still applies to the auto set up with only 2 front speakers?

Sorry to bug you with such questions, which would probably be more applicable to a set up of 2 channel stereo amplifier...

Brgds,

highliner
Odessa, Ukraine

P.S. there are quite a few folks from Russia/Ukraine following our discussion with interest...

P.P.S. My personal opinion, you deserve a monument for first developing this kind of system and, then, for convincing the manufacturers to have it included into their production units. No kidding.

audyssey · 05-03-2008, 01:36 PM

Highliner,

Quote:

1. Can you please confirm that, if I copy the Audyssey curve to the 'Manual' file in 3808, I would get exactly the same equalizer curve saved there and not some simplistic representation?

No, the copy to Manual does not preserve the same curve. Manual is not a mode supported by Audyssey. It is a very crude approximation of the many hundreds of MultEQ filter coefficients by 9 parametric bands. Also, all time domain correction benefits of the MultEQ FIR filters is lost by moving to Manual EQ.

Quote:

2. Also, as i mentioned before, in my case, the set up is made with only 2 front speakers hooked up (all times I tried 5.1 Audyssey auto set up, the 2 channel Stereo mode would not sound as nice, as auto set up run with only 2 front speakers initially hooked up and all other speakers unhooked; in 5.1 mode it does sound nice (perhaps the sub and the center/surround speakers compensate for the missing frequencies), but why would I listen to a music concert in 5.1? I mean, I see a concert scene in front of me and hearing some sounds from the surround speakers located behind me does not sound too natural, right?...).

That is very strange. The MultEQ filters are completely independent in each channel. Thus the front channels will have identical filters whether you run 2.0 (2.1) or 5.1 calibration. No sharing of signals across channels is performed by MultEQ as that would compromise imaging. Perhaps the perceived differences are due to different bass management settings in the two cases?

I also disagree with the notion that "a concert is in front so I should only listen from the front". In a real concert hall, a very large portion of the sound energy arriving at your ears is from reflections that occur from the side walls, the ceiling and other surfaces. These arrive within a few tens of milliseconds after the direct sound and have been found to greatly influence human perception of width and depth. After those first few milliseconds, sound is still bouncing around the room, but now the reflections become more random and are not identified with a specific direction. This is called the reverberant field and greatly contributes to the richness of sound. This is what distinguishes the best acoustic spaces from the bad ones. In psychoacoustic research it has been shown that we can not perceive reflections and reverberation if it is coming from the same direction as the direct sound. So, playing all that information from the front speakers only prevents you from enjoying the space in which the music was recorded.

Unfortunately, the reproduction of music over surround systems isn't always ideal. This is due to many reasons including the lack of understanding by some recording engineers of how to use microphones in the space and how to mix for multichannel. The film industry is decades ahead of the music industry in that respect. Many of the simulated surround modes suffer from the same issues. But there are great surround music recordings that can almost make you believe you are in the performance space.

Quote:

So, do you believe your advice to make more measurements still applies to the auto set up with only 2 front speakers?

Yes! More measurements will give the algorithm more information with which to work and you will notice differences, particularly in the low frequencies. Just don't measure too far away from the center position as I described in my previous post.

Chris

PS. I really appreciate your nice words about our work and our products

highliner · 05-03-2008, 03:14 PM

Dear Chris,

Thank you for all your kind and detailed explanation! It is greatly appreciated!

I am still enjoying the option of set up I presently have and will give it more tries later on...

You are right in that the low freqs seem to be on the low side, but the articulation of all other frequencies are so great and the sound flows so effortlessly and with such nice air, that I am ready to sacrifise some low freqs for that (at that, increasing the level of bass through tone control is always an option).

A silly question, if I may, how critical is it to use a tripod for the mic? Holding it in one's hand (provided that the speakers are not blocked by one's body) is not a good option?

audyssey · 05-04-2008, 09:59 AM

Quote:

Originally Posted by highliner

A silly question, if I may, how critical is it to use a tripod for the mic? Holding it in one's hand (provided that the speakers are not blocked by one's body) is not a good option?

Holding the mic is not recommended. The handling noise can affect the performance at low frequencies. A tripod is really the best way to mount the mic for measurements.

Chris

john a hunter · 06-03-2008, 01:18 AM

Chris, I need your help. I purchased a Denon 2808 last November for use as a pre-pro. The Audyssey programme has given my system a shot in the arm and it has never sounded better, that is until yesterday.

About a month ago I replaced my Sony 60”SXRD with a 70” and then recalibrated my sound system. I have Martin Logan Aerius for LF and RF and their Cinema centre. It sounded great. However over the weekend I read your earlier post about using setting up positions 7&8 to form a triangle with your head in the primary seating position. As I listen to a lot of music on SACD MC, I decided to give it a try. There have been no changes to my listening room since my last Audyssey calibration. However, after this calibration the sound is now harsh and bright.

The crossover went from 40 for the Centre and 110 for the surrounds to 100 for both. Centre level went up from -3 to +1.5. More importantly there is now a very hard sharp sound across the entire front sound stage.

EQ for FL went from -1 AT 500Hz to +0.5, from1 at 1kHz to +3.5 and while previously 2, 4, 8 and 16 were+2.5, +5.5,+5.5 and +3.5, they are all now+6.

For FR, 1kHz has gone from -4 to+2.5, 2 from-4.5 to +6 and 4,8and 16 from+6, +5.5 and +3 , all to +6 again. It is not surprising that the sound is so bright. I have run the programme two more times using my earlier set up positions but it always comes back to these settings.

Why has the top end been recalibrated to max high frequency? What did I do wrong and how to I get back to the old settings. Please help.

audyssey · 06-03-2008, 01:54 AM

Hi John,

The symptoms you are describing sound like something has happened to your microphone. Humidity can cause it to exhibit a drop in high frequencies and that would fool MultEQ into boosting more there. Or it could just be damaged. How was it stored?

Chris