I recently purchased a Marantz receiver with Audyssey MultEQ built-in. I thought it would be interesting to compare the results from manually setting up this receiver using professional tools to Audyssey since it is so popular.
Observations And Comments
My general impression of the setup that resulted from running Audyssey was that it sounded harsh in comparison to the manual calibration which sounded natural when listening to normal program material. This reminds me of many comments I hear and read about people’s home theater systems sounding harsh. I suspect many of these problems could be removed by setting up the preamp or receiver properly using a manual method.
Audyssey missed the phase (wiring) of both the front speakers and the center speaker. This is very troubling. That type of error will cause a loss of bass at the crossover and will result in speakers not integrating well at the higher frequencies as well. These speakers combine to form a system and each must be in phase with the others to work together properly. I have found that this is not an uncommon thing to find in systems that were setup with automated audio calibration systems. Unfortunately, it is important that you have some method to determine what the absolute phase of your speakers and subwoofers really are. I find a very high percentage of speaker and subwoofer products are shipped with the red and the black terminals or the 0 degree phase setting being incorrect.
The differences in channel distances from the manual and automatic calibration were not great enough to alter the results dramatically. However, I have seen cases where Audyssey misses phase and will then have radically incorrect distances for the subwoofer.
Channel levels from Audyssey did not come close to reference levels at 0 db on the volume control. The error was -5.5db for the center channel which is the reference channel for movies since it is the source of dialog. 5.5 db louder requires 260% more power to the speakers.
I am sure if I provided Audyssey with the two subwoofers not setup properly it would have been easy to obtain very poor results for the LFE channel and bass management. The increased error in the frequency response from Audyssey is disappointing since it degraded the subwoofer performance from what it would have been without any equalization being applied in the receiver.
It should also be noted that these automated receiver setup systems will do nothing to fix a vast array of problems that are external to the receiver. These problems include room acoustics, speaker/subwoofer placement, subwoofer settings, failed drivers, loose connections, loose components, poor wiring and rattles. These issues are just as important as the settings in the receiver, but are frequently missed without careful attention to the system. For this test all of these problems were solved for the receiver, but in the average home they may not be.
Main Speakers: Hales Revelation 3 (three way with a 10″ woofer)
Center Speaker: McIntosh CS350 (three way with two 6.5″ woofers)
Surrounds: Klipsch RS42 (two way with two 4″ woofers)
Subwoofers: Revel B15 (15″ driver) and James Audio EMB-1000 (10″ driver)
Receiver: Marantz NR1402 (not normally in this system)
The room is acoustically treated to around 230ms RT60 at 500Hz with six seats. All of the speakers were positioned and wired properly before the test started. All seating positions in the room were measured with Audyssey. The primary seat was measured as the primary in Audyssey and used for the manual calibration and comparisons. Both subwoofers were originally set manually and are equalized and balanced independently of the receiver. No settings were altered on the subwoofers between Audyssey and the manual receiver adjustments. All Audyssey measurements were made at 0 db to avoid issues with level based equalization altering the results.
Speaker Phase Results
Audyssey detected both of the front and the center speakers as being out of phase. All of the results from Audyssey were conducted with the phase of these speakers swapped as indicated by Audyssey. Manual adjustment and an absolute phase meter showed Audyssey’s request to change the phase of these speakers was wrong. The manual calibration was done with the front three speakers in phase instead of 180 degrees out of phase as set by Audyssey.
Speaker Size Results
Audyssey set the front speaker to large and all others to small. Manually all speakers were set to small. Audyssey not crossing over the low frequencies to the subwoofer for the front channels increased distortion and resulted in less low frequency output for the front channels. It also did not take advantage of the substantial power savings on the receiver by using the amplifiers in the subwoofers for the front speakers instead of the receiver.
Bass Setting Results
Subwoofer Mode was set to LFE and the LPF for LFE was set to 120Hz for both Audyssey and manually. These are the proper settings for these parameters in this system.
Left Front 9.5ft 9.4ft
Front Right 9.3ft 9.1ft
Center 8.8ft 8.4ft
Subwoofer 9.3ft 8.0ft
Surround L 8.6ft 8.9ft
Surround R 8.3ft 8.0ft
Channel Level Results
With the receiver set at 0 db the output volume level from the speakers should be at reference level. The following table shows the deviation for each channel as measured by my reference microphone and preamp. This measurement was made using the Goldline Audio Toolkit disc limited bandwidth pink noise which is very accurate. The data shows the channels were all low and error from the correct level at the prime seat was as much as 2.0 db from the center channel signal where dialog sets the reference. A 2 db increase in sound requires 60% more power to the speakers. The channel imbalance could easily be the result of averaging multiple seats and may be desirable if the goal is to more evenly balance the levels in the theater, but it will not be the best setup for the prime seat.
Error Measured From Prime Seat
Front L -5.0 db
Front R -3.0db
Surround R -4.2db
Surround L -4.7db
Crossover Frequency Results
The crossovers were set to 80Hz for the center and surround speakers by Audyssey. Manually the crossover for the center and surrounds were set to 80Hz while the front channel was set to 40Hz. Audyssey not crossing over the low frequencies to the subwoofer for the front channels increased distortion and resulted in less low frequency output for the front channels.
When Audyssey was complete the MultEQ was set to Audyssey, Dynamic EQ On, Reference Offset 0db and Dynamic Volume to off.
The following data shows how the LFE channel equalization was not as flat at the primary seat as the system was without Audyssey engaged. The subwoofers had previously been optimized and equalized and this was left in place for Audyssey. The nominal level of the LFE signal without Audyssey deviated significantly more between 50Hz and 60Hz than without Audyssey.
The average frequency response as measured using the Avia five channel pink noise signal showed that the average frequency response with manual equalization was also superior to Audyssey.