How much above 0db is safe? - Page 2 - AVS Forum
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post #31 of 50 Old 06-18-2012, 11:02 AM
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Yeah the Harman has them, but if the Denon doesn't have ins (and the Harman doesn't have Lossless) seems I'm out of luck.

I'm ok with the Denon, but I'm finding myself driving it to 0db to be happy with the volume.

It goes up to +18db, but I've been keeping it at 0db, due to fear of causing any damage (I thought I had read somewhere to limit it to 0db for the Denon).

I'm thinking some tracks will be a little quieter, and I'm going to want to be pushing it to +5db/+10db (I have the Pioneer FS51 set, and they aren't overly efficient), which is why I posted to begin with, to kind of get an idea of WHAT (technically) is happening when I go above 0db.
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post #32 of 50 Old 06-19-2012, 12:54 AM
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As a lot of other people have stated general 0db should be more than enough, but if you need to turn it up more than go for it, as long as it is still comfortable to listen to you'll be fine
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post #33 of 50 Old 06-19-2012, 05:46 AM
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Just pay attention to whether you're hearing distortion when you turn up. What happens from say 0 to plus 5 is the same thing that happens from minus 5 to 0. It's just louder, so it calls for more power from the amp and pushes the speakers harder. Your receiver would likely self protect by shutting down if pushed too hard. You could damage the speakers, however, and hearing distortion, whether its the amps clipping or speaker distortion, is a sign you're running a risk. It's only a problem if it's a problem, and it is so room and gear dependent that there can be no set rule on whether you can go above 0,especially since the power requirements of different speakers vary so much. I suspect I'd be clipping my amps on big peaks and am sure my speakers would be well into compression if I listened at reference, even, but -20 is often just fine for me. Everybody's different . . . .
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post #34 of 50 Old 06-19-2012, 06:14 AM
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Originally Posted by JHAz View Post

Just pay attention to whether you're hearing distortion when you turn up. What happens from say 0 to plus 5 is the same thing that happens from minus 5 to 0. It's just louder, so it calls for more power from the amp and pushes the speakers harder. Your receiver would likely self protect by shutting down if pushed too hard. You could damage the speakers, however, and hearing distortion, whether its the amps clipping or speaker distortion, is a sign you're running a risk. It's only a problem if it's a problem, and it is so room and gear dependent that there can be no set rule on whether you can go above 0,especially since the power requirements of different speakers vary so much. I suspect I'd be clipping my amps on big peaks and am sure my speakers would be well into compression if I listened at reference, even, but -20 is often just fine for me. Everybody's different . . . .

Everyone is different, and apparently every amp is different. I was under the impression that 0db meant they emulated reference levels as closely as possible.

So for those saying 0db is "plenty for me" well, we have different amps, and different speakers. The sensitivity of speakers can make a pretty decent difference in sound volume/output.
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post #35 of 50 Old 06-19-2012, 06:14 AM
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Originally Posted by beefjerky21 View Post

As a lot of other people have stated general 0db should be more than enough, but if you need to turn it up more than go for it, as long as it is still comfortable to listen to you'll be fine

This makes no sense... a lot of people have stated that 0db means nothing... therefore 0db cannot be "enough" as it differs for each amp and 0db isn't representative of any actual value.
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post #36 of 50 Old 06-19-2012, 07:52 AM
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0db isn't representative of any actual value.

Correct, this has been mentioned many times. The dB expresses a ratio of two values. You need to define the reference first.
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post #37 of 50 Old 06-19-2012, 08:15 AM
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Originally Posted by SAM64 View Post

Quote:
0db isn't representative of any actual value.
Correct, this has been mentioned many times. The dB expresses a ratio of two values. You need to define the reference first.

Yeah, I'm guessing things like Audyssey help "match" reference levels throughout?
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post #38 of 50 Old 06-19-2012, 12:03 PM
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Originally Posted by master0068 View Post

Yeah, I'm guessing things like Audyssey help "match" reference levels throughout?

The recent versions of Audyssey (since DynVol and DynEQ came out) attempt to set the speakers so that zero on the volume dial equals "reference" level, defined (for movie mixing stages) as 85 dB SPL per speaker at the listening position (surrounds are lower but there are multiples) with an input of band limited pink noise at -20dBFS. All well-understood real repeatable facts. Most home units use test tones at -30dBFS because people found 85 dB too dang loud. So they calibrate to 75 dB SPL per speaker with the reduced test tone. Works out the same. There is no similar "reference" level for music or other media.
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post #39 of 50 Old 06-19-2012, 01:34 PM
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^^^
If after running Audyssey one of your speaker trims is set to -2dB, Audyssey believes it needs to reduce the gain to that particular speaker by 2dB in order to hit 75dB, correct?

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post #40 of 50 Old 06-19-2012, 06:06 PM
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Quote:
Originally Posted by holt7153 View Post

^^^
If after running Audyssey one of your speaker trims is set to -2dB, Audyssey believes it needs to reduce the gain to that particular speaker by 2dB in order to hit 75dB, correct?

basically yes
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post #41 of 50 Old 06-19-2012, 07:57 PM
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thanks-just wanted to be clear on how bumping trims affects 0 reference level.

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post #42 of 50 Old 06-19-2012, 11:41 PM
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I do movies at reference as my room is treated and XT32 does the rest. Audio is clear with punch when needed and bass SQ is excellent.

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post #43 of 50 Old 06-20-2012, 04:31 PM
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This whole discussion is totally meaningless, because the "0db" you are talking about is only a setting on your amplifer or receiver.

It has NO relationship to the actual SOUND PRESSURE LEVEL in the room!

"0db" on one system is different than another, because a difference in speaker sensitivity as well as the input voltage from the source charges everything.

If you are concerned about what is "SAFE" you need to get a meter that measures the actual SPL in the room, not a meaningless setting on your equipment.



Quote:
Originally Posted by retroeric View Post

I have a new 5.1 setup (Yamaha RX-V765 receiver with NHT Absolute Speakers). When I set the volume as high as 0db, I get fairly loud sound but not what I was expecting (not what I want for movie night!).


Is it safe to go much higher than 0db? What is the highest I should consider setting it?
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post #44 of 50 Old 06-20-2012, 04:35 PM
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Quote:
Originally Posted by commsysman View Post

This whole discussion is totally meaningless, because the "0db" you are talking about is only a setting on your amplifer or receiver.
It has NO relationship to the actual SOUND PRESSURE LEVEL in the room!
"0db" on one system is different than another, because a difference in speaker sensitivity as well as the input voltage from the source charges everything.
If you are concerned about what is "SAFE" you need to get a meter that measures the actual SPL in the room, not a meaningless setting on your equipment.

Well this is an inaccurate statement as well. SPL is NOT an indication of "safety" as all amplifiers are unique and do not output the same level of volume.

The OP's question is completely valid, because below 0db the receiver is attenuating the volume, and above it is doing something else, which may or may not be pushing the amp past its limits, depending on the manufacturer, and the model.
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post #45 of 50 Old 06-20-2012, 05:26 PM
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Originally Posted by master0068 View Post

Well this is an inaccurate statement as well. SPL is NOT an indication of "safety" as all amplifiers are unique and do not output the same level of volume.
The OP's question is completely valid, because below 0db the receiver is attenuating the volume, and above it is doing something else, which may or may not be pushing the amp past its limits, depending on the manufacturer, and the model.
\Staying our of your discussion cith commy, your assumption is incorrect. Whether the preamp stage is adding gain or not depends on the whole gain staging of the system, and 0 on the volume control just doesn't answer the question. For example, if my speakers are calibrated at 0 dB for reference, and somebody else's far more efficient speakers are calibrated at -10, the amp is putting out 1/10 the power at zero into the other person's speakers than mine. The point at which it goes from cut to boost in the gain stage has to consider the whole enchilada. Moreover, boost is only a problem if it either distorts the preamp stage, overloads the inputs to the next stage or causes distortion at the power amp outputs. The distortion will be exactly the same whether the levels result from a hot source and insufficient preamp attenuation or a cold source and too much preamp gain (assuming the preamp again is linear).
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post #46 of 50 Old 06-20-2012, 05:28 PM
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Quote:
Originally Posted by commsysman View Post

This whole discussion is totally meaningless, because the "0db" you are talking about is only a setting on your amplifer or receiver.
It has NO relationship to the actual SOUND PRESSURE LEVEL in the room!
"0db" on one system is different than another, because a difference in speaker sensitivity as well as the input voltage from the source charges everything.
If you are concerned about what is "SAFE" you need to get a meter that measures the actual SPL in the room, not a meaningless setting on your equipment.
For systems that are calibrated so that movie reference is at zero on the volume dial, this is simply incorrect. Zero wuld be the same SPL at the listening position from amp to amp and location to location, at least within the measurement uncertainty of the mics used. The differences in speaker sensitivities are accounted for by, uh, changing the speaker trims. It's what they're there for.

Absent such calibration, commysman's point is accurate (and oughta be self evident, but probably needs to be repeated at least occasionally)
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post #47 of 50 Old 06-21-2012, 05:40 AM
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Originally Posted by JHAz View Post

Instead you'll see a spec for voltage to achieve max rated output. And you might see the gain described in dB, because the amount of gain doesn't need a reference: the input signal IS the reference. 20 dB of gain on a .5 volt signal gives you a 500 volt output. 3 dB of gain on a 1 volt input signal gives you a 2 volt output.

I'm not sure if you meant to put it this way, but either way I'm going to clarify just in case

Voltage is a field quantity (a force). Wattage is an energy quantity. A field quantity (voltage, sound PRESSURE) will double with an increase of 6dB and an energy quantity (electrical watts, acoustic watts) will double with an increase of 3dB since it varies based on the square of its corresponding field quantity. With that, a 20dB gain on a .5v signal will lead to a 10x voltage increase (5v) and a 100x energy increase (wattage). I'm sure it was an error though considering that 500v from .5v is a 60dB increase! eek.gif


To add to the pot, I have my channel levels referenced to 0dB on the left front (which means I actually get reference with -7 on my system, considering speaker distance and sensitivity). During the night hours, I set the volume to -60dB for music and use my laptop's control to change volume for each song to avoid waking people on the other side of the wall up. For movies at night, -50. It seems odd to me that yours is so quiet even at 0dB. If I approach -20dB I'm probably headbanging or watching a movie loudly (violent door and window rattling across the house, etc). Weird. By the way, the numbers on my AVR aren't linear unless all processing is off. tongue.gif

...
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post #48 of 50 Old 06-21-2012, 06:29 AM
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When someone says "SAFETY", I assume they are referring to the safe levels that will not cause hearing damage.

The SPL that endangers ones hearing is a well-established factual matter.

Quote:
Originally Posted by master0068 View Post

Well this is an inaccurate statement as well. SPL is NOT an indication of "safety" as all amplifiers are unique and do not output the same level of volume.
The OP's question is completely valid, because below 0db the receiver is attenuating the volume, and above it is doing something else, which may or may not be pushing the amp past its limits, depending on the manufacturer, and the model.
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post #49 of 50 Old 06-22-2012, 08:51 AM
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Well this is why you shouldn't assume.

By safe, we mean for the RECEIVER.

Why would anything above 0db relate to SAFE for hearing, when it isn't indicative of actual volume?

People are trying to figure out the technical aspects of going above 0db for an amplifier, and if it causes dangerous stress to the amplifier.
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post #50 of 50 Old 06-22-2012, 09:43 AM
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Originally Posted by master0068 View Post

Well this is why you shouldn't assume.
By safe, we mean for the RECEIVER.
Why would anything above 0db relate to SAFE for hearing, when it isn't indicative of actual volume?
People are trying to figure out the technical aspects of going above 0db for an amplifier, and if it causes dangerous stress to the amplifier.

There is no 0dB "for an amplifier." There's only 0 dB when it's refeenced to something. For example, all digital recording references to 0dBFS (for full scale) (hottest signal you acn encode) and go down from there. You cannot exceed 0dBFS in a digital recording because the system can't go there. No bits left at the top of the range to encode louder

But 0 dB on a receiver master volume control has no meaning until and unless it is calibrated to mean something. Otherwise it;s merely a number. Once you cailbrate, whether you are boosting or cutting the previous stage's output at any given volume level depends on the way the gain stages are set up in the receiver, and on how the calibration come out.

Again, many modern receivers with autosetup calibrate so that reference equals zero on teh master volume. Without the reference calibration, the number on the master volume means nothing, either with respect to actual sound level or the power being output. You could of course test yourself using suitable test tones and know how loud 0 on your receiver is with a -20 or -30 dBFS test tone, and could refer that back to movie "reference." But unless you designed the receiver, or have studied the schematic closely, you are unlikely to be able to guess when the overall gain (versus the level of the input source) goes from cut to boost in your system. The more sensitive the amp input, the less preamp level you need to achieve any given output.

My Denon calibrates to reference = 0 on the MV. SO with a -20dBFS pink noise test tone, I'd get 85 dB from each speaker at my listening position. Let's say I take my Paradigms out (they're rated about 95 dB at one watt at one meter) and replace them with highly efficient horn based speakers (let's say 105 dB at one watt at one meter) and recalibrate. Calibrated, my new speakers will be equally loud as the old with any given program (or test) signal with the MV set at at 0 or -10 or -20. The point of and the result of the calibration is that SPL at the listening position remains the same referenced to the master vollume level (for any given program or test input). But the power being output by the amplifiers to reach those levels has been cut by a factor of 10 when I calibrated for the new more efficient speakers. So 0 on the MV might mean 200 watts for a 105 dB peak with the old speakers, but only 20 watts for the new.

By itself. zero on the MV simply tells us nothing about power output. . . . Which is why if you listen loud and are not certain you have plenty of power it makes sense to listen carefully for distortion to make sure you're not going to kill anything. Most modern receivers could be expected to go into a thermal shutdown before they were damaged by normal program material. But that's plenty annoying, if cheaper to deal with than frying output transistors.
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