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Can I use the integrated dB SPL on my monitor controller for reference listening lvl
Old 2 weeks ago
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Can I use the integrated dB SPL on my monitor controller for reference listening lvl

I am just discovering mastering and Bob Katz's K-20 approach. It's rocking my brain. I am trying to figure out one piece of it (baby first step): the "reference listening level" dimension. From soundonsound:
and so the 'standard' reference level has been tweaked slightly with the revised figure now being 83dB SPL (as measured on a full‑bandwidth SPL meter with C‑weighting and slow averaging from a ‑20dBFS RMS pink noise source).

I think I am smart enough to locate a WAV of pink noise at -20dBFS RMS with proper frequency roll-offs, play it out Pro Tools with no signal attentuating/faders, and verify with a master meter on the output bus set to RMS that it is indeed leaving the digital system at -20dbFS.

Now, the listening side. I have a Grace m905. It has an integrated dB SPL read-out. It can be set to C weighting. Most articles I read about reference listening levels prescribe purchasing a SPL meter. How does that compare to simply using the integrated Grace m905 SPL readout? That's what it's there for, right? I wonder, how does this dB SPL readout apply when using monitors versus headphones. The headphones go right over your ears, whereas the monitors are feets away, so the same dB SPL probably sounds louder in a headphone configuration. Would that invalidate the whole point of the reference listening level? It seems a dedicated SPL meter sits external to the system, at the listener's position, though maybe the integrated SPL meter could take some math that predicts the true dB SPL at the listener's position (which is just a 0 offset in the headset configuration).

Anyway, if I send a proper pink noise out my Avid IO at -20dBFS RMS, and into my Grace, with an integrated C weighted dB SPL readout of 83dB SPL, and then mix my sessions with K-20 metering in Pro Tools Ultimate, am I... um... "doing this"?
Old 1 week ago
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Trakworx's Avatar
The m905 has a built in microphone so yes it can serve as an SPL meter. The fact that it's not exactly at the listening position may affect it's accuracy depending on your furniture/monitoring setup.

A dedicated SPL meter gives you more options to measure different spots in your room. SPL meters are not expensive and there are SPL meter smartphone apps that actually work pretty well.

Various headphone models vary in loudness so you'll have to experiment with their perceived loudness vs your speakers.

When you shoot the room with pink noise at 83dBspl, wear earplugs!
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