I have had my 990/7125 Combo set up for a little over a week. Seems the first night I set it up I could have sworn I set the volume in the -40 -35 area for DVD's Now I am in the -30 -26 -20 area for King Kong. Yeah I know things are relative but I am using very efficient speakers and figure I should be getting blown out of the room at these settings.

Mains Klipsch CF-4's 102db at 1w/1m
Surr Klipsch CF-1's 96db at 1w/1m
Center Klipsch KLF-C7 99db at 1w/1m

Just wondering if something may be up. FYI I did talk to Steve at Outlaw today and he had me go through setup again and even after that the volume seems a bit weak to me. Just looking for some comparison numbers from others with this same combo.

TIA

Joe D.

I listen to DVD's at around -18 and my speakers are Axiom M80ti's. It's loud, but not blow me out of the living room loud.

-30 to -20 doesn't seem out of the ordinary.

Axiom M80ti
SPL in Room 1w/1m(dB): 95 dB
SPL Anechoic 1w/1m(dB): 91 dB

Using my Kenwood speakers and 100w X 6 channel amp, I listen to DVDs at around -12to15db and TV at around -30db. -10db is about as loud as I get, but rarely is it that loud.

I have the 990/7700 combo running 2 channel with Paradigm Studio 100s. -25 to -20 is nice for sitting and listening to music. I cranked up some Metallica the other day. -10 is WAY loud. In fact I went outside to answer a phone call and was very surprised at how loud it was outside with the door shut. Mwaaahahahahahah.

I watch TV around -35dB to -30dB (start-up volume is -35) and watch DVD's at around -20dB. If I'm alone in the house, DVD's tend to drift up to around -10dB.

I watch TV around - 22 to -25, DVD's around -20 to -16.. and about the same for music in 2 ch.

Thank you to everyone who has replied. You have no idea how good it feels that it's not just me!

"This amp goes to 11..."

Seriously, there are so many variables/factors in this (including user calibration) that you really can't compare one system to the next.

I have very efficient speakers (Klipsch Cornwall mains, Klipsh Heresy side/center), and around 6000W of amplifier (big rack of Crown PSA-2's, most of them bridged).

I have configured the system (amp gains, cal settings) so that "loud" is in the -20db range. Goal, in part, was to maximize signal to noise ratios. If I ever decide that I want the system to be able to go louder, it will be easy to achieve :-).

I wouldn't worry about it-

Well, if you calibrate two different systems to the same reference level (so that they both produce a 75dB test tone when the volume is set to 0, for example), then even if one uses super-efficient horns and another uses very inefficient speakers you should get the same SPL levels when the volume controls are in the same position. The only difference would be how much power one or the other is using.

Now if you calibrate the systems differently, then obviously comparisons are going to be difficult or impossible. With the combination of speakers and amps that you have (and with those speakers I can't imagine the Crowns ever getting even a little warm), it would be easy to calibrate so that -20dB is reference - in which case you could take other people's preferred volume settings and subtract 20 to get a reasonably comparable volume in your system.

I use Rotel 200RMS x 5 channels amp with 990. Volumn is 1-12 for DTS, but -9 for DD on normal DVD watching. I crank up to 0 once a while.

CD listening is -15 or sometime down to -20 depending on how "congested" the music is.

Kwok

Sorry, mis-typol. volumn is -12 for DTS.

KWOK

Gonk speaks thusly:
"Well, if you calibrate two different systems to the same reference level (so that they both produce a 75dB test tone when the volume is set to 0, for example)... you should get the same SPL levels when the volume controls are in the same position."

Sure, that makes very good sense. The flip side, as you say, is that without equalizing the callibration like that, different systems will have comfortable volume settings that are all over the map. Doesn't really make sense to ask "what's your volume level for movies"?

I think we're saying the same thing.

You do raise a point I've wondered about though: is the db volume 'scale' really linear as suggested? If system A produces 75db test tone at "0", and system B produces 75db test tone at "-10", should we expect them to still be the same at A=-10, B=-20? The reason I wonder has to do with system calibration; and trying to decide how important it was to do the level cal's at or near typical listening volumes. If the db scale is truly linear, then it shouldn't matter at all.

And yeah, you're right, the Crown amps are enjoying an easy life of leisure these days; well deserved after years of much harder concert duty.
Can you say dynamic headroom boys and girls? ;-) The only one that get's a workout is probably my sub amp, driving what I think to be a 2ohm load (bridged amp driving 2 4ohm drivers in parallel).

Redrob,

Audio is logarithmic. Every +6dB is twice as loud, and every -6dB is 1/2 as loud to the ear.

If the display is showing actual dB changes, then lets say:

System A: 0 = 75dB
System B: -6 = 75dB

When we turn System A to -6 and System B to -12, each has gone down 6 dB, and thus is half as loud as before. Also since we know the calibration amount, if the display is dB accurate than we know they both will be at 69dB.

Also with your sub amp. 2 @ 4 ohm drivers in parallel are a 2 ohm load. When bridged, the amp sees half the load, so you are giving the amp an effective 1 ohm load. Good thing it is a Crown, few other amps could survive that.

Yeah, redrob, I think we are saying the same thing - we can eliminate some variables from the equation by using consistent calibration techniques, but there are other variables (particularly things like the movie being watched and the individual's preferences) that will insure that we don't all get the same answer.

As for the question of the decibel scale, it gets complex pretty quickly. The scale is actually logarithmic, which makes acoustical analysis all the more interesting, but for the sake of this discussion the answer is yes - if I calibrate at 0 and you calibrate at -10, then my -10 and your -20 would be equivalent (all we've done is move the "zero" point). This all reminds me - I need to go through some recent seminar notes and update my technique for HVAC acoustical analysis. Maybe in a couple weeks...

At the risk of further complicating the already complex, I've read in psychoacoustic research that for listeners to report one audio stimulus (most likely a single tone in lab situations) as "twice as loud" as another there must be a 10-decibel difference in terms of power delivered to the transducer (probably earphones). If that relationship holds for real-world listening situations, "twice as loud" as a 1-watt average power level to the speakers will be 10 watts, "twice as loud" as that will be 100 watts, and 99.9% of us can't afford "twice as loud" as that.

Very true. A 10dB increase is considered "twice as loud" but requires ten times as much power to generate. Doubling your power input yields a 3dB increase.

Actually when you do the math, it comes out to 6dB being twice or half as loud. It does require 10x the amount of power though. gonk is also correct that 3dB is double the power.

If that doesn't make sense, just remember that this is all logarithmic. It is based on curves. Each additional dB is more than the previous. Here is an article with way more info than you may have ever wanted.

But either way, even if calibrated differently, the two systems could be correlated volume-wise if we know what the two calibrations used are. If I set up with 0 on the display set to 60 dB speaker output and someone else set 0 to 80 dB output, then setting their system to -20 dB on the display should reasonably match my system's volume. What is really pertinent about this is that this will be the case if the 990's display is measured via dB and not some other arbitrary system. As long as we are comparing dB to dB adding and subtracting reasonably works.

I haven't run back through the math, but every source I've seen that relates perceived loudness (not actual power level) to decibel increases equates 10dB to a doubling or halving of loudness. Here's one summary that I've seen on more than one occasion:

• 1dB: Imperceptible Change
• 3dB: Barely Perceptible Change
• 5dB: Clearly Noticeable Change
• 10dB: About Twice as Loud
• 20dB: About Four Times as Loud

I'm not saying that these values equate to actual sound power (or intensity), but they are pretty widely-used guidelines for how people perceive changes.

Wife is gone for 6 days time to find out what loud really is with this combo.

Hmmm- armed with this new info, and looking at the back-end of my system:

http://tinyurl.com/rd6kz

I'm just not sure how I'm go about trying to get 10X the power; when I decide it needs to be twice as loud ;-).

Fill a room up with amps and buy stock in the local power company?

Sweet rack setup.

What exactly is the equipment in the rack?

Whoa, if you are really running 2 ohm load to that subwoofer with the amp bridged you probably haven't pushed it pretty hard. It isn't rated for anything under 8.

Crown's do a great job of protecting themselves, if you give them too little load they will just mute (and the IOC lights come on) on any of the older models (I have a DC300 Series II in my studio). The newer ones continue playing, but sound distorted as heck once you get below 1 ohm.

I would ask if you were sure they were parallel, but someone with that rack of amps should know the difference between parallel and series.

I just discovered Crown has the service manuals and schematics for all the discontinued amps for download on their site. That rocks.

gonk:

I hear 10 dB tossed around in some circles as well. I have a degree in sound design and in every class I have attended or taught, we have used 6 dB as the half/double. That matches up exactly to what you see on equipment. It is possible that if you take a measurement of actual air pressure coming off a cone it may line up more with 10dB being double, but that wouldn't correlate to what you see on your 990 display.

3 dB is considered the minimum amount of volume change to be noticed by most people with average hearing, although in my personal experience a great many people can hear smaller changes than that, even those often not discerning about what they are hearing (not mentioning my wife specifically....). This is a rule of thumb and depends on relative factors.

The rack houses 7 Crown PSA-2 amps. Spec's are here:

http://www.crownaudio.com/pdf/legacy/k1071-8.pdf

I like 'em. I've owned one of them for ~15 years, driving my main speakers, and just recently (after buying the 990), upgraded all of my amps to them... found a sweet deal on a group of used ones.

Even though I'm not pushing them very hard, they will warm up a room. Plus, they do elicit some cooling fan noise; so getting them into a separate room (storage room shares a wall with my theater room) has proven to be a good move. I ran 3 20amp circuits from my breaker box, and hooked up individual switched outlets for each amp (switches are near the 990 and other equipment- so I don't have to go back into the storage room to turn them on/off.

To help describe how I'm using them, here's the "front" side of my system:

http://tinyurl.com/en4ml

Amp 1: left main (915W into 8ohm)
Amp 2: right main (915W into 8ohm)
Amp 3: center (4 ohm, 2 8 ohm speakers in parallel; ~1400W)
Amp 4: sides (hanging speakers), stereo; 275W X2 @ 8ohm
Amp 5: rears (not visible in picture, on floor behind and to the side of love-seat: stereo; 275W X2 @ 8 ohm
Amp 6: Sub. It's the coffee table looking thing back in the corner with a lamp on it. Home built cabinet, using 2 4ohm 15" Cerwin Vega Drivers wired in parallel. Not sure exactly what the power for the amp is in this situation- somewhere around 1800W would be my guess.
Amp 7: spare. Not hooked up right now.

The top piece of equipment in the rack is a Perreaux PMF-1850 power amp. Also not in use at the moment. Might sell it. Might keep it as a backup. Might use it somewhere else. Haven't decided yet. It's way too nice of an amp for garage duty; but doesn't pack quite the punch that a PSA-2 does.

With the exception of the little rear speakers, all of the others are Klipsch Professional/Industrial models, with fuse protection, heavy duty drivers for increased power handling, etc.

We had our King Kong premier last night- good fun.

I have enjoyed and been informed by the previous posts and a couple of questions come to mind. When I calibrated my system I set the 990's volume at "0" and used the manual test tone function to set each channel at 75db. I have tweaked a couple of individual settings (up a db or two for example) but nothing drastic. Now the questions based upon a simple condition: playing a CD in 2 channel mode.

1. When I play a CD using Upsample at -30 on the 990 volume I get 80 to 85db at my prime listening position using my SPL meter C weighted and Fast. At -20 I get 90 to 95db; Discussions above about volume settings of -10 to 0 make me think noise induced hearing loss. I imagine there might be some variability due to individual systems but do my results when playing a cd seem reasonable to you guys?

2. When I adjust the left or right channel a db or two in stereo or other 2 channel mode I can hear a difference in the location of the stereo image. I can easily tell that it moves left or right. Since I can hear the change is the 990 truely changing the calibration for an indvidual channel by a single db or am I missing something?

1. your cd seems reasonable to me. how loud is -20 on your system? Do you like it loud or what?

2. Do you have your speakers toed in at all? A slight toeing in can improve the soundstage quite a bit. Not much toeing in is needed.. just a slight amount.

*although not a big deal at all.. use the "slow" on your SPL meter.

AVFan,

There are a couple reasons that you may see increased dB readings over your calibration. First off is that if calibration used a slow response (i.e. RMS or 'average') then that will show up a bit lower volume than fast response (i.e. peak). With sine waves RMS levels tend to be around 70% of peak levels.

This can be exacerbated by how CD's are mastered. Their average to peak values are reduced via limiting and compression. While the peak values should not get any higher, the average values do which makes them sound louder and puts more sound energy into the room.

For your second concern, slight volume changes are one of many clues the brain uses to figure out where sound is coming from. While a typical person may not usually be able to hear a 1dB change in volume from a single source they still will be able to interpret this change (and smaller) in the situation you tried.

When we discussed many people not discerning a 1dB change, you would have to change the level of all speakers that amount, or the inputs, to test that. The problem with testing that is that one becomes more sensitive when they are doing the adjustments, and they can lead themselves to believe they are hearing what they aren't. Basically when you adjust the levels you become more aware of it and it makes the test not as accurate. In some cases since you know you are adjusting things you will fool yourself into hearing a change that is imperceptible. To properly test this you would need someone else making changes where you couldn't see them.

Shawn,

I'll have to check the info that came with my SPL to see what the slow response setting actually does (e.g. RMS or average) versus the fast response setting. Regardless, I used the slow response setting for calibration and when I played the cds in stereo, so I'm not sure the fast/slow setting is a reason for the difference.

My sample of cds was pretty small when I made the measurements I noted above, but I don't recall their being a real significant difference in volume between cds. Yes, there is some variability (in particular one George Winston cd stands out as louder than others in my collection) in how loud cds sound.

I agree that if all the speaker volumes were increased 1db it would be hard to tell, but as I think you noted, when only one is changed it stands out. My second question was, or should have been, what volume change is noticable when only one speaker is adjusted? I notice the difference (e.g the "location" of the singer drum, specific instrument location) when a 1db (as noted on the setup screen) change is made to the left or right channel in stereo even when the master volume is at -30. Or another way:, When I make a 1db change on the setup screen do I really get a 1db change assuming -30 master volume that equates to 80 to 85db at my listening position? Sorry for the number of variables.

Something I just realized that would have greater bearing than what I said before is what level is being calibrated to 75dB at 0 on the display? For instance if you use Avia or DVE to calibrate a system, they output a pink noise and have you set it to 75dB. But that is not at full output, it allows for peaks well in excess of 100dB. Off the top of my head I don't know what output the 990 would use as its noise level, but it probably wouldn't be 0dBFS (decibels Full Scale, the loudest one can do in a digital signal). But likely there is some headroom involved.

As for what volume change can be detected when you adjust one of many channels, there is not an easy answer. It depends on the material you are listening to, and the person listening. It should be well under 1 dB, maybe as little as .3 dB, but there are a lot of variables involved.

The easiest to hear, and hence the smaller change needed to notice, would be a sound that is recorded well and the panning location can be heard, especially something like a vocal in the center of the image. As soon as a small amount of adjustment is made that sound will seem to move toward the louder speaker(s). Similarly if you add a slight amount of delay to one or the other the sound will seem to come more from the side without the delay. This is a function of how our brain works.

Now if you have a system that doesn't image very well, or a recording with issues so that the imaging is rather blurred, you can probably make a bigger change without noticing. Unfortunately I can't just say something like, 'oh, yeah, it is .564 dB.' Sorry.

Oh, and for the very last part of your post: If the 990 is truly working in dB (which it sounds like it is) then yes, no matter what the master level is set to, if you adjust 1 dB, that channel will change by 1 dB. It only gets weird with equipment that uses arbitrary and/or weird level indications. My current receiver behaves like the scale it shows is linear. That can lead to some real confusion!

Thanks, Shawn. When I calibrated my 990 I used its internal test tones. I have the DVE disk but I have not used pink noise from it to set the audio. M&K recommended using pink noise (one speaker at at time) to align the tweeter to the primary listening position; they said it would "snap" into place (Skyblazer noted something similar). Looks like I have two reasons, speaker alignment and volume to reference, to break out the DVE disk.

The ability to distinguish less than 1db changes between speakers is one of the reasons several gunslingers (including me) would like to have 0.5db versus 1db increments in the 990 speaker calibration. My old receiver had that ability and it was particularly helpful when fine tuning the center channel.