Grasping Helmholtz slat resonator construction

[sonicsix]

I've searched and read as much as possible on building slat resonators to flatten some room responses in my mix room and live room. I was drawn to slat resonators to grab problem areas, without deadening the rooms too much, and to compliment bass trapping. Here is the design for my mix room, side wall slat resonators, that will be sealed on top and air tight in the back. I have come up with these dimensions from using the Excel spreadsheet and calculating the problem frequency points to compliment my REW measurements.

First, Is this the correct helmholz slat resonator design concept for achieving multiple frequency point tuning by alternating slat size and spacing?

I used this spacing and slat layout in the diagram from left to right:

9/32" gap, 4 1/4" slat (for 254 hz); 25/32" gap, 2" slat ( for 540hz);...and so on in this order:
254, 540, 405, 159, 540, 689, 339, 405, 159, 540, 689, 339, 405 159, 540, 689, 96

Yellow is 703 rigid insulation.

Thanks for the feedback.

[gullfo]

The slats, when spaced like that, will be more broadband in nature, which is a good thing. If you find once constructed, the room has problem frequencies, you can build panel and slat traps to correct them.

[sonicsix]

Thanks for the reply. I just wanted to make sure that alternating slat and gap width to tackle multiple frequency issues was being implemented correctly.

[gullfo]

You need to estimate the range by calculating the slot space as a percentage of the overall surface area but it will only be indicative of the range.

[sonicsix]

Do you have a link to the formula that calculates the range?

[gullfo]

basically you need to calculate the center frequency and then assume that you will have basically +/- 1/2 octave off that as a reasonable point. so if you have a design frequency of 150hz, then assume 110hz to 190hz. changing the depth of the cavity and the positioning of the cloth (if used) behind the slats will help adjust the range and the Q. many times, the cavity is split up to allow more efficiency. for example, you might divide the cavity into 3 sections and use wide slats and narrow slots for bass absorption on the top and bottom sections, and use narrower slats and wider slots for mid and HF in the middle section.

http://www.johnlsayers.com/phpBB2/viewt ... f=3&t=1363