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About mitchco

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  1. 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!
  2. Vintage Armaco AR20A circa 50s or 60s... Beckman DM27xl circa 90 Used in building amps, preamps, headphone amps, checking continuity, resistance, bias adjust, etc.
  3. Hi @malarz OK cool. You can control the sweep output level via Acourate. You can also insert a passive preamp(s) between the DAC and amps or use line attenuators to the mid and tweeter amps. You can also passively attenuate the drivers with pads (or L-Pad's) but not the best approach, but if no other way, then...
  4. HI @malarz I am not sure I understand the context... Assuming you have 6 DAC channels for a stereo 3- way active setup and outputting the DAC channels directly to the input of 6 channels of amplification? If so, does the DAC analog outputs have level control?s Or do your amplifiers have an input level controls? If so, then the idea is to trim the input level of each amplifier so that the logsweep produces a reasonably flat response or tilting downwards response as the frequency increases over the full range. Usually you run the woofer amp channel wide open as the woofer has the least sensitivity, then the midrange and then the tweeter needs the most level attenuation to be in line with the woofer and midrange levels... I may have misunderstood your question...?
  5. Hi @blue2 Thanks for the kind words. I see no-one has got back to you on this. Purchasing a calibrated measurement mic and REW is excellent acoustic measurement software to get you going, is a great idea. I don't know how you are going to get around the 2 sounds devices as seen by the computer though... I don't have any experience with Audirvana or HQPlayer,... However, getting the analog split off your preamp to the subs should work. With REW you will be able to assess your setup and then make a plan from there... Of course, I recommend Audiolense as the fastest way to integrate the subs with some room correction...
  6. Hi @ShawnC Sorry, I have no experience with either. You might have better luck with your q's on AVSForum, as the LS50W is popular there... Here is one thread: https://www.avsforum.com/forum/113-subwoofers-bass-transducers/2805681-kef-ls50-wireless-sub.html Kind regards, Mitch
  7. @rando Thanks! My conclusion sums it up... Really, I am looking for the most neutral sounding headphone out there. According to Tyll, who has measured over 1000 headphones (wow!!), and referencing Harman's scientific study around neutral sounding headphones, plus my own measurements and subjective listening, these are it! I recently upgraded my binaural mic preamp, as mentioned in one of my earlier comments, and recorded a tune with these headphones and then compared to the original recording. I am really impressed how close the recorded sound compares to the original track. Don't know what to say, I am still impressed on how neutral these sound and listening to them right now
  8. @Kvalsvoll I think you are taking my article too literally 🙂 I said similar frequency response, not exact. As already caveated in the article, several times, the LS50's were placed in a room null whereas the JBL's were not. This accounts for the difference in the 50 to 60 Hz dip. Again, as noted in the article, had I moved the LS50's to the exact same spot as the JBL's, would have resolved this issue and perhaps a few others. Also noted in the article, the science shows our ears/brain are not too sensitive to narrow band dips in frequency response below Schroeder. The JBL has a near infinite baffle whereas the LS50 does not. This will cause a different Speaker Boundary Interference Response (SBIR) above 100 Hz to around 400 Hz (directivity related as the polar response will be different for both speakers in this frequency range, aside from the fact that the LS50's were not in the same physical position as the JBL's...). The JBL's "constant directivity" comes into play at around 400 Hz: Where as the LS50's does not. The rest of the differences on up in the audio band are due to the directivity differences between the two speakers. As Floyd Toole and Sean Olive have often said, one cannot eq directvity. So both the measurement and correction software are "blind" to directivity, as we are measuring and correcting the sound power in the room (i.e. steady state response). The point of the article is to show that two speakers eq'd "similarly not exact" sound remarkably close, yet the big difference being how much room sound is let into the recording by the wide directivity differences between these two specific speakers that represent the near opposite ends of the directivity index scale. The intent is to have folks listen to binaural recordings to hear the audible difference and determine what one's preference is with respect to how much room sound one likes mixed in with the direct sound. It is nothing more than that. Enjoy the music!
  9. Hello @Kvalsvoll I see you just joined CA and this is your first post. Welcome! Thanks for your feedback. The only fair comparison is the LS50 plus sub vs JBL with sub as they have a similar frequency response, but very different directivity index. The LS50 standalone was to let people listen to what it sounds like without a sub. Checking on the specs, The little speaker is rated at 106 dB SPL max output and 2nd & 3rd harmonics (90dB, 1m) <0.4% 175Hz-20kHz with 85dB (2.83V/1m) sensitivity. I don't think the speaker was overloaded. at 83 dB SPL at the LP. I follow these levelling best practices using pro gear. 83 dB SPL I do not find too loud and has the right balance of bass to treble. For overly compressed material I drop the level down to 77 dB SPL. Kind regards, Mitch
  10. Hi Ram @Ragera Thanks.. I have not reviewed the Genelec 8531, so can't comment. Ram, the main issue is that few speaker manufacturers publish their directivity specs. I don't see any listed for the XTZ for example. You can get some ideas from Soundstage measurements from the NRC: https://www.soundstage.com/index.php?option=com_content&amp;view=article&amp;id=16 While the LS50's are a steal for a grand, they are geared more towards near and mid-field listening and not best suited for your application given size of room and listening distance. Unless of course your preference is for more room sound, but you indicated you wanted to reduce early reflections... Tough to recommend due to lack of speaker manufacturer's directivity data. As a rule of thumb, which you already know, is speakers with waveguides tend to have a higher directivity index than domes... This is why I use JBL, not only for the waveguide, but they publish their directivity specs. Without the data, it is difficult to recommend... Regards, Mitch
  11. Thanks @isleofskye The 4722's ($2K US a pair) are bit narrower directivity than the 4429 or 4365. If you biamp the 4722's like I have, then you require digital or electronic XO. A multi-channel DAC, four amps, protection capacitors for the compression drivers. I upgraded the compression drivers on my 4722's based on a really long thread on AVSForum where one of the members tried several different compression drivers. Some DIY along with DSP is required to make these sound their best. Whereas, the 4429 or 4365's are ready to go as is. The JBL M2's are the closest to the 4722's, as they use similar tech, but with upgraded components in the M2. If I had the dough at the time, I would have gone with the M2's. But if you have the space, like huge dynamic speakers and willing to diy a bit, the 4722's are a good choice, if you can stand how fugly they are 🙂
  12. The Grace Design m101 is really nice kit! Gets great reviews. It was a toss up between the Grace and the ART, and I just emptied my pockets on a sub upgrade, and went with the ART. I am happy to hear it is working well for you. Good to know. Thanks. Mitch
  13. Allan @folzag, thanks for taking the time to listen to the binaural recordings and your response. It would seem our listening preferences are similar 🙂 I am still amazed at how much directivity difference there is between these two speakers, which is on the binaural recordings. I feel confident that the differences are predominately directivity related. My room has enough treatment to make the decay time (RT60) not only smooth across frequency range, but within industry guidelines for my size room. It does measure towards the livelier side of the spec... Thanks again, Mitch
  14. Happy New Year Dennis! Thanks for your kind words. Yes, I tried the up close and did not sound natural and was bested by the binaural recording. I got around to purchasing this mic pre and after a shootout, it still comes up on top against the more expensive ones. It's a discrete Class A design with 40 dB of gain before the tube stage. The binaural mics I use are high output and won't need the tube stage. Thanks for the approaches. Good idea on one speaker in one channel and the other in the other channel... Cheers! Mitch
  15. Hi @Tin When the KEF's were playing (even with subs) I put my ear up to the JBL cones and port and could not hear anything. If there was something, then it is too low in level and being masked by the SPL of the KEF's to my ears.
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