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[CraigNZ]

Is it possible to have the range of the volume control match the max volume level?  Currently it is fixed at 0 to 100, but if the max volume is set to 80 then the span of the slider is limited to 80% of the total width.

What I would like is to match the range of the volume control with the maximum allowed volume.  For example, if the max volume is set to 100 then the volume control range would be 0 to 100.  But if the max volume is set to 40 then the volume control range would be 0 to 40.  The span is always the same, just the max values changes from the fixed 100 value to the max volume level.

The reason for this is on my system I am using horn speakers which are very sensitive, connected to 150 watt amplifiers.  By setting the maximum voltage output of the DAC to match the input sensitivity of the amp you achieve the maximum dynamic range available.  But you would want to limit the max volume level in JRiver to say THX level (say 85 dB with 20dB headroom).  This might mean the max volume in JRiver is set to 40.  But the problem is the volume control span is very small making it difficult to set different listening levels.

If the full span of the control was always available then instead of having 40% of the span you would now have 100%.  In other words, full right movement of the volume control would still only be the max volume (40% in this example).

[6233638]

If you added a fixed attenuation in the Parametric EQ, you would be able to use the full "0-100" scale.
The control also responds to the mouse wheel when you are hovering over it, which I find useful to precisely adjust the volume level.

[CraigNZ]

Excellent idea.  So what I did was:

1. Reset all volume levels system wide
2. Set DAC levels so output level matched sensitivity of amplifiers (ie, max output = max input)
3. Looked up the sensitivity of each speaker.  For example, surrounds were 92dB, center 99dB, Fronts 105dB.
4. Selected least sensitive and used it as the baseline, in this case the 92dB rear surrounds.
5. Calculated that a 150 watt amplifier, at 0dBFS, 92dB speaker would generate 113 dB max SPL.
6. For THX max at 105, I would need a -8 dB attenuation so I added the attenuation in the PE and as the final step in the entire audio path.  In other words, it is the last thing done to all the channels before sending it to the DAC.  This insures that all previous audio processing steps had access to the full signal level.
7. Measured the speaker distances and entered them into Room correction.
8. Set the relative volumes using the speaker data.  So rear surrounds used 0 correction, center used -7 and fronts used -13.
9. Set max volume in JRiver to 100 and reference to 100.
10. Enabled loudness
11. Disabled volume protection

The theory now is the levels for each speaker should be correct and the overall system level at 0dBFS should be 105dB.  Or, if I use -30dBFS for the volume level (slider) and a pink noise then I should measure approx 75dB on my SPL meter.  Using the REW signal generator I can generate a pink noise at -30dBFS and set volume slider to 100.  Either way, I can measure each speaker to see if it is somewhat near 75 dB SPL (not allowing for room acoustic peaks and valleys).  Have not tried this yet as it was late and didn't think the family would appreciate me doing sound tests.  Will do it later today.

For the subwoofer I didn't have a sensitivity specification but I can use the SPL meter to dial it in.

[mwillems]

For the subwoofer I didn't have a sensitivity specification but I can use the SPL meter to dial it in.

The sub is a) very likely to be the least sensitive speaker (typical sub senstivities are in the mid to high 80's) and b) needs to playback 10dB louder than each of the other speakers to be "on spec."  Added together that's probably abut 15dB of "swing," so it's very likely that you'll need to rebaseline the whole thing with the sub as the new baseline, unless you have a separate amp for the sub with a significantly higher rated wattage (in the kWs).  

Otherwise that's an excellent methodology.

[CraigNZ]

The sub is a Definitive Technology SuperCube Trinity, it has a 2,000 watt amplifier (no substitute for horsepower).  I have it connected using the high level signal inputs and set the level control to 50%.  So far it appears to get the sub in balance with the rest of the system I have to use a -6dB attenuation, but will verify later today.  The sub is loud, with my previous system using Audyssey 32 it set the sub at -14dB attenuation after balancing everything.  The room size is approx 5,000 cubic feet, but even then the sub is probably an overkill for the room .. it has no trouble keeping up with the front horns at 105 dB.  I did have problems with the lights on that side of the room though, the sub shook the wall so much it kept breaking the filaments in the bulbs, so moved to wireless controlled LED bulbs which so far have done well.

[mojave]

Since you have an SPL meter I suggest you use JRiver's Audio Calibration to find the levels.

1.  Activate and open the Room Correction DSP and set proper distance settings
2.  Go to Tools > Advanced Tools > Audio Calibration and use Volume Calibration Mode and your number of channels. Press "Play" and not "Create Files."
3.  Play the tones and adjust the volume control so that the mains playback at 83-85 dB.
4.  Write down the SPL numbers for the rest of the channels. The sub should also be at 83-85dB using the JRiver test signal.
5.  Open the Room Correction DSP again and click "Set Levels from Decibel Meter" and enter your levels for all channels. JRiver will now automatically set the levels in Room Correction.
6.  Use Parametric EQ if you want a further reduction in SPL for all channels
7.  If doing #6, remeasure SPL of mains.
8.  Set Tools > Options > Audio > Volume > Internal Volume Reference Level to the volume percentage that now matches 83-85 dB.

[6233638]

9. Set max volume in JRiver to 100 and reference to 100.
10. Enabled loudness
[...]
The theory now is the levels for each speaker should be correct and the overall system level at 0dBFS should be 105dB.

This is wrong. Reference level in Media Center is fixed at 83dB.
If you're outputting 105dB at 100% volume, then you need to set reference level to 56% (-22dB) since the "reference level" setting is telling Media Center what volume level = 83dB.
 
 
I agree with the suggestion to use Media Center's built-in calibration tones and an SPL meter to ensure that everything is at at matched volume. Specs often lie.

[mwillems]

This is wrong. Reference level in Media Center is fixed at 83dB.
If you're outputting 105dB at 100% volume, then you need to set reference level to 56% (-22dB) since the "reference level" setting is telling Media Center what volume level = 83dB.

The loudness reference level calibration is the setting at which a -20dBFS pink noise clip plays at 83dB, not a 0dBFS pink noise clip (MC's internal calibration clips are -20dBFS).  So if he's at 105dB at 0dBfs, then he's actually only probably off by 2 dB (as a -20dBFS clip would play at 85dB).  But you're right without measuring it's hard to tell.

I agree with the suggestion to use Media Center's built-in calibration tones and an SPL meter to ensure that everything is at at matched volume. Specs often lie.

Measurement is the best way (although radio shack-style SPL meters can be a little flaky when trying to level match subs).  FWIW I've never seen a speaker with a meaningfully incorrect sensitivity rating, but amp input ratings are definitely a mixed bag, and sound attenuation over distance doesn't always work out the way Room Correction expects it to.  

So, I agree, OP: absolutely measure it all if you can (preferably at the listening position)

[dean70]

I never quite understood the reasoning behind the 83db reference (at -20db).  ? Everywhere else states 85db (at -20). http://www.thx.com/consumer/thx-technology/thx-reference-level/

[6233638]

The loudness reference level calibration is the setting at which a -20dBFS pink noise clip plays at 83dB, not a 0dBFS pink noise clip (MC's internal calibration clips are -20dBFS).  So if he's at 105dB at 0dBfs, then he's actually only probably off by 2 dB (as a -20dBFS clip would play at 85dB).  But you're right without measuring it's hard to tell.

Oh good catch. Not sure how I overlooked that.
 

I never quite understood the reasoning behind the 83db reference (at -20db).  ? Everywhere else states 85db (at -20). http://www.thx.com/consumer/thx-technology/thx-reference-level/

I'm not sure why either. But the Loudness calculation is based off a reference of 83dB, so you should stick to that.

[CraigNZ]

I will get on to those measurements tonight.

I thought the Reference Level was the dBFS level at which the loudness affect was disabled.  If Reference Level was set to 100 then it meant loudness was disabled at 0dBFS but loudness effect was increased as the volume was reduced over the entire span.  But if the Reference Level is set to 83 then it meant at -17 dBFS level (100 - 17 = 83) then anything above -17 dBFS loudness was not enabled, but increased for all levels below that.

Is Reference Level used for something else?  Or is my understanding of this incorrect?

[CraigNZ]

Carefully reading the posts above I think part of my confusion is based on how to set the reference level.  If based on volume is it:

a) the slider value (0 - 100), or

b) the dB value (100 = 0dB), or

c) the SPL value at 100 (105 db)

In other words, I have set 100 on the slider to equal 105 dB SPL (theoretically thus far).  I will adjust the speaker and system gain to make this happen.

Then, the max slider is set to 100

But the Reference level .. is that set to:

83 - (but how does it know that 100 on the slider is 105)?

17 - (this 100 on slider - 83) don't think this is right

22 - this is 105 - 83 , does it then assume that 100 on the slider = 105 dB?

[CraigNZ]

Okay, I think I got it now.

The Reference Level is what volume (%) will measure a 83 dB SPL.

So using the calibrated audio files (-20 dBFS) measure each speaker with an SPL meter and record.  Then enter this data into the Room Correction box at the bottom and the software will automatically set the relative levels AND set the Reference Level (calculated from the SPL readings).

I give this a try.