• mitchco

    by Published on 01-24-2017 08:07 PM
    1. Categories:
    2. Speakers
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    In the first of a series of loudspeaker reviews, the Dynaudio Focus 600 XD full range tower is first up. This “all in one” full range, DSP optimized active 3-way floorstander, is a techno tour de force of computer aided design optimizations. In my review of the Vancouver Audio show, there were a handful of advanced loudspeaker designs that use Digital Signal Processing to optimize the performance of the offering. The Dynaudio’s were one of those speakers that I was curious to listen to and measure. In this review, I provide subjective listening impressions and objective measurement results.

    Loudspeakers reviews are difficult to write as it comes down to personal preference, aside that everyone’s listening environments and equipment are different. However, this approach is designed so that my listening experiences and objective measurements results, as compared to industry guidelines, should translate almost 1:1 to virtually anyone’s listening environment. I show an example of this from half way around the world.
    One goal is to characterize each loudspeaker against a set of industry guidelines, and build up a library of subjective listening impressions and objective measurements. The industry guidelines referenced in this article show a high degree of correlation to listening preferences and objective measurements, spanning 40 years of research and development. Covering not only the loudspeakers, but also the listening environment.

    For the acoustic listening environment, as long as one is within the specs as described in the industry guidelines, then the review characterization and measurements should translate to one’s environment with a high degree of confidence. My stereo setup is offset to the left of center, along the long wall, firing across the short width of the room. In addition, not the most favorable room ratio and my room is quite lively. Still, with a little ingenuity, I am able to meet the industry guidelines for early reflections and reverb time and so can you.
    by Published on 07-21-2016 03:30 PM
    1. Categories:
    2. 2016 Vancouver Audio Show
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    Cones, Domes, and MQA

    It has been many years since I have been to an audio show, so I was pretty excited to be invited by Archimago to attend the Vancouver Audio Show. I must say I had a great time! I was very fortunate to be able to sit in the sweet spot for most of the demos, including the MQA demo with the Tidal Sunray G2 loudspeakers and Burmester 909 Mk 5 amp above.

    Rather than detailing equipment specifications and prices, I take the approach of how each exhibit sounded to my ears. As a reference, I compare to a sound reproduction system that has been calibrated for accuracy. My definition of accuracy means the frequency and timing response of the music arriving at my ears matches as closely as possible to the content on the recording. I wrote a book on the subject. ...
    by Published on 12-02-2013 05:31 PM
    1. Categories:
    2. Room Correction
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    In this article, I walk through the steps using Acourate to create a 3-way digital crossover (XO) for tri-amping my speakers. Additionally, using the audio toolbox functions of Acourate, I walk through the steps of time aligning the drivers, linearizing each driver, and performing a final room correction.

    With respect to room correction, I recommend reading, “Acourate Digital Room and Loudspeaker Correction Software Walkthrough” for an introduction to Acourate. The article details the steps of acquiring a calibrated microphone, measuring the system, and designing a baseline room correction to provide the listener with a perceptually flat frequency response at the listening position.

    My goal is to make this guide repeatable so anyone following the same steps should be able to achieve similar results. Using digital XO, time aligning and linearizing the drivers, and correcting the room’s frequency and excess phase response, increases my systems imaging resolution so my speakers *disappear*. ...
    by Published on 06-20-2013 09:43 AM
    1. Categories:
    2. Room Correction

    In this article, I walk through the steps using Acourate to produce a default or baseline correction that is repeatable. By following the same steps, one should be able to achieve a similar baseline correction. This baseline correction is designed to provide the listener with a perceptually flat frequency response from 20 Hz to 20 kHz. Making the measurement and correction process predictable and repeatable is important to achieving a successful sonic result that one would be happy with.

    Dr. Uli Brueggemann’s Acourate ( approx. $400 USD) is a high end audio toolbox with many functions. The Acourate web site provides a good description of the software solution:

    The sound arriving at the listening position is measured and analyzed. The quality of the direct sound is analyzed preferentially within an adjustable time window. In combination with a target function (adjustable by the user according to listening habits and preferences) a correction filter is calculated. The music signal will be corrected by the filter during playback. Thus an optimized sound will arrive at the listening position.

    Low frequencies cause standing waves in any room, also described as room modes. Some frequencies will be boosted, others will be attenuated. The room correction avoids too loud playback levels by attenuating the corresponding frequency range. Weak levels will be boosted carefully to a higher level.

    Acourate applies a psychoacoustic analysis to ensure correction filters fitting to the human ears.
    Furthermore Acourate corrects timing errors of the room and the speakers by a phase correction. The target is to get as close as possible to an ideal step response, the best possible coherence, and similarity of response between the loudspeakers.
    by Published on 04-25-2013 10:51 PM
    1. Categories:
    2. Software

    In this article, I independently adjust the amplitude (with digital eq) and bit-depth of a digital music file to identify at what threshold level I can start detecting a difference in sound quality compared to the original music file. In other words, how far away from bit-perfect can I detect an audible change in SQ. All music files are available for download. As a listening experience, feel free to participate to determine your own audibility threshold level. To correlate the listening tests with measurements, the differencing technique described in JRiver Mac versus JRiver Windows Sound Quality Comparison is being used. ...
    by Published on 03-14-2013 02:00 PM
    1. Categories:
    2. OS X,
    3. Software,
    4. Windows

    I have been listening to JRiver Media Center on Windows for almost two years and have been a happy customer. JRiver on Windows is extensively reviewed by Chris.
    Now that an early release of JRiver is available on the Mac, I thought I would take the opportunity to compare the sound quality between the two JRiver music players.
    Similar to how I compared JRiver to JPlay, I am using the following test methods and tools to compare SQ:

    • Using Audacity (or any digital audio editing software) to digitally record the output from JRiver on both Mac and Windows. Then by editing and lining up the track samples, inverting one of the tracks, and mixing them together, we will see what audio signal is left over (i.e. the difference file) and whether it is subjectively audible.
    • Using Audio DiffMaker, that is purpose built software for audio differencing tests, to analyze the two recordings, which also produces a difference file that can be listened to and subjectively evaluated.
    • Using Foobar’s ABX Comparator to listen to each recorded track and determine which one sounds different or subjectively better.
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