Audyssey Pro EQ Micing the System

Microphone Calibration Position Summary

Note mic pre-amp and in-line power supply on end table. All other microphone positions were around different areas on, standing behind, and leaning forward on the sofa. My leftmost regular seated position on the sofa was run twice. My wife's rightmost normal sofa viewing position (toward camera) was also mic'ed twice. This double-mic'ing for data acquisition gives a higher weighting to the two most often used listening/viewing positions. Moving the microphone just a couple of inches within these two "weighted measurement" locations should give MultEQ Pro good, more diverse data in these most important areas.

• Mic position 1: The center of sofa, mic 35" H, one data set/8 ch.
• Mic position 2: My left side of sofa seat, mic 35" H, two data sets/8 ch.
• Mic position 3: My 5' tall wife's 30" H right sofa seat; two data sets/8 ch.
• Note: This position is below the level of the sofa back so the rear surround channel would theoretically have to boost its SPL level a bit on these two data acquisition runs.
• Mic positions 4, 5 & 6: One data set/8 ch. each was run at the left and right sofa arms. The height here is 24". I placed the pillows we often use on the sofa's arms when we both lay down across the couch and watch a movie. The first two positions form the outer width-wise perimeter of this oblong acoustic bubble. A third 24" H data set/8 ch. was made to the right-center of the sofa to simulate when I'm sitting up watching the movie and my wife puts her head on a pillow on my leg.
• Mic positions 7 & 8: One data set/8 ch. each were made at 30" height and 7 feet from the L/C/Rs at left-center and right-center front of the sofa. These two positions form the front portion of this oblong acoustic bubble and simulate unbelieving audiophiles leaning forward as they always seem to do at the same time their jaws are dropping.
• Mic positions 9 & 10: The last two data sets/8 ch. runs are at 66" height and 1 foot behind the left-center and right-center of the sofa. These two positions simulate the casual unbelievers who don't want to have to sit down to enjoy startlingly good sound.

Once all 12 sets of data had been collected at the ten mic positions I clicked the Calculate Filters box and the Audyssey Sound Equalizer's MultEQ Pro program started crunching away. Three minutes later - ta daaa!! The Detection Results screen displayed:

• 50Hz for Left Front: Beta 10 is rear ported and placed almost against wall.
  
• 40Hz for Center: Beta 10 is rear ported and working into a corner 2.5' behind.
  
• 70Hz for Right Front; Beta 10 is rear ported and port blows into one very porous Roman shade then a second fairly closed-surface window shade.
  
• 60Hz Right Surround; Two JBL 5.25" two-ways mounted at 90° opposing angles with the corner of the angles facing the listening area and woofers close to ceiling.
  
• Large for Left/Right Rear Surround: Two JBL 5.25" two-ways mounted at 90° included angle and inside corner facing listening area and woofers close to ceiling.
  
• 50Hz for Left Surround; Two JBL 5.25" two-ways mounted at 90° included angle to listening area with woofers close to ceiling.

Deciding Crossover Frequencies

Transferring Detection Results Parameters Into Your Customer's Pre-Pro

For each surround speaker in your room the Detection Results page will give Distance, Polarity (which you've already corrected or confirmed), Trim in dB and lowest recommended crossover frequency. I transferred All Distance and Trim settings over to the Denon AVR-3806 and set Subwoofer(s) low pass to 80Hz and all satellite high passes to 80Hz. Note that I averaged the two subwoofer distances to the listening position and entered a single number.

Note: This Denon allows +6dB maximum level gain, in 0.5dB increments, to be input into any channel. However, the Audyssey Sound Equalizer will likely read out trim differences which are larger. The trick here is to understand that the Sound Equalizer figures are TRIM or negative values from a 0dB reference.

Remember that I had to add +9-10dB of gain at the DVD input level screen? Well this is also a part of why that gain had to be added. If we now use the +6dB as the maximum gain of the pre-pro go to the Sound Equalizer's screen and SUBTRACT from the +6dB starting with the highest amount of trim called out for any channel. Here are the figures I entered into the AVR-3806 pre-pro: (starting with the highest trim number)

• L/R rear surround trim= -11.5dB Audyssey. If +6dB on Denon ref. 0dB then set -5.5dB
  
• Left surround trim= -11.1dB Audyssey. If +6dB on Denon ref. 0dB then set -5.0dB
  
• Right surround trim= -10.4dB Audyssey If +6dB on Denon ref. 0dB then set -4.5dB
  
• 2 Sub average trim= -10dB Audyssey. If+6dB on Denon ref. 0dB then set -4dB
  
• Left & Right Front trims= -5.4dB Audyssey. If +6dB on Denon ref. 0dB then set +0.5dB
  
• Center trim= -5dB Audyssey. If =6dB on Denon ref. 0dB then set +1.0dB

Make sure that the 3806's internal MultEQ XT correction is off (Audyssey, Flat, and Front de-selected). Also deselect the internal Cinema EQ high frequency filter in preparation for a first listen. You or your customer can always turn the Cinema EQ filter on if that first listen tells you there is still too much high frequency energy content.

Hint: If you choose to completely finish the MultEQ Pro programming procedure before going back to the Denon to transfer setting, it's a good idea to print out (if possible) or write out all settings on a piece of paper. Then you can completely disconnect your computer and USB and disconnect the microphone phone cord from input #1. As a final step remember to plug the appropriate input RCA back into the #1 analog input on the Sound Equalizer.

The second-to-last MultEQ Pro screen is the Target Sound Options page. Four curves are given, showing flat and three degrees of various high frequency roll-offs. There is a radio button by each curve. So, based on the dimensional information you entered back on the Room Dimensions page and your experience with other installations select the Target Sound Option you believe will work best bearing in mind room size and the probable amount of passive sound absorption and diffusion the client's room will provide to aid the Sound Equalizer in performing optimally. (Reverberation chamber-like rooms need not apply.)

In my particular 21' x 25' x 8' room I selected the High Frequency Roll Off 1 curve. I later also turned the Denon's Cinema EQ back on because the sound could get a bit too bright sounding on-less-than-well-recorded sound tracks. And when it comes to this point in my installations I always try to err on the side of what the woman client would prefer. They usually prefer very slightly less high frequencies rather than hear a sound track which is annoying and screechy from being poorly recorded. Eliminate nuisance call backs if at all possible.

Lastly, I went to the Save Results program screen which let me transfer the settings from my computer to the Sound Equalizer. A mouse click on "Transfer to Sound EQ" does the trick. It's imperative to "Save Permanently to EQ" though because if the customer's system experiences a power outage or the power-on rocker switch on the back of the Audyssey is switched off the settings will be lost.

If you still haven't entered the distance, dB and crossover settings from the Detection Results screen to the pre-pro, now's the time.