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Showing content with the highest reputation since 08/07/2019 in Posts

  1. 6 points
    Ok... report after 3 full days of Skram use. Josh, thank you for this amazing design! I am simply blown away that this kind of performance can be had through diy designs, you are doing the music world a huge service with your knowledge and plans! I do feel I need to apologize if I created any doubt in my previous posts about the low frequency output of these things.... a stack of 4 center clustered with all the mouths centered to each other create just a crazy amount of output, they blur your vision and make your voice change haha! After the feedback from earlier discussions I added some parametric eq to flatten the the raw response (thanks SME) and they really seemed to respond well to that. They still retained the incredible kick and midbass impact while also having literal giggle inducing deep gobs of sub bass output. They are just so incredibly clean and powerful no matter what you put into them, just stunning really. Following some recommendations in another thread I had my limiters set as per the recommendations for 45 volts / 500 watts during bass music acts and lowered it to about 35 volts or 300 watts during our techno and psytrance acts. I never needed to run them up to these limits, they provided tons of output to easily keep up with my sh-46's. The combination of the skrams and danleys is just amazing, I couldn't be happier. I didn't take any videos myself as I was running my ass off all weekend, but a friend shared this iphone video with me. Ben Rama from Techgnosis records playing some super minimal atmospheric tech trance. If you listen with headphones you can get a sense of how powerful and clean the dynamics of the skrams are. Kick drums and bass feel immense, and clean clean clean. Video taken at about 150 feet from our visuals booth. And a pic of the set up https://i.imgur.com/IGh2BDp.jpg
  2. 4 points
    It's hard to believe, but I've finished my subwoofer - global pandemic be damned. It seems like it took forever, but at some point you just have to stop. Painting the box the way I did greatly increased the time it took. Leaving it square & painting it with truck bed liner would've saved me weeks. No matter now. Here's the finished box. Just so someone will know I painted the bottom the same way... here's the bottom. Because I have a dual 2 ohm voice coil driver, I wired it in series. I ran one wire to connect the negative of one coil & the positive of the other voice coil. Then the internal wire was split with the positive to one coil & the negative to the other. My concern over getting the driver positioned correctly so I could get the screws through the holes in the baffle was unnecessary. With only a slight bit of adjustment the screws lined up & the driver was tightened into place. Sliding the ports in & attaching them with 4 screws was even easier. Voila! I couldn't let a comparison with my former 100 watt 12" Polk sub be overlooked. I took a picture of my entertainment center with the Polk sub in place. Now with my new SI SQL15 sub with a 1100 watt Crown amp - with & without speaker grill: It sounds absolutely wonderful, but I don't have a microphone I can use to give you any kind of performance data. I'll get to that soon. But I want to thank all the people who helped me get through this process - especially @dgage who helped me set up a visit with Nick at Stereo Integrity along with other good advice. Everyone was so gracious to this old man that I can hardly express the extent of my gratitude The picture of my MDF was taken on Jan 21. On June 5 I hooked it up & listened to it for the first time. Worth every minute.
  3. 3 points
    I will try to explain as best I can here. Shorting rings don't act mechanically, at least not directly. They magnetically interact with the voice coil to reduce and/or linearize inductance through the driver's stroke. The voice coil is a natural inductor. Inductors store and release energy via the magnetic field in their proximity. For a straight wire with pure resistance, the current responds in perfect lock-step to changes in voltage. If an inductor is subject to a sudden increase in voltage, however, some time and energy are required for the current to "spin up" the magnetic field. At that point, if the voltage is suddenly cut to zero then the current flow continues for some time while the magnetic field "spins down" and releases stored energy. Hence, rapid fluctuations in voltage tend to be smoothed out in current, e.g. high frequencies are reduced. This is a major cause of high frequency loss and sometimes "humping" in a speaker driver's response. At the same time, the inductance itself is likely to vary, not just with frequency but with changes in instantaneous current and/or driver stroke. This is *non-linear* behavior, which causes distortion, including inter-modulation distortion, which may be particularly undesirable. Though the linear aspects can also be degrading if not precisely corrected with EQ. The response "humping" alters the spectral balance and likely imparts a non-neutral characteristic sound. A shorting ring is made from a material that is both magnetically and electrically active. The magnetic field generated by the current induces current flow within the ring. The ring "shorts" this current to the rest of the driver assembly, allowing some of the energy in the magnetic field to be transferred to the shorting ring and dissipated as heat instead of stored. If designed correctly, this effectively reduces the inductance of the coil), and depending on the position of the rings vs. the voice coil, may also keep inductance from fluctuating as much throughout the stroke. The relationship between inductance and damping is via the electrical impedance. Impedance is essentially a 2-dimensional quantity which can be described in terms of a pair of parameters: either *magnitude* and *phase angle* or *real* (resistive) and *imaginary* (reactive). Inter-conversion is possible via basic trigonometry; see the "Complex plane". Damping is a property of the resistive / dissipative (non-energy storing) component of impedance. Pure inductance and capacitance both contribute only to the reactive (energy storing) component of impedance. Speakers using a composite electrical circuit that has effective resistances, inductances, and capacitance contributed by several different factors including the mechanical and acoustic properties of the system. So needless to say, inductance and "damping factor" both contribute to the system behavior in a way that's not simple to describe. To answer your last question: No. I mean, if the resistance of your speaker wire is high enough be a problem in the absence of shorting rings, then shorting rings probably won't fix that problem.
  4. 3 points
    The CKRAM is a compact, single 21" subwoofer, that is designed to be flexible enough to suit a variety of applications, but is primarily intended for sound reinforcement or Pro use. Dimensions: (24" / 610mm) Width x (30" / 762mm) Height x (28" / 711mm) Depth Drivers: Most of the good pro audio 21" drivers will work well in this cab. The Lavoce SAN214.50 is a good budget option. The Eminence NSW6021-6 is what the CKRAM was designed with during modeling. It or the B&C 21Ipal are top tier options. Other drivers that should work well include 18 Sound 21NLW9601, 21ID, B&C 21SW152, 21DS115, etc... Design: The CKRAM is a hybrid 6th order design in some ways similar to the SKHORN and SKRAM designs but notably different in others. The CKRAM has a multi-port back section which allows for adjustment of the port tuning to suite the application. The front section is in effect an extremely short, symmetric, horn/slot/small vented chamber. The front assembly is intended to be removable and the CKRAM can also be operated in a standard vented alignment. Vent Tunings: Note that the CKRAM can be operated in 6th order or standard vented operation. In either case the vent tunings remain the same. All vents open = 30Hz 3 vents open = 25Hz 2 vents open = 21Hz 1 vent open = 15Hz Horn Response Models: These should be close. The inputs for each vent configuration are included. The match is quite close to a much more detailed Akabak model. Use the semi inductance specs for the driver you are simulating! NSW6021-6 semi inductance This is the Akabak script if anyone wants to dive that deep. ckcomplx.aks
  5. 3 points
    It's my dad's and my shop, yes. The biggest benefit is that my recording studio and my equipment storage area are in the same building. Plus everything is well isolated (acoustically) so that I can work way past midnight without anybody caring. The CNC was the latest addition to the shop last summer and it has easily been the most used machine in the room ever since 😊 It may look spacious, but it really isn't. There are machines everywhere!
  6. 3 points
    Hi Everyone, I have taken @dsl1 files from page 15, edited them to test the fitment of everything on my laser scaled for 5mm and 3mm thick birch ply. I have made a few minor adjustments so far and created a good assembly test setup 6.5" wide, 10" tall and 9" deep. I have ordered the handles, T-nuts and Duratex from Parts-Express. I have to say I really like the updated design that eliminates all of the multiple bracing pieces in the original design files and combines them into larger single pieces for faster assembly. I plan on changing some of the joints on my files so that the edges interlock when I do go to V-Carve and CNC cut the full size design. I also plan on adding a piece that covers all of the front ports for storage so no critters get in and make a mess. Once my scaled files are done for the 3mm and 5mm birch I will share the illustrator and dxf files so anyone can make a mini box if they would like to as well. I like physically handling the box at this scale, it helps me visualize the assembly and work through any kinks.
  7. 3 points
    So by request, the comparison of DVD vs BD LOTR Extended Edition. I remember graphing them a few years ago, but with the LF content thread request, I dug a little deeper. Here is the comparo between DVD and BD Fellowship of the Ring: The DVD has the green Peak and red Avg graph, the BluRay the cyan Peak and the green Avg graph. Stats for the DVD mix: DC offset -0.000046 Min level -0.663155 Max level 0.593566 Pk lev dB -3.57 RMS lev dB -32.86 RMS Pk dB -10.99 RMS Tr dB -119.97 Crest factor 29.15 Flat factor 0.00 Pk count 2 Bit-depth 24/24 Num samples 657M Length s 13686.741 Scale max 1.000000 Window s 0.125 The DVD clips in 12 locations across all 7 channels, mainly in the Right Surround channel. Stats for the BD mix: DC offset -0.000048 Min level -0.629489 Max level 0.594391 Pk lev dB -4.02 RMS lev dB -33.07 RMS Pk dB -11.22 RMS Tr dB -234.33 Crest factor 28.36 Flat factor 0.00 Pk count 2 Bit-depth 24/24 Num samples 657M Length s 13697.685 Scale max 1.000000 Window s 0.125 The BD clips in only 2 locations across all 7 channels. The tracks differ only about 1/2dB all around, including only 1/4dB difference in dynamics. They appear to be very similar, likely the same track save for some minor differences when putting the whole thing together. Given SME's prior remarks, and the BD's lack of clipping, I think the BD is the track to get since it is lossless and may contain more HF content compression may take away. Looking at every channel's PvA, it is quite obvious why this track is held in high regard for LF content. ALL the LCRS channels extend to nearly 5Hz. This track may be amenable to BEQ. The Two Towers and Return of the King as I have time. JSS
  8. 3 points
    Hope everything is good with you Luke. Good luck with the sale.
  9. 3 points
    I see it's been about two years since my last update. My hardware configuration hasn't really changed in that time. I still have all the drivers I was going to use to build new MBMs, but I'm now not even sure I need them. Building them is a very low priority, and the amp I bought to power them is likely to get used to power my "demo" speaker system instead. OTOH, the DSP configuration has been modified heavily. In other threads here, I've hinted about my discovery of a novel method for optimizing low frequencies. I've made substantial progress on this and also on optimizing high frequencies, which seemed to benefit from more attention after I'd managed to drastically reduce the muddying effect of low frequency problems. Lately, my attention has returned to low frequencies, this time dealing with sensitivity to physical /environmental changes such as the precise location of MBMs and absorber panels vs. where they were when I measured. Just this week, I finally implemented the first algorithmically optimized low frequency configuration. I expected some improvement below 40 Hz, but was amazed by how much the increase in precision provided by computer vs. hand optimization improved the sound from the mid-range on down to the very bottom. I watched some of the scenes from "Ready: Player One" using the @maxmercy BEQ. It's hard to describe the experience. Despite pushing into the 120s dB, the bass never trampled the mids and highs, which came through clearly even on the weightiest of sound effects, yet the bass itself contributed intense physicality to some of the sounds. The slam was impressive, not just because it was there but because it was *everywhere* and in a wide variety of different flavors rather than being a one-note-ish thump as is often the case with PA systems. I also didn't notice any house shaking at all, but I don't know if this will be the case with other movies. As a kind of ironic conclusion to this thread, I figured out that I didn't need 4 MBMs with independent DSP to get "perfect bass response" at all my seats, yet the title seems to be a reasonable description of what I experience now with my optimized configuration. What I mean is that the bass almost feels like it's coming from inside my own body, and this sensation follows me around the room, even when I'm well outside the "calibrated" listening area. This is similar to experiences I've had with superb quality bass systems outdoors, but I'm experiencing this indoors throughout a room that's not especially large nor heavily outfitted with absorption. The low frequency sound in general seems to be completely untainted by the room, and the acoustics of the recordings (whether natural or synthetic) come through with remarkable clarity. Unlike those outdoor systems, I am able to take full advantage of room gain and hit high SPL down to much lower frequencies. Part of the reason I became so quiet about my recent work on my system is that I am seriously thinking about seeking commercial application for my technology. My confidence in this regard has been growing over the last year or so. I'm now fairly confident (i.e. > 50% chance) that I will go into business, in some form or another, with this technology. I haven't worked out the details yet, but I have some ideas. I'm likely to start small with custom / bespoke installs. These could be for ultra high-end home theater or perhaps for mixing / mastering rooms. These early jobs could fund further research into adapting my methods (or developing new ones, where necessary) for cars as well as potentially larger rooms (cinemas?) and outdoor environments. Admittedly, I'm shying away from doing any kind of consumer product because I don't know if I will be able to make my tech work reliably under those circumstances. I don't know if I can really make it "idiot proof" enough, but I can potentially research that too. So with that said, I'll try not to self-advertise too much in these threads. Thus far, I haven't really meant to. I'm just passionate about this subject and am having a very hard time "keeping this great sound to myself". Maybe I should just record my system and post it on YouTube? () Seriously though, from a marketing standpoint I've already lost. Just about everything positive I'd like to claim about my own sound has already been claimed repeatedly for other products that, IMO, don't live up to the hype. So perhaps my best approach is just not to *say* anything and let my systems "speak" for me. That probably means starting small and growing very slowly, which isn't necessarily bad.
  10. 3 points
  11. 3 points
    Na, they are in our studio with the big Danleys. Had about a dozen friends over last night for a listening party with the new Tool Album. Holy shit! I am continually blown away with these Skram subs. Danny Carey's drums sounded so immense! kick drums right in the soul haha! In all seriousness we collectively agreed that none of us have ever heard kick drums sound this good out of a soundsystem. Made for a super memorable night, fuck going to concerts lol!
  12. 3 points
    Avengers: Endgame (Dolby ATMOS 7.1 channel bed) Level: 4 Stars (110.9dB composite) Extension: 3 Stars (16Hz) Dynamics: 5 Stars (29.44dB) Execution: TBD Overall: TBD Notes: the DTS 7.1 track is not as dynamic as the ATMOS track. JSS
  13. 2 points
    I did. The old 7560's which I believe were the same as the Crown M600 and a couple of other re-badges. It's been a long time but it was something like 1500w burst into 4 ohm and 1000w for a very long time and would do it at 20Hz. Doesn't seem like much these days. These aren't really amplifiers intended for "music" signals. These are industrial grade equipment for labs, measurements, running motors, MRI's, etc. HEAVY loads. They do audio just fine but are WAY overkill for bumping some music. Kinda like taking a Mack tri-axle dump truck to pick up 100lbs of mulch. I love how they rate their amps and provide all of the engineering specs. Compare their data sheets to those for Behringer or Yamaha amps. This is how gear used to be spec'd. I wish it still was. Amps really should be rated in terms of voltage and current capability into various loads at different frequencies IMHO. A 7810 or 7796 is a monster power source even if some 20lb amps produce more power on paper. The ratings are MUCH different. Yes they are heavy as hell. They have to be. You'll never get this type of ruggedness and sustained power output out of a 20lb amp. If I was filthy rich I'd have a stack of these installed on 3 phase to run the subs, just because.
  14. 2 points
    Thought I should update this thread as I went ahead and built a pair of VBSS subs to live with my Danleys. The hype is real, these are fantastic sounding subs considering their inexpensive cost to build. They wont crack the stucco on my ceiling like the Skrams did, but for listening to music at moderately loud listening levels I couldn't have wished for a better outcome. Thanks for the help everyone, the project was a success! And I didn't blow a bunch of money I didn't need to spend in these strange times. Aesthetically I think they make for a great match with the Danley's as well. https://imgur.com/gallery/R1JSs05
  15. 2 points
    The 1kv to ground sounds very weird as even if the heatsink was live on purpose you wouldn't expect 1kV to be generated anywhere in the amp. Mix of output transistors is a very bad idea as they won't share current effectively. On the plus side this is making me very certain I don't want one of these amps in my life
  16. 2 points
    Small update from my side: I was very eager on posting results here but the blown amp has demotivated me to the part that I went on to finish other projects first. So now I have a vacuum hold down on my CNC. And about the broken amp, the replacement power input board arrived and it blew up as well. Means the PSU is broken, which will run me about 300$ probably. Good thing is that I've watched a movie with one of the spare amps I had in the store and the clip lights didn't even light up once. I didn't change the settings and volume matched everything properly. Means I can now run the quieter amp (fan noise) with much lower idle power draw without any performance penalties. The spare amp does like 2000W total, which is fine with the SKHorn as efficient bass maker and the BOSS platform as efficient TR maker. Now that I think back about the times that I had the bridged clone amp on the SKHorn and this bridged amp on the TR I realize how overkill it was. I watch my movies at -10MV with the EQ at +15db at 20Hz. No dynamic EQ. Will post the first test results some time next week I guess, I will add different frequency tests when I have the time to do those.
  17. 2 points
    @kipman725 Interesting concept, I guess you're going into a similar direction as what current high power PFC amps are doing? I like the trend of new amps to come with a universal power supply. The new Powersoft amps work with any input voltage from 70-270V iirc, single bi and triple phase. Fully equipped with PFC, relatively high efficiency and the option to set a breaker in the dsp. As I see it, only increasing efficiency and stored energy will allow for more output with high crest factor content. And yea on the amp, it was my main HT amp. I swapped it for one of my spare amps and lost ~8db headroom. The SKHorn is efficient in the upper register and room gain of my small room helps with the lower end of the spectrum, so the single sub I'm running will probable be fine. Gramps is currently investigating the remains of the amp to check for bad parts. I'll swap out the entire broke board and see if I get it running again. If that doesn't do it I'll see what if would cost to swap the entire PSU. I suspect the mains relais to be the point of failure, which would be an easy fix. @klipsch I've read about it blowing up. notnyt is actually the guy who sold me the Pmillet Soundcard Interface, which I'm using for my tests 🙂 @Ricci I had it on a C16 breaker, which tripped after 14s. When I hooked it up for 32A230V it blew up... The clone muted its output (DC protection) a few ms into the 1Ohm test. Maximum it did was 3.5KW for half a cycle. It also muted the output when I set my test frequency to 10khz instead of 1khz accidentally. I do all tests with a 1khz sine wave. "If the amp can do 10 cycles at 1khz it can do 1 cycle at 100Hz" is my logic, so the 1khz test allowed for a 1ms "resolution". I will publish the results as seen below. The graph below is the first I've finished. @SME I evaluated the results of the Sanway amp and noticed that the 2Ohm power sustained for 260ms, not 80. 260ms is very nice imo. Idk what it would look like with both channels driven, since I couldn't test that anymore. The graph stops at 13.3s, because the breaker tripped. I won't test the amp again on a 32A circuit, even if I get it working again. I tried to do all tests at a total duration of 2 minutes, but out of the 4 amps I tested this way one was fine, one started smoking, one started smelling and the clone blew up. What would you guys suggest? Is 2 minutes too long? Not useful info anyways? Not all amps have superior safety mechanisms built in like maybe a Powersoft amp does... I had a look at Martin Garrix's "Animals", which is a pretty bass intensive song. The longest duration of more or less uninterrupted bass was 28 seconds with a pretty low crest factor. Even most heavy bass dubstep songs have something that resembles a chorus and quieter sections in between, so I think a 30s sine wave test should cover most of it. I'm not in the situation yet where I can afford to blow up half of my amps because I want to test them at their absolute limits. I'm hoping to have a write up on my testing methodology posted after the weekend and maybe some final results already.
  18. 2 points
    The Loadbank While a bucket might've been the easiest solution, I wanted something rack mounted (for easy storage) that at least somewhat resembled something store-bought. I figured I could fit everything into 3 rack spaces, so I bought a 3U case from Amazon. As with everything I do, I first made a 3D model in Inventor. That always proved to leave very little room for errors. This is the front plate I made: After I was happy with the design, I generated some G-Code with Inventor HSM and made the front plate on my cnc router. I used a 2mm end mill to cut the holes. I have since bought a 3mm end mill specifically for sheet metal, which is much better suited for the task obviously, but the results were decent nontheless. For the hardware I used regular Neutrik connectors, heavy duty (30A) switches and busbars for easy wiring. I glued the busbars to the front plate. The heavy gauge wires were a pain to solder with my tiny soldering iron... I have 12 heating elements with the blue cap on the back and 4 without (went out of stock). The elements without the cap have a slightly lower impedance (~0.4 Ohm less). I cut a hole into the rear case wall and made a mounting bracket for the heating elements with some acrylic. The plan was to screw the elements into the acrylic (has been tested with scrap pieces before) but that didn't work out and I didn't want to try myself out on thread milling just yet. I used my favourite stepped drill bit to make the holes a little larger and glued in the elements that wouldn't fit with silicone. Everything else came together nicely. A quick sanity-check revealed that everything works as intended, which was a small surprise to me because I did all the wiring from the back of my head without a wiring diagram. With the current setup I can do 4x8, 4x4, 2x2 and 1x1. And of course various useless impedance combinations. The device is quite heavy fully assembled. I haven't weighed it yet, but it's probably around 40lbs. And it's sturdy. This is what the back looks like now: At first I thought I could get away with air cooling, but after one of those elements almost exploded into my face after plugging it into the wall in free air, I decided to go with a basic water bin. I still have lots of spare acrylic, which came in handy here. I trimmed the edges with a flush trim bit and even made a roundover. I never planned on doing any experiments with hot-forming or welding. The glue I used basically welds plastics anyways. The container was made to slide into the case. You basically fill it up with water (to the point I marked to avoid overflow) and put the loadbank over it. The loadbank then rests on the container, with the heating elements being surrounded by at least an inch of water at all sides. The case has enough room to accomodate the container as well. Without water preferably when stowing it... That about wraps up my build, which I'm pretty satisfied with. I tested one amp already and it worked like a charm. The banana sockets are connections for my Pmillet Soundcard Interface (or basically any oscilloscope). The font I used for the text on the front plate is called Elixia!
  19. 2 points
    Finally! Measurements coming soon. If the weather is on my side.
  20. 2 points
    Just a quick update. I have attached the front baffle, so all of the construction is over. Here's a pic of the completed box with the grill frame attached by magnets. It was at this point that serious sanding began. I decided to take the edge off of the sharp edges of the corners. I used a sanding block to "blunt" those edges. After a lot of work I had barely changed the shape of the corners. I knew after I used a router once that I would not be able to use a router indoors - the blizzard of dust would ruin my house. I realized that using a round-over bit once the box was built was out of the question. My wife & I are not able to pick up the box & take it to the carport to mitigate the dust in my house - remember, I'm 69 & my wife is 70. I have no idea how much this box weighs, but I guess it's easily over 125 lbs. I had never used a plane while working with MDF (hell, I've never sanded this much either), but I decided to give it a try - starting on the bottom of the sub in order to "hide" any screw-ups. I liked the early results so I continued to the rest of the box. I'm pretty happy with the results so far. Some more sanding to go before I start applying oil-based primer. I took the sub off of the saw horses because I need to roll it around to work on the various sides. Taking it off the saw horses was an exercise of "controlled fall." No damage to the sub, the room, and most importantly, no damage to me.
  21. 2 points
  22. 2 points
    I don't know much about particle velocity, except the basic fact that it causes compression at some point, and neither have I run compression sweeps of my cabs yet (waiting for better weather), but while looking at your hornresp parameters, I noticed that you haven't added the driver and front "chamber" volume anywhere. Normally you'd be using the driver's front air volume plus the small section with the thickness of the plywood you're using (was about 11000cc VTC with the IPALs iirc), but as to @Ricci's suggestion and my own comparisons with my finished cab, adding the driver's cross sectional area to S2 in horn resp results in a sim much closer to the real thing. For the 21" drivers you can add about 350cm² to S2 (driver+wood when back mounting).
  23. 2 points
    They are addicting! 2 is a nice start but 4 has a nice symmetry to it. 6 makes a good stacking height for your tops but is an odd number for amp channels.... better just make it 8 haha!
  24. 2 points
    Well, I finally got mine built! Lol took a while but life got in the way. I'm also just staring to do my fiber optic ceiling, so multiple things at once!. I should have the subs up and running next week. Drivers are DS115. Just getting duratex. Will be my nearfield subs lol.
  25. 2 points
    Installed behind screen. Hope to have them powered up this week. Unfortunately will have no time run any voltage to them this weekend 😫
  26. 2 points
    Hi Everyone, I have been following Data-Bass and the other forums for many years while building an art car. This year was its first year to the Playa after 4 years of work, a divorce, a child being born, etc etc. I teach illustrator, CNC Plasma, CNC Router, Laser and NFPA 160 Flame effects at a local makers space here in Truckee CA. I own a Boss Laser HP3655 Stainless Steel cutting 150Watt CO2 laser that I am using to make the art car with and helping other artists with their projects as well. This project is a labor of love and not for profit. http://www.instagram.com/jackalotus https://www.instagram.com/p/B2qSE1zhUI5/ https://www.instagram.com/p/B2ISZPCBKgp/ I currently have in mind building my own cabinets using two 21SW152's I currently own. I have been working on ported box designs for quite some time, but keep drooling over Ricci's awesome work on various forums going back to I think 2010. I plan on building tops with help from a Electrical engineer friend who works at Meyers Sound. I have a stack of Baltic Birch sitting here in my garage waiting for the right design to build around my 21SW152's and I think I have decided to throw my ported designs in the waste basket and go with the SKRAM design of Ricci's that everyone here is building. I plan on placing 2 of these boxes under the head of the PlayaPachederm. My Question is... Is anyone willing to share/sell an Autodesk file or VCARVE file? Also wondering how i can donate to all the hard work Ricci put in for us? Need anything laser cut out of stainless let me know
  27. 2 points
    Notes and free-air specs for these gigantic 24" drivers have been posted under the driver page. These weigh in at a back straining 115lbs and are capable of 4" peak to peak. Beef it's what's for dinner
  28. 2 points
    I doubt it. Psytrance needs a lot of power and control in the kick and midbass range and the skrams deliver it without breaking a sweat. Mind you the sh46’s pack a wallop themselves, matched up with the skrams its a potent combination. I’ve been in front of enough f1 and turbosound systems that really excel at reproducing psytrance transients and my system doesn’t leave me wanting at all. These Danleys continually blow me a away, I have no doubt Tom borrowed tech from recovered alien space craft 😂. I have a stack of 6 reconditioned Martin Audio b115 front loaded horn kick bins as well, next summer I’ll give them a go between the Danleys and Skrams just to see what happens
  29. 2 points
    Set up pic from our Halloween cabaret last night. Experimented with a 100hz crossover and found it to be the most impactful and cleanest config I’ve tried yet. Techno and psytrance all night, sounded incredible. https://imgur.com/gallery/qrU6jyD https://imgur.com/a/dacbWrI
  30. 2 points
    Droogne I've done square ports before and they work well. The ideal is round and heavily flared or shaped which I've also done where it makes sense. Have you read the available AES and other papers on ports? There are many. Compression and chuffing noise do not necessarily correlate. There are also papers which point to some possible advantages with multiple smaller vents despite the increased skin effect. In the case of the Skhorn and Skram variable tuning is an integral part of the design that I considered fundamental. That is why they have many smaller vents instead of a larger single. Also it is structurally very strong. When considering them as individual smaller vents they are not too far from square. Its all about the tradeoffs. I think you may be overestimating the effect a change to the shape may have on compression. A single square or even round vent the area of one of the Skhorn vents isn't going to gain much. They will still overload and compress. The area is not enough to cope with the demand once the sub is pushed at tuning. This is true of almost every sub tuned under 20Hz. In the Skhorn's native tuning with all vents open with 3X the vent area this isn't really an issue as the testing showed. At the end of the day it's all about vent area in my opinion.
  31. 2 points
    Finished a Skram a couple of weeks ago and I love the sound. My wife even commented on how smooth it sounded. Completely outran my tops. I originally put a driver from zxpc in it since the LaVoce was out of stock. Pretty ugly. Anyway got the LaVoce in and this is what I measured quick and dirty. No reference as to SPL - I used the USB OmniMic but I was running a signal flat from computer to mixer to xover. I think I lowpassed it at 200hz; high pass was off. Actually, not sure where I lowpassed it... somewhere above 100 hz. Also, I'm between jobs and would love to sell this to someone. Guess I should post it in the for sale section.
  32. 2 points
    Return of the King Extended Edition DVD vs BD: Very similar again, with the BD having slightly better dynamics and more clipping noted on the DVD version. DVD Stats: DC offset -0.000001 Min level -0.541110 Max level 0.589154 Pk lev dB -4.60 RMS lev dB -35.16 RMS Pk dB -10.58 RMS Tr dB -190.65 Crest factor 33.76 Flat factor 0.00 Pk count 2 Bit-depth 24/24 Num samples 758M Length s 15794.069 Scale max 1.000000 Window s 0.125 BD Stats: DC offset -0.000000 Min level -0.630937 Max level 0.592822 Pk lev dB -4.00 RMS lev dB -34.94 RMS Pk dB -10.14 RMS Tr dB -468.38 Crest factor 35.23 Flat factor 0.00 Pk count 2 Bit-depth 24/24 Num samples 758M Length s 15797.877 Scale max 1.000000 Window s 0.125 Crest Factors listed on all the stats are simple ratios of RMS vs peak amplitude, they are not in dB. This film has even more full bandwidth LCRS than the previous two films, with significant infrasonics in the back center channel (DVD and BD), and little roll-off in the LCRS save for under 10Hz. Basically, the DVD and BD presentations of these films are essentially the same. No tampering or shelving like we saw in 'Master and Commander'. JSS
  33. 2 points
    The Two Towers Extended Edition DVD vs BD: Again, virtually identical graphs. Clipping in this film is more prominent, especially in the LCR channels, both on DVD and BD, with more clipping in the DVD version. Stats for DVD: DC offset -0.000001 Min level -0.461359 Max level 0.464815 Pk lev dB -6.65 RMS lev dB -37.72 RMS Pk dB -14.70 RMS Tr dB -1.#J Crest factor 35.74 Flat factor 0.00 Pk count 2 Bit-depth 23/24 Num samples 678M Length s 14125.920 Scale max 1.000000 Window s 0.125 Stats for BD: DC offset -0.000000 Min level -0.521735 Max level 0.440078 Pk lev dB -5.65 RMS lev dB -37.58 RMS Pk dB -14.72 RMS Tr dB -143.65 Crest factor 39.49 Flat factor 0.00 Pk count 2 Bit-depth 24/24 Num samples 678M Length s 14131.499 Scale max 1.000000 Window s 0.125 Similar stats with slightly more dynamics on BD, but essentially the same track. This film had some strange filters applied to the LFE channel, and full bandwidth LCR channels, extending even deeper than FOTR. It is BEQ-able, with a possible pre-post: JSS
  34. 2 points
    Here is the requested comparison, I included the 5 most prominent drivers for this cab. It already looks like a small mess, which is why I didn't include more.
  35. 2 points
    Prelim BEQ for Fellowship: Lots of under 3Hz noise, hence the extra highpass down low, now I just need the time to screen it properly. These are long films. JSS
  36. 2 points
    This is a shot of the inside of the elbow before the other lengths were added. A few coats of Duratex with sanding in between make the surface fairly smooth.
  37. 2 points
    Let's see if this is enough to win the day today. It is a whole lot of win... Apparently it is
  38. 2 points
    Butterworth 24db filters at 80hz. Crest prolite 7.5 on the Danley sh-46 and powersoft k10 2 skrams per channel 2 ohms load
  39. 2 points
  40. 1 point
    @SMEI've been looking into getting a miniDSP to better fine tune my sub, so your recommendation for a HPF to protect the driver will move that decision along. I have a tone generating app that I used to do the test you suggested to find the tuning frequency. It appeared to be about 21-22Hz. By 18Hz the cone was moving quite a bit again. I was shooting for 20Hz, so it will be interesting to see what it actually is, when I do measurements with REW. Listening impressions - During the build I tried to give my wife an idea of what to expect from the new sub. It was always a difficult topic, because I wasn't completely sure what to expect. But now that it's playing in my living room, the new sounds I'm hearing are a little easier to describe. Both music & movies are dramatically different. With music there is a "presence" of bass that can't be ignored. It's not totally volume, but rather how the bass now seems to fill the room. As the bass line gets lower there is no obvious reduction of volume which, of course, makes it louder in the lower frequency ranges & that increase in volume comes with an increase in chest-thumping vibrations. Listening to music is a much more visceral, immersive experience now. Even at moderate volume the ability of the sub to reach down & hit the lowest notes with authority is impressive. Movie viewing has been radically changed - especially action movies with Dolby Atmos soundtracks. However refined & musical it's capable of being, start Mad Max Fury Road & it becomes a sledgehammer - seriously rocking us during explosions. The ability to reproduce loud explosions, gunshots or car crashes is stunning. The sub never seems to be pushed anywhere near its limits - even when the soundtrack is as loud as I can stand (the ultimate measurement of the volume capability of your system - it's louder than you can listen to it) . I don't want to sound too giddy, but I'm more than pleased - I'm thrilled.
  41. 1 point
  42. 1 point
    I just skimmed this thread trying to catch up on everything I've missed in the last couple weeks, but I have to echo Peniku8 for the most part. I finally finished and posted my "small" 21" design earlier today. It is still significantly bigger than the dimensions you have proposed. Have a look at how the front section was done. I don't think you can shrink it any smaller than that without major performance impacts. The simple slot that was posted above by Peniku8 is the other option for keeping it as small as possible but has some limitations also. The back chamber and ports I could shrink some more but only enough to get another few inches off of one dimension of the cabinet and that comes with compromises. The other option is to increase the tuning frequency. 30Hz + 21" driver starts to limit how far things can be shrunk. As a rule of thumb you will lose about 25 to 30% of your gross volume to bracing, cabinet walls, driver, wiring, etc... 60cm(wide)x68cm(high)x62cm(deep = 253L external volume for the subwoofer. I loaded your simulation data into HR and it says the system volume is 265L (Look under schematic diagram). Based on having 253L external volume available and factoring in the minimum 25% or so that you will lose to driver, bracing etc...results in about 190L best case for your subs net volume based on those outer dimensions. That's a long way off. My "small" CKRAM sub is 61 x 71.1 x 76.2 cm (330L) and results in a net volume of 257L. As far as air velocities go the lower the better of course. Port velocities almost always get high. This is almost always compromised. The horn or slot section can be kept much lower usually. Port compression starts kicking in a lot earlier than most people think. There's already some happening by 10ms. It gets progressively worse from there as does air noises. For the horn / slot section I try to stay below 15ms worst case with the amp I'll be using and <10ms is preferable. With the bass section ports this is almost impossible. I just try to keep it as low as I can, but it's always way more than ideal. I'd have to agree that you'll need to increase the cabinet size significantly or stick with a regular vented cab design. The cab size you've proposed will be tight even for a regular vented option tuned to 30Hz. I'm not trying to discourage you at all! Just trying to help you out.
  43. 1 point
    Thank you, I love every aspect of these. They sound incredibly good and since the driver is in a horizontal position, sitting on them is an experience lol! I can tune them 5Hz lower if I want to and that only takes about 30 seconds per cab to do. I revised the CAD files and overhauled some joints for the next batch. There are some visible seams which I didn't bother sanding and I will try to not use Kreg screws anymore.
  44. 1 point
    That skram is looking good @Tahoejmfc! I've been listening to my pair ... need to do some EQ'ing still and deciding whether to run the skrams with 2 ports plugged or wide open Here is John Wick 1's club seen peaks ... sealed subs are low passed at at 33 and skrams are high passed at 31 both at LR 48db/octs ... both skrams have all 4 ports open ... this is at -10 db reference with sub preout running 3.5 db hot vs all channels which are crossed at 80hz Anyone else crossing skrams with sealed for the ULF? LR or BW or any recommendations? Edit: I guess I should also add that these skrams are just stupid ridiculous and I'm pretty sure I could fit at least 1 or 2 more behind the screen ... Thank you Ricci!
  45. 1 point
    maxmercy-Please list your top 10 movies on Blu-ray for 2019 with the deepest and most powerful bass.
  46. 1 point
    Thanks for the good advices! I´ll be back with some testing results of the materials and maybe we try some cooling systems (not sure yet)
  47. 1 point
    DXF files uploaded to the first post...
  48. 1 point
    LOL Completely agree with you there Jay I haven't posted much, enjoying too many concerts and movies at home. Gotta give kudos to Josh for his exceptional masterpieces!!! <bows down>
  49. 1 point
    MK/SME, I remember doing some comparisons: I can revisit this if there is enough interest. Apparently we will get a 4k version in 2021. JSS
  50. 1 point
    So I played Godzilla King of the Monsters tonight.... The bass SCARED me with how hard it was hitting so I made an executive decision. I went from this To this Was still stupid loud with lots of impact, but not red lighting the Crowns as bad. Also by reducing the boost I was likely drastically reducing the distortion as these drivers aren’t really meant to dig this low...in addition to reducing driver stress.... I will do some REW later so I can see how much I lost below 20hz This is what the Original settings provided (the tan line) *Note* This was at a volume of 50 on the AVR. Not sure what SPL that equates to.... I was listening to Godzilla at 70.... so I’m sure it was significantly higher SPL....
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