Perceptual Effects of Room Reflections

[Audio Science Pal]

It depends upon room size. Look up Schroeder Frequency; it is mentioned along with many other things here: https://www.linkwitzlab.com/rooms.htm

HTH - Don

Thanks for the link to that information.

 

[Count Dacula]

I'm working my way through the thread, but I thought I'd describe my quick and dirty room correction method.

I sweep the room with a tone generator, listening for resonating junk in the room. Window frames, heaters, drywall and trim...all get a quick tightening if I can get them to resonate. I'll even add some extra drywall screws if I'm going to paint.

This is my idea of room treatment via correcting the problems themselves, not compensating with a little box.

 

[Bjorn]

I'm working my way through the thread, but I thought I'd describe my quick and dirty room correction method.

I sweep the room with a tone generator, listening for resonating junk in the room. Window frames, heaters, drywall and trim...all get a quick tightening if I can get them to resonate. I'll even add some extra drywall screws if I'm going to paint.

This is my idea of room treatment via correcting the problems themselves, not compensating with a little box.

Removing resonances is good, but has nothing to do with room reflections and which is the topic here. Attenuating reflections is absolutely necessary for a great result.

 

[Sal1950]

Window frames, heaters, drywall and trim...all get a quick tightening if I can get them to resonate. I'll even add some extra drywall screws if I'm going to paint.

This is my idea of room treatment via correcting the problems themselves, not compensating with a little box.

Removing resonances is good, but has nothing to do with room reflections and which is the topic here. Attenuating reflections is absolutely necessary for a great result.

Amen Bjorn!
Count, there's no DRC system in the world that can remove the mentioned resonances, that can only be done the manual way which you described.
OTOH, the peaks and valleys in response caused by room nodes, specially in the bass areas, and be addressed in 2 ways. First and primarily thru
various types of room treatments such as reflection dampening panels and bass traps. Then the use of some type of DRC to flatten response electrically.
A combination of all the treatments is the best approach to getting the most from your system.

 

[teashea]

I'm working my way through the thread, but I thought I'd describe my quick and dirty room correction method.

I sweep the room with a tone generator, listening for resonating junk in the room. Window frames, heaters, drywall and trim...all get a quick tightening if I can get them to resonate. I'll even add some extra drywall screws if I'm going to paint.

This is my idea of room treatment via correcting the problems themselves, not compensating with a little box.

That does nothing to correct the real room issues.

 

[Count Dacula]

That does nothing to correct the real room issues.

Say it does "nothing", then you provide zero example of "real room issues"... ok dude. Great advice.

 

[Count Dacula]

Removing resonances is good, but has nothing to do with room reflections and which is the topic here. Attenuating reflections is absolutely necessary for a great result.

Who said I do nothing about reflections? Did my post say that?

This place is getting to be like a broken record.

 

[Count Dacula]

Yeah, I go thru the trouble to sweep the room, then I place my speakers facing the side walls in a bare room...that makes sense.

Maybe the polite, or at least economical, way to say it is, hey don't forget you gotta treat reflections too.....rather than trying to tell me I'm doing something wrong.

The contradictive personalities here just rampant. Any excuse to contradict someone is pounced upon here.

What ever happened to saying "good idea"? Say it, then add your step in the process. Chances are, it's not a mysterious surprise that other people already know what they are doing.

AGAIN, a little box isn't gonna fix resonances. It will compensate by turning down that frequency of the music, so then you hear the resonances all the better. Enjoy.

 

[Killingbeans]

What ever happened to saying "good idea"? Say it, then add your step in the process.

I think what people are objecting to is your use of the term "room treatment".

It's mostly seen as the disciplin of attenuating and/or diffusing refections + remedying the effects of standing waves below the schroeder frequency of said room.

There's no doubt that stopping objects in the room from resonating is a good thing, but it's not something that would normally be categorized as room treatment.

 

[krabapple]

I'm working my way through the thread, but I thought I'd describe my quick and dirty room correction method.

I sweep the room with a tone generator, listening for resonating junk in the room. Window frames, heaters, drywall and trim...all get a quick tightening if I can get them to resonate. I'll even add some extra drywall screws if I'm going to paint.

This is my idea of room treatment via correcting the problems themselves, not compensating with a little box.

That is rather basic. Necessary but not sufficient. It's a very limited idea of 'room correction'.

No 'little box' would or could ever claim to correct for those things.

But certainly there is useful room correction (digital and physical) possible beyond simply damping down object resonances.

 

[krabapple]

Say it does "nothing", then you provide zero example of "real room issues"... ok dude. Great advice.

How can you complain about that in good faith, if you've actually been reading this thread. It's all about 'real room issues', which go far beyond just things shaking in your room.

"This is my idea of room treatment via correcting the problems themselves, not compensating with a little box.", you wrote.

If all you really meant was, "this is how I correct one problem", then you should have written that. Not bitch at people who take your post at its apparent word.

 

[Sal1950]

I sweep the room with a tone generator, listening for resonating junk in the room. Window frames, heaters, drywall and trim...all get a quick tightening if I can get them to resonate. I'll even add some extra drywall screws if I'm going to paint.

Count, that IS a great idea for finding troublesome resonances in the room and probably the very first thing that should be done before any DRC or alike.

This is my idea of room treatment via correcting the problems themselves, not compensating with a little box.

I believe it was this sentence that was mis-understood as a replacement for DSP or absorbent panels.
But your right, we do sometimes look to correct when no correction is really needed.
That's a general problem with the internet vs face to face conversations, thoughts can many times be too abbreviated and lack clarity.
Cheers.

 

[krabapple]

Count, that IS a great idea for finding troublesome resonances in the room and probably the very first thing that should be done before any DRC or alike.


I believe it was this sentence that was mis-understood as a replacement for DSP or absorbent panels.
But your right, we do sometimes look to correct when no correction is really needed.

How many listening rooms in peoples' homes need no 'correction'* other than object resonance damping?

*Which doesn't necessarily mean 'little box' correction, though fixing modal issues at the MLP without them, is hardly a casual exercise.

Or are we saying that one person's measureable (and audible) room 'problem' is another's 'eh, doesn't bother me'?

 

[RichB]

Or are we saying that one person's measureable (and audible) room 'problem' is another's 'eh, doesn't bother me'?

Yes, we are.

- Rich

 

[kemmler3D]

I'm working my way through the thread, but I thought I'd describe my quick and dirty room correction method.

I sweep the room with a tone generator, listening for resonating junk in the room. Window frames, heaters, drywall and trim...all get a quick tightening if I can get them to resonate. I'll even add some extra drywall screws if I'm going to paint.

This is my idea of room treatment via correcting the problems themselves, not compensating with a little box.

Yes, as others have said, this is great practice for eliminating resonance in 'stuff' in the room, but the air itself also resonates, and unfortunately this cannot be fixed with glue or screws.

 

[Count Dacula]

Count, that IS a great idea for finding troublesome resonances in the room and probably the very first thing that should be done before any DRC or alike.


I believe it was this sentence that was mis-understood as a replacement for DSP or absorbent panels.
But your right, we do sometimes look to correct when no correction is really needed.
That's a general problem with the internet vs face to face conversations, thoughts can many times be too abbreviated and lack clarity.
Cheers.

I wouldn't mind seeing a scan of my room, just for reference or more like professional curiosity. "Reference" is a loaded term in this context. It doesnt' mean I want to put my signal through some kind of digital blender to compensate! Remember our old premise, less signal modification is better....what happened to that???? My hangout room is actually a bedroom with tons of clothes, mattress and carpet everywhere.. I'd be surprised if it had any fatal flaws....beyond the intense bass nodes that I find amusing.

As I say, you would NEVER attempt to "correct" a live musician in your room. The concept doesn't even make sense, ipso facto....the room is the room. You listen to the room. You're starting with a 20Hz-20kHz sound system, I just dont' see the problem...?

Since I got so verbose, I owe a better explanation of my statement. In a semi-sarcastic way, I think if someone has such sensitive hearing they need tiny db adjustments across the spectrum ( ) then they wont' actually even need a device to do the "corrections" for their golden boy hearing. Please don't internalize this, but I'm gonna say what I want to say.

The other thing for me went like this... my first experience with actual "correction" attempts via a familiar spectrum analyzer was some professional "dudes" my friends allowed in to "fix" the mediocre system in their nightclub that I had installed of scrap from a defunct club which we harvested vital organs from. The DJs kept blowing it up after I tried to keep it in check, and I couldn't be there to pick up the pieces every night. So they had these guys in to assess it and they did their scans with whatever software was popular in early 1990s. I would have liked a little more say-so, but I assume they set it flat. The next night everybody complained about the system. I said, hey we like highs and lows, but now you have a room full of screaming monkey meatbags drowning everything out. I was asked to re-tweek the system. What good was a scan for this condition? Not much, except maybe to have a peek at it....sure, to fix whatever it needs thru physical correction as much as possible.

Simple, create sound, and then destroy it. Funny, the club owner was an EE from Lehigh, who quit Bell Labs to open the club. I did other things for him as a friend, a custom Porsche stereo, etc ....because I was good. I think building car system from scratch of amps, x over and subs was the best possible education for home sound systems.


eta, last summer was the first time I remember having a system outside. One wooden wall behind small speakers, but to heck if it wasnt pretty amazing....a thing nobody ever talks about!

 

[kemmler3D]

You're starting with a 20Hz-20kHz sound system, I just dont' see the problem...?

Basically nearly all rooms have a lot of modes in the low frequencies, especially smaller rooms. If you have a full-range system your first 4-5 octaves or so tend to be total mayhem, >10dB peaks and dips are common.

These are pretty noticeable when listening to music (ever hear certain bass notes boom out or seem to go missing? Ever do a tone sweep and hear the volume fluctuate like crazy below 500hz or so?) and the easiest (usually cheapest) way to fix them is with DSP.

You can also use bass traps and whatnot, which help more, but DSP can get you pretty far.

Improperly deployed DSP can definitely make things worse, as it sounds like it happened in that club... but done right (which is much easier using REW these days) it tends to be night-and-day. These days I would say it's really unfair to call EQAPO or a WiiM unit a "digital blender". Things have improved quite a bit in practical terms since the 90s.

 

[Count Dacula]

I think what people are objecting to is your use of the term "room treatment".

It's mostly seen as the disciplin of attenuating and/or diffusing refections + remedying the effects of standing waves below the schroeder frequency of said room.

There's no doubt that stopping objects in the room from resonating is a good thing, but it's not something that would normally be categorized as room treatment.

Room Treatment, Room Correction....these terms interchangeable in my mind. I think the group might have to redefine or expand that definition. I mean, it doesn't actually "correct" the room, at all. Fixing nodes and fixing resonances.... some overlap there. I understand the conceptual differences, but in reality we're just "treating" the room.

 

[kemmler3D]

Room Treatment, Room Correction....these terms interchangeable in my mind. I think the group might have to redefine or expand that definition. I mean, it doesn't actually "correct" the room, at all. Fixing nodes and fixing resonances.... some overlap there. I understand the conceptual differences, but in reality we're just "treating" the room.

Room correction is probably more of a marketing term, but refers to DSP.

Room treatment or acoustic treatment generally refers to objects you put in the room to fix the sound.

 

[Sal1950]

How many listening rooms in peoples' homes need no 'correction'* other than object resonance damping?

*Which doesn't necessarily mean 'little box' correction, though fixing modal issues at the MLP without them, is hardly a casual exercise.

Or are we saying that one person's measureable (and audible) room 'problem' is another's 'eh, doesn't bother me'?

The contradictive personalities here just rampant. Any excuse to contradict someone is pounced upon here.

What ever happened to saying "good idea"? Say it, then add your step in the process. Chances are, it's not a mysterious surprise that other people already know what they are doing.

You mis-understood me krabby. LOL
I was just agreeing with the statement by Count that sometimes our members just look for any little detail in someones post to
correct or criticize. Happens everywhere I guess.
Cheers