This week we finally took some time out from actual recording sessions and assigned ourselves to the maintenance and improvement tasks that have cropped up over the summer, the priority being the creation of some proper acoustic baffles! We’re so happy the results, and the price, at around £60 each, that we thought we’d share how to build your own acoustic baffles.
For months we’ve been using some concave boards we rescued from a studio that was closing. They did the job of creating a smaller space within our live room, or isolating one sound source from another, but they also introduced their own negative acoustic properties, mostly a kind of boxy reflection, because their construction was too thin, lightweight and had poor absorption.
Having looked at other homemade baffle solutions I feel like most of them would introduce similar acoustic issues based on the choice of materials and, usually, a lack of overall depth.
We’ve been thinking for months about the best design for the acoustic baffles and eventually we hit on the idea of using a bookcase and filling it with appropriate acoustic material. The benefits of which are:
- The shell is a pre-designed bookcase that just needs fitting together IKEA style.
- It will support itself – no potential for DIY failures.
- Both sides will be acoustically treated, not just one – assuming the bookcase has no wooden/cardboard back the treatment will run all the way through.
- Bookcases are about 7ft tall and 2-3ft wide, which is about the perfect size.
Our plan was to build three of these baffles so we can create a ‘U’ shaped vocal booth. The great thing about this modular design is that we can increase the size of the booth, to adapt the acoustic properties to individual singers, by opening up the angle of the side panels creating a flat bottomed V shape ‘\_/’. We also have a two tiered roof in the live room, one just over 7ft high and one around 11ft high – so we can dictate the ceiling height of the booth also.
Check out the build diary for the full details and leave a comment if you have any suggestions to make them better!
Buy three Billy bookcases from IKEA and build them
Source the appropriate acoustic treatment
We headed down to SIG Insulation and bought a roll of earthwool to help absorb higher frequency sound, and also a pack of RW3 rockwool cut into eight 5cm thick panels. RW3 is a denser material and should absorb a different, lower set of frequencies, helping to create a more acoustically balanced baffle.
We cut the hard rockwool panels to the size each shelf area to create a spine of dense material running through the baffles and packed the earthwool treatment on either side, filling the shelves entirely.
- Someone with a background in acoustics could probably make better informed decisions regarding the exact acoustic materials and how to pack the shelves. If you’re that person then please leave a comment and I can include the recommendations in this blog.
- 5cm thick rockwool is almost definitely not thick enough to absorb frequencies below 200hz. However, a thicker slab would be hard to fit in, without losing out on the earthwool partitions. We’re hoping the 5cm rockwool slab does well enough within the average vocal range and aren’t expecting it to influence frequencies below that.
- The earthwool we sourced came as a pretty thick roll. We had to press it into the available space. I had hoped for more air gaps between the rockwool and earthwool partitions. It would have been possible, but messy and time consuming, to slice the panels thinner but we chose not to. Looking back, I’d try to buy a thinner roll of earthwool.
Source fabric to cover the front and back of each bookcase
We popped in to our local fabric shop, Abakhan Fabric in the Northern Quarter, and found a roll of black material that suited our needs and didn’t result in much waste. Back at the studio we cut it into shape, leaving about 5cm extra height and width to create a hem. We stapled it to the bookcase edges, hemming as we went.
- We managed to make our ‘hem as you go’ approach work pretty cleanly but if you, or someone you know, can use a sewing machine it would be way smarter to have them sew hems into appropriately measured sheets of fabric. It’d be a simple case of lining it up and stapling then.
Source some recessed speaker cabinet handles and fit them
Once the fabric goes on it’s not possible to grab the shelves so we decided to fit some handles. Particularly, we opted for recessed handles so we can still stand the bookcases right next to each other when not in use.
Use a Jigsaw the cut the appropriate hole, scoop out a bit of the insulation, and screw handles on.
- For the most part the Jigsaw didn’t pull at the already in place acoustic treatment. However, it will be better if the handle fitting stage is done earlier, before before the acoustic treatment is placed on the shelves.
- Total build cost is about £60 each.
- For a DIY job these baffles look pretty smart.
- They’re strong and easy to move but;
- the acoustic treatment is still thick and substantial.
- But best of all they sound great! Our live room is well treated anyway but it is noticeably different standing inside the ‘U’ shaped modular booth. The vocals are more isolated and there are far less audible reflections.
- They do a great job of separating sound sources.
- When not in use they can act as room treatment on walls/doors that are not already fully treated.
- The only design choice I’d improve upon, that hasn’t already been mentioned, would be to attach metal braces diagonally across each corner of the bookcase. This would strengthen the unit more. However, having moved them about over the last couple of weeks, they’re pretty solid as they are.