How to Use Room EQ Wizard

what's up everyone graham here with

music city acoustics and we're talking

all about room measurements do you know

how to take measurements of your room or

how to analyze those measurements

looking at waterfall plots frequency

response graphs impulse responses decay

times and more

in this two-part series we're going to

show you step-by-step how to take

measurements of your room using room eq

wizard a completely free and super

powerful software program and then we're

going to show you how to analyze those

measurements so you can build an action

plan for improving the sound in your

studio

so more than likely you have just about

everything we're going to need to get

started you need your computer an audio

interface with at least two channels

your speakers cables to hook everything

up together a microphone stand

tape a tape measure and then we need a

couple things more specific to taking

room measurements we need a measurement

microphone an spl meter and of course

room eq wizard when it comes to

measurement microphones you don't need

to spend a lot of money we've got this

bearer dynamic mm-1 it's a couple

hundred dollars but there's a ton of

great options out there for around 100

bucks the most important thing is to

make sure when you're buying a mic that

it comes with a calibration file it's a

file that you should be able to download

after you've bought the mic that will

tell rew the exact frequency response of

your microphone and then the same thing

applies for your spl meter you can

either get one right on your phone for

free or you can buy a standalone one

like this our checkmate cm 130. we've

got links to both microphones and spl

meters down below so check those out

now that we know what gear we're going

to need let's download rew onto the

computer and get started so on my roomy

qwizzard.com

clicked on the mac os download i'll go

ahead and get that installed and we're

going to open it up

so all the default settings for the

installer will work great and then as

soon as we click finish

rew is going to open up

so we've got rew pulled up it shows you

the user manual the first time you open

it and rew is a

really comprehensive powerful tool and

the user manual is very well written and

has a ton of great information about

acoustics and measurements uh and the

different ways that rew is actually

taking those measurements so if you're

curious about any of it definitely check

it out it's an awesome resource

for now i'm going to go ahead and close

the manual

and then we will go ahead and get our

audio inputs and outputs set up we're

going to do that under the preferences

tab so i'm going to go up here in the

top right to this wrench and that will

pull up our preference window and from

here you can select your interface

your sample rate the inputs and outputs

that you want to use and then we'll be

able to calibrate our sound card from

here so i'm going to go ahead and select

my duet for both the input and the

output and then i'm going to change my

sample rate to 48k

you can use either 441 or 48k whatever

you're working with will be totally fine

here and then i prefer to use the left

output and left input

for my system that's just because i

think of those as one either one works

works just fine

we don't need to change anything here in

the

input or set output channel mapping

controls and that leads us to this sound

card calibration

so now we're ready to create a sound

card calibration file for your interface

this allows rew to measure identify and

then remove any potential artifacts or

distortion that your interface might be

imparting on the measurements otherwise

to calibrate your sound card you need to

plug the output of your interface

directly into the input of your

interface

so once you have the output of your

interface plugged into the input of your

interface we're ready to hit calibrate

sound card

right here rew is just telling us a

little bit more about the loopback that

we created and how it's measuring the

frequency response we're going to hit

next through that so as we'll see right

here it's telling us we want a fairly

high level between minus 12 and minus

6dbfs

right here is going to be the output of

your audio interface and right here is

going to be the input and we want to

make sure that the input is coming in

around minus 12 to minus 6 db so let's

hit next

and then you should start to see signal

pop up so again this is the output and

here's the input so mine's looking

pretty low so i'm going to go ahead and

turn up the output of my interface this

is the same way that you would turn up

your speakers if you were listening to

something

so i will start adjusting this and we

should see this level come up

so once it's showing minus 12 or right

around minus 12 to match the output i'm

going to go ahead and hit next so we'll

hit next one more time

and rew is going to start taking a

measurement all on its own

we can see that happening here so this

is the measurement that it's going to

use to create the calibration file for

your interface so if we hide our

preferences for a second

you can see the measurement that it took

and it should look something like this

where it's relatively flat your

interface should not be imparting a lot

this is just a stop gap to make sure

that any you know frequency response

changes or variations that your

interface does have aren't going to

impact your measurements so we'll bring

this back up and the last step in this

process is to hit make cal file

you can enter any notes you have and

then you want to make sure you go ahead

and save that somewhere so you can pull

that back up anytime you need it so

we'll name this duet

cow file

i'm just going to go ahead and save that

on my desktop

so rew should have automatically loaded

in your calibration file that you'll see

right here if that doesn't happen for

any reason go ahead and hit browse you

can search your computer for it from

there

the last step that we need to take

before we can start making some noise is

to load in our microphone calibration

file

double check what your input settings

are here so duet usb microphone is mine

and i'm going to go to the cal files tab

here

and then i'm going to find duet usb

microphone and this is where we want to

load in the calibration file for your

microphone i'm going to hit browse and

then i already put in that rew folder

that i created

the calibration files that i got from

bearer dynamic so you'll see here i have

two different calibration files i have a

zero degree one and a 90 degree one and

they have to do with the orientation

that you're gonna have your mic in when

you're taking measurements i like to

take my measurements in the 90 degree

position or with my microphone vertical

the reason for this is that you get a

flatter frequency response out of the

microphone when you orient it

horizontally you get a buildup of

pressure at high frequencies when it's

pointed directly at the speaker if you

don't have both calibration files this

isn't a huge deal it is mostly just a

difference that occurs at really high

frequencies and most of what we're

looking at in our measurements is going

to be lower in the frequency range and

then the whole reason for this

calibration file is that every

microphone has its own frequency

response and if we know what it is rew

just like we did with our interface can

eliminate any interference or variations

that the frequency response of your

microphone might otherwise impart on

your measurements

now that we have calibration files for

both our microphone and our audio

interface we need to calibrate the input

level into rew to do this i'm going to

open up the spl tool

this allows us to move the microphone or

our speakers and to compensate for the

level changes that those might introduce

so that we can compare apples to apples

different listening positions or

different speaker placements and know

that what we're seeing is the change in

placement and not just a change in

distance from our microphone to our

speakers for all my measurements i like

to use 80db c weighted for my reference

level this makes sure that i have a good

signal to noise ratio and that

background noise won't be a problem with

any of my measurements so let's jump in

and i'll show you how to calibrate our

input level we're ready to start making

some noise i've got my measurement

microphone my spl meter and the spl tool

pulled up here in rew i'm going to go

ahead and click on calibrate here

and that will pull up this dialog box

that says choose signal source

i'm using a speaker for these

measurements instead of a sub so i'm

going to go ahead and select speaker cal

signal and then we're going to hit ok

as soon as you hit ok rew is going to

start generating a signal so make sure

your interface is turned down before

starting this

so take your spl meter and hold it right

next to your measurement microphone the

target here is to get the level on the

spl meter to read 80 db

so my spl meter was reading right at 80

dbc but i wasn't getting any signal from

my microphone so i got this warning here

that says the input level is too low if

this happens just make sure phantom

power is turned on or like in my case

that your mic gain isn't turned all the

way down so i'm going to go ahead and do

this process one more time

so with my mic gain adjusted i was able

to get a signal coming through there and

now everything's ready to go now we can

go ahead and close out this spl tool

any time that you move your microphone

or your speakers just pull it up and

recalibrate things real quick so that

every measurement you take has a

consistent reference level

we're finally ready to start taking

measurements i'm going to go up here to

the top left corner and hit measure

that brings up the measurement window

there's a lot of options here so let's

walk through everything and then we're

going to be ready to start taking

measurements

so the first thing i want to do is name

my measurement

the note section is super useful for

putting in any info about the

measurement that you're taking so

anything like microphone placement or

speaker placement if it's the first

listening position you're testing or the

second listening position

so right below notes we have the range

and that's going to be the starting and

ending frequency for your measurement i

like to have my measurements start

typically at 15 hertz so just below what

we can typically hear and then going up

to 20 000 hertz is fine for the level i

just leave this at -12 that's what we

calibrated the system at and everything

should be working great there up here in

settings we have the length of the sweep

that rw is going to take and the number

of repetitions

i prefer to set this to 512 and at least

two repetitions the more accurate that

you want your measurements to be the

longer the sweep should be and the more

repetitions that you should take so that

rew can average those out and provide

you with a more accurate result of

what's actually going on in your room

for our basic measurements we don't need

to change anything here in timing under

protection we'll leave abort of heavy

input clipping occurs the next thing

that we need to adjust is the delay

setting here i like to push this up to

around six seconds so that when i hit

start measurement that measurement

doesn't actually start for six seconds

that gives me time to move away from the

microphone or to leave the room so that

i'm not interfering at all with the

measurements that i'm taking the last

thing that we need to check on is our

output and input settings your input

settings should stay pretty consistent

so your output settings will change

depending on whether you're measuring

your left speaker or your right speaker

or both i'm going to start with my left

speaker so we're going to leave this as

it is but if you click on this you can

change it to your right speaker or your

left and right speakers and then you can

take different measurements depending on

what you're going for our calibration

files are already set in our preferences

so we don't need to do anything here but

if you click on it you can just double

check that everything's loaded correctly

now we're ready to take our first

measurement all we have to do is hit

start and rew will do the rest

[Music]

so we've got our first measurement

pulled up here in rew and the first

thing we're going to do is save it to

make sure we don't lose anything to save

all the measurements in your rew window

hit save all

you can add any notes that you want

and then you can name it and choose

where it's going to be saved

now you've got your measurements saved

you'll be able to pull them up anytime

or you can also send them off to us if

you're looking for help with your room

we're happy to help you analyze them and

give you input on how to treat your room

before we wrap this up i want to talk a

little bit about what those measurements

should look like and the expectation

levels that you should have for your

measurements so to give you some context

the best studios in the world have a

frequency response that falls around

plus or minus 3 db and the best home

studios have a frequency response that

normally falls between plus or minus 5

db sometimes even a little bit higher so

there's going to be a pretty wide gap

from top to bottom in terms of your

frequency response and that's totally

normal let's take a quick look at the

measurements we took here in my office

and i'll show you a little bit more

about that

so i'm going to quickly hide our phase

mic cal and sound card cal so we don't

need to be viewing those

and then we're going to zoom in here a

little bit on our measurement so i'm

going to change these limits in the top

right corner i'm going to drop this down

to 100 and then pull this up to 50. and

this is basically just going to zoom in

our measurements and we can see here the

bottom level in my office is around 72

db and excluding this big peak here the

top level is right around 90 db so it's

about a plus or minus 9 db

range for my frequency response that

gives you 18 db from top to bottom from

our lowest level to our top so that's

quite a bit and we will definitely want

to see that smoothed out if we were

treating the low end in here for a room

that doesn't have any low end absorption

or any bass trapping in here you should

expect to see some pretty crazy uh jumps

from the bottom of your graph to the top

of your graph and that's totally normal

it just means this office has a lot of

room for improvement if we were trying

to turn it into a mixing room

in part two of our series on rew we'll

walk you through how to analyze your

measurements and break down what's going

on in your room we'll take you through

waterfall plots frequency response

graphs impulse responses decay times and

even the room simulator in rew i hope

this video was helpful and gives you a

jumpstart on taking measurements in your

room if you liked it please like and

subscribe to our channel and we'll see

you in the next one