Looking for example broadband resonator designs

My (nearly done) studio is 12'6" x 22'5" x 7'5.5", with a soffited wall at the listening end, and bass hangers at the opposite end, closed in by wall. That wall I'm turning into a full-wall resonator. The depth is a standard stud depth and the back of the wall is sealed up. I calculate that I need to manage 116hz and below, particularily from 80hz and down, but given the presence of bass hangers and corner bass traps, I think (correct me if I'm wrong), that I should start by trying to tune the resonator in the 125hz -> 60hz range? Can someone suggest how to approach designing a broadband resonator to cover this range? Many Thanks, Shaun McArthur

have you checked out the slot resonator calculator spreadsheet in the stickies? also, the Chris Whealy control room calculator and absorption calculator spreadsheets are quite useful as well. that said, you'll find that getting sufficient depth of the air cavity will be required to get low frequency performance. can you post a diagram and/or photos of your space so we understand the construction and layout better?

Thanks Glenn - I'll check out the calculators. It's a straight forward layout - just a long room with sofit walls at the front, pretty straight forward.

Shaun - a standard resonator won't go below 100hz in reality, they are more suited to the low mid section 150 - 500hz.

Thanks for replying john. As the depth is necessarily constant, is the trick to designing something like this keeping the gaps constant and varying only the widths of the slats? I'm a bit stuck and have to solve this to keep things moving. Cheers, Shaun

have you measured the room response yet? you might want to consider doing this before deciding what you need for any specific trapping. is the back wall closed or open? how are low frequencies getting to the bass traps behind this wall?

A fair question, but no, all by the numbers to date. The drywall just went up, so I should be in a position to start..how would you recommend proceeding, some pink noise and my best mic at the operator's chair? cheers, Shaun

using REW (or FuzzMeasure on Mac) and a Behringer ECM8000 is pretty common choice for this. if not any omni mic with a flat frequency response should do it. put the speakers in their approx position on stands (cement block can suffice) and use a boom mic stand to position the mic vertically at your approx listening position for data on that spot, and do another trace - put the mic in a corner and a speaker in the opposite far corner to get the overall room response.

Glenn - I went away and did some measurements. Admittedly pretty green at measurement & interpretation I did my best to setup some reasonable parameters for fuzzmeasure. I attached the freq response & rev time response graphs. - Fuzzmeasure & my ECM8000 were used. - pretty small room - 11'x20' - mic was placed at mix position, ear height I really have no idea how to interpret this properly, so would appreciate any input you could provide. The room is almost 'finished', but there's still time to make adjustments if you think some would help. Best in the new year, Shaun McArthur Riverhouse Sounds

one thought - it might be possible if you export the measurements as an FRD or ETF (or REW) compatible file i can directly import it and use it. if not, could you post some waterfall graphs and the ETC graph?

Sure can. I'll get that together tomorrow.

I performed a soundcard config, an SPL reference and then checked levels and did some measurements. I kept getting a 'Low Level' warning in blue text no matter what level the monitor were at. I've attached what I think are the files you need. It's really hard to tell if my ECM's signal is routed to REW properly. Also - the program seemed to be only using the right speaker.. Best, Shaun

do you have the system setup per the REW instructions including the loopback?

Yes - I'll attach it once I'm home.

Here's the .cal file.