Finally finished mounting all absorption panels and the corner bass traps in my studio. I did some measurements to check the effect of the acoustic panels on the overall acoustics of the room.
I took four readings. The base line reading was taken in the room with only the ceiling panels and the side wall panel in place. I took the second reading with the corner bass traps installed, 57 cm from the floor. The third reading was taken with the corner bass traps 110 cm from the floor and 20 cm from the ceiling. The last reading was taken with both bass traps and 3 panels behind the monitor speakers and computer screens. Here are my findings.
Here is the overall response of the room (SPL) for all readings. Placing the corner bass traps really helped a lot so that was a good investment.
Zooming in on the frequencies between 20-600Hz shows not much overall improvement in frequency response. I tried lifting the corner bass traps so they were twice as high above the floor and that enhanced the response a little bit.
This diagram shows the group delay characteristics. As you can see, installing the absorption panels helps a lot in levelling the delay response.
Acoustics: Group Delay 20-20000Hz
RT60 is the time required for reflections of a direct sound to decay by 60 dB below the level of the direct sound. The effect of the absorption panels nicely evens out the response above 200 Hz and drastically cuts the delay time for frequencies below 200 Hz.
Base line spectrogram of the room with ceiling panels and side wall panel only.
Spectrogram with corner bass traps in place (57 cm above the floor).
Spectrogram with corner bass traps in place (110 cm above the floor).
Spectrogram with all absorption panels in place. Looking at this spectrogram I can only conclude that without the panels on the front wall the response is even a bit better. The cause of this could be the back wall where a cabinet with glass doors (reflective surface!) is situated.
Conclusion
The installed panels really help optimising the acoustics of my studio room, especially concerning reflections and reverberation times. There is still room for improvement, some panels on the back wall would certainly help I think and adding two corner bass traps to the back wall. However, as my room is rather packed as it is, there is no room for more bass traps so I’ll leave it like it is for now…