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# Can someone help me calculate the decibels my headphones produce based on my sound chip and...

I'm running windows 7 64bits, and the volume is at 30/100

Sound chip on the motherboard:

http://www.hardwaresecrets.com/datasheets/ALC889_DataSheet_1.0.pdf

I've looked everywhere and can't find the voltage output for analog, I've found tons of different values like:

//

Full-Scale Output Voltage (Gain=0dB)
DAC 1.25 Vrms

//

Another thing:

REFOUTx Output Voltage 0.5 * AVDD (which is 5V)

//

After googling i found a driver that had this text in its description, it's a driver that can be used for this onboard sound chip:

"- Power support: Digital: 3.3V; Analog: 5.0V (Minimum AVDD is 3.6V)"

//

I don't know what value to use, looked everywhere on that datasheet and it's full of technical terms and proprietary names that make no sense

important specifications:

 Frequency Response: 10Hz-30kHz Impedance: 32ohms Sensitivity (1kHz): 103dB/mW

How can i approximate the decibels of the sound it produces?

can someone help me figure this out?

Edited by An00bis - 12/28/13 at 5:42pm

Max possible output going by specs, would be around 118 db for you.

Setting of 30/100 would give a max of about 107 or 108 db.  Depending on music, your average level might be -15 db from that.  So you have possible peaks of 108 db, and average levels of perhaps 93 db.  All theoretically and assuming specs are accurate.  Kind of loud.  Near the level where OSHA would suggest limiting exposure to 6 hours per day.  Specifically OSHA suggests 8 hour exposure limits of 90 db.  Altering that by 5 db up one should halve exposure.  Or dropping 5 db one could allow twice the exposure.  Maybe lowering volume to 17/100 would be really safe.  Maybe not listening all your waking hours would be okay where you are.

Quote:
Originally Posted by esldude

Max possible output going by specs, would be around 118 db for you.

Setting of 30/100 would give a max of about 107 or 108 db.  Depending on music, your average level might be -15 db from that.  So you have possible peaks of 108 db, and average levels of perhaps 93 db.  All theoretically and assuming specs are accurate.  Kind of loud.  Near the level where OSHA would suggest limiting exposure to 6 hours per day.  Specifically OSHA suggests 8 hour exposure limits of 90 db.  Altering that by 5 db up one should halve exposure.  Or dropping 5 db one could allow twice the exposure.  Maybe lowering volume to 17/100 would be really safe.  Maybe not listening all your waking hours would be okay where you are.

Thanks for your help! but are you sure you calculated it right? 93 decibles seems extremely loud, this has really got me worrying a lot, damn, I don't want hearing damage, maybe you picked the wrong voltage from that .pdf I posted in the first poist?

is it really that serious? on my past headphones I listened at 30-40% for many hours, they were less louder but i guess 30-40% is equal to the db of the sound my new headphones produce at 30/100

yesterday I listened almost all day to them at 30% on this PC, should I worry? at night (when I went to sleep and everything was quiet) I was hearing some kind of background noise, a faint ringing, not loud, it was more similar to the blood flowing sound you hear sometimes in your ears but it was constant, a faint ringing, it was hard to notice and not annoying. Was that normal or did i damage my ears during those years of listening to headphones at 30-40/100?

if damage occurred, will it heal?

I don't think I listened 6 hours straight, maybe a couple of hours each day, does that mean I'm safe?

did they produce more DBs? 32 ohms, 110 decibels

Edited by An00bis - 12/29/13 at 6:01am
Quote:
Originally Posted by esldude

Max possible output going by specs, would be around 118 db for you.

Setting of 30/100 would give a max of about 107 or 108 db.  Depending on music, your average level might be -15 db from that.  So you have possible peaks of 108 db, and average levels of perhaps 93 db.  All theoretically and assuming specs are accurate.  Kind of loud.  Near the level where OSHA would suggest limiting exposure to 6 hours per day.  Specifically OSHA suggests 8 hour exposure limits of 90 db.  Altering that by 5 db up one should halve exposure.  Or dropping 5 db one could allow twice the exposure.  Maybe lowering volume to 17/100 would be really safe.  Maybe not listening all your waking hours would be okay where you are.

So I did a bit of research. Got myself an app for my phone that measures dBs. Fortunately, I have a very good microphone in my phone, probably the best in the smartphone market. It measures even sounds louder than 98dBs which I heard is very good for a microphone like this. I tested it and the reardings sound accurate I guess:

typing on a keyboard 50-65dBs

background noise (computer fans running) about 30-37dBs

Talking near the phone, about 70dBs, 80dBs if I'm talking loudly

tapping the microphone, 98dBs

and so on

https://www.youtube.com/watch?v=VKzWLUQizz8 this is what i tested

did some tests, I've read that for maximum accuracy you have to make a cup with your hands around the microphone and the headphone to be sure that the sound pressure is read correctly. Did that and found out that at 30/100 volume on the loudest song I could find in my music folder, that had aggressive treble and bass, full of "beats" (whatever the audiophile term for that would be) and electrical noises and the meter read about 55-80dBs (depending on what was going on during the song), with the peak being 88dBd that lasted less than half of a second. Average I saw was about 75-85dBs. So, is that safe?

The volume was pretty loud, that song was pretty noisy too  and it got almost painful so I probably didn't listen to this kind of volume anyways, so I guess I'm safe, but I'm going to a doctor anyways, just to be sure.

So this were the CALs.

Now I'll quickly test my older Senn HD429 headphones that I used for almost 2 years, same volume same song: average=50-80 and peaks were like 85 but only 2 or 3 times in the song and for very short durations. The song sounds very loud and annoying on these headphones as well, I probably didn't keep them for long at this level. It's probably one of the loudest songs I have on my PC or so it seems.

I tested (on both headphones, very similar results) some other songs I like and have listened to more and they were about 65-75dB at 40/100 (not 30) volume, even the peaks were under 80 on these songs so I guess my hearing didn't get damaged.

I usually listen to music at 20/30% for about 3-4 hours a day on average, but not all the time, maybe a couple of days a week. At night when everything's quiet I can't stand louder music so I turn it down to 10-20%.

So what does everybody think? Am I safe?

Edited by An00bis - 12/29/13 at 1:00pm

Well, I said theoretically, and using the specs you gave.  I simply converted the max voltage out put at 32 ohms and got a milliwatt value.  Then compared that to the sensitivity rating, and got what the output should be at max level.  Songs won't stay at max all the time.   And the guess of average being -15db from max on most music is a ballpark figure.  Shouldn't be too far off, won't be exact for any given song.  I assumed 30/100 is 30%.

Now your measuring it with the phone mic sounds all okay with two possible problems.  One, is the readout on the app accurate or not?  Some apps are calibrated for many of the more popular phones.  I have a couple on my phone which do more or less match what a Radio Shack sound level meter shows.  But not all do.  I deleted those that didn't.

The second is putting an earphone up to the mic.  Doubling distance from a sound source drops level by -6db.  With something that sits on or in your ear, a tiny distance change will make a big reading change.  And I think you need better coupling than just cupping your hands around it.  Maybe some other people here have an idea for a more accurate measure.

Other than that, maybe play sound over some speakers until it is pretty loud.  Then switch between speakers and headphones adjusting headphone volume until it sounds subjectively about as loud.  That should get you in the ballpark.

You can switch level display in Vista/Win7 from x/100 to dB, at least in the playback device properties, Level tab. Right click in the field with the number. (That's rather well-hidden indeed.)

The slider response itself is somewhere between linear and logarithmic, presumably mimicking its real-life cousins on mixers. On my ALC262/Vista combo, 50 is -9.5 dB, 40 is -12.5 dB, 30 is -16.7 dB, 20 is -21.8 dB, 10 is -29.6 dB, 5 is -35.8 dB and 0 gives -46.5 dB. Typically I'm quite close to the bottom end with headphones (HD580), though with Replaygain in effect it can go up to 15-20.
Note that output in Win7 may be a fair bit quieter in some cases (for reasons unrelated to overactive speech detection), an update of sound drivers is recommended then. (I've cross-checked with an ALC269/Win7 combo in a notebook, and while x/100 levels were a bit different, dB levels turned out within 1-2 dB of the desktop machine. I'll chalk up the small difference to lower output resistance for now. Volume mapping: 50 = -10.3 dB, 40 = -13.6 dB, 30 = -17.8 dB, 20 = -23.6 dB, 10 = -33.2 dB, 5 = -42.0 dB, 0 = -65.2 dB. Looks like the newer chip offers a lower minimum volume, which is good because 1 has sometimes still been too loud on the desktop.)

PS: Speaking of Realtek, their drivers used to contain a nasty bug that set up hardware sample rate wrong and triggered not-so-great quality resampling when the output device was set up for 44100 Hz 24 bit (16 Bit worked properly). Seems version 6.0.1.6263 (R2.67 or R2.66?) from late 2011 still has the problem, while it is already fixed in last year's R2.71 (6.0.1.6873) which is what the desktop runs. The former version is what was running on said notebook until now, then I found that things sounded noticeably better when SoX-resampled to 48 kHz (WASAPI exclusive mode), with 44.1 giving a somewhat metallic sound. Would fit these RMAA results. Seems fixed after installing the current R2.73 (6.0.1.7083), no more major discernible differences.
Edited by sgrossklass - 1/11/14 at 3:36pm
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