How to Setup and Optimize Sound Quality using OE Equalizer

tadda

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I thought this might be useful for those interested in how to set up the sound system equalizer to optimize sound quality...The EQ setup and results shown in this thread were done after implementing some much needed design improvements to OE Subwoofer System...

How to Improve OE Subwoofer Quality and Eliminate Vibrations

There are actually a few variables / steps that need to be considered when making EQ adjustments...
  • Ear / Hearing Response
  • Sound Space / Environment
  • Psychoacoustic Effects (Understanding Equal Loudness Perceptions)
  • Personal Music and Sound Preferences
Items Required:
Below are the steps that were taken to setup audio system EQ...

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1 - My hearing response curve was measured using a Hearing Test app and considered just for reference:

hearing-test-jpg.jpg


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2 - Equal loudness curves (loudness perception) need to be taken into consideration...Equal-loudness contours describe the perceived loudness of a sound in relation to its frequency for human listeners...The ear is not equally sensitive to all frequencies, particularly in the low and high frequency ranges.

Further explanation of equal loudness / psychoacoustic effects linked below:

Psychoacoustics - How We hear


fm-curves-revised-jpg.jpg


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3 - Initial analyzer test results are measured with a smart phone using Sound Analyzer App and pink noise reference .wav file played through the sound system...I also use a higher quality external Omindirectional Microphone rather than using the phones built in directional mic...(Remember to turn off all sound effect / enhancements within the smart phone such as dolby atmos, adaptive sound, and set phone EQ to normal or flat)...

The OE audio equalizer (along with broad bass and treble) should be set to a flat / "0" response at a prefered listening volume...No adjustments are made at this point...

This test identifies all the peaks, dips, and nulls in the sound environment that will need to be compensated for...


1c-weighting-flat-eq-settings-jpg.jpg


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4 - Final analyzer test results are measured with RTA analyzer app using pink noise reference .wav file and adjustments to the curve are then made to EQ settings using a JBL House Curve as a reference....Again, this was done again at prefered listening volume...

eq-adjust-with-new-mic-1-jpg.jpg


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5 - The Harman house curve (below) is taken into consideration when making the final EQ curve adjustments...

Why a house curve? When you have flattened out the analyzer’s display curve and corrected all the dips and nulls, you’re still not done with the EQ adjustments. If you play music through your system at this point, you probably won't be very pleased with the results. You also have to compensate for other variables as mentioned earlier which includes a very important psychoacoustic effect (see Fletcher Munson equal loudness curves).. In short, a flat response will not sound so great to most people...

Tip: The broad bass and treble settings are adjusted last after corrections / changes are made to the curve using the 7 individual EQ frequency settings...

harman-target-house-curve-jpg.jpg


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6 - Here are my final EQ settings after taking all variables (environment, hearing, psychoacoustic effects, and preferences) into account...

equalizer-settings-after-sound-test-jpg.jpg


And here are my current audio settings*:
  • ASD / Active Sound Design (off)
  • Surround (off)
  • Speed Volume (0)
  • Balance: (0)
  • Fade: (front +2)
  • Broad Bass (+2)
  • Broad Treble (-2)
I found that selecting the "Surround" enhancement feature added to the phase distortion which resulted in reduced sound clarity...This is one of the first things I turned off and the system clarity was noticeably improved...Also note that "Speed Volume" is turned all the way down as this will change the EQ curve as speed increases resulting in an undesirable response at hwy speeds...

*Note that these are my new settings after I did some some much needed improvements to current OE Subwoofer system...

How to Improve OE Subwoofer Quality and Eliminate Vibrations




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tadda

tadda

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To Summarize...

Here are final results using a different Real Time Analyzer App which shows the Supras' audio system frequency response from the drivers seat and where the Equalizer needed to be adjusted to in order to achieve these results...I was very pleased to see how uniform the frequency distribution is within the Supra's cabin and how relatively easy it was to smooth out any peaks, dips, or nulls and make adjustments using the Equalizer....Obviously the system is not lacking in low bass response...


EQ adjust with new mic 2a.jpg


Equalizer settings after sound test.jpg
 
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Half Vast

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Gotta ask (you may have answered it somewhere already), are you an Audio Engineer by trade or just a damn knowledgeable audiophile? No disrespect intended. Just asking since you have taken a precise and detailed approach to derive this info.

Nicely done!
 
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tadda

tadda

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Gotta ask (you may have answered it somewhere already), are you an Audio Engineer by trade or just a damn knowledgeable audiophile? No disrespect intended. Just asking since you have taken a precise and detailed approach to derive this info.

Nicely done!
Ha! No worries...and thanks!

Yes, I am a retired Engineering Exec (telecommunication systems) and have enjoyed Audio design as an interest / hobby over the years...As an Engineer I kinda enjoy identifying and solving problems and improving on existing designs...
 

Half Vast

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Yes, I am a retired Engineering Exec (telecommunication systems)....
I retired from the telecom industry as well. I was a Senior Engineer for Verizon Wireless. One of my hobbies is restoring vintage audio equipment. Recently restored a Yamaha M80 amplifier and some Magna-Planar speakers, but my favorite to restore is anything by Carver.

Anyway, thanks for posting this stuff. I like the approach.
 

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