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Damaging Volume Meter
MUFF WIGGLER Forum Index -> General Gear  
Author Damaging Volume Meter
matthewjuran
Sorry if this has been discussed but I wasn’t able to find an existing topic with search.

Do you know how accurate volume meter apps tend to be on smartphones? Is there dedicated gear out there to measure volume for performers?

I’ve had an app tell me 120dB was reached at a show but I don’t know if it’s accurate or not. It depends on the specific phone microphone design I assume, I don’t know the ranges of accuracy/consistency. And I'm not convinced the rules I know about what's damaging or painful is the best knowledge out there. Do you know any scientific works published about hearing damage from electric speakers?

I ask because I put my MS-20 through a 30W guitar amp+speaker which could have easily gone over a reasonable volume and maybe damaged my hearing which I really don't want to do. A display next to me that lights up when ear damaging volume is approaching or happened would be really helpful.

I’ve thought about this as an electronics product which I’d maybe start with a DIY prototype for my own use. If there was a badge people in an audience could wear that lights up when volume is too high then that would be good for the performer or audio person at the venue to see. But if the smartphone apps are good enough now then that’s good to know. Thanks.
Dave Peck
I don't know about smartphone app meters, but there are plenty of standalone hardware devices that do this. Google "SPL meters". They range in cost from about $40 to over a thousand.

Regardless of what type of meter you use, it's important to learn how to accurately do the measuring - where the meter needs to be in relation to the sound source, proper settings on the device etc.

Also, hearing damage is not based simply on the volume of the signal, it also depends on the CONTENT of the signal. For example, a low frequency random noise signal, like distant thunder, could probably be at a very high measurement level without causing any hearing damage. But a 2 KHz square wave tone could cause permanent damage in a short amount of time if it were at even a small fraction of the same level.

If it is hurting your ears, causing ringing in your ears, or having any noticeable effect on your hearing once the signal has stopped, it is probably way too loud regardless what any meter is telling you.
Blairio
Basically I wouldn't trust something as valuable (and irreplaceable) as my hearing to anything running on a smart phone. Smart phones are devices of convenience and nothing more. They cannot and should not take the place of a calibrated SPL meter.

+1 on Dave Peck's point re. content. Human hearing sensitivity is not linear. It is optimised around certain frequencies and is especially sensitive to wear, tear and fatigue around those frequencies.

Happy New Year one and all!

B
dubonaire
Interestingly, I checked a couple of iOS sound meter apps against a professional sound level meter and they were close enough to be useful. And I know how to use a sound meter. Part of my job is to visit sites to check on environmental performance and we use our phones to get a rough idea of noise impacts.

The reason they are approximately accurate is because SPL is logarithmic.

In fact you can easily check app performance to a resolution that is useful. In a quiet room you should get below 45 and probably 40. If you talk at conversation level the meter should be around 60-65. A passing truck maybe 80-85.

As for sound in large venues, the only way to go is for the audience to wear ear plugs. Even with arrays there is still going to be sound that could be too loud.

Also, really it's quite simple. If you are shouting to be heard in conversation the sound will be at a level considered dangerous.
matthewjuran
Blairio wrote:
Basically I wouldn't trust something as valuable (and irreplaceable) as my hearing to anything running on a smart phone. Smart phones are devices of convenience and nothing more. They cannot and should not take the place of a calibrated SPL meter.

The first Android app I found without ads seems to claim that measurements aren’t accurate over 100 dB and that calibration is necessary for accurate measurement below that.

Dave Peck wrote:
Regardless of what type of meter you use, it's important to learn how to accurately do the measuring - where the meter needs to be in relation to the sound source, proper settings on the device etc.

For a loud speaker configuration it seems like there would need to be a limiter in the signal chain before the amp which is calibrated with the amp for the space it’s being used in. With the guitar amp and MS-20 even a volume of 3 out of 10 was a hot input and I know it can be tempting to increase the volume as my ears adjust, but a limiter out of reach would make sure the tendency can’t hurt other people. Calibrating to the space isn’t reasonable for every possible show though.

Thanks for the SPL meter suggestion, it looks like there’s industrial standards for these devices and they are widely used.

Dave Peck wrote:
Also, hearing damage is not based simply on the volume of the signal, it also depends on the CONTENT of the signal. For example, a low frequency random noise signal, like distant thunder, could probably be at a very high measurement level without causing any hearing damage. But a 2 KHz square wave tone could cause permanent damage in a short amount of time if it were at even a small fraction of the same level.

If it is hurting your ears, causing ringing in your ears, or having any noticeable effect on your hearing once the signal has stopped, it is probably way too loud regardless what any meter is telling you.

My understanding is that the Decibel unit helps with this by being logarithmic (or that might not have anything to do with it, I don't understand dB vs SPL vs whatever well), and that 100-110 dB is a range to aim for below the threshold of pain (120 dB) but with the excitement of loud sound. Yesterday I didn’t get ringing but it has happened as an audience member of concerts before (I wear earplugs now).

dubonaire wrote:
As for sound in large venues, the only way to go is for the audience to wear ear plugs. Even with arrays there is still going to be sound that could be too loud.

This seems like the same as decreasing the volume by 20 dB. I feel like there’s a way to get the excitement of maximum safe volume using these measurement devices.

Thanks for these responses.
dubonaire
matthewjuran wrote:
Blairio wrote:
Basically I wouldn't trust something as valuable (and irreplaceable) as my hearing to anything running on a smart phone. Smart phones are devices of convenience and nothing more. They cannot and should not take the place of a calibrated SPL meter.

The first Android app I found without ads seems to claim that measurements aren’t accurate over 100 dB and that calibration is necessary for accurate measurement below that.

Dave Peck wrote:
Regardless of what type of meter you use, it's important to learn how to accurately do the measuring - where the meter needs to be in relation to the sound source, proper settings on the device etc.

For a loud speaker configuration it seems like there would need to be a limiter in the signal chain before the amp which is calibrated with the amp for the space it’s being used in. With the guitar amp and MS-20 even a volume of 3 out of 10 was a hot input and I know it can be tempting to increase the volume as my ears adjust, but a limiter out of reach would make sure the tendency can’t hurt other people. Calibrating to the space isn’t reasonable for every possible show though.

Thanks for the SPL meter suggestion, it looks like there’s industrial standards for these devices and they are widely used.

Dave Peck wrote:
Also, hearing damage is not based simply on the volume of the signal, it also depends on the CONTENT of the signal. For example, a low frequency random noise signal, like distant thunder, could probably be at a very high measurement level without causing any hearing damage. But a 2 KHz square wave tone could cause permanent damage in a short amount of time if it were at even a small fraction of the same level.

If it is hurting your ears, causing ringing in your ears, or having any noticeable effect on your hearing once the signal has stopped, it is probably way too loud regardless what any meter is telling you.

My understanding is that the Decibel unit helps with this by being logarithmic (or that might not have anything to do with it, I don't understand dB vs SPL vs whatever well), and that 100-110 dB is a range to aim for below the threshold of pain (120 dB) but with the excitement of loud sound. Yesterday I didn’t get ringing but it has happened as an audience member of concerts before (I wear earplugs now).

dubonaire wrote:
As for sound in large venues, the only way to go is for the audience to wear ear plugs. Even with arrays there is still going to be sound that could be too loud.

This seems like the same as decreasing the volume by 20 dB. I feel like there’s a way to get the excitement of maximum safe volume using these measurement devices.

Thanks for these responses.


No, 100-110db is too loud and can cause hearing damage. 85db would need to be your ceiling if you wanted to ensure hearing protection. Many audiences will be left disappointed if the average SPL across the venue is 85db. This is one reason why many people including me have hearing loss.

And what I was saying is that venue sound is not equal throughout the venue. You only have to walk around a venue to experience that for yourself. Some artists want it to be loud, and it is only with very sophisticated sound systems which include directional arrays and multiple speaker systems that you can get even close to uniform loudness across venues. And unfortunately the worse the sound system the louder it is often pushed. If you've seen those tall curved elevated speaker stacks, they are directional arrays which aim different volume levels at different parts of the venue. With the lower ones pointing closer to the stage and lower volume than the top most ones which point towards the rear of the venue being loudest.

It may surprise you to learn there are sound engineers whose profession it is to build, install and operate sound systems in venues and they use SPL meters. There are also noise limiters which can interrupt the PA if SPL is too high, these are often installed when there are environmental controls placed on the venue an the venue owner wants to make sure the local heavy metal band doesn't make them lose their licence.

A simple measurement won't give you an accurate picture. To measure SPL in a venue you need to take both fast and slow measurements across a range of locations. Some venues even have fixed metering and dataloggers.

There is a whole industry already doing what you are proposing.
matthewjuran
Thanks. I hope to play in places without professionals involved besides the band and any team with us (like at a campsite) so DIY is important. Causing hearing damage is unacceptable to me, for myself and the band and for any audience. But I like loud.

Are there recommended SPL meter brands from your experiences or recommended by those in the industry? Are there published procedures for determining safety available out there, or good books to add more background understanding?

My statement yesterday about SPL and frequency was confused, my understanding now is that SPL isn’t a good enough measure to broadly cover all types of sound because a measurement of one frequency may have a different value where hearing damage starts than another.

Perhaps there’s another measurement value for hearing damage that could be developed into a device? Like just a light for “this is damaging” vs “this is not damaging” instead of displaying a number, where the device inspects the input by frequency instead of by only overall movement of the mic.
dubonaire
matthewjuran wrote:
Thanks. I hope to play in places without professionals involved besides the band and any team with us (like at a campsite) so DIY is important. Causing hearing damage is unacceptable to me, for myself and the band and for any audience. But I like loud.

Are there recommended SPL meter brands from your experiences or recommended by those in the industry? Are there published procedures for determining safety available out there, or good books to add more background understanding?

My statement yesterday about SPL and frequency was confused, my understanding now is that SPL isn’t a good enough measure to broadly cover all types of sound because a measurement of one frequency may have a different value where hearing damage starts than another.

Perhaps there’s another measurement value for hearing damage that could be developed into a device? Like just a light for “this is damaging” vs “this is not damaging” instead of displaying a number, where the device inspects the input by frequency instead of by only overall movement of the mic.


SPL meters are already set up for hearing. That's the whole point of them. Humans are most sensitive to sound in the 2-4k Hz range, and hearing damage tends to occur in the higher frequencies because the low frequency sensors are further back in the cochlea. There are different weightings used for different purposes, but the most commonly used now is the A weighting which best reflects impacts on hearing. The A weighting is designed to allow for the Fletcher-Munson curve. https://en.wikipedia.org/wiki/A-weighting. That is why you will see noise levels often written as dBA.

For music, the technique is to take both fast and slow settings. Fast catches the transients and slow gives you more of an average. There is a bit of technique involved in measuring and interpreting the results but honestly it's not clear to me what you are trying to achieve. As I said earlier, if you just want to get in a ballpark range the phone meters are fine.

Basically you will have macro concerns that I don't think precise measurement will help you with. You will be constrained by the listener area and the sound system. Get the best sound system you can afford, the better the sound system, the better on everyone's hearing and the best listening experience. If you are going to just have speaker stacks by the stage out in the open, then you will unavoidably have a situation where it is loudest closest to the speakers, so it's almost impossible to avoid high SPL near the speakers. If you make it 85db at the speakers it's going to be way too quiet.

Although very loud sound can cause acute hearing impacts, hearing loss tends to be cumulative. It's being exposed to loud sounds for many years that is the biggest risk. Occupational exposure type levels are set at 85 dbA for 8 hours. For 2 hours 101 dBA is the equivalent. You are going to have people exposed to a range of different SPL for different time periods so how are you going to set a target SPL range across time and space?. Basically people like it loud, and honestly in the industry everyone just wears earplugs, there are earplugs available which attenuate but don't block the sound out.
umma gumma
thx for explaining all that; I'm not involved in this thread but it has been educational to read the commentary
dubonaire
umma gumma wrote:
thx for explaining all that; I'm not involved in this thread but it has been educational to read the commentary


thumbs up

Roger Waters was probably experiencing about 110 dB from that gong. I went to see Live at Pompeii when it was released actually and they put extra speakers in the cinema. It was really loud. Probably not as loud as Imax cinemas though which tend to run around 90 to >100 dBA peak. When I saw Dunkirk at Imax I'm sure it was hitting well above 100 dBA a lot. But it was so immersive!
umma gumma
dubonaire wrote:


Roger Waters was probably experiencing about 110 dB from that gong. I went to see Live at Pompeii when it was released actually and they put extra speakers in the cinema. It was really loud. Probably not as loud as Imax cinemas though which tend to run around 90 to >100 dBA peak. When I saw Dunkirk at Imax I'm sure it was hitting well above 100 dBA a lot. But it was so immersive!


wow that is cool!

it'd be nice if they did another theatrical release, would be good to see. I think it's my fave live recording; some great footage of them jamming out. what an arena/amphitheatre to play in

I really dig all the conceptual stuff those guys did
dubonaire
umma gumma wrote:
dubonaire wrote:


Roger Waters was probably experiencing about 110 dB from that gong. I went to see Live at Pompeii when it was released actually and they put extra speakers in the cinema. It was really loud. Probably not as loud as Imax cinemas though which tend to run around 90 to >100 dBA peak. When I saw Dunkirk at Imax I'm sure it was hitting well above 100 dBA a lot. But it was so immersive!


wow that is cool!

it'd be nice if they did another theatrical release, would be good to see. I think it's my fave live recording; some great footage of them jamming out. what an arena/amphitheatre to play in

I really dig all the conceptual stuff those guys did


You should read "Inside Out: A Personal History of Pink Floyd" by Nick Mason. Very entertaining read.
umma gumma
yep, done!

another really good one is Nick Sedgwick's book "in the pink"

published posthumously, documents the band during the dark side tour

http://www.pinkfloydz.com/pink-not-hunting-memoir-nick-sedgwick-afg-co rrespondent-natalie-lyons-review/

their creative process is fascinating to me. in fact, the footage of them in Abbey Road working with the VCS3 ( in the Pompeii film ) is what originally piqued my interest in synthesizers

-->allright back on topic, sorry for the diversion!
cornutt
It helps a lot if the PA. is clean. Distortion adds more high frequency content. I remember going to see Rush in their early days. Their approach to PA back then was to turn everything up to 10 (or until the venue complained). Plus they had their on-stage amps all cranked. What came out at the audience was, in the words of one reviewer I recall, undifferentiated noise. They the hired Jon Erickson to do their live sound (starting with the Moving Pictures tour, IIRC). He cleaned up the PA. He actually insisted on adding more amplification to the PA, so that it could be run with more overhead margin, hence less distortion. He also insisted that the band get their on-stage amps under control, and let the PA do the work. It was still loud, but much cleaner and easier to listen to.
dubonaire
cornutt wrote:
It helps a lot if the PA. is clean. Distortion adds more high frequency content. I remember going to see Rush in their early days. Their approach to PA back then was to turn everything up to 10 (or until the venue complained). Plus they had their on-stage amps all cranked. What came out at the audience was, in the words of one reviewer I recall, undifferentiated noise. They the hired Jon Erickson to do their live sound (starting with the Moving Pictures tour, IIRC). He cleaned up the PA. He actually insisted on adding more amplification to the PA, so that it could be run with more overhead margin, hence less distortion. He also insisted that the band get their on-stage amps under control, and let the PA do the work. It was still loud, but much cleaner and easier to listen to.


Yep definitely. A good sound system and an experienced sound engineer are key to all of this.
Blairio
cornutt wrote:
It helps a lot if the PA. is clean. Distortion adds more high frequency content. I remember going to see Rush in their early days. Their approach to PA back then was to turn everything up to 10 (or until the venue complained). Plus they had their on-stage amps all cranked. What came out at the audience was, in the words of one reviewer I recall, undifferentiated noise. They the hired Jon Erickson to do their live sound (starting with the Moving Pictures tour, IIRC). He cleaned up the PA. He actually insisted on adding more amplification to the PA, so that it could be run with more overhead margin, hence less distortion. He also insisted that the band get their on-stage amps under control, and let the PA do the work. It was still loud, but much cleaner and easier to listen to.


This is sound re-enforcement 101: the front of house guy can't do much to balance a live mix if what's coming off stage is too loud. - except make certain things even louder. The challenge is that you need a reasonable volume on stage to create atmosphere, otherwise you might as well all be playing in isolation booths.
Sir Ruff
For what it's worth, I use Decibel X on my iphone 5. I have also used the free NIOSH app, which has been tested against standalone SPL meters and found to be quite accurate (+/- 1 or 2dB). They are comparable in terms of readings, though I have found that there is a difference in Max measurements (Deb.-X reading slightly higher). Deb.-X has a LOT of annoying pop-up ads though and you have to pay to get the more commonly used C-weighted measurement (it defaults to Z-weighted, which is completely flat and not how humans hear).

Even with some slight differences in accuracy, I would much rather be using any phone app then nothing at all. At the point where sound becomes damaging (i.e., 85 dB or above) you are going to get an accurate enough reading to know when to start using hearing protection/earplugs. My feeling these days is, "if in doubt, pull 'em out"!

One confusing part about these apps, however, is that you have to learn to look at both Max AND Peak readings (on Decibel-X, peak is not normally displayed). Peak is the actual loudest SPL measured, while Max is the loudest averaged over whatever period of time. Typically Peak is at least 3dB above Max, but can also be significantly louder for impulse/impact sounds where the transient may not be picked up by the average Max measurement.

The downside to focusing on Peak SPL OTOH is that just because something crashes at 95 or 100 or 110 dB (trying banging some pans at close range!), the duration of the sound is usually so short that there is unlikely to be hearing damage (unless the sounds are happening repeatedly, i.e., drums/cymbals). So you might get a little overly concerned with inconsequential blips; for that reason, I think Max is a better value to monitor during music recording/listening, where volumes are going to be more consistent. Just be aware of Peak levels, especially once you start getting close to the 120 dB/immediate hearing damage zone, i.e., in a concert or drumming situation.
IR
matthewjuran wrote:
I ask because I put my MS-20 through a 30W guitar amp+speaker which could have easily gone over a reasonable volume and maybe damaged my hearing which I really don't want to do. A display next to me that lights up when ear damaging volume is approaching or happened would be really helpful.

While a guitar amp is not more important than your hearing, I believe the MS-20 just has a line level output (not 100% sure). A line out is much louder than guitar output, and can fry your amp as well if the volume on the synth is at max.

I think some synths like Yamaha also had a lower level output to use with guitar amps.
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