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  1. 3 points
    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?
  2. 1 point
    Thank you for your kind words. This process has been enormously challenging and time consuming, but results (so far) are immensely rewarding. I never imagined sound of this level of quality was possible, in this space or otherwise. I remember when I first moved into this house in December 2012 and set my system in the living room for the first time. The sound was so disappointing. My original plan was to try to finish part of the basement for a dedicated room, as soon as I could afford it. However, the basement options were full of ugly compromises. In one area, I would have 14 feet of width but would have to deal with ceiling obstructions with only 6 feet overhead clearance. The other part offered a full 7 feet of headroom but only 10 feet of available width. I had to come to terms with the fact that the basement options would be suboptimal regardless and decided to try to make the best of the living room space instead. Today, I could claim to have a set up that approaches "world class" performance, all while leaving the living room largely functional, albeit with lots of weird looking panels and diffusers. Thankfully, my wife has been very accommodating. Her skepticism toward acoustic treatments melted away once she heard the difference. She also happens to be quite the bass lover, lucky me! ... Some day I need to update the first posts on this thread to describe my "current" configuration. Right before @lowerFE's visit, I migrated my speaker DSP configs to use FIR filters almost entirely. I also modified the crossover to 850 Hz LR8 (acoustic). The FIR filters are much cleaner and more precise than the mess of biquads I was having to maintain. The horn/woofer crossover is also linear phase, which I opted for not so much for sound quality improvement but to eliminate group delay that confounded my tonal balance calibration method using short FDWs. The result provided a significant improvement, albeit not as dramatic as some changes in the past. Still, it was worthwhile enough for me to demo with the FIR filters, despite the fact that the bass still needed work. So @lowerFE was able to hear the speakers sounding as good as they ever have, but the bass was not as good as I think it could have been. In fact, I ended up making substantial changes on Saturday night, between his visits. On Saturday, the main/sub XO was linear phase, and I ended up redoing everything to minimum phase XOs and less aggressive shaping to reduce pre-ringing. That was kind of a hard lesson for me, which is that pre-ringing really does bad things to bass transient response and tactile sensation. The problem was most obvious to me when listening to the Danley fireworks. I could actually perceive the pressurization before the bang happened. Even with those changes, some pre-ringing persisted and is present in my current config. I don't know how perceptually important that is though. Since @lowerFE left I've EQed down the 70-100 Hz range a bit, as it was subjectively too strong, but the bigger change was to move my bass boost from being centered at 70 Hz to being centered at 155 Hz instead. I decided to try to better mimic the floor gain from a "typical floor standing speaker". I had tried bass shelves at higher frequencies like that before, but it seemed to work a lot better this time. The extra mid bass really brought more punch and overall loudness to the table. Now I'm trying to figure out how to reduce pre-ringing further while maintaining smooth frequency response, keeping excess group delay in check, ensuring coherent summing across multiple channels, and doing all of this at every seat location. It's a remarkably complicated problem, and while I have powerful DSP to attack it with, it's not at all obvious how best to apply this capability. I also have a problem of a rattling window pane (at around 60 Hz, unfortunately), so I am trying to reduce the bass build-up in that corner to keep it from rattling as much. I intend to eventually try to optimize using an automated algorithm, but automation is useless without a precisely defined objective. And in the long run, I expect I won't be able to get the results I want with the equipment I have. I still intend to replace the MBMs I have. The open question is *where* I'm going to put the new MBMs. I can put some of them behind the sofa like the old ones. I can also put some of them on top of the subs, between the subs and left/right mains. (The "pseudo-line" approach.) And I can put some up on the shelve above the TV, adjacent to the center channel. The locations behind the sofa are starting to fall out of favor with me because it's difficult to avoid pre-ringing problems. In fact, I can't really avoid pre-ringing in the dining room and kitchen areas when using behind-the-sofa MBMs without using multiple switchable DSP configs, which I'd like to avoid. So I'm curious if I can get away with MBMs on the front stage only. I think the approach has potential, given how the center channel measures. That is something I will investigate in due time. Some time, I might start a thread about bass phase response / group delay. It seems to be a substantially neglected issue with regard to system optimization and may have a strong bearing on tactile response performance. While it seems counter-intuitive that minimum phase crossovers may (often) be superior for mains/sub crossovers, minimum phase systems actually appear to have the properties we want most. We want as much energy as possible to arrive at the start of the impulse. Too much positive excess group delay, and energy does not arrive until too late to contribute to perceived impact. (Post-temporal masking effect.) But any pre-ringing has the effect of shifting the perceptual reference point, the "start of the impulse", to a place where there's very little energy at all. (Pre-temporal masking is very weak.) So what achieves these goals? For a particular magnitude response, the minimum phase response maximizes the amount of energy in the initial impulse. I suspect that this is what's needed for the best tactile "kick".
  3. 1 point
    Had not got T5 yet on video but will eventually. People love to poop on Michael Bay and T5 has serious issues but in a hobby for A/V..... T5 brings it. Interested in the Atmos track and if it is (better be) a remarkable improvement from T4's barely-Atmos track. And yes... let's bring back the days when 20hz was cool cuz it still is, imho.
  4. 1 point
    Reading this (above) makes me happy. SME builds, measures, makes adjustments, attention to details that surely can not make any difference - but it does. Then he - SME - describes the amazing sound, well, what does he know that all the others don't.. And the proof is in hearing and experiencing yourself. As lowerFE did. When you focus on the parts that are important for sound quality, and fix it, you actually get results that matters.
  5. 1 point
    Is no one going to talk about the audio in Transformers "The Last Knight" whenever Megatron is on camera? The audio has been lightly brushed on here at Data-Bass but I don't recall anyone going into detail. I SpecLab'd a few scenes last night and when Megatron lands in the salt flats the hottest spot is centered at 20 Hz. Sure it's no 7 Hz WOTW, but the sound in the movie makes it worth watching and also using for demo's. I haven't seen much talk about it so I'll go out on a limb and say that I love the proper audio in this movie.
  6. 1 point
    Yes, I did generalize for a tapped horn, and now that I think about it, I might not be correct even for that case. Several 10s of milliseconds sounds very high for "room acoustics" effects. A full cycle at 60 Hz is 17 ms. If you are delaying more than that (in addition to distance and "internal" effects), then you are probably adding unnecessary group delay, which likely impacts transient response sound quality and slam. FWIW, I've been studying this problem quite intently lately, trying to improve integration between my speakers and subs. Unlike most people, I have practically unlimited DSP resources to throw at the problem, where the only real practical limit is latency. I would say that the processing capabilities built into AVRs and most processors are woefully inadequate for achieving an optimal outcome. The"THX "LR4 sub/sat crossover" is largely fantasy that rarely occurs in real world conditions. The best that most people can do is a brute force evaluation of different XO frequencies and sub delays, where typically response is only optimized on one channel and at one seat. Yet even this effort requires more sophistication than most users are capable of. (Readers of DataBass and some of those who read AVSForum are obvious exceptions.) No wonder a lot of people prefer bass from 2 channel full-range speakers vs. subs. While the in-room "placement" of the LF drivers in such speakers is non-optimal, the XO is (ideally) optimal for that placement. I've noticed that good anechoic-flat full-range speakers, when pulled far enough from walls, can deliver impressive slam; whereas many sub systems including many with big horns or many large drivers struggle in this respect. My recent experience suggests that phase (or rather group delay) effects are more important than most people realize. And it's not what people think. I.e., a ported sub isn't necessarily sloppier than a sealed sub, though that obviously depends on the competence of design. Such effects are largely minimum phase. (A good thing.) Rather, it is the excess group delay, which arises from crossovers and distance differences that appears to be important. Pre-ringing in particular seems to really kill tactile slam, and it should be noted that FIR filters are not the only way to introduce pre-ringing into a system. Pre-ringing can arise merely from placements and/or delay settings. Any situation in which sound from a sub may reach the listener before sound from a speaker potentially involves pre-ringing. Rooms with rear subs are likely to exhibit pre-ringing for rows behind the one used for calibration. What's not at all clear is where the perceptual thresholds lie for hearing and feeling of pre-ringing effects. Anyway, I still have a lot of work to do here, and at some point, I may try to do some more formal testing of excess group delay effects, including pre-ringing, as this information would be very useful for optimizing sub systems for multi-listener environments.
  7. 1 point
  8. 1 point
    Though I'm sure there are guys stateside that can do it, and are a lot better at soldering too. I just thought posting a guide was a nice gesture as these amps are so popular in the diy crowd. Modding them would make them less crappy for powering infrasonic subs
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