Does the first reflection point actually matter??

@erik_squires 

So the other area which to me is more important is the floor between and behind the speakers.   It seems that treble harshness always lives there.

Definitely not first reflection points.

Can it be that the floor is closer to your tweeter than your sidewalls?
(I hope your ceiling is also further away from your tweeter than your floor) 😉

That may be the reason why you got that conclusion/s..

(The first reflection points are lik said on all the different types of room boundaries. The character and why it is called the "first" is it the "first" time the direct sound bouncing against a boundary. That means that each time a bounce is occurring some energy is lost into that boundary it reflects on. So the first reflection is the strongest one or let say it has the most energy left in it. If we look at if you play against the long wall and only look at the side wall reflections then the sidewall reflections is so far away and the sound need to travel so far that it will loose energy just because of that and as we also know is if the reflected sound is arriving to the listening position more than 5ms delayed than the ear brain can distinguish between what is reflected and what is the direct sound but if the side walls were closer/less than < 5ms than our brains can not separate what is direct or reflected sound.
As we see the replies in this thread is mixed because our experiences is with different distances to the side walls and nobody is specifying what distance to the side walls they have when they tell us their experience..)

I were thinking about..
If we ONLY look at the side walls reflections.
Then the first reflection points that the sound bouncing off.

My thoughts goes like this:
First reflection point is weaker (lower dB) than the direct. And what reflects of that surface is probably more higher frequencies than lower ones (Hz). 

That side point will act as a muted bass shy speaker that is delayed as it were placed further away..

Can this side walls reflection points contribute to a wider sound stage?
Or some other benefits that can be a argument to not treat side walls reflections?

(And of course the our experiences will vary greatly when we have all different distances from the speaker to the side wall in our unique rooms. So I would like to know what distance is used when we tell about our experience.)

A experience I have (sidewalls 80 cm away) it is like that helps or make it possible to hear sounds/instruments somewhere between the speaker and the first reflection point.. so extreme right or left will be beyond the speaker. Yes now when I think about it the sound stage is then wider.. 

But it is unintended wider and nothing the artist/producer were aiming for. And when first reflection point reflect a uncontrolled frequency response/range depending on what type of surface the effect will be more or less pronounced depending on the different frequency range different instruments has..

So I think I have answered my own question somewhat.. but how are your thoughts on this?

We can clearly say it is more than "some".
More exactly half of all reflections is good and the other half is harmful for stereo image.

Experiment: 
Put a wall of panels from your face in sweet spot that extends right in the middle to your front wall between the speakers.

The sound stage is incredibly and will never be better than this.. ..yes it looks stupid and is impractical but just as a experiment.

In short we have one room for left and another for right and the reflections from each speaker is there BUT they are totally separated.

That shows us how "harmful" to the sound stage perception, the first reflection point from the right speaker in the left wall that reach the left ear.. that were intended for the other ear.. and vice versa.

So half of all reflections (when we can see the experiment as we have two separate rooms left and right) is not good or is just destroying the sound quality. And if you have done the experiment then you will most likely agree.

3. No need to buy software to measure the room since the problems are obvious and better spent on product.

What? I am not considering my self as a measurement guy. But that is the just so wrong on so many planes.
It is like saying don't give someone else money but instead give it to me.
On the other hand not many buy the software when it is free.. on the third hand you need only buy a calibrated microphone that cost peanuts (65-100 USD). 
You need to learn to use the software or get someone that can.

Nobody trust me nobody can hear what you are able to find out by measuring. (You have never heard someone say "Oh that room has a 10 dB big dip at 53 Hz" for example. But measurement will show you exactly that and much more)
You can determine what effect after that you got after putting 7000 $ into your room

1. You should see on your measurements that your decay times is considerably lower over the whole frequency band.
2. Less amount of peaks and dips

How do you quantify that the sound after you spent 7000 HAS got better? Are you and Foly sitting in your sofa and subjectivity nodding to each other and saying "yes it sounds better.."

It is like emperor new clothes nobody dear to say something negative..

Plus he knows that if you don't do a measurement then you will not after the treatment say to him "Look there is still a 10 dB gain at 100 Hz (for example) after the treatment as it were before..

Plus he knows that if you get the gear and make measurements with the free software that you are halfway to be able to make a active correction.. you need "only" to take that measurement and export and then import to the DSP for it to correct your room..

To push you into that direction is only loose loose for him. When you can make demands on how much improvements you should and would expect..

But yes I am also of that opinion that we should fix the room with room treatment as far we can do THEN using active DSP.

But you NEED to measure to have and to get a baseline..
Measuring is knowing! 

(On a personal plan I think you will destroy that beautiful space. With all of those windows there is not much space to put all the stuff.. and making that project very hard from a esthetic point of view.)

Yeh Brad that is a very valid point!

Some horns are symmetrical some have more width than height. That gives narrower spread up and down. And will result in less issues with ceiling and floor first reflection points. That I have experienced.

Eric I would put it like this. As we KNOW that the FIRST bounce (reflection point IS the strongest/highest in dB. Then it more energy (dB) that we can transform to friction with absorbing panels. And 2nd, 3rd reflection, and so on is, each decreasing in energy for each reflection that is done.

So if we only have 2 or 4 panels and want to absorb as much reflections from the room boundaries. Where should we places those few panels to get the most absorption as possible with those few panels? Yes at the strongest one of course.

If we wanted to preserve the side reflections but we wanted to absorb the same amount of dB but only treated the 2nd, 3rd and so on reflection points then we need much more coverage than what just 2 or 4 panels could contribute with.

So we see that first reflection points is giving us most bang per square unit of panel/treatment.

(As for me I want in general listen on what is in the recording and not get the "color" and delay of room boundaries.
The "color" is defined by what material the room boundaries consist of. We know that dry walls and concrete walls reflect different amount of dB for each frequency (frequency response). So we can consider that in a concrete there inside that wall sits a mixing engineer that use litle more level on the bass faders on his console compared to the mixing engineer in the dry wall.
Sorry for that dumb analogy.) :D

Duke, that's a great post you made there. I can only agree. :)

Of course quantity trumps.

If you have 6 or 40 panels. 40 is 6.66 times more area than only 6 panels.
And when a reflection is more than reflecting one time. Let say it bounces 3 times before it is so week that it is -60 dB.

Then we have 6.66 times x 3 bounces gives us 20 time more treatment... 

So that is why we do not react or find any big difference on if you treated the first reflection points or not when I'm comparison to a room that have 20 times more treatment than the other!

I still say not all have of different reasons (time, founds or ascetics) not willing to get 40 pieces of treatment all over the room.

In most cases maybe you only buy 2/4/6 panels maybe bigger and thicker 1m x 0.5m each.

And we known for each reflection sound does it get weaker and weaker. So if/when you only got a few panels (less of a coverage area) then we start to treat the strongest reflection that is the first one. Of course absorbers will not take all reflection away. And of course the few panels will not contribute as much as if you had 6.66 times more panels and coverage area.

But it is for most of us a starting point and we can always add more panels along the way.

First, to the extent that absorption is more effective at short wavelengths than at long ones, it will change (darken) the spectral balance of those first reflections. That may still be a worthwhile net improvement if the room is overly reflective, but in general it is desirable for the reflections to have approximately the same spectral balance as the direct sound.

Yes, that is a problem higher frequencies is easier to absorb than lower ones. And will result in darken and we loose the "spectral balance".

It is good to always keep that in mind when we choose asorbent treatment. When we known that the lower frequency gets and the wave lengths get longer the thicker the panels need to be. For them to to have a high absorption coficient lower down in frequency.

Yes in practice the depth will be unreasonably thick.. So you can never have to thick panels so no worry there.

But if we always go as tick that we can or care for is desirable. 

To lessen the risk to end up with a dark/lifeless acoustic sounding room. 

We see that it is not only coverage area that matters. It is the thickness also. 

I would chose fewer and thicker absorbers than many more of them and thinner ones. To not get the issue that is in citation above.

Remember it is in bass their is the most energy and the most difficult frequency range to treat and therefore the most problematic. And will not get solved easily.

I have big few panels that are 19 cm thick (I wish they were thicker) on first reflection points (and two in the corners their bass builds up) I always think "bass first". When we put up absorbers we get a reduction of high frequencies "automatically". 

Another "trick" to get the absorbers you have to get better asorbtion coefficient at lower frequencies is to distance your panels from the wall. They will act as they are thicker than they are. All to just try to optimize bass absorption that we are in disadvantage at the get go.

I hope this helped someone. :)

I saw a interesting video about carpet and first reflection floor points.

Here is a myth to bust!

The carpet that we can see as a thin sound absorber do NOTHING to the first reflection point on the floor.

Instead what the carpet do is that it absorb only/mostly the high frequencies instead from 2nd and higher order of reflection.

Something to keep in mind. Look at the graph in the video:
https://youtu.be/GpDHo1jNhss

This example with thin carpet shows that we should always go for the thickest absorbers that we can get.

I found too much absorption on the side reflection points over-damped the sound. I opted for Vicoustic Wavewood diffuser/absorbers in that area, which sounded much more balanced than my thick DIY absorber panels.

That is good to hear! I love your room!
As you say the "Vicoustic Wavewood" is not the same as absorbing panels when they reflect more of the higher freqencies sound on most of the area.

I look at your pictures. And that mat is great for just that. To tweek how much "over-damped" sound we like to have or not.

As we know the floor mat does nothing for the first reflection point on the floor but it acts as a thin absorber that it what it exactly is.. So it absorb only the high frequencies (she the link on the subject that I posted earlier)

So if you experience "over-damped" then out with the mat. If it is to lively in with the mat. :)

Another observation is that low bass is radiating omnidirectional so those low frequencies are radiated behind the speakers. I see great corner bass absorbers. But there is also thin foam that will not help against that the bass is reflecting from those surfaces. Instead those foam will only take hi frequency reflections and also contribute towards "over-damped" feeling. Maybe remove or replace with thicker absorbers.

Is those cool white 3d diffusers the "styrofoam" or other material?
(I never had any experience of them and it is great to hear that they work in that material in that case)

There is so many variables. 
We have all different speakers with more or less amount of high frequency output.
Some sit with a "full range" tang band 8" and others has more/higher frequencies + added super tweeters. 
I guess the last example will probably more likely need more absorption coverage area of the walls.
(Then it is a good idea to take in and out the carpet if switching between those two different speakers in the room. A way of "Tuning" the room depending on what gear is used.)

OK, we can see it as the acoustics in the listening ROOM and the acoustics in the recording ROOM. 
The record "CHASING THE DRAGON - AUDIOPHILE RECORDINGS VOL 1" from Mike Valentine. Has two tracks:

2. Cello Interior: Bach's Cello Suite No. 1
Interior: In an English church, 3 M50's were set up to record cellist Justin Pearson performing Bach's Prelude. Between the mic, a Jecklin Disc was placed. This increased the separation of the spaced pair. The acoustics of the church are wonderful!
3. Cello Exterior: Bach's Cello Suite No. 1
The same microphones, performer, cello and the same piece of music... but this time recorded outside in the graveyard! How important are acoustics? What would it sound like to be able to remove the church from the last recording? Compare the tracks to hear for yourself the results of this interesting experiment! Which do you prefer?

It is very benefiting that our room do not has its own colorfull acoustics then you are not hearing what Mike Valentine intended us to hear in his recordings.
If we exaggerate and take and rig our stereo in the "big English church" as our listening room and listen to track "3. Cello Exterior".

Then we will hear almost the same as if we used well treated room/earphones and listening to track "2. Cello Interior"!

So if we are listening in a reverberant, colorful room. We will get used to that and at the end it will be our preferences. But everything we play will get that reverb and color. That were not intended to be there by the technician/artist. But you now prefer it but we can if we want always adjust our preferences. (See below) :)

As in those two tracks, examples above I actually in the beginning preferred track "2. Cello Interior" over the "3. Cello Exterior". 
Because that is the normal sound that we are USED to hear it in a reverberant space as a room is.

But after a while I noticed that I changed opinion and started to like "3. Cello Exterior" more and more. When I discovered that when the room were removed and all of its reverberation and color THEN I easily could hear how the cello itself sounded and how the whole resonant cello body sounded without any room smearing all over it. That were a great educational experience for me (not every day you hear a cello playing in free air outside (closest we get to a anacoic chamber))

I am suspecting the common issue between these two ideas is the speaker dispersion: the wide dispersion having a stronger effect on first reflections, the narrower having less impact on reflection points. It is quite possible we do not know what the mid and/or tweeter dispersion of our speakers really is. If we don't know, we could attribute a lot of audible results to things that may be unrelated. The specs we are given don't come close to revealing this super important info.

Yes I think that to.
One concrete example that come to mind is the Klipsh RP600m (and for that matter any horn speaker.
The tweeter is reassess into a horn and some reviewers says that it is not a horn but instes a wave guide.. (Poteto potato)
Most reviewers has as the most no/little treatment in their listening space. And it gets product of the year reward and so on..
And I have thought of why it could be that higly prized by them.
And here is two reasons why among others. Is that the tweeter is so far in that if you look from the reflection points on the sidewall for example. Then you can't see the tweeter at all..
In comparison to a soft dome tweeter that is on the front baffle. The dome shape is there for making a wider dispersion pattern. 
So in other word the RP600m reduce sidewalls reflections and ceiling/floor depending how far our distances are. With the horn directivity.
The other party trick is that the tweeter plays down to 1500 Hz were the x-over point is before the woofer takes over. And the woofer has of course a wider dispersion.

Those two party tricks is a welcomed addition to its presentation. And something that may help it to win get some love from the reviewers in their space.