I'm considering building DIY room treatment panels using Knauf fiberglass panels - I believe its the same material GIK acoustics uses in their panels, and sells on their website. I'm DIY-ing because I'm on the west coast and shipping from GIK/RealTraps etc is prohibitive (basically doubles the cost).
When looking up the panels on Knauf's website, I see that they are available in FRK or ASJ facing, or plain.
For a given density, the faced panel always has a higher sound absorption coefficient in the 125 Hz octave, and lower in the highest octaves.
for example, taken from this page: https://www.knaufnorthamerica.com/e...s-insulation-board/earthwool-insulation-board
looking at 3.0 PCF (48 kg/m³) board of 2 inch thickness, the sound absorption coefficients in a Type A test (flat against a boundary, no air gap, facing outwards) are:
Plain - 0.29
FSK - 0.67
ASJ+ 0.75
I don't understand why this is, so I'm doubting these numbers. Does anyone have experience with faced vs unfaced panels and noticed or measured significantly better bass decay time improvements with the faced panels? Do you know why the faced panels are better at absorbing bass?
The other potential benefit I've noticed is that the absorption coefficients are LOWER for the faced panels at higher frequencies, which prevents the room from being too 'dead' (as recommended on Amir's review the speakers I have).
eg the 3 PCF panels at 4 kHz:
Plain: 1.03
FSK 0.28
ASJ 0.24
Basically, Is it worth spending the extra money for the faced panels?
When looking up the panels on Knauf's website, I see that they are available in FRK or ASJ facing, or plain.
For a given density, the faced panel always has a higher sound absorption coefficient in the 125 Hz octave, and lower in the highest octaves.
for example, taken from this page: https://www.knaufnorthamerica.com/e...s-insulation-board/earthwool-insulation-board
looking at 3.0 PCF (48 kg/m³) board of 2 inch thickness, the sound absorption coefficients in a Type A test (flat against a boundary, no air gap, facing outwards) are:
Plain - 0.29
FSK - 0.67
ASJ+ 0.75
I don't understand why this is, so I'm doubting these numbers. Does anyone have experience with faced vs unfaced panels and noticed or measured significantly better bass decay time improvements with the faced panels? Do you know why the faced panels are better at absorbing bass?
The other potential benefit I've noticed is that the absorption coefficients are LOWER for the faced panels at higher frequencies, which prevents the room from being too 'dead' (as recommended on Amir's review the speakers I have).
eg the 3 PCF panels at 4 kHz:
Plain: 1.03
FSK 0.28
ASJ 0.24
Basically, Is it worth spending the extra money for the faced panels?