YPAO & PEQ Measurements and Analysis

All of the following measurements were conducted using 1/12th octave FFT analysis. I measured the effectiveness of YPAO's integrated PEQ in all of its settings for the front channels at the listening position as well as how it affected bass response, and center channel to front channel tonal matching.

Mid, Low, Flat and High PEQ Settings for YPAO

Front PEQ Setting for YPAO

With no equalization applied, you can see that the center channel of my system (which is basically a horizontally placed version of my main system speakers (without the subwoofers), measured similarly to the summed response of my main speakers at the listening position. This measurement was taken with the RX-Z9 engaged in "Prologic IIx" mode for the center channel measurement, and "2 Channel" mode for the Front channel measurement.

Flat Setting:

Flat yielded an EQ result very similar to no PEQ at all for my set-up. It inserted a slight bump of +3dB from 100-125Hz and helped to reduce a narrow null centered around 160Hz. Aside from a +4dB bump added by the PEQ at 315Hz, most of the upper end of the frequency spectrum was unaltered. This partly explained why I was hearing a slightly fuller sound in the mid bass region.

Low Setting:

From 56Hz-80Hz PEQ reduced a bass bump by about 4dB. As with the "Flat" setting, it inserted a slight bump of +3dB from 100-125Hz and helped to reduce a narrow null centered around 160Hz. A similar +4dB bump was added by the PEQ at 315Hz. PEQ smoothed out a slight null from 1700Hz to 2100Hz by adding a +4dB boost. PEQ added an unnecessary +4dB of gain from 8kHz to 11.8kHz. PEQ did improve frequency extension by adding +3-5dB of gain from 16kHz to 20kHz, extending the 3dB point of my system from the listening position from about 18-20kHz. This was my favorite sounding setting for PEQ.

Mid Setting:

PEQ gave a rather ragged response from 265Hz-760Hz. However, it also inserted a slight bump of +3dB from 100-125Hz and helped to reduce a narrow null centered around 160Hz. PEQ squashed the lower treble by -5dB from 12kHz-17kHz. This setting was too forward sounding with too much emphasis on upper bass, yielding a very chesty sound in male vocals.

High Setting:

The high setting almost mimicked the flat setting up until about 5.6kHz. It added +5dB bump from 5.6kHz to 8kHz and 11kHz to 15kHz while also extended the 3dB point of the system as in the Low setting. This setting was too lispy, bright and almost compressed sounding.

Front Setting:

The PEQ "Front" settings purpose is to tonally match all speakers to the un-equalized front speakers. It appeared to do fairly well from about 170Hz to 2.2kHz, but caused a sharp roll off above 7kHz that was clearly measurable and audible in my listening tests. In fact, the center channel output vs the summed front speakers was now too low by almost 10dB from 9.4kHz to 12kHz.

A Note About the YPAO Measurements
It is important to note that some of the graphs in these measurements for the same PEQ settings varied slightly because they were recorded at separate sessions where the microphone position may have been slightly different, or the PEQ Auto measurement resulted in a different overall response. These measurements only illustrate frequency domain effects and are not fully representative of all of the variables attributed to the sonic differences between PEQ and no PEQ.

Low PEQ Setting On/Off Axis Comparison

I was curious to see how my favorite PEQ setting, "Low", would transform the sound of my front speakers when measuring their response far off axis from where the microphone actually took the initial measurement to derive its settings. I was pleased to find that the PEQ did not butcher the frequency response in location measured away from the initial calibration. In fact it did improve a bass null by +5dB in the 70Hz to 80Hz region.

Low Frequency Comparison of Manual vs YPAO

By allowing YPAO to do my entire configuration, it did not provide the smoothest transition between the huge bass bump of my primary room mode. I was able to manually tweak phase and level of my two subwoofers to add a bump from 54Hz to about 75Hz to provide a more uniform and pleasing sounding system bass response.