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  1. 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.
  2. 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
  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
    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!
  5. 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.
  6. 3 points
    Hope everything is good with you Luke. Good luck with the sale.
  7. 2 points
    SME answered well. It's complicated. With almost any driver the performance starts to degrade as it is pushed to higher excursion. This really cannot be answered with a single number like xmax that mfg's try to use. The 21Ipal will go to about 30mm one way if not a bit more if you REALLY hammer on it but it does not sound good by then. It gets cleaner at 20mm one way, and again much cleaner at 10mm one way than 20mm.
  8. 2 points
    Yes---for some definition of "significantly". If you look in B&C's docs, they may describe their methodology for XVAR. Someone else's definition of "Xmax" may yield a different number. The measurements on DataBass don't give a specific number but simply show how compression and distortion increase as the driver is pushed toward its mechanical limits. Realize also that actual distortion depends on more than just excursion. Certain aspects of the cabinet design can suppress or amplify the effects of distortion in the motor.
  9. 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.
  10. 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
  11. 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
  12. 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.
  13. 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.
  14. 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!
  15. 2 points
    Finally! Measurements coming soon. If the weather is on my side.
  16. 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.
  17. 2 points
  18. 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).
  19. 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!
  20. 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.
  21. 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 😫
  22. 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
  23. 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
  24. 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
  25. 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.
  26. 1 point
    So I've been lusting after a Parts express UM18-22 18" with sealed flat pack. They were out of stock when I looked but I found a CraigsList add for two ultimax's in a crazy looking Dipole box. Very close to this build here https://www.linkwitzlab.com/woofer.htm I've been telling people that the bass is directional and no one wants to believe me. So I finally measure both on-axis and 45 degrees off-axis The build is incredibly inefficiant as I'm currently bridging a crown K1 at 1100wats 8ohm and have to boost sub output from the Denon receiver quite a bit. Not so much nearfield but anywhere else I put in the house. I have a sealed flat packs on the way so I can separate these beasts and pressurize the room better but the fact that I can rattle my brain while watching a movie and have my wife, literally next to me on the couch and she doesn't have to endure the bass that I love is kind of magical. Not sure I want to take this thing apart now. Just thought I would share.
  27. 1 point
    In the end though, you have to build & test to be 100% sure. There are (also empirical, not theoretical) studies / papers on the topic, from the AES for example, that are freely available; the issue has been figured out for decades. The conclusion overall is that you should always use the maximum port size that you can possibly accomodate in a speaker box, because there will always be some compression. There are other concerns like port resonances (only relevant for full range boxes, not subwoofers), or cooling (only relevant for PA subs).. but generally, the larger the port, the better. Flared ports reduce air turbulence at the port ends, which results in noise. So flared ports reduce noise. They do however hardly or not at all reduce compression, which is a result of an inadequate inner port cross-section area. Port noise and compression are / can be two different things.
  28. 1 point
    Good guessing can save a lot of time and money that would be spent building physical things that don't work.
  29. 1 point
    Hello also from Denver here! You started in on one of the Othorns already? I'm not sure how far along you are, but you may want to consider the Skhorn or Skram instead. They have much cleaner response to well above 100 Hz, and I think most people here regard those two designs to largely obsolete the Othorn. If you have a choice, I very strongly suggest you go with one of these newer BP6 designs. If you already have Othorns you want to use, then I'd say the situation is a bit of a mixed bag. The 80-100 Hz region is pretty narrow---essentially 4 semitones (or a major 3rd) apart. However, crossovers are not an all-or-nothing thing but involve blending over a pretty wide range, even with e.g. 4th order slopes. IMO, the Othorns will probably sound even better crossed even lower at like 60 Hz, at which point, a dedicated mid-bass section (for say 60-150 Hz) starts to make more sense. Looking at Ricci's compression sweeps for the Othorn, I don't expect EQ applied above 100 Hz will be very help helpful because the response above 100 Hz actually changes a lot with the signal level at medium-to-high levels. EQ which sounds good at low signal levels might actually make things worse at high signal levels.
  30. 1 point
    This is from the MK1 HS-24 so I'm sure the MKIII has had some tweaks made. In the absence of the complex inductance data for the MKIII I'd suggest using these specs. It'll be closer than not modeling semi-inductance as it's pronounced in these Plug these into HR by double clicking on the LE box. It is activated once the label turns green. Measured Complex Inductance Parameters Re' 3.572 Ω Leb 0.951 mH Le 14.868 mH Rss 74.784 Ω Ke 0.451 sH
  31. 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.
  32. 1 point
    Interesting. I wonder how fine-grained the IPAL system is here? Does it adjust EQ in real-time or just gain? If it adjusts EQ, how tight is it? Do the sound characteristics noticeably wander through a live performance? It's not too hard to monitor DC resistance and adjust gain in real-time, but that may not be good enough. I expect that thermal changes manifest over seconds to minutes or hours. If we assume all of the thermal effect is to raise the coil DC resistance, then the nature of the non-linearity is such that we can understand things in terms of linear response that changes with time. This is not possible for inductance because inductance can fluctuate much more rapidly, with each stroke of the driver. Using a linear analysis, we consider a sine wave at one single frequency at a time. The impedance (Z) describes the relationship between voltage (V) and current (I), and we can describe the behavior completely if we let V, I, and Z be complex quantities with *real* and *imaginary* parts. Each quantity can alternatively be described as having a *magnitude* and *phase angle* part. Both descriptions are useful depending on the circumstances, and one can convert between them using arithmetic formulas or geometry. A complex quantity can be represented as a point on a 2D X/Y with x = *real* and y = *imaginary* parts. Draw a line between this point and (X=0,Y=0). The magnitude is the length of this line and the phase angle is the counter-clockwise rotation from the positive part of X-axis to the line. (This article on the Complex Plane might be helpful.) For V and I, the magnitude is the absolute value of the peak amplitudes of their oscillations. The phase angle describes the *phase shift* which essentially describes the temporal shift while recognizing that a continuous sine wave is *periodic*. Periodic means it precisely repeats at the same interval. If you shift a sine wave by exactly 1, 2, 3, etc. periods, the result is exactly the same. So, it makes sense to represent the amount of time shift as a *phase rotation* on a circle. Analogously to Ohm's law, the relationship at a single frequency is: V = I * Z or (rearranged) I = V / Z or (...) Z = V / I. The rules for multiplication/division of two complex quantities are as follows: (1) multiply/divide the magnitudes to get the new magnitude. (2) add/subtract the phase angles to get the new phase. Therefore the meaning the impedance phase angle is the phase difference or change between V and I. Note that this math is generally useful for analyzing oscillating signals including audio acoustic transfer functions (i.e. frequency response magnitude/phase). So if we can easily multiply and divide complex quantities using the magnitude/phase description, what is the purpose of the real/imaginary description? The latter is for adding subtracting such as when analyzing a series electrical circuit or acoustic interference effects. The rule for adding and subtracting complex quantities is to add and subtract the real and imaginary parts independently. For impedance, the *real* part is called the *resistive* part, and the *imaginary* part is called the *reactive* part. As expected, a pure resistance (i.e. straight a wire) contributes only to the real/resistive part of impedance, and the tendency for oscillating energy storage/release manifests only in the reactive part. Ideal (as in zero resistance) capacitors and inductors only contribute to the reactive part. Do note that the resistive part of the impedance is not always equal to the DC coil resistance. The acoustic properties of the subwoofer contribute to impedance (both resistive and relative) as well. As such, we can conclude that increasing the DC resistance by heating the coil will alter the frequency response by different amounts depending on both the magnitude and phase of Z. The increase in Re adds directly to the resistive part of Z. The peak current is reduced, but the amount of reduction depends on how much the *magnitude* of Z changes. So you can plot the initial value of Z on the Complex Plane and then plot the *new* Z shifted to the right by the increase in Re. Then, the current will decrease in inverse proportion to the change in distance between each point and (x=0,y=0).
  33. 1 point
    18Sound have some interesting drivers that have little/no inductive impedance rise using a technology they call AIC: http://www.eighteensound.com/media/W1siZiIsIjIwMTgvMDkvMTAvMTFfNDZfMDNfNzU1X0FJQy5wZGYiXV0/AIC.pdf http://www.eighteensound.com/en/products/lf-driver/10-0/8/10NMBA520 I think KV2 might be using their drivers.
  34. 1 point
  35. 1 point
    @Ricci Instead of the "8 point star" design as the throat braces, would a "tic-tac-toe" pattern work as well? Something very rough like this?
  36. 1 point
    A few of us have sh50s and skrams. One even has sh50s, skrams, and skhorn 😲. There's also an individual that had sh50s for LR with a sh96 as a C who now has one skhorn. I think the quote you shared explains things quite well. All I could do is reiterate that with a different subjective contribution. The synergy horn design is marketed as a true point source. They do magical things for my ears in my room. Combined with some skrams and the only thing I may end up changing is adding more skrams. I have 2 extra channels on this Amp that aren't beigg used right now, so that's just a waste, right? If you have an opportunity to listen to any synergy horn, I highly recommend it. Danley allowed the unity horn to be implemented by Yorkville. There was a u15 and a u215 IIRC (passive and active versions). Those designs were not full point source as the bass was handled by drivers outside of the unity horn. However, they can still be found and are usually not too expensive. Could be another option to pursue in hearing a danley loudspeaker design.
  37. 1 point
    Soon we will know..!
  38. 1 point
    Exactly. Btw, you don't have to fill out all 4 sections. You can input S45 data into S34 and leave S45 off (all values 0). What angle does your horn have? With your values it almost looks like the offset part is angled at some 20°, is that what you're trying to do? From the parameters it looks like you're doing something like firing into the back at quite an angle with a straight section running along a side wall/bottom to the front. Quite ambitious packing that much of a front chamber and a 96cm long port into a space this small. Are you sure the back chamber volume is correct? Looks like a bit too much for a cab of the dimensions mentioned earlier. I also noticed that the quarter space sim (plus baffle gain and -12db) matches my real measurement much better. I multiplied the Hornresp output with the calculated half space baffle gain in Edge and basically got the same voltage sensitivity (-12db) curve as I measured, which was really satisfying. The driver did get a healthy 4 hour break-in period and I've used Ricci's semi-inductance parameters.
  39. 1 point
    It will be this spring / summer. Last summer there were a number of external forces that conspired to halt testing for 2019. I'm hoping this year I will be able to get more done.
  40. 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.
  41. 1 point
    Almost 2 months away from home, with little time to work on these boxes. One box is completely assembled and flush trimmed, needs roundovers and Duratex.
  42. 1 point
    Haven't EQ'D the skrams yet, but do have levels and time/phase lined up (I think) in the room with the other drivers in the room. Still running the skrams wide open. These skrams with the NSW are visceral, clean, and dynamic. I'm not an audio review guy, so I apologize for my remedial description. My ears and chest are highly enjoying the skrams. Thank you again Josh!
  43. 1 point
    Give it a shot. Tuning should be in the 15Hz range. Your sealed will probably only have an advantage below that point. If you went to 4 of them for extra headroom with the lowest tuning I don't think the sealed will have any advantage until very low in frequency. Likely below 13Hz or so. Depending on your room it may be more reasonable to use a tactile transducer setup for the really low stuff rather than throwing piles of sealed subs at it.
  44. 1 point
    OH MY GAWD!! WELL WORTH THE BUILD. These things pound!!!! FUCKINEH I will have my Powersoft K10 here next week and start to really set things up with tuning with a sound engineer friend from Meyer. THANKS RICCI & Everyone else that has contributed !!!!!!!!!!!!!!!!!!!!!!!! Notes from first build. 1. Don't rotate the mounting hole pattern, the handle will be in the way, making tightening 2 of the screws a slow process. 2. Don't install one of the side handles until the driver is mounted. Otherwise you end up hitting the inner part of the handle with a sledgehammer to make it fit because I used gorilla glue to put in the handles with and couldn't remove a handle.. 3. Don't install the handles with Gorilla glue, its a mess and squeezes out on the frontside. 4. Have a friend there just incase when glueing and screwing the final piece on in, mine was the bottom with vents attached and I could have used a hand to hit it with a block and hammer from the front to seat it proper as my arms are not 4 feet long and I had to run the screw gun on the other side. 5. Do apply liberal amounts of Sake to the process. 6. Bondo works great, so does the Gorilla glue, I used 2" screws on the perimeter, 1.75" on interior work, and a few 1.25" here and there. Don't know why I cant attach photos over .41 mb?
  45. 1 point
    It’s rated for 3/4” but you would need to run nitrogen to keep the wood from burning too much. I cut 1/2” at like 10mm/sec.
  46. 1 point
    That's gotta be the cutest thing I've seen all day! The smell in the shop must be horrible thou 😅 Making small scale models would require using a tiny router bit. That laser surely is a handy thing. If you now put a 6" (???) driver inside and made a working cab you would make my day!
  47. 1 point
    Godzilla: King of the Monsters - Dolby ATMOS (7.1 channel bed) Level - 5 Stars (112.7dB composite) Extension - 3 Stars (19Hz) Dynamics - 3 Stars (24dB) Execution - TBD Overall - TBD Notes - Loud, but not deep. Very much like Pacific Rim in the rolloff slope. BEQ for this film in the BEQ thread. JSS
  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
    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.
  50. 1 point
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