Room Acoustics - Bass

[DrewRob]

I'm in a 8' X 9' square room.

My desk is placed against the wall facing down the longer side of the room and I have two KRK studio monitors positioned towards me where I sit in the center in a triangle formation.

However...I cannot hear the thickness or "rumble" of the bass unless I sit back as far as I can against the opposite rear wall. Is there any type of acoustic treatment that can allow me to hear this rumble from my normal sitting position or is it just because of the nature of the lower frequency sound waves?

Thank you for your assistance, please let me know if there is any additional information needed.

 

[bandcoach]

room height? with that I can give you a resonance profile of the room and offer some guidelines on developing some low end treatment

As for the rest, it is just a case of propagation time - this is directly related to wavelength which is inversely proportional to the frequency - the lower the frequency, the longer the wavelength, the longer it takes for the sound to develop and vice versa

basically anything under 72Hz or thereabouts is going to be hard to hear directly as the room is shorter than the wavelength.

Also, I understand your issues with having a small, boxy room meaning your desk is against a wall, but it is not the ideal situation for what you are trying to do

 

[DrewRob]

Thank you for the response!

The ceiling is roughly between 8 - 8 1/2'

Relocation would probably be ideal, but I have to work with this for now.

 

[bandcoach]

Assuming 8 1/2' room height, basic room resonances are:

Axial - along dimensions
h	w	l
66.47	70.63	62.78
Tangential - across two dimensions
hw	hl	wl
199.41	211.89	188.34
Oblique - at the corners (where all 3 dimensions meet)
hwl
332.35​

you need to pay attention to the whole multiples of each of these frequencies as well, as there are several nasty reinforced nodes as you move through the first 20 multiples and up

e.g. up to 1kHz these additional reinforced nodes are

1st Node	2nd Node	Freq
L 3	WL 1	188.34
H 3	HW 1	199.41
HL 1	W 3	211.89
H 5	HWL 1	332.35
L 6	WL 2	376.68
H 6	HW 2	398.82
HL 2	W 6	423.78
L 9	WL 3	565.02
H 9	HW 3	598.23
HL 3	W 9	635.67
H 10	HWL 2	664.70
L 12	WL 4	753.36
H 12	HW 4	797.64
HL 4	W 12	847.56
L 15	WL 5	941.70
HW 5	HWL 3	997.05

 

[DrewRob]

Thank you for taking the time to assist me with my questions, but how can I take this information and use it for my room? I am unfamiliar with this terminology.

 

[bandcoach]

The first table has the base frequencies at which your room reinforces sound. the second table shows where these base frequencies overlap higher up to produce unusual resonances - i.e. it shows how the frequency response of your room is affected by all three dimensions.

These frequencies should be the target of any treatment you apply to your room, mostly n the form of diffusion and absorption.

For more insight see this John L Sayers recording manual - read the pages linked on the right hand side