How to use Room EQ Wizard Pt. 2 - Acoustic Measurement Analysis

so you've taken measurements of your

room but now what what in the world

should your measurements look like which

graph should you use and how can you

take what your measurements are showing

you and turn that into an action plan

for improving the sound in your studio

i'm graham with music city acoustics and

in part two of our series on rew we're

gonna answer all of those questions and

help you make sense of your acoustic

measurements if you haven't already seen

part one click the link right here and

then come back and watch this video

it'll make a whole lot more sense so

let's jump right in

in order to actually be able to analyze

things well we need a complete

measurement set so we're going to either

measurement of your left speaker by

itself your right speaker by itself and

then the left and the right speaker

together and if you're using a sub

you're also going to want the sub by

itself as well as the left and sub

together the right and sub together and

then the left right and sub all together

as you'll see when we start going

through measurements we don't always

need that complete set of measurements

but if you're sending measurements off

to us or somebody else to analyze or you

want a better understanding of what's

going on in your room it is important to

take all seven of those measurements so

you can get a full picture and

understanding what's happening

and then a couple of quick notes and

tips on taking measurements you want

your measurement microphone to be at ear

height when you're seated in the

listening position and it should be

equidistant from your left and your

right speaker so to be perfectly

centered in your room so in part one you

may have noticed that i said you need

tape but it didn't explain why and it's

just that you can mark the location of

your speaker stands and your microphone

stand so you can put things back

once you determine where the best

location for those is in your room

it's incredibly important to use

consistent settings when you're

analyzing different measurements so let

me show you really quickly what can

happen to a measurement if you zoom in

and then zoom out

let's use this measurement here as an

example i've got my normal view limit

set and if i start to zoom out on this

measurement you're going to see just how

flat we can make what is obviously a

very wavy and inconsistent looking graph

look nearly ruler flat

so as you can see the same measurement

now was incredibly smoothed out and it's

not going to really reveal any

information to us about what's happening

in this room that's why it's incredibly

important to standardize your view

settings so you're always looking at

measurements under the same parameters i

have all of the view limits and

standards that i use for analyzing

measurements listed out below in the

description so check those out so you

can use them for your measurements so

quick interruption i've been editing

this video and it is dense and it's long

but it's got a ton of awesome info in it

i promise

so we're breaking this video up into two

parts part one is going to be

defining the measurements and showing

you how the graphs actually work and are

laid out and then part two we're going

to break down different example

measurements that we've prepared and

show you how to analyze your

measurements and really figure out

what's going on in your room down below

there are time stamps and chapters for

each section of the video so you can

jump around and go back and review

things later on so grab a pen and pencil

coffee and some snacks maybe and let's

jump right in

here i have our spl and phase graph

pulled up and what this is currently

showing us is the frequency response in

our room here and as you can probably

tell this thing is a complete mess right

now so we need to smooth this out so we

can actually start to see what's going

on in this room to do that i'm going to

head up to the menu bar in the top left

here and this will show us the different

smoothing options that we have smoothing

allows us to change what we're looking

at kind of reduce the resolution so we

can get a better picture of what's

actually happening the measurement

microphones that we use are much more

sensitive than our ears are and so while

the measurement mic can perceive all

these changes and variations that are

happening in the room we can't

so the psycho acoustic smoothing option

here this is the best depiction of how

we would actually hear the room and

perceive what it sounds like

it's not great if you're trying to hone

in on specific problems and really

figure out what you need to fix but it

is a very useful way of viewing

measurements if you're trying to figure

out you know how you should eq your

monitors or what the overall tonal

balance of your room is if i'm trying to

hone in on just a low frequency problem

i'll change my view settings here

and then go to 148th or 124th this still

gives us a lot of clarity and definition

so we can get a really good sense of

what's going on in the graph here but

also allows us to you know have a better

overall picture of what's happening so

we don't see quite so many of those

crazy squiggly lines going on if we're

trying to get a broader sense of what's

happening in the room i'll typically use

1 12 to 1 3 depending on what i'm

looking at

one third is the smoothing that is used

for pretty much every technical standard

and technical measurement so if you see

measurements of the speaker or a

microphone

those typically have one-third smoothing

applied to them and if you're looking at

technical standards for what a critical

listening room should sound like those

are also generally written with

one-third smoothing applied so if you're

reading through anything that says your

your frequency response should be plus

or minus 2 db to meet the ebu standards

that's plus or minus 2 db with one third

smoothing applied most of the best home

studios tend to fall a little bit closer

to plus or minus 5 db with one third

smoothing and as you'll see when we

start going through the example

measurements that's actually quite

achievable so i have 1 12 smoothing

applied to our graph here but even with

this it's quite hard to really tell

anything that's happening in the low end

so down in the bottom right here you

have this 20 to 20 000 hertz view

setting and then also a 20 to 300 hertz

if i click on that i can quickly change

on the screen what i'm looking at our

measurement is still falling off the

ends of our graph here i have my normal

view settings pulled up but if i zoom

out just a little bit now we can get a

better picture of what's actually

happening because we can see the top and

the bottom of this graph and now we can

start to see how much variation we have

if i hit control and right click

rew will tell me what the overall

variation in this room's response is and

so we can see a variation of 32 db or 33

db that's plus or minus 16 16 and a half

so this room as is has a huge variation

in its frequency response for an

untreated room or room with minimal

treatment this is completely normal

these things are ugly and they're going

to be really wavy so don't get

discouraged when you start looking at

your measurements making big changes can

be a challenge but every little bit

helps the spl or frequency response

graph is a great tool for comparing one

measurement to another or analyzing the

overall tonal balance of a room by

default this is the first graph that rew

shows us but it's actually probably the

least helpful or the least insightful in

terms of understanding what's happening

in your room so let's jump into some of

the other measurements that we have

available to us and we'll take a closer

look at what's actually going on in the

room in addition to our frequency

response we can also view our phase here

this will be super helpful if you're

trying to integrate a sub along with

your speakers we're going to take a

closer look at this a little bit later

on so i won't touch on it too much now

next up we have our impulse response or

energy time curve measurements here this

lets us see how sound is moving

throughout the room it'll show us over

time the sound arriving directly at the

microphone and then all the reflected

sound afterwards and how that's

impacting the overall energy in the room

so this is the impulse response window

and then up top we also have this

filtered impulse response i prefer using

the filtered impulse response because it

actually allows you to filter this by

octave band so if you want to hone in on

what's happening in a specific frequency

range you can do that by selecting a

different octave band here in the top

right for now we're going to take a look

at the unfiltered measurement so i'm

going to apply my normal view limits

here and we'll talk a little bit more

about what's going on in this room so on

the x-axis we have time plotted out

you'll see in milliseconds i like to

view this graph either from 0 to 50

milliseconds or 0 to 30 milliseconds in

an untreated room we're going to have

more reflections occurring later on so

50 milliseconds is more appropriate

right now our y-axis is showing us a

percentage and this is a percentage of

how much sound is occurring after the

initial sound source so if i zoom out

we'll start to see our initial peak here

is at 100 so this is the initial sound

source and then everything after this is

the decay in the room these are all big

reflections off of a boundary so either

the walls or the floor the ceiling or a

desk and then we can start to see and

analyze over time when those are

occurring and if we know when in time

those occur we can actually figure out

which boundary they're coming off of and

then determine where we need to put

treatment or what we might need to move

to smooth out some of those reflections

so you might have noticed this line

that's coming down here on our graph

that's the schroeder integral and it's

depicting the overall decay shape of the

room what we'd like to see here is to

have a very smooth decay

without any of these sharp drops or flat

lines moving across

obviously in this case with an untreated

room we've got a pretty uneven response

here but as we get into more and more

treated rooms you want to see that

really smooth out and have a nice even

decay it will also come way down so my

normal view parameters for this graph

actually only go up to 35 percent but

you'll see here

we completely cut that off if i view it

that way so in order to view this

untreated room you really got to zoom

out so we can get a better sense of the

overall decay of the room

rt60 or reverb time is something you're

probably actually familiar with it is

the amount of time it takes sound to

decay by 60 db now in studios we don't

typically use rt60 because it's very

hard to have that long of a decay time

and we don't have a truly diffuse sound

field so what you'll see in here is

actually t20 or t30 and a couple of

different options here if i'm analyzing

a studio i will pretty much always use

t20 as the timing reference here and

that's just how long it takes to sound

decay by 20 db instead of 60. in the

rt60 window our view settings or limits

will change quite a bit depending on

whether or not we're looking at a

treated room or an untreated room as

you'll see here i have this set to 1.5

seconds but if this room were treated

and for a normal control room or a mixed

room we want that reverb time to be much

closer to 200 milliseconds or between

150 or maybe 250 milliseconds so that's

all the way down here but obviously in

an untreated room we've got this huge

reverb time of over one second

so your limits will just kind of change

depending on what it is that you're

looking at overall what we want to see

in this graph is a very nice even decay

time we don't want any big changes from

one band to another as we get into

treated rooms this whole thing will drop

way down to here what typically happens

in well-treated rooms you have a nice

even response from the top of the graph

down to

100 hertz or so and then you'll start to

see the low frequency decay time to

slightly rise and that's completely

normal we don't want to have a massive

rise there so you don't want to go from

200 milliseconds to 700 or 500 but if it

goes up to 300 milliseconds or so

400 if the room doesn't have a lot of

bass trapping that's going to be pretty

normal so don't be alarmed if you start

to see a rise in the decay time of your

lower frequencies

that brings us to my two favorite

measurements the waterfall plot and the

spectagram and these both show the same

thing with just slightly different views

they're going to show us the overall

frequency response of the room and

you'll see that here on the waterfall

plot on the top and they also showed the

decay of the room across the frequency

spectrum so on the waterfall plot you'll

see on the right hand side here we have

time mapped out

and so as this graph is moving towards

us or towards the front of the screen we

can actually see the decay of the room

if i change our view settings here to

just the low frequencies we'll get a

better idea what that looks like so we

can see on the graph here we have

certain frequencies that are taking

longer to decay than other these peaks

that are coming towards us here at like

214

or over here at like 240. those are the

frequencies in this graph that are

taking the longest to decay so if we hop

on over to the spectrogram graph

we have the same information just shown

to us in a different way

so here on the left side of the graph we

have time

and then on the bottom right or moving

across to the right on the x-axis we

have frequency

and then the spl level of our

measurement is actually shown using the

colors here so the red color here is the

loudest highest spl level and then this

dark blue is going to be the quietest or

softest spl level in the measurement

and then we can very clearly see here

you know which frequencies are taking

longer to decay so if i change our view

settings here to just the 20 to 300

hertz frequency range we can get a

really detailed view of what's happening

we can start to see which frequencies

are lasting longer and taking longer to

decay and then which frequencies are

maybe missing some information or where

we have a null in our response this

allows us to get a really complete

picture of what's happening in the room

you can see both the frequency response

and the decay at each individual

frequency so we can put together a plan

on how to treat the room or we can see

if the treatments that we have in the

room are being effective

so like i said the waterfall and

spectrogram graphs show the same

information just in slightly different

ways for more detailed analysis of which

frequencies are decaying too long in the

room i like to use the spectrogram graph

because you can really hone in on the

detailed information here from one

frequency to another for overall

analysis and bigger picture views of

what's happening in a room the waterfall

plot is great

you might have noticed there's a few

measurements and graphs that we didn't

touch on things like group delay and

minimum phase some of the more advanced

sides of rew then there's also

measurements like clarity which we

didn't touch on and that's not something

that's used a whole lot in studios but

is used a lot in venues churches offices

if that's something that you want to see

let us know down in the comments below

and we can make a part 3 to this series

here i have two measurements pulled up

from my office i have a before and then

an after measurement the after

measurement was taken with our home

studio room kit installed and the before

measurement was taken with nothing in

this room we're going to go through all

of the different measurements and see

how things are changing with and without

that treatment there's a couple of main

points i want to go over one it's super

important to use the right treatment for

what you're trying to accomplish if you

want really really solid tight low end

you need big bass traps and you need

those bass straps to be installed with

air gaps behind them so they can work

well the second point is that the spl

graph like i mentioned earlier does not

tell the whole picture so as you'll see

when we're going through these different

graphs the spl measurement doesn't

change a whole lot we have a pretty

consistent frequency response between

these two measurements but every other

measurement is going to show a very

different picture so it's important to

use all those when you're analyzing your

measurements that you really understand

what's going on in your room so i have

the frequency response overlay pulled up

here and our before measurement is

marked out in red and the after

measurement is marked out in this teal

color and you can see we don't have a

whole lot of change happening here

between the before and after what we do

see is a change up here in the higher

frequencies and then in our mid

frequencies as well we see a lot more

variation in the treated room than we

actually do in the untreated room this

is a result of the clarity in the room

improving and that might seem a little

confusing as it clearly looks like the

graph isn't as smooth but what's

actually happening in that red

measurement or the before measurement is

all those reflections are smearing out

the frequency response of the room we

have a ton of reflected sound so there's

no real definition or clarity to the

sound in the space and that can actually

result in a flatter measurement but it

doesn't give you any detail or

definition and it doesn't really let you

hear the sound of your speakers because

you're hearing the reflected sound in

the room that's not to say that this is

what you want your frequency response

graph to look like there's definitely

more treatment that can be applied to

the space to make a big improvement to

the way this room sounds this room had

our home studio kit installed in it and

that's very much so meant to be a

starting point when you're treating your

room it doesn't have a ton of panels and

it doesn't have any big bass traps it

doesn't have anything capable of really

working below 100 hertz or so and that's

why we don't see any real change in the

low frequency response of this room as

you'll notice if we look at the graph

here our low frequency response below

100 hertz has almost no change to it but

in order to really affect change at that

frequency range you need big bass traps

you need them to be at least six inches

deep and then to really make them

effective in that range they have to

have at least six inches of air behind

them that really requires a total of a

12 inch deep bass trap and in this room

we mostly had high mid and broadband

panels that's why using the right

treatment for what you're trying to

accomplish is so important because

there's no way that we can change the

low end response of a room if we're not

using the right treatment so let's take

a look at some of our other graphs and

see if the treatment actually is making

a difference in the room now with our

atc measurement pulled up we can see a

huge difference in these two

measurements

which is a pretty striking comparison to

that spl measurement we were just

looking at now we can see our red

measurement or our before measurement

has a ton of reflected sound as you

would expect to see so the acoustic

treatment in this room actually is doing

quite a lot and we can see a big drop in

reflected energy which will translate

into a much greater level of clarity and

detail in the room and better stereo

imaging all of these red spikes here are

an increase in reflected energy and a

much longer decay time into the room so

with that in mind let's take a look at

our rt60 measurement and see what that's

telling us so the first thing i notice

is that i only have one measurement

visible on this graph it looks like both

are checked off so we need to adjust our

view limits here so we can actually see

the before measurement so let me change

this to 1.5 seconds and now we can

actually see it on our graph this is a

pretty wild change here we've got the

treated room down here living around 250

milliseconds or so with a with a sizable

rise in the low end as we would expect

to see because we haven't actually

treated the low end at all and then we

have our untreated room all the way up

here at around one second so the

treatment that we do have in the room is

very effective from 70 hertz all the way

up to 10 000 hertz it's just not doing a

whole lot below that like we talked

about while looking at the spl

measurement now i have the spectrogram

window pulled up so let's see what's

going on here so on first glance what i

notice is a pretty wide variation in the

colors so we've got some hot spots down

here in our low and low mids and then a

pretty big variation up here in our

highs and our mid frequencies and then

along with that we've got obviously a

very long decay time shown here with all

these blue spikes trending upwards of

600 milliseconds or so now let's jump to

the after measurement and we get a

pretty striking contrast here we have a

much more even dispersion of our red

color which is indicating a more even

frequency response and then on top of

that we obviously have the much improved

decay time in the room which we saw in

our rt60 measurement as well as the etc

graphs all of these things are showing

us that there was a massive change to

this room despite the fact that it's not

really shown on the frequency response

or the spl graph and that's why it's so

important that we use all the different

measurements available to us in rew so

that we can get a complete picture of

what's happening and really understand

how to improve your room

so let's talk about subs and how you can

tell if your speakers and your sub are

working well together

so i've got a measurement set prepared

here i'm going to pull up our overlay so

we can start to compare things

here's the frequency response of just

our speaker

and then let me add in just the sub so

we can see here our sub is starting to

fill in some of this low frequency

information that the speaker isn't

putting out and we very clearly have a

crossover occurring right around 56

hertz here and then pretty similar

responses up above that

what we want to see if we take a

measurement of the sub and the speaker

together is that those two sources are

working well together so they're adding

up to a more even response that has an

extended low frequency

if i add in our sub and speaker

measurement here now we can see we have

an extended low frequency response and

we haven't lost anything so our

crossover point is still having a

positive effect here we've gained

amplitude

the null that we had while we didn't

fill it we didn't create any new

problems so those two sources are

working really well together now i'm

going to add in another measurement this

again is our speaker and sub but this

time i flipped the phase switch on the

sub 180 degrees so we've got a pretty

striking contrast here now we have a

huge null occurring at 56 hertz right

where we saw that crossover point was

and the low frequency extension that we

had gained has been diminished quite a

bit higher up we are seeing some

differences as well but that sub was low

passed at 50 hertz so the main changes

that we're really seeing here and the

huge problem is this massive null that

we created and this is why having your

phase and your speaker time aligned and

correctly phase aligned is so important

because we need them to work together so

they're adding to one another instead of

subtracting or fighting each other

another way that we can analyze this and

ensure that our speaker and our sub are

working well together is with the phase

graph so this is shown with our

frequency on the x-axis and then on the

y axis on the left here we actually have

it shown in degrees so the phase

measurement is going to look pretty

different from what we're used to let me

hide most of these and then we'll look

at just the speaker and the sub

phase is shown in degrees so if you flip

the phase switch on something it's going

to flip 180 degrees out of phase so it's

completely reversed

so if we have something that's at 0

degrees and then we have something

that's a 180 degrees those two sound

sources will cancel out or fight each

other the same thing if you have it at

minus 180 or zero if we look at our

measurement here

we'll see that as we get higher in

frequency our graph is moving downwards

and that's completely normal what the

dotted lines indicate here is that as

our measurement is moving downward rew

has wrapped it so they just move it

straight up 360 degrees so we haven't

had any rotation or change to this

measurement yet but in order to keep it

on the graph so that it doesn't

continually trend downward

they've wrapped it so that we can still

see it and analyze it you can turn that

off up here so now you can see that this

continues downward and if i scroll over

it'll start to take a sharp dip and

obviously we can't keep all of this on

the screen

so we can wrap the phase so that it's

easier for us to analyze things and see

the complete picture in one window i'm

going to pull up our two sub

measurements our regular sub and then

our sub with the phase flipped so let's

take a look and see where these fall on

our graph so we've got minus 28 or so

here and if i move upwards we're going

to be at minus 149 or so so these are

basically 180 degrees out of phase with

one another so if these two sources

played at the same time they would be

completely canceling each other out any

time you're looking at a phase

measurement and we have two sources that

are completely out of phase with one

another we know we're going to have a

problem

now let's take a look and see what just

the speaker looks like

and then we'll see what happens when we

add in the speaker and the sub

now we can see when we add in our

speaker we're not creating any major

phase changes to the response which is

exactly what we want those two things

are summing really nicely together and

they're not fighting each other

so now i want to add in the measurement

of our speaker and the phase flipped sub

if we take a look at this we can start

to see a huge phase shift occurring

this is an indication that those two

sources are not aligned well and that we

have a problem so the ways that you

could go about fixing this would be to

either move the sub to a new position in

the room

or to flip that face switch in this case

if they're not perfectly 180 degrees out

of phase moving the sub to a new

position or moving your speaker to a new

position is going to be the best way to

get those better aligned

let's take a look at a couple different

measurements here that really clearly

show sbir or speaker boundary

interference response

these reflections are off of boundaries

either like your desk or your wall or

your ceiling and they can cause really

big dips or peaks in your frequency

response

i've got a couple of measurements here

that i took in our demo room our first

measurement had panels on all four of

the walls and then the second

measurement i took those panels off of

the front wall so we could see what

would change when we remove those panels

our red response here has panels on all

four walls and then our green response

with this big dip in it doesn't have

panels on the front wall

so as we can see we got this big change

around 240 hertz in our frequency

response and then we also had a bit of

an increase in the low end at 68 hertz a

room mode

and another increase in variation here a

little bit higher up in the 400 range so

right off the bat from the frequency

response we can see things are getting

worse without those panels on the front

wall behind the speaker to get a better

sense of what was happening in the room

let's take a look at our energy time

curve and see if we can find those

reflections that are causing the change

in our frequency response

again we have the red measurement which

did have panels on the front wall and

our green measurement which did not have

panels on the front wall

and right off the bat here we can start

to see some really big variations

between these two measurements our green

measurement has more reflected sound in

this very early range around three to

six milliseconds and then again here at

eight milliseconds and then as we move

later on in time we can start to see

some really big peaks in energy here so

we've got these two and then later on as

well around 21 22 and 23 milliseconds we

have these big spikes and again a little

bit later and these are all contributing

to those changes that we saw in the

frequency response

this allows us to figure out exactly

where this reflected sound is coming

from sound travels just about one foot

for every millisecond so we can figure

out that if this reflection here

occurred 11 milliseconds after our

initial sound source that this sound or

this energy had to travel an additional

11 feet we can then map out in our room

either on a piece of paper or with take

a string and figure out you know which

surfaces or which boundaries it could

have bounced off of that would fit that

11 millisecond range then we can put a

panel there to test and see if that's

the area of the room that we actually

need treatment in with a little testing

and use of the energy time curve or your

impulse response measurements you can

really fine tune your panel placement

and make sure that your all of your

early reflections are well treated

here i've got another example of speaker

boundary interference response or

reflections occurring in a room so this

is that same room but now i reconfigured

the treatment and the panels in there a

little bit

our first measurement the blue one here

has two panels right in the middle of

the back wall in the room and then our

second measurement here has those two

panels removed and placed on the floor

in between the speaker and the

microphone so we can see some pretty

interesting things happening here our

first measurement very clearly has a

spike in energy

right around four milliseconds

very quick after our initial sound

source and then our second measurement

the measurement that doesn't have the

panels on the back wall anymore has a

big reflection

or has two big reflections at 15

milliseconds and 16 milliseconds so we

can pretty easily take away a couple of

things here one our floor reflection is

obviously happening at 4.3 milliseconds

because as soon as we put two panels on

the floor we were able to get rid of

that and then in doing so we had to take

those two panels that were in the middle

of the back wall and put them on the

floor and then we created this big

reflection at 15 and 16 milliseconds so

now we know where in time our reflection

off the back wall is occurring and where

in time our reflection off the floor is

occurring for reference this room's 14

feet deep and our measurement microphone

was 5 foot 5 inches away from the front

wall

so that means our reflected sound would

have to travel past that microphone

hit the back wall and then bounce back

and if our mic was five foot five inches

away from the front wall it was just

over eight feet away from the back wall

which means we would expect to see that

reflected sound occur right around 16

milliseconds or a little bit over 16

milliseconds which is exactly what we're

seeing here so that's how you can figure

out using your energy time curve or your

impulse responses which boundary or

surface in your room your reflected

sound is coming off of

so we have another set of measurements

for us to analyze here and these were

taken in a room that was really well

treated so our first measurement shows

that room fully treated and then the

second measurement that we're going to

look at shows the same room but with the

cloud removed and i'll flash a picture

up on the screen here so you can see

what that room actually looked like with

all the acoustic treatment in it so i

have our waterfall plot pulled up here

and this is the room with the cloud as

well as the rest of the treatment you

can see a really nice even decay across

the frequency spectrum and a pretty even

overall frequency response with only 1

48 smoothing on this if i switch over to

our second measurement without the cloud

we're going to start to see a really

massive change here starting around 300

hertz or so we can see all of these

echoes occurring in a much longer decay

across the frequency spectrum so this is

just from that sound bouncing back and

forth between the floor and the ceiling

in that room as that cloud was removed

and the rest of the room was really well

treated there was a really prominent

flutter echo that was created because we

had a very well treated room and then

two very reflective parallel surfaces

that were left and we can clearly see

that here in the waterfall plot let me

switch back over to the untreated room

again so you can see this gets really

well cleaned up and then if we flip back

over we've got the flutter echo that's

very clearly seen here as well as this

increased decay time down here and i'll

leave the cursor here and switch back

over so you can see that again

clearly a very large change in both the

decay time of the room and cleaning up

that flutter echo and that's just the

difference that one cloud can make to

give you a more complete sense of what

these measurements look like with and

without that cloud let's take a look at

the etc the rt60 and our frequency

response so right off the bat we can see

a big change in the overall frequency

response we've got this big null that

was created around 120 hertz and we've

got two peaks above that that we also

see introduced to the frequency response

i'm going to remove the measurement that

doesn't have the cloud in it and smooth

this measurement to one-third so we can

take a look and see what kind of

variation we have in the frequency

response of this measurement as i

mentioned earlier the standard for the

best studios in the world or ebu

critical listening environments is plus

or minus 2 db with 1 3 smoothing and

then really great home studios fall

typically between plus or minus 5 db and

that's all with one third smoothing on

let's take a look and see how this room

is performing so i'm going to right

click on our peak here while hitting

control and then scroll down

to the lowest point in our measurement

and we can see that we've got a

variation here

that's about six or seven db so plus or

minus three plus or minus three and a

half db so like i said

achieving a really great home studio is

pretty attainable there's around four

thousand dollars worth of acoustic

treatment in this room but it's just a

regular bedroom it's 14 by 11 feet with

an eight foot ceiling so you can

definitely turn that extra room in your

house or your bedroom or whatever it may

be into a really great sounding room

alright so

here we've got the energy time curve

pulled up for this measurement and

the difference between these two is

pretty wild and striking

like some of the other graphs with and

without treatment that we've looked at

before this green measurement without

the cloud very clearly shows where these

reflections are occurring

like we saw that reflection off the

floor this reflection off the ceiling

now is right around four milliseconds

and if you have an eight foot ceiling

and your measurement mic is at four feet

you would expect those to be pretty much

at the same point in time so that makes

perfect sense and then these later

reflections here that we're seeing are

going to be what we saw in the waterfall

plot as that flutter echo where it's

pinging back and forth a lot so if i

highlight our red measurement here we

can see just how different these two are

and really pinpoint where that new

reflected energy is occurring over time

in the room last thing i want to look at

with these measurements is the reverb

time so i have our t20 pulled up here

for this room with the cloud and then

i'm going to add in the same t20

measurement but without the cloud

so adding in that t20 without the cloud

we can start to see that our our reverb

time not only got more inconsistent but

also increased quite a bit and

like i said earlier our main goal with

reverb time is to have it be as even as

possible so we don't have any big jumps

from one band to another like we see

here and then also here down below

utilizing all the different measurements

within our aw we can really start to get

a complete picture of what is happening

in the rooms and how we can improve the

sound in those spaces either by moving

acoustic treatment or adding new

treatments that are better suited to the

needs of the room

well i mentioned that the spl or

frequency response measurement was not

my favorite it does particularly excel

in one area and that is taking a group

of measurements and comparing them

directly to one another so that we can

see how the overall tonal balance of the

room is changing so here i have a

measurement set pulled up with seven

different speaker placements that i

tested and we're going to take a look

and see which one performed the best and

how those vary from one location to

another so with all seven of these

measurements piled up on top of each

other in the overlays it's a little hard

to tell what's going on so let's clear

them all out

and then we'll pull in our first

measurement

now these were all taken in an untreated

room

so things are pretty all over the place

but is a great way to see the room's

overall response and how we can start to

even things out just by moving our

speaker and listening position locations

so here's our first measurement and this

turned out to actually be the best

measurement in the set it's got a

response that's around plus or minus 9

db as we start to add in our other

measurements sometimes things were

pretty close to this and other times

they were quite drastically worse so

with b right off the bat we can see a

pretty big variation

in just these first two measurements and

this was just moving the speaker a

couple inches

the peak from our mode came down here a

bit but the nulls that we have up above

that

dropped way down adding in our c

measurement now we can see what that new

speaker placement is adding and again

we've got basically the same changes

from a to b we've got the room mode peak

coming down but then we've got that null

so it's a little bit better than b but

still doesn't quite have the overall

balance that we had with a now let's add

in that d measurement

so here we've got a response that's much

closer to what we had with our initial

response that a measurement so things

are definitely more balanced out than

with b or c

but doesn't have any real improvements

over a so let me go ahead and hide c and

b so we're just looking at the two best

measurements now and we can see a little

variation overall but

very similar shapes to these two

measurements and nothing really too

striking that makes one of these

measurements significantly better than

the other so continuing on with our

comparison let's pull an e here

and we can see again this jumps kind of

back to that b and c so slight change of

the room mode response around 80 db but

again we've got this huge null now at

126 hertz or so

and if we add in f

we can actually see a very similar

response but even worse so now this is

off of our graph so let me adjust my

measurement here so we can get the whole

picture and if we go ahead and plot our

the variation of this we're up we've got

a variation of over 30 db or so that's

plus or minus 15 db and if we compare

that to a we're at plus or minus 9. so

just by improving our speaker placement

and listening position locations we

evened out the response in this room by

6 db which is pretty incredible so we

finally made it i know this is a long

video but i truly hope that it helps

give you a better understanding of

acoustic measurements rew and how you

can use acoustic measurements to improve

the sound in your studio if you liked

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