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8260A : Digital Volume control without GLM software (?)

ensoniq, modified 6 Years ago.

8260A : Digital Volume control without GLM software (?)

Padawan Posts: 47 Join Date: 5/30/15 Recent Posts
Hello,

I consider to buy a the 8260 and one last question came to my mind : can I control the volume of the speakers when fed by the AES signal from my Master-DAC which supports the controlling of the digital output with a Volume-Knob (?)

please forgive me if this a silly question but I heard that the Volume of the Genelec DSP series can be controlled by the GLM software connected with the 8260 through an ethernet cat cable only . Without the software connected to the MOnitors there might be no way to controll the 8260s volume .

can someone please comment or clarify ?

thanks a lot :-)
avantmidi, modified 6 Years ago.

Re: 8260A : Digital Volume controll without GLM software (

Youngling Posts: 15 Join Date: 5/28/15 Recent Posts
Good question. I ordered the 8351. I am waiting for the 8351's to arrive.
I was thinking that the volume knob on my Apollo 16, which can be set to also control the volume of the AES/EBU output (mirror output 1&2 = Stereo Bus), will then function as my monitor volume controller. This should work. Basically i'm asking the the same question as you are asking. Thanks.
ensoniq, modified 6 Years ago.

Re: 8260A : Digital Volume control without GLM software (

Padawan Posts: 47 Join Date: 5/30/15 Recent Posts
ok Avantmidi, so lets wait for the Genelec pros to answer ;-)

btw_ I want to control the volume levels via a Metric Halo ULN-8 and Oppo 105D via app
ilkka-rissanen, modified 6 Years ago.

Re: 8260A : Digital Volume control without GLM software (?)

Yoda Posts: 2564 Join Date: 3/23/09 Recent Posts
Hello both,

Of course it is possible to adjust the volume at the signal source, assuming that the device is capable of adjusting the level of a digital signal (not all are). It is also true that if you want to control the volume using the built-in volume control inside the speakers, you need to have the control network connected and the GLM sofware active. It is our recommendation to adjust the volume through it because that way the adjustment happens after the DSP processing, right before the signal gets converted back to analogue for the power amplifiers. That is the most ideal place in the signal chain to make the attenuation without any quality loss.
avantmidi, modified 4 Years ago.

Re: 8260A : Digital Volume control without GLM software (?)

Youngling Posts: 15 Join Date: 5/28/15 Recent Posts
Thanks for the explanation!:)

This is a quote from the Apollo 16 manual:

Monitoring:
• Digitally-controlled analog monitor outputs maintains highest fidelity
• Digital AES/EBU outputs can be set to mirror the analog monitor outputs


So I guess in this specific case there is no loss of quality/degradation because of the Apollo's digital volume control implementation correct? Since the AES output mirrors the analog stereo output?
I assume this way the digital signal leaving the Appolo gets inside of the 8351's in max fidelity without BIT loss of degradation?

Please see the attached screenshot!
ilkka-rissanen, modified 6 Years ago.

Re: 8260A : Digital Volume control without GLM software (?)

Yoda Posts: 2564 Join Date: 3/23/09 Recent Posts

So I guess in this specific case there is no loss of quality/degradation because of the Apollo's digital volume control implementation correct? Since the AES output mirrors the analog stereo output?
I assume this way the digital signal leaving the Appolo gets inside of the 8351's in max fidelity without BIT loss of degradation?

Hi,

In general people are way too scared about digital level control (attenuation), I am not sure who/what has caused this. Sure, one will always lose bits while attenuating digital signal, that's a fact and there is no workaround it, but when done correctly, it can result in more linear and as least equally noise-free operation as analogue level control. I'll attach here a reply from our R&D Director, Dr. Aki Mäkivirta who replied to another customer via email on this very same subject.


There are two principal ways of adjusting the sensitivity: using the DIP switch user interface and using the GLM software user interface and a computer connection to the monitors. I recommend the latter because the computer connection allows much much more versatile and flexible control than the DIP switches as well as automated room response calibration.

With DIP switches offer 12 dB + 30 dB attenuation using the rotary control and DIP switches, respectively. The GLM software allows -60 dB input sensitivity control in 0.1 dB step precision as well as 100 dB of volume control in addition to this. As you wee, using the GLM software for controlling and setting the 8351 is much more flexible and versatile.

Volume control always works in the digital domain. It is totally linear and does not cause any loss of signal quality. We have gone to extreme lengths to ensure that the signal processing inside the 8351 as well as the digital-to-analog conversion have so low noise level that they do not limit the dynamic range. The internal noise level of 8351 is low throughout the whole gain range. Theoretically, it is possible to maintain the dynamic range of the DA conversion if a noise-free attenuation can be done after the DA conversion. In reality there is always some analog noise, in the attenuator as well as in the analog power amplifier section after that. However, these have been optimized to so low that they are inaudible at normal listening distances.

You say that "every 6 dB of attenuation corresponds to a loss of 1 Bit, so a maximum attenuation of 42 dB would result in a loss of 7 Bits, bringing a 24 Bit recording almost down to CD level (16 Bit)". The essential question here is (1) is the system linear after digital attenuation, and (2) is the idle channel noise level low enough to not be audible. In the case of 8351 this is the case, and analog attenuation will not bring any additional linearity or lower the noise level. If I say this in other words, digital attenuation in the case of 8351 does not render any detail inaudible that would not be inaudible anyway once the listening level is set to a given level. The ultimate limiting factor is the human absolute hearing threshold. There is no degradation when using the level controls in 8351. This is my technical explanation of how the system works. I also encourage you to go and listen to 8351 yourself to experience how it works.

Best regards,
Aki Mäkivirta
R&D Director


Monitoring:
• Digitally-controlled analog monitor outputs maintains highest fidelity
It means that the analogue level control in done via digital controls, not for example via an analogue potentiometer.

• Digital AES/EBU outputs can be set to mirror the analog monitor outputs
Output mirroring means that the Lynx software mirrors analogue and digital out faders so that you can use either ones for level control. But it has nothing to do with the quality of attenuation.