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Showing content with the highest reputation since 01/26/2020 in all areas

  1. 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 othe
    4 points
  2. Ok. I had a look in HR. It had been awhile. I'd recommend a 3rd order BW at 24Hz or a 4th order LR HPF at 21Hz. This is for operation with all vents open. 4th order LPF adjusted to taste for blending with the mains. Somewhere between 50-120Hz. 70-100Hz is probably what would work for most. The response looks quite good with just the high and low pass added. This is the response with the 21SW152-4. Most of the other recommended drivers are going to be close to this as well. If you want to take it a bit further You can add a single band of PEQ at about
    3 points
  3. 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
  4. Had my next party on Sunday on the beach with my 2x skrams and 2x Martin W3 tops running from an inverter in my Prius from 2pm till nearly 2am, averaged around 1000w into the whole system (including the CDJs and amps and a few LED lights) and used about 5L of fuel in the car. Around 150 people at the peak of the dancefloor, everyone seemed to love it! Definitely need to build 2 more of these things and upgrade to the proper drivers for even better sensitivity to keep up with the tops
    3 points
  5. 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 assum
    3 points
  6. 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, 21I
    3 points
  7. 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 f
    3 points
  8. 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!
    3 points
  9. Hey Josh. Curious if you would be willing to make a recommendation for high and low pass filters with recommended slopes your Skram design. It’s been a while since I’ve had mine out with the pandemic and all, but I’m planning a day at our studio tomorrow to get everything plugged in and spend some timing tuning and tweaking. Planning to get the measurement mic out and spend some time dialing in the system so I don’t get rusty haha. I’ve been happy with the setting I’ve been running which I don’t remember off hand but I’ve got some different amps on hand so willing to try some new things. Anoth
    2 points
  10. As far as testing goes. There is nothing happening right now and for the immediate future. I've had to turn away a bunch of companies and projects since this time last year and I'm still sitting on a whole summers worth of testing from well previous to that. I'm not planning to be done completely, but after 10 years my priorities and other life goals have shifted and I can't find the hundreds of hours to put into testing, and publishing every year, like I once did.
    2 points
  11. 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.
    2 points
  12. 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.
    2 points
  13. 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 the
    2 points
  14. 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.
    2 points
  15. 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
    2 points
  16. 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 quiet
    2 points
  17. @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 ~8
    2 points
  18. 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 th
    2 points
  19. Finally! Measurements coming soon. If the weather is on my side.
    2 points
  20. 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 bui
    2 points
  21. 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 sectiona
    2 points
  22. 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!
    2 points
  23. 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.
    2 points
  24. I've recieved an answer and they suspected this phenomenon was caused by bad contact of the speaker connector on the amp. I had the amps stored on a shelf in the warehouse for a few months, so it makes sense that there was some dirt build-up and corrosion-like effects (humidity never exceeds 60% there thou, so it's only minor), since the amps were unpacked. Running a higher current through the connector seems to literally clean it, which reduced the distortion. The more you know..!
    1 point
  25. No stress, I can dig through it again. I did play around again a bit over the last week and I think to my ears at least I still like 100 to 110 hz crossover for most music styles. If I drop it down to 80-90 I think it sounds a bit better for stricktly bass music, but for house and techno, rock etc I prefer it a bit higher. Then again its harder hearing it proper indoors. Depending on our pandemic situation when summer rolls around I'm pretty keen on heading out to crown land for a number of days just to work on tuning.
    1 point
  26. I'm in Adelaide. I have a pair of 21SW152's sitting on a shelf still waiting for me to build my Skrams. As long as you dont mind the long wait for shipping times there are better options that PE. But if you want it asap then PE is probably your best option.
    1 point
  27. Moving up and down stairs to roundover, sand, fill any tear out, sand and paint was a bit of a chore, requiring assistance of a hand cart, ratchet straps and a strong volunteer. Also, the number of good weather days were limited, coupled with working away from home a lot meant that I could not spend as much time working on these as I would have liked at a time. Second one is partially assembled.
    1 point
  28. Great pic of the sunset. Looks like a good time!
    1 point
  29. Whatever works...LOL! No judgment here.
    1 point
  30. Wow it's been a very, very long time since I've updated my thread. Life got really busy in the past few years and I barely could squeeze time to work on the speakers, so writing about them and sharing it got lost in the shuffle. I want to give a conclusion to this speaker saga and give way to a brand new small speaker design that is significantly better than the Reference Mini in every single way. I continued working on this speaker over the years, and really refined it as much as I could. In the process I realized this speaker's design is actually extremely flawed in multiple ways. Howe
    1 point
  31. 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 fr
    1 point
  32. Thank you for the time and effort over those 10 years. Still kinda struggling with the reality of complex induction and oem vs consumer availability for drivers. I want deep and clean. HT/Music/Automotive/Nature sounds for sleep. Will eventually reach out to Harbottle Audio for something underhung and nasty. Data-bass helped me understand why that is hard to find in the consumer market. Also understand why the price is north of what can be bought in a couple of mouse clicks.
    1 point
  33. I know some people have had issue with t nuts spinning. Here is what i did to ensure against that, small screws and a bit of epoxy I had on the shelf. Fairly crude but simple and will be effective..
    1 point
  34. 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 bett
    1 point
  35. I'm actually heading to our local makerspace woodshop this weekend to cut up panels for another 4 of these. I gave a couple of my music nerdy friends a demo and they immediately asked me to build pairs for them. For less than 1k Canadian you can build a pair with a berry nu3k included in the price. Unreal value for the dollar.
    1 point
  36. "The maximum output in dB is not very important. " But it *is very important*. It's always very important because it has by far the greatest impact on other trade-offs like size and cost. With that said, there are a variety of DIY and commercial options that can get you started, and you shouldn't have much trouble getting decent output for moderate music listening for the range you indicated in a fairly small room like yours. I'm reluctant to name brands because I'll probably leave out someone relevant, but off the top of my head, I can think of Power Sound Audio, Hsu Research, Rhy
    1 point
  37. 1 point
  38. Should be fine. They are more similar than different. This one just has much less path length and gain from the front section to keep the size down.
    1 point
  39. How well would these integrate with the skrams and skhorns if they are all overlapping the same frequencies? Asking for a friend...
    1 point
  40. Excellent job Josh on packing this much deep bass for such a small size. Just what the Doctor ordered. Two nearfield corner table CKRAMs coming right up 😱
    1 point
  41. Yes, my models of the pure vented cab and the RLH were exactly the same (except that the tuning frequency of the RLH somehow ended up higher, even when using the same straight ports, so I changed the back chamber volume to match the original vented sim). Particle velocity at the mouth was reduced by 50%, which might give me a db or two more output at maximum output levels. Making those ports was probably 10x the work of simply doing a straight port, it better pays off. Look, it's a potty!
    1 point
  42. Soon we will know..!
    1 point
  43. I would highly recommend reading the attached white paper that was written by Paul Williams on crossover filters and there characteristics. Paul is responsible for the DSP algorithms in Linea Research products. CrossoverFilters White Paper -C.pdf
    1 point
  44. I'm using the SKHorn in 1 port mode in my HT. I get no usable output below 18Hz (chuffing related), which is fine because I'm sitting on a tiled basement floor. Only TR I can get is from my mini riser. Use regular oval-head screws. I use those black ones commonly used for sheet metal, which work great on plywood too. There are gaskets for the handles which are less than a dollar (penn elcom) but you can also use 20x2mm gasket tape like I did. I like the screws, they make for a clean look.
    1 point
  45. The newer drivers with higher xmax and lower Qts lend themselves to compact 6th orders better than the drivers of old. IMHO. At least that's how I ended up on these during the MAUL design process back in late 2014. I'd like to think I had a hand in popularizing this type of 6th order among the DIY crowd and perhaps even the pro market (In this case it's probably a result of form following function). Among the DIY scene they sure seem to have exploded in the last year. There's always been 6th order variations going back decades though. Too many variations to count. There really isn't
    1 point
  46. 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
    1 point
  47. Nice looking builds. I like the big square slot port on the 21. You don't see those too often.
    1 point
  48. 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
    1 point
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