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Showing content with the highest reputation since 08/19/2018 in all areas

  1. 2 points
    I looked at the sim and it is quite close below 80Hz. This one should have less efficiency and less output above 40Hz on paper. It should have a bit more output near tuning. I'd say the original sims as being the slightly bit louder cab overall for music apps or live sound (kick drum, percussion fundamentals, most of the content being above 40Hz etc.). I've found over the years I like smoother responding wider bandwidth systems vs systems optimized for more sensitivity over a narrower band of operation. This is part of the reason I decided not to do a straight slot. I wanted extra upper bass output and extension well beyond 100Hz as part of the design goal. Often times you'll see guys using subs for 30-70Hz and another set of kick bins for 70-140Hz or whatever. Usually due to sub bins with degraded upper range behavior or just not enough output. I'm not a fan of that approach. I'd much rather have one cab that can handle everything. I think the sim you proposed would be fine. I tried to get the top end as extended as possible on this one. Another reason I didn't choose a large straight slot was to more fully enclose the drivers inside the cab. Most of the time I notice non harmonic mechanical and operational noises before HD gets to be offensive. The acoustic roll off of the slot above 100Hz should help lower HD a bit, but with the driver cone edge only 10" from the end of a large slot with line of sight to the outside world I'd expect there to be more operational noise leakage, though HR doesn't show too much of a difference. I'd like to see that tested actually. Also the drivers would be a little more susceptible to rain or a drink spill, but either arrangement is safer than a direct radiator cab! I didn't go with a push pull driver arrangement due to the minimum clearances needed for the drivers (10.5" driver depth + a large dustcap and +40mm excursion worst case scenario minus some for the baffle thicknesses and depth to the dustcap below the frame plane) and the fact that most high excursion sub drivers make quite a racket from the motor and suspension when pushed hard. Even more of a reason was the uneven loading it would present on the drivers. It would be much more involved and difficult to design the cab to evenly load the drivers with one inverted. Not impossible but it would complicate things. I'd give a rough guess that there would be about a 25-30L difference in the vented air volumes seen by the drivers. Tuning would be slightly different unless compensated for and the throat area would be a concern. I know this has been done in plenty of cabs before but I don't know if I trust it with the kinds of pressures that can be developed inside something like these. I didn't think the potential lowered even order distortion outweighed the concerns with uneven loading and possible mechanical noise from the inverted driver motor. The forces inside these can be pretty ridiculous. The force cancelling works really well on it. It's not like the drivers are 90deg rotated from each other or even 45deg. It's only a 12deg offset and it's a 250+ lb sub. In use the cab has no perceptible rocking from the driver operation. That small amount of offset from exact opposition plus the sheer size and mass just doesn't add up to any real rocking forces fore and aft. Technically I'd guess a perfect driver opposition would measure a bit lower with an accelerometer but in practice it worked like expected and it's a complete non issue. Regular old panel vibration and bracing is a much bigger concern. The Skhorn has been quite good as far as that is concerned when compared with most other large cabs, but this is always a battle on big subs with tons of output. About Edge and directivity. Keep in mind that the math is simplified and goes back to the point source mic placement method. If the radiating points are spread on one sub and focused on another you can never truly get the same mic distance from the two. In practice there is a very large area that one is trying to cover usually inside of a room with boundaries. It's complicated. One sub is more diffuse but that's not necessarily always a bad thing. Edge is a good tool but I don't get too caught up in an apparent half dB advantage here or there. Most of that directivity happens above 80Hz unless the baffle area starts getting truly large. One way I like to think about this is with 2 different philosophies. The first would be maximize the baffle area for the cabinet (think DTS-10 shape or similar) and get as much out in front of the cab with the drivers and design as possible. However at what point does this become impractical? Let's say the cab has a 60x60" baffle and is very shallow and gets some extra forward gain over a very similar design with the same driver which has a baffle of 30x30" but is much deeper. At some point you run into limitations in available depth to use and/or available baffle area. How many 60x60" baffle cabs are going to be able to be arranged? In a lot of cases not too many and eventually you just need more cabs and drivers. You could fit 4 of the 30x30 subs into the same baffle area as the 60x60 that would outperform it. The best case as far as potential output density per baffle area goes is that one entire face of the sub is radiating surface area. That's not going to be the best for directivity control though. You also end up with deeper cabs to get your cab volume. Tradeoffs. Vent area is vent area I'll give you that as an advantage for sure. This is the #1 priority I would have when redesigning the Skhorn. Mostly to work better with the lowered tunings. I try to avoid turns in vents when possible though. The reduced area of the slot for the drivers would increase air velocity over the horn expansion type though. I have some new thoughts on designing vented subs that I haven't gone to far with yet but I'll share once I think it through a bit more. Anyway that's part of the thinking behind not doing the straight slot or push pull drivers originally. It all comes down to tradeoffs and design choices. None of it is black and white it's all grey area and what makes sense for each case.
  2. 1 point
    Here on earth, and elsewhere in real life, physics do actually follow those generally accepted rules. Big objects no longer supported fall down, and in the process makes a lot of sound, and the bigger the object, the more low frequency energy it creates. Because there is gravity, and there is air. Like when this glacier brakes loose a quite significant piece of ice (see below for appropriate BEQ): This clip has decent sound, only 2 channels obviously, and it rolls of around 30hz, most likely due to the mic+recorder. A BEQ something like this restores enough to get an idea of what this was: sfm 22hz q=1.4 gain=+12dB sfm 14hz q=1.4 gain=+8dB If you expand to 5.1 you get more headroom and can retrieve even more below 10hz, by moving the low frequencies to LFE.
  3. 1 point
    Wait... what? I thought that any object travelling on a specific course in space would continue unabated unless an external force acts on it? (Isn't that one of Newton's laws? Or Einstein's? I kind of missed a few Physics lessons at school due to discovering the local club / a girlfriend / alcohol... lol)
  4. 1 point
    Moar!!, I used measured driver specs with complex inductance parameters. I have them so those are what I use. Of course there is correlation between harmonic distortion and large spikes in response. This is a well known phenomenon affecting any speaker (vented resonances for example). In this case the 3rd harmonic isn't high enough to worry about. The second harmonic accounts for nearly all the THD 100-120Hz but it doesn't break 10% until it is producing 134-135dB at 2m outdoor ground-plane which is extremely loud. A typical low pass filter would decrease the output and power demands in that range quite a bit. I've not noticed it in use. Low pass filtering does increase delay. However with less low pass filtering slope your putting more power into the cab at higher frequencies. The same holds true at lower frequencies as well. I think the issue with many of the worst sounding bandpasses or higher order cabs is that as designed the bandwidth is extremely narrow, perhaps an octave or an octave and a half and they have ringing and other energy storage issues. You end up with what is described as the one note sound. Then you throw the filtering and other EQ on top of that and you end up with a smeared mess before you ever put them into a room, which further makes a huge mess. I've tried very hard with the Othorn and Skhorn to make subs that have an extended & smooth response over a large range and that have very well damped behavior. They are not as absolutely loud as they could be because of it. However I think the tradeoff is worth it because they sound nothing like the typical higher order cabs I've had experience with. I think a lot of others would agree. When I say "room" in this context I don't mean someone's living room. I mean everything from a church to a night club to an auditorium to a theater to a huge arena. Most of the time subs will not be operating outdoors or in a huge stadium or arena, but will be in some sort of small / medium venue. These are still rooms with boundaries. In a lot of cases the subs will be back up against a back wall or corner, under a stage, flanking the stage, part of the stage even, flown up near the ceiling, ground stacked etc. There's a lot of variation. Vents and maximizing output at the low frequency corner...If you assume that we have enough upper and middle range output and efficiency and need the most output at the tuning area and follow this thought process you will end up with direct radiating vented subs. They will always have maximal use of cabinet volume for the vented chamber and maximum vent area versus an alignment which loads the front of the drivers. It should also be simpler. Assuming you keep the cabs the same total size of course. I thought the advantages of this alignment overall outweighed the slight loss in maximum output near the tuning frequency and the extra build complexity. If you want maximum vent loading and output near tune go standard vented. ELC and is a whole other area of discussion that should probably be handled elsewhere. It's a study of how our hearing perception works not how we should be hearing things. We don't need to correct for it. 30Hz is not supposed to sound as loud as 500Hz. It's been covered in some good discussions on other forums like AVS and DIYaudio.
  5. 1 point
    Me thinks you’ll fit in just fine here. Welcome.
  6. 1 point
    Just keep in mind, if you want to use any of the BEQs that don't list S, you'll need to convert Q to S. I recommend Excel to do the grunt work. There's a bit of discussion about that earlier in this thread:
  7. 1 point
    Now I have watched half of it, and the impression of the sound is even better than the first brief screenings. ULF is well done, and it sounds much cleaner and less distorted than other movies with clipping and heavy limiter use. I used to believe that a spacecraft that runs out of fuel will just continue at same, constant speed in same direction, but you always learn something new, from watching this movie it is obvious they loose speed and eventually go to a halt.
  8. 1 point
  9. 1 point
    Oh I see, that's great news. Cheers for explaining that to me biga6761.
  10. 1 point
    Thanks Max for all your amazing continued work in this thread sir. All of your corrections have made astonishing differences in all these tracks in this thread, some of course better than others but that is totally mix dependent and has zip to do with your glorious work. The most recent correction for RP1 did wonders. This mix was already solid compared to the recent rash from Disney but the correction makes this a Demo worthy track for sure. This track and AQP are in line for my favorite mixes of the year so far. Thanks again Max and everyone else who has contributed , I look forward to all the future corrections you have time to put together and check this thread almost daily.
  11. 1 point
    I have 21DS115 on it. went with 8ohms, thinking my inuke would blow up with 2ohm loads. It's ugly now, but it will be painted and speakon-ed.. Just couldn't wait to fire it up. Wife is told it's only the left side, I need one for the right side. After her jaw dropped, she just said, OK sell your other speakers and you can build another sub. Wohooo
  12. 1 point
    Ready Player One - Dolby ATMOS (7.1 bed measured) Level - 5 Stars (112.67dB composite) <=NOTE that this is with dialnorm REMOVED=> Extension - 3 Stars (16Hz) Dynamics - 5 Stars (29.53dB Execution - TBD Notes - Clipped but decent soundtrack to accompany terrific visuals. I still do not have overheads, but my surrounds are mounted high and some overhead effects were experienced. Possible BEQ for this one. JSS
  13. 1 point
    It's painfully obvious, especially after all this time and with a strong consensus in the community.... that there is not a technical limitation in play but rather a creative one. These start out as crummy mixes outright and they stay that way all the way to home video. So at least they are consistent.... consistently average at best.
  14. 1 point
    I got myself a Powersoft K20 for these and tested them at full power for 20 hours,the amount of power and the stability that amp has is way way higher than what the clone or the Crown could ever dream off. I set the limiters and processing and I installed them in a small club for further long term tests. The deep end is imense. I have a pair of xoc1 TH18, we got 2 Vs 2 with their own processing and limiters on a K10 and the 2 large SKHorn got +10 dB on a 2 minutes average pink noise dBz and +18 dB at 30 Hz .
  15. 1 point
    One of those looks quite a bit better as a subwoofer to me.
  16. 1 point
  17. 1 point
    This doesn't solve the phase match problem. If one uses a textbook electrical LR4, then the phase shift of the high pass and low pass filter will be identical vs. frequency. However, unless the speaker and sub(s) are ruler flat throughout the crossover region and co-located, they likely won't be phase-matched to begin with. The THX crossover was developed assuming the mains were sealed and had a natural Qtc=0.707 (Butterworth) 2nd roll-off. Two cascaded 2nd-order Butterworths makes an LR4, so the THX crossover applied a single 2nd order Butterworth to the mains and a full LR4 LPF to the subs. Provided that the subs didn't roll-off anywhere within the crossover region, that the mains behaved precisely as specified, and that they were co-located such that room effects applied to each equally, the result was ideal. In reality of course, "bass management" is a stinking mess. The whole point of it was that one could put the subs somewhere better for sub bass, but often the "better" locations are not so good for integrating with mains, especially where multi-listener is a priority. And of course, very few mains are sealed with perfect Qtc 0.707 and Fb 80 Hz. Any significant deviations from there substantially influence the phase response in the critical crossover region. Most mains these days are ported and tuned well below 80 Hz, so they have only slight phase shift at that point. They would do better with a full LR4 HPF, but few AVRs / processors seem to offer more than one XO type. My Denon AVR has the THX 2nd order 0.707 HPF baked in, which totally destroys the bass-managed mid-bass response with any speakers I've owned. The LFE response may measure picture perfect, but the mid-bass response of the other channels looks like trash. Also, how many subs are actually flat through the XO? Most of the beefier drivers are already dropping off from inductance effects. Sad to say, home theater "technology" is still stuck in the 90s in many respects. Great sound pretty much requires extensive customization, as I've learned over the years, and the affordable options for doing so leave a lot to be desired.
  18. 1 point
    To be 100% clear, I absolutely recommend highpassing horns due to their out-of-band distortion performance.
  19. 1 point
    Othorn files. OTHORN print AUTOCAD 2000.DXF OTHORN DXF scale print.pdf
  20. 1 point
    I don't think it's fair to characterise those threads as maximum vibration chasing. Obviously there are some people who do that, just as there are people who chase extreme SPL, but mostly it's about finding out how it responds & what feels right/good. There seems a lot of variation on that point, or more specifically, the way people describe what they like seems to vary a lot. It's all about balance in the end.
  21. 1 point
    Yesterday was the day. Spent about 12hrs testing the Ipal loaded version in every configuration with the SP6000 amp and the K20. It's capable and after the equivalent of 6 full tests back to back, I can say it won't be easy to blow one. It's going to take a while to get through all of the information in detail.
  22. 1 point
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  24. 1 point
    Sin City and AvP already measured. The 2nd Sherlock Holmes was a huge disappointment compared to the first. Robocop will not measure well, just like most films in the 80s. Remember, THX was the FIRST to spec a subwoofer that could dig to 40Hz. Before that, only Sensurround dug lower than 50-60Hz, and only for a bandwidth limited noise 'rumble' effect. THX was first implemented in 1983, with Return of the Jedi. It took time to get the bass out there. Digital did more to expand the bandwidth than anything else, as all analog technologies were highpassed (to avoid wow/flutter/LF noise and to preserve headroom) and the old Dolby Digital and DTS theater mixes were essentially equal in quality to what you could get on DVD (using the space between sprocket holes to encode the 5.1 soundtrack), but they were the best thing since sliced bread (remember the Dolby Digital Train trailer in theaters)?. Once dependence on the celluloid material itself was eclipsed (DTS was the pioneer in this, with the sync'ed CD player), true ULF could be encoded. Now with digital projection, the only limitation is the audio playback system. The foundation is there. Before, it wasn't. I know people get pissed when they see a blockbuster have the shelf filter profile. But if you can't monitor the ULF, and the director/boss says 'LOUDER', then to avoid clipping the hell out of the track, you simply shelve off the ULF. Instant 'headroom'. You can then turn up the track louder, and compress it further until the director/boss gives the 'thumbs up'.....for all the grief we have given sound designers/editors/mixers, the directors are the ones which we should be complaining to, unless the studio execs are telling the directors what 'needs to happen'.....they are the final givers of the thumbs up. JSS
  25. 1 point
    The A-Team (5.1 DTS-HD MA) Level - 2 Stars (106.9dB composite) Extension - 5 Stars (1Hz) Dynamics - 4 Stars (26.04dB) Execution - 3 Stars (by poll) Overall - 3.5 Stars Recommendation - Buy (by poll) PvA: