# How does one solves Tangential Modes?



## pdx (Jan 30, 2014)

Hello,

I did some measurements yesterday and pretty consistently I am seeing ~320 Hz peak.

I have a bad room (11.5' width x 11' length x 8' height). Due to that, I place my speakers about 3 ft from front wall and side wall to avoid the Axial modes. I sit about 4 ft from back wall and I am about 4 feet away from the speakers. I am experimenting with near field listening to reduce the first reflection issue. Using this setup, the overall measurement was pretty good, like +/- 5 db (1/3 octave smoothing) from ~90Hz to 13KHz. The only obvious peak of +5 db (1/3 octave smoothing) was at 320 Hz. 

I checked with one online room mode calculator and found that I have Length and Height (at 321.79 Hz) + Width and Height (at 318.64 Hz) tangential mode. I think these two modes added together equals the strength of a normal Axial mode.

Since I am not trying to threat below 300 Hz yet, I think may be using acoustic foams might work for 320 Hz issue. I have 8 pieces (2 sq ft each) of 2" SoundTrax PRO Studio Acoustic Foam from NextFoam. Unfortunately, placing at the first reflection points and behind listening position did not help. 

May I know where is the most appropriate place to place the acoustic foams to reduce Tangential Modes at ~320 Hz? Thank you very much!


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## pdx (Jan 30, 2014)

After thinking a bit about tangential mode, I think I will check by placing the panels (overlay two to make them 4" thick) about 2 feet from ceiling, in a square of 4' x 2', on the back wall to reduce one of the modes. Will report back with my results.


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## pdx (Jan 30, 2014)

In post #1, I did the measurements after I moved the speakers and seating locations. However, I did not listen to music yet. I listen to some songs yesterday and found that close field listening is not for me, even the measurements were pretty good. 

May be it was the speakers, but close field listening is lacking the sound stage I used to get. So, I will be doing more speakers and listening position changes again. Please don't expect any Tangential mode research result from me anytime soon.


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