Thanks a lot Fons. When I pan pink noise with at W at -20dBFS RMS, the individual X and Y channels peak at about 3dB higher. Is that why you said to meter at 86dB and not 83?
It's curious this thing about the summing of channels. When I first read about k-system monitor calibration, I understood, incorrectly, that to arrive at this cinema standard of 83dB, one would have to lower the SPL meter reading of each channel to different a value depending on the number of speakers. ie. 83dB = x + 10log(number of speakers) where x = the necessary reading in the meter for each speaker to achieve an overall level of 83dB. eg. for a 5.1 system x is aprox. 76dB SPL I wrote to a forum on Bob Katz's site and he responded saying no, all should be set to 83dB SPL..."Don't worry about how it adds up. This increases the headroom for the mix engineer, who doesn't have to push each channel as hot to get the same loudness.... and therefore the enjoyment of multiple channels. It also partly explains why stereo is so crippled a medium." I guess also with cinematic sound - it's more rare to have all channels on full all at once (or maybe that's the films i watch!). For my current purposes, I'd like to reproduce as best as possible, ambiental b-format recordings over an array of speakers - and preferably try to match SPL measurements taken at each recording location. Do you think the formula above would be correct to match levels in this way? ie. if I make a recording at a site where the SPL is 70dB, during playback I meter this material (the W channel) at -13dB RMS on a k-20 meter, and in the case of a 14 channel system, calibrate each speaker channel at 71.5dB SPL (x = 83 - 10log14). Cheers, Iain Em Tue, 2014-03-18 às 17:18 +0000, Fons Adriaensen escreveu: > On Tue, Mar 18, 2014 at 05:09:21PM +0000, Fons Adriaensen wrote: > > > A stereo system calibrated as you describe will output 86 dB SPL > > if both channels are -20 dB on the K-meter. > > > > To calibrate the AMB system, send the pink noise through an > > AMB panner, set the level for -20 dB RMS in W, and pan the sound > > in a direction corresponding to a speaker. Adjust decoder/amp > > gain for 86 dB SPL. Check this remains more or less constant in > > all directions. > > Just to avoid all confusion, -20 dB RMS here means an indication > of 0 dB on the K-20 meter ! > > Ciao, > _______________________________________________ Sursound mailing list Sursound@music.vt.edu https://mail.music.vt.edu/mailman/listinfo/sursound
