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Can someone explain to me how decibels work?

post #1 of 16
Thread Starter 

I am looking for safe listening levels with my headphones so I don't have hearing loss in my later years.

 

Anyways, Ipods are supposed to have an output of 110db, but my headphones go up to 120db.

 

Websites are saying you should listen to Ipod max at 85db which is roughly 80% max volume. Now my question is since my headphones go up to 120db does that mean I should put my max volume around 70-75% instead of 80%, or will my Ipod make sure the db rate never goes past 110?

 

Any other advice on this issue would be great, thanks.

post #2 of 16
It doesn't work like that. The ipod doesn't "have an output of 110 dB". It's possible the max sound pressure level (SPL) of the ipod + ipod earbuds was 110 dB. If you look at the specs for headphones, they will normally have a spec for sensitivity. This is measured in dB SPL per milliwatt or dB SPL per Volt. For example, the Audio-Technica ATH-M50X has a spec of 99 dB/V. The dB scale is not linear, it is logarithmic. A 10 dB increase in SPL is perceived as twice as loud by the human ear. (I think that's right - I sometimes get this screwed up).

The SPL generated at your ear depends on both the sensitivity of the headphones AND the voltage level being generated by the amplifier. When you turn the volume control higher, the amp produces more voltage. If you connect headphones to the ipod that are less efficient than the stock buds, then they will sound lower in volume at the same position of the ipod's volume control. Connect more efficient headphones, and they will sound louder.

There are headphones that contain limiters on the max SPL. For example:
http://www.etymotic.com/consumer/earphones/hd5.html
http://www.etymotic.com/consumer/earphones/ek5.html
post #3 of 16

I think it would be much easier for you to estimate the loudness of the headphones by listening to them. Use an iOS or android app that measures sound pressure level, play some music from a set of speakers, measure its loudness, and set the volume so it measures 80 to 85dB. Then just put your headphones on with the same music and set the volume so they sound the same loudness. It won't be perfectly accurate, but it should give you a rough idea of how loud it is.

post #4 of 16


Edited by bikerboy94 - 3/22/15 at 9:20am
post #5 of 16
Thread Starter 

This sounds a lot more confusing than originally thought, I am currently using studio Dre Beats if that helps any. Is there any type of general rule for how loud I should be listening to these?

 

What volume levels do you guys play your Ipods at?

post #6 of 16

I think there really is no exact way to determine whats too loud, because our hearing sensitivities and perceptions are all different from person to person.  The fore-mentioned safety guidelines I think are a good start.  I have low level tinnitus ringing that sounds like a high pitch squeek.  Very similar to when you clinch your jaw really hard, or the highest frequency pitch from an old school bus brakes.  Thankfully its not constant.  For me, trigger points are caffeine and caffeine loaded sodas in particular.  If I listen to treble boosted   (or upper midrange recessed) headphones for too long and too loud that also triggers it.  My first scare came from my HD580 several years ago.  I was listening to it louder than was safe, being such a smooth and seemingly pleasant sounding headphone that most definitely does sound better the louder you turn them up.  I have no idea what decibel level, but I think I was unknowingly listening to them louder than my other cans.  Given their sonic signature practically begs of it.     It caused tinnitus for 2-3 days.  I wore foam earplugs for about a week, and let my hearing naturally recover.

 

Fortunately its not permanent, but since then I am very careful with my hearing.  I keep the volumes WAY down, the longer I listen the quieter I listen.  Whisper quiet at times, just barely louder than the central air conditioning and the fish tank across the room.  This often times is quieter than the channel imbalance point on some of my amps (cheap pots), so I have to turn the volume down digitally at the source (CD/DVD player or Macbook/iTunes).  Over the years I have found my hearing to be very flexible and it kind of corrects itself to low volume levels.  Not sure what it is in my head that does this, but once my head adjusts to lower volumes I can hear things just as clearly as at louder volumes.

 

I used to think... "Oh man I just got this GREAT amp, I NEED to turn it up!!".  I guess from years of guitar playing, and car audio... thats just what you did, and thats how you got things to sound good.  That's a very dangerous philosophical way to look at the headphone amplification stage (IMHO).  From what I have learned about my own hearing damage, I flip it around and now I see my amplification stage as one of attenuation and signal reduction... NOT one of gain and boost.

 

My .02.


Edited by kramer5150 - 3/22/15 at 9:59am
post #7 of 16
There are also other factors, such as the amount of isolation provided by the headphones vs how loud your environment is. If you are in a loud environment, and the headphones are open and do not isolate well, then you need to turn the volume up much higher than if you are in a relatively quiet environment and using headphones that isolate very well. This makes perfect sense if you think about it - let's say there is 80 dB of ambient noise. If you listen to your open headphones at 80 dB, your music will sound no louder than the ambient noise,and you will need to turn the volume up. If the ambient noise level is only 40 dB, then your 80 dB music level might sound quite loud.
post #8 of 16
Quote:
Originally Posted by headphonesquest View Post
 

This sounds a lot more confusing than originally thought, I am currently using studio Dre Beats if that helps any. Is there any type of general rule for how loud I should be listening to these?

 

Already posted above, see below:

 

Quote:
Originally Posted by bikerboy94 View Post
 

 

As already discussed by billybob_jcv, you won't know this accurately from looking at the volume setting on your iPod of whatever the headphone is hooked up to. You have to measure it at the headphone.

 

 

Quote:
Originally Posted by headphonesquest View Post

 

What volume levels do you guys play your Ipods at?

 

Again, that depends on the headphone. I can set my 5g iPod to max volume on the HD600 and not only is it not loud enough to get over ambient noise in my room until around 11pm, but the sound is a bloated, nasal mess (ie highly distorted). Another example: let's take my SGS3 driving my HD600 and ASG-1.3. At roughly the same volume (by my ears) for listening, the HD600 needs to be at around 60%, but the ASG-1.3 only needs around 30%. At 50% setting on the IEM (which only happened because I forgot to turn the volume down after using the HD600 on it), I got dB-shocked and pulled the IEMs out of my ears (when I could have just pulled its plug out of the phone).

 

Think of it this way - let's say you take a small block Chevy V8. Let's say it's not just the lower block itself, but the whole engine, so specs will be identical, including the transmission gear ratios. Acceleration and top speed will be different on a Suburban, Cadillac CTS, Camaro, and Corvette, even if it's exactly the same engine and tranny. The engine is your amplifier or music player, the car body/chassis is the headphone. Then there's ambient noise, which in terms of the car can be the incline of the road or elevation of where the test is conducted (colder air, but still less oxygen density than at sea level).


Edited by ProtegeManiac - 3/22/15 at 10:23am
post #9 of 16

As a general guideline, I turn my music up just loud enough for it to be heard along side the surrounding environment.  I do not turn it up loud enough to drown out my surroundings, or at least not for very long.  So in that light, isolation is a must in a portable environment.  I have mostly open cans for office and home.  But in a portable / commuting environment the passive isolating phones and in-ears in my profile fill that need.

 

My 5 year old Bose AE2 are starting to fall apart.  Just a week ago I ordered a new pair of SoundTrue AE2i... great phones IMHO.

post #10 of 16
Thread Starter 

Thanks for the responses guys, it's a lot of process at once, and I'm still trying to make sense of it all.

 

Do you think I should be okay setting my volume at 75% volume levels with my Ipod with Studio Dre beats though?

post #11 of 16
Quote:
Originally Posted by headphonesquest View Post
 

Thanks for the responses guys, it's a lot of process at once, and I'm still trying to make sense of it all.

 

Do you think I should be okay setting my volume at 75% volume levels with my Ipod with Studio Dre beats though?


That's not how it works. Download a SPL meter to your Ipod and check like I showed in pics. Its not dead accurate but pretty close.

Will give you some idea of loudness at volume setting.

post #12 of 16
Quote:
Originally Posted by bikerboy94 View Post


That's not how it works. Download a SPL meter to your Ipod and check like I showed in pics. Its not dead accurate but pretty close.
Will give you some idea of loudness at volume setting.

Agreed. No one is going to be able to tell you for sure what the safe volume is. Measuring is the only method. Perhaps you could measure some speakers with your phone to get a sense of how loud is loud smily_headphones1.gif
post #13 of 16
Thread Starter 

I tried that and it didn't seem accurate. It was showing the same db level at 60% volume as 100% which was 80db.

post #14 of 16
Quote:
Originally Posted by headphonesquest View Post
 

I tried that and it didn't seem accurate. It was showing the same db level at 60% volume as 100% which was 80db.

Try my suggestion to measure a set of speakers, and set your headphone volume to sound the same.

post #15 of 16

Try a few different aps some are better than others. I use two that give me pretty much same reading.

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