Should we correct to Schroder, or full range?

[Daverz]

1) Here is the partial up to 500 hz
2) I noticed this "amplification of uncorrected frequencies"....I could adjust that...I could also input a reduction...?

It's a pointless exercise with a 10dB peak at 5 kHz.

 

[Music1969]

But it's just going to follow the target and sound even worse though, won't it?

But how would you know if a different target would sound worse, if you don't actually try and listen?

It will achieve the target but if target is not good, it will not sound good. So you need to experiment with different targets.

Yours is too horizontal.

 

[Jarrett]

It's a pointless exercise with a 10dB peak at 5 kHz.

(Although that's likely worst case, as I measured around 79 db spl. Rarely that loud day to day.)

Right, and if I went ahead, does the range of 500 hz - 3 khz warrant a 4 db reduction?

 

[Jarrett]

But how would you know if a different target would sound worse, if you don't actually try and listen?

It will achieve the target but if target is not good, it will not sound good. So you need to experiment with different targets.

Yours is too horizontal.

I tried the target in this guide too https://archimago.blogspot.com/2024/06/multichannel-digital-room-correction.html but all that ends up happening is the correction ends up following that slope down and sound suffers

 

[Daverz]

(Although that's likely worst case, as I measured around 79 db spl. Rarely that loud day to day.)

Right, and if I went ahead, does the range of 500 hz - 3 khz warrant a 4 db reduction?

Can you do PEQ filters? I'd try bringing down the peak at 5 kHz and the wide bump at 10 kHz just to hear what it sounds like.

 

[Jarrett]

Can you do PEQ filters? I'd try bringing down the peak at 5 kHz and the wide bump at 10 kHz just to hear what it sounds like.

Yes, is it this filter?

The only thing that mystified me was the "Q." If I want it to effect 1 khz on either side of approx 4.5 khz, I have no idea what Q to try

 

[Daverz]

Yes, is it this filter?

The only thing that mystified me was the "Q." If I want it to effect 1 khz on either side of approx 4.5 khz, I have no idea what Q to try

Trial and error in the REW EQ dialog. Higher Q is narrower and lower Q is wider. Start with Q=1.0.

But really, what is going on here? Did I miss some background info about the speaker and room? No bass and those big treble peaks?

 

[Bjorn]

I got my umik-1 last week and am using it with Audiolense.

My understanding of the software is getting better, yet no matter what I do with a full-freq correction (different targets, good sweep, settings), the result still sounds like it's underwater, muffled, instruments lost in the mix, no air (oh and I have a small room). I stumbled upon the idea of a partial correction (Schroeder 500 hz) being a serious thing.

So I did a few of them, and this sounds more like what my ear wants. Going in the direction of improvement (your ears don't lie!). I think full-freq correction is more successful in tandem with room treatment.

That's what happens with brute force correction of non minimum phase behavior. You create a lot of phase distortion.

Use better speakers, add the acoustic treatment you can do and only correct peaks below 200 Hz and some tonal shelving. Use a miniDSP Flex or something similar instead of Audiolense. With Audiolense you don't really have control of what's being done and correced.

 

[Jarrett]

Trial and error in the REW EQ dialog. Higher Q is narrower and lower Q is wider. Start with Q=1.0.

But really, what is going on here? Did I miss some background info about the speaker and room? No bass and those big treble peaks?

Yeah, I didn't mean to get into it all more to address that a partial correction is serving me better. Thanks for the PEQ suggetion!

It's a Kinima Hi G1 (low end starts at 50 hz) from early 2000s, on sand-filled floor stands and a Bryston B60 and Topping E30 II Small room 11x13 or so (two large windows I might add - I measured with the curtain open, which is most typical - I know they reflect lol). I know it's a problem, but buying the mic was something on my list to get into dsp, and I'll still have it when I get my own place!

@Bjorn Yeah, upgrading them is on my list, so hard to know if something will be an upgrade - should I set up a budget and find something that measures well like what Amir has been doing with speakers?

 

[Bjorn]

@Bjorn Yeah, upgrading them is on my list, so hard to know if something will be an upgrade - should I set up a budget and find something that measures well like what Amir has been doing with speakers?

Spinorama is quite misleading and we see high scores given to speakers that has a collapsing polar. A constant directivity only in the treble area, small drivers with high distortion, crossover smack in the sensitive area, and no focus on minimizing detrimental vertical reflection is not a good speaker design!

 

[thewas]

Spinorama is quite misleading and we see high scores given to speakers that has a collapsing polar. A constant directivity only in the treble area, small drivers with high distortion, crossover smack in the sensitive area, and no focus on minimizing detrimental vertical reflection is not a good speaker design!

Spinorama and Harman score are two different things and shouldn't be confused. Loudspeakers with smooth on- and off-axis responses get high scores and those correlate well to real AB blind listening tests, while your claims about all such loudspeakers being not good speaker design don't, so please don't present them as facts, even more as a commercial competitor.

 

[Mnyb]

I would like to gather opinions from ASR members as to whether we should apply room correction to the Schroder frequency, or whether we should do full range correction from 20Hz - 20kHz. There appear to be two schools of thought:

- Correction to Schroder: aims to only correct bass peaks and dips, leaving everything above Schroder uncorrected.
- Full range correction: bass peaks and dips are corrected, and an overall target curve at the listening position applied.

In my own system, I only correct to Schroder. I have tried a full range correction before, but it sounds awful. And this is with using very generous smoothing for upper frequencies. This made me ask myself whether there is something I am not measuring which, when correction is applied, makes the upper frequencies sound shrill (even with the Harman curve). The most obvious thing I am not measuring is the speaker's off-axis response and sound power, because it is not easy for me to do so. My speakers weigh 110kg and are physically massive, so it's not easy to take them outside and hoist them without hiring a forklift or something similar.

I have seen debates between proponents of both approaches. My theory for people having different approaches is that different systems need different types of correction. For one, most of us do not know what the directivity of our speakers are, and even if these specs are published, we can't exactly load them into our DSP software for correction. Also, different rooms may modify the spectral response in different ways.

So, I would like to know: which approach do you use, and why?

Hoping to hear responses from @mitchco and @UliBru

Correct for peaks (not necessarily full dampening) below Schroeder, and then gradually more careful through the transition range. Rule of thumb: No EQ above 500hz, rarely above 250-300hz.

Don't use DSP to force a different target curve than what the speaker would naturally reproduce in your room.

Correct to Schroder only. if you believe the reasearch.​

IE i wont be room correction anymore above the transition band as you brain gets involved and do and can separate out the speaker, beloow the transition your brain think the speaker and room are the same . As you cant EQ reflections separate from the direct sound your brain will hear that the direct sound is mangled as that is the dominant source for you above the transition band ( some chapter in Toole's excellent book I'm at work cant cite correctly )

However you can correct for the speaker itself above the transition band and make general wide tonal adjustment to taste or in my case being close to the speakers makes them a bit brighter -0,25db in the >500Hz solves that for most program material for my taste.

target curve is bad name it should be called "result curve" because it's not a target for RC . Because if you force a badly behaved speaker to fit a curve that well behaved speakers would give in room your only getting weird direct sound again , not a well behaved speaker .

You might like the result of a "target curve" , but then it's about taste not actually making better fidelity

 

[GXAlan]

target curve is bad name it should be called "result curve" because it's not a target for RC . Because if you force a badly behaved speaker to fit a curve that well behaved speakers would give in room your only getting weird direct sound again , not a well behaved speaker .​

But what if you have a well-behaved speaker anechoically which doesn’t provide a nice result curve in-room at the MLP due to things like very reflective surfaces near one speaker but not the other?

I think the extreme of taking a poor speaker and forcing a strict “result curve” is bad. We don’t need to correct the sound of a violin in a bright or dampened room because our brain can listen through the room. However, what about correcting the sound of a lightsaber? We don’t imagine that a lightsaber is in our room — we imagine that the lightsaber is in the environment that is being presented to us in the movie…

 

[Sokel]

Also "Schroder" is not something written in rock,one has to calculate it for its room.
The usual 400-500Hz is not right,at all.
Mine for example is in the hundreds,some other friend's may be even lower or much higher.

 

[Purité Audio]

REW is capable of showing you the minimal phase regions of the FR, ime I would only correct there, decent speakers to begin with and some form of room treatment even a bookcase for the higher frequencies.
Keith

 

[Mnyb]

But what if you have a well-behaved speaker anechoically which doesn’t provide a nice result curve in-room at the MLP due to things like very reflective surfaces near one speaker but not the other?

I think the extreme of taking a poor speaker and forcing a strict “result curve” is bad. We don’t need to correct the sound of a violin in a bright or dampened room because our brain can listen through the room. However, what about correcting the sound of a lightsaber? We don’t imagine that a lightsaber is in our room — we imagine that the lightsaber is in the environment that is being presented to us in the movie…

if it's a reflective surface very close it will probably be perceived as direct sound by the brain that is a valid corner case , but you need to know exactly what to do to not fudge it .

I sit to close to the back wall , I've got some room treatment there , suggest actual room treatment for the close reflections too if possible .

 

[Bjorn]

Spinorama and Harman score are two different things and shouldn't be confused. Loudspeakers with smooth on- and off-axis responses get high scores and those correlate well to real AB blind listening tests, while your claims about all such loudspeakers being not good speaker design don't, so please don't present them as facts, even more as a commercial competitor.

You need to keep in mind what speakers that are involved in those blind tests.
The result doesn't get better than the reference. One could also say that the Harman tests are very much a marketing tool.

It can easily be proven that there are for example speaker designs that will measure more even in the room.

 

[thewas]

You need to keep in mind what speakers that are involved in those blind tests.
The result doesn't get better than the reference. One could also say that the Harman tests are very much a marketing tool.

Some that weren't beaten yet, feel free to organise newer ones, it would be a great marketing tool.

It can easily be proven that there are for example speaker designs that will measure more even in the room.

An even LP measurement alone isn't sufficient to guarantee a better sound, a full spinorama and even more a controlled comparison listening test is needed for that.

 

[Newman]

But what if you have a well-behaved speaker anechoically which doesn’t provide a nice result curve in-room at the MLP due to things like very reflective surfaces near one speaker but not the other?

It's axiomatic that, if the speaker has a commendable Spinorama, then part of what makes it commendable is that it behaves well in real rooms, unless you are truly setting it up very poorly.

The setup you described is indeed poor. Your first priority would have to be to change the setup into a good one. Do something about the placement of the speakers, or treat the surfaces, or whatever you can possibly do. But if you are completely locked into the very poor setup you described, then some lowering of expectations is in order. By all means twiddle the knobs in a different way to what we have been describing, but there ain't no making a silk purse from that sow's ear. And as soon as you make the direct sound from one speaker have a different FR to the other, that's a big compromise.

cheers

 

[Snarfie]

IMHO Question could or must be "What theory an corresponding developed algo's are needed to Correct Full range with No artifacts" an which companies at least do an attempt to offer such DSP solutions. Point is those companies (besides REW which is a quality freeware/open platform solution) are not revealing their way of development/Algo's in detail. An that is understandable regarding their competitiveness/commercial goals. So some are offering Full range an some don't. One of the reason I'm on ASR because you find a variety of in depth information regrading DSP solutions.

@dominikz did a really good comparison/attempt between several DSP platforms very useful information IMO https://www.audiosciencereview.com/...-sonarworks-reference-4-studio-edition.18607/

What I am missing on ASR (or i missed it) an regular overview/update of possible promising solutions at least where to look for to get a Full correction done acceptable. A direct comparison/test between those solutions is needed which is difficult it requiers listening an will cause subjectivity. The room where it will be tested will not correspond what our rooms needed correction. So endless tweaking/measurements making use of REW for instance recuiers indepth knowledge to work with by far not ideal.

A recent (october 2024) paper about Exploring the Current Landscape of Open Research Software in Room Acoustics

https://pure.tue.nl/ws/portalfiles/portal/338789920/IN_2024_3656_revised.pdf

On ASR i came in contact with Mathaudio such that I was aloud to beta test their Mathaudio Room EQ solution.. An no I don't have any involvement with Mathaudio what so ever than I'm happy with their free an system wide solution an testing out of hobby curiousity. For specific my room acoustics FR this software did a great job but probably REW/APO, Dirac would/could do more or less the same (see comparison test Dominikz).

I put the question forward to Mathaudio regarding why the Schroder solution is used offent an recommended an how Mathaudio sees it their answer here under do know I'm not a acoustic specialist by any means:

“Mathaudio tested FIR filters and decided to not use them for Room EQ because they created a noticeable distortion at high frequencies caused by the pre-echo effect. On one hand, FIR filters are very simple and robust, on the other hand, they make sound dirty. It is possible that the idea of correcting "lowfrequencies only" is the consequence of people's bad experience with the FIR-based room correction systems”

Something similar is said by Peter Lyngdorf (fiddling, side effects like artifacts) who developed Roomperfect. Enclosed video he explained around minute 57:30 how Roomperfect is developed an around minute 58:30 he is talking about fiddling with hardware, target curves because people could not get the sound they wanted.

How exactly Mathaudio does room EQ i don't know they don't reveal (understandably) but at least i know they don't use FIR filters for what it's worth. It works for my specific room acoustics excelent using the Full correction. Can't say it will work the same better or worse for other rooms/situations.

To conclude I'm looking forward for DSP solutions with new alternative solutions that move boundaries to eventually close to perfect Full range correction. Maybe a question for AI how to resolve that eventually.

Enclosed measurement from my Vandersteen far fieldspeakers. Subjectively the white horizontal line (target curve) I use an also concluded by many others (who listen at my place) that this produced relative the best transparent result. Did make countless other target curves without any success. As you could see Schroder correction is pointless in my specific acoustic situation.