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Computer Audiophile


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About mitchco

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  1. Hi John, as an ex 10 year recording/mixing engineer, DSP aficionado, and software engineer by day, I wonder what is the definition of deblurring or temporal deblurring? In the world of DSP, deblurring is usually associated with digital image restoration that can sharpen an out of focus image for the eyes. The only time I have seen it applied in the audio world is when using digital loudspeaker and room correction DSP. This is where the digital signal of the music file is convolved with a custom digital correction filter, so the music arriving at ones ears matches as closely as possible to the music encoded in the digital media file. There are several articles written about this here on CA. Technically, we are talking 65,536 filters taps which is 2000 more powerful than MQA's 32 taps. Also, digital loudspeaker and room correction DSP corrects the entire signal path (i.e. playback chain) to ones ears, both in the frequency and time domain. As far as I know, currently today, this is the only way to achieve fully accurate sound reproduction where the frequency response is flat along with flat phase response and group delay to ones ears. Note this also corrects a loudspeakers timing response, as some 95% of loudspeakers are not time aligned. What would be the point of MQA deblurring if it can't deblur the loudspeaker? Makes no sense. John, I am a real fan of your measurements and wanted to personally thank you for this, especially your talks on loudspeaker measurements. This is why I am puzzled, and obviously others, as to why you would even entertain such a thing? Kind regards, Mitch
  2. Yes, Arch and I took in the Vancouver Audio Show, listening to MQA files on a super expensive rig, but no AB comparisons. Ironically, there is even a picture of us listening to MQA files in the article linked - LOL! Arch has been over to my place for sushi, beverages and having a fun time listening to my stereo. I can "authenticate" that @Archimago is a real person It is rather disappointing that this is even a thing. How about the science? The objective tests Archimago (and @mansr) performed are repeatable. I have not seen any shred of objective evidence to show anything wrong with Arch's test procedures or conclusions. Let's put it to the audiophile industry at large (how about it @John_Atkinson) and especially MQA to prove Arch's tests and conclusions are wrong. Rather than words, lets see some real science! Because, you know https://xkcd.com/54/
  3. Wrt what is audible or not, I would love to see more of this type of audibility testing in the consumer audio industry: The best I could do is around 12 bits of resolution before auditory masking became too much. The experiment posted is repeatable if anyone would like to try, plus files can be downloaded and listened to. When Archimago and I attended the Vancouver Audio Show to listen to MQA files, we had an expectation that we would be presented with some AB testing, so we could hear the difference, as the system was certainly resolving enough :-) However, there were no comparisons and instead listened to some gobbledegook from the MQA sales rep, then a few nice sounding recordings, but no AB comparisons. Given @Archimago's article, we now know why there are no audibility tests.
  4. @Archimago awesome job as usual man! What blows me away is that it takes music enthusiasts to bring to light not only technical deficiencies, but what effectively amounts to industry collusion. I for one, don't want yet another closed, proprietary file format, regardless of the technical gobbledegook offered by MQA. The software industry I work in has already been through that nonsense 20 years ago and resolved it with the open source initiative. FLAC is a perfectly fine, proven lossless file format and is FREE. As someone that spent 10 years as a recording/mixing engineer, FLAC can absolutely represent the studio master with no loss whatsoever. @Samuel T Cogley re: the consumer is always right - perhaps audio enthusiasts need to take a page out of the gamer enthusiasts playbook who used social media to boycott the sales of Battlefront 2. Seemed to be very effective. If folks want accurate sound reproduction from end to end, so that the music arriving at your ears matches as closely as possible to the content on the recording, there currently is only one way to do that and that is by using DSP for loudspeaker and room correction. This allows one to match the music waveforms arriving at ones ears to be as close as possible to the music waveforms encoded on the digital media. Again, great article Arch. I am hopeful that music enthusiasts can see MQA for what it really is.
  5. I have a pair of Rythmik L12's in a 30 x 16ft room. They are small, designed for music subs, and often paired with Maggies. More than enough in my room, even at concert levels. Sound really tight. Love their direct servo tech. I integrated and time aligned them with my mains using Audiolense. I have an upcoming article on that soon. @TubeLovergood luck with your purchase.
  6. The Best for the Least

    HI Chris, yes a pair of 8c's are on their way. I have not been this excited about a speaker for quite a while! I am impressed with their design. Looking forward to listening and measuring.
  7. Yes, low end in stereo to 630 Hz and biamped with much lower voltage gain amps on the top,, so I don't have to "pad down" the compression drivers. I would have got another Crown, but too much voltage gain for the compression drivers, which rarely need more than 1 watt. More details here:
  8. This amp is a real bargain for it's price: https://www.amazon.com/Crown-XLS1502-Two-channel-x2126-Amplifier/dp/B011X2HTZC/ I run balanced XLR output from a Lynx Hilo directly into the Crown balanced XLR inputs. This amp outputs 525 watts a side into a pair of dual 15" high efficiency drivers at 4 ohms. With the amp's input controls turned wide open, in my quiet room, if I place my ear directly at the voice coil on one of the woofers, I can barely hear the amps noise floor as a faint hiss. This series of amp is also known for a very quiet fan, it it runs at all. I have never heard the fan in nearly a year of daily operation. Amp sounds good too :-) Check out Crown's patented Class-I amplifier technology.
  9. Great work man! Sounds great! I also run a Crown XLS 1502 on a pair of JBL double 15" bass bins in my biamped system. They replaced a Nelson Pass Class A amp when I blew it up (had it since 1991) and I am really impressed with the sound quality. I would never have believed it from a relatively inexpensive Class D amp...
  10. I appreciate your support. While the eBook walks through using Acourate, the DSP principles applied are the same. There are several sections in the eBook that are not tool specific and apply to understanding why we hear what we hear in small room acoustics, acoustic measurement techniques, understanding some parameters of good loudspeaker design (e.g. controlled directivity) and understanding industry guidelines and standards for achieving accurate sound reproduction in critical listening environments. If you click on the Amazon link to my eBook and click on Look Inside, you can peruse the table of contents and read the first few chapters for free. I have plans to update the book on several aspects (e.g. sub integration plus some topics here) and cover more DSP tools, including Audiolense. I don't have an ETA for that yet and is a ways out.
  11. @R1200CL I think @dallasjustice comments earlier cover some of this. For sure, designing custom FIR filters for one's speakers in a room is a huge subject area. My eBook is one of many on designing DSP FIR filters, along with a number of articles here on CA. In principle, they can produce similar results, but there are nuances, like different psychoacoustic filtering, for example. Both are excellent products with state of the art DSP functionality, that can work with virtually any loudspeaker and room configuration. Loudspeakers in rooms can be fully optimised both in the frequency and time domain to your ears.
  12. Hi @vitalii427 Thanks. Subs will be disclosed in the next article...
  13. @cjf I use an older microphone kit from http://www.isemcon.net/ashop/index.php?cPath=2_23_28 that is no longer available. It was a combo calibrated mic and preamp kit and still works well and relatively inexpensive. There is a shootout of measurement mics here: http://www.blouder.com/affordable-measuring-microphones-shootout-part-3/ Also one from Ethan: http://realtraps.com/art_microphones.htm As you can see, most of the measurements mics are similar in performance. Some folks will only use http://earthworksaudio.com/measurement/ using a high quality mic preamp http://earthworksaudio.com/products/preamps/zdt-1021/ Not sure what the gain issue is, but my kit uses a mic preamp and RCA line level outputs with plenty of gain back to the Hilo ADC... In my experience, the most important aspect is that the mic is calibrated and comes with a calibration file. We are talking about fine tuning the perceived frequency response (i.e. tonal balance) arriving at ones ears. We can discern a 1 dB difference in frequency response, so accuracy and precision counts. Happy New Year!
  14. @cjf it looks like @dallasjustice answered most if not all of your questions (thanks Michael!). I have been running with software/digital volume since 2011 using JRiver and have not had any incidents. Make sure Windows Sounds in Playback devices, Sound tab, are turned off, as well as Play Windows Startup sound is disabled. With the PC running, I can reboot the computer without any sound issues. If using JRiver, always good to have volume protection enabled... Michael's time aligned results from using the cascaded subs method and Audiolense are excellent. My results are similar using stereo subs, to be seen in a follow up article in the New Year. Cheers, Mitch
  15. Thanks @bibo01 My understanding from Bernt is the max sampling frequency is 400 kHz. Kind regards, Mitch