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Room mode due to room height

Razorhelm

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Jan 31, 2020
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I have a room mode at about 70hz which has peaks in volume when i measure at the floor or at the ceiling.

Where is the best place to put an absorber to control this relative to the speaker?

My gut feeling is above or below the subwoofer (my sub is on a stand about 30cm above the floor) but i wonder if there is a way to work this out? My absorber is a helmholtz resonator.

Thanks
 

abdo123

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Get a second subwoofer and place it at the ceiling, raise the crossover frequency to 100.

This way it doesn’t matter where you sit (with regards to height) the response will always be the same (and will be effectively corrected by your room correction).

70Hz is too low to be treated with porous absorption. You would need something that is at least 40 cm or 15 inch deep and you would have to cover a large surface area on both your ceiling and your floor.

You could also experiment with Helmholz resonators, but that would be much more tedious than another sub.

Another solution would to place your existing sub exactly in the center between the ceiling and floor.
 

Andysu

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i nominate you to do a video to show this as what is the use of owning a mobile phone or video camera if you don't use youtube ? what is this forum about ? audio and video . i rew simulator wouldn't even known how your room is constructed it shows where the likely peaks dips are given room size but not the shape of the room or a ceiling above where bass waves can easily pass though changing the time/freq .

why not suspend the sub raise it up get a strong friend left the sub up and walk around the room with it while it plays a rew sound generator sine-wave tone . you can look at the rta see the freq rising up and down or staying at the same level within few dB depending on sine wave freq ?

you can use a microphone and walk around the room with the mic , to see where the peaks dips or some freq staying the same , its up to you .
 
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Razorhelm

Razorhelm

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More subs sounds like a neat solution, I'll look into it it thanks!
 
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