The Mixing Environment and Critical Listening

Question 1

Give the four aspects of a mix that can be affected by the acoustics of your mixing environment (and how):

Answer 1

Frequencies - a poorly/unreated room will emphasise and de-emphasise certain frequencies, causing you to cut and boost those frequencies unneccessarily
Dynamics - Reflections and resonancesmake it hard to accurately judge the dynamic processing needed
Spatial - Reflective rooms add their own ambience and ‘room sound/reverb’ that could lead to the false impression of space in the mix
Imaging - The L/R balance and imaging in general can be thrown off in a poorly treated room

Question 2

Name the two main types of nearfield monitor:

Answer 2

Infinite baffle (sealed box) and Bass Reflex (ported)

Question 3

What are the advantages of Infinite Baffle monitors?

Answer 3

The bass rolloff slope is relatively gentle, therefore the will actually be a better sub-bass response compared to bass reflex systems that have a steep rolloff curve.
There is also better transient response at lower frequencies (a ‘tight’er sound) and less phase-shift

Question 4

What are the disadvantages of Infinite Baffle monitors?

Answer 4

Bass rolloff occurs at a higher frequency, leading to a lower percieved bass response

Question 5

What are the advantages of Bass Reflex monitors?

Answer 5

The low-frequency rolloff frequency occurs much lower than infinite baffle systems, giving a more impressive bass response and volume

Question 6

What are the disadvantages of Bass Reflex monitors?

Answer 6

The resonance of the low frequencies causes smearing of transients over time, making it difficult to properly judge relative levels of bass instruments on a poorly designed reflex system.
There are also relatively larger phase shifts in the low frequencies, impacting the naturalness of the low-end
The midrange can be less transparent than sealed box systems

Question 7

Why do the front and back of a speaker need to be seperated by a baffle i.e sealed-off from one-another?

Answer 7

To stop the negative soundwaves emanating from the back of the cone from interfering with the positive soundwaves coming from the front, which will cause frequency/phase cancellation and effect the efficiency of the speaker (especially at low frequencies)

Question 8

Why is the fact that ported monitor systems smear low frequency transients and cause phase shifting not a huge issue in-practise?

Answer 8

Because human hearing is less sensitive to transients and phase-shift at low-frequencies

Question 9

Why are the Yamaha NS-10s and Auratone 5Cs such a popular choice of monitor amoung mixing engineers?

Answer 9

They both have fast and accurate transient response due to their small cone size and infinite baffle design, and have an enhanced mid-range, making mixing inbalances in the most audible range of human hearing much more obvious.
They also lack LF resonances and LF ‘overhang’ therefore, giving a clearer representation of the envelope of kick and bass instruments.
They also reveal if the kick and or bass have been mixed in such a way as to be heard on and translate to smaller speakers that are most common in radios, cars, public places etc.

Question 10

Which shape of room will generate the most standing waves ?

Answer 10

Square

Question 11

Along which wall in a rectangular room should nearfield monitors be placed in order to achieve greater low-frequency monitoring; and which wall to gain greater mid-range accuracy and stereo imaging ?

Answer 11

Along the narrow wall for the former and along the longer wall for the latter

Question 12

What is an anechoic environment?

Answer 12

An environment with no reflections or reverberation

Question 13

What is RT60 and what does it measure ?

Answer 13

The time it takes for a sound to die-away by -60db, it’s the technical term for the reverberation ‘time’ of a space.

Question 14

Why does the RT60 need to be roughly the same across the frequency spectrum in a mixing environment ?

Answer 14

So that the room sound has a flat response and therefore will not colour the sound heard in the room, and therefore interfere with your assesment of a mix.

Question 15

What factors can colour the sound of your mixing environment?

Answer 15

The reflecivity of different surfaces and objects, and how they reflect and diffuse different frequencies to differing degrees; the presence of standing waves/resonances (determined by the distance between parallel-facing walls) and relative monitor placement.

Question 16

How many seconds is a good length of reverb (RT60) to have in your mixing room ?

Answer 16

0.3 - 0.5 seconds

Question 17

Why do standing waves occur in a room?

Answer 17

Any frequency whose wavelength is either exactly - or an exact multiple/division of two of - the distance between two parallel-facing walls (including floor and ceiling) will reflect that wavelength back into the room in-phase with the original, doubling it’s ampliude.

Question 18

Name three elements of a room’s ‘sound’ that need to be controlled/attenuated in order to create a relatively accurate mixing environment

Answer 18

Echo/reverberation - ‘slap’ echo can emphasise and create harshness in the mid to high frequencies and interfere with phase relationships in this range, confusing the stereo imaging
Standing Waves - interfere with the tonal balance of your mix,occuring mostly around the monitors themselves
Side reflections interference - reflections reaching the ears from the side walls will interfere with the direct sound reaching the ears from the monitors

Question 19

What is a ‘coefficient of absorption’ when considering materials for a mixing environment ?

Answer 19

It is a measure of how what percent of a given frequency will be absorbed by a material (measured from 0.01 - 1, with 1 meaning 100% absorption of the given frequency and no reflection)