Articles, Reviews and Measurements of Audio Products

Review and Measurements of Budget ($20) DACs

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This is the measurements and review of two budget DACs, the FiiO Taishan and Signstek Mini USB DAC:
1. FiiO Taishan


My reference for comparison is the iFi iDAC2 which retails for $349 or 17 times more money.

FiiO does not have USB input. To feed it audio I used the Coax output of iFi iDAC2. SIGNSTEK does have USB input so I used that as a complete system. It also has Coax input but I could not get it to work. Nor could I find a manual for it.....
Sonore MicroRendu Hardware Teardown and Review
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Some of you have seen my previous measurements of Sonore MicroRendu ( If you have not, this is a device that "remotes" your DAC by letting you use Ethernet networking to connect to a USB DAC. Outside of this functionality, many buy this for the presumed improvement in audio fidelity. My measurements did not show such improvement however. And to this date, no one has produced any that show otherwise.

For a part 2 of this project I thought I open the unit and show what is inside. The unit is inside of a small, cheezy aluminum case. Put aside any expectation of high-end fit and finish here. A couple of screws opens the one end and lets the guts slide out. What is inside is a main "I/O" board on which there is a daughter card that holds the main CPU that runs all the software.

Dealing with the CPU part, it is a typical all-in-one SoC (System on a Chip) on a PC...
Measurements of Sonore microRendu Streamer
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NOTE: this is an updated review of microRendu. Measurements were updated to use bitperfect path and max volume.


One of the latest trends in digital audio is to use a "streamer" device. This is something that sits between your music server on the home network, with then direct connection to the DAC. A lot of such devices have been built with Windows and Linux operating system on top of PC computer hardware. Sonore's microRendu is different in that it is built as an embedded, black box implementation.

This thread is about its measurements and not a full review. But briefly, this is a tiny device the size of a set of playing cards:


Both the packaging and aluminum enclosure scream "budget" equipment. So if you are getting this device as audiophile bling to impress your friends, this is not it.

The unit as mentioned, is a "bridge." It sits on the Ethernet network at one end and USB connection...

Entreq "signal grounding" Preliminary Measurements

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Here are measurements of the Entreq "signal grounding" box. If you don't know what that means, you are not alone :). It is a type of device where you connect it to the ground or negative terminal of your audio signals and it is supposed to improve the fidelity of the system. I was kindly given a loan unit of Entreq Olympus Minimus for this testing by the company founder, "PO."

The box arrived a few weeks ago but have been too busy to test it until now. From the outside, it is a nicely made wooden box with a single terminal out back:


The box is very heavy so clearly filled with something substantial. I was not allowed to open the box so my evaluation is limited to measuring it.

I had thought of measuring a lot of things but once I got to it, the reality set in. The box has only one wire going to it, not two. That is, there is no return path for any electrical signal. Think of trying to test a...

Amir's Music Server Build Thread

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Over the last few months I have had a number of requests to document my music server build. I finally got around to collecting and organizing my pictures and references.

There are a number of such efforts such as CA's "CAP" series of music server specs. I have read through them and much of what they do there doesn't make any sense to me and bring a ton of complexity. As an example is using a server-class motherboard, Windows Server OS which is expensive and very difficult to manage for ordinary users, expensive linear power supplies, etc.

The approach of then minimizing the tasks on the OS true third-party tools also doesn't make sense to me. From noise and jitter point of view, you want a chaotic/random activity. Removing all but a few system processes means both of these components can be become more correlated, predictable and hence potentially audible.

My goal in building my own server was much more down to earth:

1. 100% quiet. No fans. No spinning parts. Acoustic...
Are Our Preferences Different in Audio?
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It seems intuitive that we would all have different tastes in sound reproduction. After all, there are thousands of different brands and models of speakers each with a different sound. Surely that is due to different people liking different sounds. Another fact that bolsters this intuition is that there is no reference for audio. So in that sense, there is no metric of accuracy either meaning it is a free for all, allowing anyone to pick any sound as being what they prefer.

Well, everything I just said is wrong! Turns out we are remarkably alike in what we prefer subjectively. We seem to have an internal compass that points to good sound and that when we only use that compass, we are able to determine what is proper and what is not. Dr. Toole in his book, Sound Reproduction, Loudspeakers and Rooms puts this most eloquently:

"Descriptors like pleasantness and preference must therefore be considered
as ranking in importance with accuracy and...

Judging Individual High Resolution Audio Perception Capabilities

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Really good talk/work by Bob Schulein, presented at Audio Engineering Society on how to determine an individual's dynamic range, and bandwidth that they can hear. There is a link to the files to be downloaded at the end. And summary results of the AES Chicago chapter.

Bob is a slow speaker so I watched it with no problem at 2x speed :). Click on the gear and select the playback speed there.

Acoustic Measurements: Understanding Time and Frequency

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Modern computing power has put in our hands incredibly powerful measurement tools. Prime example is Room EQ Wizard (REW), a free program which is an amazing toolbox of acoustic measurements. Alas, while computing power may be free enabling us to run such analysis that used to cost a lot of money in dedicated hardware, the fundamentals of what the tool measures must still be understood. Otherwise, it is exceedingly easy to arrive at the wrong data and worse yet, wrong conclusions about the science.

The purpose of this article is to demonstrate a key element: the relationship between time and frequency resolution. This is an underlying signal processing concept that is core to functionality of everything from audio and video to compression to how we measure room acoustics. Alas, while the concept is rather simple, it is not intuitive nor is it talked about much outside of the circle of industry researchers and professionals. Simply put, time and frequency resolution are enemies...

Review: ProStudioMasters High-res Music Distribution Service

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This is a review of the PROSTUDIOMASTERS, a distributor of high-resolution music content:

I first ran into this site when I was at Sony’s web site looking at their high-res music page. A link for content took me to ProStudioMasters. What I found was a delightful experience. Modern, interactive and fast user interface that easily leaves all of their competitors behind. When I am interacting with other sites, they feel like what music distribution looked before iTunes revolution. Primitive web sites, lousy payment methods, and all around ancient experience. What a breath of fresh air it was to land on ProStudioMasters and not see most of these issues. Let me dig in to show you why.

User Interface
Here it is:


Modern, “web 2.0” interface that is a delight to look at, and highlights the album art nicely.

Notice how under each album you see the...
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