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Experiment: Level Matching Frequencies

For fun, from my listening position, I experimented with a Radio Shack SPL meter and a demo disc. Using the ROON equalizer, I level matched frequencies at 80dB (50Hz, 63Hz, 80Hz, 100Hz, 125Hz…etc.) This took a few hours and the results were not good.

Of interest, I corrected a peak of +12dB @ 80Hz, a dip of -8dB @ 100Hz,  and a peak of +6dB between 160-200Hz. Other frequencies up to 10kHz needed minor adjustment of +/- 1 to 3dB.

With adjustments, music sounded terrible. For example it was very thin in the mids, compared to no EQ. This experiment was a waste; I expected and hoped these adjustments would improve the sound. Please note: I am a recreational listener, not and EE nor majored in music which means this experiment was ad hoc and  unscientific.

Have any of you tried this or have thoughts as to why level matching frequencies this way had poor results?

4hannons
erik_squires
5,268 posts
 
Um, don’t do that. :)

First, if you need a good, cheap calibrated mic, use the Dayton imm-6. The RS SPL meter is severly constrained at both ends.


https://amzn.to/2Ly6G65


If you have an Android, Audio Tools works perfectly.

If you have a new iPhone you will need an adapter and I don’t know what software.

Next, flat is not actually ideal. A descending frequency range from around 100Hz is. Among others, look for the Bruel & Kjaer ideal speaker curves, or look at the documentation for something like Dirac. Whether you like Dirac or whatever, it shows a descending, not flat curve.

There is a lot written on why a flat EQ is not actually desirable in a room, that’s what Google / Bing / DuckDuckGo are for, but we use flat for anechoic, and quasi-anechoic measurements. That's why you'll see those terms in a lot of speaker measurements in reviews.
gdnrbob
2,421 posts
 
Eric, I recall that you build speakers. Right?
Do you think my assessment regarding crossover/wiring affecting hound level balancing correct?
Bob
elizabeth
6,726 posts
 
IT is true, plenty of cheap microphones have far far worse frequency response than speakers!
erik_squires
5,268 posts
 
@gdnrbob2
Not really, assuming you have a decent SS amplifier and reasonable speakers, the crossover and EQ won't interact very much, but your point that EQ should be used sparingly is not wrong.

Using EQ well is an art. In the bass, you want surgical precision. In the midrange and treble  you want to be delicate.

You can only adjust a speaker so far, and the idea of using an EQ to make up for it's deficiencies never works out well. What EQ does well is in the mastering process, or to help correct for certain room problems.

Also, using them as tone controls, with grouped, and gentle adjustment is a good thing.

Best,
E
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