Sound level meter: dB-A versus dB-C

[daveneumann]

Which setting do you use to measure the sound level of your music? I was using dB-C until I started reading about the differences and realized that it was probably more appropriate to be using dB-A. Measurements tend to be lower, about 10 dB, using dB-A. I use a Radio Shack analog meter as well as an app on my iPhone, and they seem to measure pretty closely.

What is the most appropriate setting to evaluate overall sound levels? I'm interested in protecting my hearing and measuring "apples to apples" when others talk about sound levels.

Thanks,

Dave

[Masterlu]

I use the very advanced Donna-Yell-O-Meter. It’s automatic; when I hear “Turn that thing Down” I know my hearing is being protected.

Seriously, I use the dB-A weighting.

[PHC1]

Considering the human ear is highly non-linear, the typical filter used for measuring exposure levels is the A weighted filter. It is roughly the inverse of equal-loudness curve.

OSHA and others would use an A-weighted filter to measure the noise levels and have guidance in place as to how long an exposure to particular noise levels should be in a work environment.

The C weighted filter is used for measuring peak SPLs in entertainment and other industries.

[daveneumann]

Originally Posted by Masterlu

I use the very advanced Donna-Yell-O-Meter. It’s automatic; when I hear “Turn that thing Down” I know my hearing is being protected.

Seriously, I use the dB-A weighting.

Yeah, I've got a similar hearing loss warning system when my wife stomps on the floor to tell me she can't hear the TV!

[daveneumann]

Originally Posted by PHC1

Considering the human ear is highly non-linear, the typical filter used for measuring exposure levels is the A weighted filter. It is roughly the inverse of equal-loudness curve.

OSHA and others would use an A-weighted filter to measure the noise levels and have guidance in place as to how long an exposure to particular noise levels should be in a work environment.

The C weighted filter is used for measuring peak SPLs in entertainment and other industries.

Thanks Serge! From two pros whose opinions I fully trust, you and Ivan, sounds like dB-A is the way to go.

[PHC1]

Originally Posted by daveneumann

Thanks Serge! From two pros whose opinions I fully trust, you and Ivan, sounds like dB-A is the way to go.

Be kind to your ears, listen responsibly...

[W9TR]

The A weighted curve is the inverse of the 40 phon Fletcher-Munson equal loudness curves which were developed in 1933.

It cuts low frequencies a lot - 40 dB at 20 Hz.

40 phons is a very low SPL and not representative of levels we usually listen. As volume increases our hearing ‘flattens our’ and becomes more equally sensitive to tones at different frequencies.

Over time the A curve has been used to measure noise exposure as high frequencies do more hearing damage than low frequencies of similar intensity.

So if you are concerned about noise exposure use the A curve.

If you want to know how much sound power your rig is putting out, use the flatter C weighted curve.

[daveneumann]

Originally Posted by W9TR

The A weighted curve is the inverse of the 40 phon Fletcher-Munson equal loudness curves which were developed in 1933.

It cuts low frequencies a lot - 40 dB at 20 Hz.

40 phons is a very low SPL and not representative of levels we usually listen. As volume increases our hearing ‘flattens our’ and becomes more equally sensitive to tones at different frequencies.

Over time the A curve has been used to measure noise exposure as high frequencies do more hearing damage than low frequencies of similar intensity.

So if you are concerned about noise exposure use the A curve.

If you want to know how much sound power your rig is putting out, use the flatter C weighted curve.

Who knew I'd need that physics 101 class I constantly cut back in college? Thanks, this is a very helpful addition to Ivan & Serge's replies. And yes, I'm mainly concerned about protecting what's left of my old ears!