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About mitchco

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  1. A partial list here: https://audiophilestyle.com/ca/reviews/nad-viso-hp50-with-roomfeel-headphone-review-r720/#subjective
  2. Great question! I don't have an answer as I liked both speakers a great deal and could easily live with both. One part of me believes the magic Bruno has achieved as the most neutral speaker out there. i.e. no colour at all - truly neutral. The other part of me is trying to reconcile if I like that sound or not. I think I do. It reminds me of Rythmik subs and their Direct Servo technology. Very understated and dry sounding as their distortion measurements confirm on https://www.data-bass.com versus other subs. but that is what I have in my system today. What can I say 🙂
  3. Dryer sound - less distortion is my best guess, given the electronics quote. That's what is fundamentally different compared to the 8c. "According to Putzeys, distortion of loudspeaker drivers can be optimized by varying the amplifier’s output resistance for different frequency ranges. This requires an amplifier that is specifically tuned to the parameters of the loudspeaker driver. An amplifier like this can never be a commercial good-for-all piece of equipment. They have to be tailor made, and this is what was done for the Kii Three." From Audioxpress's excellent review
  4. Nothing in the REW files as I am talking about the direct sound. I can only attribute the difference to the overall electronic design and perhaps, "unique to the implementation used in the Kii THREE is a combined voltage/current control loop that goes beyond merely a better amp – it actively improves the distortion performance of the drive units which contributes significantly to the extreme resolution of the speaker." Don't know exactly what that means 🙂, but one would need an anechoic chamber and associated mic, preamp, ADC that has low enough distortion to be able to measure properly to confirm.
  5. Here is the frequency response of both the Kii THREE and the D&D 8c overlaid as measured in my room. Both were tuned to produce a downward tilting response from 20 Hz to -10 dB at 20 kHz as per Harman's research. This was achieved using the onboard controls only. The 8c is a bit smoother in the bottom end due to the additional PEQ's that the THREE does not have, but it in a double blind comparison, I doubt I could pick the two apart from a tonal perspective. As others have mentioned, the THREE sounds "dryer" than the 8c is about the only way I can describe any difference. The 8c's treble required next to no adjustment to match Harman's research. However, the THREE out of the box required a -4 dB shelf at 3 kHz to match. So, out of the box, without any adjustments, the Kii's may sound overly bright. Of course, both speakers fr can be made ruler flat using room eq like Audiolense or Acourate. Personally, I would just use partial correction from 500 Hz and below, as both have a wonderfully smooth response above 500 Hz. The cardioid design of both speakers really make a difference in the low end response where you don't get the crazy 25 dB of total up and down swing due to room modes, like in my room. So to get that smooth low end response is a real testament on how well both speakers deal with room modes with their cardioid design and on-board boundary controls. Given it's cardioid design and pretty smooth low end response, it will be interesting to see if any kind of FIR based room eq makes it's way into these products. The limiting factor is the on-board computers with the DSP chips that limit the number of FIR filter taps it takes to smooth out the low frequencies over time. Most hardware based DSP is limited to around 6000 taps per channel, whereas on a PC with Audiolense or Acourate one can use 65,536 or even 131,072 taps per channel for total low end control over time.
  6. See this article on how to import mic calibration file. Use a 48 kHz sample rate instead of the 96 kHz I used in the article. https://audiophilestyle.com/ca/ca-academy/acourate-digital-room-and-loudspeaker-correction-software-walkthrough/
  7. You mean something like this: And zooming from 1 kHz on up with the Kii on one channel and D&D on the other: As I have demonstrated in this article using binaural recordings, it is amazing how frequency response accounts for almost everything (except directivity differences) where two different loudspeakers with similar/same frequency responses can sound almost the same or indistinguishable...
  8. Great review by @Kal Rubinson and measurements by @John_Atkinson at Stereophile for the 8c! Excellent to see a good correlation of both subjective listening and objective measurements when reading both articles. This speaks to the robustness of @mensink design and engineering acumen that results in a neutral sounding package regardless of set up and room. Leading the pack IMO. One item of note Kal is your comment, "The treble was smooth and open but somewhat under-stated, Read more at https://www.stereophile.com/content/dutch-dutch-8c-active-loudspeaker-system-page-2#ju5uiVG81a5oqZ2E.99 Sure, not only agree with you, but prefer that as most other consumer speakers sound overly bright to my ears. Typically measuring +5 dB hotter starting anywhere from 2 to 4 kHz all the way up to 20 kHz as compared to the wonderfully neutral sounding 8c. Overly bright to my ears is what I hear going on at audio shows. I don't know if loudspeaker designers are not using the latest design and engineering best practices ... Or not understanding the science that a neutral sounding speaker will measure flat in an anechoic chamber, but an in-room frequency response measurement will have downward/sloping tilt of ~20 Hz to -10 dB at 20 kHz, which is perceived as neutral sounding to our ears. By this measure, and as the science shows peoples preference, it turns out that most speakers are designed to be too bright sounding. But D&D "gets it" 🙂 Thoughts?
  9. @crenca when I first got the HP50's, I could not wear them for more than 2 minutes because of the clamping force - I have a big noggin and ears. So I grabbed the headband just above the ears cups on both sides and tried to split them apart. Lo and behold, there is a pivot point just above the ear cups on the headband that "gave way" on both sides of the headphone. Initially, I thought I busted them as there was quite the crack, but seems to be a pivot point. Now I can wear them for hours without any issue as the clamping force is "normal". Sure the headphones sit half on and half off the ear, but once the clamping force has been adjusted, it is much easier to position the cups on the ear to give the best fit/sound possible. For sure the ergos are not the best, but a really good neutral sounding headphone for the money. I would love to upgrade to something a lot more comfortable, but regardless of price, their sound quality is hard to beat for neutrality.
  10. Nice review Josh! Good to see measurements too! I am still enjoying my HP50's, definitely not the most comfortable ergonomic design, but I do like the sound. Keep up the good writings! Cheers, Mitch
  11. Hi @Em2016 I do feel the Golds are bright sounding, at least to my ears, from a neutral frequency balance preference. But still sound smooth as I don't hear any high frequency distortion. Nothing new on the list other than I upgraded my dual Rythmik L12 subs to F18's and very happy with the result: https://www.avsforum.com/forum/113-subwoofers-bass-transducers/1214550-official-rythmik-audio-subwoofer-thread-1223.html#post57390652
  12. @Em2016 Here I overlaid the Kii THREE's, D&D 8c's and the Phantom Gold's left and right distortion measurements. As noted, my equilateral triangle is about 9ft and each of these were calibrated for reference level playback (i.e. 83 dB SPL): As can be seen, all three speakers are well behaved from a distortion perspective at reference listening level. I would not take the absolute distortion numbers as gospel as these were not performed at 2.83v @ 1 meter. I also limited the the low frequency bandwidth to 500 Hz as below that I believe at that distance the room comes into play more than the speakers (could be true for all frequencies and the distortion is just the noise floor of my room). Also, my measurement mic is not the best for taking distortion measurements... To understand why the distortion plot stops at 10 kHz: https://www.roomeqwizard.com/help/help_en-GB/html/graph_distortion.html But the point is from a relative comparison perspective, all three speakers are super smooth and none of them sounded distorted in any way to my ears. Like I say, I don't recall at all, for any of these speakers sounding distorted in the top octave. Wrt the soundstage measurement deviation from linearity at 90 dB, I could no speculate what or why that is. The Gold is a DSP speaker, so there could be a limiter in the amp circuit and have nothing to do with the tweeter for all we know. Cheers, Mitch
  13. Hi @Em2016 yah, I don't remember any high frequency distortion when listening or measured. I am away from my main computer until Sunday, but will see if I have some measurements comparing the Kii Three and D&D 8c with the Phantom Golds and post up some distortion charts. Cheers, Mitch
  14. Hi @Em2016 yes it would be very easy to use digital room eq to tone down the bass and treble. But I was hoping the speaker would have some onboard capability like the D&D 8c or the Kii Three to contour the tone. Given that this is a DSP type speaker already, it seems like (and still is) an oversight not to have simple tone contouring available to the user, who may not have digital eq or a measurement system...
  15. Toole and Olive spent a great deal of R&D effort over years that included controlled subjective listening tests. I wrote a summary of that here, which Sean Olive peer reviewed before it was published: https://audiophilestyle.com/ca/reviews/nad-viso-hp50-with-roomfeel-headphone-review-r720/#science My preference is for a flat, but tilted target response from 20 Hz to -10 dB @ 20 kHz as measured in-room at the listening position. According to Harman’s research, this objectively measured flat, but tilted frequency response, (i.e. spectral balance), is subjectively perceived by our ears as a flat or neutral or accurate response. The deets are in the link above. Another good read is Toole's open access AES paper on The Measurement and Calibration of Sound Reproducing Systems: http://www.aes.org/e-lib/browse.cfm?elib=17839 Check out Fig. 14. Subjectively preferred steady-state room curve targets in a typical domestic listening room and the "trained listeners" preference. Depending on the speakers directivity and how damp/reflective ones room is, there maybe some fine tuning of how much more or less tilt is required by a couple of dB. This is easily accomplished by moving up or down the -10 dB @ 20 kHz point in the target response and then give it a listen and compare. I have tried many targets over the years, including the ones @semente linked above from the ASR forum. The straight line, but tilted target response sounds the most neutral to my ears. I think Toole and Olive's R&D in this area is the most credible, and really the only body of work I know of that uses subjective listening tests to correlate their objective measurements. They have repeated these tests over and over again, with different speakers and listening subjects and end up with virtually the same results each time. The first link above points to the body of work at the end of the article section in presentations, which points to over a dozen AES papers on the subject area. Good luck and have fun!
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