Hi Ethan! Hi everyone! Great Forum! This is my first post and would like to ask for advice.

My room H,W,L = 6.5', 5.5', 7.5' which i use basically for mixing rock/pop projects is 100% covered with egg crate type foam (sorry they were installed before reading Ethan's articles!) and the floor is carpeted, this radical treatment was recommended by an acoustic tech because of the room dimensions. I read Ethan´s web page "Acoustic Treatment" article which i find very interesting and would like to ask the experts for advise in terms of adequate bass traps and their correct placement for this type of room to obtain the best frequency control. Are diffusors suited for this room? if so where to put them.

My room's specs:



The 705's are powered by a hafler P4000 amp and mounted in stands with the tweeters at ear's height, i choose them because of their flat frequency response and limited bass extension to interact friendly with the room. They sound great but the "lower bad modes" have to be controlled to get tighter bass an clearer low-mids. The computer and processors are located under the desk.

This is the 705's anechoic frequency response graph.



The red line refer's to the bass port blocked with foam pads.


Ethan, for the dimensions and information given, can you comment about the sonic behaviour of this room and the best way to improve it acoustically??

Thank you very much for your kind advise!

Enrique.

Hi Enrique,

Welcome to the forum.

> this radical treatment was recommended by an acoustic tech because of the room dimensions. <

I agree that a room so small needs to be pretty dead. Small room ambience is always bad ambience, and that room is really small.

> would like to ask the experts for advise in terms of adequate bass traps and their correct placement <

Rigid fiberglass or mineral wool panels, at least 3 or 4 inches thick, straddling as many corners as you can manage. If you line every single wall-wall corner from floor to ceiling, and every wall-ceiling corner all around, that will make a very big improvement.

> Are diffusors suited for this room? <

No, sorry, it's too small.

--Ethan

Thank you very much Ethan! I'll follow your advice precisely!

Enrique.

Hi masters! Here are the results after placing the mineral wool panels wrapped with fabric and straddling the ceiling-wall corners and wall-wall corners. The overall low level behaviour improved slightly in a more neutral way.

Here is the frequency response of my room measured at the mix position using the radio shack spl meter as microphone connected directly to the converter to record Bob Katz's site full band pink noise and a wavelab-generated sine wave sweep from 30 to 1100 Hz

Blue = Room response
Red = BK Pink noise
Green = sine wave sweep



Listening to some reference cd's the most disturbing frequencies are the 157Hz peak an the 125Hz dip. I'm planning to build a Helmholtz resonator tuned to control the 157Hz peak.

1) In your opinion comparing other room's response, is this too way out of the line for general rock mixing duties? Or should i stop being so technical and go right now for the killer mix!

2) Where is the most effective place to hang the resonator?

3) What to do with the 125 and 419 Hz dips? Honestly i don't have a clue!

I'm standing by for your advice on this.Thank's!


Enrique.

Consider replacing some more of the foam with some 2" 703 or similar. This will help broaden out the absorbtion a bit more.

After that, you need to figure out WHY you have those nulls and what dimension(s) are causing them and then deal with it accordingly.

Also, have you played with speaker/seating position to help smooth things out? You don't mention where you're sitting.

Bryan