Cranked the system up to 0 and it hurt my ears . Wondering if any body knows how high on the + side the 990 and the 7500 goes. Using axiom speakers and the louder,the cleaner.

I think it tops out around +5dB or so, although the exact max apparently depends on the channel calibration (too much + trim may pull that maximum setting down some).

You can test without a source playing. My range is -76 to +8.

That's the same volume range I get too.

OK, I've been curious about this, too.

I have the same volume range, -76 to +8 db. So, does this mean, then, that -34 db is half the volume of my amplifier?

thanks,

John

A decibel is not a linear unit - it's logarithmic. That's the way the ear works too. Gonk could probably explain this better, but the point is that what the volume setting controls is the power delivered from the amplifier to the speaker. Of course this corresponds to the loudness of the sound you hear, but not in a simple way. A ten-decibel increase in the volume setting means a ten-times multiplication of the power delivered to the speaker, so if, for example, 70 db on the volume setting, while playing pink noise (equal energy per octave), represents one watt of power delivered to the speaker - and it might, depending on the amplifier, not the 990 - then raising the volume setting to 80 db would increase the power delivered to ten watts and lowering it to 60 db would decrease it to 100 milliwatts. And going on the same scale, 90 db would mean 100 watts and 100 db would mean your amp would be overdriven unless it's a 1000-watt monster, and your speakers would be smoking ruins (remember this is steady-state pink noise I'm talking about, not music!). But, you're asking, what does this have to do with how loud the sound will be? That depends on the sensitivity of the speaker. Outlaw hasn't released the figure for their new bookshelf speaker, but a typical level for speakers other than horns would be around 85 db for a 1-watt input. That's loud enough that 8 hours' steady exposure in a workplace will result in hearing damage. As for "louder" and "softer", people report hearing a 10-db change in the power delivered to the speaker - remember, that means 10 times as much power or one tenth as much, depending on which way you turn the knob - as being "twice as loud" or "half as loud". Merely doubling the power to the speaker (which is a 3-db power level change) is about the smallest change in loudness that's easily noticeable, though in lab conditions people in anechoic rooms with headphones can detect a 1-db power change.
So where does that leave your question? If "half the volume of [your] amplifier" means half the power output, then whatever volume control setting on the 990 drives the amp to its peak (and you and I DON'T know what that setting is), dropping the volume control setting by 3 db will actually drop the amp's power setting by 50%. Surprising but true. (And by the way, amplifiers output audio signals, not sound. Speakers turn those signals into sound. That means only the speaker's output can accurately be said to have volume.)
And reducing the volume control setting by 10 db will make the sound you hear about half as loud as it was before.
There's lots more one could say about this, starting maybe with the sensitivity of the amplifier, but that's enough confusion for one day.
Enjoy whatever you listen to.

I like Cheese




nice answer psyprof1

I agree,

an excellent explanation, psyprof1!!!

I hear what you're saying; thank you!

John

This thread makes me think of something I've always desired. I'm sure others have too. I often wish I had any sort of accurate way to determine the amount of wattage actively being output by my amp. Whether that's max, min, middle, or anywhere in between.
Oh well, the 7500 still gets the job done.

You can always use a device like the Kill-A-Watt to measure the power being consumed by the amp - it doesn't tell you how much of that energy is wasted as heat and how much goes to the speaker.

By the way, good explanation of a very slippery topic, psyprof1.

My Monster 3250 (amp) has a 3 displays on the front that show how many watts are being sent to each channel. I leave them off because the lights are a little much, but when I first got the amp it generally was always on 0. If I cranked it up, it might have gotten to 20 or so for explosions or the like.

Not sure if it's accurate, though I know other owners of the same amp have had the same experiences. Some Mcintosh amps have analog readouts, I believe...

Although there's a lot of expensive equipment one could purchase to determine exactly where their amplifiers begin clipping, the simplest and most fun approach might be to hook up a dual channel oscilloscope to the speaker outputs. Additionally, a sine wave generator could be connected to one of the preamp inputs. I'm oversimplifying here, but you would then slowly advance the volume until the point of clipping is reached. This is easily visible on the scope when you begin to see distortion at the top of the sine wave. Crank it up high enough and you'll turn that sine wave into a square wave. A lot of high frequency harmonics are generated at that point.

However, I do not recommend this tactic while your speakers are connected. Although dummy loads don't truly represent the dynamics involved in the interaction between speakers and the amplifier output circuitry, they are a better alternative than the possibility of frying the voice coils in the tweeters of your beloved speakers. I won't even begin to guess at how many burned voice coils I've seen over the years, all caused by cranking that volume control beyond the point at which the amplifier produced clean, undistorted output. No front panel LED's or meters are capable of displaying this amplifier 'red line' accurately.

I have in the past hooked a scope to the outputs of someone's amplifiers to show them just how much clipping takes place at the high volume levels they'd grown accustomed to using during movies. The distortion was obvious to my ears but not to theirs. They believed it was 'just part of the movie.' Once they had a visible picture of the peak output of their amps and about where that peak output occured on the volume settings they understood why the sound seemed to break up at higher settings. Their ears were telling them but they weren't understanding the why.

Although most audiophiles can sense the limits of their equipment, most newbies cannot. A visual demonstration can speak volumes.

On a typical receiver, advancing a round knob volume control past the 11 o'clock point will generally be putting you in the danger zone. However, with modern equipment and electronic controls with linear graph displays it is very difficult to tell. When not using integrated equipment it becomes even more difficult as various amp/preamp combinations can produce a slightly different 'red line'.

A couple of my Carver amps have level controls. If I set these to different positions and recalibrate my 990 the maximum achievable volume reading on my 990 will change. That's because I've changed the maximum power output of one piece of equipment in the chain. Recalibrating reset the maximums. I now leave the amp level controls fully clockwise because the amps without level controls are at that setting by default.

Just because the 990 will advance to +8 doesn't mean that I can safely play my system at that level. If I observe the amp outputs with a scope (and my ears!) visible distortion occurs well before I get anywhere near +8.

The only way I get my money's worth from my equipment to is use it within its limits. Determining those limits can be tricky.

Sorry to be so long-winded.

BobZoom

WOW! A lot of response on a -76 to +8. Didnt think about turning it up with no sound.****. Thanx for the tech. lesson.

I see that this is an older thread but maybe someone can tell me why my 990 goes from -76 to 0 (no "+" volumn, stops at 0).

I'm not certain, but I'd look at the channel trim settings to see if any are into the "+" range to any significant degree.

Just about any mainstream preamp today will put out something in the neighborhood of 7 volts AC maximum. This has nothing at all to do with the "range" of the volume control. This is far away more than enough to drive any home theater amplifier deep into clipping. Most home theater power amps have a target gain of 28db, and require anywhere between 1 and 2 volts to drive them to full power.

Most preamps have a gain roughly in the neighborhood of 20dB, so using this figure, if you have an input voltage of 200 millivolts (far less than most signal sources can supply - most CD players supply 2 volts), then the preamp should have the capability to drive this to 2 volts - enough to drive any amplifier into clipping. Taking the typical output of a CD player of 2 volts, then the preamp would try to amplify this to 20 volts - impossible to do. So in this case the preamp will be deep into clipping - however before this, the power amplifier will be deep into clipping.

By the way, most power amplifiers are around 60% efficient. Using a power consumption meter, you can figure the rough amount of power being made by the amp. Power amplifiers don't "waste" nearly as much energy as your car!

your pre amp must be defective.. mine goes up to +8 on the 990. it's never reached that kind of volume before.. but I have taken it up to about -5 or -3. that was dang loud too.

is this correct zero (0) would be reference level?

Hello skyblazer,

What are you trim levels set to in the speaker calibration menu?

Scott

fronts
Left 0
Center 0
Right 0

right surround +2
Left surround +3
Subwoofer +2

Oops, sorry about that Skyblazer! That questions was actually meant for Uncle Bill.

Uncle Bill,

What are your trim levels for each speaker in the channel configuration menu?

Thanks,

Scott

Mine actually goes to +14. On the 7.1 input anyway.
I'm having trouble getting audio out of an HD/DVD on an HTPC, so I cranked it all the way last night, just to make sure there was no audio. Funny, Bluray discs work fine (its a combo drive).

This is slightly off topic but I am hoping that the new 990 Pre/Pro has a max and minimum threshold you can enter so you can't accidently get to +8. My Harmony remote tends to have a mind of its own at times and will just shoot up to +8.

I couldn't agree with titleist more. I was having remote control problems when I had my choral group over to listen to our recording. All my equipment is in a closet, so it's not visible unless the door is open. I had people everywhere in the room, including right next to the speakers.

The CD had a long silent gap at the beginning. Thinking the remote was funky, I increased the volume without observing the display. It was at full blast when the music started. Carmina Burana begins at fortissimo with timpani, orchestra and choir giving it there all. At 200W per channel, it was incredibly loud.

I had a lot of people pissed off and it ruined the night. I am very fortunate that nothing blew up.

An overall limit is a necessity. Does it make sense to use the channel calibrate function on the 990 to resolve this? I would really like to see an overall adjustment added to 990 firmware.

It would also be very useful to have a gain adjustment for each input. Again, this would make for a rather simple modification for the 990 firmware.

You can buy limiters very cheaply from companies like Alesis at the Guitar Center. Set the maximum output you want, and the volume won't go above that.

the 990 also have built in a volume set level, so when you turn it on.. it's volume is set to a specficied volume. it works great.