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lowerFE

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lowerFE last won the day on October 17

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About lowerFE

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  1. I respect Harman's research as well. Very thorough and well executed. However, there is a weakness. The research, and all of its data is based on existing speakers back in the day. Essentially, it is just simply finding out the most preferred speaker that has already been made. It makes no attempt in finding the theoretical optimal sound signature. Therefore, if there is a sound signature that is preferred over anything else existing on the market, but does not currently exist in a speaker due to technological limitations, then it would not be found. A subjectively flat response is exactly curves (since it changes) that a passive speaker cannot do. I argue that having equal loudness compensation is half of the equation in the ideal most preferred curve. The other half is full range constant directivity down to the schroeder frequency. Regarding whether the curve should be statically applied based on a volume level versus the instantaneous RMS level of the signal, I think both have merits. Currently I am on the former, but I'm thinking of moving to the latter. The reason is because I think a static equal loudness compensation based on a volume level is most optimal when the reference volume is known, such as in surround sound formats. This is the closest to real life since the frequency response of individual sound sources do not change depending on the volume. However, when we don't know the reference volume, I'm inclined to use a dynamically applied compensation. This is because for most music, we simply don't know what the reference volume is. The average level of songs can vary quite widely depending on content. Also, for most music, especially for any music that contains electronic instruments, there is no "reference volume" anyways. We have no idea what "real" really sounds like. Therefore, there is little purpose in trying to achieve "realism", and the goal should be "good sounding". When the reference volume can differ rather dramatically between song to song and genre to genre, a dynamically applied compensation will have a better chance of sounding correct since it is based on the actual SPL heard at the listening position. The obvious exceptions are classical music, or any music with large dynamic swings since they should be left as it is instead of being modified, but I hardly listen to music with real instruments.
  2. I am not saying old people don't like extended treble response. I'm saying people with hearing damage don't like extended treble, and that is generally old people. That's like saying good speakers sound good, and they're generally expensive. Doesn't mean expensive speakers are good, just happens that expensive speakers generally sound good. There are lots of older people that love the sound of my speakers. Had a retired man who cranked metal music on my speakers, and cranked it LOUD, and he told me it had the best cymbal crashes he's ever heard! There is a WORLD of difference between accurate reproduction on a headphone vs on a loudspeaker. There is zero crosstalk on headphones, which dramatically changes how imaging is perceived. There is no concept of direct vs reflected sound on headphones since it is all direct sound. There is no concept of directivity on headphones either. The amount of bass is dependent on the seal and fit of the headphone. Correlations between headphones do not necessarily apply to speakers. I was lazy and posted the same thing that I posted on other forums to this forum as well. The above is "dumbed down" so it is easier to digest for the average DIY'er. For this forum I should write something a lot more technical. But basically yes, it is just Audyssey Dynamic EQ, but a better version of it. Audyssey nailed the lower range, but not so much on the upper range. I still haven't gotten it as right as I could make it, but so far it has been a lot better with this than without it. You're right that the amount of boost that needs to be applied will be dependent on the source. My intention is not to get it right for everything because that's not possible. If you optimize for one song, it might introduce problems for other songs. Therefore, the goal is to apply a general broad stroke correction so it provides a positive benefit for ALL sources.
  3. I'm long overdue for an update. I've actually lately been too busy simply enjoying these speakers or giving people demos of these! But there were actually a number of big improvements that made night and day differences to the sound quality of these. I will talk about them over a number of posts. This post will be about my discoveries in sound signature preferences.The Universal Sound Signature PreferenceI'll start with a story. I brought this to an audio enthusiasts get together a few weeks ago as a bunch of people want to hear this speaker I've built. I set the speakers up in my friend's room, but I was having strange setup problems that I've never encountered before that took some time to fix. Since there was about a dozen people waiting and eager to hear this, for the sake of time I only did a rough setup that resulted in poor placements (speakers placed right against the side wall and above ear level) and did only a rough room correction to compensate. However, once it was set up, nobody wanted to leave. This is a room where at least half the people owned 5 figure sound systems at home, many had traditional speakers, some had tubes, some had huge horn speakers, and they all sat there, continuously adding songs to the queue, and listened to the speakers for over 4 hours besides a little break here and there to talk and discuss. The fact that they listened for over 4 hours tells me that everyone truly loved the speaker. Otherwise they would have simply left after a few songs and went to talk to other people outside.Unlike the traditional thought that people have different preferences in how a speaker sounds, where some people like their speakers sounding bright, dark, warm, etc. I believe there is a universal preference (with one exception), and now I have strong anecdotal evidence that supports this. This is going to be difficult to believe, but once you hear this, I think most of you will agree. I believe the universally preferred sound signature is one that is subjectively flat. I've tried this with over 50 people at this point, and it is clear that this is an appealing sound signature regardless what their original preference is. I've had people actually tell me this is very different from what he's used to hearing, and it changed his view on what is "good sounding".What is a "subjectively flat" sound?Now this is tricky. This is not flat, like a speaker with a flat frequency response, but subjectively flat. Our ears hear differently at different volumes. At normal volumes, our ears are less sensitive to bass, and to treble, but to a lesser extent. As the volume goes up, our ear becomes increasingly sensitive to bass and treble. This means that a speaker that measures flat will sound thin at normal volumes since the subjective frequency response that our ear hears will be a "semi-circle" shape where the bass and treble is rolled off due to the lower sensitivity of bass and treble. This is why many speakers sound better at louder volumes. This is because as the volume goes up, our ear's sensitivity to bass and treble gradually increases. This means that the speaker is sounding more and more subjectively flat as the volume goes up. We like a flat sound, which is why we like the speaker played louder because it is closer to flat. The same reasoning can be applied to why bright speakers sound nice at normal volumes, but becomes annoying at high volumes. At normal volumes, the bright sound compensates for our lack of sensitivity to treble, so the top end sounds subjectively flatter than a neutral speaker. But when you turn the volume up, the ear's sensitivity to treble increases, and now the ear hears a sound with too much treble, and we don't like it because we like a flat sound.What does this mean? What we perceive as sounding "flat" varies dramatically depending on the volume. In order to achieve the universal preference of subjectively flat, we need a speaker that changes its frequency response depending on the volume it is played at. This is not possible to achieve this with any passive speaker.So for a speaker to sound subjectively flat, there must be a bass boost and treble boost. It is not a straight boost either, but a continuous slow rising response starting from low midrange (around 400Hz) and into the very deepest of bass. A similar, but a much smaller rising response is needed for treble starting around 5000Hz. Isn't that just a V shaped frequency response? You must be shaking your head in disgust! V shaped??? Blasphemy!!! However, the response I describe here is almost impossible to do on a passive speaker since the boost required on the bass would require the speaker to lose over 10dB of sensitivity, and the inductor needed to start cutting at 30Hz is just impractical. This is why most "V" shaped speakers don't sound great. They are not getting the right target curve needed to sound correct. Even if they are through the use of an external equalizer, the amount of bass boost and treble boost needs to be different depending on the volume so it always results in a flat subjective response to our ears. The equalizer provides a static change in frequency response and it doesn't changing with volume, so it'll sound bad at higher volumes and create fatigue (too much treble) and boominess (too much bass). With my speakers, after a calibration it knows exactly what the SPL is at the listening position, so it can automatically adjust the bass and treble depending on the listening volume. This is the key to get the speaker to sound subjectively flat to our ears, and if done right, it sounds downright amazing, and just sounds right. The Exception(*) What is the exception? I've found that this is not true for people with substantial hearing loss, i.e. a lot of old people. This is the group that heavily favours a very rolled off treble sound. For some reason I don't yet know, these people seem to think treble is the devil. I would think with hearing loss, you would want MORE treble to compensate for their reduced high frequency hearing. However, it seems like people with hearing loss genuinely hate treble because for some reason it greatly irritates them. I brought these to the Burning Amp, where most of the attendees are well over 50. I ran a long 20 second frequency response sweep, which meant there were 10 seconds or so where the sweep is in the treble region. I noticed several people covering their ears during the sweep, and some looked like they're in pain. I got much less positive reception there, which is understandable because most of the speakers that were presented had, in my opinion, essentially no treble. And of course, these "treble-less" speakers got huge positive receptions, which is not surprising at all if hearing high frequency causes these people to contort their facial expressions.
  4. So after reading this thread over the past year and amazed and the technical depth and extreme attention to detail paid to the tuning of this system and going "man I really want to hear this!", I flew and went to check out this system. And boy what an amazing system to listen to! My mind was blown as I was amazed by one thing after the other. All the work put into getting the tonal balance of this speaker correct really paid off big time. The whole system just sounds really "correct", and the more I listen to it the more I'm amazed by it. I brought my Reference Mini's with me as a comparison, and there was a very obvious difference in sound quality. I thought my speakers sounded really great, but it sound noticeably "off" when compared to this system. The speakers had a fantastic amount of detail, and the transients are awesome! It felt like I'm listening to a pair of really good headphones (and few people realize how hard and impressive it is to achieve this), but I also get the enveloping sound that makes speaker listening so pleasurable. It's the best of both worlds. What's even more impressive is the bass. I don't think I've heard bass so tight and full sounding in a room, which is clearly due to the complex integration efforts of multiple subs and individual EQ's to get such flat bass over a large number of seats. The clarity and tightness is seriously impressive. Again, just like a headphone, and that is actually something I've never heard before from a subwoofer. It is straight up the best sounding bass I've heard in a room. Now when you also get the whole body physical sensation from bass, addictive is an understatement. One thing that is unforgettable and blew my mind is how great the speakers sound in the kitchen! I don't think SME has ever mentioned this, but it was indeed one of his goals. It was remarkable hearing a correct tonal balance with almost no treble roll off in a different room! I still can't believe this is achievable. It must be the combination of controlled directivity speakers and properly placed diffusers pulled this amazing magic trick of a feat. I've heard a lot of amazing home theaters, but this is the first time I heard imaging from surrounds. It was trippy to be able to pinpoint the location of the sound going across the rear stage. I really wish we watched an action movie and be able to so accurately track the position of the sound effects. This is even more impressive as I seem to clearly have less ability to hear imaging compared to other people. Speaking about imaging, the speakers reproduced phase manipulated music tracks far more accurately than anything I've heard so far. It must be the room treatments that are preserving the phase accuracy of the speakers. It was like "oh this is where it is supposed to sound!" I was also exposed to the dark secrets of the time domain in room correction. That was a revelation to me to be exposed to so much more information and tools to analyze room acoustics. Now it makes sense why and how the room is mucking up the sound. It's all in the time domain! Now I am able to correlate measurements and subjective judgment of how good (or bad) the room sounds. I have so much to dig and play around with now. Measurements really can tell you about how good something sounds if you look at the right things and how to interpret it properly. Thank you SME and his wife for being such amazingly gracious hosts. That was one hell of a weekend! Oh, and did I make it clear enough that your system sounds good?
  5. JTR Speakers Captivator 212Pro Discussion

    Very impressive results for such a small cabinet, driver size, and low cost. Of particularly noteworthy aspect of the performance, which Jeff kinda pointed out already, is how little difference there is between the long term output and burst output. I've never seen a passive system driven by a K10/K20 report such small differences. I wonder what's going on. In one way it can be seen as excellent design that maximizes long term output, in another one could wonder what's going on with the drivers that they can barely handle 100V during burst testing. Anyone wanna chime in?
  6. Little update. I just moved last week for a new job, so I didn't get a chance to really work on the speakers much to deal with moving. But for something fun, I improved the limiter design a bit to get a bit more maximum clean bass output from the speaker before the limiter clamps the output. I've wrote a lot about my speakers so far, but this time here's a video of the Reference Mini's doing ~107dB of bass and 109dB peaks. The listening position is about 8 feet from the speakers. For reference the TV is 40". I promised there will be bass!
  7. Oh I've been enjoying this, but not as much as I would like to because I've had way too many things to do in the past couple of months. At certain times it feels like working on the speaker is a chore that needs to be done. Granted it was a lot of technicalities like measurements and stuff, but now the real fun begins with all the DSP, features, especially since soon I will have a lot more free time to play and enjoy. I'm going to get Dirac soon for this speaker and it should be fun as that should be a big step forward in sound quality in a room. There's going to be endless amounts of tweaking and optimization that I will be able to do with this. I think that's the best part, being able to incrementally and continuously improve the speaker and have features or combination of features that exist on no other commercial speakers. When I get a breather I got to catch up on what you have done!
  8. Yes I did. That'll likely go into the next speaker whenever that happens.
  9. Oh it'll be done more than right. There will be lots of tweaking, but it won't be the kind of minute tweaking that a lot of companies do. I will be focusing a lot more on the stuff that makes a bigger difference in creating a better subjective listening experience. This means LOTS of various DSP features that has seldomly or never been used with speakers before, but done right. It'll take a lot more than 9 months!
  10. Another update. After learning about measurements for some time, I think I'm getting a hang of how to really properly measure speakers. I don't have anything to show yet, because I ran into problems doing accurate polar measurements. I will show measurements when I have a full set of measurements ready. A few things I noticed. Turns out bipoles are tricky little things. Maybe this is why there are hardly any bipole speakers. I have to use these vertically. The midrange response is rippled and has a dip around 200Hz in horizontal orientation because the baffle is much wider, and the woofer is off center. This causes various interferences due to the path length causing the rear woofer to not integrate with the front woofer properly. The issue is mitigated in vertical orientation since the baffle is much narrower and the woofers are centered. One unintended bonus from the 200Hz dip in horizontal orientation is that when placed vertically, the 200Hz dip appears in the vertical plane, and it is actually pretty close to the typical ceiling bounce cancellation frequency in a normal height room. So the problem of ceiling bounce is unexpectedly reduced. I cleaned up the phase of the speaker and used FIR filters to do the bass boost, baffle step, high pass, and clean up the phase from the 3-band compressor. The bass is significantly tighter now, which isn't surprising because I had 6 major sources of phase shift (8th order HPF, 26dB bass boost, 2 LR4 band splitting for 3 band compressor) and it really screwed with the time domain of the bass. I did a comparison between doing the DSP processing at 44.1KHz and 176.4KHz. The comparison isn't ideal because it isn't blind, and it wasn't instantaneous because JRiver has to be restarted to change sampling rate. I *think* the 176.4KHz had a little more clarity, but the difference is very small. I went back to 44.1KHz because the delay for 176.4KHz is really long at nearly 2 seconds. I need to find a way to process the bass at a lower sampling rate so I can have 176.4KHz for mid and treble without the long delay.
  11. Not yet! Far from it actually. There's a lot of DSP optimizations and tricks I need to add on this. But at least right now I can have some fun listening to music as I continue to work on this. I'll be a little less busy for the next month or so, so it is actually great timing to be enjoying the heck out of these things I can't even imagine for you. I've had problems where it only happens at a high enough volume. I'm sure that happens for you too, but for the stuff you work on the volume would be This came in heavier than I expected. It weighs 14.7 pounds each. It's a heavy little sucker, and it always surprises people when they try to lift it. Now I have a silly little idea in the back of my mind to make the next speaker I build as heavy as possible That ATC monitor is indeed amazing. That doesn't substitute measurements though. I have done some measurements, but I don't think they are totally accurate. Soon I will be doing extensive polar measurements on this speaker. Gonna do it really right this time around, but it'll take some time.
  12. Long overdue update. Been incredibly busy lately, so here's a look at the progress I've done with this speaker.I added a preamp board into the speaker. The amplifier needed 2.7V of input sensitivity to reach full output, but my output stage on my Xonar U7 only outputs 1V. This is made from the OPA1642 op amp. The second PCB is for filtering the noisy auxiliary power from the ICEpower amp. The preamp steps up the voltage by 4x. Even though I only need 2.7x, I used 4x to allow spare headroom for the DAC. Now I can finally get full power from the amps and really crank out the SPL.There were many problems along the way. I had a lot of buzzing problems! I had a ground loop buzz problem that took a lot of effort to find the cause, and it was because the RCA connectors were directly mounted to the baffle without an isolator. Even though wood is a terrible conductor, it was enough to cause a very slight hum that was audible since the amp is running full tilt. I had another buzz problem that was extremely peculiar as well, and turns out it was a few screws that were not tightened inside. I had another buzzing problem that was because the rear end of the passive radiator isn't completely flat, so the washers were rubbing each other at high excursions. Another buzz was due to wires slapping the baskets at high volumes. 4 different sources of buzzing, and this has to be the hardest game of whack a mole I've ever played!I did some more tuning of the speaker. I need a really high quality speaker to be used as a reference for this speaker. So I went to a friend's house to use his ATC SCM150ASL's as a benchmark and reference. Before the tuning, while the Reference Mini held its own quite well, the ATC sounded noticeably better in every single metric. The speaker sounds much better after the tuning, and sounds much more similar to the ATC except in the bass. The ATC is a bit bass shy, and I like mine with more bass.
  13. I decided to reread some of the old responses to see if I can have a better understanding of everyone's responses now. I suspect there were things that went over my head when I first read this almost a year ago. I understand what everyone's saying perfectly now. I even got new understanding reading it again now. I was even able to follow SME's math! Thank you everyone who shared their knowledge.
  14. JTR Speakers Captivator 118HT

    Very impressive results from such a high efficiency, pro style driver. I wonder what is the Cms on the woofer to get such great deep bass and upper bass efficiency. Amazing output from just a 700W amplifier. Looks like the driver had just enough excursion and linearity to produce the 25-30Hz region of highest excursion levels with the given power. Kudos for JTR for coming up with such a high performance subwoofer for such low price. The engineering is obvious to get the most performance possible with modest parts, and that's real engineering skills.
  15. Yes, I just need to add mass to it to drop the tuning. Tang Band has 2 versions of the passive radiator I use, one with 25g Mms and one with 55g Mms. Based on what I'm seeing it looks like I have the 25g version when I thought I got the 55g. I'll just add enough mass until it hits the desired tuning.
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