Spectrogram worse after applying filters

[Joffieb]

Hi All,

I measure using REW and then generate two sets of filters, one full spectrum and one for only Sub-300Hz, which I apply in a Wiim Mini Streamer.

When I measure the results, whilst the SPL flattens out, the Spectrogram gets worse. Any idea why that is and what I can do? Also, how do my graphs look?

I also had the room empty so I decided to measure it to see the effect furniture has on it. (Second set of measurements). I have a notch filter on my sub that I use to dial down the biggest room mode (42Hz) and also find that with the notch off (i.e. mode NOT tamed), the Spectrogram looks better. Any Ideas why please?

Thanks



Joffieb

 

[moedra]

I think the spectrograms look "worse" because the range is shifting based on the highest SPL in the measurement. It looks like the whole thing is being shifted up (toward the screen) as the bass peaks are attenuated with the filter. Notice how the scale on the right changes when you switch between the measurements. The amount of decay is actually the same for all of them, which you can see in the decay graph. Everything looks reasonably okay down to 130Hz, but below that you need to absorb more.

It looks like your furniture is having the biggest effect between 200Hz and 7kHz. I can see the greatest amount of decay shifting between the furnished room and empty room in that region.

 

[Joffieb]

I think the spectrograms look "worse" because the range is shifting based on the highest SPL in the measurement. It looks like the whole thing is being shifted up (toward the screen) as the bass peaks are attenuated with the filter. Notice how the scale on the right changes when you switch between the measurements. The amount of decay is actually the same for all of them, which you can see in the decay graph. Everything looks reasonably okay down to 130Hz, but below that you need to absorb more.

It looks like your furniture is having the biggest effect between 200Hz and 7kHz. I can see the greatest amount of decay shifting between the furnished room and empty room in that region.

Thank you for taking the time to reply and for the invaluable info.