Better Volume Control

Can RAAT transport 64 bit floating point to the endpoint when doing DSP volume control in combination with Core DSP engine? Or does the output of the DSP get downconverted to 24 or 32 bit for transport over RAAT and then reconverted to 64 bit on the endpoint to perform VC attenuation?

I can read my path, and the signal is resampled to the original bit depth (if you have no upsampling engaged) when its sent to the RAAT.

A post was split to a new topic: Can I have volume control of my Roon on phone?

I followed the discussions regarding the quality of Roon DSP volume control.
The discussions revolve around whether it is better to use the device volume, the DAC volume, or an analogue volume control.

My concern was to find out the truth about DSP volume control in Roon by measurements just to know and to let you know.

Please see my results here:
The final truth about DSP Volume Control in Roon | Audio Science Review (ASR) Forum

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@DrCWO - do you know whether I can use the rooDial and upsample things to DSD? It appears when I try to go the DSD route the rooDial no longer works. And I like the rooDial a lot.

Would you please send me a screenshot of the device settings. Maybe you use DSP volume?

@danny Is there any possibility for Roon to license the Leedh volume control (digital) implemented by Lumin? It’s received rave reviews. I say this with full knowledge that perhaps I am way off base in terms of this thread! :wink:

I do use DSP volume in ROON with rooDial - I assume this is required to use the rooDial - Is that correct?

ROON Support has confirmed that if I upsample using DSP I can no longer use the DSP volume control.

I am not at the system now to send a screen shot.

If your playback device has a device volume control you also can use this with rooDial. Just select it in the device settings.

@Daniel_Flashman Also the Leedh volume control can be used with rooDial. As far as I know the “Leedh” is nothing else but the volume control of the ESS-DACs inside the Lumin streamer. Please let me know if I am wrong…

I have a Pass Lab Preamp that controls the volume and a Denefrips Venus ll DAC. I just selected ‘Device’ control on the Devise Setup. The rooDial will respond to turning but it doesn’t change the volume when I am using DSD or anything else in the ROON DSP options. When I disable all other DSP options in ROON the rooDial works fine. Sadly, it seems it is one or the other- rooDial volume control or Usampling in ROON.

I’m I missing something?

That is indeed incorrect.

Lumin actually allows you to choose between two kinds of volume control. For analog output of X1, T2, or S1, you can choose the on-chip standard 32-bit ESS volume control (with Leedh setting off), or the Lumin proprietary Leedh implementation that takes advantage of hardware architecture (with Leedh setting on).

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Quite Interesting,
in this case I wonder what Leedh processing stands for? I am not interested in marketing speach but in technology behind it. Is there any material you can share? If necessary I am willing to sign a NDA.

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Hi Peter,
I thank you so much for your information.

I got, that needing less bits and despite of that having a perfect volume control is the idea behind Leedh volume control. great :slight_smile: I also understood the advantage of this approach implementing volume control in silicon :+1:

Would you please explain why this should be better as calculating volume with floating point math as Roon does with its DSP volume? Doing volume control in a CPU I don’t have to care about additional bits!

Here are some measurements I took regarding this topic and I have no idea where volume control might be improved above that:
The final truth about DSP Volume Control in Roon | Audio Science Review (ASR) Forum

I wonder how the graphs would look like measuring Leedh volume control?

Best DrCWO

If I understand this correctly, a fundamental assumption is that the least significant bits in traditional calculation, although mathematically accurate, become noise due to the DAC hardware limits.

Whether this is true or not can only be verified by subjective listening tests. So far the majority feedback by reviewers and users are really positive. A few users even sold their preamp after being satisfied with this free firmware upgrade (but costs EUR5000 from another manufacturer).

As described above, Lumin allows you to choose the traditional 32-bit volume done by ESS vs the Lumin proprietary implementation of Leedh Processing Volume for analog outputs. It is designed in a way to facilitate A/B comparison if you have a Lumin. Users can determine for themselves whether this is audibly superior or not.

Peter,
thank’s for your answer.

Yes, this is my assumption. So having a digital volume control where noise is far below the DACs (and even worse the amplifier’s) noise this seems to be OK for me.

For sure I understand that reviewers have to listen. I also did at a friend’s home who owns a X1 and the Lumin AMP.

My question just was about objective measurements and if an improvement can be seen there?

Best DrCWO

Hi, in terms of absolute Sound quality, what’s the best way to control volume? My amp doesn’t have a volume control…my two options are either to do volume control via my DAC (digital I presume) and keep Roon core at fixed volume or to keep my DAC in Pre-amp mode and control volume via the Roon app on phone.

Which one should sound better? I often can’t tell a difference so wanted a more informed answer.

Thanks

If you can’t hear a difference I would do what’s easiest for you. Asking other peoples opinions will lead to dozens of different answers, none of which relate to your system in your room.

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Some DACs support analogue attenuation. What DAC do you have?

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