About the best you can achieve but you need to pinpoint where to put these. I’d set up your monitors with the correct monitoring angles centred to the room - you’ll cause yourself grief having them offset to one side
his absorbers aren’t porous - they’re plastic bagged
It has more to do with the gas flow of the material rather than the density. If you have the space to use cheap fluffy fibreglass you will get more low-end absorption. This has worked for me seems to be a consensus for this over at Gearspace. Of course space can be an issue.
It is confusing, I've been there. I've watched some of Jesco's vids and read some of his free stuff. I'd recommend searching some of the threads on Gearspace relating to "pink fluffy" insulation.
I got great results with fluffy fibre at 18" and the air gap is not so important at such low gas flows......so I've read!
It’s about gas flow through the material and the amount of resistance imposed by the material before it reaches a reflective surface and then the resistance as it passes back through after reflection. That’s why the high density stuff has a much higher absorption coefficient at low frequencies compared to the low density. If the absorptive material can’t restrict the airflow, it’s not working - it needs to impede the flow of air to convert sound mechanical energy to heat - 3 layers of 35Kg/cuM Rockwool may have the same effect as 1 layer of higher density material at say 96Kg/cuM for the same sheet thickness and will maybe have a better gas flow impedance due to the distance travelled through resistive material but the size gets outrageous. I don’t see how lightweight glass fibre would be an improvement on heavier Rockwool. The compressed fibreboard I have compared to packed blanket in walls in several studio builds and on panel absorbers and to be honest it’s streets better.
This is one of the reasons to use the compressed sand/fibreglass board - webbed resin backing, cloth facing, you can just resin brush the edges to prevent shedding after cutting with a trimming knife. Rockwool and glass blanket shed continuously for their whole life as they sag under their own weight and the fibres break. I mentioned previously about opening walls that had originally been filled with blanket insulation and the top 1/4 of each chamber was empty - the blanket had been wired in place and glued to one inside face but it still just fell off.
Have you looked at the time decay (waterfall or spectrograph) for your room? The freq response is not bad if the decay time is pretty even, especially for that room. Have you measured with the door open or closed (think about how you will typically work)
Perfect - make sure to set up your monitors first. I use a tape measure and protractor to set the monitor equilateral triangle.
Do you have a brand / model for those boards? I haven’t seen cloth faced panels around here.
I agree about the plastic. He does have that effective depth across the corners. Some room dimensions never get much better without exotic solutions , but as long as the time domain is even, the room will yield excellent results.
I like to use a 1 or 2” layer of dense, like 703 or 705 or even Roxul 40 with fluffy behind it, if you have the space. Dense insulation loses its effectiveness after 8” or so and the density gradient and possible membrane behavior of the dense “face” adds more effectiveness. Plus the dense material provides a nice flat surface to back the fabric. I’m doing this treatment now. Front corners are 1m wide and .4 m deep with 4” Roxul 40 and fluffy behind. I used similar treatment in rear corners and we have excellent results. We also have a large 10” ceiling cloud and other first reflection treatments.
