how to determine perceived volume - Page 1
Forum section: electronics / projects

author: brownt
author_rank: Regular Contributor
timestamp: July 01, 2018, 02:45:41 am
content: I would like to determine the perceived volume for a range of sound effects with differing filters, resonance, harmonics etc. I suppose looking at the amplitude on an oscilloscope is no good because of the ears differing response to frequency.Is there a way the perceived volume can be determined?

author: Conrad Hoffman
author_rank: Super Contributor
timestamp: July 01, 2018, 03:50:44 am
content: Sound level meter with A-weighting?This is the best site if you want to roll your own-http://www.diracdelta.co.uk/science/source/a/w/aweighting/source.htmlthough some of the other pages seem to be having problems at the moment.

author: JS
author_rank: Frequent Contributor
timestamp: July 01, 2018, 04:12:14 am
content: Quote from: Conrad Hoffman on July 01, 2018, 03:50:44 amA-weighting is good for low level reference but not very representative to high level scenarios, music is often listened at relative high levels, so B or C filters might be more situable.Also, changing the frequency response alters the perceived loudness without changing the A-weighted SPL reading. That's for a given source signal, at the same level, if you boost LF and HF and attenuate the mid range in order to get the same A-weighted SPL the listener will perceive a higher level than with the unprocessed signal. Something similar happens with level, so it's not linear or equal for all frequencies, for instance, LF signal perceived level will grow faster than MF signal as the SPL increases, so it's not linear.Then, if you are talking about noise (undesired sound), there are rules of thumb for different type of noise sources to add correction factors, IE, a train noise is more forgiving than traffic (why? hard to answer but psychoacoustic effects). Single tones or periodic signals are worse than random noise, and so on.Putting a number on perceived loudness is quite tricky, there are several software plugging for your favorite audio workstation platform to do this, each designer would probably have it's own algorithm, but depending on application you could probably live without so much precision and a measured level of a filtered signal could do. If you need more use a PC to analyze the data. It also depends if you are trying to compare subtle changes or big ones, as it's not linear with freq or amplitude, small changes you could get away with a simple approach, not so much if you try to compare the perceived level of a 100Hz signal to a 10kHz signal (not to mention the buck loads of people that just can't perceive 10kHz)JS

author: brownt
author_rank: Regular Contributor
timestamp: July 01, 2018, 07:30:15 am
content: I see. So, if i record the signal with something like Audacity, is there something in that, that could help.Frequencies are guitar based, so the fundamentals are about 80 - 1400Hz. Effects include distortion and so there are many harmonics and waveshapes.

author: Audioguru
author_rank: Super Contributor
timestamp: July 01, 2018, 02:56:25 pm
content: Speakers also have differing responses to frequency, your age also. I was 69 years old when I had a hearing test. It showed that my hearing was normal for my age, NO HIGH FREQUENCIES!I tried demo hearing aids and bought some that allow my hearing frequency response to be the same as when I was young.

author: Messtechniker
author_rank: Frequent Contributor
timestamp: July 01, 2018, 03:01:22 pm
content: How about having a look at this:https://tech.ebu.ch/docs/r/r128.pdfand the move on from there.Adobe Audition and other DAWs let you adapt loudness according to the ITU-R BS.1770-2 standard.They also offer other loudness standards by the way.