Sound Level Meter help?

V

vicevursa

New member
Ok, I just picked up a sound level meter from Radio Shack. I have a question on how it would best for me to use it. Would it be correct to do this: Sitt where I am facing my speakers (I don't have monitors yet - still working on that) and turn the volume up on a cd of commercially mixed music that I am pushing through my mixer that is similiar to what I want to mix until the meter hits 85dB. The setting on the meter is on weighting "A". I think that is correct, but I don't know.
When (if ever) would I use weighting "C"?

Weighting "C" is for flat response, right?.

Ok, just thinking of this post my head is already getting confused on what I am trying to ask...


Thanks,

Vice
 
The A weighted scale is the "speech-interference" scale: it emphasizes the frequencies that the human auditory channel is most sensitive to. The C-weighted scale is indeed essentially flat.

The A-weighted scale seriously deemphasizes the low frequency content of the sound you're measuring. It's down at -10dB at 200Hz, and -40dB at 30hz. It's also +2dB at 2kHz, right in the center of the speech zone, and then pretty much flat in the next decade up.

If you're trying to use the SPL meter to set rough levels for monitoring, the A scale is fine. If you're trying to somehow use it to help establish a balance between LF and HF information in your mix- it's not going to help you much, and may in fact mislead you into doing excessivley bass-heavy mixes.

You can in fact use the C scale for setting your reference levels just as easily as the A scale: in fact, it'll hide LF information much *less*, since it's flat. But realistically, an SPL meter is about as useful as a spatula or a bicycle tire pump while mixing. Glance at it every so often to make sure that fatigue hasn't set in, leading to the levels creeping up and up... but other than that, I believe that basically you should ignore it.

The A scale is really important because all the workplace noise hazard laws are written with respect to it. If you want to get really nerdy about it, when you use the A scale you officially (legally) get a "sound-level reading", and when you use the flat C scale you officially get a "sound-pressure level"...
 
My understanding is you should use "C" weighting to check your SPL levels before mixing...

85dB is considered an acceptable level but recognize it can still cause hearing damage over extended periods.

I usually set up at 85dB initially - holding the meter as close to "head position" as possible. Keep in mind your head position should be an equilateral triangle formation from the monitors. What I mean by this is...if your monitors are 3 to 4 feet apart - a good distance for nearfields - your head should be 3 to 4 feet equidistant from the monitors. This is where you should check the SPL levels from.

Sometimes I will pump up the volume for a very short duration above 85 to check the low end. Sometimes I will bring the level down to 50 or 60 to check the mix balance.

Hope this helps...

zip >>
 
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