I've been wondering what the proper LFE level is when converting SACDs to LPCM for playback in my home theater, hoping you guys have more experience with this.
If I understand correctly, Dolby, DTS and LPCM tracks get their LFE signal boosted by 10dB by the AVR while DSD should not. So when converting DSD to LPCM, it'd make sense to lower the LFE signal by 10dB to avoid a bass boost on playback after conversion and get the original level back. Then again, I've heard it's not a rule as there are SACDs authored out of spec and LFE might already be lowered for home theater playback.
Since it was mainly David Bowie's Heathen SACD that got me thinking, and it's not been released in another surround format to compare, I thought I'd check his Reality SACD and compare it with the DualDisc version I have, since it's also a Tony Visconti mix from the same time period.
As you can see below, it seems the LFE level is roughly the same for both SACD and Dolby Digital mixes (barring a very slight difference caused by a different cut-off point for the low-pass filter):
1) SACD (level matched)
2) DD
Am I right in thinking one of them is incorrect? Either the SACD LFE is missing the 10dB boost when played back on a DSD machine, or the Dolby is 10dB louder compared to the SACD when the boost is applied by the AVR.
Is there any way to gauge which is more likely? Looking at the LFE signal, it does peak around 5dB lower than the fronts but not sure how much that means.
If I understand correctly, Dolby, DTS and LPCM tracks get their LFE signal boosted by 10dB by the AVR while DSD should not. So when converting DSD to LPCM, it'd make sense to lower the LFE signal by 10dB to avoid a bass boost on playback after conversion and get the original level back. Then again, I've heard it's not a rule as there are SACDs authored out of spec and LFE might already be lowered for home theater playback.
Since it was mainly David Bowie's Heathen SACD that got me thinking, and it's not been released in another surround format to compare, I thought I'd check his Reality SACD and compare it with the DualDisc version I have, since it's also a Tony Visconti mix from the same time period.
As you can see below, it seems the LFE level is roughly the same for both SACD and Dolby Digital mixes (barring a very slight difference caused by a different cut-off point for the low-pass filter):
1) SACD (level matched)
2) DD
Am I right in thinking one of them is incorrect? Either the SACD LFE is missing the 10dB boost when played back on a DSD machine, or the Dolby is 10dB louder compared to the SACD when the boost is applied by the AVR.
Is there any way to gauge which is more likely? Looking at the LFE signal, it does peak around 5dB lower than the fronts but not sure how much that means.