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mitchco

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  1. Thanks, but I also included music samples that one can compare to the original track and to another set of phones. Did you listen to those? No doubt audio is subjective, however, when it comes to measurements, some are pretty straight forward and indeed account for (very) audible differences between sound reproducers. For "accurate sound reproduction" if that is your goal means then the sound reproducer, whether headphones or speakers, should accurately track the input so the output is the same or as reasonably close to it as possible. So when it comes to frequency response, which accounts for a large part of what we hear and judge sound reproducers on, a smooth frequency response is a basic requirement. Unfortunately, both measured and in the recordings, the LCD-4z does not meet this basic requirement in the top end. It is not smooth. While one's preference may differ, the LCD-4z's are not accurate sound reproducers. Wrt speakers, Floyd Toole and Sean Olive with many years of research has shown that a speaker that measures well on and off axis in an anechoic environment will indeed subjectively sound good in a normal listening environment. In fact, their results show a high correlation (86%) between their objective measurements and controlled subjective listening tests with many test participants. Their predictive model in estimating the in-room frequency response based on "spinorama" anechoic measurements is so good it is included in the CTA 2034 A Standard Method for Measurement In Home Loudspeakers that you can download for free. Look at Fig 11 on page 37 that shows the predicted in-room response based on anechoic measurements compared to the actual measured in-room frequency response - they are identical. Olive did the same work with headphones with hundreds of participates over several years, which shows most everyone has similar preferences when it comes to what makes for a good sounding headphone. Hence the Harman Target Curve. Those are linked in my objective review. While I agree that audio is subjective, there is considerable research into correlating objective measurements with subjective listener preferences, to the point where industry standards are developed from this research. Let's not throw out the baby with the bathwater and perhaps raise the bar a little to what constitutes good sound, which can be objectively measured. Here is yet another data point using Harman's test rig on the LCD-4 (not Z) but has the same issues my measurements show with non smooth high frequency response. The next measurement is the calculated score based on deviation from Harman Target Curve using their predictive model. Score is 65%. It suffers from having 5-6 dB less bass and treble.. which you can see by looking at the RED error target curve and with the non smooth high frequency response.
  2. Sorry @Facel I cannot disclose at this time, but the review will be up soon...
  3. @Facel Thanks for asking. No, I have not as I am still adding to the DSP software product portfolio I intend to cover in the next edition. Even though the DSP concepts and most of the procedures in the current book apply to virtually all digital loudspeaker and room correction products, I am getting into the implementation details of each DSP product. I am also adding a chapter on integrating subwoofer(s) as this is a problematic area, especially if one wants to time align subs with mains. There has been new research into target frequency responses correlating to listener preferences, and a new industry standard on measuring loudspeakers and predicting in room responses that are being added to the book. Right now, a new and interesting DSP software product is being added and there will be a review of it on AS shortly. Sorry, I don't have an ETA on when the next edition with be available, but I am working on it. Kind regards, Mitch
  4. Agree with mansr. I have been doing it for years into a 3 way active system with no loud mishaps. In my case I use JRiver's internal volume control which also has volume protection. Not sure if foobar2000 has that or if it even really matters. As mansr noted, just need to be a bit careful is all.
  5. Hi @omid Very nice! If you are getting a good step and frequency response with REW, then everything is fine. Does the Xonar card come with an ASIO driver? One thing you could try if you have not already is to check the response of the signal path sans speakers and mic. But if you are getting a good step and frequency response out of the speakers, then it is likely there are no issues at all. Wrt the attenuation of the digital filter, in JRiver's convolution you could click on normalize filter volume which would bring some gain back. Is there a similar setting in Roon? Another way is to add a digital gain stage. In JRiver, one could use the eq plugin just to add gain, but with no eq. There are VST plugins that can do this as well. I have used Blue Cat's Gain Suite to do this. Just have to watch for any clipping. Seems like you have it all sorted. I think Bernt is working on some of the multichannel issues in AL V6, so this may also allow the use of Wasapi or ASIO. But it seems to me there is nothing to worry about. Cheers, Mitch
  6. @detlev24 Thanks for your kind words and comments! Given I like large, high efficiency loudspeakers with horns, I like your reference choice 🙂 Re: Generally, I would like all manufacturers to be more transparent and more accurate with the data they release! Totally agreed! Especially since there is a standard for loudspeakers measurements called, "CTA-2034-A Standard Method of Measurement for In-Home Loudspeakers". The standard is publicly available and free to everyone. "This standard describes an improved method for measuring and reporting the performance of a loudspeaker in a manner that should help consumers better understand the performance of the loudspeaker and convey a reasonably good representation of how it may sound in a room based on its off-axis response and how this response affects the consumer’s experience." It is well worth the read and embodies the accumulation of work by Floyd Toole, Sean Olive and others in a industry acknowledged standard. It offers a standard report format that consumers should demand to see for any given speaker purchase. Sometimes referred to as "spinorama" report. The only place I know that informally catalogs similar reports is: https://speakerdata2034.blogspot.com But given the science of designing and measuring loudspeakers, that has been proven over and over again, even since Floyd's spinorama paper from 2002, it seems very few speaker manufacturers have cottoned onto this. I hope consumers put more demand on loudspeaker manufacturers to produce these reports, especially the new CTA 2034 A standard (from 2015 to be updated by the end of this year) format where it is clear to see the speakers on and off axis response and especially the predicted in-room frequency response. Cheers!
  7. Hi @omid Welcome aboard! And thanks! Perhaps you can briefly describe your measurement mic, gear and signal path for taking measurements? I doubt you are missing anything, but always good to have a 2nd pair of eyes have a look. Having said that, if you are happy with the SQ, then stick with what works. But lets have look anyway 🙂
  8. In this objective review of the Audeze LCD-4z headphones, I measure the frequency response and provide binaural recordings of the headphones so that folks can download and listen to music samples. The music samples are compared to the original track so one can hear, relatively speaking, any differences between the source and headphone reproduction. In addition, there is a comparison to the NAD Viso HP50 headphones both from a frequency response and binaural recording perspective. The binaural music recording switches back and forth every 10 seconds between the two headphones, so one can evaluate tonal differences between the two. Preamble A few points to put this review into context. Unlike most headphone measurement rigs that use a dummy head, I am using my own noggin and ears as the dummy head (still a dummy head says my wife). This way I can adjust the fit and feel of the headphones to sound just right to my ears. Many headphone measurement rigs require a “compensation curve” to interpret the raw headphone measurements. Tyll does a good job of explaining that in the link above. However, in this particular case, I have found a set of in-ear measurement mic’s that seem to not require (much of) a compensation curve, up to 10 kHz anyway. More on that point later. Just like loudspeakers, there are subjective listening tests correlating to objective measurements to indicate that there is a “target curve” for headphones that correlates to what sounds neutral or preferred or accurate. Sometimes referred to as the Harman target curve. Tyll, in the link above, discusses it and I wrote a summary, “The Science of Preferred Frequency Response for Headphones and Loudspeakers” peer reviewed by Sean Olive. There is an educational presentation by Sean and team on, “The Perception and Measurement of Headphone Sound Quality: Do Listeners Agree on What Makes A Headphone Sound Good?” It is interesting to read about the controlled subjective listening tests, objective measurements and conclusions. Since then, the subjective listening tests have been repeated several times, with hundreds of participants, arriving at the same objective results and encapsulated in a more recent 132 page presentation. Regardless of headphone compensation curve, I am using the NAD Viso HP50 headphones as a comparison point with the LCD-4z’s. The reason why HP50 is because they sound and measure the most neutral compared to a reasonably large sample size of headphones. From the link above, Tyll’s comment about the HP50’s (and Focal Spirit Professional), “These two headphones are among the most neutral I've heard, and they do match the Harman target response quite well relative to other headphones I've measured.” At the time Tyll has measured and reviewed some 200 headphones. Having measured and reviewed the HP50 myself, I achieved similar measurement results and agree with Tyll’s subjective statements, quite a neutral response, albeit down in level in the top octave. Using my measurement setup, whatever the frequency response curve measures out for the HP50 can be considered, relatively speaking, neutral or a point of reference for comparison. Then by measuring the LCD-4z, we can compare to “neutral”. This will correlate with the binaural recordings as well. Meaning, with the binaural comparisons of the Audeze LCD-4z to the source track and to the NAD HP50 headphones (that measure and sound neutral), we can characterize the tonal response of the LCD 4z’s relative to an ideal or neutral reference. On a technical note, the Audeze LCD-4z headphones have a rated impedance of 15 ohms. This means many sources can drive these headphones to satisfying levels without the need for a separate headphone amplifier. However, with this low of an impedance, one needs to be careful that the source device driving the headphones should have, as a rule of thumb, an output impedance at least 1/8th the impedance of the headphones. So 1/8th of 15 ohms, is less than 2 ohms. Therefore, the output impedance of the device used to drive these headphones should be less than 2 ohms. My Lynx Hilo headphone’s output impedance measures about 0.08 ohms, so no problems. Here is a link to several headphone devices output impedance that one can compare. At the end of the article I include an appendix on the calibration and verification of the test gear that I used to measure frequency response and make the binaural recordings. In a nutshell, the test equipment has flat frequency and phase response with low distortion. I.e. a transparent recording chain. With the preamble out of the way, let’s move on to the objective measurements. Objective Measurements If you don’t want to look at graphs and would rather listen to the binaural recordings, click here. Here is my methodology to reduce variation in getting a good headphone seal and consistent frequency response measurements. I took ten measures or five stereo pairs, and for each measurement, I adjusted the binaural mics and the headphones to give the best and most consistent frequency response. Here is the left and right channel frequency response for one pair of measurements using REW: As one can see, an incredibly flat frequency response from 20 Hz to 1.6 kHz, with a -3 to -4 dB dip between 1.6 kHz and 4.1 kHz. Then a +5 to +8 dB peak at 5.3 kHz. From there, a -20 dB dip at 7.8 kHz and then a +16 to +18 dB peak at 9.9 kHz. Then another -20 dB dip at 14 kHz. Getting a good seal with these headphones is no problem, but a bit of a bumpy ride in the treble. Now some of that is due to timbral issues with head related transfer function (HRTF) and that it is my head. It is also related to binaural recording techniques whether using the blocked ear method or microphones at the ear drums. Further, getting the binaural mics into one’s ears in the same place each time has variability, as does the fit and positon of the headphones. In the case above, even variability at the top end between the left and right channels due to the right mic’s position. It isn’t easy trying to reduce these variables to record realistic headphone measurements that are repeatable. But close enough to be the same trend in tonal response to match, which is what we are after. One can also compare to other measurements, as we will with the NAD Viso HP50 and correlate the differences, not only in the measurements, but in the binaural recordings as well. Let’s look at a distortion measurement. I would not put too much emphasis on the absolute distortion levels as the test was performed at regular listening level, not to a measurement spec. Also, I have no idea how much distortion is being contributed by the microphones as there is no distortion spec for them. What we are interested in is the overall spectral shape of the distortion versus frequency to get an idea of where there might be some potentially audible issues. Rising distortion in the low end is typical of any headphone or loudspeaker for that matter, often in large numbers, but reasonably low for the LCD-4z: There is a rise in distortion, relatively speaking, from 3.5 kHz to 8.5 kHz. For those wondering why the distortion measures only goes up to half the sample rate can read the REW help. Let’s bring in the NAD HP50’s so that we can make a measurement comparison. I matched the sound pressure level for both headphones by adjusting volume using pink noise as the source through REW so that they matched in level. This was both for the measurements and binaural recordings. I followed the same procedure as mentioned at the top of the objective measurements. HP50 left and right channels – no smoothing: Here we can see an extended response down to below 20 Hz and mostly flat out to 1 kHz with a bit of dip from 1 kHz to 3.5 kHz and the then a rise and only after 10 kHz we see a roll off with some peaking and dipping. Note it is much smoother in the treble than the LCD-4z relative to the magnitude of the peaks and dips. The one thing to notice is that I could not get the best seal on the right ear cup and shows as a channel imbalance in the low end. Don’t really notice it when listening to music. The HP50’s have small ear cups and for my large ears, with glasses and long hair, make it next to impossible to get a good seal. They did at the beginning, but that was due to the brain crushing clamping force applied until I nearly broke the darn things stretching them out. Again, a little bit of right channel imbalance at the top as a measurement artifact due to mic positioning. But comparing to my previous measurements of the HP50, I can verify consistency and repeatability: The red and blue traces are from this review and the green and gold traces are from my previous review of the HP50’s from 1 ½ years ago. As we can see in the previous review, aside from the small low end seal differences, the left and right channels track closely to about 10 kHz. This is why I know that the blue curve in this review is with the right mic not quite positioned correctly. But the left earphone from this review tracks very well with both left and right channels from the previous measurements. As can be seen, I have a little work to do on getting both mics in the same place for left and right measurement consistency. A distortion plot: Pretty smooth with rising distortion in the low end, which our ears are insensitive to, a narrow spike at 1.93 kHz and some rising distortion between 4 kHz and 6 kHz with the right earphone a little higher than the left. Now let’s look at some comparisons so we can make predications on what we think we are going to hear in the binaural recordings. Here I have overlaid the LCD-4z and the HP50’s frequency response – both channels, no smoothing: Both headphones, from a tonal perspective are very close from 20 Hz to 700 Hz, with the HP50’s having a bit more output in that range. The HP50’s are up to -3 dB down from 1 to 1.5 kHz and then it is a bit of a mess to try and sort out after that. To make it easier, I have overlaid the individual left and right frequency responses for comparison. First the left side: As previously mentioned with the HP50 (green trace) having a bit more low and mid frequency output, both have a pretty smooth response up to 6.5 kHz. We see the LCD-4z (blue trace) have a -3 dB drop from 1.5 kHz to 4.5 kHz relative to the HP50’s. There is a -12 dB drop at 7 kHz relative to the HP50’s. Conversely, we see about a +10 dB spike at 9.3 kHz for the LCD-4z relative to the HP50. At the very top end, we see that the LCD-4z has +22 dB more output that 18.3 kHz than the HP50’s. Looking at the right earphone: Good tonal match out to 6.3 kHz. Relative to the HP50’s there is about -10 dB drop in the LCD-4z at 7.6 kHz. At 10 kHz, the LCD-4z have about +10 dB more output relative to the HP50’s at 11.6 kHz and the LCD-4z’s have about +16 dB more output than the HP50’s at 17.8 kHz. Note these graphs are not smoothed. Meaning they are full resolution measurements, but it is commonly acknowledged that our ears don’t hear that narrow bandwidth of frequency resolution. Our ears hear about 1/6 to 1/12 octave bandwidth. So if I apply 1/6 octave smoothing, we can get a better handle on the tonal differences that we expect to hear relative to the two headsets as compared to each other and to the original source music track. Rather than repeating the same graphs above with the smoothing, let’s just look at the left channel between the two headphones. I feel this best represents each headphones sonic signature from a measurement perspective: The HP50 (green trace) have about 4 dB more output in the low frequencies and lowers mids than the LCD-4 from 20 Hz to 750 Hz. Relative to the HP50, the LCD-4z has up to 2 dB more output from 800 Hz to 1.5 kHz. The LCD-4z’s have about -3 to -5 dB less level from 1.5 kHz to 4 kHz as compared to the HP50’s. LCD-4z are -7 dB down at 7.4 kHz relative to the HP50. LCD-4z +9 dB at 9 kHz. LCD-4z +8 dB at 15.4 kHz LCD-4z +21 dB at 18.7 kHz. Comparatively speaking, I expect the HP50’s to have a bit more bass and lower mid output than the LCD-4z’s, both exhibiting a nice smooth response (LCD-4z ruler flat!) with extension to below 20 Hz. Might not be much of an audible difference in the 800 Hz to 1.5 kHz range, but could make the voice on the HP50’s not stand out as much in the midrange. The LCD-4z’s will likely sound recessed in the 1.5 kHz to 4 kHz range, which is also the range our hearing is the most sensitive. So not as bright sounding in the upper mids as compared to the HP50’s. That plus the LCD-4z with the peaks and valleys in the treble response, and the LCD-4z’s having (much) more high frequency output than the HP50’s past 13 kHz will be the most audible differences, I predict. Distortion plot of both left channels: The HP50’s have a bit more distortion in the low frequencies and the LCD-4z more distortion in the 4 kHz to 11 kHz range. Seems to be tied more to the magnitude response level differences... I am not convinced at what level our ears can hear THD as they are frequency dependent. It also requires calibration with a set of mics that have known distortion specs, which these binaural mics do not. So how much distortion is from the mics versus how much from the headphones? And how much is really audible? Not sure if this is providing value as our ears seem to be (far) more sensitive to frequency response variations than anything else. Want to hear it for yourself? Try ABX Testing and Distortion. Let’s listen to see if these frequency response differences are audible in the binaural recordings. Subjective Listening using Binaural Recordings OK here is where the fun begins. I recorded a snippet from Tracey Chapman’s Fast Car. It is a familiar recording with good bass and dynamic range with her voice mixed up in level so it stands out and makes it easy to hear any tonal imbalances. Also pay attention to the “s” in her voice as it can range from dull sounding to overly sibilant. I am using a portion of the song on the basis of fair use for the purpose of evaluation and research. I am not doing this for financial gain. Please delete these music samples once you are done with the evaluation. I level matched the binaural recording to the original track in my DAW (Mixcraft) and then using the DAW’s automation, synchronize the two stereo tracks and switch back and forth every ten seconds so you are getting the benefit of instant switching between the source music track and the binaural recorded track. Looks like this in Mixcraft: There are some “left in” edits when the tracks switch. These can be used as an audible cue to focus in on the new sound to assess the differences before you get used to it as we quickly adapt. I picked a random spot, just before Tracy sings and then a couple of choruses. We start off with the original track for ten seconds and then switch to the binaural track of the Audeze LCD-4z, then back to the original, switching back and forth every ten seconds until the end of the music selection. Tracy Chapman Fast Car Audeze LCD-4z (WAV File - 33.1 MB) (ZIP File - 29.9 MB) To my ears, the bass and mids sound pretty close together, but the upper midrange and treble sound different to my ears. The tonal response of the LCD-4z sound like their measured frequency response where some frequencies are missing in Tracey’s voice, and other frequencies are too much, giving it a distinctive tone and a little too bright sounding overall in the top octave. Overly sibilant sounding as compared to the source is what I hear. While this may be some folks preference, not that there is anything wrong with that, it does deviate from a neutral response like the ruler flat bass and mids that the LCD 4z’s do have. There is some context here as well. The headphones are recorded using my ears with a certain HRTF and is going to have “some” impact. But as you listen, when it is a match, like in the bass and mids, the source and the binaural recording sound amazingly similar. I would love to hear your feedback on what you hear. Are you hearing similar to what I am hearing or different? Now let’s take a listen to the source track and compare with the NAD Viso HP50. Again, starts with the source track and then in ten seconds switches to the HP50, then ten seconds later, back to the source, switching back and forth every ten seconds to the end of the music selection: Tracy Chapman Fast Car NAD HP50 (WAV File - 32.6 MB) (ZIP File - 29.3 MB) To my ears, again the bass and mids sound very similar to the source. Also, Tracy’s voice sounds similar to the source from a tonal perspective. It does not sound “filtered.” However, as seen in the frequency response measurement, the top octave after 10 kHz drops off fairly quickly as the attack on the guitar strings, the hi-hat/cymbals and Tracy’s “s” all sound down in level (i.e. dull) compared to the source track. A little shelving eq or treble control boost above 10 kHz would bring the level back up. Then it would be more difficult to tell the two apart. There are balance issues between left and right channels that one can hear in this binaural recoding (and the LCD-4z too) as the center image shifts a bit when switching. This is due to the binaural mics not sitting perfectly in each ear canal. What are you hearing? Finally, a direct comparison of the LCD-4z to the HP50’s: Tracy Chapman Fast Car LCD4z and HP50 (WAV File - 32.9 MB) (ZIP File - 29.5 MB) Regardless if listening over headphones (preferred) or speakers, and regardless of individual HRTF’s, it is a direct comparison where one can hear the “relative” differences. The two big differences that stand out for me is that Tracy’s voice sounds close to as it should with the HP50’s whereas listening to the LCD-4z’s sounds like the upper midrange of the frequency range is missing in her voice and then accentuated too much in the treble (listen to the “s’s”). The treble response in the HP50 is rolled off, but easy to fix with a basic high frequency (shelving) tone control. Not so easy with the LCD-4z as it is going to require parametric eq to deal with the ups and downs in treble frequency response. What are you hearing as the differences between the two headsets? Conclusion The Audeze LCD-4z have an incredible flat frequency response in the bass, with good extension below 20 Hz and flat midrange response up to 1.5 kHz. This is evidenced by the measurements and correlated with the binaural recording comparing to the source track. I mean it sounds and measured perfectly flat with excellent matching channel balance. Also matches the Harman target curve for a neutral frequency response pretty well up to 1.5 kHz. From there, we get into deviations from neutral with a little lower level output in the 2 to 4 kHz range, which is right in our human ears most sensitive range. Then we get into some peaks and dips in the upper midrange and treble. Not only measured, but also heard on the binaural recordings, both comparing to the original source track and the NAD HP50’s. Finally, overall a little too much high frequency energy past 13 kHz, both measured and heard. Of course there are complicating factors related to measuring headphones and making binaural recordings using a person’s (or dummy) ears (mics fitting properly and repeatedly is one example). While it may not represent the absolute truth, from a comparative perspective, it appears to be quite accurate as there is not only good correlation between the measurements, but also comparing to the source music track. The direct comparison differences between the two headphones should hold true, regardless of one’s own HRTF, headphone or speaker brand while listening to the binaural recording. As a side note, I believe this binaural recording technique is sensitive enough and enough resolution that if there is an audible difference when directly comparing two devices, using music as the test signal, then the recording will pick it up and accurately represent it on playback. One can always eq the LCD-4z’s towards a neutral response if desired. The data to implement parametric eq (PEQ) is contained in this review where inverse filters for the peaks and dips could be created for both channels. Bring up the response in the 1.5 kHz to 4 kHz range and then bring the overall treble response down to neutral (or taste) and. I would use the 1/6th octave smoothing graphs as the guide for PEQ. Or if you really want to fully optimize the response, one could get a pair of binaural mics, a mic preamp and use DSP software like Audiolense or Acourate to accurately tailor the response to be neutral, and matched to your own HRTF. Or even try the Impulcifer which is like an open source version of the Smyth Realiser. I did try Audeze Reveal, which has an eq preset for the LCD-4z, as a plugin in JRiver. To my ears, it was a subtle difference and did not tonally change or reduce the treble response. I did not get a chance to see how customizable Reveal is. Finally, make sure the device you are using to drive the LCD-4z follows the 1/8th rule for impedance matching. For a 15 ohm headset, the driving device needs to have less than 2 ohms output impedance. I hope you are enjoying the music! Appendix: Calibration and Verification of Measurement Equipment The purpose of this section is to list the test equipment I used and verification measurements performed to ensure a transparent signal path so as not to influence the headphone measurements or binaural recordings of the headphones. Test sample rate is 48 kHz and all digital and analog levels on the Lynx Hilo are set to 0 dB unless otherwise noted. Sound Professionals MS-TFB-2 Binaural Microphone I have tried many binaural microphones and dummy head set ups over the years. I find the Sound Professionals MS-TFB-2 to be a unique set of binaural mics as when put in-ear, they have an incredibly flat frequency response. No other binaural mics I have tried have this characteristic. Mine were ordered with the XLR ends and phantom power converter so they can be used with a mic preamp that has phantom power. You can read the rest of the specs from the link above. Contacting the supplier who indicates the frequency response was measured in an anechoic chamber using the standard for measuring microphones. While I can’t verify the frequency response, I can say over the years using this mic set for a number of binaural recordings of music and nature events plus audio gear, I am reasonably confident of the spec. A shout out to Chris at The Sound Professionals for answering my many questions in a timely manner. ART PRO MPA II Microphone Preamplifier The ART PRO MPA II is a stereo microphone tube preamplifier that in a shoot-out out ranked several top name brands. Using REW, I routed the digital test signal through the Lynx Hilo DAC analog output and input to the mic preamp with the mic preamp’s output feeding into the Lynx Hilo’s line input ADC and routed back to REW for display. For using a studio pre as a measurement preamp, it did pretty well: -1 dB down at 15 Hz and ruler flat to over 20 kHz using a 48 kHz sample rate. I did run a frequency response test at 192 kHz sample rate and the preamps response was -1 dB down at 50 kHz. Looking at Phase: Flat phase response. Ah, we see the right channel with a higher level of distortion than the left. The good news is that it is linear across the frequency range and at 0.02 percent distortion, very likely inaudible. Btw, that’s with 20 dB of microphone preamp gain applied. What causes the small channel imbalance? It’s just tubes man. I should also point out, these are the same settings (i.e. 20 dB of preamp gain) when making the binaural recordings. The binaural recordings may not be the most quiet, not only due to my environment, but I was quite conservative with headroom. I could have achieved another 10 dB or even 20 dB at best signal to noise ratio, but in the context of “comparative recordings”, this should not cause an audible issue. One should realize that when measuring the mic preamp, I am also measuring the Lynx Hilo AD and DA converters as well, using the balanced XLR connections. Measuring just the Hilo’s analog loopback using balanced connections puts the THD distortion below 0.0005 percent. But since I am using the headphone output, let’s see the Hilo’s headphone amp measurements in an analog loopback test. Lynx Hilo AD DA Converter The Hilo still measures at the top of a long list of pro interfaces for AD/DA linearity and transparency. Here I am measuring the “analog” loopback of the converter through the headphone amp. Meaning I have taken the headphone amplifier unbalanced analog output and fed it back into the Hilo’s analog line input. Again using REW as the measurement software, we see a straight pass through with minimal distortion. Frequency response. Phase response. Distortion. Highest THD was at 30 Hz at 0.0043 percent as per cursor. I could get it to go a bit lower if I moved the connection cable around a bit, so I suspect that this is more related to low frequency noise with an unbalanced connection than distortion. Nonetheless, below our audibility thresholds. Conclusion – the measurement and recording chain verified with a flat frequency and phase response and low distortion. I won’t be including these measurements in future articles, other than sharing a link to these verification measurements. I wrote this book to provide the audio enthusiast with an easy-to-follow step-by-step guide for designing a custom digital filter that corrects the frequency and timing response of your loudspeakers in your listening environment, so that the music arriving at your ears matches as closely as possible to the content on the recording. Accurate Sound Reproduction using DSP. Click on Look Inside to review the table of contents and read the first few chapters for free. Mitch “Mitchco” Barnett. I love music and audio. I grew up with music around me, as my mom was a piano player (swing) and my dad was an audiophile (jazz). My hobby is building speakers, amps, preamps, etc., and I still DIY today. I mixed live sound for a variety of bands, which led to an opportunity to work full-time in a 24-track recording studio. Over 10 years, I recorded, mixed, and sometimes produced over 30 albums, plus numerous audio for video post productions in several recording studios in Western Canada.
  9. Not sure how to answer that as I am following industry guidelines for monitoring music production. A couple of examples are: EBU Tech 3276-1998 Listening conditions for sound programme material and Recommendation ITU-R BS.1116-3 (02/2015) Methods for the subjective assessment of small impairments in audio systems. There are others, but other than the frequency response target and that the monitors are not elevated to accommodate a control room window to the studio, this is how most music is recorded, mixed and mastered, using these guidelines for room setup. The guidelines should be updated based on the work of Sean Olive and Floyd Toole have done showing peoples preference for a more neutral response as per one of my posts above. So if the goal is to reproduce as closely as possible to what was heard in the studio (or venue or concert hall or whatever) by the artists, producers and engineers, I would follow the guidelines. If not, then anything goes 🙂 There is no right or wrong. Every system I have set up or worked on, whether pro or home, I use the equilateral triangle and follow the guidelines. The soundstage always sounds right to me, with a solid phantom center. But that's my preference. I can't listen to speakers that point straight ahead or the triangle is too wide or narrow or the LP is too close or too far from the speakers. In all of those cases, the soundstage does not sound right to me. But again, that's my personal preference to align with industry guidelines. For others, likely different and in some case very different, but I would not argue with anyone's preference if it is different than mine. I don't know the details of your setup to say one way or another, other than to say there is an industry "best practice" that I follow,. It may not be your preference.
  10. No bother at all. I don't know your setup or constraints, but I am a simple guy and follow the same setup as most studios and mastering facilities use to mix and master the music we are listening to. Setup is an equilateral triangle with each speaker toed on in axis to that equilateral triangle. i.e. the left tweeter should be pointing at your left ear, and right tweeter, aiming at right ear, coming to a point just behind ones head. This is how most music is mixed and mastered. Height wise, the tweeter should be at least ear height and ideally mid point between the midrange and the tweeter. No rake as in "exact" mode means the tweeter and midrange (and bass drivers) are time aligned/phase aligned as per the measurement in my review, with 0 degree rake. Now if that is not possible, it is better to have the speakers elevated and pointing down as a compromise. Using a tape measure or laser distance measure, I would ensure exact distances from the rear of the speaker to the front wall and each of the side walls, down to a 1/4 inch tolerance or better if you can. One wants as symmetrical of a setup as possible to maintain the proper stereo image. A 20 kHz wavelength is just over 1/2". It is a pain to do this level of fussing, but it pays off in the image department. Next, adjust boundary and controls to suit neutral or to taste. Neutral is roughly 20 Hz to -10 dB at 20 kHz if 7 to 9 ft away from the speakers. I found the THREE's too bright for my ears out of the box and used a -4 dB shelf at 3 kHz to match the neutral target response. Personally, I would use a measurement microphone and REW to set the boundary and contour controls. Once zeroed in, I would "bracket" on either side of the settings to ensure that is as good as it gets. Finally, and optionally, either use REW's suggested PEQ's or Audiolense or Acourate to tame any further room modes below 500 Hz. The Kii THREE's are one of the most neutral and accurate speakers I have heard. It is worth the effort to got through all of the steps. I get everyone has constraints to their setup, so my steps above are ideally speaking. Hope that helps and you are enjoying the music out of these wonderfully accurate sound reproducers!
  11. Here is one objective test comparing "pro" AD DA converters using a repeatable procedure, that folks can run themselves if they wish: https://www.gearslutz.com/board/showpost.php?p=14093948&postcount=1776 While the Lynx Hilo is on top (it is amazingly transparent!), any one of the converters listed in this thread will work just fine. The simple reality is that LP's typically have 10 to 12 bits of resolution and even the most mint, first time use from top mastering labs like Analogue Productions may make it to 14 bits of resolution (max). Wrt bandwidth. While there may be some output in the 20 to 24 kHz range on an LP and in some rarefied cases higher, the real limitation is the source. Meaning microphones, mixing consoles, effects boxes, tape machines, tape heads, tape electronics, tape itself, compressors/limiters, mastering lab amps, etc, and on it goes. Not to mention most speakers , when measured, don't have significant output beyond 20 kHz anyway. Most studios then and now, still consider 20 Hz to 20 kHz as the standard bandwidth. I would consider 24/192 kHz to already be overkill. 24/96 kHz is more than enough and even 24/48 kHz is likely to be just fine. Source: ex recording/mixing engineer that spent +10,000 hours in the chair. Personally, I would grab one of the higher ranking AD DA converters in the list above plus a copy of Vinyl Studio and start converting and then enjoying the music!
  12. Hi @aps no, I would always recommend a high pass or better yet, a linear phase digital XO between sub(s) and mains. A linear phase XO sums properly both in the frequency and time domain. So yes, with a multi-channel soundcard or DAC, AL or Acourate digital XO would be used to manage low/high pass to subs and Kii's. Similar to what is done in this article: https://audiophilestyle.com/ca/ca-academy/ integrating-subwoofers-with-stereo-mains-using-audiolense-r712/ The trick is to find the best XO point and this is where the room comes into play. In my case linked above, my mains have good output to 40 Hz or a bit below (i.e. the -3 dB point in the room). Using tools like https://amcoustics.com/tools/amroc I have a large room mode, right at 40 Hz. So to offset that, I chose 45 Hz as being inbetween room modes for my XO point. In the case of the Kii's and @TheStupidOne setup, is using additional woofers to supplement the Kii's. Turned out good! There are no hard and fast rules. However, if using a traditional "sub(s)" with the Kii's, I would take Kii's advice (and mine) of finding the -3 dB point in-room of the mains (whatever they are) and cross there.
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