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    KEF LS50 (David) Versus JBL 4722 Cinema (Goliath) Speaker Comparison with Binaural Recordings

    image1.pngHere are two extreme opposite loudspeakers when it comes to sensitivity, size, directivity, topology and looks. Does the big speaker sound perceptually larger than the smaller speaker? Do the speakers sound the same if eq’d the same and level matched? Does the LS50 sound perceptually bigger when a subwoofer is added? These are some of the questions I attempt to answer in this article.

     

    While there are objective measurements, I have included binaural recordings comparing the level matched loudspeakers so you can hear over headphones what the differences are. Prepare for an ear opening experience.

    I love big, high efficiency loudspeakers. I feel they sound more “dynamic” than smaller low sensitivity “audiophile” loudspeakers. Is it my biased belief or does it prove out audibly? You be the judge by listening to the binaural recordings.

     

    Finally, consider this article a review of the lovely and talented KEF LS50, a precision engineered loudspeaker designed to sound good in your room. This pair is staying in my room.

     

     

     

     

    KEF LS50

     

    There are many positive reviews about the KEF LS50 mini monitor from various publications like Stereophile and Soundstage. I am not going to repeat what has already been written, but I want to point out a key aspect on why the LS50’s sound so good, as evidenced by listeners and reviewers alike since its introduction in 2012 . KEF has written a white paper on their technology progression through the years called, The Reference. It is a wonderful 29 page read if you have an appreciation for fine engineering design. A key aspect of what makes these speakers sound so good is derived from this example set of frequency responses in this chart:

     

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    “Figure 12 shows a set of frequency responses for an early prototype of Reference 5. The curves shown in this plot are the figures of merit for assessing loudspeakers as suggested by the work of Floyd Toole. The curves are measured at 96 data points per octave without any smoothing. Based on these figures of merit Toole was able to predict real listener preference with a remarkable accuracy.” The last sentence is the key idea I want to bring to your attention and expand on a bit.

     

    The chart above is often referred to as a “spin-o-rama” in which you can read about it here in detail (from 2002!) or if you simply want to know how to read the chart. The science behind this enables the key aspect of, “predict real listener preference.” I have written a summary about this before, “The Science of Preferred Frequency Responses for Headphones and Loudspeakers”, peer reviewed by Dr. Sean Olive.

     

    image3.png I bring this up as I took a science leap of faith based on Floyd’s (and Sean’s) research, which was leveraged and acknowledged by KEF in the Reference whitepaper. I purchased a pair of LS50’s without listening to them. But I already knew from product reviews and measurements, and in particular, Floyd’s predictive model, that the LS50’s will sound neutral in my listening room. As one will hear on the binaural recordings and shown in my in-room measurements, the LS50 is a remarkably neutral sounding loudspeaker.

     

     

     

     

     

     

     

     

    LS50 Objective Measurements:

     

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    First, let’s look at a near field (30cm from driver on-axis) in-room frequency response measurement and compare to the NRC’s anechoic measurement:

     

     

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    Courtesy Soundstage/NRC

     

     

    Remarkably similar. My room is certainly not an NRC anechoic chamber, as can be seen in the room picture above. But I can capture the sonic signature of the LS50 with a 30cm in-room nearfield measurement. Thinking of it another way, it also verifies my acoustic measurement setup and capture is reasonably accurate.

     

    Note the gentle rise starting around 2 kHz. If listening to the LS50’s nearfield on a computer desktop, you may need to dial in a high frequency shelf starting at 2 kHz to reduce the high frequency energy ever so slightly. If I wanted to use these as computer desktop speakers, I would still put them on stands behind the desk and raise them up, and if possible, some distance back from the front wall.

     

    Moving the mic back ~9ft to the listening position:

     

     

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    Now we are seeing the room enter the picture, as I have done a fantastic job of placing the LS50’s directly in a room null at 70 and 80 Hz relative to the listening position. ☺ That’s a 20 dB dip and peak over a narrow frequency range. Yes, my room ratio is not good. As perceived by our ears, a 20 dB difference is 4 times as loud or quiet. However, given how narrow bandwidth the dips are, it is questionable on how much we really (don’t) hear it versus how much we just adapt to dips. According to this research, we are more likely to hear peaks over dips. It has been my experience as well. It seems my ears/brain fill in and/or adapt to the sound with dips in frequency response, but more sensitive to peaks. More research required. 

     

    Take a look at the picture of my room and where the LS50’s are located. Ideally, I would have moved the big JBL’s out of the way, and placed the LS50’s in a known good position, relative to the listening position. I have done this in my previous loudspeaker reviews with no nulls. However, this setup will give us a good audible test of a) can we hear the null? b) can we hear digital room correction doing its job?

     

    Beyond 100 Hz we see a smooth frequency response, with the characteristic downward tilt of a perceptually neutral sounding loudspeaker, as per the Science link above. Let’s see how the LS50 compares to my “reference” JBL 4722:

     

     

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    The LS50 frequency response is overlaid with my JBL 4722 system with dual subs, which uses the preferred in-room measured frequency response, as referenced from Toole’s and Olives research. Meaning, the 4722’s with dual subs have been DSP’d from 12 Hz to 21 kHz ±3 dB to my preferred target frequency response with a slope from 20 Hz to -10 dB at 20 kHz. The KEF LS50 hits that predicted in-room response based on its spinorama figures of merit quite closely. Validating Floyd’s predictive model… again.

     

    It is likely if I moved the LS50’s to the location where the JBL’s are, in an equilateral triangle, then the off axis response may drop those +1 dB bumps between 2 and 3 kHz, 4 to 6 kHz, and 20 kHz down a bit, as evidenced by the Soundstage NRC off axis measurements.

     

    I wrote a soapbox piece on why more loudspeaker designers aren’t using this publicly available Standard that is based on Toole’s research that clearly works for KEF (plus JBL, Revel, and a few others). Most speakers I listen to are too bright, as indicated in my other loudspeaker reviews. Only the Dutch and Dutch 8c came out of the box with nearly identical in-room frequency response matching the preferred target. The KEF LS50 is the 2nd speaker I have measured that matches the preferred in-room target frequency response for a neutral sounding loudspeaker, right out of the box. I would hazard a guess that most folks would enjoy its neutral response. Let’s listen.

     

     

     

     

    LS50 Subjective Listening

     

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    A little preamble before we listen. I used the same binaural recording setup in this article for reviewing a set of neutral sounding headphones. The binaural mic specs and preamp frequency response measurements are there. The headphones measured ±3 dB from 20 Hz to 7 kHz and then rolling off smoothly after that. What goes on beyond 7 kHz is largely due to ones ear and how the mics are placed in the ear. My article linked above shows some of this variability. Point being, the binaural mics are quite flat from 20 Hz to 7 kHz with a smooth roll off.

     

    I wasn’t striving for ultimate recording fidelity, I wanted to have the binaural recording sound good enough, and with high enough resolution, to capture tonal differences between loudspeakers. This comparative objective and subjective analysis is what I want to focus in on. As one will hear in the binaural recordings, the top end “air” (i.e. top octave 10 to 20 kHz) is down a bit in response, as compared to when I listen to the speakers “live”. Just wanted to point out that difference between what I hear live, versus what’s on the binaural recording.

     

    Another psychoacoustic effect is that I hear more of the room sound mixed in the binaural recordings versus when listening live. Floyd Toole’s research has indicated that we have a tendency to “listen through the room” and quickly adapt. Anecdotally, it seems the same for me. When I listen to the speakers live, I don’t hear as much of the room, as I do on the binaural recordings.

     

    However, one interesting aspect to listen for when we get to comparing wide directivity (LS50) versus narrower directivity (4722) speakers, even though the tone quality is similar, you can hear more room sound in the LS50 binaural recording versus the 4722 which presents more direct sound due to the speakers (much) higher directivity index. 

     

     

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    The graphic above shows the measured directivity over frequency for a double 15” and 90 x 50 CD horn, which are the JBL 4722’s. The 15” woofer and 120 x 100 CD are the JBL M2’s and the Domestic cone/dome system is the Revel Salon 2. The KEF LS50 is a cone and dome system and likely similar to the Salon 2 from a directivity perspective.

     

    As we will hear, the directivity index is an important factor on how much direct versus reflected sound one prefers. In the case of this JBL M2 versus Revel Salon 2 shootout, most folks preferred the Salon 2, with the lower directivity, even though both speakers have very smooth and similar frequency responses. This later spawned a thread at diyAudio on The Preference for Direct Radiators.

     

    The audible difference is significant enough that with a little ear training on what to listen for, one can tune into that direct versus diffuse sound and start to hear the difference right away. The other aspect one can hear on the binaural recordings is that the left side of my room is a bit livelier than the right, as I moved the acoustic drum kit that was there, and heavy quilt I put over top of it when critical listening, downstairs. The kit used to sit to the left of the couch, but currently is an open reflective space:

     

     

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    At 83 dB SPL reference level, which is the SPL I took the measurements and the binaural recordings at, while not overly loud, I can definitely feel the sound pressure level on my couch, not only bass frequencies, but lower mids as well. Of course, that feeling does not translate in the binaural recording. 

     

    There is deep bass on the binaural recordings with the subs added, so one might want to check with Tyll’s headphone measurements to see if the headset being used can reproduce down to 20 Hz. I used a pink noise wave file and a calibrated sound level meter to set the reference SPL and subsequently level match the other binaural recordings.

     

    With that in mind, binaural recordings are intended to be listened to over headphones. For best effect, close your eyes and visualize being seated in front of the stereo and turn it up a bit, as the dynamic range of the recordings are as good as the source.

     

    KEF LS50 binaural recording (53 MB wav DR12)

     

    I chose Mark Knopfler’s Back on the Dance Floor for a couple of reasons. It is a rock recording, with DR10, downloaded from iTunes simply as a “typical” recording. The drums and instruments are well recorded with a few notes of Mark’s famous “Money for Nothing” guitar sound resonating throughout. But most importantly, it is a simple sparse dynamic recording with Mark’s vocal up in level in the mix. This gives us a good opportunity to focus on the vocal tone and make some direct judgements when we listen to comparison recordings.

     

    Disclaimer: The binaural audio clips are not full song recordings and conform to the spirt of “fair use” for copyright material for the purpose of education and research. The author nor the publisher derives any financial benefit from these audio clips. The binaural recordings were made at 44.1/16.

     

    How does it sound? Remember you are listening to the speakers plus room sound combined. The binaural effect is intended for one to perceive feeling like you are situated in the acoustic environment. To my ears, the LS50 has a neutral tonal balance with some decent (perceived) bass from a 5.25” woofer in a larger living room area (30 x 16 x 8 ft). Not overly bright (yay!). Not much low frequency response, but you don’t miss it due to the nice neutral balance of this mini monitor. Sounds full, not thin.

     

    I can perceive a little bit one note-ish or coke bottle bass character effect at 100 Hz, due to room acoustics, but otherwise nice and smooth. Mark’s vocal sounds clear and the drums and cymbals sound dynamic to my ears. For me, I always envision being at the club or concert hall listening to the band live, as how I want the auditory scene to sound in my living room. 

     

    The LS50 mini monitors throw a huge image, as the off axis response is as good as the on axis response, especially in the vertical plane as well as horizontal. A key Toole figure of merit that results in a good sounding loudspeaker in a typical living room environment. The KEF whitepaper goes into detail on the variety of tech that makes the drivers and baffle subjectively disappear when listening. You can hear how big the image is on the binaural recording. KEF’s computer aided design has really paid off in making this mini monitor sound much larger than its physical size indicates.

     

     

    LS50 plus Rythmik L12 dual subs Objective Measurements

     

    I patched in the Rythmik dual L12 subs using Audiolense to supply the linear phase digital XO at 70 Hz and time alignment to the LS50’s. Additionally, Audiolense applies so called Digital Room Correction (DRC), both in the frequency and time domains. The combo of subs and DRC fill in the low end frequency response and gets rid most of the nulls at 70 and 80 Hz:

     

     

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    Pretty good given that the LS50’s are located right in a deep null, relative to my listening position. It is just sheer laziness on my behalf to not have moved the JBL 4722’s out of the way and placed the LS50’s there, where I know there is no deep null, as I have measured it before, with a variety of speakers. Also, I spent all of 5 minutes with the Audiolense correction, with no fine tuning. But close enough for rock and roll, as it is a pretty narrow dip of 5 dB as opposed to 20 dB null relative to 100 Hz in the measurement of the LS50 by itself. I wonder if we can hear the null?

     

    While I could have set Audiolense to only correct below the room’s transition frequency, (i.e. Schroeder frequency) that is often recommended, I went for the full frequency correction, as we want to make a few comparisons. I used the exact same target frequency response design as my JBL 4722 plus subs, so it would have also corrected for those little 1 dB high frequency bumps as measured on the LS50’s with no eq. Here is the objective comparison:

     

     

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    Still amazing to me how close the LS50’s are to my preferred target frequency response right out the box. You can see the little high frequency bumps on the LS50’s, with no eq, at 2 to 3 kHz, 5 to 6 kHz and near 20 kHz. Had I taken the time to position the LS50’s correctly, I suspect those bumps would be gone. It will be interesting if we can detect an audible difference in a comparison. But before we get to that, let’s listen to the LS50’s with the dual subs, which we see measures almost identical to out of the box LS50’s beyond 100Hz.

     

     

    LS50 plus Rythmik L12 dual subs Subjective Listening

     

    Here is the same Mark Knopfler tune, at the same level, as with the LS50’s, except added dual subs and my preferred frequency response target, which is virtually identical to what comes out of the box with the LS50’s

     

    KEF LS50 plus subs binaural recording (56 MB wav DR11)

     

    How does it sound? Certainly on my NAD HP50 headphones I can hear the extended bass response.

     

    Let’s see how it sounds when we compare the LS 50’s directly with the LS50’s plus dual subs on the same track. The Rythmik L12 subs are Rythmik’s entry level sealed sub for about $540 each. Rythmik’s subs with direct servo tech sound tight and musical to my ears.

     

     

    LS50 versus LS50 plus dual subs subjective listening comparison

     

    A common task working with Digital Audio Workstations (DAW’s) is to import tracks, line them up and switch back and forth to compare. That’s what I did here. I took the two binaural recordings and imported them into my DAW, lined up the tracks to be close enough to sound synchronized:

     

     

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    The top binaural stereo track is the LS50 and the bottom track is the LS50 plus dual Rythmik L12 subs. One is also seeing the DAW automation below each track where one track is unmuted for 10 seconds and then it mutes and switches to the other track for 10 seconds, and so on. In other words, every 10 seconds we alternate from one binaural stereo recording to the other.

     

    We start with the LS50, and then switch to the LS50 plus subs for 10 seconds, and then switch back on the LS50 for 10 secs and so on, ending on the LS50 with subs. Listen closely as the first 8 seconds is mostly intro and after two beats of the bass guitar, you are hearing the LS50’s plus subs. Meaning 10 seconds goes by quick as the first 8 seconds is the intro…

     

    LS50 compare to LS50 plus dual subs binaural recording (37 MB wav DR11)

     

    How does it sound? It may take a number of listens to tune into the differences. You may notice a “splice” or audible tick sound when the track switches. I left those in most places on purpose to give folks an audible cue when the track switches to the other binaural track. Some switches don’t make the tick sound, and requires a bit more concentration to hear the transition. It’s good ear training.

     

     In some switches, especially with the full on vocal in the chorus, it is tougher to hear the difference. But when it is just the drums and bass are playing, it is easy to hear the full range dynamic sound with the subs and fine tuning of the tone. Fuller sounding to my ears and not quite as boxy sounding. In some switches, I can hear the tone change. It almost sounds like a small pitch change.

     

    There is one switch near the beginning where the drums almost jump out when switching from the LS50 to the LS50 with subs. I checked the levels to make sure everything was properly level matched and could not find any errors. That’s also the same switch where I can hear the tone change with the drums are almost lower pitched when listening to the LS50 plus subs. Sounds more full range or “bigger” sounding to my ears.

     

    The vocals are a bit harder to tell apart, especially during the chorus with the layering and female voices, sounded more similar than different in a couple of switches to my ears. Now let’s compare this set up with the JBL 4722 with subs using the same target neutral frequency response.

     

     

    JBL 4722 plus subs Objective Measurements

     

    I have covered off detailed objective measurements of the JBL 4722 with dual Rythmik subs before and not going to repeat here.

    Here are the JBL’s overlaid with the LS50’s, both using the same subs (different XO point) and same target frequency response:

     

     

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    That’s a close match. Getting into Bob Carver territory ☺ Had I moved the LS50’s right in place of the JBL’s, would have gotten rid of the last little bit of low frequency dip. Plus may have balanced out the 2 to 3 kHz bump a bit more. OTOH, at that frequency range, there is more reflected sound with the LS50’s and I would say it’s showing up in the REW measurement as added amplitude. Why is that? Audiolense’s frequency dependent correction windowing can be adjusted and in my case, at this frequency, (i.e. 2 to 3 kHz), Audiolense is correcting more of the direct sound, like a tone control. However, in REW, the acoustic measurement software used above, the time window is fixed at 500ms and letting more of the room into the measurement at higher frequencies, which is possibly reflected in the measurement. Which is correct? This is where ones ears comes into play as to what one prefers, a more direct sound or a more diffuse sound. 

     

    Even if I lined up the KEF’s perfectly in place of the JBL’s, they would still have more room sound as their directivity is considerably wider than the JBL’s overall. And likely not quite the emphasis in the 2 to 3 kHz range either.

     

    When we listen to the compare, can we hear a difference in directivity, even though the loudspeakers are tonally (i.e. frequency response is) very similar? First, let’s listen to the JBL’s.

     

     

    JBL 4722 with dual subs Subjective Listening

     

    Here are the JBL 4722 with subs to get used to their sound:

     

    JBL 4722 with dual subs binaural recording (68 MB wav DR12)

     

    Depending on when folks listened to the other binaural recordings, and remember the room sound, this recording is different in the sense that there is (much) less room sound and more direct sound as the JBL’s have a much higher directivity index than the LS50’s. Really, these JBL’s are intended to be used in Cinema installations with hundreds of people in a much larger room than a living room. So in my living room, it almost sounds like headphones with little room sound.

     

    This binaural recording I find has a more focused stereo phantom image in the center than the other recordings with the LS50. I would say mostly due to the increased directivity. It is not that the LS50’s don’t have an outstanding stereo phantom image, it is simply that with their wider directivity pattern, and at my 9ft listening distance, has more room sound in the mix and sounds more diffuse, and as a result, not as focused.

     

    I spent quite a few years in pro sound and recording studio control rooms. The former used pattern controlled speakers and the latter was in rooms that were pretty absorbent. I got used to liking more direct sound than diffuse sound. If I was a classical music lover and frequented concert halls, likely my preference would be reversed.

    As an interesting aside, these JBL’s are horn/waveguide loudspeakers crossed at 630 Hz. I do not find them bright or fatiguing in anyway, no matter how many hours I listen to them. Again, I point to Toole’s and Olive’s research on what makes for a good sounding loudspeaker in a typical living room environment. Neutral sound is neutral sound regardless of the device used to present it. But as we will hear, the directivity index of a loudspeaker determines how much of the direct versus reflected sound one is listening to and can be used to determine ones listening preference. 

     

    Let’s take a listen to David versus Goliath

     

     

    JBL 4722 versus LS50 both with dual subs subjective listening comparison

     

    Like before, I loaded up the two binaural tracks in my DAW and in ten minutes, edited it to swap tracks back and forth every 10 seconds:

     

     

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    The JBL 4722 with subs starts first and then the LS50 with subs starts 10 seconds later while the 4722’s are muted and then switch back again 10 seconds later. It is tricky though, as it is only the first two beats of the bass in the first 10 seconds of the JBL 4722 with subs that one hears, before it switches to the LS50’s with subs. That’s because the first 8 seconds is the intro with no bass, and so it is hard to hear the initial transition. But over the course of recording, it is obvious in spots when hearing lots of room and then almost no room where one can readily identify the difference in speaker directivity.

     

    JBL 4722 compare to LS50 plus dual subs binaural recording (45 MB wav DR12)

     

    Tone wise, they are pretty close. What do you think? There is a small tonal change, as I can hear the room sound being added with the LS50’s. You can hear it almost like a slap echo (that’s an exaggeration) on the drum tone and vocal. It does open up the sound, as it is a bit brighter. Sounds more diffuse.

     

    The low frequency sounds similar on both, even though I cross the subs at 45 Hz on the JBL 4722’s and 70 Hz on the LS50’s. Focus in on the kick drum plus the bass line and try to notice any changes when the track switches. Should sound pretty consistent. For fun, go back to the LS50 and LS50 plus subs comparison and focus in on the kick drum and bass line again. One should start hearing the individual notes in the LS50’s with subs, as each one is equal loudness, but some low bass notes are missing on just the LS50, other than the 100 Hz overtone.

     

    Just like the other comparison, it may take a few listens or so to start repeatedly recognizing one speaker versus the other. While we may form an initial impression, repeated listening while focusing on different aspects of the sound starts to gather a collection of differences and more importantly personal preferences. For example, KEF has done an excellent job on making their mini-monitor sound bigger than it is with their computer aided design around speaker and baffle dispersion characteristics. Does one sound bigger or larger than the other on the binaural recordings?

     

    One area up for discussion is the lower mids. I do hear a difference in the lower mids between the 5.25” woofer and the double 15” JBL’s. Mark’s voice appears to have more weight or lower mid tone behind it. Of course, that is subjective on my behalf. It is very close sounding, but maybe the added room sound to the LS50’s is masking that.

     

    Will be interesting to hear what peoples thoughts are on the comparisons.

     

     

    Conclusion

     

    I hope folks find the binaural recordings fun and educational. For me it was an experiment on multiple levels and if done again, I would:

     

    • have moved the JBL’s out of the way and moved the KEF LS50’s right in the same spot. This would have accounted for any low frequency null differences, as it is a known good location. However, I really did hear a difference with the LS50’s with subs with the -5 dB narrow dips at 70 and 80 Hz compared to the JBL’s with subs. Do you?
    • moving the LS50’s to the proper location may also account for the small bumps in the high frequency response. However, the overall room amplitude would still be the same, but the frequency distribution smoother perhaps. I could have spent more time toeing the LS50’s in or out a bit more and re-measuring for proper set up with a few initial listening tests to check the tonal balance. I just placed the Skylan 24” stands and put the LS50’s on top – done.
    • Try a smaller equilateral triangle with the LS50’s just to compare the direct versus reflected room sound to see if it was proportionally less, as one moves closer to the speakers. It should be…
    • Replace my microphone preamplifier with a studio quality mic preamp. I ordered one based on these shootout results. The Lynx Hilo ADC is noted for its transparency and that has been my experience, but the mic preamp I have now is not as transparent.
    • Try different music material. Open for suggestions.

     

     

    Having said that, the differences between David and Goliath (with subs) are not that big. No pun intended. The LS50’s are keepers. They sound excellent and a steal for $1000. I am happily listening to them now without subs but will be adding the Rythmik L12’s later when I upgrade the subs for my 4722’s. KEF, and the science, can predict a neutral sounding speaker in most listening environments. The LS50’s measure and sound neutral in my room. It is quite the engineering feat for a mini monitor to sound this good with this size image reproduction.

     

    Spend another grand to get a pair of subs and I think you would have a hard time beating that $2K combo as a full range system. One would have to spend a great deal more for something that may be incrementally better or simply worse if not based on sound engineering principles (i.e. spinorama). There is a point of diminishing returns to achieve neutral sound if that is ones goal. Of course, there are some SPL restrictions in the case of the LS50’s, but if you mostly listen at reference level (i.e. 83 dB SPL), and your room isn’t huge, these can easily do the job and sound neutral.

     

    I do think the LS50’s sound “bigger” (i.e. full range) with the dual subs. I point to near the front of the binaural comparison track between the LS50’s and LS50’s with subs where the latter jumps out when listening to one of the transitions that is mostly drums and bass. I hope I got the levels right, but could not find an error. It sure jumps out to my ears sounds more dynamic, full range, bigger…

     

    The big difference I hear when comparing the 4722’s to the LS50’s, both with the L12 dual subs, is the room sound due to the large directivity differences between the two speakers. This is after eq’ing (i.e. with DSP both in the frequency and time domains) both speakers and subs using the same target frequency response, which is pretty much exactly what comes out of the box with the LS50’s down to its low frequency cutoff. My JBL 4722’s are a fully optimized triamped system with linear phase digital XO’s, time alignment of drivers, tight frequency response tolerance across the bandwidth, yet the LS50’s with subs sound similar tonally. One can hear it on the binaural comparison recording. Does one sound bigger than the other?

     

    After repeated listening, there is quite a bit of room sound with the LS50’s, as compared to the 4722’s. Once ones ears are tuned to the differences, it becomes much easier to listen again and identify which speaker one is listening to. Both sound full range. Using the same subs for both, takes away the low frequency differences. However, I do notice on Mark’s vocal that it sounds fuller or deeper in tone on the JBL’s. I can’t be sure if that has to do with the cone/box size difference or the directivity difference where the room sound is changing the tone of the lower mids on the LS50’s.

     

     

    Next Steps

     

    There are many variables to making a binaural recording that is transparent and high resolution enough to convey the characteristics of a loudspeaker or any piece of audio equipment for that matter. Are the binaural mics in the ears correctly? Is my head in the same location from one recording to another? Level matched correctly? And so on.

     

    However, I think with care optimizing the recoding chain and looking at how to adjust for individual HRTF, binaural recordings offer another level of equipment review experience on an item that you may not get to hear in person and can shed some light on its audible performance. Even if only the relative comparison is used, it is still a useful tool. In the case of completely opposite loudspeakers eq’d the same, one can hear the audible difference between a speaker with wide directivity versus as speaker with narrow directivity and what your preference might be. 

     

    Of course, there is no substitute to hearing the equipment “live” and perhaps in your own home. However, I am suggesting that it is time to kick up audio reviewing a notch by providing music lovers and gear listeners with more than just words. This approach can be used to identify fine details between gear not only over loudspeakers, but headphones as well. In the case where we might want to eliminate the room and listen to two different DAC’s for example. Sure, there are issues with HRTF’s and binaural mic placement, in addition to the myriad of different sounding headphones, but if there is a relative comparison change that is audible, then it would be captured in the binaural recording and available for all to hear.

     

    I am thinking of adding this ABX Switch Comparator to the mix to make it even easier to switch and record the comparisons, as opposed to having go through an editing stage. It would also make the process more reliable with less steps where things can go wrong.

     

    Based on this experiment of comparing the KEF LS50 with the JBL 4722, I feel I have only scratched the surface of what the possibilities are. This opens the door to compare digital signal processing as well, not only digital room correction products, but surround sound processing, upmixers, digital filtering of any kind, etc.

     

    As you may know, I am big on measurements, and will continue to do so, along with perhaps getting into electronics and digital signal processing measurements. More importantly, I wanted to find a way for folks to listen to the device under review, whether by itself or through a comparison, as added review information that is not currently available. I feel my first experiment comparing two very different loudspeakers and being able to audibly hear the difference is hopefully useful information. 

     

    I have a few details to iron out to make the binaural recording process predictable and repeatable, but I think that it will be worth the effort. I always found it odd in “audio” equipment reviews that up until now, there was no way to listen to the device under test. Hopefully, this approach will change that.

     

    Happy New Year and Enjoy the Music!

     

     

    image18.jpeg

    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.

     

     

     

     

     

     

     

    image19.jpeg

    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.

    Edited by The Computer Audiophile



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    Congrats Chris on the site refresh! All the best for 2019!

     

    Mitch: Wow dude. You have outdone yourself with that binaural A/B audio track :-). Agree "the differences between David and Goliath (with subs) are not that big"! All the more remarkable considering that image of the LS50 sitting beside the 4722 behemoths... A beautiful demonstration of your skill and the power of DSP processing (and Audiolense particularly in this case) in achieving the intended sound.

     

    Just add a screen between the listener and speakers, and you can offer the "Barnett Challenge" :-).

     

    Happy New Year!

     

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    With my second system. Speakers first and headphones after.

     

    Kef LS50 plus subs vs JBL 4722 plus subs

     

     

    foobar2000 1.4.1

     

    With speakers or headphones is very easy to differentiate ALL files, too easy!

     

    * KEF Q100 5.25" coaxial speakers tweaked and modded: it is very easy.

     

    * Takstar ts-671 open dynamic headphones tweaked and modded: it is very very easy.

     

     

    JRMC 24.0.72 64 bits

     

    The same but more easy

     

     

    By the way, amplification?

     

    Note: I have my Win 10 Pro 1709 x64 very very very optimized to play multimedia. Before summer only very very :)

     

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    Mitch, you've nailed it again.

    Love your observations & articles.

    Rare combo of logical, straight forward writing. Explained so a chunkhead like me can understand & read the entire copy.

    Sorry but, you can elucidate audio like Richard Feynman could explain astrophysics.

     

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    Hi Mitch. Happy New Year. Once again, I appreciate your thorough work. Yes, it takes a while to read all the "pages", but it's worth every paragraph. Thumbs up.

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    I wonder what the effect is of sympathetic resonance with the sensitive JBLs present in the room when the small KEFs playing.

     

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    On 1/1/2019 at 11:34 AM, Archimago said:

    Congrats Chris on the site refresh! All the best for 2019!

     

    Mitch: Wow dude. You have outdone yourself with that binaural A/B audio track :-). Agree "the differences between David and Goliath (with subs) are not that big"! All the more remarkable considering that image of the LS50 sitting beside the 4722 behemoths... A beautiful demonstration of your skill and the power of DSP processing (and Audiolense particularly in this case) in achieving the intended sound.

     

    Just add a screen between the listener and speakers, and you can offer the "Barnett Challenge" :-).

     

    Happy New Year!

     

     

    Thanks Arch! @Archimago  Happy New Year man. I have some plans for this binaural approach moving forward.

     

    Keep up the excellent writings!

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    On 1/1/2019 at 11:12 PM, STC said:

    Mitchco, thank you for a meaningful comparison of different speakers. Meanwhile, the audio stops at 3:10 for https://cdn.computeraudiophile.com/article-images/2019/0101/mitch/JBL 4722 compare to LS50 plus dual subs.wav . 

     

    I believe you changed the recorded sound at 3:00 but it stops after 10 seconds.

     

    Hello @STC Each recording is a random length and have different start times... Perhaps I am misunderstanding your question?

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    On 1/2/2019 at 7:14 AM, maty said:

    With my second system. Speakers first and headphones after.

     

    Kef LS50 plus subs vs JBL 4722 plus subs

     

     

    foobar2000 1.4.1

     

    With speakers or headphones is very easy to differentiate ALL files, too easy!

     

    * KEF Q100 5.25" coaxial speakers tweaked and modded: it is very easy.

     

    * Takstar ts-671 open dynamic headphones tweaked and modded: it is very very easy.

     

     

    JRMC 24.0.72 64 bits

     

    The same but more easy

     

     

    By the way, amplification?

     

    Note: I have my Win 10 Pro 1709 x64 very very very optimized to play multimedia. Before summer only very very :)

     

     

    @maty Cool! Which recording did you prefer? You can find the amps I used in other articles...

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    On 1/2/2019 at 6:05 PM, Milt99 said:

    Mitch, you've nailed it again.

    Love your observations & articles.

    Rare combo of logical, straight forward writing. Explained so a chunkhead like me can understand & read the entire copy.

    Sorry but, you can elucidate audio like Richard Feynman could explain astrophysics.

     

    @Milt99 You are too kind, thanks. Fan of Feynman 🙂

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    On 1/3/2019 at 12:36 PM, JR_Audio said:

    Hi Mitch. Happy New Year. Once again, I appreciate your thorough work. Yes, it takes a while to read all the "pages", but it's worth every paragraph. Thumbs up.

     

    Happy New Year Juergen @JR_Audio Thanks for the thumbs up. Yes, I write verbose 🙂 

    All the best!

    Mitch

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    15 hours ago, Tin said:

    I wonder what the effect is of sympathetic resonance with the sensitive JBLs present in the room when the small KEFs playing.

     

     

    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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    1 hour ago, mitchco said:

     

    Hello @STC Each recording is a random length and have different start times... Perhaps I am misunderstanding your question?

     

    The said track is 4:30 long. You stopped the music after 3:10.

     

    And in another track (https://cdn.computeraudiophile.com/article-images/2019/0101/mitch/LS50 compare to LS50 plus dual subs.wav)  you stopped the music at 3:00. The total length was 3:43.  I was just curious to know why instead of just snipping away the silence.   

     

    And once again, I am grateful for the binaural recording of the speakers playback. I think this is the best way to judge a review and I regular use the cheap Roland CS10EM and have been looking for other system's binaural recordings.  Hopefully, you would also choose some classical music and ideally the same music for all of your future reviews.

     

    Warm regards,

    ST

     

    p.s. @The Computer Audiophile ,  For your kind attention, I am unable to remove the format after the link in para two. 

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    @mitchco, great evaluation. I always enjoy reading your articles. 

     

    Do you have any idea if these results can be obtained using the active version of the KEF LS50, the LS50W’s? I’m thinking maybe not since the LS50W’s are active and there’s no way to get the audiolense corrected subwoofer signal into the LS50W signal path. I’m unsure given the LS50W’s only have a subwoofer out. 😐 

     

    If I can’t build it with the LS50W’s I might just look at replacing them with a pair of non-active versions and build it that way. Your results are amazing and previously I thought I could only get these results with something much more expensive like the Dutch & Dutch, Kii’s, or Genelecs. The fact I can get measured, repeatedly good in-room audio performance for under $3000 is amazing 😉 . Kudos to you for putting this evaluation together. 

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    6 minutes ago, hionhifi said:

    @mitchco, great evaluation. I always enjoy reading your articles. 

     

    Do you have any idea if these results can be obtained using the active version of the KEF LS50, the LS50W’s? I’m thinking maybe not since the LS50W’s are active and there’s no way to get the audiolense corrected subwoofer signal into the LS50W signal path. I’m unsure given the LS50W’s only have a subwoofer out. 😐 

     

    If I can’t build it with the LS50W’s I might just look at replacing them with a pair of non-active versions and build it that way. Your results are amazing and previously I thought I could only get these results with something much more expensive like the Dutch & Dutch, Kii’s, or Genelecs. The fact I can get measured, repeatedly good in-room audio performance for under $3000 is amazing 😉 . Kudos to you for putting this evaluation together. 

    I use KEF LS50 Wireless speakers with a KEF R400b sub woofer and it sounds great. I cross the sub over at 70 Hz and cut the LS50s at 70 Hz with the KEF Control app. At the moment there is no way of configuring the impulse response to time align the subs with the main speakers, and there is only a phase switch on the R400b to switch to out of phase. I could physically move the sub backwards and forwards though instead, and I think I'm going to get a UMIK-1 microphone and REW to tune the sub woofer via measurements.

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    3 hours ago, Richard Dale said:

    I use KEF LS50 Wireless speakers with a KEF R400b sub woofer and it sounds great. I cross the sub over at 70 Hz and cut the LS50s at 70 Hz with the KEF Control app. At the moment there is no way of configuring the impulse response to time align the subs with the main speakers, and there is only a phase switch on the R400b to switch to out of phase. I could physically move the sub backwards and forwards though instead, and I think I'm going to get a UMIK-1 microphone and REW to tune the sub woofer via measurements.

    I see. Mitchco is using Audiolense to supply the linear phase digital XO at 70 Hz and time alignment to the LS50’s. He’s also using , Audiolense to apply DRC, both in the frequency and time domains. The combo of subs and DRC fill in the low end frequency response and gets rid most of the nulls at 70 and 80 Hz. It doesn’t appear that the LS50W built-in controls offer enough horsepower or granularity (ie, phase control, bass extension, sub out low pass frequency, sub gain, sub polarity, wall distance) to achieve the same results Mitchco is getting using Audiolense.

     

    I suppose the only real way to know if the KEF’s/Rythmik sub can be integrated to achieve the same in-room response is to measure them in a similar way done in the article.

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    2 hours ago, esldude said:

    Man, your speaker reviews should be the gold standard.  They are the Gold standard.  

     

    Binaural just doesn't work well for me.  I actually got a better sense playing this over a pair of speakers.  

     

    Your results are very, very impressive.  I've got two suggestions/requests if you like. 

     

    One is could you record both speakers up close and use that instead of binaural or maybe you've tried that.  

     

    The other is just a different approach.  How about putting one speaker in one channel and the other speaker in the other channel.  Letting them play together.  You'll probably want to do that in the real physical world and do a binaural recording of that.  I think that might be the most impressive thing to show. Maybe alternate sections like you have between a matched pair of speakers and the two different speakers in each channel.  

     

    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.

     

    ART%20Pro%20MPA%20II.JPG

     

    Thanks for the approaches. Good idea on one speaker in one channel and the other in the other channel...

     

    Cheers! Mitch

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    On 1/5/2019 at 7:39 AM, mitchco said:

     

    @maty Cool! Which recording did you prefer? You can find the amps I used in other articles...

     

    Well, I do not like any. Something more the LS50.

     

    In my first system (Woofer 10.6", tweeter and supertweeter (19 kHz), kidnapped by family and TV) I like more the music without  EQ, only Direct. When you EQ > 200 Hz you modify the phase too: the human ear is able to appreciate the variation, unlike < 200 Hz.

     

    I think is better idea only EQ < 200 Hz, and to have speakers with flat response. And EQ only with attenuation.

     

    Films, better with Roon EQ off course.

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    Thank you, Mitch.

     

    The recordings were awesome and really took this review to the next level.

     

    To my mind, if money and space were no object, the JBL's are hand's down the winner. Their sound felt more natural and balanced. The song coming out of them had less of a reproduction feel, like the singers were present in the room. In contrast, the KEF's I coldn't shake the feeling that the song sounded like a playback of recording made in a studio. A very good recording, but a studio all the same. It didn't make me feel "presence" for lack of a better word that the JBL did. A little too "clinical" may be.

     

    Next, the KEF's with and without sub's were interesting to me because the difference is very similar to what I experience listening to my pair of Emotiva Airmotive 6s" powered monitors with and without sub's. Without sub's, it sounds nice and perfectly clear, but there's something missing... it doesn't get my body responding to the music. As soon as the sub's turn on, though, it's like the bottom half of the music comes alive and now I can feel it. At the same time, if I stop and consider it, it also feels a little made-up. Too much energy underneath. That is also something I struggle with on my sub's -- keeping the bottom from getting too strong where it starts to be fake. And again, I don't get that "fake" feeling from the JBL's.

     

    I reckon the million dollar question is whether it's from the room and the speaker placement that could be easily solved, or something else, like directivity, that can't be captured without big boxes like the JBL's. In any case, I am looking forward to more reviews and more binaural recordings.

     

    Many thanks and much appreciation,

    Allan F.

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    This was awesome - thanks so much! I have a very soft spot for the LS50s and until a few months ago they were my mains (partnered with two JL Audio subs). I still maintain they are one of the few true bargains out there in this crazy "hobby". 

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    ps. When I started with AudioLense early last year, I was looking for a mic preamp to go with my RME ADI2-Pro ... it seemed like many of them added some kind of signature or colouration which I guess is desirable to many recording engineers (can we still not add any of this in post?). One of the few I could find that seemed more suitable for accurate measurements was the Grace Design m101 ... pretty pricey but bit the bullet, been happy so far. 

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