Originally Posted by batpig
No, Audyssey calibrates EACH speaker to play 75dB with a -30dBfs test signal, so 75 + 30 = 105dB peak output PER SPEAKER.
Audyssey does nothing with combinations of speakers, each speaker is calibrated (level/distance) and EQ'd independently.
Reference level is defined as 105dB peak output for a full scale signal for EACH channel. The LFE channel has another 10dB of headroom so it's 115dB peak.
And, yes, if you actually are able to listen at full reference level then you could theoretically hear combined SPL well above 105dB, especially when you account for LFE. I've measured 110dB+ in my room at -10 volume with crazy action effects (e.g. alien smashing stuff in Cloverfield).
But most of that is the bass.... it would be quite unusual I imagine to hear 100% peak full scale effects from ALL speakers simultaneously.
A good read: http://www.acousticfrontiers.com/201...ference-level/
Agreed on the reference level info Nyal published.
Interesting thing is Dolby Atmos commercial cinema guide does not necessarily state speaker spl for reference (like a near field measure), rather in the 2/3 back row RLP spot the spl, as real world user experiences, makes sense.
It’s the designer job to achieve that.
I’m looking for the equivalent home theater published spec from Dolby.
Each screen loudspeaker system and associated amplifiers must have a maximum output capability of 105 dB continuous sound pressure level (SPL) at the reference listening position (RLP), a point two-thirds of the distance to the rear wall of the auditorium in the middle of the seating area. Loudspeaker capability must be determined as described in Section 6. If the system specifications are not known or not provided by the manufacturer, use the following guidelines for SPL at the RLP to assess each component:
• Two-way/biamplifier: 105 dB for the low-frequency section, 101 dB for the middle-frequency and high-frequency sections
• Three-way/triamplifier: 105 dB, 101 dB, 98 dB for the low-frequency, middle-frequency, and high-frequency sec- tions, respectively
• Four-way/quad amplifier: 105 dB, 101 dB, 98 dB, 92 dB for the low-frequency, middle-frequency, high-frequency, and ultra high-frequency sections, respectively
When determining the SPL capability of a screen loudspeaker system or the low-frequency component, use half-space sensi- tivity if the loudspeaker is mounted in a baffle wall. We recommend an amplifier with 3 dB of headroom (that is, twice the required continuous power) to drive each element.”
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