[Dark_wizzie]

Hi,
 
This is a link I stumbled upon:
http://www.head-fi.org/t/586490/approximating-headphone-volume-output-db/45
 
It's locked though.
I have HD800s with O2. I want to know how loud my music is. I'm playing in Foobar. I have Foobar volume always at max. By default I also have Windows volume at max, and I adjust volume via the volume knob on my O2. But it's hard to gauge exactly what setting my knob is at. So I am thinking, if I have the O2 volume knob at max, Foobar volume at max, adjust via sound on Windows, that would work? With gain switch not toggled.
 
I read that HD800 has a sensitivity of: 102 dB at 1 Volt RMS at 1 kc.
 
I found a calculator here:
http://www.headphone-amplifier.com/calculator.htm
 
But I don't know how to find my "line level" in mV.
According to NWavguy's blog the O2 has max output of:  7 Volts RMS & 200+ mA peak current
 
So let's say I have O2 volume knob to max. Gain switch not toggled. Foobar volume at max. Windows volume at 4 or 5. How loud is that in db to my ears?
 
Thanks.

 

[MindsMirror]

I don't think you can use the max output specs of the amp to calculate this. 7V 200mA is probably where the amp would clip, it's not really useful unless you knew what the gain and the input voltage to the amp were.
 
Also, in that calculator the sensitivity needs to be in dB/mW and you have dB/V. You could convert it, but the calculation is actually much simpler if you already know dB/V, because if you find the signal level you can directly calculate the output using the sensitivity in dB/V.
 
If you have a multimeter that measures AC voltage you could easily measure the output of the amp while playing a 1KHz sine wave and then calculate how many dB it is below 1V.

 

[cjl]

  Hi,
 
This is a link I stumbled upon:
http://www.head-fi.org/t/586490/approximating-headphone-volume-output-db/45
 
It's locked though.
I have HD800s with O2. I want to know how loud my music is. I'm playing in Foobar. I have Foobar volume always at max. By default I also have Windows volume at max, and I adjust volume via the volume knob on my O2. But it's hard to gauge exactly what setting my knob is at. So I am thinking, if I have the O2 volume knob at max, Foobar volume at max, adjust via sound on Windows, that would work? With gain switch not toggled.
 
I read that HD800 has a sensitivity of: 102 dB at 1 Volt RMS at 1 kc.
 
I found a calculator here:
http://www.headphone-amplifier.com/calculator.htm
 
But I don't know how to find my "line level" in mV.
According to NWavguy's blog the O2 has max output of:  7 Volts RMS & 200+ mA peak current
 
So let's say I have O2 volume knob to max. Gain switch not toggled. Foobar volume at max. Windows volume at 4 or 5. How loud is that in db to my ears?
 
Thanks.

You have the O2 at max volume and the Windows volume set to 4 or 5 percent? Why? Digital volume control isn't inherently a bad thing, but you usually wouldn't want it set that low with the amp cranked way up (if nothing else because of the noise floor)...

 

[castleofargh]

 

  Hi,
 
This is a link I stumbled upon:
http://www.head-fi.org/t/586490/approximating-headphone-volume-output-db/45
 
It's locked though.
I have HD800s with O2. I want to know how loud my music is. I'm playing in Foobar. I have Foobar volume always at max. By default I also have Windows volume at max, and I adjust volume via the volume knob on my O2. But it's hard to gauge exactly what setting my knob is at. So I am thinking, if I have the O2 volume knob at max, Foobar volume at max, adjust via sound on Windows, that would work? With gain switch not toggled.
 
I read that HD800 has a sensitivity of: 102 dB at 1 Volt RMS at 1 kc.
 
I found a calculator here:
http://www.headphone-amplifier.com/calculator.htm
 
But I don't know how to find my "line level" in mV.
According to NWavguy's blog the O2 has max output of:  7 Volts RMS & 200+ mA peak current
 
So let's say I have O2 volume knob to max. Gain switch not toggled. Foobar volume at max. Windows volume at 4 or 5. How loud is that in db to my ears?
 
Thanks.

You have the O2 at max volume and the Windows volume set to 4 or 5 percent? Why? Digital volume control isn't inherently a bad thing, but you usually wouldn't want it set that low with the amp cranked way up (if nothing else because of the noise floor)...

he suggested that as a possible way to calculate the loudness of the output from the fact that nwavguy mentioned a max output for the O2.
he never said he listened to his O2 that way

 

[Dark_wizzie]

  I don't think you can use the max output specs of the amp to calculate this. 7V 200mA is probably where the amp would clip, it's not really useful unless you knew what the gain and the input voltage to the amp were.
 
Also, in that calculator the sensitivity needs to be in dB/mW and you have dB/V. You could convert it, but the calculation is actually much simpler if you already know dB/V, because if you find the signal level you can directly calculate the output using the sensitivity in dB/V.
 
If you have a multimeter that measures AC voltage you could easily measure the output of the amp while playing a 1KHz sine wave and then calculate how many dB it is below 1V.

I only have what is availible on Hifiman's, and Tyll's websites. 
http://www.innerfide.../HiFiMANHE6.pdf
 
If it matters the amp/dac is from Mayflower.
 

  You have the O2 at max volume and the Windows volume set to 4 or 5 percent? Why? Digital volume control isn't inherently a bad thing, but you usually wouldn't want it set that low with the amp cranked way up (if nothing else because of the noise floor)...

 
he suggested that as a possible way to calculate the loudness of the output from the fact that nwavguy mentioned a max output for the O2.
he never said he listened to his O2 that way

Exactly what Castleofargh said. I figured it will be easier to figure out how loud stuff is if I can have some sort of standard. 
 
If I set output out as 24bit 96khz in Control Panel, the noise floor is inaudible to me even at max volume with gain switch. (Dunno why that tweak works.)

 

[ab initio]

  You have the O2 at max volume and the Windows volume set to 4 or 5 percent? Why? Digital volume control isn't inherently a bad thing, but you usually wouldn't want it set that low with the amp cranked way up (if nothing else because of the noise floor)...

 

  I only have what is availible on Hifiman's, and Tyll's websites. 
http://www.innerfide.../HiFiMANHE6.pdf
 
 
 
If it matters the amp/dac is from Mayflower.
 
Exactly what Castleofargh said. I figured it will be easier to figure out how loud stuff is if I can have some sort of standard. 
 
If I set output out as 24bit 96khz in Control Panel, the noise floor is inaudible to me even at max volume with gain switch. (Dunno why that tweak works.)

 
 
WIndow's volume control, by default, is some arbitrary log(ish) scale from 0 to 10. A setting of 5 is (only) about -10 dB (which corresponds to about half the perceived loudness).
 
As far as loudness calculations go, you are forgetting a very important key parameter to determine the SPL at your ears: the music!
 
If you use replay gain, the RMS level of the music will be something like 14 dB below full scale. Without replay gain, RMS levels of highly compressed music can be around -1 or 2 dB, whereas highly dynamic music might have rms levels below -20 dB.
 
Finally, you need to know what your DAC's output range is. It can vary from DAC to DAC. Perhaps your DAC outputs 2V rms, perhaps it's only .9 V rms...
 
Once you know what your music output RMS level is and what your DAC's output level is, then you can figure out what the output of your O2 is, and consequently the power delivered to your headphones ( and the corresponding SPL)
 
Cheers

 

[MindsMirror]

  I only have what is availible on Hifiman's, and Tyll's websites. 
http://www.innerfide.../HiFiMANHE6.pdf
 
If it matters the amp/dac is from Mayflower.

In order to calculate the loudness using the sensitivity spec, you need to know something about the signal that is going into the headphones. I can think of no other way for you to do this using your amp than to measure it directly.
 
To get a rough idea you could compare the loudness of your headphones to speakers that you measure with a dB meter app on a smartphone, or google how loud some common objects are and compare that to your headphones.
 
Edit: If it helps at all, you can see the decibel value of the windows volume control by going to the sounds control panel -> playback device properties -> levels, right click on the number and select decibel instead of percent.

 

[cjl]

   
 
 
WIndow's volume control, by default, is some arbitrary log(ish) scale from 0 to 10. A setting of 5 is (only) about -10 dB (which corresponds to about half the perceived loudness).

In Windows 7 and 8, it's an arbitrary logish scale from 0-100, and a setting of 5 is pretty darn quiet. Which version of Windows are you referring to?

 

[ab initio]

In Windows 7 and 8, it's an arbitrary logish scale from 0-100, and a setting of 5 is pretty darn quiet. Which version of Windows are you referring to?

Windows 7

Using the keyboard shortcut on my laptop i get 10 increments. Looking at the volume icon in the tray gives a 0-100 scales as you point out. If you open up the sound card options, you can adjust a slider with either arbitrary percentages or with dB. This final option is the best way to know exactly what the volume setting is actually doing attenuation-wise.

Cheers

 

[cjl]

Windows 7

Using the keyboard shortcut on my laptop i get 10 increments. Looking at the volume icon in the tray gives a 0-100 scales as you point out. If you open up the sound card options, you can adjust a slider with either arbitrary percentages or with dB. This final option is the best way to know exactly what the volume setting is actually doing attenuation-wise.

Cheers

Ahh - the one with the keyboard shortcut is likely from your laptop's drivers, and set by the laptop manufacturer. It doesn't exist on my homebuilt desktop. I didn't know about the dB slider though - that would definitely be the best way to know what the volume setting is doing.

 

[ab initio]

  Ahh - the one with the keyboard shortcut is likely from your laptop's drivers, and set by the laptop manufacturer. It doesn't exist on my homebuilt desktop. I didn't know about the dB slider though - that would definitely be the best way to know what the volume setting is doing.

You're right, the keyboard volume adjustments are device-specific. For example, my logitech wireless keyboard uses a 1-15 scale for it's volume keyboard shortcut.
 
 
For everyone to be aware:
 
1) left click the volume control in the tray

 
2) left click the sound card button above the volume slider

 
3) Open the "levels" tab. You should see a horizontal volume slider with a text box displaying the volume setting for your system volume

4) right click the text box to change the "units" of the volume slider to decibels.

5) Now you know how much software attenuation the volume setting applies. Enjoy!

 
Cheers

 

[castleofargh]

even if all that was known, then there is the output impedance it would make little difference in DB but still if you're looking for exact numbers it's needed.
I didn't get if you use the headphone output or is you just forgot to mention a usb dac.

 

[Dark_wizzie]

Bump, because I'm back at investigating this. 

 Would using a voltmeter be the key? That would tell me how much power is passing through to the headphones, and I know the sensitivity is 102db per 1V rms. And then once I figure out the volume of a track (or even a test tone), I should be able to figure out how loud my music is?
 
The other option of course, is to buy a SPL meter, but I fear the cheap ones are inaccurate for my purpose (and I don't even know which ones are accurate or not), and I think just shoving the SPL meter's mic between the earcups is an ugly solution. However, I can take the SPL meter with me where-ever I want to measure loudness... While driving with windows down, speakers, etc.

 

[stv014]

Measuring the output voltage of the O2 while playing a tone at the preferred listening volume settings at 0 dBFS level should be a good way to find out the peak voltage. Once you know that, you can calculate the average level with or without weighting by analyzing the tracks with software.
 
Note that some multimeters have a limited frequency range for accurate AC measurements. Try measuring at a few different frequencies (e.g. at 60 Hz and 1 kHz) to see how much the level varies.