Understanding Volume Levels db . - Home Theater Forum and Systems - HomeTheaterShack.com

Old 12-30-09, 07:01 AM Thread Starter
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Cheetat1

Join Date: Dec 2009
Location: Brooklyn, New York
Posts: 15
Understanding Volume Levels db .

Hi All, I am new to the home theater scene and setting up a 7.1 system. My recieve is Onkyo - TX-N1007. This is the first reciever I have owned. The volume displays in dB. It starts out in the negatives and gets louder in lower negative numbers. For example moving from -30 to -20, the volume gets louder. I don't understand it at all. I realize my listening level for music is about -25 to -23.

Why is the display in dB and why the lower negative get louder into the positive?
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Old 12-30-09, 07:34 AM
aris

Join Date: Dec 2009
Location: Cyprus
Posts: 1
Re: Understanding Volume Levels db .

The reason your receiver is marked in db rather than in a linear scale is because this corresponds much better to the way the human ear listens, i.e. logarithmically . db is a logarithmic scale. if you don t ubderstand logarithms you are at a disadvantage to appreciate what this means but you must know that roughly speaking, the human ear thinks the the loudness has doubled when the sound pressure level incrases by 10 db ! which on a linear scale corresponds to a 10 fold increase in sound power. As an example : If 10 loudspeakers are playing at the same loudness instead of one we think that the loudness has doubled . There are significant reasons why the human ear fubctions the way it does.
As for the increase of sound as the numbers increase from negative to positive this is a normal convention. If you were going from the -3rd floor (3 below the ground) to the + 5 (i.e. 5 above) you would be going up by 8 floors. Hope this has helped you.
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Old 12-30-09, 07:59 AM
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Zing

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Re: Understanding Volume Levels db .

Quote:
cheetat1 wrote: View Post

Why is the display in dB and why the lower negative get louder into the positive?
Typically speaking, a master volume setting of 0dB represents a reference level where, in a properly calibrated system, should yield 105db of output. Some manufacturers (maybe even most) supposedly design their gear to sound best at 0dB (I believe this has to do with the gain structure of the amplifier). So the volume level indicator is designed to display how far away from reference level you are, hence the negative numbers and why it gets louder as the numbers get smaller.

Think of it as trying to reach a target and the distance you are away from it. The smaller the number, the closer you are. So at a master volume setting of -30dB, you are 30dB away from reference level. At a setting of -10dB you're now only 10dB away.
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Old 12-30-09, 08:00 AM Thread Starter
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Cheetat1

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Location: Brooklyn, New York
Posts: 15
Re: Understanding Volume Levels db .

Thanks so much. What's the deal with reference level 00 and things like that?
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Old 12-30-09, 08:03 AM Thread Starter
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Cheetat1

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Location: Brooklyn, New York
Posts: 15
Re: Understanding Volume Levels db .

I'm confused, sorry just trying to understand this. If reference level is 0dB and output of 105dB. Does that mean I have to crank up the volume to +105dB to get reference level?
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Old 12-30-09, 08:16 AM
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Zing

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Re: Understanding Volume Levels db .

Quote:
cheetat1 wrote: View Post
I'm confused, sorry just trying to understand this. If reference level is 0dB and output of 105dB. Does that mean I have to crank up the volume to +105dB to get reference level?
No. 0dB on your receiver IS 105dB SPL, assuming you have a properly calibrated system.
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Old 12-30-09, 08:25 AM
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David

Join Date: Apr 2008
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Re: Understanding Volume Levels db .

In a preamp (or receiver) with db level output scale, the reading is how far away from its reference you are. 0db is the preamp's reference level. -XXdb is some volume below reference, +XXdb is some volume above.

As an aside, I have never seen a commercial preamp where those markings are accurate, nor are they usually actually giving true db levels. The output level is just for comparison, not for calibration.
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Old 12-30-09, 09:46 AM
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lsiberian

Join Date: Mar 2009
Location: Fort Worth, TX
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Re: Understanding Volume Levels db .

Quote:
dyohn wrote: View Post
In a preamp (or receiver) with db level output scale, the reading is how far away from its reference you are. 0db is the preamp's reference level. -XXdb is some volume below reference, +XXdb is some volume above.

As an aside, I have never seen a commercial preamp where those markings are accurate, nor are they usually actually giving true db levels. The output level is just for comparison, not for calibration.
Yes they alos vary depending on the input, speakers and room. For example most HD audio tracks tend be louder than their dolby digital counterparts. Loudness is perceived as better and this is why many folks might think one receiver, cd player, or format sounds better than another. In reality it's probably a function of signal strength. To get your actual volume you'd need an SPL meter.
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Old 12-30-09, 10:39 AM Thread Starter
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Cheetat1

Join Date: Dec 2009
Location: Brooklyn, New York
Posts: 15
Re: Understanding Volume Levels db .

I am getting it now. I read online that sustained levels at or above 90dB can cause hearing loss. Wow, and reference level at 105dB can cause hearing loss also right?

Also about calibration. I am getting an SPL meter & the Avia II cabibration DVD today. Should I do the Onkyo Audyessy calibration and the SPL meter calibration?
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Old 12-30-09, 10:57 AM
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Tony

Join Date: Sep 2007
Location: Edmonton, Alberta, Can
Posts: 14,817
My System
Re: Understanding Volume Levels db .

Just a correction. Reference level is not 105db, it is 75db with peaks of 115db. The test tone your receiver uses is what is called pink noise and usually is full frequency so it will also depend on the music that your listening to as to wether your actually getting "refference level" when your receiver volume control is at 0db. Room size and acoustics all play a part in what you hear and how "loud" it sounds. Reference level is dependant on how far you sit from the speakers as well. An SPL meter will tell you what you are actually getting using pink noise and if your receivers auto room setup has done the level calibration properly.

Home theater:
Onkyo 805, Yamaha YDP2006EQ, Samson Servo 600 amp
3 EV Sentry 500 monitors across the front, 4 Mission 762i's Surrounds, SVS PB13U sub, Panasonic BDT220, Harmony 1100, Nintendo WiiU
Panasonic PT-AE8000 on a 120" 2,35:1 fixed screen

Living room system:
Sherwood/Newcastle R972, Mission 765's, SVS SBS02's, A/D/S MS3u sub, Yamaha YDG2030EQ
Yamaha KX-393 Tape deck, CDC 805 CD changer, Panasonic BD60, Sony turntable PS-T20
Panasonic TC-P50ST60, HD-PVR & WDTV Live, Harmony 900

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