From http://forums.audioreview.com/audio-lab-tweaks-mods-diy/jon-risch-distortion-test-signal-6529.html [Quote Of a supporter drawing Jon out mayby for the last time.... This is just a very small portion of all Jon had to say. I wish not to inflame the science guys at all but to support the cable fans and those disappointed with digital artifacts. I also strongly contend that much presented in this long thread is in support of why the Sony DVPS7000 was such a phenomenal transport, never to have been matched except by later Sony players. Also I thought it appropriate as my KRK project will adhere to Jons bi-wiring advise. Note mods may move this here if need be. https://www.head-fi.org/search/8582304/?q=*&t=post&o=date&c[thread]=876953 ...skwoodwiva] """ J Risch said: 09-13-2004 09:35 AM Reply To Resident Loser Chairman Jon??????? First, for those who have not had access to my AES paper on the Phi Spectral multitone, I have placed a text-only copy here: http://www.geocities.com/jonrisch/PhiSpectral1.htm While the text copy provides sufficient information and data to understand the concept behind the idea, the graphs and measurement results are a huge aid to understanding what is going on, if one is familiar with spectrum analysis results. If anyone is interested in seeing the extensive graphics, then they can e-mail me at email@example.com, and request the PDF of the paper. Be warned the PDF is approx. 3.4 Meg, so it is not recommended for regular phone line connections! If you are in this situation, and would like a copy, e-mail me, and we can work out a snail mail solution. Second, let me say that there have been some folks at the old AR that claimed they read and comprehended my AES paper on the Phi Spectral multitone signals. However, it became clear, that some had either not actually read the paper, or that they had failed completely to comprehend it, based on criticisms and comments they made. This is not surprising, I have found that folks either "get it" and realize what a boon this is to measurement SOTA, or they don't get it, and invariably act as if it is some sort of boondoggle, and totally unnecessary. With that in mind, I will respond to some specific points made here in this thread, referring to them as quotes in brackets. Quote Originally Posted by Resident Loser . Music(as most musicians know) is a series of mathematical relationships...so when it is mentioned that this "new" test is not comprised of "multiples" of what practical application is it?.. I deliberately and specifically use a non-harmonic sequence for the reason given in the paper, to avoid the inevitable cover-up of the distortion products that such a signal would cause. You appear to be postulating that because the test signal does not replicate the harmonic structure of music, that it would somehow not be relevant. This kind of thinking would then invalidate all the other common test signals used, because none of them replicate the harmonic structure of music either. Single continuous sine waves used for HD and THD measurements do not have a harmonic structure, the IM measurements using two tones do not, etc. Most folks familiar with the reasoning behind and the use of the current test signals would be able to address this point, so I will not belabor it here. Suffice it to say, through the use of more than just one or just two pure sine waves, the Phi Spectral multitone is closer to real music in stimulating the DUT with a much more complex signal, one that has a higher crest factor than any of the more traditional tests. Quote Originally Posted by Resident Loser . Is this tone played as though it were a "chord"?...is it a series of arpeggiated tones, which would simply make it the oft-discounted "test tones" It can be many things, but what I proposed and measured in my paper were a more or less continuous tone, consisting of either 6, 10 or 12 pure sine wave tones, at frequency spacings that are not harmonically or common integer fractional related (this latter meaning 1/3 octave spacing, or 1/2, or 1/4, etc.). Quote Originally Posted by Resident Loser .Perhaps, the "squeaky clean" recorder isn't...What protocols were followed to be quite certain the source material itself isn't contaminated in some way? Aside from the fact that I am a professional, and have taken the numerous steps necessary to assure that no such errors occurred, I can say specifically on this particular point: that the test signals were generated in the digital domain, using what was then Cool Edit, these wave files can then be directly analyzed within Cool Edit to see what the spectral content is. In addition to this, the wave files were burned to a CD-R. This CD-R was then played back in a variety of CDP's, and the output of these CDP's was sent ot a spectrum analyzer, and the test signal studied and analyzed. Once a suitably clean CDP was selected, the signal was run through a mixer used to set levels, and thus the mixer was checked for distortion and contamination. Other measurements that were not all electrical, such as the speaker distortion tests, were performed using accepted industry techniques, using well known instruments and tools, such as ACO and Larson Davis, etc. I do want to note that ALL of the forgoing information was stated in my paper. Quote Originally Posted by Resident Loser "so much for all CDPs sound alike"...Who ever said that? It has been said transports read ones and zeros...that error correction and such is fairly identical...after all I think it's SONY and Philips who arrived at the standard and who produce the vast bulk of the transports used...the output is then "tweaked" to provide the specific "sonic signature" each manufacturer thinks they can sell. I think you have a very distorted and simplistic view of how a CDP works, and what is going on internally. The various transports and laser assemblies all have varying abilities to read the discs, some can sail through damage and obscuring materials like fingerprints, and others can stutter and choke on the slightest deviation from perfection. So even the ones and zero's sometimes do not make it out perfectly. Aside form that, once we have the digital data stream recovered from the transport, it has to go several places before it comes out as an analog signal, you make it sound like the transport data is connected directly to the manufacturer's "tone controls". Not quite that simple. The raw disc data has to be digitally filtered, and then this filtered digital signal is passed on to the DAC, which provides the analog output to the output stage. The digital filtering is one of the areas where there is a lot of variations on what amounts to nearly the same textbook/traditional measurement results, but a lot of variation in terms of other parameters. Since the AES paper, I have verified that the digital filter in some CDP's clips on complex signals when they get within 3-6 dB of 0 dBFS. This was verified to be the result of the digital filter, by using a CD-R with various levels of the Phi Spectral test tone, and by monitoring the output stage for clipping levels etc., including injecting suitable levels of analog signals to see at what level the output stage did clip by itself. So my new test signal has already shown results which can not be obtained via the more traditional test signals, even including most of the multitone test signals in use prior to my signal. Jon Risch (now posting as J Risch) J Risch said: 09-13-2004 09:41 AM Reply to markw and Swerd Quote Originally Posted by markw ...wrapped up in scientific sounding mumbo jumob that was essentialy ignored by those in the know. comic relief at the convention perhaps? But, I'm sure the simple minded who want to believe in him will take great pride in his words and be suitibly impressed. Impressed enough to tout this as another of his great breakthroughs. A true victory of idol worship and wishful thinking over reality. This reply addresses comments made by both markw and swerd in this thread. First, it may not be common knowledge, but for the last 12-15 years, the AES has had many more papers submitted than there are time and space for presentation at an AES conference. At the one I presented at, where I gave TWO papers, the ratio of submitted papers to slots available was at least two to one, that is, there were twice as many papers submitted than there were time slots available to present them in. Thus, my paper was pre-selected in order for me to even be able to present it at all. One way of looking at this, is that I had already passed a criterion where my paper was deemed to be in the top 50% of the AES membership, or it never would have been given. Publication in the AES journal has a whole different set of criteria, not all of which are obvious and not all of which are wholly related strictly to merit (or the technical "goodness" or "utility"). It may come as a shock to some (but not those who belong to other professional societies or organizations), that some of the process is unavoidably political, and to some extent, based on who knows whom. It may come as another shock to some, that I am not exactly one of those who has sought to curry favor and provide for my own advance in the ranks of the AES, and have even made some enemies within the ranks of the old school engineering clique. It is not too hard to figure out that given these circumstances, my paper was not rushed to the front of the line, nor was it necessarily considered impartially for ultimate publication. In any case, just because I have not publically published any further work on the signal, does not mean it has withered away. Over the years, I have been contacted by engineers and scientists from all over the world, concerning the details and specific questions about my test signal, and know that at least a some time over the last 5-6 years, that researchers from Denmark, Japan, Germany, Poland, Norway, Hong Kong and Taiwan have used it to investigate various audio components, as well as various companies in the US, including Klipsch, Cerwin-Vega, and several others. My paper has been referenced over a dozen times that I know of, because the authors contacted me at one time or another. These are just the folks that I know about, there are likely to be many others using one form or another of the Phi Spectral signal, and they have not made it public or contacted me. I have come up with new versions of the test signal, and have been working to incorporate some sort of weighting scheme to weightt he order of the distortion product, and display it so as to make it easier to interpret the spectrum analysis results. Jon Risch """