microRendu Measurements Thread

[Moderated]

Since you have stated that you feel the prospect of a digital I/O device improving sound quality is very very low… Can you please expound on and give us your view on software and it how it may or may not impact sound quality in this context also. Oh and BTW; since MR is an audio device designed for listening to music, have you bothered listening to it?

thank you

[quote=“Bob_Sherman, post:135, topic:8219”]
R is an audio device designed for listening to music
[/quote]it’s a microcomputer with ethernet input and USB output and some audio software loaded…as much an audio device as the next PC, except it claims to be better suited to audio application than other micro computing devices.

Correct. Architecturally it is a simple device. Its SOC (core CPU and system logic) is from freescale. It has a dual core ARM processor running at 1 Ghz! It has GPU for 3D operations, hardware video decoding, support for various copy protection systems, etc., etc. In short, it is a very high-end device for the functions that it is designed for. Single unit pricing for its CPU is $30! If I were to design something for audio, I would have opted for a much lower speed processor that would use less power, run cooler and have less potential for radiated signals.

I am puzzled why they thought they should use such a high powered platform given the target market and size of this device.

[Moderated]

If others are interested, I will write an article on ASR forum for it.

Well, I was going to do some of that testing but alas, as I reported earlier on ASR forum, the microRendu no longer recognizes my DACs. :frowning: I have tried everything and it just refuses to recognize the DAC.

Did you get yours and how does it sound to you?

Hi Tom. That is great to hear. And thank you very much. The forum is still new (started a couple of months ago) but I hope to keep growing it with technical articles and measurements.

Sorry, I assume everyone knows my history of testing of other products from John Swenson. He has produced another project, a USB device called the Regen. As here, I found through my measurements that it degraded performance when used as intended. And again like this round, usage of my lab supply cleaned up the problem. I then met with him and his sales person Alex and rocky mountain audio fest (RMAF). We spent a good hour together and during that time I realized that he doesn’t have any audio measurement tools. And that his day job is a digital designer in unrelated field so he did not have access to such equipment at work either.

Perhaps he now has such measurements and will post the results. Until then, my assumption is that no one would would measure this combo would recommend it for sale to audiophiles. A 30 db increase in mains noise and harmonics is no small matter.

Good USB DACs, even bus powered ones like the iFi DAC that I used, have post regulators that clean up the USB power. There is no reason or excuse for power supply noise to bleed into their output. And this is a low end DAC. I expect high-end audiophile USB DACs to be totally insensitive to such things. Please see the measurements of my Berkeley Alpha USB bridge driving my DAC here: http://www.audiosciencereview.com/forum/index.php?threads/high-performance-pc-server-interfaces-async-usb.8/

Those measurements were with my then Sony laptop driving the DAC. We see no evidence of the kind of noise that is present in microRendu. Performance is superb across the board. See this graph: http://www.audiosciencereview.com/forum/index.php?attachments/mark-levinson-502-hdmi-input-vs-berkeley-vs-audiophilleo-png.7/

I would immediately return any high-end USB DAC that is not immune to source/computer USB vagaries, noise, etc.

Indeed by using a low-end DAC here, I am giving these devices every chance to show that they can reduce noise. Yet what we see at best is no difference and at worse, degradation.

The marketing of audio tweaks has done a disservice to consumers by creating such worries and then selling products to fix them. They may be right but where are the measurements? Noise is trivial to measure. Why not demonstrate such facts? Where are all the measurements of laptops having noise injected into high-end DACs? I have not seen such.

What is your DAC? I would start with its measurements through its USB port. If it excellent, then I would not worry whatsoever about using it direct.

You should only use these devices if you need to put them far away from your computer server. Otherwise, you are buying yourself less reliability and extra expense.

This thread is for discussion about measurements relating to the microRendu. I have separated the discussion out from the microRendu General thread. I have moderated posts and parts of posts where they do not comply with the Forum guidelines or consist of discussion of such posts. I have indicated [Moderated] where I have moderated a part of a post, leaving the part that relates to audio discussion.

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Auralic Vega

I eventually intend to put my BRIX server further away from my stereo than it is now in order to isolate fan noise (comes on using closed form in HQP, which I like).

Also in addition to the DAC’s voltage regulation/supply, a lot of newer DACs employ XMOS chips or the like. These chips when properly deployed, completely isolate the power and noise on USB side of the DAC from the actual DAC and analogue circuitry on the output side, making the computer on the other end of the USB cable largely irrelevant.

Room Treatments?

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Absolutely!

Agreed. No kit upgrades and audiophoolery will get you as large an upgrade as a properly treated room or at least some DRC.

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Kit excluding speakers themselves of course. No amount of room treatment was going to make my Focals sound like my new Wilsons. :grin:

Yeah. My listening room is my great room with a tv, DVR, etc. in it, so the room isn’t the best. Better speakers make the most improvement.

[quote=“Amir_Majidimehr, post:42, topic:11761, full:true”]

Sorry, I assume everyone knows my history of testing of other products from John Swenson. He has produced another project, a USB device called the Regen. As here, I found through my measurements that it degraded performance when used as intended. And again like this round, usage of my lab supply cleaned up the problem. I then met with him and his sales person Alex and rocky mountain audio fest (RMAF). We spent a good hour together and during that time I realized that he doesn’t have any audio measurement tools. And that his day job is a digital designer in unrelated field so he did not have access to such equipment at work either.

Perhaps he now has such measurements and will post the results. Until then, my assumption is that no one would would measure this combo would recommend it for sale to audiophiles. A 30 db increase in mains noise and harmonics is no small matter.

Good USB DACs, even bus powered ones like the iFi DAC that I used, have post regulators that clean up the USB power. There is no reason or excuse for power supply noise to bleed into their output. And this is a low end DAC. I expect high-end audiophile USB DACs to be totally insensitive to such things. Please see the measurements of my Berkeley Alpha USB bridge driving my DAC here:

Those measurements were with my then Sony laptop driving the DAC. We see no evidence of the kind of noise that is present in microRendu. Performance is superb across the board. See this graph:

I would immediately return any high-end USB DAC that is not immune to source/computer USB vagaries, noise, etc.

Indeed by using a low-end DAC here, I am giving these devices every chance to show that they can reduce noise. Yet what we see at best is no difference and at worse, degradation.

The marketing of audio tweaks has done a disservice to consumers by creating such worries and then selling products to fix them. They may be right but where are the measurements? Noise is trivial to measure. Why not demonstrate such facts? Where are all the measurements of laptops having noise injected into high-end DACs? I have not seen such.

What is your DAC? I would start with its measurements through its USB port. If it excellent, then I would not worry whatsoever about using it direct.

You should only use these devices if you need to put them far away from your computer server. Otherwise, you are buying yourself less reliability and extra expense.
[/quote]Sorry to have to ask this again but… You have only use this testing methodology it seems to test two devices designed by John Swenson. You have given your opinion which we all have read, but we have no idea if this testing is valid. You have been asked more than once to please test some other devices, plug in a different DAC for example to see if the results are the same. If your testing cannot differentiate between DAC’s, that means all DAC’s must sound the same. It is important to know if your testing methodology is even valid.

Interesting comments here from Superdad (Alex Crespi of Uptone) re-counting John Swenson’s thoughts on these ASR measurements. I hope JS wades in somewhere officially and blows @Amir_Majidimehr methodology out the water, not least because there does seem to be some hidden agenda going on here. First the Regen and now the mR, both products designed by Swenson which I am absolutely loving in my system. My ears tell me that there is very little ‘noise’ deep down in what I am hearing on either of these products, just as the designer intended.

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I have provided little opinion. I have documented a test procedure with known and top class instrumentation used by major audio magazines such as Stereophile. As with their reviews, manufacturer and others are welcome to conduct their own tests and present their data in conflict. I read yesterday that John has reviewed my results so that part is done. Hopefully they present their measurement data to confirm or dispute what I have done and we go from there. Until then, this is the only objective data that you can touch and smell about this product.

There is a difference between people who make constructive comments and those who try to create dust in the discussion to protect the manufacturer. I am not here to go and chase everything you throw at the dart board. I have a long list of other projects to do. The data as it stands has disputed the manufacturer’s statements of what this product does (i.e. reduce noise whereas it increased it here). And confirmed that otherwise, it has not had ability to improve the DAC. Testing other DACs with other outcomes does not change what has already been presented.

You want more measurements and are on the side of consumers? Go and challenge the manufacturer to do that.

This is all moot at this point any way as my device is no longer functional. The have asked me to return it and that is what I will do. Until I get a fix, this is the end of this project.

I looked up the measurements JA did in Stereophile and it was superb. The amount of distortion products while using USB was incredibly low. And this was JA testing it with some old Mac computer. http://www.stereophile.com/content/auralic-vega-da-processor-measurements#MptLv3uJUEZi102K.97

I would not use any tweaks, etc. to improve on its performance. Unless of course you need to extend its reach through Ethernet as you mention. There I would look for the cheapest, most reliable and manageable option you can find. If microRendu is it, use it with a linear power supply.

Congrats for buying such a high performance DAC! :slight_smile:

I have responded to those comments on ASR forum.

I am disappointed in the tone and style of Alex there. I had actually offered my own time and resources to them to fix the Regen. After such cordial interactions, it was difficult to read him question my competence. But I will live :slight_smile: As always, I welcome manufacturer data that corrects any mistakes in my work. That is not a concern.

Anyway, I am going to leave this discussion as the management seems to be blocking some of the content in my posts which I respect. Thank you for the opportunity to comment. Take care you all.

By wades in, do you mean measurements to disprove Amir? Anything less with just be "blow"ing in the wind. I find it rather amusing that some owners are on defence and accusing persons of hidden agendas. It’s your money, you feel it’s an improvement over what you had before enjoy your kit. Sheesh!

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