How to think about room correction settings like frequency range and gain?

[dominikz]

I really don't know what causes it but without the sub tuning with non-boost is impossible again. Below is a measurement with a slightly lower frequency on the sub.

IMHO this is very good already - I'd keep the sub as is and wouldn't touch it anymore for now.

The dip around 100Hz is IMO most likely caused by SBIR from the glass sliding door.
My suggestion would be to push the speakers back, closer to the glass. That should push the dip a bit higher in frequency, and might make it less deep.
EDIT: By the way, how far exactly is each speaker from its adjoining side wall at the moment?

Then re-run RoomFit, but adjust RoomFit correction frequency range to 20Hz-200Hz.

 

[Aziraphale]

The dip near 50Hz looks better. Have you tried playing with the phase control on the sub?

Not yet, it's on 0. I don't really know what that does, to be honest.

@dominikz Then I'll keep on the last sub frequency for the time being. At the moment the speakers are both 1.30m from the side walls and 23cm from the closest glass. How close to the glass would you put them?

Only thing is that the window frame is right behind the middle of the right speaker and completely to the left of the left speaker, which makes them slightly less symmetrical from that point of view.

 

[dominikz]

Hi dominikz,

Your response is so professional. Our team will check the variable smoothing option in REW and discuss how to implement it.

Has there perhaps been any development regarding variable smoothing implementation in RoomFit? Thanks!

 

[WiiM Team]

Has there perhaps been any development regarding variable smoothing implementation in RoomFit? Thanks!

Hi @dominikz ,

We have nearly completed the implementation of Variable Smoothing in RoomFit and plan to release it in the future app update. Please review the following newly supported smoothing options:

• Variable
• Psychoacoustic
• ERB Smoothing

 

[dominikz]

Hi @dominikz ,

We have nearly completed the implementation of Variable Smoothing in RoomFit and plan to release it in the future app update. Please review the following newly supported smoothing options:

• Variable
• Psychoacoustic
• ERB Smoothing

That is great news!

Variable smoothing is ideal for room EQ, especially for people who want to EQ accross a wider frequency range. It is detailed in the bass (allowing precise resonance correction), and highly smoothed at high frequencies (minimizing the chance of overcorrection).

Psychoacoustic and ERB smoothing hide too much detail to be useful for bass EQ IMO, but I guess it doesn't hurt to have options.

 

[catchmeifyoucan]

you guys are awesome

i wonder after trying roomfit a lot if its not better to leave the subwoofer out of the calibration. has anyone had results when it comes to this. what sounds better ?

 

[dominikz]

i wonder after trying roomfit a lot if its not better to leave the subwoofer out of the calibration. has anyone had results when it comes to this. what sounds better ?

Unless you already use another way to EQ the subwoofer response (like e.g. via subwoofer on-board DSP or external miniDSP device), it is definitely better to include the subwoofer in the RoomFit calibration.

This is because human hearing cannot really differentiate between reflected and direct sounds at low frequencies, so we more-or-less perceive them like we measure them in-room. And standing waves will usually create the worst peaks in the part of the spectrum where subwoofers operate.

In short - room correction (like RoomFit) is mainly intended to smooth-out the response <300Hz, which includes the subwoofer range (usually <80Hz). But proper loudspeaker and subwoofer placement and integration is a crucial precondition for RoomFit to work as well as it can.

Perhaps you will find this post interesting, where I tried to summarize what room correction can and can't do well.

Hope this helps!

 

[catchmeifyoucan]

Unless you already use another way to EQ the subwoofer response (like e.g. via subwoofer on-board DSP or external miniDSP device), it is definitely better to include the subwoofer in the RoomFit calibration.

This is because human hearing cannot really differentiate between reflected and direct sounds at low frequencies, so we more-or-less perceive them like we measure them in-room. And standing waves will usually create the worst peaks in the part of the spectrum where subwoofers operate.

In short - room correction (like RoomFit) is mainly intended to smooth-out the response <300Hz, which includes the subwoofer range (usually <80Hz). But proper loudspeaker and subwoofer placement and integration is a crucial precondition for RoomFit to work as well as it can.

Perhaps you will find this post interesting, where I tried to summarize what room correction can and can't do well.

Hope this helps!

thank you. my (stupid) thought was that a subwoofer depends on room reflections to perform its best. Thats why the manual often says; put it in a corner to get the best sound. When using room correction, wouldnt you make that go away ?

 

[EddNog]

thank you. my (stupid) thought was that a subwoofer depends on room reflections to perform its best. Thats why the manual often says; put it in a corner to get the best sound. When using room correction, wouldnt you make that go away ?

The best way to utilize a subwoofer is to take advantage of boundary reinforcement (walls and floors) to give the subwoofer more headroom, then utilize room correction or equalization to cap off the excess energy at the main listening position.

-Ed

 

[harkpabst]

thank you. my (stupid) thought was that a subwoofer depends on room reflections to perform its best. Thats why the manual often says; put it in a corner to get the best sound. When using room correction, wouldnt you make that go away ?

What @EddNog said.

And to put it in slightly different words: RoomFit will not and cannot remove the interaction between the subwoofer and the room. But it can and will equalise the resulting frequency response to be as smooth and flat as physically possible with the given positions of the sub and the listening place.

 

[dominikz]

thank you. my (stupid) thought was that a subwoofer depends on room reflections to perform its best. Thats why the manual often says; put it in a corner to get the best sound. When using room correction, wouldnt you make that go away ?

No problem!

Your question is insightful and shows you're trying to apply logic and to understand the recommendations - there's nothing stupid about that! You're just missing some context, which is completely normal because these are not exactly trivial topics.

The reason to put the subwoofer in the room corner comes from two main factors:

1. By putting the subwoofer in a corner we get significantly more output/headroom because the subwoofer radiates the same amount of sound into only a fraction of the space.
   • Think of it this way - subwoofer radiates sound in a sphere (i.e. omnidirectionally), so if we could suspend it in mid-air at the middle of a huge room the sound coming from the subwoofer would expand spherically in all directions: to all sides, below and above it. We often call this scenario "free space".
   • However if we place the subwoofer in a room corner instead, the sound going to the adjoining walls and floor is reflected immediately, so effectively the same amount of sound that in the "free space" scenario radiates into a sphere, in case of corner-placement radiates into only 1/8th of a sphere - meaning the in-room sound pressure level is higher as a result. This is why we call this "1/8 space" scenario.
   • Here's one illustration of the effect (source):
     
     
   • The downside is that this can make the sound boomy - but only if we don't have EQ (like RoomFit) to counteract it! This is why subwoofer corner-placement was usually avoided in the past, when acoustic measurements and PEQ were not as accessible.
2. By putting the subwoofer in a corner we avoid destructive acoustic cancellations (so-called SBIR notches/nulls/dips) that happen whenever you put any sound source any specific distance from a wall. The principle is illustrated in this very nice article by Genelec, but boils down to this illustration:
   
   
   
   In short, if the distance of a sub from adjoining walls and floor is <1m, then the nulls/notches/dips caused by this interference will be above 80Hz (the usual upper frequency the subwoofer reproduces). So a corner location is a nice, simple way to ensure this criteria is met.

Now that we understand what happens, we should come away with the message that putting a subwoofer in a corner will mean a) much more output, and b) that it helps us avoid sharp dips in the bass response (i.e. "bass suckout").

But what we haven't mentioned so far is that corner placement will also result in the strongest main room resonances/modes/peaks - these will come up as sharp peaks in the bass response, often 10-20dB above average bass level.
This is where room correction EQ (like RoomFit) comes into play - it will knock down these sharp room resonances, to give a pleasantly smooth bass response as a result. Without EQ the bass with a corner placed subwoofer would likely be very resonant and boomy.

So subwoofer corner placement actually needs some kind of EQ / room correction to work optimally - but if you combine them you get several benefits vs other placement options.

Hope this short description helps!

 

[catchmeifyoucan]

thanks guys, that clears thing up for me.