Axiom Home Page Forums General Discussion Technical Questions Very Simple Question

On a multi channel receiver or pre processor, what are the volume numbers referenced to? Is there a standard?

For example, if my volume display shows -30 dB, what is it telling me for each of my channels?

Oooo, a test; we went through this just the other day!

Generally speaking......

Lets see now; The +10 point is where clipping may begin.

"0" is kinda like where all goodness resides, except on THX where it actually means some kind of reference point.

Ok, ok, I've been outta school for a long, long time! Might want to try a forum search!(or wait for a more in-depth responce)

Some recievers, like my onkyo, give you a choice: 0-100 and the relative +/-db scale. That's kinda cool.

Yeah, it's not standard between manufacturers. Usually, 0 is reference level, but this can vary wildly. For example, on my H/K, it says to calibrate at -15 to reference level. So who knows...

I was reading another board and one fellow was testing two different units. He made the comment that it didn't sound as loud with his new unit set at xx dB as his old unit set at xx dB.

I started wondering if it should sound the same??? My 7 year old Kenwood receiver has the volume scale in dB, but I never gave it much thought. If I wanted it louder, I turned it up. If I wanted it less loud, I turned it down. I didn't care what the dBs were!!

I guess that it is just another case of fancy gear displaying information that really doesn't mean much.

>>I guess that it is just another case of fancy gear displaying information that really doesn't mean much.

Bingo

As far as we can see, 0dB means something different depending on the power output of the receiver, ie 0dB on a big honkin' receiver is louder than 0dB on a little wimpy receiver.

I always assumed 0dB was some kind of reference output level (implying that a more powerful receiver would have more numbers above 0dB) but apparently that is not normally the case.

Yup, another theory of relativity; entirely relative to our own(audio)frame of reference.

Subsribe to the newsletter each month. You will learn a lot This was covered this month

http://www.axiomaudio.com/archives/June2005.html

A very simple answer:

Ahh…the mysterious zero db on receivers nowadays. It’s amazing how something so small can affect so many…or something. Many “experts” have many different “explanations” as to how the 0 point is derived by different component manufacturers. They are, of course, all wrong. All their talk of “clipping” and “headroom” is just fancy-lad talk for, “They wave their magic voodoo sticks of voltage over the thing as they cast the remains of long dead woofer spiders of divination and whatever the gods of audio decide – so let it be written, so let it be done.” The truth of the matter is as difficult to explain as it is easy to calculate. I’ll spare you the complexities of the mathematical figures (mostly because every time I look at the equations I flash back to my advanced thermalductionivity class and start flopping around on the ground like a fish – it’s a defensive behavior (much like a possum) that has got me out of more than one final) and I’ll use an analogy.

The 0 point on the receiver is much like a spring flower…a man eating spring flower. Well, technically, a woman eating spring flower. Ok, forget the flower…there are no flowers. Ok, let’s start again. This mollusk walks up to this crab….oh, wait, that’s a different one. Let’s go with the carnivorous gender hating bloom. The 0 point is like that. Understand? No? Hmmm….Ok, everyone knows that 0 is not very loud right? Right. You know that. Your wife knows that. Your mother-in-law knows that. Receiver engineers understand that you want things to be LOUD. For most of us, the louder the better. What better way to justify playing something LOUD than being able to say, “But honey, it’s only at -20!” I mean come on! -20? How loud can that be? And if it sends your mother-in-law running from the room…so much the better. See, just like a woman devouring spring flower. Sheesh.

Thanks for reminding me about Advanced Thermalductionivity class,(we used it big time in small jet engines bypass ducts)and that was back in the day of the Slide Rule.

We use the relative scale on our receiver cause my Mother-in-Law died many years ago. And my wife is much too sharp to be deceived for long!!

(Actually,...watching the numbers go Down while the sound goes Up, confuses..uh...Me!)

In reply to:

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we used it big time in small jet engines bypass ducts

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Really? That was that was about? I thought it was about how to get duct tape off of water heaters. I don't know. There was a cute teacher so I signed up for it but after an unfortunately slide ruling accident (involving rules that were apparently NOT made to be broken...like restraining orders and ...gravity) I ended up having to drop out. Intermediate sarcasm was open so I audited the class. Best move I’ve ever made….unless you ask my wife…or family…or coworkers…or, well, just about anyone.

ROTFLMAO!!!!!!!!

izub: thanks! I had not read that article. It answered some but not all of my question. Ironic that I would ask the question and there be this month's article on it! LOL!!

In so many words, I think that he said that the dB scale is referenced to nothing, and there is no standard!

I am sort of lost in the last part of the narrative where he recommends the receiver setting at 80 dB and then talks about the master setting of -10 to -15 dB and the then each channel to + 3 dB.

I think that a far simpler way (since all things appear relative) is to set your master volume such that your meter reads 80 dB SPL. Then go in to the individual channel set up and see what the readings are with pink noise. Take the highest channel reading and set all the rest to it.

Comments???

Had you stayed in class a bit longer you would have learned that the technology began with the installation of insullating adhesives on hot liquid vessels, AND yes, the removal of said tapes and the resulting laminar Delta Ts evolving into, well,...you guessed it....Thermoductionivity!

Hi RatPack,

It's really complicated and there is no direct comparison possible from the volume dB display on your receiver, which is referring to electrical changes in dB (it takes 10 times as much amplifier power in watts to increase volume levels so they subjectively sound "twice as loud") and actual acoustic Sound Pressure Levels (dB SPL) at your listening area as measured by the Rat Shack SPL meter.

If engineers were observing strict theory, they would calibrate the volume dB display (assuming speakers of a given sensitivity) so that when you cranked up the control to the "0 dB" setting, the amplifiers would be ready to clip. The amplifiers would be producing their maximum rated output just before distortion set in. But loudspeakers vary considerably in their rated sensitivity (how efficiently they convert electrical watts to acoustic output), which will affect how much power is drawn from the receiver.

You can't compare the dB readouts from one brand of receiver to the next. There is a consensus, however, that most engineers calibrate the volume display so that the amplifiers will be nearing their maximum output somewhere between -10 dB and +5 dB on the display. What that translates to in actual volume levels in acoustic dB, C weighting scale, measured on the Rat Shack dB meter at your listening seat in your particular room will depend on a host of variables: 1) the rated sensitivity of the speakers 2) the absorptive or reflective qualities of the room and its furnishings 3) the physical dimensions of the room 4) how far away from the speakers you are sitting 5) How many speakers are operating (just stereo, 5.1, 7.1) from the same A/V receiver, and other variables too numerous to go into.

In the days of analog recording and broadcasting, "0 dB" or "+3 dB" indicated when the signal being recorded (or broadcast) was at near-distortion levels. Analog tape recorders "clipped" fairly softly, so you could push recording peaks beyond 0 dB to +3 dB or more without gross audible distortion. The "0 dB" reading was a means of standarizing recording levels on tape among different studios, and also of preventing radio and TV station transmitters from overmodulating (distorting).

But digital recorders clip in a nasty fashion and you must never let the recording signals get so loud that they go over 0 dB on the input meters. Even so, it still happens.

I hope this is somewhat clearer. If you have everything set up OK with all your relative channel levels, and you are using speakers of average or better rated anechoic sensitivity (89 or 90 dB/1 watt/1 meter), then you can assume that by the time your volume dB display gets to the -10 dB setting or higher, things will be getting very, very loud and the amplifiers may be nearing their full rated output on peaks.

Finally, if your receiver display indicates "-30 dB", you can assume that you are quite a ways from pushing the receiver's amplifiers into distortion.

Regards,

Thanks Alan! That was a great explanation.

I don't think that I have ever had my receiver past the -17 dB level (whatever power level that may be), and that was more than plenty loud for me.

I appreciate your technical input!!!!!

ROTFLMAO

I'm sorry but you lost me with this one.

Rolling On The Floor Laughing My Ass Off

Alright you two, what was so funny about my post???

Maybe I should take up comedy?

Rat:
I think he was quoting YOU higher up where YOU wrote ROTFLMAO.

See all the problems I've caused?! NO SOUP FOR ME, ONE YEAR!!

Exactly! Some times I just don't get it. Better to ask and sound foolish than be a fool forever.

Or:

"Better to keep ones mouth shut and be thought a fool; than to open it and erase all doubt!"

My other favorite is:

"The only stupid question is the one that's not asked"

Hey! It's all good!

Or, for this Canadian holiday:

It's all good, eh!

OK, so now I'm more confused than ever. Which probably doesn't take much any more. Reading all the posts and thinking about how often I run my music at -15 to -10 or even louder, are my ears gone or is my system not set properly. I recently raised my fronts, center and sub to +3 and my surrounds to +5 through my receiver but haven't had a chance to test this difference yet. Hello.. what did you say?? I can't hear ya!!!

cgolf: bottom line is forget this discussion and just enjoy your system. The readings don't mean anything!!!!

If you really want to know how loud your system is, get a radio shack meter and measure it.

Have a GREAT weekend.

Your are EXACTLY right!!!

What I do, and it's worked well for me for years, is set the lowest reading speaker to "0" and everything else "up" from there.

Does ot help? I dunno, but at least I know I'm not attenuating anything, and I'm not asking any nondiscript and ununderstood(is that a word?)circuit to do anything heroic on my account.

That, plus the fact that my Onkyo can also be set to an absolute reading of zero to a hundred, and if I get up much past eighty, I get nervous.

And can't hear, either!!

>>OK, so now I'm more confused than ever. Which probably doesn't take much any more. Reading all the posts and thinking about how often I run my music at -15 to -10 or even louder, are my ears gone or is my system not set properly.

Like everyone else says, don't worry about it. I normally listen to music around -20 and movies around -10, but for "loud music" (when circumstances permit) I can end up close to 0dB and occasionally higher. This is on an HK630 in good condition.

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Like everyone else says, don't worry about it. I normally listen to music around -20 and movies around -10, but for "loud music" (when circumstances permit) I can end up close to 0dB and occasionally higher. This is on an HK630 in good condition.

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John I hooked up my Rotel amp & 80s to the preouts on the 635 and was getting high 90s on the spl with the dial set in the mid twenties on the 635 (stereo mode)...don't think I'd be able get it down to '0' without substantial hearing loss occuring.

Well, MINE go all the way up to 11!!! HA HA

I think everyone on this thread should have a SPL meter!!!! That way we would have "calibrated" readings instead of the numbers on the receivers/ pre processors which are almost worthless.

A +11 on my receiver would be very, very loud (if it actually goes that far?)! I probably couldn't listen to it for very long. But, that is on my system.

Agreed on the meter.

The volume is all over the chart depending on the source. Stereo in the -20s, dvds -15 to -20, tv -10 to -15. All to produce the same spl reading.

My receiver has a built-in function to try to keep the incoming signals at a similar level, but I'm hesitant to use it for fear of attenuating something important! But yeah, I'll bet that most of us have that particular problem of varying inputs!