Meridian Unplugged - Powered by MrTechGuy.co.uk Forums Discussion Meridian - Systems G68 volume: How does it work?

I've been reading the archives and I can't find a definitive answer to this question. My understanding is that Meridian's volume control is part digital, part analogue. A few points that I'm unclear about...

1. Does the analogue volume control only kick in at the top of the volume range, e.g., somewhere above 87? If that's true, does that mean that by keeping the volume at 87 or less, the analog volume control is out of the signal path?

2. Does the digital volume control result in bit loss? Or does the conversion from 16 to 24 bits allow for some attenuation without bit loss (for 16 bit inputs)?

3. Does offsetting during speaker calibration (to -3, -4, ...) have any affect on questions 1 or 2?

4. In light of all this... Is there a sweet spot in the volume range?

Thanks!!
Bryon

1. For best results, keep below 87. IF this is not loud enough, your speakers are too small for your room or setup.

2. No.

3. No. This has to do with proximity to the listener with reference to SPL.

4. Yes, no, and both. Sweetspot in volume would be listener specific, room treatment, speaker placement, calibration, and lastly recording specific. Simply put; there is no Meridian magic number. Shut your eyes, open your ears and listen. The volume that removes you from the room and puts you at the recording is the sweetspot.

Thanks for the input. Is your advice to keep the volume below 87 because that is where the analogue gain kicks in?

I'm not exactly sure what Meridian does in it's "HyBrid" Volume but it does appear to be some combination of analog and digital.

One hunch is they have 6dB of Analog Attenuation (possibly with a resistor network).

As you step through 6dB you hear nothing on each .5 dB, and then at each 6dB you can hear a click in the speaker output (Silence Playing with it cranked up loud ears to the speakers). It's like it shifted a bit and then brought analog attenuation back to 0 for another 6dB pass.

I don't know if they do the same thing all the way down.

I think there is a sweet spot.

I think part this is some how maintaining high S/N (into the analog amp) and high Dynamic Range (keeping the most significant bits your listening to in the high bits of the DAC) at "normal" listening levels.

I think this is partly why the +3dB trick makes things sound better. It restores this whole "Hybrid Volume" scheme to work as designed in DSP speakers.

I think this scheme was critical for 15 year old DACs (e.g. 14 bit DACs) but I'm not sure it's still needed with modern DACs but Meridian still does it.

Thanks, George. I listened for the "clicks" from the speakers with nothing playing. The result...

99
98
97
96
-click-
95
94
93
-click-
92
91
90
89
88
-click-
87
86
85
84
83
82
-click-
81
80... and below this I can't hear any clicks.

I did this several times to make sure I had the numbers right. Don't really know what to make of it, since the spacing between clicks isn't uniform.

Any ideas?

Just for info if that helps, 87 is full scale with digital sources.

Robert

That's interesting. In my setup, I control music volume with computer software upstream from the G68. So I leave the G68's volume at one setting.

In light of that, I've been trying to find a sweet spot to set the G68's volume. I've narrowed it down to either 86 or 87, which probably isn't a coincidence if 87 is full scale with digital sources.

I have that value from my 861v3 and from 565.
Play a very low signal or music and turn up the volume to 87, listen if the signal its not distorted untill you go o higher numbers.
But take attentation only use low level signals otherwise you dont need that test anymore...

Robert

So if done in software you sure it is not just lowering the digital out?

I must have been tired or distracted when I wrote my last post, because I said I used "software" to control volume, which isn't the case. I use SONOS to control volume. Basically, the setup is this...

iMac -> Sonos -> reclocker -> G68

My understanding is that the Sonos digital output is 24 bit, so it provides -48dB of attenuation without resolution loss. I use the Sonos handheld controller to navigate my music, so using Sonos' volume is very convenient.

-48dB of attenuation is more than enough for my needs, so I almost never touch the G68's volume, except for movies. Since the G68's volume is nearly always constant, I'm trying to figure out the best setting to leave it.

Sonos is 16 bit as far as I know. You might as well buy a Bose system if your gonna use Digital Attenuation on 16 bits.

You also don't have 24 bits of DAC resolution, no body does. So that's really a bad bad idea.

Sonos volume control is pretty good. Yes, it can only play 16 bit audio files, but that doesn't mean that internally or externally it does not use more bits. 16 bit in/24 bit out to 24 bit downstream devices potentially gives 8 bits worth of attenuation without any loss in resolution. I don't think thats going to affect anything other than at the lower end of the volume control unless your downstream devices are not going to accept and handle 24 bit input which the M kit can.

But in an ideal world, you would pass full range digital and attenuate at the latest possible opportunity.