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Showing content with the highest reputation since 09/28/2021 in Posts

  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. Hello, If you ever use this setup again, you shouldn't use the mini scoops and just cross your Skrams way higher. If those BPHs are ES18, you can (and should) probably cross them at 80hz directly with the Skrams. Using 3 boxes for the 25hz-220hz seems counterproductive to me, especially if you didn't put them properly in phase. If you build 2 more Skrams, even if the boxes don't have the same drivers inside, let them play together, the phase should be pretty similar, you will win more than using them crossed separately
    2 points
  7. Hello ! Took me a while but I finally remembered to save my measurements to share those with you. They are worth what they are, I'll try to get unfiltered ones the next time. So here is an uncalibrated measurement of 2 Skram units, 21DS115-4 loaded with a 2nd order BW filter at 24hz and a 4th order LR filter at 108.8hz. (No correction EQ). The subs were 8 meters away. Considering how flat it is with the LR filter, you can imagine how the curve is rising after 50hz.
    2 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. Hello DJimbo and welcome. As far as assembling the cabs go. Clamps and more clamps are your friend. Other options that help are a brad nailer, or a pocket screw kit. If using the 21SW152 drivers best results will probably be with 2 to 4kw of amplifier rating per driver. Any more might get sketchy over long periods of time. Less would leave some of the dynamic capability on the table. I prefer to run fully bridged amp channels on bass when possible. Smoothing out the corners might help with airflow in an ideal scenario but it has drawbacks. It reduces the internal volume utilized by the driver. With bass size (air volume) is king. The Skram is a vented cab on the back side so it's a traditional ported arrangement there. Large flares and circular vents would be beneficial ideally but would greatly increase the size of the cab and its complexity. The front is a short horn/expanding slot. The same applies here. Ideally it would be a totally smooth, straight path, but packaging it into the cab dimensions requires compromises. At best these would be small gains in output / noise reduction, even if it was built ideally with a totally different (much uglier and unwieldy) form factor. I hope this explains why most bass cabs do not bother with dramatic smoothing of the air path. It comes with other tradeoffs.
    1 point
  24. Hello again! I don't know what the weather is like in your place, but it's still hot here in Croatia. A week ago we took the sound system out to the festival, but unfortunately we didn't have 4 SKRAM as planned. Otherwise, what I would try is that the lower SKRAM work from 25HZ to 60HZ and the upper two from 60HZ to 110HZ.. Why is that, since in one box we have 21B&C SW152 which would be for the lower range and 21RCF N551 which would be for the upper range(personally). Normally, we'll try how it would be if both boxes worked at the same frequency range and one more thing we didn't try is to close two more output ports from the lower SKRAM to get the depth, even though they still go quite low and sounds nice. Currently, as you can see in the picture, instead of SKRAM, we put mini scoops that did a great job. I can't wait to do it , listen and measure the boxes to see what happens with the phase between the different drivers and how its sound overall with 2 more but I think it will be much better because as Ricci said, it is better to have more same boxes like this that work the whole range from 30 to 110HZ than for example like in the picture with mini scoops. I need to hear that combination to be able to make a comparison but I think it will better w SKRAM since there are no different boxes although this was very mellow tight and clean Other two almost finished ! SKRAM 21' RCF N551 (25-55) "MC2 E45 Bridged" MINI SCOOPS 18' 18SOUND LW2400 (55-105) MC2 E45 Bridged BPH 18' 18SOUND LW1200 (105-220) "MC2 E25 Bridged" F1-DS210 (220-18K) "MC2 E15"
    1 point
  25. Hello Ricci, I had the opportunity to get some fresh measurements this week-end. The 2 skrams, 21DS115-4 loaded, were superposed horizontally, mic on the ground at ~3 meters. I did measure one cab (the one sitting on the floor) and two cabs. No LPF, my HPF was set at 19.7hz (as low as my processor was able to go, I think it was a -24dB BW but looking at my precedent curve I may have put a -24dB LR by inattention which would explain the slighty higher -3dB point on those) These are still uncalibrated btw ! Green : 1 cab | Red : 2 cabs
    1 point
  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. Finally spent some sheckles to have a proper power panel build to run my amps on 240v which isn’t super common up here in most venues. While subtle, things felt a little cleaner and tight and amps ran noticeably cooler. We knocked some bottles off the wall of the bar which was a first so it seemed to have helped https://youtu.be/rqMiTLL15s8
    1 point
  28. 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
  29. I'm pretty happy with my 21ds115 powered subs (similar to the Skrams I guess, just a bit smaller) and l-acoustics ARCS wide tops. PM90 components are obviously top of the line, but I personally prefer scalable solutions (the ARCS wide can be used as single 90x30° loudspeaker or in a fixed curvature line array with ARCS focus (15°) speakers). PM90 won't achieve uniform audience coverage over a large area, but it'll do exceptionally well for small clubs or small outdoor shows. Or when you just want higher SPL closer to the stage.
    1 point
  30. The PM90 would be my go to choice if I was doing PA for a living on a budget. Other than Peters Line Array I would say its the best sounding speaker I have heard in a PA lineup. I got to hear it compared to a 10ft tall Krix pro cinema speaker and it sounded quite similar at 1/4 or less the size. PM90 only goes down to about 120hz but that is a lot of fire power in a small package. Sadly I havent started building my Skrams yet due to pricing of lumber and divorce. Hopefully will start towards the end of this year.
    1 point
  31. the worst is that in 2022 prices skyrocket high and salaries have not. that su.... big time. how many watts you need to feed the skram's, and what is the headroom you need to have .
    1 point
  32. iirc the LaVoces were in a parts express deal for 400 flat or something, 3 years ago. I paid 410$ for my 21DS115's. Now they're around 650. That's up over 50%... Imo it makes no sense to build the Skrams if you intend on putting non ideal drivers in it. A good subwoofer is a good subwoofer, but that's the entire system of driver+cabinet. Even if the cabinet design is stellar, it'll make a bad subwoofer if you don't put the right driver in it. That's also how DIY got a bad name over here. And just outright bad designs of course. Build something else if you wanna use other drivers or design a simple vented cab if you have a specific driver in mind. Designing a vented cab with a slot port is really simple.
    1 point
  33. Just this little thing https://data-bass.com/#/systems/5aa4a25261feb10004121e18?_k=qak9b2
    1 point
  34. 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
  35. 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
  36. 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
  37. 1 point
  38. 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
  39. As some of you probably know I switched out the top end of my big warehouse system a long time ago. I went from JBL 2445H's on 2360A's to Celestion AXI2050's on Klipsch K-402's. I took a bunch of measurements but never got around to posting any of it. I'm not going to devote too much time writing up a big break down of all of this. The short version is the K-402 horn is an overall improvement over the old JBL 2360A in most ways. The JBL does offer better loading down to deeper frequencies, but has more acoustic issues overall. Resonances etc...Physically the K-402 is slightly, smaller, lighter and less deep too. The old 2445H CD is not a cutting edge design any more but it is surprisingly viable still. The AXI2050 is considered cutting edge and it does offer some intriguing benefits, but it isn't all wins against the relatively ancient 2245H (or other more conventional 4" CD's). My short take on the AXI2050 is this: It offers excellent lower midrange performance with the possibility of really using it XO'd down to 350-400Hz (with less than full out pro use SPL and duration), or 500-600Hz at full on pro / arena use levels and depending on the horn/ waveguide used with it of course. Coupled with large horns such as these, the SPL and distortion results in the lower midrange are impressive. This driver does technically make it up to 20kHz but it requires a really healthy dose of EQ, even more than with most large CD's. The old 2445H kicks the AXI2050's ass in the top octave. The AXI2050 sensitivity and response above 10kHz is serviceable, but not great. Where it shines is in the 400-8kHz bandwidth. It measures well and sounds stellar in this range. Other options cover >10kHz much better with greater sensitivity. Even after EQing the top octave into shape it only sounded adequate. It wasn't bad but it wasn't anything to write home about either. The midrange on the other hand sounded great. Also this is a really robust CD. It will handle border line abuse that I'm not sure some other CD's would. In summary. AXI2050 = Killer midrange / so so top octave. I ended up switching to and keeping the AXI2050 because the midrange is way more important to me than top octave treble.
    1 point
  40. 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
  41. What Magico aren't saying is under what conditions that was measured or simulated. I looked but not exhaustively. The sub might do it in a car or a closet. 4000w = 36dBw Average sensitivity of sealed 18's I've measured is about 79-82dB at 20Hz. With 2 drivers in double the airspace it's maybe 85dB tops. It will increase a little with a much larger cabinet, but theirs isn't that large. They look to be using Aura based 15's and 18's judging by the pics. They may be modified but those are definitely Aura based drivers at minimum. Decent drivers for sure but no way in hell they maintain 1% distortion with any sort of real excursion being used. Even with active feedback. No way a sealed cab can make loud 20Hz noises without tons of excursion because physics. Unless...they are in a tiny confined space like a closet or measured extremely close to the cone, or both. When I measured the Aura 18 it would burst about 107.5dB maxed out at 20Hz with horrendous distortion. This is basically everything it has before something breaks. Add 6dB for a second identical unit on double the power. Call it 114dB rounded up. Subtract a couple dB to clean the output up and pass CEA-2010 thresholds and my estimate for Magico's Q Sub at 20Hz under DB style ground plane testing (2m groundplane, rms) is in the neighborhood of 112dB. Assuming the amp can push it that far. Definitely not with 1% distortion. Add 3dB for peak SPL. Add another 6dB for 1 meter results. The remaining 15dB must be from the particulars in the way the sub is measured.
    1 point
  42. 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
  43. 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
  44. The QSC sub is larger and probably has more vent area compared to the Skram (when you block Skram ports to reach the same ~25Hz(?) tuning), meaning the QSC will be louder in the sub bass. Skram is front loaded, which means it's more efficient (louder) in the mid/upper-bass region. Skram is basically a band pass, which means it also masks some distortion. That would be the 3 main differences I guess. Skram has a rising native voltage sensitivity, while the QSC is probably pretty flat, going by my gut feeling here.
    1 point
  45. This is freakin awesome LMAO. I'm jealous of this setup.
    1 point
  46. 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
  47. Sound quality wise, I'd take skrams over double 18's all day every day.
    1 point
  48. Contemplating replacing my very good 15"-loaded MicroWrecker tapped horn subs with a pair of Skrams in my home system. Currently I'm low-passing the MW's @83Hz 36dB/octave L-R, which seems to be the limit of their upper band before starting to progressively take on a specific and undesirable sonic character here. Conversely a lower cross-over to the mains yields lesser results as well, so 83Hz really is the sweet spot in my particular context. Still, being I'm so close to the MW's hard deck I'm wondering whether another sub design with a more cleanly extended upper band, like the Skram, would clean up some of the upper bass to lower midrange range, while also making way to experiment with a slightly higher low-pass up to about 100Hz or so. At its "native" tuning with all ports open the Skram doesn't extend quite as low as the MW's, which are tuned at somewhere between 22-24Hz it seems, but blocking one or two ports of the Skram offers a ~25Hz and ~20Hz tune respectively, and so there are ways to come about a slight limitation in LF performance compared to the MW's. Being that I won't be using the Skram's anywhere near their SPL limits port noise isn't going to be an issue, even with two ports blocked - or so I gather. Will two Skram's be overkill in a home setting? Sure, but I think of it as "the more headroom the better," or certainly it can't make things any worse. I'm interested in sound quality and clean visceral impact at higher SPL's, and maybe the Skram's will bring something else to the table that's complementary to the overall synergy of my system. Any thoughts on this speculated change are welcomed. /Mikael
    1 point
  49. What do you mean by low level? The last measurement was taken at 0dbFS, which produced 6,6V at the Fireface's output. Here is a direct measurement of the FF without the pmillett in the loop (max output 6,6V as before): Best THD is achieved at 0.5V output, best noise floor at maximum. Here is the THD/Noise vs output plot:
    1 point
  50. No offense to RF as they do have some sharp guys but the whole, driver optimized for sealed / vented / BP and don't use it in another alignment, is for the most part antiquated thinking from back before modern signal processing. There are drivers that are better suited to some jobs than others make no mistake, but this is not one of those. Usually the reason you will hear that drivers are not suited for sealed is the qts is too low (IOW too efficient) and without EQ it will be bass shy because the top end gains sensitivity quickly and overpowers the low end without EQ. In this case RF is assuming that these drivers are going to be used for car audio SPL comps and the like and ported will be way louder than sealed and will also handle high power inputs longer. I can see why they would recommend this for their statement competition driver but if the app is not putting up big scores in a Tahoe it's one of the top high power sealed drivers available. It's 2020 and unequalized frequency response is much less of a priority than it was 30 years ago.
    1 point
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