Measurements, EQ, and what we actually hear

[James]

That is an incorrect statement.




Test tones are, in fact, sine-waves, what frequency test-tones are you using?

Please elaborate on the first statement, if you don't mind.

Yes, but it's not a sweep - the test tones go from a low c (32.7 Hz), in 1/12 octave steps, up to the c at 4186.01 Hz. So it's a chromatic scale that goes up to and a bit beyond the top note on a violin.

It leaves out the upper octaves, but I don't hear much in the top octave or two.

[James]

James,

The background of my entire career in this industry is to try and correlate what we hear with measurements, and I am still not there - nor do I suspect this industry will ever be. We all hear differently and the biggest mistake one can make is to trust one's own hearing.

As measurement technology improves, so does our ability to at least make an estimate as to what we can expect to hear. Your method of using sine-wave test tones combined with an SPL meter to try and determine how a speaker measures (ie sounds like) is very flawed, and a method that was thrown away over 30 years ago.

First off, sine wave test tones excite only a specific frequency, so unless you are able to run 1/12th octave test tones (12 test tones per each octave), your data is basically not usable.

Second, sine wave test tones are steady state signals, they are not music and can actually be quite damaging to a speaker (especially a ribbon tweeter)

Third, with using your SPL meter to measure ( I assume this is actually a calibrated spl meter, hopefully not an app on a mobile device) - the only thing you are somewhat accurately measuring is the acoustics of your room (and even that is questionable), not the speakers. (this is why this method was thrown in the dumpster so long ago)

And finally, and I must stress this - please do not trust your hearing to even attempt to estimate an actual frequency response measurement. There is nothing more inaccurate than your own hearing and it will take you many, many years of critical listening experience combined with understanding how to take accurate measurements and understanding of the differences between an in-room response and an anechoic response.

My advice to you, throw out all of your current assumptions regarding audio measurements, read as much as you can about using REW (it is a good place to start) and most importantly - about how to interpret those measurements.

Hope this helps!

Well, then I'm not off-base with my questions/uncertainty about the topic - that's good to know.

I do use 1/12 octave steps, and I don't use an SPL - I just listen to the tones.

The idea that I shouldn't trust my own hearing is hard for me to accept somehow. I mean, I understand from hearing tests that I've lost some in the top region, and accept that - I wouldn't claim that I hear what's going on up there.

And when my wife hears more than I do down in the 30-40 Hz region, I believe her. But thinking that within my limits, I'm not hearing what's there is harder for me.

[davef]

Please elaborate on the first statement, if you don't mind.

Yes, but it's not a sweep - the test tones go from a low c (32.7 Hz), in 1/12 octave steps, up to the c at 4186.01 Hz. So it's a chromatic scale that goes up to and a bit beyond the top note on a violin.

It leaves out the upper octaves, but I don't hear much in the top octave or two.

James, a sine wave is not a sweep. A single frequency, steady state sound-wave, by definition, is a sine wave.

James, please don't take this as anything but constructive, I can see you have tremendous interest in this subject, but you do have much to learn, I suggest you purchase some books on audio measurements to get the basics.

[davef]

The idea that I shouldn't trust my own hearing is hard for me to accept somehow. I mean, I understand from hearing tests that I've lost some in the top region, and accept that - I wouldn't claim that I hear what's going on up there.

Are you assuming that you hear every frequency evenly? Are you assuming you have absolutely perfect hearing? I don't mean able to hear from 20Hz to 20kHz, but that you hear each frequency the same as another frequency? You are doing yourself a tremendous disservice to make that assumption.

The shape of your ears, the shape of your ear canals, including a dozen other factors unique to you determine the frequency response of your own hearing.

In addition, human hearing also changes with volume... Please research the Fletcher Munson curve.

Trying to determine the frequency response of a speaker, any speaker, by simply listening to steady state waves is no different than trying to determine how something tastes by simply looking at the ingredients. Even trained critical listeners and/or experienced musicians could not even attempt to do so.

[Pogre]

James,

The background of my entire career in this industry is to try and correlate what we hear with measurements, and I am still not there - nor do I suspect this industry will ever be. We all hear differently and the biggest mistake one can make is to trust one's own hearing.

As measurement technology improves, so does our ability to at least make an estimate as to what we can expect to hear. Your method of using sine-wave test tones combined with an SPL meter to try and determine how a speaker measures (ie sounds like) is very flawed, and a method that was thrown away over 30 years ago.

First off, sine wave test tones excite only a specific frequency, so unless you are able to run 1/12th octave test tones (12 test tones per each octave), your data is basically not usable.

Second, sine wave test tones are steady state signals, they are not music and can actually be quite damaging to a speaker (especially a ribbon tweeter)

Third, with using your SPL meter to measure ( I assume this is actually a calibrated spl meter, hopefully not an app on a mobile device) - the only thing you are somewhat accurately measuring is the acoustics of your room (and even that is questionable), not the speakers. (this is why this method was thrown in the dumpster so long ago)

And finally, and I must stress this - please do not trust your hearing to even attempt to estimate an actual frequency response measurement. There is nothing more inaccurate than your own hearing and it will take you many, many years of critical listening experience combined with understanding how to take accurate measurements and understanding of the differences between an in-room response and an anechoic response.

My advice to you, throw out all of your current assumptions regarding audio measurements, read as much as you can about using REW (it is a good place to start) and most importantly - about how to interpret those measurements.

Hope this helps!

Absolutely so well put Dave! Every time I see someone talk about testing their speakers with test tones and their ears, in room, I die a little bit inside... lol.

[James]

Well, I did a bunch of thinking and researching on this before looking at the thread again, and it's clearly a very complex subject. And I often find that with interesting subjects, the more you learn, the more questions you have.

If it were possible, I'd buy an equalizer, mic and REW software, learn how to use it, and see what results I get. Unfortunately, that's not possible right now. Also, it turns out that REW software doesn't work with an I-Pad, which is the only laptop we have.

As soon as it's feasible, I'll try to pick up the Behringer - that can be plugged in and used right away. And I can manually adjust things until I like the results, which should be gratifying even if they're not perfect/correct.

Of course, I'll be extremely curious about how measurements would look, and how that would compare with what I hear. At some point, I may be able to justify more of an investment. One nice thing about the Behringer equalizer is that it can work with REW - of course there would be a lot to learn about that.

I'm still interested in anything people want to share about their experiences with REW, and how what they see with the measurements does or doesn't correlate with what they hear.

[James]

If anybody's interested, I have found and used a very cool site where you can test various things, including different aspects of your hearing:

Free Online Audio Tests, Test Tones and Tone Generators (audiocheck.net)

If you like this sort of thing (and have time), it's a lot of fun. And I find that doing the tests can improve one's ability to hear different things, like timing differences.

[James]

Are you assuming that you hear every frequency evenly? Are you assuming you have absolutely perfect hearing? I don't mean able to hear from 20Hz to 20kHz, but that you hear each frequency the same as another frequency? You are doing yourself a tremendous disservice to make that assumption.

The shape of your ears, the shape of your ear canals, including a dozen other factors unique to you determine the frequency response of your own hearing.

In addition, human hearing also changes with volume... Please research the Fletcher Munson curve.

Trying to determine the frequency response of a speaker, any speaker, by simply listening to steady state waves is no different than trying to determine how something tastes by simply looking at the ingredients. Even trained critical listeners and/or experienced musicians could not even attempt to do so.

Thanks for the response - those are good points.

I knew, but forgot about the Fletcher Munson curve - that definitely would point towards boosting the bass a bit, especially at lower volumes.

[curtis]

James,

RE: "I'd buy an equalizer"

I highly suggest before you do that, you understand what is going on in your room and your ears.

Also, all your equipment is full analog, all that Behringer stuff runs in the digital domain, so it sends the signal through a ADA cycle, which can also harm the sound. It is the reason why most people use the Behringers to EQ just their subs/bass.

I suggest going out and listening to different setups, speakers, rooms, etc and what your perceptions are for everyone one of them. Get some experience just listening.

BTW, I have heard a speaker, with the same enclosure and drivers, but with two different crossovers. Their FR graphs was very similar, but they sounded very different. Very eye (ear) opening. It cracks me up when people ask about a speaker's internal crossover point.

[curtis]

If anybody's interested, I have found and used a very cool site where you can test various things, including different aspects of your hearing:

Free Online Audio Tests, Test Tones and Tone Generators (audiocheck.net)

If you like this sort of thing (and have time), it's a lot of fun. And I find that doing the tests can improve one's ability to hear different things, like timing differences.

The problem with that is you assume the playback equipment you are using has accurate reproduction and is calibrated.