Sound level meter with headphones

[ratdog]

I was going to do a search on this but of course it's down. My ears have been hurting lately, I think it might be a cold but was concerned it might be because of my headphones. I stuck a spl meter from radioshack flush against the drivers in my headphones and got a reading of about 92 dB at my preferred listening level. According to the book I should be able to listen at these levels safely for 6 hours. Is putting a spl meter flush to the headphones going to give me an accurate reading?

Also going back and forth between the R & L drivers I noticed that the L was about 2 dB higher. Could this be normal because of different stereo mastering levels or could one driver possibly be bad?

 

[pedxing]

Some of those charts that show the maximum recommended exposure times are just guidelines. For example, the OSHA guidelines may still lead to hearing loss even if the person was exposed for periods of time smaller than the recommended maximum time period.

You may want to retrain the way you listen to your headphones to a much lower level of sound intensity.

Meausring the sound intensity flushed to the headphon is not accurate because you are taking into account of the acoustic properties of the headphones pushed against your ears or head. What your ears experience might even be louder.

 

[ratdog]

That makes sense as the pad would cup around the ear and be louder. Has anyone else tried to measure the sound level?

Quote:

Originally Posted by pedxing Some of those charts that show the maximum recommended exposure times are just guidelines. For example, the OSHA guidelines may still lead to hearing loss even if the person was exposed for periods of time smaller than the recommended maximum time period. You may want to retrain the way you listen to your headphones to a much lower level of sound intensity. Meausring the sound intensity flushed to the headphon is not accurate because you are taking into account of the acoustic properties of the headphones pushed against your ears or head. What your ears experience might even be louder.

 

[ServinginEcuador]

If you used music to get those readings it is not unusual. Music is very difficult to use to get accurate readings. The only way is to loop a small portion and read it while reading both earpieces during that entire time, taking note of the highs and when they occur.

Also, place the meter a good inch away from the ear piece to present a more accurate representation of how loud something is in your ear drum.

Also, is your SPL meter set to slow or fast? Is is A or C weighted? Do you have it set to read maxs or average? These can all make a difference.

Also, the 6 hour figure you got, is that per week, or per day?

 

[ratdog]

Quote:

Originally Posted by ServinginEcuador If you used music to get those readings it is not unusual. Music is very difficult to use to get accurate readings. The only way is to loop a small portion and read it while reading both earpieces during that entire time, taking note of the highs and when they occur. Also, place the meter a good inch away from the ear piece to present a more accurate representation of how loud something is in your ear drum. Also, is your SPL meter set to slow or fast? Is is A or C weighted? Do you have it set to read maxs or average? These can all make a difference. Also, the 6 hour figure you got, is that per week, or per day?

Slow on C. The 6 hours was per day per the radio hack pamphlet.

 

[ServinginEcuador]

ratdog,

Lower the volume a little and preserve your hearing. Are you having any ringing in your ears at all? If not, be thankful and lower the volume. If you are, lower the volume and be thankful! Having tinnitus isn't fun, so lower the volume a little and keep your hearing preserved.

 

[john_jcb]

Here is a chart that I like to use. As you can see the amount of safe time at 92 dB varies dramatically depending on who you listen to. I try and follow the EPA guidelines. For them you only have 11 minutes at 91 dB. Remember, as a rule of thumb, that as you go from 81 to 91 dB the loudness doubles. It doubles again going to 101.

 

[ServinginEcuador]

John,

Thanks for the chart info. I guess I am now more secure in my normal listening levels of around 72dB. I don't like to listen at more than abotu 78dB or so for any length of time, so I guess I need to make sure that I keep it at the lower end.

 

[john_jcb]

Doug

That is around where I listen as well. I was playing around with my new speakers and a sound meter last week and I was amazed how loud 80 dB really is. I put in Led Zeppelin and went to around 100 dB for a short time, way too loud for me. Makes me wonder what I was thinking when I saw them from the first row in Seattle.

My next test will be to measure the wind noise in a car with the windows down at various speeds.

 

[ServinginEcuador]

Quote:

Originally Posted by john_jcb My next test will be to measure the wind noise in a car with the windows down at various speeds.

John,

I felt the same way when I first got my meter. I want to know how loud the movies I watch are; how loud the bus is that I ride in; how loud my friends talk, etc.

I am concerned about my hearing, and want to ensure I have it for as long as possible. At the same time I want to try and convince others to lower the volume on their listening sessions as well. I won't become annoying, just voice my opinion and move on. Lots of young peple here with the thought that they're bulletproof and immune from what affects every other human being in the world.

 

[pedxing]

Edit: misunderstood previous quote. Eradicated my comment.

Its scary to see how OSHA vs EPA varies. They might be referring to different types of noises (continuous versus instantaneous).

I think the sound entering your ear will become louder because the human ear was designed to funnel certain sounds into the ear drum. I doubt the radio shack sound meter compensates for this problem acoustically or electronically.

I am not sure how to read the db charts correctly. My original assumption several years ago was that the db level is what the ear drums are experiencing. However, it could be the amount of sound energy emitted at the source. Does anyone know how the context of these db measurements are suppose to be applied in respect to our heapdhone listening experience?

 

[ServinginEcuador]

Quote:

Originally Posted by pedxing Sorry, my understanding of logs are rusty, but I think the difference between 81 db and 91 db is ten times. Every 3db difference is a difference of a factor of 2.

My guess is that he's referring to the fact that those 10dB will appear to be about twice as loud to your ears, not an actual account of how much the 10dB difference will be.

I don't think so. I can tell the 3dB difference using my headphones any day of the week. Since I listen to my music at about 62dB I can easily tell an increase of 3dB as nearly double the volume. A 10dB difference is HUGE to my ears, and it definitely sounds way more thantwice as loud to my ears.

 

[ratdog]

How are you guys getting readings of the dB output of your headphones? I took my spl meter to my home speaker system and my preffered listening level was 74-78 dB (anything over 85 dB was way too loud) Measuring my phones at 74 dB seemed a little too low.

Thanks for the chart John. According to my spl meter I can't get the definition I'm used to on a decent speaker sytem at 70-78 dB listening levels with my cans.

 

[john_jcb]

The charts are meant to reflect the sound at the persons position. As an example a guy working a punch press may have noise at his press of well over 100 dB but it attenuates quickly with distance. In factories they do averaging and determine if hearing protection is required based on guidelines that are provided by OSHA. Companies are erring on the conservative side as it is cheap insurance to provide foam plugs and require their use as opposed to getting one hearing loss law suit.

Actually the charts work equally well for headphones. Placing the sensor at the approximate outer ear position will get you pretty close.

Notice too that the chart is in dBA as opposed to dBC. The A weighting more closely follows the ears response to sound and the apparent loudness drops off quickly below 1000 Hz. The C weighting is pretty flat tailing off at the lowest frequencies. Here is a chart that shows the differences between the scales on your meter. This is just about the same one that is in the Radio Shack manual.

 

[ratdog]

On my spl the difference between A&C is very minimal. if you say that the sound level meter works well with headphones then that's pretty scary because What I deemed way too loud on my speaker setup didn't appear AS loud with my headphones. If I was listening at high levels 85-92 dB with my headphones should I give my ears a break? If so, How long?