dB scale is logarithmic, 4dB is a significant difference.

Significant in what sense? It's a lot of power but a 4 dB difference in SPL only equates to a 1.32x difference in perceived loudness. A 10 dB difference in SPL is required for a 2x perceived difference.

Or to put it another way, if you are down 4dB from your target you are loosing approximately 24% of your sound level.

Correct.

Or if you're an optimist you'd still have 76% of your targeted level.

For me it's a moot point as I have never had to turn it up that loud for music or movies. I do understand why some people might want more though.

I'd be interested in what others who are having loudness issues would measure using the same setup...

Your 7075 amp has 28 dB gain, 1 dB less than "typical." Not a big deal, but as long as we're splitting hairs.

I did a survey a several calibration discs, and whereas most do hit 75 dB, for some reason the DVE DVD came out at 73 dB. So if we add 2 dB to your 71 dB readings, you'd really be getting 73 dB (from other sources).

We can get another cut on that hair... IIRC 29dB gain is the "THX Certified" target whereas many amps shoot a little lower in the 26-27dB range... seeking a goldilocks balance between power, loop feedback, distortion, and stability.

Just an update on my output level problem...

I am using the 975 in stereo mode. After talking with Scott the output level issue with the Sony Blueray player was solved by changing the Sony audio output mode from Dolby to PCM. In my testing on a DVD and a Blueray disc the volume level I was getting at 0db is now available at about -10db, which should give us sufficient headroom. On my system I consider the problem solved.

GREAT NEWS!

Honestly the nearly infinite number of setting that the different digital devices deliver to the rest of the audio chain is DIZZYING and the negative effects of how some output format buried three pages deep in poorly thought out menus is infuriating.

Just because HDMI has made "physical connection layer" harder to get wrong the various setup items that manufacturers have "baked in" are still far from "goof proof". I wonder how many installation done by "certified installers" have various settings delivering sub-optimal sound / video???

Hello Outlaws,

I've been reading the posts on the max volume control and thought I'd weigh in. I too have the limited volume experience. I moved from a Model 1070, which ran my surround speakers with the 1070 serving as a preamp to a 2 channel Conrad Johnson MF2200 amp for my mains. The CJ is 200w into 8 ohms. Speakers are Kef iQ90 which are matched at 8 ohms and max at 200w with 91dB sensitivity. The source is a HTPC.

The only change I made so far was to remove the 1070 and add the 975 into the system playing only the mains at the moment. I'll be adding a Model 7125 for my surrounds when it arrives. I am still using coax between the HTPC and the 975 as I did with the 1070. No other changes have been made. Channel calibration is set to 0 for both mains.

I have not yet measured the volume with an SPL meter, but the issue I have is that the music's perceived volume is not as loud as the 1070. The volume indicator is in the single digit dB range when listening to music at less than concert levels. Not much headroom.

Since the volume does not go beyond 0dB my question then is: what is my incentive for purchasing the Model 7125 (125w) versus the 7075 (75w), or continuing to use my CJ amp (200w)? If the volume control has a maximum then I cannot take advantage of the power output of a higher wattage amp. Am I missing something here?

Regardless of the volume control the music is crystal clear with great hi's and low low's. I also love the 975's size and simplicity.

^^ What are your music sources? Are they analog or digital connections? Seems it must be low if you are running in single digits. I'm usually at -20 to -30 for normal. Perhaps you just like it loud!

Re: power amps, usually the reason for buying a power amp with twice the wattage is not the extra 3 dB in peak loudness, but in the quality of the sound at all levels. The improved sense of authority and control, or refinement it imparts.