db power of my pioneer Elite ?????

[moves]

I have an sc 27 Elite 140 watts/channel running Totem Forest with an SPL of 110 db...

How can I measure how many watts are coming out of my speakers at a given amplifier setting? i.e. -10 db.... -10db = how db regarding SPL.... I don't get why it says the negative number? What doesn't it just read the actual amount of db being produced?

 

[Pyrrho]

I have an sc 27 Elite 140 watts/channel running Totem Forest with an SPL of 110 db...

How can I measure how many watts are coming out of my speakers at a given amplifier setting? i.e. -10 db.... -10db = how db regarding SPL.... I don't get why it says the negative number? What doesn't it just read the actual amount of db being produced?

How much power it is putting out at a particular volume control setting is dependent upon the strength of the input signal. Since music varies in intensity, the power output will be constantly changing, regardless of the volume control setting.

In order for the receiver to actually show you the decibels being produced, it would have to have a power meter for each channel, and it would have to know the efficiency of your speakers and the acoustic characteristics of your room, or it would have to have a measurement microphone hooked up to it in your room. But even then, it would be dealing with the volume that is being produced at a specific point, and tell you nothing about how loud it is in other parts of the room.

 

[j_garcia]

You can pick up an SPL meter for $40 and it will tell you more or less exactly what kind of SPL you are getting.

 

[walter duque]

I have an sc 27 Elite 140 watts/channel running Totem Forest with an SPL of 110 db...

How can I measure how many watts are coming out of my speakers at a given amplifier setting? i.e. -10 db.... -10db = how db regarding SPL.... I don't get why it says the negative number? What doesn't it just read the actual amount of db being produced?

Are you saying you're hitting 110db with that Pioneer. Maybe I am not getting it, it's been long day.

 

[moves]

Are you saying you're hitting 110db with that Pioneer. Maybe I am not getting it, it's been long day.

no no lol my Totem's have a rated SPL of 110db. I just want to know how loud I ca SAFELY play my music without damaging the speakers.... since they are a tad expensive lol.

 

[moves]

How much power it is putting out at a particular volume control setting is dependent upon the strength of the input signal. Since music varies in intensity, the power output will be constantly changing, regardless of the volume control setting.

In order for the receiver to actually show you the decibels being produced, it would have to have a power meter for each channel, and it would have to know the efficiency of your speakers and the acoustic characteristics of your room, or it would have to have a measurement microphone hooked up to it in your room. But even then, it would be dealing with the volume that is being produced at a specific point, and tell you nothing about how loud it is in other parts of the room.

wow I actually knew that... I guess I just needed to hear it again lol. I just want to know how loud I can safely play my totems without damaging them... this is where my question originated from.

 

[moves]

I was stilll thinking.... this still doesn't answer my question on why the receiver displays negative numbers for DB? Why wouldn't it just start at 0?

 

[markw]

Those numbers are virtually meaningless.

Suposedly, they are when the amp is theoretically putting out it's maximum power given a specific input level before distortion theoretically sets in.

As others have pointed out, since the input level constantly changes. it's nothing more than a rough reference for a user to know where he/she can set the level to feel comfortable.

 

[MDS]

I was stilll thinking.... this still doesn't answer my question on why the receiver displays negative numbers for DB? Why wouldn't it just start at 0?

The negative volume display is known as a 'relative' volume scale (as opposed to an 'absolute' scale that ranges from zero to some max number).

Volume numbers, regardless of absolute vs relative scale, are meaningless unless you calibrate the receiver to a known output SPL given a known input level. This is what the test tones on the receiver (or on an audio calibration disc) are for. In other words, the volume numbers do NOT indicate anything regarding watts, SPL, or anything else.

The receiver test tones are pink noise (equal levels at every octave) and are at a level of -30 dBFS. If you calibrate the receiver such that the SPL at the listening position is say 105 dB (Dolby 'reference level') when the volume number reads zero and the receiver is playing that -30 dB tone, then you know at a glance that the SPL is 95 dB if the number on the display is -10 dB.
The caveat to that statement though is that ONLY when the input level is -30 dB because that is the level of the tone you used to calibrate. Movies have a wide dynamic range and at many times the level will be far below or far above -30 dB. CDs are much hotter yet.

Now many will try to explain that '0 dB' is the point at which the receiver will start to clip and sound bad, equating that point to '0 VU' on a VU meter. While that may be true, the label '0' actually means nothing - a receiver that uses the absolute scale (say 0 -80) will ALSO have a point at which clipping will occur if the input level is too high and you cannot make any kind of statement that 'x' number on the display will be that point (which is why others have already explained that it depends on myriad factors and not reallly worth fretting over).

As I've said many times before, the proof that there is no difference between absolute vs relative volume displays is in the manual for a typical Onkyo receiver. The manuals explicitly state that 82 on the absolute scale is equivalent to 0 on the relative scale. Switch back and forth between the two types of displays and nothing will change...

 

[KEW]

I was stilll thinking.... this still doesn't answer my question on why the receiver displays negative numbers for DB? Why wouldn't it just start at 0?

I have a circa 1978 analog amp with a detented volume knob marked in dB. All of the way up, it is marked 0 dB and at the bottom end it is marked -infinity with -60 as the first detent up.

I always assumed that this approach was probably decided by an engineer.
Whereas we tend to think of using a volume knob to increase sound, from the electronic standpoint a volume knob restrains the signal!
Replace a volume knob with a straight piece of wire and you would get 0dB alteration (the signal is not restrained). The volume control is then used to throttle back the signal.

For my old amp, I presumed that they chose an average speaker efficiency (for that time period) and assigned the markings accordingly.

Many of today's amps go up to 0dB, then continue to +10dB. I don't know why, but would guess that it was a marketing decision.

 

[popotoys]

no no lol my Totem's have a rated SPL of 110db. I just want to know how loud I ca SAFELY play my music without damaging the speakers.... since they are a tad expensive lol.

You can probably safely play up until clipping, which of course, you can't tell by the volume control. If you can hear distortion, you are more than likely far above clipping.

 

[MDS]

I have a circa 1978 analog amp with a detented volume knob marked in dB. All of the way up, it is marked 0 dB and at the bottom end it is marked -infinity with -60 as the first detent up.

In digital audio, -infinity is silence and corresponds to a bit pattern of all zeros. Likewise, 0 dB is maximum and corresponds to a bit pattern of all ones. Neither actually refers to Sound Pressure Level.

The scale on the receiver is using this concept to show you that when turned all the way up, it is amplifying the signal as much as it can or more correctly as you pointed out, it is applying zero attenuation to the signal.

The volume scale does not relate to SPL but remember that decibels express a ratio between two quantities. In the receiver's case, it is power. When the volume display says -60 dB, it means the receiver is attenuating the signal and the level is 60 dB below the max it could put out.

Many of today's amps go up to 0dB, then continue to +10dB. I don't know why, but would guess that it was a marketing decision.

I explained that above but no worries, it always falls on deaf ears. On a receiver with that scale, +10 is the maximum; ie zero attenuation. Once you calibrate to a known level, 0 means something and +10 means it is 10 dB higher than it is at 0.

The important point about all of this is simply this: Regardless of the scale, the receiver has a minimum and maximum range that it can amplify or conversely attenuate the signal. There is no difference between 0 to 100 and -80 to +20; they both represent 100 'steps' between min and max.

 

[KEW]

In digital audio, -infinity is silence and corresponds to a bit pattern of all zeros. Likewise, 0 dB is maximum and corresponds to a bit pattern of all ones. Neither actually refers to Sound Pressure Level.

Correct me if I'm wrong, but I thought the signal was analog by the time it saw the volume control. So are you saying that even though I feed an analog signal into my Marantz SR-6001 receiver and select "pure direct" to avoid processing, my receiver converts it to digital and applies the attenuation then back to analog to feed to the amp section? Or does it have both a digital and an analog volume function.
Wouldn't a bit pattern of all ones be a steady state on signal (which could never be a signal of music)?

I explained that above but no worries, it always falls on deaf ears.

If you check the time of post, you will see that I did not have the benefit of your post before I made my own.

 

[MDS]

Correct me if I'm wrong, but I thought the signal was analog by the time it saw the volume control. So are you saying that even though I feed an analog signal into my Marantz SR-6001 receiver and select "pure direct" to avoid processing, my receiver converts it to digital and applies the attenuation then back to analog to feed to the amp section?

Some do, some don't. Some receivers say they use a 'digitally controlled analog volume control' - whatever that means.

I was just trying to show the rationale behind the volume display scale and how they come from digital audio concepts but are not related to output SPL (unless you calibrate as described).

If you check the time of post, you will see that I did not have the benefit of your post before I made my own.

I wasn't referring to anyone in particular so sorry if you took offense. This topic comes up every so often and it seems hard to comprehend for some reason.

 

[M Code]

Now many will try to explain that '0 dB' is the point at which the receiver will start to clip and sound bad, equating that point to '0 VU' on a VU meter. While that may be true, the label '0' actually means nothing - a receiver that uses the absolute scale (say 0 -80) will ALSO have a point at which clipping will occur if the input level is too high and you cannot make any kind of statement that 'x' number on the display will be that point (which is why others have already explained that it depends on myriad factors and not reallly worth fretting over).

0dB level indication does in fact have a definite meaning.
This is an indication of its gain setting when a test reference signal is inputted (usually 1V RMS) and the amplifier outputs its rated power into 8 Ohms....

Just my $0.00..

 

[Pyrrho]

no no lol my Totem's have a rated SPL of 110db. I just want to know how loud I ca SAFELY play my music without damaging the speakers.... since they are a tad expensive lol.

Generally speaking, if you put on some music that is at a fairly constant level, and gradually turn it up until you start to hear distortion, and then turn it down until you cannot hear the distortion, that is the maximum safe volume you can play your stereo. However, this does not correspond to a particular volume control setting, as a higher input at that setting would cause the amplifier to try to put out more power, thus exceeding that level. So there is no position of the volume control (other than all the way down) that is going to be perfectly safe in all cases.

Whenever you hear distortion, turn it down (other than, of course, recorded distortion, as with many Jimi Hendrix recordings, which is not a sign that you are overdriving your amplifier or speakers).

Of course, there is also the issue of hearing loss, and with that, if you get headaches or your ears hurt from playing music, you are playing it too loud for your ears. In many cases, damage to hearing shows up years later, so some people foolishly suppose that they can listen as loud as they want without consequence. The simple fact is, old people can have excellent hearing, if they have not had problems with disease or loud noises. If you wish to continue to have the hearing that you have, or something close to it, you should keep the volume at a reasonable level.

You can search online for many articles regarding sound levels and hearing loss.

 

[moves]

Thanks for the info guys..... so I guess listening to something at 110 db will probably be too loud for enjoyment right? 110db are my speaker's SPL.

 

[M Code]

Thanks for the info guys..... so I guess listening to something at 110 db will probably be too loud for enjoyment right? 110db are my speaker's SPL.

110dB is way too loud!!
You will destroy your hearing. Suggest that you invest in the $50 Radio Shack SPL meter so that you can measure this level for yourself..

Just my $0.00..

 

[Pyrrho]

Thanks for the info guys..... so I guess listening to something at 110 db will probably be too loud for enjoyment right? 110db are my speaker's SPL.

That 110 dB is, presumably, at the maximum power input your speakers can handle. Typically, that would be at 1 meter (read the specifications for your particular speaker to be sure), and often one listens further away, so it is likely to be more like 107 dB where you sit (though obviously it depends on how far away you sit and your room acoustics, so it could be either more or less). That is loud enough to do damage to your hearing. There are many online sites with information about this; here are a couple:

http://www.sengpielaudio.com/TableOfSoundPressureLevels.htm

http://www.gcaudio.com/resources/howtos/loudness.html

It is important to note that how long you listen to something at a given level matters when dealing with sounds that do not instantly do damage. And the charts that you will find never really show safe levels; they show levels that are known to cause damage. Slightly less might cause some damage, but may be too small to find in any studies that have been done so far. Certainly, if you get headaches from the volume, or your ears hurt, you are doing damage. But you can still do damage at levels slightly below that.

If you exceed what OSHA advises, you will do damage, though you might still do damage at slightly less than what they allow:

http://www.osha.gov/pls/oshaweb/owadisp.show_document?p_table=STANDARDS&p_id=9735

http://www.osha.gov/pls/oshaweb/owadisp.show_document?p_table=STANDARDS&p_id=9736

Many rock musicians destroy their hearing from loud concerts (Pete Townshend of the Who is a notable example), and it also happens in many classical musicians who sit in front of loud brass instruments.

If you want to enjoy music in your autumn years, I strongly advise you to pay attention to these things while young. Except for extremely loud sounds, typically damage is noticed years after exposure. Remember that.

 

[highfigh]

The relative scale is just an approximation, based on the volume control range and where it should provide maximum clean power with a standard audio input. If -0dB is rated power, going over that will be louder but with high signal level, it will begin to distort. Most amps and receivers with a rotary knob hit rated power at about 1:00 and that's about as high as they should go unless the signal level is lower than normal. That last part, in italics, is the only reason they allow it to go higher. For the display to actually be accurate, it would be necessary to input the speaker's impedance, sensitivity and distance to the listener, so the receiver could calculate the SPL.

AS mentioned, 110dB will damage your ears, quickly.

Here's the OSHA specs for long-term noise exposure:

TABLE G-16 - PERMISSIBLE NOISE EXPOSURES (1)
______________________________________________________________
|
Duration per day, hours | Sound level dBA slow response
____________________________|_________________________________
|
8...........................| 90
6...........................| 92
4...........................| 95
3...........................| 97
2...........................| 100
1 1/2 ......................| 102
1...........................| 105
1/2 ........................| 110
1/4 or less................| 115
____________________________|________________________________
Footnote(1) When the daily noise exposure is composed of two or
more periods of noise exposure of different levels, their combined
effect should be considered, rather than the individual effect of
each. If the sum of the following fractions: C(1)/T(1) + C(2)/T(2)
C(n)/T(n) exceeds unity, then, the mixed exposure should be
considered to exceed the limit value. Cn indicates the total time of
exposure at a specified noise level, and Tn indicates the total time
of exposure permitted at that level. Exposure to impulsive or impact
noise should not exceed 140 dB peak sound pressure level.