Dumb question here

[shane_0_mac]

On my HK AVR 235 what does the -20 db mean? What I mean is if I go above above zero db will it hurt anything? I am still learning and do not have a clue what the -db means.

I listen to movies at about -10db and its perfect but if I want to really pump some musuc is it safe to go above zero.

Also I when I listen to music should I switch my mode to 5.1 stereo intead of Dolby movie?

Please help a dumbass out here

[billyjoe72]

Don't feel like a dummy. You can't learn if you don't ask. At one point in everyones life in this forum, they didn't know what db is. Another words, I'm buttering this message up to say I don't have a clue. I know if I'm next to a 747 and they fire it up that it would be loud. 130 db or so. I think. However, I don't know how it relates to receivers. But if you listen in 5.1 stereo, it should sound better than dolby.

I'll wait with you to see the real answer.

[Frzninvt]

It means you are 20db down from full volume/full output. When you reach "0" that is full tilt, some receivers go into the + side for an additional 10 to 15db.

I primarily watch movies in the -40 to -35 range and that is loud on my setup. During some music listening sessions with no one around I have gotten into the -20db zone and man it was awesome.

I hope this helps a little.

[colterphoto1]

It's just a reference. You can crank it up until your speakers distort, at which point you WILL be blowing sh!t up!. I've listened to my Yamaha Cornwall setup at +3 but it gets pretty ugly pretty quickly.

Most folks I know listen to HT at a reference point of -10 (Mr. Picky) to -20 or so. I would think that constant listening at 0 reference puts you pretty much into clipping too much of the time. You'd be better off with more powerful receiver or separates, or more efficient speakers (if possible).

Michael

[shane_0_mac]

Thanks guys so zero is full tilt, thats makes sense now

-10 is pretty darn loud if you want to know the truth. My receiver is only 50 watts per, so my -10 would probably be like -40 on a true 100 watt receiver. I will just stick to the -10 range and enjoy

P.S. Michael, did you get my e-mail this AM? Palyed golf after work last night and had a couple adult beverages and got in way to late, I will measure and weigh everything tonight

[Northshore]

I have often been puzzled by the -db as well. It really depends on the system and the room setup I have discovered. In the theater I have the Adcom 7 channel amp and for HDTV -30db is moving some sound, but watching a movie my reference is -20-23db. I dropped it down to -11db on the Asteroid scene from Epi II and it brought the house down. Downstairs the Yamaha stays at -40db and pushes the old KG's just fine. In the end, it is what your ears and system can handle. My 1.5 cents.

[jacksonbart]

Its is definitely just a reference, the best way to tie it back to real decibels is use a sound pressure meter like, radio shack offers one. It will vary with the source obviously. My receiver will go as high as +18, but I would never think to kill it (clip) or my ears. I find on average with sources that its around 100 dB at 16.

[colterphoto1]

For real fun, you've got to turn your receiver's on-screen display off during movies, that way you can punch up the volume during BIG PASSAGES and blow your friends away!

Picky to me: "you're going to feel a change in the air pressure" OMIGOD!

[jacksonbart]

Picky is a maniac. I read the post about your visit and I am very impressed by his HT. You both seam like very good people. I also know from posts that he and you both has a very good sense of humor.

Cheers

[colterphoto1]

yeah Shane, got yer mail. You guys go have fun Saturday and we'll let UPS do the driving, okay?

Michael

[IndyKlipschFan]

shane_0_mac

Let me lay the Sack Down on ya....

-50 Stephanie Mc Mahon, Trish Stratus, almost a tease and hint of what is yet to come...

-40 is like Rey Misterio, The Hurricane ... It is cool, it allows you to hear most of your system, and does some cool tricks..

-30 Is like Eddie Guerro, Curt Angle, Edge.... Starting to come to life.... feels good, pops are there...

-20 Now your talking BIG intro music John Cena, The Rock, Batista, Tripple H, In your face sounds wonderful larger than life wow factors big slams...Explosions, and your excited and glued to the screen.

-10 Sometimes too much, can't watch for long, just might be too loud..(yes possible) Mr Mc Mahon...LOL..

0 (start of Smackdown Fireworks) if you have a true 200 watt system do you REALLY want all of that 200 watts Continuous WPC even if it does not blow something?? With high efficient speakers "Screaming at you" for say 2 hrs+?? It is just uncomfortable, trust me, even if you can!

I do miss the old days when it was just 1-10...10 was max...

Or 11 was just toooooooooooo much... Hahahahahahaha Spinal Tap!

That, and -20 on a 10 watt underpowered sytem, is not the same as -20 on a 200 watts into Seven Channels Aragon 2007 separate amp too. LOL

[sivadselim]

----------------

On 5/5/2005 10:04:12 AM jacksonbart wrote:

It will vary with the source obviously.

----------------

yes, it's just a reference. one of the biggest variables will be the distance your speakers are from your ears, as well as the size of your listening space. -20dB on one system is not the same as -20dB on another.

[shane_0_mac]

Indy,

I love that post, and I will take one Stephanie McMahon to go please

Triple H will just have to whoop my arse and get over it.

I actually dont think I will go over -10 it does sound awesome there to me.

I love this board, you can always get good ansers here

[DTLongo]

I have a 2005 HK AVR-235 receiver and really like it with my Khorns + Belle + RS-35's HT setup. Of course, the Khorns and Belle are very efficient loudspeakers.

The 00 Db level is a manufacturer's reference level for "full nominal power." On the AVT 235 you can go up beyond that to +8 or +10 but you should have your ears on and listen carefully for any distortion and if you hear any, back off.

With my setup, -10 is normally "very loud." On some low level program input material, I find myself nudging the 0 level or slightly above. For example, the classical audio-only music channels on my cable provider are at a lower level than the regular TV or HDTV channels, for whatever reason.

Bottom line: let your ears be your guide. Go to 0 Db or beyond cautiously, and if you hear distortion, back off.

[tkot]

----------------

On 5/6/2005 1:25:18 PM DTLongo wrote:

The 00 Db level is a manufacturer's reference level for "full nominal power." On the AVT 235 you can go up beyond that to +8 or +10 but you should have your ears on and listen carefully for any distortion and if you hear any, back off.

Bottom line: let your ears be your guide. Go to 0 Db or beyond cautiously, and if you hear distortion, back off.

----------------

just an edjamakated(sp?) guess on my part but the 00 db is most likely the point where the preamp output level is at what the

designers have deemed is the max clean output of the preamp.

if you push past this limit you may over drive the preamp on louder passages.

the 00 db referance on a 5 volt preamp would not be the same as on a 4 volt preamp in terms out output voltage to the amps.

jay

[Amdek]

I wrote the following a long time ago, in a galaxy far, far away...Well for a website that is long since dead. Should give you a leg up on what dBs are really all about.

There are many ways to talk about and explain sound. We can say it is dry, flat, bright, dull, muddy, brilliant, and many other descriptions. Terms such as that are intangible when it comes to the next guy, one mans perfect sound, is another's mud. These kind of descriptions can be helpful and can be used as a basic guide, but other terms like a dB (deci-Bel) can be given an exact scientific definition. Knowing what such terms mean is helpful, not just for helping us to pick out and compare components, but it also helps to understand how we hear.

A Bel is a standard of measure, named after Alexander Graham Bell. A deci-Bel is one tenth of a Bel. So what is a Bel? Well, a Bel is the logarithm of an electrical, acoustic, or other power ratio, the key being power. The formula for this is Bel=log(A/B) with A and B representing the two levels being compared. Since, in sound issues, a Bel is really too large a number to work with, they wanted to use something smaller and went to a dB, which changes the formula to dB=10*log(A/B). To help put this in non-tech terms, dBs are used to measure how much more or less we have of a certain thing. In this case how much more or less of an acoustic power or signal level, referenced to a certain level. dBs can be used in a variety of situations when talking about consumer electronics, whether it is voltage, wattage or SPLs(Sound Pressure Levels). I will point out that a dB is a dB, whether it is talking about volts, watts, or SPLs, how we figure the ratios is somewhat different, but in the end a 1dB increase in voltage, is a 1dB increase in wattage, is a 1dB increase in SPLs.

Now to apply this to our components, first comes voltage. I start here because this is ultimately what drives our speakers and components. It is also the one that throws a curve ball at us in relation to the formula. Now if you know Ohms Law, you know that power is proportional to the square of the voltage. Since the dB(power) = 10*log(A/B) formula is for power ratios, the voltage formula changes to dB(volts) =20*log(A/B). Lets apply this to the real world. The average CD player puts out about 2V (volts) with the maximum signal recorded on a CD. With the 2V given, if I said that a particular CD' s average level output on the same CD player is about .6V, how much below the peak level of 2V would the average be? 20*log(2/ .6)=10.4 dBs. This is just a small example. The point is that if you know two voltages you can determine the difference in dBs. Also if you follow the formula, doubling the voltage will yield a 6dB increase, but this is not so with wattage.

How do dBs correlate to wattage? Well, since watts are a measurement of power, we can go back to the dB= 10*log(A/B) formula. When looking at receivers and power amps, marketing and salesmen types love to throw out numbers like this or that has this many watts, but it really means nothing until you get that broken into dBs. Take an 85 watt per channel receiver, and a 110 watt per channel receiver. Based just on the manufacturers specs we can determine the exact difference in dBs between the two. Before we do, I want to make it clear that just because there might be the smallest of differences in dBs does not automatically mean that the component with the smaller wattage is just fine. It should come down to how clean one sounds over the other. Ok, putting in the above numbers you get dB=10*log(110/85). That calculated out equals 1.1dBs, not much difference at all. To get a noticeable perceived difference in volume, you need about a 3dB increase; 1.1dBs falls well short of anything significant.

That leads us into the discussion of dBs and SPL. The human ear needs that 3dBs more to perceive a noticeable change in volume, and to perceive a doubling in loudness we need an increase of 10dB. Now going back to wattage for a moment, to get 10dB more in terms of watts, you need ten times the power. While you digest that for a moment, you also need to know how speakers are rated in relation to dB SPLs. A speaker usually has a rated sensitivity somewhere in the manufacturers specs. This measurement as an industry standard is taken with a 1 watt input at 1 meter away on axis with the tweeter. The average is about 90dBs. That tells us with one watt of power at one meter away the speaker will produce a SPL of 90dBs. So if the same speaker is driven by a 100 watt amp, you would use the following formula dB= 10*log(100/1), the 100 being the one hundred watt amp, and the 1 being the one watt to obtain the given sensitivity. With that plugged through the calculator, you come up with 20dBs. That, in turn, means that if this speaker is driven with 100 watts of power, it will reach 110dBs at one meter away. The relation of dBs and distance can also be used to help determine how loud that 110dBs might be at say twice the distance. This falls under the inverse square law. Basically, all you need to know is that in a reflective-free environment, if you double the distance you lose 6dB of sound pressure. So at 2 meters that 110dBs is now only 104dBs,but in the real world we don't live in a reflective-free environment so the drop most likely won't be exactly 6dB.

To close, a few things are very important to remember about dBs, volts, watts, and SPLs. First, just because one power is higher than the next, does not mean it is significant, but at the same time if the lower-powered device does not sound as good as the higher-powered one, the difference in dBs won't matter either way. Also remember if you are dealing with manufacturer specs, the variance of some manufacturers overrating their equipment's ability or in some cases underrating its ability needs to be factored in. Next, the more headroom the better, but in some cases too much headroom is complete overkill. How and where dBs are referenced to is also important. When I say a SPL meter reads 90dBs, that means that a sound is 90dBs above the threshold of hearing. With CD's, Full Scale Digital (a maximum recorded signal) is referenced to 0dB. Anything below that becomes a minus dB from the stated reference point. In the long run, it helps to remember where the reference point is. Understanding dBs and how they relate to our components, speakers, and ears is important, and I hope this humble column has started or increased your knowledge on dBs.

[colterphoto1]

Shane,

How are you liking the HK HT receiver so far. I recently bought a HK 430 1977 receiver and it cooks! Was wondering if your experience with the HK HT stuff was the same?

Michael

[dragonfyr]

The problem, as you see with many of the posts, is due to several factors.

One, the 'dB' isn't a 'thing', its a ratio. Two, the decibel can be referenced to many 'things'!

dBm, dBV,dBv(dBU), dB, etc! I suspect that the reference is to dBv, as there is no way for the manufacturer of a receiver to have any idea regarding the efficiency or impedance of the speakers and thus to provide a measure of the actual loudness. It makes more sense that they would provide a reference of the output of the unit relative to some 'defined' reference point.

My guess is that they are refering to the dBV - the dB referenced to RMS voltage. 0dBV is a voltage reference point equal to 1.0 Vrms. -10dBV is a standard audio line level for consumer and some pro audio use, equal to 0.316 Vrms. RCA audio connectors are a good indicator of units operating at -10dBV levels.

Is this vague? Sure! As I have no idea as to what that reference actually is!

Here are listings and explainations and examples of some of the common uses for the decibel:

http://www.google.com/search?hl=en&lr=&oi=defmore&q=define:dB

http://www.google.com/search?hl=en&lr=&q=define%3AdBm

http://www.google.com/search?hl=en&lr=&q=define%3AdBv

[shane_0_mac]

Michael,

So far I am loving the HK. For what I paid for it I do not think I could ask for more. For only 50 watts it drives my speakers very nice. It has all the bells and whistles that I could ever use. I would recomend HK to anyone. I would say in the future when upgraditist hits again I will go with something more powerful but I am sure I will go with HK again

[psg]

On 5/5/2005 9:38:23 AM shane_0_mac wrote:

Thanks guys so zero is full tilt, thats makes sense now

-10 is pretty darn loud if you want to know the truth. My receiver is only 50 watts per, so my -10 would probably be like -40 on a true 100 watt receiver.

Actually, h/k receivers are rated pretty conservatively. But -10 dB on your receiver corresponds to -13 dB on a 100W receiver (if calibrated the same way for 0 dB at full output). So you see that spending a huge amount of money for a few more Watts doesn't make that much sense.

Using the AVIA calibration DVD and a sound pressure level (SPL) meter, I found that "theater reference level" is -17 dB on my dial, which is very loud. I usually watch DVDs between -30 dB and -25 or so, rarely at -20 dB. We Klipsch heritage owner have lots of headroom!