Microphone placement?

When calibrating my system with MultEQ, where should the microphone be placed?

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208 Comments

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    Audyssey Labs

    Hi Owen,

    Audyssey sets the levels to achieve two things: (1) every speaker is set to play at the same level as the other speakers and (2) the system plays at film reference level when you set the master volume control to 0 dB.  This is called reference calibration.  

    Every speaker will have a different level because of its design (sensitivity) and distance from the listening position.  So, it will require a different adjustment.  For example, if you were sitting farther away, the level setting would be higher to achieve the same loudness.

    The level is not really related to how close it is to a wall or corner.  These will cause problems with the frequency response and that is addressed by the Audyssey room correction filters in MultEQ.

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    Owen Heuston

    That makes sense since the center is the closest speaker in relation to the listeneing position.  Problem is, I feel that I don't like the lower volume of the dialog setting because of the -6 setting.  Should I try playing with the reference level and see if that helps?

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    Audyssey Labs

    If you change the level of just the center speaker then you are changing the soundstage balance.  It's OK to do that, but I wanted you to know what it would do.  Remember, the –6 dB setting is just a relative number that is needed to bring this speaker in balance with the others.  The reference level can't be adjusted.  Perhaps you are referring to the Reference Offset Level? That is intended for something else: Dynamic EQ.  It tells it how much compensation to provide if you are listening to content (such as TV or Music) that is not mixed to film standard levels.  More info here: http://ask.audyssey.com/forums/84181/entries/73283.html

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    Owen Heuston

    Yes, sorry I meant the reference offset level(I am at work and was distracted while typing).  I will leave it at -6 and just get used to it.  I am sure it will sound fine to me after a while.  Thanks for the quick response and valuable info.

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    Audyssey Labs

    OK. There's nothing wrong with turning up the center channel level for personal preference.  I was just trying to explain the difference between Reference and Preference.

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    Neilson

    Chris, can you comment on this statement:

     

    I usually sit normally in my MLP while running Audyssey. (except for the first measurement, which is at the MLP) Since I use a boom stand, I can curl under the mic for the first measurement.

    The way I see it, I am part of my room response. Therefore, I should be sitting in my seat

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    Neilson

    I explained the way I ran my calibration which I got from you on facebook.  I honestly looked around to try and explain why to this gentleman why you dont sit in the seats that you are calibrating, but couldnt really find a great answer other than your body,hands,etc.. causing reflections. 

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    Audyssey Labs

    Your explanation was good.  It's a bad idea to have a person near the mic.  The reflections from our body will interfere with proper measurements especially at higher frequencies.

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    Markus

    Hi Chris,

    In your "How to MultEQ" guide at http://www.audyssey.com/sites/default/files/attachments/onesheet_howtomulteq.pdf mic position 1 is not where I would expect the listeners head. On a normal couch with no high back the head is probably closer to point 7 and 8. Is there a reason for this?

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    Audyssey Labs

    The dots are just a representation of the approximate locations.  They are not drawn to be accurate to the mm...  The first mic position should be where the center of your head is.

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    Markus

    Thanks Chris. So I guess points 2, 3, 4, 5 and 6 should also be moved backwards? Is there a preferred pattern for choosing the other points other than a 2 feet spacing from the first position? I'm thinking of symmetry vs. random, same number in front and behind point 1, same number to the left and to the right of point 1, circle around position 1, etc.

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    Audyssey Labs

    The preferred pattern is as shown in the diagram.  One reason for not putting the points up against the back of the couch is to make sure that people don't put the mic on the couch--we found that many do because they don't use a tripod.  That's not a good idea...

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    Markus

    So just to clarify, when using a boom stand that brings the mic to ear height, a single free-standing couch (not against the back wall)  for 2-3 persons with low back (nothing blocking sound from the back to the ears) and 8 mic points, your recommendation for best results is...

    a) Position 1 = center of head at main listening position

    b) Position 2 & 3 = approximately 2' to the left and the right of position 1

    c) Position 4, 5, 6 = approximately 2' in front of 1, 2 and 3

    d) Position 7, 8 = approximately 1' from each other and in the back of position 1

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    Audyssey Labs

    Hi Markus,

    Yes, that's the right idea.  If the couch is against the back wall, then you should make sure that none of the mic positions are closer than 50 cm from the wall. 

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    Milan Bodlovic

    Hi Chris,

    I have Marantz receiver NR1402 with Audyssey EQ and KEF Q spakers in 5.1 configuration, room is about 5*6meters , front L/R speakers are floor standing model 2,5 meter apart. Primary seating position on about 2/3 back of room in front of centre speaker (quite normal setup).

    Audyssey setup went well and all parameters measured by system  -  number of speakers, distance and so on looks OK, after calibration speakers are set as small with 80 Hz crossover.

    When I first played some music in this system I was really happy with subwoofer integration and most of things system did. Sound of high frequencies , lets say from 5kHz up, on the other hand was pretty "bright" - "in you face", unusual.

    I checked what system did to speakers and it set left, right and centre level to -7dB and in  MultyEQ it set f50m 60Hz to aprox. 2kHz +/- 0,5dB boost /cut but in range from 5kHz it applied boost from +4dB to +6dB. I repeated measurement several times (slightly different mic placement, turned down plasma screen that make some noise,  removed 2 chairs to see if they make problems for mic...) and it pretty much gives same results.

    Surround speakers are set by system +2dB level and in EQ they receive only modest boost up to 1dB in 16kHz in same range.

    Could such strange boost in high frequencies be because of microphone placement or some other error during measuring. I have read all documents regarding this and applyed all suggestions and rules,.

    I know this is very general question to have definitive answer but still I am puzzled by results. Some people suggest it is because of KEF UniQ mid/hi drivers in strange configuration Audyssey system is not measuring correctly - but it makes no sense to me - driver is a driver...

    I would not object to what system produced as result if treble range did not sounded really unnatural to me and several other people. 

     

    Any suggestion is welcome.

    Best regards,

    Milan

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    Audyssey Labs

    Hi Milan,

    I don't think it is a microphone issue because then all speakers would have a high frequency boost.  It is most likely a combination of speaker response and mic placement.  Is the mic placed at the same level as the tweeter?  If not, this can cause issues with speakers that have off-axis high frequency roll off.

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    Milan Bodlovic

    Thank you for your suggestion.

    Mic was placed at ear level as suggested by measuring instructions, this would put mic above tweeter level by maybe 5 inches, I can try new measurement with mic positioned at tweeter level and see what values EQ system calculates this time.

     

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    Bhanu

    Chris...thanks for consistently helping/replying.    I had a conversation in the past about how the sound is a bit too bright after Audyssey...specifically that the voice in the song seems a bit "cut off".  That is, I felt that when the micro adjustments are made to the reflections, the fullness of the voice is also partly cut off.

     

    The comment above is re-prompting me with 3 questions please :

    1. So, mic level to tweeter is more appropriate than ear level ?

    2. What exactly is off-axis roll off ?...tried to google but did not get a clear answer.

    3. Whether B&W speakers (684) are one of these that are impacted by this off-axis roll off that can cause the speakers to be a bit too bright etc.

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    Bhanu

    Also related to this is whether it is better to have speakers toed-in for measurements...

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    John Orlando

    Hi Chris,

    Is it possible to use audyssey with a wireless speaker kit for fronts and center. I have a projector so my denon avr is in the rear of my living room along with all of my equipment. I rad audyssey setup and my fronts and center always measures distance at 27.5 ft when they're really around 7.5 ft from the mic position 1. My surround speakers and sub measures just about right.

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    Audyssey Labs

    Hi John: yes it's possible.  Wireless systems add a significant delay to the signal and Audyssey sees that and compensates for it so that all speakers are at the same "distance".

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    Audyssey Labs

    Hi Bhanu,

    I don't fully understand the comments.  "Too bright" and "cut off" seem opposite to each other.  In any case, the best setups have the tweeters at the same level as the ears.  If the tweeters are not at ear level then the mic height should most likely be at ear level.  With some troublesome (e.g. ribbon) tweeters some experimentation is needed to make sure the mic is not in a null of their directivity pattern.

    Tweeters are very directional.  As you move off their center axis their energy starts to diminish.  If you measure there the software will think there is not enough high frequency content and overcompensate.  That's why it's generally best to point the speakers to the listener.  This is true even if you don't have room correction.  The speakers are designed to give their best performance on-axis.

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    John Orlando

    I tried changing the distance manually but it didn't sound right so I changed it back and it sounds better. I have no issues how it sounds but would like to know if theres a way to make it better and if dynamin eq works with this setup.

    Thnx

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    John Orlando

    Great! thnx for your reply

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    Audyssey Labs

    Yes, Dynamic EQ works with this setup just fine.  The distances should be left as found by Audyssey.

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    Bhanu

    I don't fully understand the comments.  "Too bright" and "cut off" seem opposite to each other.**

    Sorry for being a bit vague there.  I meant that the voice seems a bit shrieky sometimes and I tried to say that it could be because some of the midrange frequencies that give the voice a "fully body" might be cut off or missing.    At one point in the past I was heavily using bypass L/R a lot as I loved the Dynamic EQ (I usually put just on...not the day/night etc.)....but could not tolerate the voice in regular Audyssey.   With a recent recalibration in a hardwood room, I started listening in Audyssey flat.

    I will recalibrate with speakers toed-in.   I already notice significant imaging improvement with toe-in.   I had in the past avoided toe-in due to the "wife factor" as people sometimes refer to it -:)

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    Milan Bodlovic

    I have done recalibration with mic placed at tweeter level (as it happens it is just 1,5 inches from ear level), while I was at it I also did with toed in speakers and speakers facing forward. Regarding off axis response - speakers I have are of KEF UniQ design that are made to have better off axis response.

    My final measurement regardless of positioning and placement of speakers is just 1dB different than previous-  4-5 dB boost in high frequencies.

    Even if ithis boost was needed to make speaker response flat  unnatural brightness maybe has more to do with loss of dynamics and other things associated with EQ boosting.

    It would make more sense to apply cuts not boosts to make flat response but this probably is not decision made by audyssy measuring but AVR manufacturer on how to implement measurement.

    But this has nothing to do with mic placement and this tread...

    Regards,

    Milan

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    Robert M. Bridi

    Hi Chris,

    Thank you for all the helpful comments.

    Regarding the first measurement, what do you mean by "center-most position of the listening area"?  Is it the centre between the front main speakers and the rear speakers?  I thought the first measurement position is the main listening position, which in my room is not the centre-most position.

    Thanks in advance.

    Rob

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    Audyssey Labs

    Hi Rob,

    I mean the center with respect to the L and R speakers.  In most cases, this is the main listening position.  But, sometimes people use an off center position.  We recommend not using that as the starting point unless there will never be another person listening to the system.  The delays and levels are calculated from the first mic position so if you start off center it will really skew this for all other positions.

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    Chris Joenck

    Chris,

    I have been struggling with a NAD T775 setup all day today. I get polarity warnings and when I re-run the setup, the warning disappears. It seems very random. I also get 0 feet distance detected in the auto setup. Sometimes the center speaker is detected as large, sometimes small - again random. The detected cross-over frequency hovers between 40hs and 70hz. In your experience, how accurate are these measurements.

    Dynamic EQ sounds too bass heavy and dialog is washed out to the point where it is hard to follow dialog.

    Any suggestion is very much appreciated.

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