23-Sep-2018, 00:15
One more thing about SAM and why you're noticing a big difference even with it set to 0%.
I read somewhere the other day, can't remember where, that phase correction in the bass can have the effect of providing up to an extra half octave of extension just on it's own and phase correction is what you're getting at the 0% setting.
Bass drivers tend to have a varying phase shift at different frequencies, just check the phase and impedance test charts in Stereophile's speaker measurements and you can see just how much the phase can vary over the bass frequencies. Now phase changes over time and ideally we would want to have peak amplitude in the phase cycle for the bass note at the time the initial transient attack of the note arrives at our ears, which also means we don't want phase shift in the bass driver but that's not something most (any?) speakers can deliver. After the initial transient attack, the level of the note starts to drop as the note dies away so we hear the note decaying into silence but the phase of the sound wave also changes over time and if we weren't getting peak amplitude with the initial transient attack, the peak amplitude in the phase cycle will occur a fraction of a second later while the note is decaying but we tend to take a lot of our cues for how loud the note is from the initial transient attack and because the amplitude of that was lower than it should have been because of the driver's phase error, the sound pressure level will be reduced and sound pressure level is what we experience as loudness. Basically this means we won't hear the note sounding quite as loud as it should sound. Correcting the phase errors for the bass driver should therefore result in louder transient attacks so we hear louder bass and because the level of the bass is higher down where the speaker normally starts to roll off, we can hear the frequencies down there a little better so we notice more bass extension, or at least that's how I think phase correction at bass frequencies can work to deliver more bass extension.
As I said, the comment I read said that phase correction can deliver up to half an octave of additional extension. Different speakers have different amounts of phase shift as the charts in Stereophile's tests show, and of course different speakers roll off at different frequencies as well so the amount of added bass extension you will notice with SAM set to 0% will vary depending on your speaker's amount of phase shift in the bass and also the point at which it starts to roll off. The phase shift at the frequency where your speakers start to roll off may be large enough for phase correction to produce a quite noticeable effect for you but you may also find that others may not notice it as much as you do. When we're very familiar with the sound of our speakers, small changes can be quite noticeable for us but less noticeable to others who don't have that familiarity.
I read somewhere the other day, can't remember where, that phase correction in the bass can have the effect of providing up to an extra half octave of extension just on it's own and phase correction is what you're getting at the 0% setting.
Bass drivers tend to have a varying phase shift at different frequencies, just check the phase and impedance test charts in Stereophile's speaker measurements and you can see just how much the phase can vary over the bass frequencies. Now phase changes over time and ideally we would want to have peak amplitude in the phase cycle for the bass note at the time the initial transient attack of the note arrives at our ears, which also means we don't want phase shift in the bass driver but that's not something most (any?) speakers can deliver. After the initial transient attack, the level of the note starts to drop as the note dies away so we hear the note decaying into silence but the phase of the sound wave also changes over time and if we weren't getting peak amplitude with the initial transient attack, the peak amplitude in the phase cycle will occur a fraction of a second later while the note is decaying but we tend to take a lot of our cues for how loud the note is from the initial transient attack and because the amplitude of that was lower than it should have been because of the driver's phase error, the sound pressure level will be reduced and sound pressure level is what we experience as loudness. Basically this means we won't hear the note sounding quite as loud as it should sound. Correcting the phase errors for the bass driver should therefore result in louder transient attacks so we hear louder bass and because the level of the bass is higher down where the speaker normally starts to roll off, we can hear the frequencies down there a little better so we notice more bass extension, or at least that's how I think phase correction at bass frequencies can work to deliver more bass extension.
As I said, the comment I read said that phase correction can deliver up to half an octave of additional extension. Different speakers have different amounts of phase shift as the charts in Stereophile's tests show, and of course different speakers roll off at different frequencies as well so the amount of added bass extension you will notice with SAM set to 0% will vary depending on your speaker's amount of phase shift in the bass and also the point at which it starts to roll off. The phase shift at the frequency where your speakers start to roll off may be large enough for phase correction to produce a quite noticeable effect for you but you may also find that others may not notice it as much as you do. When we're very familiar with the sound of our speakers, small changes can be quite noticeable for us but less noticeable to others who don't have that familiarity.
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
