if you can answer this i will respect you

[an1989dy]

why do db meters start at a negative number then go to zero then go to positive and are not equal increments on the lines?

 

[M.Brane]

The decibel is based on a logarithmic scale, and 0db on the meter is referenced to the threshold of hearing not absolute zero.

Are you sure you mean db meters, or are you talking about VU meters. They are something else entirely.

 

[EleKtriKaz]

0 on the db meter of whatever piece of equipment you might be looking at is the point at which the sound will cause THAT piece of equipment to clip. Different preamps or compressors or convertors have different db thresholds, and so their meters are calibrated specifically for that piece of equipment and do not refer to an actual decibel level of 0. Obviously whatever music you're recording is being played at levels much higher than 0 db. Someone correct me if any of this is wrong.

 

[masteringhouse]

0 on the db meter of whatever piece of equipment you might be looking at is the point at which the sound will cause THAT piece of equipment to clip. Different preamps or compressors or convertors have different db thresholds, and so their meters are calibrated specifically for that piece of equipment and do not refer to an actual decibel level of 0. Obviously whatever music you're recording is being played at levels much higher than 0 db. Someone correct me if any of this is wrong.

If you are talking about a digital peak meter, and 0 refers to 0 DBfs you are correct. If it's a VU meter 0 represents the "nominal" level or average level that you should be going for.

I believe the question refers to a VU meter. A 0 in this case is probably around 18 db below the clipping point (depends on equipment manufacturer).

The reason that the scale isn't linear is as described above, it's a logarithmic scale. The reason it starts as negative is that you are below the nominal reference level, at 0 you are at the reference, and plus when you are x DB above the reference level.

 

[Son of Mixerman]

How come were not talking about VU meters and the Db scale in electrical terms?

The reason the numbers are negative is because Zero Db is supposed to be 0.775 Vrms so any current below that will be less than .775Vrms right.
Db is often thought of as being a loudness measurement which is a subjective thing. VU meters are showing you an average where peak is showing you the maximum and the difference I believe it refered to as crest factor. Like Tom said the VU will read 18 to 20 DB below where the actual clipping is, but digital Zero is clipping. VU meters lag about 300ms compared to 10ms for a ppm, which means you should definitely know how to read both types when recording digital.

Here is an article that might help.
http://emusician.com/ar/emusic_meter_matters/

SoMm

 

[masteringhouse]

How come were not talking about VU meters and the Db scale in electrical terms?

The reason the numbers are negative is because Zero Db is supposed to be 0.775 Vrms so any current below that will be less than .775Vrms right.
Db is often thought of as being a loudness measurement which is a subjective thing. VU meters are showing you an average where peak is showing you the maximum and the difference I believe it refered to as crest factor. Like Tom said the VU will read 18 to 20 DB below where the actual clipping is, but digital Zero is clipping. VU meters lag about 300ms compared to 10ms for a ppm, which means you should definitely know how to read both types when recording digital.

Here is an article that might help.
http://emusician.com/ar/emusic_meter_matters/

SoMm

The actual voltage will depend on the load (ohms) but essentially yes. 0dBm is generally defined as 1 milliwatt across 600 ohms (.775V).

If you want to play around with this stuff, here's a cool little calculator:

http://www.analog.com/Analog_Root/static/techSupport/designTools/interactiveTools/dbconvert/dbconvert.html

Plug in 600 for ohms, 1 mW for power, and you can see the definition.

 

[Blue Bear Sound]

0 on the db meter of whatever piece of equipment you might be looking at is the point at which the sound will cause THAT piece of equipment to clip. Different preamps or compressors or convertors have different db thresholds, and so their meters are calibrated specifically for that piece of equipment and do not refer to an actual decibel level of 0. Obviously whatever music you're recording is being played at levels much higher than 0 db. Someone correct me if any of this is wrong.

It's all wrong... but both Tom and SofM already corrected you!

 

[EleKtriKaz]

Thanks...I didn't realize that I was wrong until you just pointed it out. Nope seeing their corrections didn't do it...I definitely needed you to point it out.

 

[Blue Bear Sound]

Thanks...I didn't realize that I was wrong until you just pointed it out. Nope seeing their corrections didn't do it...I definitely needed you to point it out.

No prob......! However, it does illustrate just how useful it is to know what you're talking about before you post it................!

 

[grinder]

Here's the simple explaination of dBs.

http://prorec.com/prorec/articles.nsf/files/EA68A9018C905AFB8625675400514576

 

[Son of Mixerman]

The actual voltage will depend on the load (ohms) but essentially yes. 0dBm is generally defined as 1 milliwatt across 600 ohms (.775V).

If you want to play around with this stuff, here's a cool little calculator:

http://www.analog.com/Analog_Root/static/techSupport/designTools/interactiveTools/dbconvert/dbconvert.html

Plug in 600 for ohms, 1 mW for power, and you can see the definition.

Hey now lets not get too technical Should we also delve into +4, -10, balanced and unbalanced? And using your ears to find the sweet spot the meters never tell you about?

Thanks for the link to the tool. Anything that does math without using paper and pencile is my friend


SoMm

 

[mshilarious]

Here's the simple explaination of dBs.

http://prorec.com/prorec/articles.nsf/files/EA68A9018C905AFB8625675400514576

I must have read that at least three times before, and this time I actually understood it! Woo-hoo!

You guys must be rubbing off on me

 

[EleKtriKaz]

No prob......! However, it does illustrate just how useful it is to know what you're talking about before you post it................!

Well, you know I wasn't trying to intentionally mislead anyone. I've actually gotten good answers for a lot of my questions on this board. I was just trying to answer a question that someone put out there. However, this illustrates to me how flaming can really increase your post count.