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Question about EQing speakers above 500 Hz

heboil

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Hi everyone and happy holidays!

I know people ask the question and there is some debate back and forth about EQ'ing/room correction over 500 Hz. From everything I have read (which likely isn't even scratching the surface), it seems like more people believe we shouldn't EQ above 500 Hz. Okay... fair enough. But, here is where the conundrum or head-scratcher comes into play. We all come to ASR for Amir's reviews and everyone here pretty much loves Erin's reviews. I often see them reference applying correction to a speaker above 500 Hz to rectify a given problem.

So, those corrections are above 500 Hz. That is the heart of my question. Do Amir and Erin believe in applying correction above 500 Hz? Or do they only believe in correcting the "anechoic measurement"? Either way, you are still correcting above 500 Hz in the room. What if your room interaction with the "problem area" self-corrected it? If the room enhances the problem, would the correction make it better or worse? Again, this is now above my pay grade, so if anyone replies to this with university-level math, it will go over my head. But, it still raises my eyebrow whenever I see one of Erin's reviews or read where Amir suggests the correction.

Thoughts? Thanks!
 
These are my personal opinion -- generally I would not EQ above 400Hz or so. However, if I wanted to adjust the tonality of the system/speaker, I can under the constraint that the PEQ gain adjustment level is small (say +/- 2dB or so), and Q is quite wide (say Q<=2 or so).

I have played with the BBC dip PEQ around 2.5kHz ... it does make some speaker "less harsh".
 
Rooms affect frequencies above 500hz. There is no reason not to equalize all frequency bands to adjust for broadband effects like room absorbency, personal preference, and deficiencies in speaker response, provided you have have good data on the latter.

Audio is ultimately subjective. There are no completely accurate transducers on the market, there are simply some which are relatively sensitive to room acoustics and some which are less sensitive.
 
My take on this this is that eq over 500hz in general should be used sparingly to 'correct' an issue that the speaker may have that is not to your liking. Like a bit of a peak at a certain frequency. This sound is baked into the speaker as part of its frequency response/linearity so it would be a fools errand to go wholesale and try to 'correct' all of the frequency response, a better approach would be to correct for room modes and nudge very sparingly in the upper frequencies.
It's like ordering a chicken Korma for take away then trying to turn it into a vindaloo at home by adding extra spices.
Look at data before you buy or preferably have a demo in your room. For me eq is like seasoning, a small bit can elevate and too much will ruin but the dish has to be in the ballpark in the first place.
 
I am a very strong proponent of PEQ use at all frequencies for hearing the music better according to the frequency response of the transducers and for the ears frequency response as well. For that reason I compiled for ASR the PEQ webpage and use PEQ with very generous settings as I enjoy a large amount of high frequency and not so much bass. I use headphones and this is part of why I PEQ with vigor as you can see from my screen shot of my PEQ settings. Note: I am a extreme PEQ user and this is not for everybody.
PEQ (6).png
 
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I’ve always applied EQ -or room correction -at any frequencies needed to achieve the sound I prefer at the listening position.
If that means shaping a curve from 30 Hz to 20,000 Hz, so be it. Full-range correction is essential for me to get the sound I enjoy. Any potential flaws or errors in this approach aren’t noticeable to my ears.

The ends justify the means. :)
 
These are my personal preferences/approaches for your possible interest and reference...
Please refer to a few of my relevant posts on my project thread.

- A serious jazz fanatic friend came to my home for audio sessions using my multichannel multi-driver multi-way multi-amplifier stereo system: #438

- Excellent Recording Quality Music Albums/Tracks for Subjective (and Possibly Objective) Test/Check/Tuning of Multichannel Multi-Driver Multi-Way Multi-Amplifier Time-Aligned Active Stereo Audio System and Room Acoustics; at least a Portion and/or One Track being Analyzed by Color Spectrum of Adobe Audition in Common Parameters: [Part-11] Violin Music: #643

- The latest system setup of my DSP-based multichannel multi-SP-driver multi-amplifier fully active audio rig, including updated startup/ignition sequences and shutdown sequences: as of June 26, 2024: #931
 
it seems like more people believe we shouldn't EQ above 500 Hz.

They are wrong. I have used Dirac Live on four pairs of wildly different speakers (+ one sub) in my room – sometimes with additional correction with CamillaDSP. All speakers obviously benefitted from correction up to ~500 Hz compared to no correction and all speakers have benefitted to a larger or lesser degree from correction up to ~20 kHz. And even though I generally use a 'tightly focused' correction in Dirac the tonal improvements are apparent even far outside the sweet spot ...
 
Hello heboil,

about your question:
what Erin and Amir suggest about room-EQ, I don't know.
From my point of view:
Correcting the speaker makes often sensen, but also with some limitation.
Correcting afterwards the room above 500Hz could also make sense. I would prefere wideband EQs (Q<1,5) and always A-B the configurations (don't get fooled by the loudness effect).
 
Not sure about Erin but Amir eqs to the anechoic response of the speaker. Although he also sometimes filters out a room mode he knows he has through testing. The problem with allowing a room correction system in doing so above the Schroeder frequency is that it can not differentiate between room modes and reflections as well.
 
I am in the full range EQ camp but understand people that limit the correction window as well. Our rooms and setups are so very different that it would be difficult to find a common denominator.

There are many room correction systems out there, some potentially better than the others.
 
Hi everyone and happy holidays!

I know people ask the question and there is some debate back and forth about EQ'ing/room correction over 500 Hz. From everything I have read (which likely isn't even scratching the surface), it seems like more people believe we shouldn't EQ above 500 Hz. Okay... fair enough. But, here is where the conundrum or head-scratcher comes into play. We all come to ASR for Amir's reviews and everyone here pretty much loves Erin's reviews. I often see them reference applying correction to a speaker above 500 Hz to rectify a given problem.

So, those corrections are above 500 Hz. That is the heart of my question. Do Amir and Erin believe in applying correction above 500 Hz? Or do they only believe in correcting the "anechoic measurement"? Either way, you are still correcting above 500 Hz in the room. What if your room interaction with the "problem area" self-corrected it? If the room enhances the problem, would the correction make it better or worse? Again, this is now above my pay grade, so if anyone replies to this with university-level math, it will go over my head. But, it still raises my eyebrow whenever I see one of Erin's reviews or read where Amir suggests the correction.

Thoughts? Thanks!
Hi there

I was going to answer your original question in the room correction thread, but I gather you opened this thread in order to deal with the question in its own thread. So I will answer here.

In short: people are saying "don't use EQ above 500 Hz" with specific reference to the case where a microphone is used to measure the summed-sound frequency response of loudspeakers playing in a room, where "summed-sound" means the sum of the direct sound coming from the speakers, plus all the reflected sounds from all room surfaces and room objects, including multiple reflections over time. This, in fact, is exactly the measurement that automated room correction algorithms take. Unfortunately, our ears don't work that way. Well, they kind of do work that way below 500 Hz (some say 300 Hz, but let's use 500 for now), but they definitely don't work that way above 500 Hz.

That is why the advice is centred on 500 Hz. Below 500 Hz, the summed-sound frequency response is a reasonable indicator of what we will think the system 'sounds like'. So it makes sense to allow room correction algorithms to apply EQ in that range. But above 500 Hz, what we think the system 'sounds like' is much more aligned with the frequency response of the direct sound, not the summed sound. (Direct sound being just the sound arriving at the ears straight from the speakers, and excludes any reflected sound.) Above 500 Hz we do also respond to the attributes of the reflected sounds, but to a lesser degree than to the direct sound. But the measurement that automated room correction algorithms take is not direct-sound, it is summed-sound. So it is considered unwise to decide on EQ adjustments above 500 Hz based on summed-sound measurements. We are looking at the wrong measurement for that purpose.

That is not to say we should never EQ our speakers above 500 Hz, which is where I think you are getting confused, since you see Amir and Erin recommending such adjustments. If the frequency response of the direct sound from our speakers is not very smooth and flat, then it is good advice to consider applying EQ above 500 Hz... but it needs to be based on looking at a measurement of the direct-sound frequency response. This is exactly what Amir and Erin are doing. They have the right tool to measure the direct sound.

For a more detailed treatise on this point, take a look at this paper by Dr Floyd E Toole: https://aes2.org/publications/elibrary-page/?id=17839

cheers
 
They are wrong. I have used Dirac Live on four pairs of wildly different speakers (+ one sub) in my room – sometimes with additional correction with CamillaDSP. All speakers obviously benefitted from correction up to ~500 Hz compared to no correction and all speakers have benefitted to a larger or lesser degree from correction up to ~20 kHz. And even though I generally use a 'tightly focused' correction in Dirac the tonal improvements are apparent even far outside the sweet spot ...
Same experience. I was very happy with the effect of using Dirac full-range with my dynamic speakers. I have not yet tried it with my (dipolar) ESLs, but would be curious about anyone else's experience with Dirac + dipole.
 
As said above 500 Hz someone mainly "corrects" the loudspeaker response and such is done often better on anechoic data and not on a LP measurement with a predefined target which just happened with another loudspeaker, room and listening distance, such curves are only a result of such a combination. Some good comments from Floyd Toole on this topic can be found here:
 
You didn't state what you are using for correction. I use the simple Audyssey app for a Denon AVR. Although in theory there should be no need to correct above 500Hz, with the app you can very quickly get full frequency correction and then make a copy and turn all processing off over whatever frequency you choose. I've done it multiple times and found that I prefer full frequency correction. My room is pretty simple, just correcting for a couple of resonances. If you have a more difficult room, it should help even more. My point is that if possible you should try it yourself in your setup. It's nice to know what Amir thinks about the topic, but he doesn't listen in your home on your system.
 
Same experience. I was very happy with the effect of using Dirac full-range with my dynamic speakers. I have not yet tried it with my (dipolar) ESLs, but would be curious about anyone else's experience with Dirac + dipole.
My experience with Mag. 3.7i speakers was that Dirac performed best when confined to 300Hz (or so) downwards, with adjustments to the upper tonal balance accomplished with Toe-in, Tilt, and Pads (resistors). In my situation, Dirac above 500Hz tended to reduce the specificity of individual instruments, i.e., scramble or homogenize the image. With their monopole replacements, I'm not afraid of "voicing" the upper octaves with EQ, but still confine Q>1.4, Gain>2db adjustments (real room correction) to 300Hz and below.
 
With 100 sweeps on same location and speakers you Will have 100 different outcomes above 500 hz.
You cant correct for something you dont know what it must be.
 
Hi there

I was going to answer your original question in the room correction thread, but I gather you opened this thread in order to deal with the question in its own thread. So I will answer here.

In short: people are saying "don't use EQ above 500 Hz" with specific reference to the case where a microphone is used to measure the summed-sound frequency response of loudspeakers playing in a room, where "summed-sound" means the sum of the direct sound coming from the speakers, plus all the reflected sounds from all room surfaces and room objects, including multiple reflections over time. This, in fact, is exactly the measurement that automated room correction algorithms take. Unfortunately, our ears don't work that way. Well, they kind of do work that way below 500 Hz (some say 300 Hz, but let's use 500 for now), but they definitely don't work that way above 500 Hz.

That is why the advice is centred on 500 Hz. Below 500 Hz, the summed-sound frequency response is a reasonable indicator of what we will think the system 'sounds like'. So it makes sense to allow room correction algorithms to apply EQ in that range. But above 500 Hz, what we think the system 'sounds like' is much more aligned with the frequency response of the direct sound, not the summed sound. (Direct sound being just the sound arriving at the ears straight from the speakers, and excludes any reflected sound.) Above 500 Hz we do also respond to the attributes of the reflected sounds, but to a lesser degree than to the direct sound. But the measurement that automated room correction algorithms take is not direct-sound, it is summed-sound. So it is considered unwise to decide on EQ adjustments above 500 Hz based on summed-sound measurements. We are looking at the wrong measurement for that purpose.

That is not to say we should never EQ our speakers above 500 Hz, which is where I think you are getting confused, since you see Amir and Erin recommending such adjustments. If the frequency response of the direct sound from our speakers is not very smooth and flat, then it is good advice to consider applying EQ above 500 Hz... but it needs to be based on looking at a measurement of the direct-sound frequency response. This is exactly what Amir and Erin are doing. They have the right tool to measure the direct sound.

For a more detailed treatise on this point, take a look at this paper by Dr Floyd E Toole: https://aes2.org/publications/elibrary-page/?id=17839

cheers
And isn't that exactly why you should do gated measurements over 500hz to only EQ the direct sound?
But tbh I haven't done any gated corrections myself (yet), I just do normal measurements, correct the bigger peaks all over and then apply some subjective curves on top of that and have always been happy with it :)
 
EQ above 500 (or 300hz depending on who you ask) is fine if:

You use wide filters only, to shape tonality but not correct anything per se

Or:

You correct based on anechoic response AND Your speaker has smooth directivity so you don't throw off the total response

Narrow filters for correcting in-room response are only valid in a listening area that corresponds to the wavelength of the frequency you're correcting, which shrinks to fractions of an inch at high frequency. At low frequency they are more like 10 feet, so very worth doing.
 
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