Jump to content

Leaderboard

Popular Content

Showing content with the highest reputation since 08/13/2021 in all areas

  1. Have a bit of an interesting field use report for my Skrams. I recently added new processing to my system using an XTA DPA 100. It’s a pretty interesting 4 channel amp, which I am using to bi-amp my Danley sh46 cabs. It also featured 4 channels of output control to add processing to my slave sub amplifiers. I used the information within this XTA/MC2 document on limiters to set up protection on my sub amps. https://audiocore.wpengine.com/wp-content/uploads/2018/05/XTA-Application-Note-DPA-Amps-Limiter-Settings.doc.pdf using the chart within this document it says to set up the 21sw152 at 86.9 volts for limiting, minus 1db for safety margin. Having always been a little hesitant on knowing just how hard I can safely drive my Skrams I added a 2 wire thermocoupler temperature sensing system to 1 of the cabinets to monitor magnet temperature. 1 wire is mounted on the external circumference of the magnet, the other right next to the vent on the end of the magnet body. last night I provided sound for a local dubstep crew, 7 hours of continuous deep sine wave bass. Peak volume was held for about the 3 final hours of the night, at maximum I was running about 2db down from where limiting would engage. Monitoring throughout the night, magnet temperature peaked at 44 degrees Celsius. This was also in a packed sweaty room that was raining condensation from the roof. pretty interesting to get some real Information about what the drivers are doing deep within the skram cabinets under real world conditions. I had previously come across a statement from Bennet Prescott who works with B&C saying that the 21sw152 can sustain 100 degrees magnet temperature without thermally damaging the coil. Previously I had been limiting these drivers to around 50 volts, it seems that in the Skram alignment we should be able to safely push them beyond that a bit without getting too much temperature build up. This of course may change for other types of music, I will continue to report back when I can speak to temps I’m seeing when doing other types of music shows. Data is beautiful. Always a pleasure getting to flex these cabinets, in a town where double 18’s rule, the Skrams are raisins eyebrows and making lots of new fans.
    5 points
  2. Had a pretty good outing this past weekend with our 4 Skrams and 2 Keystone subs for a 400 person event! Skrams are running off a Linea research 44m20. Tops are a pair of PM90 mid-highs which we just completed and powered by custom Hypex amps with a Linea Research ASC48 for sound processing . Was extremely limited on speaker placement because of the low tents and would have liked to run the Skrams on their sides or separated them slightly to spread out the coverage. Once we retire the keystones I think we may need to build another 2-4 Skrams to keep up with the Midhighs for bass heavy music but really impressed with the output overall! Got a lot of good feedback regarding the sound and people really appreciate the change from the usual PK cx800 double 18 subs that have over-saturated the market on the BC west coast.
    4 points
  3. Being a dual SKRAM owner and using the B&C 21SW152 for the last 1.5 years in this setup, I agree with Jay's description of how they sound. They are simply too brutish and over excited the room even at lower volumes. - This is in my 2 car garage/workshop. They are War Machines, these things kick ass and people take notice immediately. When paired with the right tops, like the Danleys or Meyers in my case, you're going to rock the house. If I was to build a system for in my house, I'd go with the BC 18SW152 in a dual setup or something much much lighter. The 21's are just too much and there sound doesn't really fit properly in a small space. (Coming from a Strictly Bass Head Opinion and not a home theater guy opinion...yet) Tops usually are not pointed so far down, was in backyard
    4 points
  4. With bass size is king. Comparing the Skram or any other cab to another random bass cab is really not that useful...Unless the data is good for both and other factors are taken into consideration. Size, weight, cost, complexity, intended frequency bandwidth, etc... All I know about the Dev style cabs is that they seem to have been inspired by my designs like the MAUL, Skhorn, etc...That's fine. No big deal. I was in no way the first to do this style of cabinet either. There is plenty of prior art in professional designs for sure. It is really difficult to have a genuinely new development in speakers unless it's in the digital domain. Anyway. They seem to be popular and there's a crap ton of flavors of the same basic thing. Most of them are MUCH bigger than the Skram. I have no idea how refined these are, or which one you are comparing to. Are there good quality GP measurements available? PK CX800 is really popular. It's just a vented sub that uses good drivers (18Sound 18NLW9601 units). Nothing ground breaking there, just solid components and design. Regular old vented still ticks a whole lot of boxes when done right. Especially if you start looking at output vs size. Vented will give maximum output at the LF corner in most scenario's, but will give up output in the rest of the frequency bandwidth against other types of designs of the same size. Output vs output I'd hesitate to speculate on too much, but if I had to guess I'd say they will be fairly close. The CX800 might win near the vent tuning depending on the port geometry and the Skram may win in the kick drum region but without measuring both at war volume it's hard to be definitive. CX800 should have more thermal handling just due to 2 drivers vs 1. This cab is bigger, heavier and more expensive than a Skram though. The biggest difference may be in the character of the sound rather than just output. Direct radiating sounds a bit more dirty generally speaking and a lot of people like that. People love to bench race subs but there's a whole lot more to it than output on a simulation. Hell this is part of the reason DB exists, was to show just how flawed a lot of these simulations and assumptions were.
    3 points
  5. Yes, a synergy type horn or for patent sake, a unity horn. I don't have a link to it because I didn't bother to make a build thread. It's my own mix of ideas based on Art Welter's SynTripP, B. Waslo's spreadsheet and the input of Chris A. on the Klipsch forum. I've built two cabs with 12" drivers and finishing up two more cabs with 10" drivers. I didn't port any of them. It seemed to me that 4 drivers would have enough clean output with moderate EQ without having to deal with ports. I'm very happy with the results. I'm using the Eminence TexTreme CD crossed around 850hz. It's certainly usable a little lower but to my ears it's a little less "honky" at high output.
    3 points
  6. Sed, Winisd isn't very accurate. It doesn't include inductance effects for subwoofers. It also doesn't include baffle and directivity effects. Sealed cabs are very easy. There really is no tuning. Put it in a 23x23x23 cube and power with a big amp. It is very hard to damage this driver. Look at the testing done here on the systems page. Note the voltage used for the maximum level output sweep. Pick an amp that can provide this voltage or under. Done.
    3 points
  7. I was running about 20% down from where the start of the limiters would engage during the headliner slot, so yeah lots of headroom remaining. I feel like I’ve had some breakthroughs this summer with tuning, I can get things sounding real full and impactful without it ever feeling tiring or abrasive, it’s a real pleasure to listen to. Open invite dude, I’m a big fan of alien technology, let’s set up a play date another clip recorded from the mezzanine upstairs, notice the bass warping the video recording…. Some serious pressure going down https://youtu.be/_Y7Y0FqIJfw
    3 points
  8. By "lack of cone control", do you mean non linearity in the translation from electrical to kinetic energy or do you mean cone flex? The former can be remedied by a stronger motor, the latter through a stiffer cone. Both problems are challenges to the designer, not to the end user. Any properly designed driver will play predictably based on the Klippel graphs. For B&C drivers I think it's the Xvar value, which is a general rule of thumb for when the driver behaviour will transition into non-linear territory. If this was a huge issue, big drivers wouldn't be so popular.
    2 points
  9. Just unloaded the wood for my 2 SKRAMs, starting the build on Thursday... oh boy 😻 Unfortunately I don't have access to a CNC router so I have go with lamellos instead. When it's finished I will probably reinforce some critical edges with glass fiber fabric & epoxy resin. That has to do for now...
    2 points
  10. PM90 by Peter Morris is a well designed and well reviewed DIY top cab. If you are looking to build something. Not cheap but you know how that goes.
    2 points
  11. @Ricci I think the stacking problem of your initial post has not been solved yet and I was just searching for corner protection and stumbled upon those https://www.thomann.de/de/adam_hall_4071_cabinet_corner_plastic.htm Me and my slight OCD find them much more elegant than trying to make stacking edges because they look much less asymmetrical, but if you want to go for them it should work as long as two neighboring edges have negative patterns, even if you rotate them. Just take a look at this very professional diagram that I made to understand the principle of those corners because my brain somehow refuses to think in transformation matrices. I hope it will work without math but I hereby declare that I won't take any responsibility for resulting damages 😂
    2 points
  12. Wow, dedicated MBMs with Skrams and horn loaded tops! Do you even need those? That's a lot of upper bass.
    2 points
  13. Hello everyone! A few days ago we pulled the speakers into town and enjoyed a little bit (some yes some no) unfortunately I didn't have time to do the measurements, but the only thing missing were two more boxes :D The difference between these two sounds is in the years. Tms4 are 35 years old and still work impressively, far from being loud for "today's standard", but during that time, respect 🙏 The kicks were modified BPH with 18Sound and Skram with RCF. Other sound are scoop from Rog 21 'loaded w B&C , Kickbin C2D-15' w B&C and the top box is not finished and loaded w 18Sound. A comparison between these two box. Scooper have more SPLs and up cut off i higher than in Skram, but for my ear Skram is much more tonal and works better overall, for some people scoop is better, they don't have the depth that Skram have and these days I'll switch them to DSP from K10 and make my cut off freq. and do comparison again hopefully outside w measurement, because now are connected to Ligwa Preamp (only Skram).
    2 points
  14. Maybe they defined their 'THD' as the sum of only 5th harmonic and up Manufacturers do all kind of crazy stuff to show impressive numbers. Like Klipsch, defining maximum SPL with the conditions "2 subwoofers used in 1/8th space".
    2 points
  15. Lots more killer setups in here since my last visit! Ive now build my 4th, which is the wonkiest so far and somehow the port sizes on the 2nd pair ended up different to the first pair but its not bad enough to notice too much of an audible difference at a party. Also got access to a new warehouse to store them so I can finally play around with positioning and tuning and whatnot, this along with my new amps for the tops has taught me that I need at least 2 more haha. Next party will be at the beach in a couple of weeks, before a big one for new years which im very excited about.
    2 points
  16. The ds and sw are very similar in maximum output at their respective program powers. Bennett from B&C said you should only really use the sw if you need the higher power handling, otherwise it doesn't really matter which you pick so you should go for the cheaper one. Here is a hornresp of different drivers I've compared in the SKhorn
    2 points
  17. I have them loaded with B&C 21ds115-4's. The soundsystem will be primarily used for small to medium sized outdoor parties where we might not always have adequate generator power so i figured the extra sensitivity of the 21ds115's might come in handy in certain cases. Although from what I understand the 21sw152 will go aprox 2-3db louder before power compression sets in? We also considered the new Eminence drivers however they seemed like they would be even harder to power properly in order to get the most out of them. The 44m20 amp has been absolutely incredible to use. I reckon it could power 8 Skrams in a pinch. We were using a Morin k30 before and although it had plenty of power it was extremely hard on our generators. The Linea seems to be much more efficient and also there was a noticeable improvement in the tightness of the bass produced. The linea amp also limits it current draw to match the power source which has been super handy as well as integrating seamlessly with our Linea ASC48 in System Engineer. Also wanted to say thanks for all your hard work and time you put in to sharing your knowledge and designs with us! This whole project has been extremely fun and rewarding and wouldn't be possible without resources such as these.
    2 points
  18. Should work out well then. Yes foam is perfectly fine. Cut to shape but oversized and stuff it in there. Yes it will be a tiny bit lossy. It doesn't matter. No need for wood blockers unless the foam makes your OCD trigger. My top pick for these is still the NSW6021-6 Eminence, but the Lavoce should do fine. The Eminence gives some advantages in response smoothness, ultimate headroom, distortion and compression performance but at increased cost. Unless you run them hard enough to start straining the Lavoce or 21SW152-4 driver most of that will not come into play though. In a home? Not so sure the extra guts are necessary.
    2 points
  19. Hahaha. Use the volume control fellas. I say go for it and run 2 in the house. Plug a vent or two for deeper tuning since you will not be using all of the headroom. May as well go for lower extension. I would pick these over the Othorn. Yes if you let a pair rip in your home it will be a bit much. What I often find is this type of sub sounds clean at volumes most others don't, so you end up turning them up higher than usual because it just sounds good/effortless/fun compared to a typical home sub. This gets out of hand quickly in a small enclosed room. I tend to like going way overkill and use <50% because it ends up sounding so clean. Plus if I ever want to get stupid it's there on tap. Disagree a bit on the 21SW152 or other big pro drivers not being able to do nuance.
    2 points
  20. I have a fairly small listening room at home as well and at one point I had a pair of skram's with sm60f set up. They were pretty exciting for certain types of music, live music recordings in particular were really incredible. I wouldn't have kept them in there though, they were simply too brutish and over excited the room even at lower volumes. If you do try this I would recommend using a different driver than the 21sw152. I think somewhere in this thread someone made some listening impression comments on various drivers and the 21sw152 was characterized as darker sounding compared to some lighter cone options. The 21sw152 is still one of the top drivers for war volume applications, but I think there would be better options for low volume listening.
    2 points
  21. This is a great room to play in, its been properly sound treated due to it being a live music venue. This system crushes in this space
    2 points
  22. Skhorns in Norway...Nice. Thanks for the video link. I would use the Eminence or the 21DS115 as alternatives to the 21Ipal in this cab.
    2 points
  23. I've finally built my first self- designed subwoofer. I decided to go for the 15DS115, ~90L net Volume and big ports with 3D adapted flares. The difficult part was actually to make the front small enough that the ports fit within the depth of the speaker, while trying to get as much flare area as possible. A simple 40mm flare radius would have made the front much larger. Tuning was more or less a blind shot. The vents were removable and I tryed 3 different lenghts before they and the back panel were glued. As I ran out of time, I measured just some short sweeps in REW, trying to tell the tuning frequency from the SPL and phase graph and then cut some cm off the vent pipe Tuning should be somewhere at 38 Hz now, but that's just what I can tell from the Rew measurements. I put more than 90 hours into the design, but therefore it is a n enjoyment to put all the parts together and see how perfectly all of it fits. I havn't really tested them to their limit, they are way to overpowered as monitor subwoofer, but I'm looking forward to hear and mwasure what they are capable of. https://www.dropbox.com/sh/frit8jmum8ptds3/AADfJ97ODnKO5Y4Gz1iBtawva?dl=0
    2 points
  24. This is the whole rig for now, I don’t think I’ll be adding anything more until we see what the future looks like…. Fucking covid. It’s perfectly balanced as is, I’d need more danley’s to keep up to more Skrams so the next leap would be expensive Haha. first time running it in a block like this, we melted some faces off, bass for days holy shit https://youtu.be/Bp4opVAjbZ4
    2 points
  25. Yeah it's heading back toward lockdown quickly here. I've already had a tour (performing not doing sound) canceled and a few spot dates with other bands that are likely to be canceled. Tour was billed right when things opened back up and reversed direction almost immediately. I've got a lot of friends who work as stage hands, or sound engineers and it's been devastating for them. It's a tough time to be a performing artist, bar or sound provider. Hell any type of person who makes a living from public gatherings.
    2 points
  26. Cone flex can be a problem but only in drivers not designed adequately for high pressure applications. It has not been a problem with any of the cab designs I've made/tested/used with 18" or larger drivers. There is a reason that modern high power sub drivers have a heavy mms and stiff suspensions. It is required for strength, control and power handling. The cone on a larger diameter driver must be stronger / thicker than a smaller diameter unit, the voice coils are massive to handle large power inputs, the suspensions are stiffer and heavier to keep things centered and prevent overshoot, fight against gravity over time, etc. Most pro audio and car audio subs are built to take a lot of abuse. This is why a pro audio 15" woofer might have a MMS of 80g but a true subwoofer might have an mms >250g. Even though the 2 might have a similar FS and Xmax rating or even power handling, they are still suited to different jobs. The 80g 15" woofer is not going to fare as well in a FLH or other high output high pressure loading.
    1 point
  27. You mean dado joints like on this board? I use them mostly to make the assembly easier, since it's hard to get the position wrong when everything slots right into place. It doesn't help much with structural integrity unless you do like 10mm or so I'd say. I do 3mm too. Doing this without a CNC is a massive waste of time imo. I only drew a sketch on to the floor board when I built my Skhorn and went from there.
    1 point
  28. By saving a few bucks on drivers you'll end up having to bring twice as many cabs to a gig. You'll end up spending more on wood than you saved on the drivers. Plus having to haul more subs around. Definitely not worth it imo, not even taking the difference in sound quality into account.
    1 point
  29. 4X SI 24's will be very impressive if you go that route. They are great for moving huge amounts of air effortlessly. I use the RF 19's specifically based on the engineering and quality of the driver and the objective measured performance of it. Has nothing to do with the brand RF. All of that data is available in the measurements section of the main Data-Bass site. My cabs at home are 4x sealed dual opposed. About 24.5x24.5x36" from what I recall. It's been a long time since I built those cabinets. Each driver sees about 4.5cu ft or 127L air volume. The MAUL is a quad opposed series loaded 6th order bandpass Frankenstein monster. Roughly 14.5Hz vent tuning. 47x47x30". 1086L net. 550lbs estimated. Response of the sealed RF's in my basement HT is attached. Subs only, at the main LP, no EQ, no smoothing, 100Hz LPF. You can see the 42Hz room mode caused by the room acoustics and seating position (center room). Cleans up quite well with a few bands of EQ.
    1 point
  30. AUS pricing for audio gear has always seemed crazy to me. Is there no authorized dealer for B&C / Lavoce / 18 Sound etc in AUS that maintains stock? EDIT: A quick search didn't bring up much. The B&C website lists one distributer in NZ but their website doesn't inspire much confidence. Mostly looks like a rental outfit for events.
    1 point
  31. SW and DS will be better than the SBA in every regard. You'll probably lose like 2dB going with the SBA. If you don't mind saving a buck I guess they're fine, but as soon as it means bringing 4 vs bringing 6 cabs or 6 vs 8 I'd say go with B&C, even if they're twice the price imo. How much is the Eminence in Australia?
    1 point
  32. The BC SW152 is about $100 more dollars than the SB. DS may end up being the same price. I dont know the pricing for the BC DS model though.
    1 point
  33. I'd recommend the $30 JBL driver under your couch/sofa as another option worth perusing. Being across the pond, not sure if you have access to that driver and/or at that price, but many use them on avsforum. Think they call it BOSS setup or something similar. Edit: it is indeed boss - back open sub shaker on AVS
    1 point
  34. Add first and then subtract later. Or subtract first then add later. It’s all the same in terms of maths. for a commercial product that you were trying to sell you probably do want to show that it has good bass response and works well in many rooms so you’ll probably need to boost 1st to target your Anechoic response (-3dB/-6dB/-10dB) etc. and allow user to EQ for good in-room smooth bass response. For your own use no need to worry about that. Just plonk it in for desired room; take measurements at the listening position and EQ it to your taste. if you are using it in theatre with multiple listeners, use of multiple sub place throughout the room may help smooth out the bass response.
    1 point
  35. 1 point
  36. You can use an LT circuit for this or regular dsp EQ filters. You will need to be able to take measurements of the subwoofer in order to develop EQ that modifies the response in the manner you want. Without measurements of the sub you are somewhat shooting in the dark. You can use simulations of the sub system to develop EQ but this will usually be in the ballpark only. Also keep in mind that EQ for flat response outside will often result in excessively boosted low end once the sub is placed in a room. Again measurements of the sub in room help a lot. If you want to play around with filters REW is free and has a robust EQ function, plus the ability to take measurements of course.
    1 point
  37. To wrap up here are some comparisons. AXI2050 vs 2445H both on the 2360A horn. Impedance. Both are nominally 8ohm drivers but the AXI2050 has a much higher avg impedance. Response and voltage sensitivity. The 2445H shows higher sensitivity, smoother response and much more extended high frequency response on the 2360A horn. Maximum level reached during testing. 2445H is with 15.9 volts input and limited to 400Hz to prevent damage. AXI2050 measurement is at 22.5 volts and starts an octave lower at 200Hz. Despite the higher voltage during the loudest measurement the output of the AXI2050 still lags behind the 2445H above 5Khz. THD during the above measurements. NOTE: The JBL was receiving 15.9 volts. The AXI2050 was receiving 22.5 volts. In general the AXI2050 has lower distortion. Keep in mind it is producing higher output below 3.5kHz and less output above 5kHz. Reference the graph above. 2.83v THD comparison. The AXI2050 is showing lower distortion but, note that at this input level the 2445H is producing more output above 500Hz. Reference the 2nd graph in this post. Output compression observed at the maximum output level reached. 15.9 volts for the JBL 2445H and 22.5 volts for the AXI2050. Again keep in mind that the AXI2050 is taking more voltage and it is producing higher output below 3.5kHz and less output above 5kHz. Reference the graph above. The AXI2050 is exhibiting much better and more uniform behavior here. The 2445H driver and 2360A combo exhibit some strange behavior in the 8-16kHz octave in this test. Most likely related to resonances and response shifting.
    1 point
  38. Measurements of the AXI2050 on the Klipsch K402 horn. Measurement sweeps at increasing voltage. Note the 22.5 volt measurement cuts off at 300Hz. The same data normalized to show only the compression of the output as the level is increased. THD captured during the measurements. Distortion harmonic makeup at 2.83 volts Distortion harmonic makeup at 22.5 volts Horizontal response. Vertical response
    1 point
  39. Impedance measurements of both JBL 2445H CD's. Overall the matching of the drivers isn't bad considering their age. Unfortunately Mounting the 2445H to the K-402 would've required cutting into the mounting bracket to clear the magnet diameter. I didn't feel like taking that step. Impedance of both 2445H CD's loaded on 2360A horns. Impedance of one of the 2445H CD's without a lens and loaded to the 2360A. Impedance comparison of AXI2050's. AXI2050 impedance with no lens vs loaded onto 2360A AXI2050 impedance with no lens vs loaded onto K402 AXI2050 impedance on K402 vs on 2360A 2445H vs AXI2050 raw impedance 2445H vs AXI2050 both loaded onto 2360A horn
    1 point
  40. I've not actually tested or listened to the Skram yet. I do have a pair of Skhorns which should sound very similar in character. I sold my Othorn's awhile back. I do prefer the Skhorn / Skram sound. To me it is slightly more clean, more flexible, easier to build, smaller and can avoid some of the resonances that show up in TH's. I spent a lot of time trying to clean these up in the Othorn design. TH's can sound very good and the Othorn was the best I've heard or seen measured. Every sub I design has priority #1 of low distortion, high headroom, high damping. Those aren't always complimentary goals. They aren't always easy to accomplish with high order designs either. As far as drivers go the best ones are expensive. Most of what I design requires them due to the priorities and attributes chosen. Any old driver will make noise in any cab but there's a reason I only recommend ones I'm confident will perform like the sub is intended to.
    1 point
  41. Wow, these are nice! If I may make a suggestion for the comparisons of power at different frequencies: plot these in units of dB instead of watts! Use 1000 Hz as a reference, so it's always "0 dB" at 1000 Hz and will typically be small or negative at the other frequencies. (So maybe use "+1 dB" for the top of the Y-axis.) I think this will convey information that is much more useful to the reader as it clarifies exactly out much output you lose at some lower frequency. The formula to calculate this is as follows: dB(f) = 10 * log10( P(f) / P(1000) ) where dB(f) is the decibels at frequency 'f', and P(f) is the power at that frequency. dB(1000) should always be 0. Other graphs may also be more useful in decibel units, but decibel units only make sense when you have a meaningful reference point as above. When comparing different amps to one another, there isn't a good reference unless you choose one of them to compare everything else to. What do you think?
    1 point
  42. This is freakin awesome LMAO. I'm jealous of this setup.
    1 point
  43. I am in North Lake Tahoe, Truck is stored and worked on in Truckee. We rollout to the Black Rock Desert or a couple spots in the woods. You are in Canada? Would love to combine forces!
    1 point
  44. Well said tahoe, the overbuilt heavy and robust 21sw152 is meant for high power mayhem, at low volumes I wouldn’t consider it delicate and nuanced. I’m currently using a direct radiating reflex in my living room using a light weight high sensitivity driver and it’s much better suited for the size of the room. Even at low to moderate levels the Skrams were knocking plaster off the roof of my living room, the design is just not meant for home use in my opinion. Perhaps a lighter duty more efficient driver in the skram could work really well in your situation but I don’t have the experience to back that up. where is this war machine truck of yours Tahoe? We should meet up and let our Skrams have a play date haha
    1 point
  45. I'd say you have a pretty good overview already. I have 4 21ds115, but if you want some 1-2db more headroom, go for the Eminence. Your call if you wanna spend the extra on that. For me (in Germany), the Eminence is twice the price than the 21ds115. It's actually almost the same price than the 21IPAL here. In the states it's more like 500 vs 700$ between LaVoce and Eminence I think. I'd personally go for the latter there.
    1 point
  46. Graph above shows THD at various voltages. Starting level = 2.83 volts Ending level = 22.5 volts
    1 point
  47. Outer dimensions are 43x58x65,5cm so ~164L. I think I could have lowered the net volume (~90-95L, B&C suggest 80L), also at the cornes I loose a little volume, but as mentioned, the limiting factor was the port lenght and to fit it inside the cab without to bend it while letting the front big enough for driver and vent flares. Some other facts about the cab: The "main" front is 30mm, plus 15mm added under the driver cutout to have enough depth for the 40mm Flare, and another 15mm at the backside of the front, as reinforcement for the driver (30mm-20mm would have left just 10mm for screws) and as pipe-holder. (this one was meant to be 12mm, I just didn´t think about it and used 15mm instead). So at the thickest part, the finished front is 60mm or 2,36" thick, yet it wasn´t that heavy, obiusely because the front is mainly just three holes rather than remained material. All the other parts were made of 15mm MPX, but as you can see, i didn´t skimp on brazings, so the cab should still be pretty stiff.... I hadn´t time to put it on a scale yet, and this one isn´t a lightweight for sure, but at least, a single person is able to lift it up and put it on a wheel board. I will post measurements as soon as i have time to make some. The ones I did to test tuning frequency were really dirty (no fix mesaurement distances and even bader, a back panel that was hold together with clamps, as I had to be able to remove the pipes through it to make them shorter). Actually, I always made a ~2m ground plane measurement and another one at the outlet of the port. With the second one it was pretty easy to determine a tuning frequency, although I have no idea how close this one comes to an impedance measurement. Honestly, I don´t even know why it´s important to know the exact tuning, or how I can find the optimum, but the measurements showed some dB more around 40Hz with the shorter port, still there was enough low end in the listening test. The great thing is that the ports are so big, that it should be ok to close one of them for small gigs or a home theatre show at home, tuning drops down to ~25Hz with one port closed.
    1 point
  48. Jay how many of these do you have built now? 8?
    1 point
×
×
  • Create New...