[droopdog7]

I've been curious about my typical listening level and am wondering if there is a way to figure it out if I know max decibels (based on amp power) and assume the knob works on log scale. According to Ifi website, my amp-headphone combo max (I believe) is 123 db. I generally listen between 11 and 12 o' clock on the knob.

Anyway to figure it out?

 

[Radaos]

SPL meters are fairly cheap.

 

[sander99]

a way to figure it out if I know max decibels (based on amp power) and assume the knob works on log scale.

The amp-headphone max and the position of the knob is not enough information. Two volume knobs can both work on a log scale but still have different "gain and knob position" characteristics. Also the actual spl will depend on the actual input signal level. Also the max position could be such that the max input level doesn't correspond with the max spl, but leads to clipping. (It is normal to have some extra range to be able to play a softer recording at full level).

 

[sander99]

SPL meters are fairly cheap.

Also SPL meters that are suitable to use with headphones?

 

[Radaos]

See here:

 

[droopdog7]

SPL meters are fairly cheap.

I didn't know they had any that can be used with headphones? Thanks.

 

[redrol]

what I do is put on IEMs, but just one ear, then put my system on with the SPL meter where my other ear is, then just match the 2 volumes and check SPL. Pretty easy.

SPL should be measured in DB-A weighted FWIW.

 

[gregorio]

SPL should be measured in DB-A weighted FWIW.

No, it shouldn’t. “C” weighting is used for measuring/calibrating audio system SPL. This is because these different weightings were designed for different loudness contours. “A” weighting was designed for very low SPL levels, not the relatively high levels output by speakers/HPs, which falls within the “C” weighting.

Manufacturers often use the “A” weighted scale as a measurement for noise because it will give a lower/more impressive looking result than the actual noise level.

G

 

[redrol]

'A-weighted decibels, abbreviated dBA, or dBa, or dB(a), are an expression of the relative loudness of sounds in air as perceived by the human ear. '

You are incorrect sir.

 

[gregorio]

'A-weighted decibels, abbreviated dBA, or dBa, or dB(a), are an expression of the relative loudness of sounds in air as perceived by the human ear. '

Yes but ONLY at low SPLs. The A, B and C weightings were designed for the different equal loudness contours, A being for the lower level contours (40dB and lower), B for the middle and C for the higher levels. B is not used much anymore, A is used for environmental noise and also in audio for the low level noise produced by audio components. C is used for speaker/room calibration and audio entertainment in general. The A weighting is particularly inappropriate for music and most other audio entertainment because of the high bass levels, which the A weighting removes.

This is basic knowledge for sound/music engineers and it shouldn’t be difficult to discover this for yourself! However, here’s some confirmation:

“In this paper it has been verified that the A-weighting metric performs poorly for any signal outside of the mid-range of human perception. While the metric was not intended for applications outside of this area, the ease of use for A-weighting has made it the go-to metric for environmental noise measurements in government standards worldwide. Based on the information above, if one were to improve the A-weighting filter, the algorithm should be modified to adjust the amount of low frequency attenuation with respect to amplitude.” -
JASA “A-weighting the equal loudness contours” - Jeremy Charbonneau, Dr. Colin Novak, Dr. Robert Gaspar and Dr. Helen Ule, University of Windsor, 2012. Full text here.

You are incorrect sir.

Sure, along with the science, industry bodies like Dolby, NTSC, EBU and the engineers who make the sound and music you’re listening to!

 

[castleofargh]

loudness regulations are based on dBA so your advice is relevant, but Gregorio is correct when he explains the differences. Both A and C are related to human perception, with A showing a much stronger deviation on both ends of the spectrum, like the way quiet audio is perceived(cf. equal loudness contour). While C is almost flat, like how loud sounds are perceived.
edit: I'm too late ^_^

 

[redrol]

I assumed A weighting had something like a Fletcher Munchen curve applied.


'Perceived discrepancies between early and more recent determinations led the International Organization for Standardization (ISO) to revise the standard curves in ISO 226. They did this in response to recommendations in a study coordinated by the Research Institute of Electrical Communication, Tohoku University, Japan. The study produced new curves by combining the results of several studies—by researchers in Japan, Germany, Denmark, UK, and the US. (Japan was the greatest contributor with about 40% of the data.)

This has resulted in the recent acceptance of a new set of curves standardized as ISO 226:2003. The report comments on the surprisingly large differences, and the fact that the original Fletcher–Munson contours are in better agreement with recent results than the Robinson–Dadson, which appear to differ by as much as 10–15 dB especially in the low-frequency region, for reasons not explained.[6]

According to the ISO report, the Robinson–Dadson results were the odd one out, differing more from the current standard than did the Fletcher–Munson curves. The report states that it is fortunate that the 40-phon Fletcher–Munson curve on which the A-weighting standard was based turns out to have been in agreement with modern determinations.[4]''

Im certinaly not saying im right but this seems more complicated than assumed.

 

[gregorio]

I guess this gets deep down the rabbit hole of human perception.

Yes it does a bit. On the one hand we’ve got what the different weightings were actually designed for and on the other we’ve got what they’re actually used for. They should of course be the same but for various reasons they’re often not.

We shouldn’t be using the A weighting for loud industrial noise but that’s what all the laws require. The C weighting isn’t perfect for measuring room/studio SPL either, although it’s a lot closer than the A weighting but regardless, calibration levels are always given in terms of the C weighting (using the slow response meter option), so that’s what we need to use for an accurate comparison.

G

Edit: Also notice in your quote that it states widespread use “for Noise Measurement”. The OP doesn’t want to measure the noise, he wants to measure the music/sound.

 

[gregorio]

With regard to your edit.

I assumed A weighting had something like a Fletcher Munchen curve applied.

Yes, the "A" weighted curve is effectively the inverse of a (updated) Fletcher-Munson curve. However, so are the B and C weightings but they are effectively the inverse of different (higher level) Fletcher-Munson curves.

Im certinaly not saying im right but this seems more complicated than assumed.

Yes, it is complicated, in fact it's still more complicated than you assume. The "A" weighting has been revised several times and it's important because it's an ISO standard that is used by other international bodies to define hearing damage from noise exposure and by governments to set regulations on noise levels. However, it's more complicated than you assume because you're only going down one rabbit hole, the "A" weighting rabbit hole and that's the wrong rabbit hole! ... Or more accurately, how deep the A weighting rabbit hole goes is largely irrelevant because you're ignoring other more pertinent rabbit holes.

"A" weighting is about noise: The levels of self-noise produced by audio equipment, the level of the noise floor in rooms, the levels of noise exposure over time causing hearing damage, the levels of noise above which is illegal or requires employers to provide hearing protecting, etc. However, the question asked by the OP was not about noise levels, it was about music/sound levels and this distinction is important in this instance because it's a different rabbit hole! For example, @castleofargh stated "loudness regulations are based on dBA ..." - This is not strictly true, noise level regulations are based on dBA but "loudness" regulations are not. Loudness regulations are based on the LKFS (LUFS in EBU regions) measurement and utilse a different curve from those previously mentioned, the "K" weighted curve. "Loudness" is a different rabbit hole and more relevant to the OP's question than noise levels. The LKFS/LUFS measurement is an integrated digital domain weighting measurement which is equated to SPL using the formula: 78dBSPL(C) = -20dBFS @ 1.228vRMS. Note that the SPL measurement is mandated using the "C" weighting (as are all speaker/room calibration measurements). Also note that this 78dBSPL(C) figure is for speakers in quite a large room, not for HPs. This level would be lower in a smaller room and lower still for HPs.

G

 

[castleofargh]

Sorry, I meant health regulations for factories and stuff, I didn't think about audio visual regulations when I wrote that.