01-Nov-2020, 13:35
@Confused ,
The differences in frequency between measured and predicted for your modes (eg 27.4 Hz measured vs 28 Hz) can be due to one or two things. There could be an inaccuracy with the meter or the AMcoustics software but the most probable cause is that there's some flex in your walls which means that the mode is actually going to be slightly lower than a prediction based on length because the walls bulge out under pressure, increasing the length of the room axis slightly.
As for the 54.5 Hz mode being less offensive than predicted, that also could be due to one or two things but since it's harder to absorb sound as the frequency lowers and since walls//ceilings/floors do absorb some sound, it could just come down to your walls being more effective absorbers at 54.5 Hz than they are an octave lower at 27.4 Hz.
Your software tool will give you an idea of what the frequency of your modes are, and of their severity, but room construction and materials are going to modify what's actually happening in the room to a slight degree and the only way of really knowing how the room actually behaves is to measure what it does. Feeding room dimensions into a mode calculator will not give accurate results because your room surfaces aren't perfectly rigid.
The differences in frequency between measured and predicted for your modes (eg 27.4 Hz measured vs 28 Hz) can be due to one or two things. There could be an inaccuracy with the meter or the AMcoustics software but the most probable cause is that there's some flex in your walls which means that the mode is actually going to be slightly lower than a prediction based on length because the walls bulge out under pressure, increasing the length of the room axis slightly.
As for the 54.5 Hz mode being less offensive than predicted, that also could be due to one or two things but since it's harder to absorb sound as the frequency lowers and since walls//ceilings/floors do absorb some sound, it could just come down to your walls being more effective absorbers at 54.5 Hz than they are an octave lower at 27.4 Hz.
Your software tool will give you an idea of what the frequency of your modes are, and of their severity, but room construction and materials are going to modify what's actually happening in the room to a slight degree and the only way of really knowing how the room actually behaves is to measure what it does. Feeding room dimensions into a mode calculator will not give accurate results because your room surfaces aren't perfectly rigid.
Roon Nucleus+, Devilalet Expert 140 Pro CI, Focal Sopra 2, PS Audio P12, Keces P8 LPS, Uptone Audio EtherREGEN with optical fibre link to my router, Shunyata Alpha NR and Sigma NR power cables, Shunyata Sigma ethernet cables, Shunyata Alpha V2 speaker cables, Grand Prix Audio Monaco rack, RealTRAPS acoustic treatment.
Brisbane, Qld, Australia
