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  1. This is the long delayed single driver sub similar in design to the Skhorn. Overall the performance goals and criteria were quite similar. Big surprise there! The Skhorn works so well at what it does that I didn't feel the need to reinvent the sub for this one. This is primarily designed as a professional sound reinforcement or live sound style subwoofer. Big output and clean sound in very big spaces, while covering the typical bass heavy range of music, has always been the primary mission for this sub. Same as it was with the Othorn and Skhorn. It can and I'm sure WILL be employed for other types of situations, but it's a festival or club sub that just happens to be flexible and neutral enough to work in a variety of scenarios. The main differences between the Skram and the Skhorn are as follows. Optimize it more for the cost effective 21's like the 21DS115 and Lavoce SAN214.50 rather than the Ipal drivers like the Skhorn. The Ipal's still work of course, but I relaxed things a bit for the drivers that are a little easier to afford and power. Increased size: Originally I wanted to basically saw the Skhorn in half and slap a top panel on there with modded bracing. It would be a very compact 21" sub, which is great, but the driver would fire directly into an outer panel and even with bracing this is a lot of energy being beamed on axis into a large outside panel. I've never been a fan of high pressure loadings with big drivers that do this. I always want the direct on axis energy from the cone to act on internal panels that are going to keep this energy inside of the cabinet better. This required a rearrangement of the internals. I also added a bit of size while I was at it. I decided to stop at a size that was significantly smaller than the full Skhorn, but not as small as a true half. If this cab is too big or heavy you could always build the true half Skhorn, which would be 24x32x27.71. Increased vent area and slightly increased vented chamber volume. This should help the noise, compression and output near the vent tuning. Increased vent area and length means that the vent pipe resonance is lower in frequency than the Skhorn. I'm, expecting that the response will be less smooth above 150Hz, but that's the tradeoff made for bigger vents. The Skram has 4 vents instead of 3 like on the Skhorn. I decided to add one more for even more tuning options. Tuning with all vents open is basically the same. Being a single driver design, the Skram does not have the dual opposed drivers for mass induced vibration control like in the Skhorn. Other than these changes I would expect that this design behaves and sounds very similar to the Skhorn. I'd expect that the two could be used together without issue. They are more alike than dissimilar. Skram Dimensions: 24"x32"x36" (609.6mm x 812.8mm x 914.4mm) Weight: Cab=115lbs or 52kg projected (Driver will add another 25 to 55lbs (11 to 25kg) depending on the driver. Vent Tuning: All vents open = 29.5Hz / 3 vents open = 25.5Hz / 2 vents open = 20.5Hz / 1 vent open = 14.5Hz Each vent is greater in area than a 6" pipe. All vents open is equivalent in area to 4x 6" ports. All of the usual pro 21's should be a good match. 18Sound 21ID, 21NLW9601 B&C 21DS115, 21SW152, 21Ipal RCF LF21N551 looks decent Lavoce SAN214.50 Eminence NSW6021-6. NOTE about the prints! These are extremely detailed due to being designed in Solidworks and the plans from which my personal cabs would be built. The simplified layout drawing is really all that should be adhered to to build this sub. The bracing and hatch can be simplified to suite your own ideas or the tools available to build the cabs. Just make sure it is solid! Any or all of the hardware can be deleted or substituted or modified to suite your needs. Even outer dimensions can be adjusted within reason. Think of the plans as a chassis guideline that can be modified to taste. You don't have to put all of those holes in your braces or use the handles, a half inch roundover on the cab edges, add a cutout for a plate amp on the hatch, etc... Skram print.pdf skramcutlist12mm.pdf Skramcutlist18mm.pdf DXF files... Back Brace 1^Skram_TI x2.DXF Back Brace 2 ^Skram_TI x 2.DXF Bottom Braces^Skram_TI.DXF Bottom Brace^Skram_TI x 2.DXF Front Brace^Skram_TI x 2.DXF Mid Brace x 4^Skram_TI.DXF Top Brace^Skram_TI.DXF A^Skram_TI.DXF Back^Skram_TI.DXF Bottom^Skram_TI.DXF B^Skram_TI.DXF C^Skram_TI.DXF D^Skram_TI.DXF E^Skram_TI.DXF Front^Skram_TI.DXF Hatch Brace Small^SKHorn.DXF Hatch Brace^SKHorn.DXF Hatch^SKHorn.DXF MirrorSide^Skram_TI.DXF Double - Middle Two.SLDPRT Double - Middle Two.SLDPRT.DXF dxf_filelist.txt Single - Left or Right.DXF Triple.DXF Back^Skram_TI.DXF Bottom^Skram_TI.DXF E^Skram_TI.DXF Side^Skram_TI.DXF Top^Skram_TI.DXF Side_1^Skram_TI.DXF Top^Skram_TI.DXF
    9 points
  2. Final quarter of 2017 update. JTR Speakers Captivator 212Pro results have just been posted. KRK Systems 12S2 subwoofer testing is done. Should be posted next. WW Speakers / Mark Seaton designed X21 cabinet loaded with B&C 21DS115-4 driver testing is done. Will be posted ASAP as well. This was tested with both vents open and with a vent plugged and with both the Powersoft K20 and an Inuke 3000DSP. That's 4 full measurement sets. We're killing a lot birds with one stone on this one. We have some information on the Inuke 3000DSP amp driving a real load. We have the 21DS115-4 driver itself, which a lot of people are interested in and lastly we have the X21 vented cabinet which is available off the shelf to fit a variety of pro 21's. I tell you the cab is built solid and of course Mark designed it well. It is not cheap but it certainly offers an easy button option. Next up is a set of 3 subwoofers from one of the commercial vendors. I'm not totally sure these will be public on the site since the MFG reserves the right to decide whether the results are public or private. I believe they will be though as so far their behavior appears to be well designed. And...After that...I have a couple of cabs from a pro audio company that will be on deck. Not sure these will be public yet either but I suspect so. I'm trying to get this all tested and posted by the end of the year. That's the goal. I have more DIY type driver tests sitting in the wings too.
    9 points
  3. So close. Loading drivers and doing the wiring today
    8 points
  4. 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
    7 points
  5. Update to powering the RF 19's. The 8 sealed in the HT will now be getting a pair of SP2-12000's. Each 6k module power 2 1ohm T3S1-19 drivers in series in a dual opposed sealed cab. This switch is mostly because the SP amps have less fan noise than the K20's. Also they have slightly better extension below 10Hz. The K20's are going to the band spot to power the MAUL's. Fan noise doesn't matter there. Each MAUL has 4 T3S1-19's wired in series for a 4ohm nominal load and will see a whole bridged K20. Yay headroom... Got power?
    7 points
  6. 6 points
  7. Blowing out the cobwebs today
    6 points
  8. Been almost 3 years in the making. Huge undertaking. Just finishing up the last few features but we're closing in!
    6 points
  9. I've got a couple of pro woofers on hand for 2018 so far. I need to do some more testing with the 21DS115-4, but I also have a JBL 2269H 18 and 2 18Sound 21's the 21NLW9601 and 21ID. I also have a couple of vented pro subs I didn't get to in 2017. Even more JTR Speakers testing is on the schedule for when spring gets here.
    6 points
  10. Kong: Skull Island (Dolby ATMOS) Level - 4 Stars (111.38dB composite) Extension - 5 Stars (1Hz) Dynamics - 5 Stars (28.84dB) Execution - TBD Overall - TBD Notes - This film delivers bass in spades, especially in the shake-and-move-stuff wheelhouse range of 12-25Hz. Clipping analysis shows flat tops in nearly every channel, Center is most egregious, but all the clipping appears to have rounded edges as if some sort of limiting was put in place like Pixels, so not completely objectionable, like Tron:Legacy clipping was. LFE channel clips with sharp corners, but low-pass filtering will smooth them out. Better movie than anticipated, but it almost always seems that way when you expect nothing from a film. Good surround use, good soundtrack. BEQ should make this a structure-endangerer. JSS
    6 points
  11. I just attached the plans to the first post for anyone that wants them. I've had 3 or 4 other people request these plans over in Europe. Hopefully there will be some more documented builds coming up.
    6 points
  12. Othorn files. OTHORN print AUTOCAD 2000.DXF OTHORN DXF scale print.pdf OTHORN print.pdf
    6 points
  13. Hi everyone! I'm new to this forum, after beeng very active on different forums here in Norway. Over the years I've built and restored about 200 different cabinets for speakers in my small workshop, and my latest one is the Skhorn. I've also built six Othorns, but these Skhorns are among the largest cabinets I have done. I built three, two for a customer and one for myself. All the parts are cnc'd out of 18 and12mm BB at a friends workshop. I think the build was relative easy compared to the Othorn. I'm going to use the Ipal driver, and will start testing tomorrow with a Crown Itech 6000 amp. I'm looking forward to that!
    5 points
  14. I don't see myself doing many TH or FLH's in the future. FLH makes more sense for systems without size restrictions, looking to extract maximum from a single driver and those without the need to go very deep. I might employ it for 80-300Hz range or so in the future but it's doubtful I'd do a subwoofer. 30Hz extension is bare minimum for something I consider a "sub". FLH's can be bested in the lower register by smaller more output dense alignments. They can sound very good. TH's I've found that the limited bandwidth and limitations imposed by path length needs and folding options cause them to be difficult to design well. More importantly the harmonic resonances in the response are audible and can cause major issues with harmonic distortion and ringing. In order to keep this up out of the sub bandwidth, well damped and above the low pass filter it's difficult to get extension much lower than the Othorn IMHO. TH's are best with extension to the 30-40Hz range IMHO. When done right they can sound killer as well, but the driver is more exposed usually so they have a bit more operational noise than FLH's. Better driver cooling though. The hybrid BP's I've been doing can be smaller than TH's, much smaller than FLH's and can almost match the TH's output. They are still somewhat tricky to design well and package but easier than a TH and easier to build. The response can be made to lack the upper end response issues more easily. The driver is buried in the cab so mechanical and operational noises are diminished, which is a big deal to me, but the air exchange and cooling is a lot better than a FLH. They are a bit more tolerant of a wider range of drivers as well. The sound is definitely clean and visceral when done right. In summary I have heard excellent examples of all 3 sub types. I'm a big fan of burying the drivers in the cabinet. Reducing the direct operational noise of the drivers especially when operating at high excursion / high output scenarios makes a large difference to me. The tradeoff is it may be difficult to tell just how hard the driver is being worked.
    5 points
  15. Bolserst is a long time contributing member over at DIYAudio forums. He has developed this spreadsheet that will take an impedance measurement and calculate the complex inductance of a driver. David McBean the author of HornResponse has added the capability to simulate using this data into HR. This is a much more accurate way to simulate and design speakers and subs. In short if you are designing bass systems using modern, high power, long throw drivers and you are not accounting for complex inductance in your modeling; The models are probably not representative of what you would be building. Previously you would need to purchase costly software in order to derive and simulate using these parameters, or figure out a way to roll your own way. The spreadsheet imports a text file of an impedance measurement and calculates the complex inductance specs. Additionally if you have an added mass or Vas (Known air volume) impedance measurement you can also import it and the spreadsheet will calculate all driver parameters needed for modeling. A driver file can then be exported for use in HR. Semi-Le_Calc_V3.xlsm
    5 points
  16. I've seen it, even posted in the thread. There are many ways to fold this style of cab up. There are a couple of other ones floating around also. Other than that I try not to comment on other people's designs too much. Many times they aren't ever built, or if they are there is never any reliable objective results shown. Who knows. In other news I have picked back up on working on a single driver version finally. I've basically got the cab layout and fold nailed down. I just need to decide on bracing and hatch then put the models and print together which takes a bit. Hopefully I'll have it done by the end of the month.
    5 points
  17. 5 points
  18. Agreed...There have always been a lot of hang ups with terminology in audio circles and fixation on defining things by a strict set of rules. In order to be an IB the back volume must equal at least 10X VAS...Waveguide vs horn etc... I consider the Skhorn a hybrid 6th order design. Fun fact...Skhorn is pronounced like the word scorn and I gave it that name because after exploring all the options I could think of attempting to do a horn of some type, I ended up not doing a horn at all. No matter how much I wanted to, and I really wanted to make a horn at first, I simply could not make a horn this size that would perform like this cab. After giving up and scrapping all the horn ideas for a hybrid 6th order BP I called it Skhorn as a middle finger to bass horns in general. Most people think it's called that because it's some kind of horn LOL.
    5 points
  19. I vote that we let users add graphs, content, build plans, etc. 1 guy can only produce so much content. As far as social media I'll let you guys in on a secret. I've never been active on any form of social media. I don't plan to be either. From what I recall Kyle isn't either. That's why we don't have any of that for DB! Neither one of us wants to deal with it!
    5 points
  20. I've mentioned it a few times before. A pair of JBL 4675C's. The 2226H drivers out of the double 15" (4508A) bottoms I sold off and replaced with AE TD15M-4 drivers with the Apollo upgrade. They are wired in series. The big 2360A "butt" lenses still have the 2446H CD's on them. Those sit on top of the MAUL's. It is a tri-amplified stereo system run from a Peavey mixer into a DCX2496 which provides processing and routing to the amps. The current amps are a 20 year old Mackie M1400i on the 2446H drivers (Run from about 600Hz up.), a Crest 8002 powers the TD15M's which run about 80-600Hz roughly and a single SP2-12000 currently has a MAUL on each channel running <80Hz. There's no surround sound and I never replaced the old projector after it died a few years back so there is no video right now either. It's just a mammoth stereo or PA as needed. It's nothing special but does the job. Eventually I planned to swap out the 2446H's for some BMS coax's or something Be and probably change the lenses too. Now I'm having thoughts of doing something different for the mids and highs entirely. Try to roll my own Synergy's or other design? Not sure what yet. I'll probably upgrade the amps first. Eventually I'll put my K20's one on each Maul and move to SP's at the house so I won't have to deal with fan noise at home anymore. I want to get a newer amp for the CD's. Only class AB or H for those though. I still don't think class D is quite as good for HF. I might just go with an A500. The power requirements on the CD's is almost nothing even at ear splitting levels. The room is in an old rundown, warehouse / factory, in a ghetto part of town. Myself and the other musicians I work with, have been renting there for 8 years or maybe more. The whole building just about is rented out to musicians, artists or people needing storage. The outdoor test spot is right out the backdoor. The room itself is a shotgun shaped space about 18ft x 15ft x 36ft. Roughly 10,000cu ft. I'm guesstimating and could be off some, since I've never actually measured it. Walls are double carpet hung over sheetmetal and studs with main building supports in there too. Flimsy and leaky as hell but the carpet hanging from the walls and the directivity of the horns actually keeps the space relatively dead. Every surface in the room except for the garage style door and the ceiling are covered in carpet. The room is over the basement level, but the floors are 4 to 5 inch thick cement type material over timbers, so it will shake some, but not easily like a suspended floor in a house. It takes a bit more energy. Ceiling is the same deal. Back wall is a brick interior wall with carpet over it. The back ground noise level is high usually of course. There are no placement options really as the room is jam packed with equipment of all sorts. It is not ideal and there are all sorts of acoustic and structural issues that color the sound. For one my drums usually sit directly in front of one side of the stack. Thankfully the horns are 8 or 9 ft off the floor well over top of them and the bass just goes around, so most of the sound ends up in the right place regardless. None of that matters really because that's not what it's about in there anyway.
    5 points
  21. Sorry, not very descriptive in my post lol. We had 5 Skram's out under my Danley Sh-46 for 3 days this weekend, sadly I have a driver stuck in customs so the 6th Skram stayed at home. First time feeling like I had abundant power and amplification to really see what everything could do, used 3x CVR 3002 on subs, 1 skram per channel and 2x Crest Prolite 7.5 bi-amping the Danley's. Really happy how everything's come together, ran flawless all weekend and sounded fantastic with tons of headroom.
    4 points
  22. No offense to RF as they do have some sharp guys but the whole, driver optimized for sealed / vented / BP and don't use it in another alignment, is for the most part antiquated thinking from back before modern signal processing. There are drivers that are better suited to some jobs than others make no mistake, but this is not one of those. Usually the reason you will hear that drivers are not suited for sealed is the qts is too low (IOW too efficient) and without EQ it will be bass shy because the top end gains sensitivity quickly and overpowers the low end without EQ. In this case RF is assuming that these drivers are going to be used for car audio SPL comps and the like and ported will be way louder than sealed and will also handle high power inputs longer. I can see why they would recommend this for their statement competition driver but if the app is not putting up big scores in a Tahoe it's one of the top high power sealed drivers available. It's 2020 and unequalized frequency response is much less of a priority than it was 30 years ago.
    4 points
  23. 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.
    4 points
  24. 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!
    4 points
  25. Wow! What complete and utter rubbish. I'm not going to question the author's reputation as a mixer, which may or may not be well deserved, but most of what's written there is embarrassingly wrong. It's hardly unique to the author. He's just perpetuating myths that are widespread throughout that community. These myths come about because people are trying to relate their subjective experiences with sound to objective principles, without sufficiently understanding the latter. One of the worst issues I see are that he blames "muddy sound" on rooms being too small for the wavelengths. That's only true in a very ironic and roundabout way. It ignores the fact that mud is at least as serious of a problem for frequencies in the 100-500 Hz range, whose wavelengths are also long enough such that the speaker/monitor interacts with nearby large boundaries from walls and in particular the mixing consoles (!!) in widespread use. The picture even illustrates what appear to be a bunch of narrow EQ cuts, which while much less offensive than equivalent boosts, nevertheless are likely degrade the sound quality of the tracks substantially to the extent that they reflect problems in the monitoring system vs. the actual soundtrack. Worst of all is where he suggests using a sub-harmonic synthesis plug-in to "boost [the sub frequencies]" *as an alternative* to installing a subwoofer into the monitoring system. This is completely confusing the critical distinction between *adding more bass to the monitor system* and *adding more bass to the soundtrack*, which I would expect any competent mixer to understand and appreciate. Yet, this confusion also is not unique to this author and seems to be widespread among mixers. And because the mixers running these plugins can't hear what they are actually doing, this is actually a "worst of both worlds" solution. To emphasize the wrongness there's this sentence at the end: And what exactly do plug-ins, used to alter the soundtrack, have to do with whether *your monitoring system* has a subwoofer? Nuff said. Now with that criticism out of the way I want to point out that I don't think the author is incompetent nor is he trying to deceive people intentionally. He is correct that the mid-range is the most important part of the spectrum, even for "bass" instruments and "bass" music genres. He is writing based on real lived experience of how systems with subwoofers sound and what it's like to work with them. The reality is that good sub integration, with or without "auto EQ" tools, is quite difficult and is beyond the skill of many mixers such as himself. For many such people, monitoring with *no* subs may be better than monitoring with *bad* subs. It's hard enough to deal with the issues in the 100-500 Hz range that are common to every studio using "near-field" monitors and/or a large mixing console. Throwing a sub into the mix is likely to only make things worse. I also agree with his implication that soundtracks often have too much sub boost in them. This is very common for movies which (surprise surprise) are mixed under bass deficient conditions, but it's also becoming quite common with music releases. I get the feeling that excessive sub boost on soundtracks may be the major reason for him to write the article, yet his advice is essentially the opposite of what's likely to help. At the same time, I feel sorry for him and many others like him because it's clear to me that he has probably never heard a good small-room bass system in his life, despite his professional pedigree. They just assume that bass cannot be reproduced in small rooms like it is in large rooms or outdoors because they haven't heard it done before. Perhaps if they knew what was actually possible, they would have a quite different opinion.
    4 points
  26. It’s not how I will normally deploy them... but figured they should hang and and get to know each other https://imgur.com/gallery/r5UkOor
    4 points
  27. The output power of a K20 vs an X4 K20: 145 V RMS for less than a second at 2.05 ohms both channels driven Then it limits to 58 V then it goes down to 52. This means 10.5 kw per channel for long bursts 1680 watts for 4-10 seconds 1350 watts per channel for almost a minute then thermal protection. Similar output is offered at 2.5 ohms , 70 V RMS for 4-10 seconds. This time constant depends on the internal temperature. The X4 can do 2950 W for 2 seconds at 4 ohms, then 1600 watts per channel at 4 ohms for 20 seconds single channel. 2*2650 w for 0.8 seconds then 950 watts per channel at 4 ohms for 12 seconds 2 channels driven After 20 respectively 12 seconds, the amp shuts down the output, going into protection. There is also a review of the X4 on Production Partner showing interesting result with all channels driven at the same time with the same signal. Ipal module is pretty small. Maximum output power is 4500 watt for 0.3 seconds then it will reduce to 2500 watts for 3 seconds then it limits to 700 watts continuous for 35 seconds then down to 400 watts for long term. K3 at 2.3 ohm load will deliver 3150W per channel for less than 0.4 seconds both channels driven, will then go down to 1450 for a second then slowly down to 500 watts a channel in 1.5 seconds. Why I receive this thread? Because now Powersoft launched a new model, X4L , a forced bridged X8 amp, that has 4 channels with 300 Vpeak and 140Apeak. If 2 X4 channels can deliver that sustained power and program power, then I believe the new X4L will surpass the K20 if asymmetrical loading is used. The idea is that a series loaded 2*21Ipal loaded Skhorn presents a pretty high minimum impedance for a K20 so mostly the output is voltage limited in normal use. Bridging the amp would be too much for the long safe run and very expensive. With this new model, voltage will not be a problem anymore, the maximum average output power is high enough for using 8 21 Ipal on 4 channels and. It can be almost 3 dB louder on peak output than with the K20 but with awesome processing and three phase ready.
    4 points
  28. For anyone who might find it helpful. Attached are cut lists to build 2 skram cabinets. I tried many combinations of 4x8 and 5x5 to find the route with the least leftover waste. Factoring in cost of materials for me in Canada, $73 per 18mm 5x5, and $105 per 18mm 4x8, this was the cheapest route... your mileage may vary depending on material costs. Will require 6x 5x5 of 18mm and 1x 5x5 of 12mm costing about $487 Canadian. I used the Cutlist optimizer app. All pieces are accounted for as rectangles, some finish cuts will be required after the fact Skramcutlist18mm.pdf skramcutlist12mm.pdf
    4 points
  29. It's been ages, but I've finally gotten a fix for the "stacking" problem in the latest MSO version. An article (PDF) that I recently found detailed how to impose global constraints in the Differential Evolution algorithm without causing convergence problems. I implemented it and it seems to be working well so far.
    4 points
  30. Some progress shots. We have decided to do a shoot out between the B&C 21SW152, RCF LF21N551 and 18 Sound 21NLW9601. I will share the measurements and results in a couple of weeks.
    4 points
  31. Finally some pics of the assembly process. The MW's of @lilmike are finished on Wednesday.
    4 points
  32. Going back to my issue with the drivers in electrical series, I can say there is absolutely no difference between them linked like that or parallel. All my tests and measurements showed me nothing changes, a small voltage difference is present, but only 1-2 V at 60 V sines.
    4 points
  33. fwiw this release can show the bass managed result of a set of filtered channels in the app, updates live as you change filters and reports on headroom available - https://github.com/3ll3d00d/beqdesigner/releases/tag/0.5.0 I recommend using a decimated track if you want this to perform acceptably so that means it isn't a perfect simulation, close enough though for this purpose IMO
    4 points
  34. 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.
    4 points
  35. The idea behind this build is to learn. I started my company to sell subs, because here in this part of Europe, there is a very deep lack of powerful high quality bass Mostly I wanted to see people's reactions, the power density, the extension, to see if the weight and dimensions are a big problem. They are now installed in a basement where we got them by hand. I wanted to see about the power compression, port noises, chuffing, I have learned how and why to install protection grilles, handles, wheels, I wanted to see if I can improve their performance in any way without any other compromise except cost and complexity. I wanted to learn about braces, hatches, accessibility. These gave me a good insight on all of these These subs will be loaded with 21ID and Ipal modules and will permanently stay in rent in a small club where people love good sound. Based on what I learned, I'll continue my other designs and after all 4 designs will be ready and I'll have a stock of 4 of each, I'll publish the specs, measurements, graphs , technical details , pictures and videos and I'll start selling those.
    4 points
  36. 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 .
    4 points
  37. Here is a RTA of thunder I took with my calibrated-to-4hz Dayton EMM-6 and a TASCAM US-1641 which starts dropping off at 20hz. The mic was inside a window behind the curtain with its windscreen on and SPL is uncalibrated but it clipped my mic just when it hit that peak at 4hz, and I had my mic at 3/4 of gain, so it was a pretty loud peak. The second image is with no smoothing was taken during the RTA. The first has 1/48th octave smoothing and is the total peak. I live far out in the country so there are no sources of infrasound from vehicles or factories except for a very low level 14hz tone from a glass plant about three miles away.
    4 points
  38. Make sure you put a finish on the cab before you install the driver. I have had cabs that went without finish for 3 years, b/c after the driver goes in, it is so easy to just listen to it. JSS
    4 points
  39. The Incredible Hulk is still the track I compare all others to. A close second is the Star Trek reboot, War of the Worlds, and all of the 5-Star films on the first page of the thread. For lots of 20Hz and below energy, Battle:LA is hard to beat as well. JSS
    4 points
  40. 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?
    4 points
  41. Gjallarhorn 2 plans. GH 2 print.pdf GH 2 print.DXF
    4 points
  42. I don't know if you saw my skram built on page 26 or so, I built 2 of them, made of popplar plywood with a carbon-epoxy layer around to make it stiffer. Then we made the front out of 25mm transparent acryl glass, just to loose the weight savings due to the 10kg (just a wild gues, I forgott the real numbers) of those fronts haha. We didn't put them on a weighting scale yet, but without the heavy front, they would be ridiculously light! So light that we will make a base filled with sand to make sure they dont move more than the drivers do. We also didn't fire them up, but that will happen soon, hopefully... so I cannot say anything about the stiffness and if there is anything hearable compared to our baltic birch skram, but I will male a post as soon as that happened. We will make 2 more of them, without acryl glass front, because we have the materials, but I also have to say that it is a hack of work to prepare all the plates, and also, it is really expensive of course, so i dont think that we will do this again after those next two.
    3 points
  43. Hey guys. While not as rigorous as the excellent testing in this thread I put together a little vid doing some light testing and listening comparisons between the chinese CVR branded 3002 amplifier up against a Powersoft K-10. Might be a good option for people looking for some decent performance at a good price point. Maybe you will find it interesting. Ill have this set up for a couple more days so if you're quick and send me a request for ideas for further testing I can try to accommodate
    3 points
  44. Apologies for taking so long to give a review. I *finally* watched this tonight! I just kept putting it off because I've been working so hard on new/improved treble optimization. I'm still not done and was thinking I'd save it for when I'm "done", but my wife got tired me of putting it off. I'm glad I listened to her. I think this is my new favorite soundtrack, and the BEQ takes it to 110%. I watched it (BD/Atmos soundtrack) at around "-5" on the MV. (I forgot to check to see if there was any dialnorm modification to that, so it might have been less). My system is configured with a pretty generous house curve (up to 10-12 dB "hot"). Pretty much all of the bass sounded full bandwidth, and the frequency balance was excellent. At no point did the low stuff overwhelm the mid-bass nor any of the rest of the spectrum. The sound effects were very cohesive from top to bottom, and the tactile sensations were detailed, articulate and at times brutal. There were multiple jaw-drop "jump out of my seat" moments where things just went BOOM spectacularly. The surround work in this mix was a big part of experience as well. What can I say? This this a superb demo piece: for my bass capability, my overall sound capability, for BEQ as a technique, for superb sound design, etc. It is state-of-the-art. A big thanks to @maxmercy for taking the time to do this!
    3 points
  45. I think what db does better than many other sites / forums is that discussion here can be backed by real numbers. Subjectivity, while is fun to discuss and does have value, can't really run unchecked to the existing data. Now, data does not capture everything, and I will admit that there is a certain adoration I hold for some subwoofers that don't even hold a candle to most things in our list and I'm not shy about it. Its fun to discuss everything, big, small, expensive and cheap, don't worry about getting ridiculed.
    3 points
  46. Thanks Kyle! Actually, he jumped the gun a bit here and declared victory while the update was still running. NOW it's all done. Edit: Total count of posts updated: 169!
    3 points
  47. Right...That's what I mean. If you preserve incredibly high dynamic range with digital media that means your average level is going to be very low volume/signal strength, requiring much more gain to get the average sounds to a typical playback level. I wish there were more recordings like that. Just turn up the volume and the problem is solved. But the problem is, if you attempt to play a regular heavily compressed song after, it will blow your head off and make the dynamic recording sound weak in comparison. That's exactly how the loudness war started. Get the average level as high as possible. Louder=better or more noticeable. I'd like to see groups make 2 mixes. The squashed "radio" track and a much lower average volume mix with more dynamics. I see this issue as separate from your speaker system being capable of producing huge short term output. I consider that a reasonable goal that improves sound quality on a number of fronts.
    3 points
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