advertisement


How loud?

Tony L said:
Which is the more conventional / useful format when discussing such things? The Faber Acoustical iPhone meter gives the choice of A, C or Flat for Weighting, LP or LEQ for Level Type, and Fast, Slow or Impulse for Response. I've tended to use Flat, LP and Fast since getting the app.
Click to expand...

The correct settings are A-weighted decibels, and slow response so that you can (visually) estimate an average value over a representative sample of your listening period. Better still is an Leq reading, which integrates everything during the measurement period (e.g., 60 sec) giving you a true average value. You can do this with the Faber app on the meter. Hold the phone vertically, otherwise the Leq option won't show.

As a guideline for repeated daily exposure to sound, try to keep your average 8-h exposure to 85 dBA. Don't worry about exposures below 75 dBA, as these add essentially nothing to your daily dose.

Noise dose is comprised of two equally important elements : the intensity and the duration. Since noise intensity doubles every 3 dB, the following are all equivalent exposures that one can use to manage daily exposures. Also, don't worry if a day goes over here and there, as it is the long-term average (from repeated daily exposures) that needs to be kept below 85 dBA.

85 dBA * 8h
88 dBA * 4 h
91 dBA * 2 h
94 dBA * 1 h
97 dBA * 30m
100 dBA * 15 m
103 dBA * 7,5 m
106 dBA * 3,8 m
109 dBA * 1,9
112 dBA * 1
115 dBA * 30 s

> 115 dBA : wear your hearing protectors !

These figures are for continuous noise, not impact (eg., hammer blows) or impulse (eg., gunshot) noise, which present greater risk to hearing. At all costs, avoid unprotected exposure to repeated impact or impulse noise. Save your hearing for music, your dopamine reward system will thank you.

Jan

Edit : Serge's post above (we posted at about the same time) mentions the flat and fast settings for measuring sound ; this is not ideal for determining average exposure to sound (music or noise). Use the A weighting (dBA) and slow. Also, it can be hard to determine an average value from a fast setting when the needle is bouncing around. The Lp setting on the the Faber app gives you the instantaneous sound level.
 
sergeauckland said:
Note that even Faber themselves say that their meter could be up to 6dB out based in the variation in sensitivity of the microphones in the 'phones, so if one wants to do any absolute measurements, rather than relative, the microphone will need calibrating. I would also suggest that the frequency response of the internal microphone isn't good enough for anything other than relative measurments without caibration. I certainly wouldn't want to set up an active electronic crossover with an uncalibrated microphone.
Click to expand...

The only times I really use it are late on to ensure I'm not playing irresponsibly loud with regards to the neighbours or if I do a real big system change e.g. swap speakers over, just so I know I'm playing at the same ballpark level. It's also useful for threads like this one. I've got an old Radioshack meter too, the type with a needle meter, and the iPhone app gives a remarkably similar level when set to the same criteria, so it's certainly in the ballpark of accuracy. I'd never use it to set a crossover or anything, I'd use weeks of listening and my ears / personal taste for that! Sorry - I'm a subjectivist! \o/

janerik said:
As a guideline for repeated daily exposure to sound, try to keep your average 8-h exposure to 85 dBA. Don't worry about exposures below 75 dBA, as these add essentially nothing to your daily dose.
Click to expand...

I listen quietly and have for many years now. I'm an ex-rock musician and certainly have some degree of hearing loss / damage as a result (though way, way less than most of my peers as I realised early and started using plugs). I am determined to lose no more. My typical listening level is 75db average in the main system and about 10db less than that in system #2, which is the one that's on most of the day - that hovers between 55 and 65db most of the time, just an Eno-like background level, but loud enough to easily follow TV dialogue.
 
Tony L said:
The only times I use it are late on to ensure I'm not playing irresponsibly loud with regards to the neighbours, plus if I do a real big system change e.g. swap speakers over, just so I know I'm playing at the same ballpark level. It's also useful for threads like this one. I've also got an old Radioshack meter, the type with a needle meter, and the iPhone app gives a remarkably similar level when set to the same criteria, so it's certainly in the ballpark of accuracy. I'd never use it to set a crossover or anything, I'd use weeks of listening and my ears / personal taste for that! Sorry - I'm a subjectivist! \o/
Click to expand...

I too have a Radio Shack analogue meter, and I checked it against a legally acceptable CEL meter and it was within 1dB for general ambient noise, both A and C weighted, so quite happy with that for everyday use.

As to setting up crossovers, weeks of listening or an hour of measurement? I'd rather do it in an hour and have the remaining weeks of happily listening to music rather than tweaking, but then I'm not a subjectivist.....

S.
 
sergeauckland said:
As to setting up crossovers, weeks of listening or an hour of measurement? I'd rather do it in an hour and have the remaining weeks of happily listening to music rather than tweaking, but then I'm not a subjectivist.....

S.
Click to expand...

... are you using Fuzzmeasure ?
 
A recent article by Rod Elliot of ESP fame on SPL measurements may be of interest...

Quick quote to get you reading:

In fact, the standard A-weighting curve is accurate at or below one SPL, assuming that the listener has 'Standard' ears. Based on the 'Equal Loudness Curve' (see below), the closest match is at or near 30dB SPL - an unrealistically low noise level by today's standards. I would suggest the A-weighting curve may have relevance somewhere around 40dB SPL (unweighted!) and below. Indeed, many years ago that's exactly when A-weighting was used ... only for low level (below 40dB SPL) noise.
Click to expand...
 
sergeauckland said:
I too have a Radio Shack analogue meter, and I checked it against a legally acceptable CEL meter and it was within 1dB for general ambient noise, both A and C weighted, so quite happy with that for everyday use.
Click to expand...

I prefer the iPhone as the peak readings are the most interesting thing, and they just can't be seen on the Radio Shack, e.g. a good record or CD that shows an average level of say 75db on both meters can often be indicating peaks of well over 90db on the Faber app.

sergeauckland said:
As to setting up crossovers, weeks of listening or an hour of measurement? I'd rather do it in an hour and have the remaining weeks of happily listening to music rather than tweaking, but then I'm not a subjectivist.....
Click to expand...

Ah, but I want to actually like how it sounds, not just read some graph telling me I should! Two very different things in my world!
 
Further problems occur when measuring spl. We need to measure what we hear and we can't. the only way round this is to standardise the measurement process so measurements can be reliably repeated. For instance, was your microphone pointing up, down or straight at the source. The temptation is to point the microphone at the source. This is probably wrong as we want to measure a sound field. This field is usually measured with the microphone pointing upwards because then most of the sound field directionality is irrelevant. most microphones don't include a head or measure in stereo. And the considerations go on and on and on.
 
mudlark said:
Further problems occur when measuring spl. We need to measure what we hear and we can't. the only way round this is to standardise the measurement process so measurements can be reliably repeated. For instance, was your microphone pointing up, down or straight at the source.
Click to expand...

I've always used the meter when sitting in the listening seat with it aimed between the (substantially toed-in) speakers. My speakers are horns (Tannoys & Klipsch) so pretty directional, I'd have thought pointing the mic up would dramatically cut down upper-mid and treble energy being measured. Thankfully the Faber app rotates, so unlike most phone users the mic isn't pointing at the user's belly / wooly jumper in use!
 
Grenadier_45 said:
A recent article by Rod Elliot of ESP fame on SPL measurements may be of interest...

Quick quote to get you reading:
Click to expand...

Quite so, because Noise-Weighting intinsically is designed to simulate how annoying the noise is, so is weighted roughly to correspond with the sensitivity of our ears. As noise is supposed to be low, the standard weighting correspondance should be for quiet sounds.

S.
 
mudlark said:
Further problems occur when measuring spl. We need to measure what we hear and we can't. the only way round this is to standardise the measurement process so measurements can be reliably repeated. For instance, was your microphone pointing up, down or straight at the source. The temptation is to point the microphone at the source. This is probably wrong as we want to measure a sound field. This field is usually measured with the microphone pointing upwards because then most of the sound field directionality is irrelevant. most microphones don't include a head or measure in stereo. And the considerations go on and on and on.
Click to expand...

Indeed, microphone direction matters at HF where even nominally omni-directional microphones become increasingly directional. Furthermore, the reflections from the person holding the meter, or even the meter itself are significant at HF. With a standard SPL meter pointing at a loudspeaker, play some 10kHz tone or filtered white noise and move around behind the meter and see how the readings change by several dBs. That's why SPL meters are the wrong tool to use for making frequency response measurements, and are suitable only for overall noise measurements where the frequency distribution is more towards LF, like normal traffic noise, factory noise, office noise where there's far more energy in the LF than HF.

S.
 
what about subsonics?.........do meters register these frequencies i wonder...

i make sure the neighbours are out when i put on the vinyl copy of "Deep Purple In Rock" and wind it up a wee bit...........i know it 's LOUD when my cats start packing :)
 
denni55 said:
what about subsonics?.........do meters register these frequencies i wonder...

i make sure the neighbours are out when i put on the vinyl copy of "Deep Purple In Rock" and wind it up a wee bit...........i know it 's LOUD when my cats start packing :)
Click to expand...

The microphones used generally are pressure microphones (omnidirectional) so will go very low, but the electronics is generally rolled-off at VLF as one doesn't want things like wind pressure or VLF rumble to affect readings. Especially so, as most measurements of loudness are taken weighted, which rolls off all low frequencies and substantially reduces the HF, approximately in line with our hearing sensitivity.

S.
 
Usually between 70-85dBA here, 105+ when Ian Walker and Marco called round a few weeks ago though and it never got loud.
 
Tony L said:
Yeahbut, they have huge brains, so they'll just know. I bet whales are subjectivists...
Click to expand...

Ah but, size isn't everything, they may have large brains but they can't do a Sudoku. At least, there's no documentary evidence that whales, or any other cetacean can do such puzzles.

S.
 
You must log in or register to reply here.


advertisement


Back
Top