Lumin, Leedh’ing the way

From a Lumin X1 user: Lumin X1: Enabling an Even Simpler Yet Better Sounding System | What's Best Audio and Video Forum. The Best High End Audio Forum on the planet!

I'd call it greater clarity and immediacy, lower-yet apparent distortion, together with larger-yet soundstaging in all dimensions and more solid imaging--the usual audiophile desiderata. This effect seems audible on all signals from low-quality internet radio streams up through high resolution programs.
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Even at extremely low volume levels (didn't want to wake my sleeping spouse, of course!) of between 8 to 10 on the 100-point volume scale ("normal" high volume for me in this system is about 72 or so), the added clarity and transparency were amazing. It's like I suddenly had Quad 57s or some other speaker known for extreme transparency even at very low volume levels.

The Leedh volume processing can be toggled on and off at will within the Lumin App for comparison. The switchover takes less than five seconds. Thus, pretty good A/B testing of the Leedh processing is available. (This assumes, of course, that Lumin has not somehow "dumbed down" the volume control when Leedh is not engaged in the new firmware. There's no way to quickly A/B the new version of the firmware with the old version.) The difference is the proverbial "night and day." And this is even though the direct connection before seemed surprisingly sonically purer than using the special relay-controlled volume control of my Benchmark HPA4 "preamp" which I thought was pretty special indeed at the time.
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The combination of upsampling/resampling everything via Roon's DSP engine to DSD 512, Leedh Volume processing by the Lumin X1, and the elimination of the DSD to PCM filtration in Roon has enabled my system to push past some threshold into a realism I've never before achieved. On much program material, there is an absence of artifacts and a see-through realism which allow me to suspend disbelief to an extent never before possible. This is even true for much low-bit-rate internet radio material.
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Re: Leedh Processing Volume free upgrade

Still haven't got round to testing this.
Is there anyone with a passive preamp that has tested this?
Your thoughts?

Sent from my Swift 2 Plus using Tapatalk
 
Re: Leedh Processing Volume free upgrade

Peter..so the 'Max Volume %' in the Lumin 's app should be set all the way to the left...or '30' on my app..but not all the way over to the right at 100...?Volume control - On...Leedh Processing volume -ON...I take my Lumin S1 directly to my Chalice Audio 'Grail' SET mono blocks.My question i s where should the Max Volume % be set to..?..I have the Volume Control and Leedh Processing Volume set to 'ON'..
 
Re: Leedh Processing Volume free upgrade

calloway said:
Peter..so the 'Max Volume %' in the Lumin 's app should be set all the way to the left...or '30' on my app..but not all the way over to the right at 100...?Volume control - On...Leedh Processing volume -ON...I take my Lumin S1 directly to my Chalice Audio 'Grail' SET mono blocks.My question i s where should the Max Volume % be set to..?..I have the Volume Control and Leedh Processing Volume set to 'ON'..
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This is meant for speaker protection.
Actual volume = Main volume circle * Max Volume %. If your main volume is 70, max volume is 80%, then actual volume = 70 * 80% = 56.

One way to determine Max Volume % is this. Choose a track which is the least loud, lower the main volume, set the Max Volume % to 100, gradually turn up the main volume until you think that's the loudest you'd ever need. Hypothetically if you find that actual volume 56 is all you need, then perhaps set Max Volume % to 60.
 
Re: Leedh Processing Volume free upgrade

Showroom Dummies said:
Still haven't got round to testing this.
Is there anyone with a passive preamp that has tested this?
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(Excluding dealer members here) You probably have the best passive preamp in this Lumin subforum. Please test it and tell us.
 
From a Lumin U1 MINI + RME ADI-2 DAC/preamp user: LUMIN - Audiophile Network Music Player - Page 105 - Networking, Networked Audio, and Streaming - Audiophile Style
for the Leedh implementation on my Lumin U1 Mini connected to my preamp via USB: it is slightly audibly better sounding to my ears when using Leedh processing and setting the DAC/pre-amp to a unity gain setting, versus turning volume control off on the U1m and using the digital volume control of the DAC/pre-amp.
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Peter, I’m wondering, since the U1 and U1 Mini don’t have DAC chips, before the addition of Leedh Processing Volume, how was Volume Control=On being implemented for the USB output? DSP via the FPGA I presume, but was that DSP similar to how Leedh is done now or are the algorithms very different?

For the Lumin products with DACs (e.g., T2, X1, etc.) I assume the old volume control was via the DAC chip’s proprietary internal volume control, but the new Leedh processing is via the FPGA. Is that correct? What about the digital outputs on those players; how was volume control being done for digital out of the T2 for example? Is the old/original digital-out volume control implementation for the T2 the same as for the U1/U1 Mini?

Regarding connecting U1 to an external DAC like the RME ADI-2 where additional DSP is likely being accomplished, wouldn’t it be best to turn volume control off on the U1 (regardless of the Leedh setting) so that all the “bits” are there for the DAC’s DSP to work with?

Thanks,
M1k3
 
1. The algorithms are very different.
2. Different outputs on different models have different implementations to maximize the SQ. For T2, the analog, USB and BNC outputs go through different paths in the hardware, to achieve the best results we actually have different implementations of Leedh Processing Volume on the T2 (and on X1). Across different models but for the same types of outputs, the implementation is usually similar.
3. This is where theory needs to be confirmed by experiments. Experimentally it was shown the Leedh Processing Volume is superior to the standard digital volume in the DAC. I'm not sure about "additional DSP is likely being accomplished", the presence of some DSP features do not necessarily imply most users make use of them. But if DSP is really used, I think it is even more important to find the result experimentally, as this becomes an issue of less degradation of volume control but leaving less bits for the DSP to work with vs leaving more bits for DSP to work with even knowing the DSP volume control has moredegradation.
 
From a Lumin D2 user with Bel Canto Ref 1000 monoblocks feeding Magnepan 3.7s: Leedh Processing - Perfect Digital Volume Control? - Feature Requests - Roon Labs Community
Referring to the title “Perfect Digital Volume Control?” I would have to reply with a resounding “YES!”
As it is these days - I had quite some time available for tinkering with my system and so I activated Leedh on my Lumin D2 (with LPS) and took the pre-amp (Pass XP-10) out of the chain.
I did not really expect much from the change (especially after a few hickups in the beginning, which were entirely my own fault), but what can I say …?
I was totally blown away by the difference in sound!
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I have not played with it extensively (Lumin U1 via USB to EMM Labs DAC2X to my Modwright LS36.5DM preamp) but did notice that with it engaged, the EMM Labs DAC no longer lights up to indicate a DSD file is playing (the DAC has lights for 44.1 and 48kHz and when a DSD file is played it lights them both up, when a hi-rez file of multiples of either sampling rate is played, only that LED is lit and with Leedh engaged only the 44.1 light is on, which would be indicative of CD quality or a multiple of 44.1).
 
For digital output, volume control requires conversion of DSD to PCM, since digital volume cannot be applied to DSD.
 
wklie said:
For digital output, volume control requires conversion of DSD to PCM, since digital volume cannot be applied to DSD.
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Is there a particular PCM sampling rate DSD gets converted to? The DAC lights up at 44.1kHz which could indicate 44.1kHz or a multiple of it (e.g. if I play a 24/352 file it would light up the same as a CD quality file). My old DAC would show sampling rates of up to 192kHz.
 
wklie said:
Yes, it avoids conversion for analog output.
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I've also noticed that my MQA DAC does not properly recognize MQA music files with LEEDH processing active using the U1 Mini. Once I turn off all volume control, it properly recognizes the MQA stream and decodes the file.

Does the T2 allow you to keep LEEDH active and properly decode MQA files?
 
Any kind of digital volume or DSP will destroy MQA integrity, therefore your external MQA DAC will no longer see it as MQA. The "Authenticated" part of Master Quality Authenticated ensures the bit stream is not changed. Digital volume changes the bits.

For Lumin with internal DAC, since the volume is applied after MQA decoding, full MQA decoding to T2 analog output is unharmed by digital volume.
 
wklie said:
Any kind of digital volume or DSP will destroy MQA integrity, therefore your external MQA DAC will no longer see it as MQA. The "Authenticated" part of Master Quality Authenticated ensures the bit stream is not changed. Digital volume changes the bits.

For Lumin with internal DAC, since the volume is applied after MQA decoding, full MQA decoding to T2 analog output is unharmed by digital volume.
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I'm using a Topping D90 MQA DAC with the Lumin U1 Mini and get loud pops anytime it switches from DSD to PCM (volume control bypassed on both Lumin and D90). Very concerned about the health of my speakers as a result. Any idea why this is happening? The D90 uses the XMOS XU216 USB interface. I've read the XU216 may be the culprit.

Thinking of moving to the T2. Are you aware of any issues with pops when there is a change of format or sampling rate? I want to ensure I avoid the same issue with pops if I make the move.
 
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