No volume control when using digital source - Forum

Hello Markus,

Thanks for your post and purchase of Genelec DSP products. First, some general comments about the control of the volume in the digital domain.

Some users are afraid of quantization (reducing the effective digital word length when the audio data is attenuated) in the process of digital volume control. The point here is very simple. The data must be linearized by adding what is called dither noise into the data before quantization. This very efficiently linearizes the digital volume control and renders performance similar to any analog fader except that the digital one remains strictly linear also at low level, and there is no error in gain unlike with analog faders.

In Genelec DSP loudspeaker systems the DSP processing, including the volume control in the digital domain, have extremely high dynamic range so that nothing remains inaudible because of digital volume control.

Regarding your question, yes GLM must be installed and in use to control the volume. GLM can be controlled in different ways. For example, GLM includes support for Griffin Powermate third party knob. With this you can control the volume when GLM is running on the background. The Griffin Powermate knob features rotary motion for volume control, mute on quick down stroke, and bass manager bypass on long push–and–hold. Access to the knob specific functions definition is on a GLM the pull-down menu under the Setup Tab.

Now, from GLM version 1.2.0 there is also a new GLM Autolink application that can be used to control the volume and load system setups. In both cases GLM needs to be running but can be kept in the background.

Thanks for your feedback suggesting a small volume controller device connected to the DSP loudspeakers via Ethernet. We will carefully evaluate your request.

Best regards,

Hello Christophe,

thanks for your answer. Yes I understand that changing the volume at the source would be bad for the (digital) signal. The volume control has to be at the final stage of the processing chain. Volume information should be transmitted as additional information in the same signal stream, but it seems this is not part of the digital audio standard. What a pity!

Thanks for pointing to the Griffin Powermate also. This is a good enough solution until there is a controller device that does not need a computer and GLM.

Markus

Hello,

does anybody know whether the 3DConnexion Space Navigator can be used with GLM?

Markus

Hello,

Thanks for your post and question. Space Navigator is not supported by GLM. It has more functions than what Griffin Powermate features. But thanks for your question and for bringing out the need.

Regarding a small software, smaller than GLM or a separate piece of hardware that can be connected on the network, we will look into these options in the future. So, thanks for your feedback.

Concerning your earlier question on the Mac environment: there is the AutoLink feature in GLM (this requires the GLM software) which can be used to automate certain things, such as loading setups using keyboard shortcuts. In any case, in the Mac environment GLM does not need to be visible (it needs to be running in the machine, but can be hidden) in order to have GLM volume control on the loudspeaker network.

Best regards,

Hello,

is it also possible to control the volume with the Griffin Powermate when GLM is running on the background on a Windows PC?

Best regards
Thommy

Hello,

Thanks for your post. The Griffin Powermate allows you to control the system volume control exactly as you describe. GLM can be running in the background or open in the main window - in all cases the Griffin knob provides volume control.

Best regards,

Hello,

thank you very much for the answer.

Best Regards
Thommy

Hi
I recently read your article .Great post. And found some basic knowledge of "volume control when using digital source"Thanks for your post and question.
Once again thanks for your feedback suggesting a small volume controller device connected to the DSP loudspeakers via Ethernet. We will carefully evaluate your request.

Hi,

I am putting together a demo sound system in multiple rooms. I am using the 8260A monitors. For the digital source I would like to use the Sonos Zone player ZP90 http://www.sonos.com/whattobuy/zoneplay ... gType=1033

The specs on the Sonos only state digital output, coax and optical. I assume that this is SPDIF and I will need an SPDIF level to AES 3 conversion transformer such as this one: http://www.murraypro.com/spdif-tos.htm

My main concern upon reading this article is that I will not be able to control the volume by using the Sonos digital output. This would be a severe restriction for me. I am already purchasing the GLM system in order to store static room configuration, this is not a problem. The problem is that I need the remote and multiple room control as provided by the Sonos system. So i need to be able to control the volume using the Sonos digital output.

Is this possible to do?

8260A accepts and decodes an SPDIF digital audio signal. However, the characteristic impedance specified for SPDIF is 75 ohms and while 8260A has been built for the impedance of 110 ohms specified for AES/EBU digital audio. Because of this reason we recommend the use of an impedance matching transformer. The transformer improves the reliability of connection for long cable runs (less than 5 meters). You may be able to use SPDIF without the transformer when the interconnecting cable is really short, less than 1 meter. We recommend you always make the SPDIF cable as short as possible to improve reliability of data transfer.

I am not familiar with the volume control on Sonos digital audio outputs. I recommend you contact Sonos with that question. If Sonos is able to adjust the level of digital audio then you can use Sonos remote control for adjusting volume on 8260As. Sonos web site says they have the “variable audio output option” and I would take this to mean you can use Sonos to adjust the audio level going into 8260As.

If Sonos provides a line out with no level control then you need the Genelec GLM to adjust the listening level for 8260As.

You may be able to also adjust the level at the entry into Sonos from another audio programme source. This method will adjust the level for all receivers.

GENELEC
Aki Mäkivirta
R&D Manager, DSP products

One of my dealers in Melbourne has used 8250's in the past connected to Sonos controllers.

I recommended the systems use the variable analog outputs of the sonus, they have worked flawlessly. Yes it is another conversion, but the quality of the convertors in the 8200's are great.

Hope this helps.

Hi everyone,

I'm considering either a 8250a or 8351a purchase and I'd like to know if anyone has any experience of using the digital input of these monitors with an Avid HD Omni?

I like the idea of being able to keep the signal path from interface to monitor completely digital but is anyone doing this in practice and to good effect? If so, are you using the Griffin device and GLM or the Omni's own monitor controller or something else? Or indeed is it easier to come out of the Omni analogue and use another A/D?

I love some first hand experience feedback!

Kind regards,


Graham

Hi Graham

I get great results running a full digital 5.1 with 8260 fronts, 8250 surrounds and a 7271 sub.
8351 would be my choice today, but they were not available back then.
Other than that I wouldn't change a thing.
I love the fact that I can run my speaker cables as long as I like with absolutely no loss and they still cost nothing.

I'm an audiophile so Pro Tools and A/D is not for me.
My setup is:

MacBook Pro -> firewire -> Weiss AFI-1 -> AES 3 -> Genelecs.
For stereo I usually just run the 8260, as they extend down to 19hz in my setup.
GLM 1.5 and Griffin controls the volume / room compensation.
(Looking forward to trade up for the GLM 2.0)

This is insane value for money !!!

Many thanks for the swift reply!

Nice setup by the way I don't have much experience with GLM - do you have GLM set to open automatically on start up of OSX and do the monitors 'remember' the last monitor controller setting when you power down you Mac or quit GLM? Have you ever experienced any software glitches which resulted in 0dBfs being output through the monitors? How 'invisible' is GLM when you're using other applications?

Thanks so much for the insight.

Kind regards,


Graham

Hi Graham

I manually open GLM, as I use the Mac for other things as well.
The monitors will remember your default volume and DSP settings if you set the right DIP switch.
I have never had any software glitches that gave 0dBfs, but I have had some noise a few times.

I'm not sure what you mean by the invisible question.
However, I find I get the best sound quality and EQ by always using GLM as intended.
Even the few times I have fed the monitors analoge signals.

All the best

Peter Ring

Hi Peter,

I guess by 'invisible' I meant do you find yourself having to go back to GLM and tweak things or in practice is it pretty much open GLM and then forget about it and just use the Griffin? (I'm hoping it's the latter!). It's good to hear you've experience no software glitches. Can I ask is the default volume a value you set in GLM or is it simply where you left the volume last?

Thanks for all the info - so helpful.

Regards,


Graham

I guess by 'invisible' I meant do you find yourself having to go back to GLM and tweak things or in practice is it pretty much open GLM and then forget about it and just use the Griffin?

I start GLM choosing the needed calibration (in my case 1 point calibration, alternatively 4 point calibration if I have visitors) and only use the Griffin knob.
That's it.

Can I ask is the default volume a value you set in GLM or is it simply where you left the volume last?

You can save a default volume that is your startup value - every time.
I have set it rather low.

All the best

Peter Ring