Folks,
Many people believe that narrow peaks and nulls are not audible, especially nulls. While a narrow bandwidth affects a smaller range of frequencies and thus less overall energy than a wide bandwidth, very narrow bandwidths can still be highly audible. What really matters is if the frequencies being boosted or cut align with frequencies present in the source.
I think this misunderstanding arises from a 1981 paper in the AES Journal by R. Bucklein where he describes testing the audibility of boosts and cuts at various bandwidths. Some of the tests used speech and white noise, but others used music. With white noise, the total energy change affects our ability to hear the EQ. So a wide bandwidth boost increases more total energy and is more audible than a narrow boost. Likewise for wide cuts that reduce more total energy.
But for the music tests, the frequencies boosted and cut did not align with the frequencies in the music played. Music consists mostly of single tones (and harmonics which are also single tones), so the correlation between the frequencies changed with EQ and the frequencies present in the music is very important!
To illustrate the potential audibility of very narrow boosts and cuts I created a series of three short Wave files, each about 1 MB in size. The first is a clip from one of my pop tunes as I mixed it. The second is the same clip with 10 dB of very narrow EQ boost (Q = 24) at 165 Hz. The third is the same clip but with a 10 dB very narrow cut (Q = 24) at 165 Hz. I chose 165 Hz because that's an E note, which is the key of the tune. So in these examples, the boost and cut are very obvious because they align with notes the bass plays.
Original Clip
Clip with 10 dB boost
Clip with 10 dB cut
This is also related to trying to use EQ to improve room acoustics at low frequencies. One of the big problems with EQ to improve acoustic problems is it's not possible to counter deep nulls. Nulls of 20 to 30 dB or even more are very common, and you'll blow up your speakers trying to raise deep nulls enough to be flat. I've seen EQ proponents claim that nulls are not a problem because they're so narrow, and they often site the same Bucklein article!
Hopefully my example files show that even very narrow nulls can be damaging if they align with notes in the music.
--Ethan
Folks,
Many people believe that narrow peaks and nulls are not audible, especially nulls. While a narrow bandwidth affects a smaller range of frequencies and thus less overall energy than a wide bandwidth, very narrow bandwidths can still be highly audible. What really matters is if the frequencies being boosted or cut align with frequencies present in the source.
I think this misunderstanding arises from a 1981 paper in the AES Journal by R. Bucklein where he describes testing the audibility of boosts and cuts at various bandwidths. Some of the tests used speech and white noise, but others used music. With white noise, the total energy change affects our ability to hear the EQ. So a wide bandwidth boost increases more total energy and is more audible than a narrow boost. Likewise for wide cuts that reduce more total energy.
But for the music tests, the frequencies boosted and cut did not align with the frequencies in the music played. Music consists mostly of single tones (and harmonics which are also single tones), so the correlation between the frequencies changed with EQ and the frequencies present in the music is very important!
To illustrate the potential audibility of very narrow boosts and cuts I created a series of three short Wave files, each about 1 MB in size. The first is a clip from one of my pop tunes as I mixed it. The second is the same clip with 10 dB of very narrow EQ boost (Q = 24) at 165 Hz. The third is the same clip but with a 10 dB very narrow cut (Q = 24) at 165 Hz. I chose 165 Hz because that's an E note, which is the key of the tune. So in these examples, the boost and cut are very obvious because they align with notes the bass plays.
Original Clip
Clip with 10 dB boost
Clip with 10 dB cut
This is also related to trying to use EQ to improve room acoustics at low frequencies. One of the big problems with EQ to improve acoustic problems is it's not possible to counter deep nulls. Nulls of 20 to 30 dB or even more are very common, and you'll blow up your speakers trying to raise deep nulls enough to be flat. I've seen EQ proponents claim that nulls are not a problem because they're so narrow, and they often site the same Bucklein article!
Hopefully my example files show that even very narrow nulls can be damaging if they align with notes in the music.
--Ethan