Articles, Reviews and Measurements of Audio Products

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...

Roon Music Player and Library Management Software Review

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Hi everyone. This is my review of Roon media player. It is the highlights of what I find attractive in the software. As some of you know, my team was responsible for building the Windows Media Player which ships in every copy of Windows. Alas that software has been frozen in time for the last decade or so, and does not for a variety of reasons meet the needs of an audiophile or music lover. So with the build of my new server, I decided to go a new route.

I had tried JRiver a couple of years ago and immediately dismissed it. It is a huge piece of software and quite bloated in my view. I know it has immense set of features and I am not giving it a fair review in what I just said :). Having managed the development of another complex player namely Windows Media Player, and seeing how hard it was to keep it reliable and performant, I have learned to heavily appreciate simplicity. I don’t need or want video playback for example. What I need is something that doesn’t...

Yet another look at Jitter: Clock Extraction

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I hope you are not getting tired of jitter talk because I have more info to share :).

One of the common arguments made against jitter mattering is that: "the data is buffered and clock regenerated in the DAC so jitter won't be there." This makes all the sense in the world. Once we capture the data and then push it out at our will, there shouldn't be a problem. Well, there is a problem. A serious one. Buffering and clock regeneration do not deal with jitter by themselves. I have explained this in words many times but this time I am bringing in some specific data to hopefully put this myth to bed (yeh, wishful thinking :) ).

The way a clock is "regenerated" is to have a local oscillator (clock) that we can change its frequency to eventually match and track the incoming digital stream. As you may know, S/PDIF is a serial digital connection with clock and data intermixed. By using this circuit which is called a Phase Locked Loop (or PLL for short), we are...

Inside of an Audio/Video Receiver (AVR)

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This is an article I wrote for Widescreen Review Magazine a few months ago.

Inside Your AVR
Do you know what is inside your electronics? What is a DSP? The output stage? Power supply? FPGA? ASIC? Do these terms have any meaning? I suspect for many of you these are obscure terms. Yet, pick up the brochure for any audio/video product and such buzzwords abound. While it is impossible to convey the true nature of these technologies in an article like this, I think we can become more educated and at least have some high level understanding of what goes on inside your electronics. For this article, I am going to open the top of a premium AVR I purchased back in 2007. At the risk of stating the obvious, you are not going to become a design engineer from reading this one article. But rather, get you started on a journey to know more about what is under the hood and what type of design trade off a manufacturer may make. I hope to do...
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