Thread: 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.

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.

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.

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

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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'..

Originally Posted by calloway

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'..

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.

Originally Posted by Showroom Dummies

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

(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.

Peter...thanks for the perfect explanation....

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!

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.

Originally Posted by wklie

For digital output, volume control requires conversion of DSD to PCM, since digital volume cannot be applied to DSD.

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.

Usually 352.8kHz or 176.4kHz.

From a Lumin D2 user with PS Audio M700: Lumin T2 mid/high distortion "spitting" "splatty" DAC gone bad? - Lumin - Roon Labs Community

I have a D2 connected directly to my M700 thru xlr. Dynamics is better compared to when connected with my preamp took away the coloration too.

Yes, it avoids conversion for analog output.

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.

The XU216 itself is not the culprit, its role is like the CPU in your computer. The firmware running on the XU216 has to be programmed carefully to avoid such pops. As a workaround you may force the U1 MINI to convert DSD to PCM by enabling Volume Control. So the DAC only handles PCM and it won't need to switch between PCM and DSD, thereby avoiding any potential DSD-related pop.

Please make sure you're running the latest firmware for the D90 DAC.

There is no pop sound in T2 when switching between any format.

Disabling the volume control causes the volume to be 100, so it's not what you need. The next best thing to do is to set the Max Volume % to 75.

Originally Posted by asiano

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.

I asked someone to test Lumin USB output to a Topping D90 non-MQA DAC balanced output -> Accuphase balanced pre-out -> Benchmark amp, he reported there is no pop sound switching between PCM tracks and DSD tracks.

I would just like to chime in and say that the Leedh firmware addition is a FANTASTIC add! My entire music collection has been reborn. I cannot fathom going back to adjusting volume through the pre-amp. Tip of the cap to you guys at Lumin for providing this free of charge. So very unique in this day and age. I purchased the A1 not too long after its inception, and am still enjoying it to this day. The Leedh processing is like an A1 on steroids. Nice amount of veil lifting.

Again, Kudos

From a Lumin D2 user on Roon forum:

When Lumin came up with Leedh-processing I tried that and was so impressed with the quality that I actually sold my pre-amp - freeing up some money so that I was able to upgrade to a Lumin’s flagship, the X1.

I think there's hardly better proof of Leedh Processing Volume than selling the pre-amp.
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From a Lumin U1 MINI user on a Hong Kong forum:

I received the U1 Mini and connected with my Ayer QB-9 DSD now. Very happy with the outcome. Even with switching power supply it sounds really good. With LPSU the tone is now very balanced. Good bass, high freq not bright either.

I think Leedh volume control is a real winner. I decided to keep the Lumin and sell my XXXXXXXX N100 due to this. With the volume control, I can bring my integrated amp to "normal" level like 40% (or like 10-11 o'clock position). Without it, I have to turn down the volume to like 25% or less and we all know that's not ideal [...] So every component now perform at their sweet spots.

From a Lumin U1 + Chord Dave user from Roon forum: I dare to say I’m happy - Roon Software - Roon Labs Community

With Leedh in my U1 I am able to put the Dave in DAC Mode, thereby bypassing the preamp controls in Dave and going directly to my amp and utilize volume control in Roon. Although I’m still testing, my first impression it is a slight improvement in sound quality and I really like having the volume control in Roon.

You have the choice of leaving the preamp in the system, just turn the volume way up on your Don Sachs, and use the Lumin app on your I-pad or I-phone for volume level.
I am using my I-pad for Tidal and Qobuz so the volume control is right there also. All in one.
Or Take the preamp out altogether. And just have the Lumin do the volume control.
I prefer leaving the preamp in my system as it greatly adds to the party. YMMV.
Either way I do prefer using the Leedh volume control over my preamp's control.

Just a word of caution that if using the Tidal or Qobuz apps on an iPhone or iPad, volume control is done on the mobile device which then uses AirPlay to any Lumin device.

If using the Tidal or Qobuz features of the Lumin app on an iPhone or iPad, then volume control is done on the Lumin device—AirPlay is not used as the Lumin device retrieves the music data from Tidal or Qobuz directly.

If you want to use the X1 volume control then you either need to use the Lumin app (Android or iOS), or you have to use the Roon app (computer or mobile device).

Originally Posted by NekoAudio

Just a word of caution that if using the Tidal or Qobuz apps on an iPhone or iPad, volume control is done on the mobile device which then uses AirPlay to any Lumin device.

For iPad YouTube AirPlay to Lumin, the volume is done by the Lumin device, using Leedh Processing Volume if enabled. The AirPlay protocol can send a volume attenuation value to the receiver (but latest Lumin firmware rescales this value to a more usable scale). (RAAT also sends a volume number to the endpoint.)

Originally Posted by NekoAudio

Just a word of caution that if using the Tidal or Qobuz apps on an iPhone or iPad, volume control is done on the mobile device which then uses AirPlay to any Lumin device.

I have to take back this statement. I just tried using the Qobuz app on my iPhone and adjusting the iPhone volume while streaming over AirPlay to a Lumin device just adjust the Lumin device volume. But adjusting the volume of the Lumin device directly doesn't automatically reflect back to the iPhone volume setting. So it can get out of sync. This led to my earlier confusion and incorrect statement, which Peter corrected.

Please turn down the Lumin volume, then turn up the amp volume. Then experiment to see what combination of the two device volume settings sound better to you.

Originally Posted by chungjh

I connected Lumin X1 directly to my Pass Labs X250.8 (26 db gain). For most recordings the volume control on the Lumin app is sufficient. However, with Janos Starker cello recordings (Mercury Records), particular his Bach sonatas (on both Tidal and Qobuz), I couldn't get the volume loud enough. I had to insert my preamp to get proper volume. I would like to ask if others also find this to be the case.

Please confirm you're using the XLR input to Pass, and you've set the X1 Analog Output Level to Normal. For your setup, your Max Volume % setting needs to be 100.

What speakers are you using? And room size?

Then your issue is with the difference in the volume level between different mastering engineers. Same issue as with playlists or Internet Radio. And yes going to XLR will get you 6db more gain.

Originally Posted by chungjh

No, I am using RCA. Would this make a difference? Yes, the max volume % is 100%. So, the problem is when the next album comes on, the volume is through the roof.

Please power off your whole system, disconnect RCA, and use XLR only. It should sound better too (after some burn-in if you have never used it).

Some albums have such a low recording level, that they require a little bit of preamp gain. Bill Berry's 'For Duke' is one such album, off the top of my head.