TX-SR805 Measurements

Video Testing: Audioholics/HQV Bench Testing Summary of Test Results

Perfect Score is: 130
Onkyo TX-SR805 Benchmark Score: 63

Source component was the Toshiba D-KR2 DVD Recorder (480i - component video) deinterlaced to 480p via the TX-SR805 and displayed on a Mitsubishi WD-65733 Display.

The Onkyo receiver posted an average score on these tests when compared to many current displays and source components. However, it completely misses on film detail and 3:2 cadence tests.

Audio Testing

Measurements were performed using the Sample Champion program developed by Paolo Guidorzi of Purebits. The program is a Maximum Length Sequence (MLS) program that generates an impulse response in the time domain from this pseudorandom signal. Fast Fourier Transformation is applied to the impulse response to generate the system frequency response. The operating principle is the same as that of the well known MLSSA program.

Test samples were taken using 16 bit resolution with a 48 kHz sampling frequency. Fast Fourier Transformations were performed at 64K allowing for a frequency resolution of .73 Hz, which is more refined than even 1/24^th octave resolution at the lowest octave; the A0 key on the piano has a fundamental frequency of 27.5 Hz.

In room acoustic testing of the TX-SR805 was performed both with and without Audyssey MultiEQ XT engaged for comparison. Audyssey acoustic calibration was generated using eight microphone measurements located at both primary and secondary listening positions as well as throughout the listening area.

Test measurements were then performed at the primary and secondary listening positions for both the left and right main channels at an SPL of 80dB at each listening position. The primary listening position is located approximately centered on the front L/C/R channels and at the approximate center of all calibration settings for time delay. The secondary measurement position is located to the left and forward of the primary position near the room boundary.

Comparisons of the in room frequency response results without and with Audyssey engaged are presented in two forms. First, a high frequency resolution overlay plot in logarithmic scale of both conditions is provided. The second form is a side by side comparison of frequency response without and with Audyssey engaged plotted at 1/3 octave bands. The 1/3 octave band plots consider the commonly accepted limits of human hearing to differentiate relative frequency variation and thus are more representative of the changes one might actually hear.

Figure 1: Overlay of front left channel at primary position with/without Audyssey

Figure 2: Overlay of front left channel at secondary position with/without Audyssey

Figure 3: Overlay of front right channel at primary position with/without Audyssey

Figure 4: Overlay of front right channel at secondary position with/without Audyssey

Figures 1 through 4 show the high resolution plots for each measurement position and speaker. Typically, all the plots show correction in the high frequency range where room absorption pulled the curve below the Audyssey calibration curve. We also see a general flattening out of response through the midrange and into the bass regions. The most dramatic change is in the left channel at the secondary position, also at the left of the room, where Audyssey made attempt to adjust the curve for room boundary gain in the bass region and balance it with the midrange and treble. It is here that we also see the greatest treble roll off correction.

Figure 5: 1/3 Octave frequency response without and with Audyssey of the left front channel at the primary position

Figure 6: 1/3 Octave frequency response without and with Audyssey of the left front channel at the secondary position

Figure 7: 1/3 Octave frequency response without and with Audyssey of the right front channel at the primary position

Figure 8: 1/3 Octave frequency response without and with Audyssey of the right front channel at the secondary position

The frequency response curves in Figures 5 through 8, plotted in 1/3 octave bands, show the changes without Audyssey engaged and with Audyssey engaged, respectively, for each channel and at each listening position. From these plots, the general smoothing trend with Audyssey applied can be more easily discerned. General changes in curve shape are consistent with the previous observations from the high resolution plots.

One additional item to note when using Audyssey, because it also corrects phase errors, frequency response alone will not tell the whole story. Flattened frequency response is responsible for some of the improved perception of more balanced and fuller sound, but it is the improvements in phase coherency that lead to improved imaging, focus, and envelopment in the surround sound field.