jay michael

15 hours ago, Father Francis said:

Question for anyone running four plus skrams, last weekend we were running 4 cabs standing strapped together with 2*215 , and a pair of F1 res3 sh , 

anyway after the gig the two cabs in the middle were pretty hot, the cabinets plywood like very warm , cabs are loaded with B&C Sw 152 8ohm running all four off a K20 

Hey Father Francis. Heat happens for sure, on gruelling bass music shows I can feel the heat on the metal of the hatch handles, and if you put your hands in the vents you can feel the warmth coming off the drivers. I've rolled mine out to the trailer in cold Canadian winter nights and seen heat causing a bit of fog to come out the vents haha.

There was some mention in previous pages regarding the potential for heat to be a problem for this cabinet. While you should be careful with your limiters, in real life I don't think its turned out to be as big of a concern as was warned against. I've been using a pair of thermocouplers to pull temperature data off the magnet, if I'm working them hard I can get temps up close to 70-80 degrees or so when I'm tickling my limiters during heavy bass music shows. Bennett Prescott from B&C stated that the 21sw152 should survive 100 degree magnet temps reliably, but I've made it a point not to run them that hot. I only really see that high of temps for dubstep or modern bass music shows, for most everything else temps never seem to build up when I push them to the verge of limiting. I've actually found this a bit interesting, as it was stated earlier in this thread that one should avoid pounding techno with this cabinet but that hasn't been my experience at all.

I specifically use this guide to set my limiters and I haven't burnt one up yet, its written by XTA but can be applied to any amplifier. Start at page 5 and follow the instructions closely.

https://www.xta.co.uk/wp-content/uploads/2018/05/XTA-Application-Note-DPA-Amps-Limiter-Settings.doc.pdf

Cant stop, wont stop.

32 minutes ago, DJimbo said:

Awesome shares yall.

I spoke with a rep of B&C about powering their drivers. Guy was insanely knowledgable. He said, "you want the absolute most powerful amps that are made to power these drivers properly"

He explained how power hungry these can be and how under-driving them is a bad idea. We discussed powersoft amps and Linea. He basically just shot down my dreams of being able to power these (6 or 8 SKRAMS) properly off of a 120v circuit, or even two circuits. Now I am a lamen when it comes to most of this so I am curious about yall's thoughts about this.

Like 21' drivers are sick obviously but if we are putting them in such a small box for their size we are cutting their balls off a bit. I guess I am stuck wondering if the LF extension of the skram is worth the extra amp expenses, powering issues, etc. when TH118XL's can be found used and are comparable in size and output (above low low freq's) according to previous posters. Id love to be enlightened on the skrams and anything I am missing here and I think our group here will find any reflections useful. Thanks!

Thankfully we live in the times of cheap and plentiful amplifier power. If you can manage without sophisticated control and monitoring you can find lots of options for  amplifiers that can easily turn these drivers into molten lava. Take a look at companies like Admark, Cvr, Wasi just to name a few. For as little as 8 or 9 hundred usd you can get 15kilowatt 2 channels amps that can push their rated power into long sustained loads and sound great doing it with solid reliability. Pick yourself up a nice dsp from Linea Research,  or one of the other leading brands and get a few of these amps and you will be loving it. Even on a 120 circuit you should be able to properly power 2 or 3 skrams without tripping breakers. These amps conveniently have power factor correction, so they will take what ever voltage you throw at them reliably

I really need to make an update to this video at some point, learned a lot since then and could offer a lot of clarification to this procedure.

Final form post! I’m declaring this the finished Ionic Sound System (I hope, haha).

Countless hours, more money than I’d like to admit and I couldn’t be happier. My garage is full, the trailer is maxed out, my truck is at its limit of towing capacity.

Josh, you have created something really special with the Skram design. The bass heads drool over them, live music kick drums sound insane, and techno beats sound clean, punchy and dynamic…. What else could you want? The perfect all rounder sub design, bravo! 
 

Headphones in! 

I second going for the better driver, more of an investment upfront but it will never leave you wondering what you are missing. Good luck with the build! I'm currently piecing together another pair.

1 hour ago, m_ms said:

 

When you say a pair of DSL SH46 "outrun" 6 Skrams, is that simply in reference to the total output the SH46's are capable of by comparison, or is it more of a "feel" for the energy-balance between the SH46's and Skrams in the sort of venue you're using them? I presume the Skrams are dialed in somewhat hotter vs. the DSL's and therefore also run out of steam earlier/need more headroom to keep up?

As a thought experiment, say you were using a pair of SH46's in a home environment in a moderately sized listening room (I know, overkill, but bear with me). Would 2 Skrams suffice augmenting them here, i.e.: provide a proper mains/subs balance, or would more of them be necessitated in such a listening milieu in conjunction with the DSL's? 

Lastly, is a single DSL TH118 comparable to a single Skram in output, even though the TH118 only uses an 18" vs. a 21" in the Skram? And in case, does the TH118 therefore make more effective use of a given driver diameter in given enclosure volume due a more outright horn-loading of the back wave of its driver, while also making use of the front wave? Both of them are high order bandpass designs, but the Skram is using a somewhat shorter "horn" loading..  

I think the combination of SH46 and Skram is just simply a great pairing sound and power wise. The horn loaded upper bandwidth of the Skram really compliments the sound character of the SH46, together they sound very clean with well defined impact, some would describe it as having "fast bass".  For an example, If there is a genre of music that I've heard sound shit on a lot of sound systems, its psytrance. Something about those fast upper bass notes just seem to show the warts on many sound systems. The Sh46 Skram combo sounds better on psytrance than anything else I've ever heard, F1, Void, Turbo etc etc. On top of that, one of my biggest rental clients is a long standing local crew that specializes in bass music, dubstep, drum and bass etc.  They like the Skrams so much they are now building their own. For reference, this same crew was previously a heavy renter of PK sound, which some people say is the yard stick for bass music subwoofer's.  So yeah, the Skram is an exceptionally flexible cabinet, it really can do all the things well.

To your original question, I would add that when my 6 Skram's start touching limiting, the Sh46's still have a few db of headroom to go. Personally I'd say the appropriate sub to sh46 ratio would be 6 to 7 skrams per pair of sh46. I've got another pair of SH46 on the way, with a couple more Skrams in the cnc cue, if I have another successful summer next year maybe Ill cut up another 4.

Th118 vs Skram, I think Josh would be a better person to answer that one... they must be fairly close in output overall, but I'm just speculating

I'm using the 21sw152. Sh46's can get stupid loud, especially when bi-amped. Two pair of them can cover 1500 to 2000 people for electronic dance music. While the Skram can really boogie,  its still a medium sized cabinet compared to other types of designs. Pretty typically for the Danley guys to recommend 6 th118's per pair of sh46, so I'd say my assessment is pretty accurate. This would be for heavy bass music mind you, for techno you could probably get away with fewer

My pair of Danley sh46 are a pretty good match for 6 skrams, but they still outrun them a bit. I think 8 skrams would be the perfect balance. I've got another pair of skrams in the cutting phase, and another pair of sh46 on the way. Lots of skrams popping up in my area, there will be 12 in my city pretty soon, as well as 8 or 10 on the island. Been some planning discussing how to get them all in the same place sometimes soon

I'm planning an after summer report soon, was hectic busy with lots of great gigs

6 minutes ago, Ricci said:

I do like 240v for running big / multiple amps. Just seems to do a better job in most cases. 

Speaker gasket tape FTW! I use that for the hatches, handles, drivers, etc...Always good to have on hand. 

Interesting experiment for sure. My personal take away is use 240v if available. If you don't have access you can still get solid performance from 120v plugs, just ensure you aren't overloading your amplifiers with too many speakers. On 120v I run 1 amplifier per 2 skrams on a 4ohm load and can achieve likely 90-95% of what can be achieved using 240v. don't expect to get the most of tough 2ohm loads from 120volt. Of course with 120v you will draw twice the amperage, deal with more heat and that may but extra strain on your gear.

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

While the limiters are basic on the dbx units I think they are enough to get by. I ran a Pa2 for probably close to 7 or 8 years and never burnt up any drivers. The venu360 is a big step up in functionality and sound quality but at that price there should be lots of good options out there. Personally I think if you are running your system into limit hard enough to think your limiter isn't up to the job the problem isn't your limiter, its that you don't have enough system for the job. I haven't needed to run my Skram's or my Danley's into limiting yet, if the day comes that it is required ill just start cutting up more wood 

2 hours ago, rolo95 said:

Hey Jay,

thanks for the reply

do you have any experience with Sanway ?

and.. AYyyyy https://reverb.com/item/19924547-xta-dpa-100-dual-amplifier-with-xta-processing

those are not in my league for now, what would be a decent limiter, i have an old Driverack PA, not the PA2, not the 260, people say that the Ashly digital have a nice limiter, but they are around 999,

i was looking maybe at a MINIDSP, no matter that you need a PC to tweak it, once is set is set it and forget it

Sorry no experience with the Sanway stuff but there is a lot of info out there regarding their offerings. Those prices on reverb are pretty crazy, real world pricing from a rep should be about 50-60% of those listed prices.

33 minutes ago, rolo95 said:

Thanks for sharing , that XTA pdf is pure gold!! never seen that detailed setup instructions for limiters, and btw, prices for drivers now are trough the roof, i wish have seen this thread in 2019

No problem, I agree that article really simplified things on my end. Following the recommendations within, I have a bunch of shows under the bridge at this point and between monitoring magnet temps or getting hands on drivers in my paraflex cabinets I feel confident my drivers are well protected and performing excellent at powers higher than I would have run them using many of the "rules of thumb" I had gathered in other resources. On that note, I am super happy with my XTA DPA100 amplifier. Its a bit spendy but considering the onboard dsp with 4 channels of dsp outputs for controlling of "slave amplifiers" I really think XTA hit a home run with these units. Great sound quality and easy to use software, lots of power onboard, highly recommended. I've done some smaller shows running my big Danley's plus 4 subs run entirely off the single Dpa100 on a single 15amp circuit with no problems. Nice and efficient power.

16 hours ago, rolo95 said:

I just found this thread and get hooked in to it! , i have a couple of questions tough, 

is it possible to modify a little to fit 2 12" drivers or 4 8"? , take my questions

with a grain of salt or 2 i dont have any sub design knowledge

budget 18" drivers like the 18TBX100 possible ?

does anybody  had tested the clones like Sanway, sinbosen and CVR 

https://www.ebay.com/itm/275253000470?epid=12031073806&hash=item40165b7916:g:MHcAAOSwrY5iS0mr

Best.

Rolo.

I cant speak for the 18tbx100 option but I have some thoughts on the amplifiers you listed. I have powered my Skrams using the CVR's, a Powersoft K10, an Admark k420 and Wasi w15k's. All of these amps work great and will give similar results. I would rate the CVR, K10 and Wasi so close in performance I doubt you could tell the difference between them in a blind test. Some people have stated that they think the Admark may have a slight advantage over the cvr on tone but I haven't experienced any evidence to support this, but I have only played around with their 4 channel models vs their 2 channel models. I don't think you can go wrong with any of those options.

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 

On 11/14/2021 at 4:30 AM, m_ms said:

Is a single Skram equatable to a box containing double, ported 18's? Moreover, is there a notable difference in bass presentation between the two? Please elaborate, if you care to.

/Mikael

Sound quality wise, I'd take skrams over double 18's all day every day.

18 hours ago, m_ms said:

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

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. 

Yes I have a pair of handles only on the hatch. Standing upright we can lift them 2 persons using the handles on the hatch as well I rounded the upper panel on the mount to serve as a carrying point on the front. I also have casters on the hatch side so the cabinet can be turned onto the wheels for easy rolling. I wouldn’t estimate the cabs are closer to 180 pounds but I haven’t weighed them to confirm. They can be stacked pretty easy with 4 people. 

2 hours ago, M88@FL450 said:

That’s great data man thank you! We’re you ever able to get a 2m GP Long Term test outdoors on these? 84v on a 4ohm 152 would be great! I think if I recall you got a 1m 1w sensitivity of 104 average some time ago. I’m doing some comparisons before I dive in the deep end of the Skram pool. 

 

That’s a great rig. Indoors at a bar like that it must be just off the charts! 

 

 

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 hours ago, M88@FL450 said:

That’s great data man thank you! We’re you ever able to get a 2m GP Long Term test outdoors on these? 84v on a 4ohm 152 would be great! I think if I recall you got a 1m 1w sensitivity of 104 average some time ago. I’m doing some comparisons before I dive in the deep end of the Skram pool. 

 

That’s a great rig. Indoors at a bar like that it must be just off the charts! 

 

 

I haven't man, sorry.  Hopefully someday the Skram will get the full testing treatment, I would think the Skhorn results should be a pretty good representation of what to expect obviously with lower output. The Skram also has larger vents so overall we would expect 2 skrams to outperform a single skhorn. At the end of the day it comes down to cabinet size. The Skrams 36x34x24 dimensions makes it a real compact 21" cabinet, I doubt any diy plan packs as much punch and deep extension in those dimensions. I can move these around on my own but they are at the very edge of what I would call manageable if its just you. If you have a dedicated crew that will help you move them into storage at 5am then perhaps look into larger cabinets

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. 

Mine don’t, but they have a newer dsp model that might 

Dave released an interesting video regarding bridge mono use. I gotta give it another watch or two to digest it more. This is something I’ve never come across, is anyone in here utilizing this technique? Seems to offer some nice benefits. 

https://youtu.be/HYbvA1DOR9A

40 minutes ago, peniku8 said:

That looks dope! Were you running them off the CVRs?

Yeah man, just a pair of 3002’s on the 6 Skrams on 15 amp plugs, the venue has shit for power. Still zero complaints, they work hard, stay cool and sound great. Think the k10 is getting lonely staying at home all the time, I’ve actually put it up for sale