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SME

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SME last won the day on May 5

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About SME

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  1. SME

    Ricci's Skhorn Subwoofer & Files

    In practice, how much does CMS actually vary in different manufacturing samples (assuming the same batch of parts)? I know we see lots of variation when we attempt to do measurements, but that's not necessarily the same thing. The value obtained may depend a lot on the details of the measurement, and the value is known to be quite sensitive to temperature and humidity. Both of these kinds of things should be expected to affect both drivers equally.
  2. SME

    Ricci's Skhorn Subwoofer & Files

    I don't see how a pair of drivers in series could cause a problem. Three or more drivers, yes, but only two? Anyway, I installed a 3/4" wall between chambers in my D.O. sealed sub because I was paranoid about local acoustic loading effects and wanted to option to possibly run separate signals to each end at some point in the future. That pic looks great! I'm sure your neighbors love you.
  3. SME

    The Bass EQ for Movies Thread

    Do you know how similar the two tracks really are? I tested this out on the DTS track (no UHD here yet), and I'm seeing (post EQ) levels that are hotter than I'd expect, even for BEQ. One of the effects (SPOILER: select text to reveal <<< the destruction of Leia's ship >>>) clips not just the amps but my digital processor, which is pretty extreme. Note that my digital domain headroom is not based on 7.1 WCS but rather is a few dB higher than that required to drive the amp to max voltage. The PvA doesn't look *that* crazy. Are these just examples of extremely ULF-heavy broadband effects? Overall, the effects also seem a bit bottom heavy, and some of the ambiance and tension ULF seems rather overkill. Since I don't really how the tracks compare and can't measure them right now, I'm thinking of proportionally scaling back the correction until I have enough headroom and/or the bottom sounds a bit more balanced again. Perhaps it's another case, as with "Thor: Ragnorok", in which the two tracks are have substantially different bass profiles? Edit: I dialed back the BEQ to 75% (in terms of dB) and also made some minor broad shape adjustments (> 100 Hz), and the mid-bass slam is back and proper. I presume the latter changes were more important, but this BEQ was just too much for my system. Even at 75%, the aforementioned scene as well as (SPOILER: select text to reveal <<< Phasma falling into the flames >>> still clip in the amps at my chosen playback level. There's still plenty of infra power all over the place. Very nice! The overall level on the track is lower than typical, and I find it to be completely comfortable at MV "0" (equivalent to "-2" after dialnorm). The mixer must have liked less loudness or else his monitors sounded overly loud to him. Either way, the soundtrack quality is superb, easily better than TFA. Edit2: I watched this all the way through with the DTS 7.1 track at MV "0" (-2 with dialnorm) with guests and 75% of the correction applied. There was tremendous infra, but it honestly seemed a bit repetitive with almost every effect being very bottom heavy. The bigger on-screen events were rather disappointing because the effects were the same or weaker than for many other lesser events. Since I still don't know how close the PvA on the DTS track is to the Atmos track, I have no idea if my track was corrected as intended. Maybe the DTS track is ramped more aggressively or rolls off less in the ULF. The most impressive effect was the latter of the two scenes mentioned above that clips my amp, which unfortunately seemed only vaguely connected to anything obviously big on-screen. I don't know what frequency the effect focused on (mid teens?), but it was downright violent. I felt like my body was being tossed around like a jet flying through turbulence or something.
  4. I recall "Ex Machina" had a loud droning score toward the end and the DTS:X mix sent the score almost entirely to my surrounds. I turned things down a bit because I was worried about long term power effects.
  5. SME

    Raw data for just 1 system

    $ du -hcs acoustic-measurements 8.8G acoustic-measurements Bummer. No bragging rights for me. That also includes a lot of simulation output.
  6. SME

    Woofer for 40-250Hz?

    Ouch. It'd probably be a good idea to hook it up ASAP and check for coil rub being that the tolerances are very tight on those. I'm a little confused as to where you plan to use the AE vs. FaitalPro drivers. I thought you just needed one type of driver to cover 40-250?
  7. I got a conversion done. It's not really pro quality as I didn't do any dithering, but it should compensate for the mic cal down to 4 Hz: https://drive.google.com/file/d/1EylLR1mXkmaCI0mIjwQgPi7MkWVy0D1s/view?usp=sharing Anyway, the recording could benefit from some editing. It was hard to tell in a wave viewer where the good stuff is. It also has a couple of nasty pops, which I believe may be caused by EMI from the lightning flashes. I'm pretty novice with Audacity and didn't have any luck getting rid of them using its click removal plugin. Anyway, there's definitely thunder with very solid bottom in the recording. Oddly, the most impressive bass event doesn't seem to be caused by thunder. There's a lot of weird bass noise starting roughly around 56:30, and then a big ker-chunk right at 57:48. It's nearly -3 dBFS peak in the compensated version and almost entirely bottom end. Did you bump the mic or something?
  8. Do you have a narrow band cal file for your mic? If you can send me that and the audio, I can create a compensated version of the recording.
  9. SME

    Horn length extension on Othorns?

    LOL! If it's too loud, you're too old! It's like the equivalent of an SPL car in a listening room. But seriously, it's hard to argue with this point. If he actually ran the bass so hot as to use all the Othorn capability for movies, what's the point of having the Terraforms? Or are you trying to talk him into buying another 12 of them?
  10. A 45% on Rotten Tomatoes isn't, like, "Conan: The Barbarian (remake)" bad. And it looks like it's not terribly long either. Something like 103 minutes of constant wind noise?
  11. SME

    Horn length extension on Othorns?

    I see (now). Some details in the photo are hard to make out, what with all those huge boxes in the way. 😉 I think this is key. Models in Hornresp and whatnot are helpful to understand what happens in an idealized 2pi space, but when you stuff 8 Othorns into a tiny cinder block room whose dimensions are smaller than most of the wavelengths of interest, much of that goes out the window. How much footprint does that well and sump pump take up? I don't know if there is space for this, but what happens if you arrange them into two groups of four with all units firing into the front wall? Each group is two units wide and two units high and the width between the two groups is twice the width between each group and each side-wall. I'd also invert the unit on top so the mouths are closer to the ceiling, and maybe put them up on platforms to get them closer to the ceiling for better symmetry. Is there room enough in the left corner for that to work? I'm guessing the room is maybe 12 feet wide? So I guess that means 12" between the side wall and each group and 24" between the two stacks. Maybe that's too close. Or perhaps it works if there is enough distance to the front wall? Another option may be to cluster all eight (or just six?) subs in the center, still firing everything toward the front wall but forcing all sound to exit along the side-walls. In this configuration, the cabinets could be perhaps be angled to create expansions in order to reduce high order resonances and possibly boost output even more. Obviously, both of these options will work much better if the ceiling and right wall gaps are closed. Anyway, just throwing out more ideas here. I know if I had that kind of appetite for bass and a dedicated room, I'd probably just build my system into the structure itself.
  12. SME

    Sundown ZV4 18D2 - sealed enclosure

    Lower crossover can be easier to integrate because the wavelengths are longer so interference is more likely to be constructive. However, every situation is different, and there are pros and cons to different approaches. I wasn't sure how low your mains could go. Some other guy on here with horns was pretty much set on using 60 Hz, and I think I might have gotten you two confused. If your subs play well together to higher frequencies, it can often be helpful to cross above 80 Hz. I cross at 100 Hz FWIW, and in fact I currently have MBMs behind my sofa that contribute up to about 150 Hz on the FL/FR channels with optimized DSP to make sure everything plays together in phase. Bass localization is not an issue at all, but I'll probably change this configuration at some point in the future.
  13. SME

    Horn length extension on Othorns?

    EIGHT Othorns?!?! I don't doubt he broke windows. To be frank, if he is so concerned about getting the most performance possible from 8 Othorns, I suspect his health might legitimately be in danger, or else he just happens to like testing spaceship parts for launch worthiness in his spare time. To address the question directly, I am far from being an expert in these things, but what @StainlessSteve says here sounds right to me. The tapping effectively acts as a tune, where the horn between the driver and tap is 1/4 wavelength at the tuning frequency, below which native response drops with 24 dB/octave, plus the roll-off introduced by the requisite HPF to prevent unloading. In other words, any boost in extension achieved by reconfiguring the cabinets will be mostly overwhelmed by the natural roll-off of the systems. An optimized configuration could maybe help boost overall output though, and how the horns interact with the room boundaries is another variable. I think getting the mouths closer to the front wall is the right move, but I'd be reluctant to fire them into the center of the room because this will result in symmetric side-wall reflections that combine to create a deeper null along the center line of the room. Why not fire them into the side walls? This will minimize distance between the mouths and the most rigid boundaries. If smoother side-to-side positional response is desired, the horns could also be placed firing into the front wall in two-high stacks in a 4x1 configuration. Of course if the real goal is to get more extension, maybe he should just *upgrade* to Skhorn's which can be tuned a bit lower at the expense of some output. :)
  14. SME

    Sundown ZV4 18D2 - sealed enclosure

    Any boost you do sacrifices headroom, and if you boost in the wrong place, you can end up making the bass more resonant / boomy. Take measurements at multiple locations in the room and avoid EQing (boost or cut) anything that is not consistent from seat-to-seat. The averaging feature in REW can be helpful here. Note that you shouldn't worry about EQ until you've optimized distances.
  15. SME

    Sundown ZV4 18D2 - sealed enclosure

    I recommend going with what measures best. Another option to consider is to put the other sub on the left at the rear of the room, as laid-out. That will likely give you the best deep bass performance. However, integrating with the mains is likely to be trickier. It might work OK though if you are using it with mid-bass horn(s) and/or the XO frequency is lower.
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