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

    I agree with Alex on the reasons for biamping, but the benefits are minuscule compared to the benefits of expanding the soundstage with Wides and/or Heights.

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    GianCarlo Bregaglio

    Hello Chris,

    I have an Onkyo TX NR809 with MultEQ XT.  My couch is identical to the diagram, but it is up against the wall.  I have a few questions:

    1) Can mic position 4-6 be placed at ear height taking into account that listeners are sitting on the floor at those location?  Is that too much of a vertical difference compared to the mic height when taking measurements 1-3?

     

    2) Where should I place the mic for position 7 & 8 being that my couch is against the wall?

     

    Thank you for your time,

    GianCarlo

     

     

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    Audyssey Labs

    Hi GianCarlo,

    We don't recommend taking measurements for people sitting on the floor.  I would keep the mic at the same height as the couch seats.

    If your couch is up against the wall then take measurements 7 and 8 about 50 cm forward from where they are shown in the diagram.

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    Henrik Lange

    Hi Chris.

    I just got my hands on a Denon 2807 amp, and I'm going to set it up later today. :)

    I have 2 quezstions about the audyssey system though.

    First of - I got this unit second hand from a guy who mispaced tho original round, flat measuring mic. I've been able to get my hands on one of the new, more "pyramid" shaped ones - will I get a good enough result using that instead?

    Second, I don't have a tripod to place the mic on. I do have a microphone stand though, but I was thinking - would it be a disaster if I where to just lay on the floor or couch or whatever and held the microphone in place with my hand, as long as I stay UNDER the mic- and not anywhere around it?

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    Audyssey Labs

    Hi Henrik,

    1. You MUST use the mic that comes with the unit.  Using the newer Audyssey mic will not give correct results because the calibration curve in the 2807 is expecting the old Denon mic.

    2. It's not ideal, but you will get OK results by holding the mic.  You may have high frequency problems because of reflections from your hand or body...

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    mecedo

    Hi. I have a question about mic. During measuring it is directed to ceil. Isn't better if mic is directed to wall with speakers? Of course then I have to reverse mic in pause when calibration changes from R channel to Surround R. High frequencies like 15kHz are very directional so if mic is directed to ceil then high frequencies after calibration are boosted by a few dB. As a result during listening music sound is hissing. If I use my method then sound is more natural. Am I right with my method?

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    Audyssey Labs

    Pointing the microphone to the speakers will give completely wrong results.  The microphone is calibrated for what is called grazing incidence and so it must point to the ceiling.  Microphones designed to point to the speakers are only useful when measuring speaker response in an anechoic test chamber.  In-room measurements require the microphone to point up and so a different calibration is used.

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    Andreas

    Hello. Yet another post about placement... For the record I'm using an Onkyo TX-NR809 (MultiEQ XT) and a KEF 3005SE system, bought just 2 weeks ago.

    My couch is placed against the back wall, and before I knew about the 18 inch rule I took a 3 point measurement exactly where my ear was placed in the couch; 5cm above the couch back, 10cm from the wall. I had to remove the pillows to be able to place the microphone as I'm using a tripod. It reported the following crossovers: F 70Hz, C 60Hz, S 90Hz (5.1 system), and I was very happy with the results watching Transformers 3 right after.

    After getting into the tech reading I found out that I'd measured wrong. Your recommendation is placing the microphone 45 cm from the wall, and giomania's (AVS forum) recommendation says 30cm minimum. I ended up taking the new measurement 35-40 cm from the wall. This time a 6-point measurement. It reported the following crossovers: F 80Hz, C90Hz, S 80Hz. I couldn't be bothered watching TF3 again, but I've watched different other movies and I have to say I'm not as happy with this result. Whether this is placebo or not I cannot know. I've taken this measurement multiple times and end up with the same configuration result.

    My main question: if Audyssey is all about room correction for the listening position, why shouldn't I measure exactly where my ear is? After all; this IS where my ear is, and not 25-30 cm forward of that position. I understand there will be reflections from the back wall, but those reflections will still be there when I sit down to watch a movie. Isn't this what Audyssey is supposed to correct for? Or will there be too many other parameters with values way off if I do this? The way my system is calibrated now, while watching a movie, my head is actually never inside the "cube" where measurements were taken.

    Side-note questions: Should I warm up the speakers/AVR before doing measurements (ie play 30 minutes of music)? Should I wait for the speakers to break in properly before I take any further measurements?

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    Audyssey Labs

    The reason not to measure so close to the wall is that the info reaching the mic in these conditions is different from the info reaching your ears.  The crossover differences reported are very small so I don't think it would be an audible change.  

    No need to warm up the speakers or wait for break in.  There are no measurable effects that would influence the results.

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    Andreas

    Ah, of course. I don't know why I didn't think about that. After all; the mic isn't shaped like my ear :)

    Thanks a lot for clearing that up for me! Regardless; Audyssey is making extreme improvements in my very awkward living room.

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    robert Carman

    Hey Chris!!

     

    I have been running Audyyseey for a year or so now and was reading thru the comments and have 1 small question.....since my seatbacks are higher than the ear level I raise the mic above the seat back wich is 4-5" above ear level....would I be better off just putting the mic at ear level and putting the mic foward a few inches (how many inches do you suggest) instead of raisng it so much? I do put towels over the set to minimize reflections.

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    Dag Johnsen

    Hi Chris,

     

    when measuring the stereo (2 channel) before and after XT32 PRO calibration with REW,

    should we place the microphone in sweetspot and run a sweep, or measure left and right separately and average them after? Do you reccomend 1/6 smoothing or 1/24 to judge the results properly.

     

    Very happy with my Denon A100 / Audyssey XT32 !!

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    Tomas Korber

    Hi Chris,

    I use the IK Multimedia ARC System that works with the Audyssey MultEQ technology. I hope you can help me out since the IK Multimedia Support couldn't provide any useful information.

    I use the system in my studio, which is an acoustically treated environment. I sit at 125-130 cm (about 50 inches) from the speakers.

    the ARC manual provides some examples of how to lay out the measurement points, but frankly i thought the examples didn't really reflect my listening situation. the points in the examples are usually very spread out and there are no height differences between the measurments point. but i sit pretty much near the sweet spot all the time, however i sit sometimes a bit higher and sometimes a bit lower. so i figured out a measurement plan that is slightly different (see attached picture), since I thought that it represented my listening position more accurately.

    Note that i took the measurement in pairs of three (1 point on the center line, one point about 4-5 inches to the left/right, one point 2-3 inches up/down), so there are as many measurements on the actual center line as to the L/R. Also, I chose to measure at different heights, since, as mentioned above, sometimes i sit a bit higher/lower in my chair. The measurement plan is absolutely symmetrical, so i figured if the Audyssey/ARC system works by taking an average value (btw: does it?) i should get a good result with this layout (it's a cube, basically).

    so my question are:

    1) generally: do you think i'll get good results (in theory) with this measurement-plan?

    2) is it ok to have this many measurements on the actual center line, or is it important to have only the first and last measuremant on the center line (as the examples in the manual show)?

    3) is it ok to use measurement-points at different heights the way i did?

    thanks for your time,

    tomas

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    Audyssey Labs

    @Robert: it's best to place the mic slightly above the seat back to avoid reflections from it.

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    Audyssey Labs

    @Dag: you should place the mic in the same locations where the Audyssey mic was.  Then collect the measurements and perform an RMS average in REW.  It will give you a pretty good idea of what MultEQ is doing.

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    Audyssey Labs

    @Tomas: yes, this is a good way to measure.  Varying the height slightly is a good idea, especially when you have more measurements to play with.  Audyssey does *not* use averaging.  The problem with averaging is that each measurement is given equal importance.  But, the acoustical problems are more serious in some spots than others so we use a non-linear way to combine the measurements based on the severity of the problems found.

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    Tomas Korber

    Chris,

    First of all: Thank you for your prompt reply and the very useful information!!

    You pretty much answered this already, but just to be 100% sure: the system finds out automatically how to weight the different measurements, right? As opposed to: the system assumes that you'll be measuring in a certain pattern, for example, that you measure in pairs of 2, one to the left, one to the right and the last measurement will be in the middle (or something along those lines)... In other words: As long as i make the first measurement in the center position and keep a symmetry with all other measurements, i'm free to define my listening area however i want to (i.e. it's OK if i have several measurements along the center line).

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    Tomas Korber

    Oh, and one last question while am at it: The manual says to have the test-tones play at your 'normal' average listening level. i find it easier to measure when playing them a bit louder (less problems with background noise... i just make sure to adjust the mic-preamps so that the microphone level is still in the OK area as required by the software). is that OK (playing test-tones at louder volume than usual music litening) or will it affect the measurment-accuracy?

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    Audyssey Labs

    Yes, Audyssey automatically combines the measurements with the appropriate weighting.  That's why the measurement order doesn't matter (after the first one that has to be in the center).  If you want to give more weighting to the center line then you are doing it correctly: take more measurements there.

    Louder levels are fine as long as you are not clipping the mic input.

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    Tomas Korber

    Chris - perfect. Thanks very much for your help with all of this. That's what i call a great customer support!! And congratulations again on a great system.

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    Alex0925

    Hey Chris,

    It's nice to be back, well, one thing just crossed my mind recently: it was my understanding that for equalizer setup Audyssey MultEQ measures the volume of the room, not the space, so, would it be correct to assume that any objects not interfering with setup mic signal flow towards speakers, but still located in the room (e.g. wall mounted shelves and other small sized built-in furniture will still cause errors in equalizer frequency response setup calculations? In other words, for the one and only correct AVR EQ frequency response setup calculation should MultEQ room correction setup be done in absolutely empty room?

     

    Sorry if I didn't make myself quite clear, happy to elaborate on that

    Many thanx in advance,

    Regards,

    Alex

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    Audyssey Labs

    Hi Alex,

    The purpose of measuring is to find out what the room is doing when you are listening.  So, it should definitely not be empty!  If there is a problem from shelves or other things in the room the measurement needs to know about it.  Otherwise it will correct for conditions different than what will be there during listening and that would not be very useful...

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    Alex0925

    Thanx, Chris, that makes sense to me, I just wanted to make sure that small pieces of furniture not obstructing the mic signal line do not cause incorrect measurement and setup of Audyssey EQ, and specifically, do not result in unnecessary bass cut, as was the case with placing the mic within 50cm range from walls.

    Many thanx for your clarification!

    Merry X-mas and a Happy New Year to you!

    Regards,

    Alex

     

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    CÜNEYT OCAKLILAR

    Hello,

    My listening position is too close to my back wall because my sofa is placed just front of the back wall. So, I am in concern that the auido signals reflected from the back wall into the mic would effect the result of the calibration.

    First, when I used MCACC for the calibrartion with this situation, the result was terrible. When I put the mic a little far away from the wall, the result was a little bit better than terrible. Then I tried the first situation (while the mic was too close the wall)  with Audyssey (from 6 points), and the result was very good. I wonder whether it would be better or not to hang something (e.g. a blanket) on the wall while calibration?

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    Audyssey Labs

    Hi,

    A blanket has no effect at all on the bass frequencies that build up near the wall.  So, it won't make any difference to the measurement.  I would suggest leaving the system as you have it now: if you have good results why change them? :-)

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    CÜNEYT OCAKLILAR

    Thanks Chris, suggestion accepted. :)

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    Jason Johnson

    I purchased a Denon AVR 3311ci last week and I kind of got ahead of myself and I connected the Audyssey MIC and did a setup but it wasn't where I sit. It was in the middle of the room. Is there anyway I can reset the Audyssey settings and start over?

    Thanks,

    Jason

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    CÜNEYT OCAKLILAR

    You can start over any time. Turn your TV and AVR on and insert the mic.

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    Jason Johnson

    That's easy enough. Thanks.

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    Owen Heuston

    Hi Chris,

    Why would Audyssey set my Acoustic Research AR2C Center at -6 on my Onkyo SR-608?  It is not too close to any wall or corner. 

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