Axiom Home Page Forums General Discussion Home Theater Yamaha db Display

I just purchased a Yamaha RX-V1300 and the Epic 60 system. This is my first foray into home theater. I have a question regarding the decible (db) level display on the LCD panel of the Yammi. When the volume is turned all the way down, it displays 99db and when it's turned all the way up it displays 0db. This is counter to what I would have expected. How should I interpret this information? From what I have read, I beleive that the volume of sound doubles with an increase of a few dbs (every 4-5 db?). But in the this case it appears that the dbs are decreasing as the volume is turned up.

Any insights will be helpful. Thanks.

That should be -99dB. It's 99 dB below reference, from what I understand.

Ya...my HK AVR325 displays volume levels the same way. Must be the new fashionable thing to do.

its a measurement of headroom. -99 means it can play 99 dB louder, 0 would mean its at its loudest and cannot play any louder. my kenwood receiver operates the same way.

Except that many CAN go louder. My Denon goes up to 30db above reference.

Thanks all. That type of display really does not give me much information. I would have liked to know what the db level is for a given amount of volume. Oh well...

That would depend on far more than your receiver can predict.

In reply to:

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That would depend on far more than your receiver can predict.

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Not so, with the Pioneer receivers featuring the auto-MCACC. When the volume is 0 dB on my 45TX, I am actually listening at the THX or Dolby reference level.

I don't think that's what he's asking for exactly. I think he means he wants it to display the real decibel reading for the output which is a bit different than its offset from reference.

However, it sounds like, from what you just said, this MCACC thing could in theory do that. I don't really know anything about that technology.

Is it basically some sort of ambient sound measurement hardware built into the receiver that allows for callibration?

Semi,

Yes, it is very simple in fact. The MCACC receivers come with a little measurement microphone, which you hook up to the receiver and place to the listening position. The receiver then generates a series of test tones, and automatically calibrate the response of the speakers and the room (levels/delays/EQs). In the process, the receiver leans how loud the speakers will play for a given volume level.

Do you guys know if reference level is 70db or is it relative to each receiver.

Sushi,

That's what I figured. I've seen similar setups with other, significantly more expensive manufacturers. It's definitely a cool technology.

My onkyo goes both ways.
It does the dB scale from about -60 to +10 i think and it uses a straight 0-100 scale as well.
Absolute and refernce scales i think they are called. Something like that.
On the 0-100 scale my reference level is marked at 82 when the volume screen reads 81, REF, 83....

The new HK receivers have a similar functionality, its called EZsetup, and the microphone is actually in the remote control.

Hi Amer, Avian, Chess et al,

Notwithstanding the Pioneer and H/K attempts to establish some kind of reference level, I do find this "calibration" of the front-panel readouts rather arbitrary and, for many users, counter-intuitive.

It stems from audio broadcasting standards, where "0 VU" on a standard VU (Volume Unit) meter on the control-room console actually was a standard calibrated level, so feeds from studios in different cities or locations would always be at the same level.

Above that 0-dB level, +3 dB indicated a distortion level of 1%, if memory serves.

But unless you clearly understand the logarithmic relationship of the decibel, it's confusing for consumer use.

By the way, amer, in acoustic sound pressure levels (SPL), it requires a 10-dB increase in sound levels to subjectively "double' the apparent volume. This requires an electrical increase of ten times. If a speaker needed 5 watts to produce a sound level of 90 dB SPL at 1 metre, and you wanted to subjectively double the volume, you'd need to supply 50 watts to the speaker to increase its acoustic output to 100 dB SPL. That's why slight differences in the rated power output of an amplifier really aren't very meaningful.

Regards,

Hi, this may or may not be the same as my Panasonic SA-HE70. Its volume also counts down from 99 to 0. Never having come across this before I emailed Panasonic customer service and got a reply back next day.

Being a mechanical engineer I know about decibels as a measurment of sound, but it turns out that decibels are widely used in electronics as well. It is simply a logrithmic scale describing a ratio for power, voltage etc.

Panasonic says in the case of my reciever it measures the decrease in resistance. The result is much finer control at lower listening levels where it doesn't take much power make a large change in sound level.

I would email Yamaha to get the official scoop.