Speaker EQ, Full Range or Bass Only (with Poll)

[Sal1950]

I'd like to start a general discussion on the topic of Speaker EQ.
As I posted elsewhere, I find it very curious why full range EQ is totally accepted in the headphone world, while only bass range (below Schroeder) EQ gets wide acceptance for speakers?
Whether done with DRC applications or free-hand using different types of analog hardware/software, I oft been very confused on the subject.
I've read opinions from folks I respect on both sides of the issue and thought it'd be interesting to throw the question up here for general discussion.
TIA Sal

 

[Blew]

At a guess I'd say because speakers are usually in lounge settings while headphones are usually listened to at a desk on a computer, meaning most people have much less DSP processing power available for speakers (typically on an AVR), meaning the speaker DSP creates noise and distortion which is more perceptible at higher frequencies.

 

[kemmler3D]

why full range EQ is totally accepted in the headphone world, while only bass range (below Schroeder) EQ gets wide acceptance for speakers?

As far as I understand it, this would be because sound doesn't bounce as much on its way to the ear in a headphone as it does in a room, there is no "off-axis" to worry about with headphones, the ear is more or less fixed in space relative to the headphone, and the wavelengths are mostly large compared to the headphone / ear cup.

When those things aren't true, you end up with EQ that only works "to a spot" or you make the sound worse in one place as you improve in another. Basically EQ fails when it doesn't correspond linearly to what hits your ear. With speakers this is mostly doable below Schroeder, but above that there are many gremlins.

There is also the fact that getting an anechoic measurement of your speaker is not trivial, so even figuring out what you're really EQing isn't easy.

All that said, I think doing speaker EQ full range is ok if you're careful. Wide filters and avoiding putting filters on off axis funkiness (directivity errors) can help.

 

[voodooless]

Full range speaker EQ is perfectly fine if you know what you’re doing. You can be more liberal with your EQ in areas where the room influence is large. Beyond that, more care must be taken. Best to use different window settings (and possibly averaging) for the measurements to remove the room as much as possible, then EQ the speaker response, and finally apply the house curve you prefer to have for the whole thing.

 

[staticV3]

I find it very curious why full range EQ is totally accepted in the headphone world, while only bass range (below Schroeder) EQ gets wide acceptance for speakers?

The reason why EQ above Schröder is inadvisable for speakers is because human ears can to some extent discern direct sound from reflected sound, but microphones can't.

An in-room response measurement contains the sum of direct and reflected sound. Correcting that sum may screw up the direct sound, which can sound bad.

Hence, use in-room measurements to correct below Schröder and anechoic measurements above.

Headphones OTOH are 100% direct sound, so correcting full-range is AOK.

 

[Blumlein 88]

Toole et al looked into this. The conclusion was not to do "Room Correction" full range. Blind testing using a few different such systems didn't show an improvement except with two of them. One of those when it was revealed was the Tact system which I had years of experience with.

One conjecture is that maybe the Tact system was better because it used impulses for testing and not gated sweeps. The later versions used two impulses one for low frequencies and one for everything else. As voodooless said above using different window settings and applying house curves is necessary to get the best from it.

My further experience is with good speakers that have good spins the gains are less. However, with speakers you may like for other reasons and with poor spins such correction well applied is more helpful. Not surprising as a speaker far from a good room curve stands to gain more. Some things you can never fix fully, like speakers with first order crossovers that for that reason have significant peaks and dips off axis. You can massage the total result to be better balanced. It isn't really "corrected" however.

 

[Purité Audio]

What are the effects of correcting in the non minimal phase region of the FR, personally I only recommend EQ for the lower bass ( minimal phase) , this is in rooms which are usually ‘traditionally ‘ furnished and using properly designed loudspeakers.
Keith

 

[amirm]

Do both and decide which sounds better with varied content.

The idea of not correcting above transition frequency comes from having speakers that have neutral response there. If the speaker doesn't, then correction with EQ definitely works as evidenced by my many EQ settings for speakers with colorations. Now, what an automated system does, is another matter. One key thing is their target curve which you need to customize to your taste. And another is them doing strange things you don't want them to do.

 

[Blumlein 88]

The Subjective and Objective Evaluation of Room Correction Products

In a recent article, I discussed audio’s circle of confusion that exists within the audio industry due to the lack of performance standards...

seanolive.blogspot.com

More data on the tests is here in this slide presentation.

The Subjective and Objective Evaluation of Room Correction Products.pdf

drive.google.com

Shows how your memory can be wrong and right. This was way back in 2009. 5 systems tested, one scored no better than no EQ, one was much worse, three scored better than no EQ. It was an early Lyngdorf rather than a Tact, but both were at one time the same company and worked the same. If my memory isn't wrong (again) elsewhere in forums he has said the Lyngdorf was the best scoring in that test. On a scale of 0-8 for preference with no EQ scoring 3.9 the best system scored 6.9 which is quite an improvement.

 

[Sal1950]

When those things aren't true, you end up with EQ that only works "to a spot" or you make the sound worse in one place as you improve in another. Basically EQ fails when it doesn't correspond linearly to what hits your ear. With speakers this is mostly doable below Schroeder, but above that there are many gremlins.

Thanks @kemmler3D !
Your thought here often comes up in other threads also, I believe we have to focus on what the system is mainly used for. If you have a multi seated home theater then evenness of response across the listening area can be of large importance. But whether this is a 2ch or multichannel rig I believe the majority of us do our serious listening from an MLP (main listening position) and having a system optimized for that spot is of prime concern. Maybe I have this view because I'm single, but I have at various times been married or lived with a lady and the few times she listened with me seriously, she would sit in my lap as we reclined in a big lazy-boy.

What are the effects of correcting in the non minimal phase region of the FR, personally I only recommend EQ for the lower bass ( minimal phase) , this is in rooms which are usually ‘traditionally ‘ furnished and using properly designed loudspeakers.

Keith, I'm wonder do you know what approach the built-in DRC systems for speakers like the D&D 8C or Kii 3 use?

Do both and decide which sounds better with varied content.

The idea of not correcting above transition frequency comes from having speakers that have neutral response there. If the speaker doesn't, then correction with EQ definitely works as evidenced by my many EQ settings for speakers with colorations. Now, what an automated system does, is another matter. One key thing is their target curve which you need to customize to your taste. And another is them doing strange things you don't want them to do.

Thanks Amir, my personal feelings run close to yours and the speaker reviews you've done where you tried some different corrections are
much of what inspired this thread. I'm think I'm going to add a poll to this thread to find the approach our members most use. Right now I'm thinking
over the options I wish to include.
Cheers all.

 

[kemmler3D]

But whether this is a 2ch or multichannel rig I believe the majority of us do our serious listening from an MLP (main listening position) and having a system optimized for that spot is of prime concern

As Amir says, smoothed measurements and wide filters can make this OK, but consider that the wavelength at 10khz is only 3mm. So if you corrected a flaw at 10khz at your MLP, the correction will be invalid 3mm away from that spot. Even at 2khz it's 171mm. So if you are correcting with room influence included, you could easily just make things worse if you correct with narrow filters.

If you just stick a mic at your MLP and slap a tight (maybe even FIR) full-range correction on there, the results tend to be bad.

 

[Purité Audio]

Thanks @kemmler3D !
Your thought here often comes up in other threads also, I believe we have to focus on what the system is mainly used for. If you have a multi seated home theater then evenness of response across the listening area can be of large importance. But whether this is a 2ch or multichannel rig I believe the majority of us do our serious listening from an MLP (main listening position) and having a system optimized for that spot is of prime concern. Maybe I have this view because I'm single, but I have at various times been married or lived with a lady and the few times she listened with me seriously, she would sit in my lap as we reclined in a big lazy-boy.


Keith, I'm wonder do you know what approach the built-in DRC systems for speakers like the D&D 8C or Kii 3 use?


Thanks Amir, my personal feelings run close to yours and the speaker reviews you've done where you tried some different corrections are
much of what inspired this thread. I'm think I'm going to add a poll to this thread to find the approach our members most use. Right now I'm thinking
over the options I wish to include.
Cheers all.

Sal, the 8Cs have the usual peq, frequency, gain ‘Q’ etc, all the various types notch, shelf etc and also ‘voicing’ where you can apply broader adjustments, you set the ‘from and to’ in terms of frequency and positive and negative gain in .5 dB increments.
Usually I just implement the minimum number and just in the low bass.
Keith

 

[Sal1950]

Sal, the 8Cs have the usual peq, frequency, gain ‘Q’ etc, all the various types notch, shelf etc and also ‘voicing’ where you can apply broader adjustments, you set the ‘from and to’ in terms of frequency and positive and negative gain in .5 dB increments.
Usually I just implement the minimum number and just in the low bass.
Keith

Ah, so it offers a much wider range of tuning options than I would have imagined.
Great for the knowledgeable owner, maybe disastrous for the Primitive Peter. LOL
Thanks

 

[GD Fan]

Ah, so it offers a much wider range of tuning options than I would have imagined.
Great for the knowledgeable owner, maybe disastrous for the Primitive Peter. LOL
Thanks

'Primitive Panther' should be a new ASR rating.

 

[holbob]

Thanks @kemmler3D !
Your thought here often comes up in other threads also, I believe we have to focus on what the system is mainly used for. If you have a multi seated home theater then evenness of response across the listening area can be of large importance. But whether this is a 2ch or multichannel rig I believe the majority of us do our serious listening from an MLP (main listening position) and having a system optimized for that spot is of prime concern. Maybe I have this view because I'm single, but I have at various times been married or lived with a lady and the few times she listened with me seriously, she would sit in my lap as we reclined in a big lazy-boy.


Keith, I'm wonder do you know what approach the built-in DRC systems for speakers like the D&D 8C or Kii 3 use?


Thanks Amir, my personal feelings run close to yours and the speaker reviews you've done where you tried some different corrections are
much of what inspired this thread. I'm think I'm going to add a poll to this thread to find the approach our members most use. Right now I'm thinking
over the options I wish to include.
Cheers all.

If you're going to do a poll make sure members can select multiple options, e.g. anechoic full range, bass only under schroeder.

 

[Purité Audio]

Ah, so it offers a much wider range of tuning options than I would have imagined.
Great for the knowledgeable owner, maybe disastrous for the Primitive Peter. LOL
Thanks

Quite I am sure I have mentioned the Kii Three/BXT speakers I had shipped all the way to The isle of Skye ( about as far away as one can get over here) the customer said they give him an instant headache.
When they returned I discovered that he had effectively turned the bass off.
The Kii distributor doesn’t even tell his retailers that the Kiis have peq!
Keith

 

[Sal1950]

Quite I am sure I have mentioned the Kii Three/BXT speakers I had shipped all the way to The isle of Skye ( about as far away as one can get over here) the customer said they give him an instant headache.
When they returned I discovered that he had effectively turned the bass off.
The Kii distributor doesn’t even tell his retailers that the Kiis have peq!
Keith

Yes sadly "you just can't fix stupid" pops up everywhere. LOL
The ability to make massive improvements also comes with the ability to make a massive disaster.
Some folks are just much better off with a plug-n-play Sonos.
I'm sure you offered this guy as much assistance as possible over the huge distances involved.
Being fair, since the demise of the brick and mortar dealers most people are just completely left to their devices. At least in the old days
if you had a good local dealer and showed your ignorance you might get offered the option of some level of support. Good thing we at least have
the internet today and might be able to gain some knowledge if your willing to put in the effort. Many (most?) just aren't.

 

[Sal1950]

Alright my friends, I've added the Poll.
I added the options I thought needed and allowed more than one choice for our members that have more than one system type.
cent' anni,
Sal1950

 

[Looneybomber]

2ch, full range, but I use EQ like I use salt and pepper. Everything in the preparation of the final product matters the most. After everything is done, EQ/salt to taste. I add 1db at 40hz, +0.5db at 125 and 250hz and reduce the 2-4khz range by 1-1.5db. Adds a hint of warmth and takes out the harsh frequencies that years of playing the flute have blessed (cursed) me with.

 

[theREALdotnet]

I use Dirac DLBC and always make pairs of filters for full-range correction and for Schroeder curtain. Which one I use depends a bit on the music material, but I most often prefer the curtain filter. Dirac makes it easy to switch between them on the fly, so I don't have to settle.