Ricci

21sw152-4 should be a very good match. 8ohm a little less smooth but should be fine. If you give me a couple days I should have the prints up. I swear!

Well I added some info and screenshots at least. I don't have real cabs or test data yet but it will happen this summer. Based on the results from my last couple of designs I've got a high confidence of what these are going to behave like.

The 21NLW9601 models really well in this cab. Looking forward to your thoughts on the cab and the 3 drivers.

You need a bit of clearance when putting on the final side panel. If those were cut at exactly the wood thickness you would never be able to get the final side to seat correctly.

Sorry guys I meant to make this topic hidden. Kinda jumped the gun a bit. Thought I would have the files ready but Ice been too busy to wrap them up the last couple of days. Hoping to get to it before the week is out.

This is the long delayed single driver sub similar in design to the Skhorn. Overall the performance goals and criteria were quite similar. Big surprise there! The Skhorn works so well at what it does that I didn't feel the need to reinvent the sub for this one. This is primarily designed as a professional sound reinforcement or live sound style subwoofer. Big output and clean sound in very big spaces, while covering the typical bass heavy range of music, has always been the primary mission for this sub. Same as it was with the Othorn and Skhorn. It can and I'm sure WILL be employed for other types of situations, but it's a festival or club sub that just happens to be flexible and neutral enough to work in a variety of scenarios. The main differences between the Skram and the Skhorn are as follows. Optimize it more for the cost effective 21's like the 21DS115 and Lavoce SAN214.50 rather than the Ipal drivers like the Skhorn. The Ipal's still work of course, but I relaxed things a bit for the drivers that are a little easier to afford and power. Increased size: Originally I wanted to basically saw the Skhorn in half and slap a top panel on there with modded bracing. It would be a very compact 21" sub, which is great, but the driver would fire directly into an outer panel and even with bracing this is a lot of energy being beamed on axis into a large outside panel. I've never been a fan of high pressure loadings with big drivers that do this. I always want the direct on axis energy from the cone to act on internal panels that are going to keep this energy inside of the cabinet better. This required a rearrangement of the internals. I also added a bit of size while I was at it. I decided to stop at a size that was significantly smaller than the full Skhorn, but not as small as a true half. If this cab is too big or heavy you could always build the true half Skhorn, which would be 24x32x27.71. Increased vent area and slightly increased vented chamber volume. This should help the noise, compression and output near the vent tuning. Increased vent area and length means that the vent pipe resonance is lower in frequency than the Skhorn. I'm, expecting that the response will be less smooth above 150Hz, but that's the tradeoff made for bigger vents. The Skram has 4 vents instead of 3 like on the Skhorn. I decided to add one more for even more tuning options. Tuning with all vents open is basically the same. Being a single driver design, the Skram does not have the dual opposed drivers for mass induced vibration control like in the Skhorn. Other than these changes I would expect that this design behaves and sounds very similar to the Skhorn. I'd expect that the two could be used together without issue. They are more alike than dissimilar. Skram Dimensions: 24"x32"x36" (609.6mm x 812.8mm x 914.4mm) Weight: Cab=115lbs or 52kg projected (Driver will add another 25 to 55lbs (11 to 25kg) depending on the driver. Vent Tuning: All vents open = 29.5Hz / 3 vents open = 25.5Hz / 2 vents open = 20.5Hz / 1 vent open = 14.5Hz Each vent is greater in area than a 6" pipe. All vents open is equivalent in area to 4x 6" ports. All of the usual pro 21's should be a good match. 18Sound 21ID, 21NLW9601 B&C 21DS115, 21SW152, 21Ipal RCF LF21N551 looks decent Lavoce SAN214.50 Eminence NSW6021-6. NOTE about the prints! These are extremely detailed due to being designed in Solidworks and the plans from which my personal cabs would be built. The simplified layout drawing is really all that should be adhered to to build this sub. The bracing and hatch can be simplified to suite your own ideas or the tools available to build the cabs. Just make sure it is solid! Any or all of the hardware can be deleted or substituted or modified to suite your needs. Even outer dimensions can be adjusted within reason. Think of the plans as a chassis guideline that can be modified to taste. You don't have to put all of those holes in your braces or use the handles, a half inch roundover on the cab edges, add a cutout for a plate amp on the hatch, etc... Skram print.pdf skramcutlist12mm.pdf Skramcutlist18mm.pdf DXF files... Back Brace 1^Skram_TI x2.DXF Back Brace 2 ^Skram_TI x 2.DXF Bottom Braces^Skram_TI.DXF Bottom Brace^Skram_TI x 2.DXF Front Brace^Skram_TI x 2.DXF Mid Brace x 4^Skram_TI.DXF Top Brace^Skram_TI.DXF A^Skram_TI.DXF Back^Skram_TI.DXF Bottom^Skram_TI.DXF B^Skram_TI.DXF C^Skram_TI.DXF D^Skram_TI.DXF E^Skram_TI.DXF Front^Skram_TI.DXF Hatch Brace Small^SKHorn.DXF Hatch Brace^SKHorn.DXF Hatch^SKHorn.DXF MirrorSide^Skram_TI.DXF Double - Middle Two.SLDPRT Double - Middle Two.SLDPRT.DXF dxf_filelist.txt Single - Left or Right.DXF Triple.DXF Back^Skram_TI.DXF Bottom^Skram_TI.DXF E^Skram_TI.DXF Side^Skram_TI.DXF Top^Skram_TI.DXF Side_1^Skram_TI.DXF Top^Skram_TI.DXF

Solidworks or E-Drawings Pro.

I see I missed this question. How many TH-18's does DSL recommend? That'd be a good place to start. I'd think 2 per side would be a good start. 4 per side would be a whole lot more fun though.

I don't know what the problem is. I just opened every file linked above without issue. Perhaps try to contact someone who has already downloaded and built from the plans. Maybe their file will work for you.

I hear that Mike...Way more ambition than time eh? I know that story. I second the caution to watch the SC input level. It's easy to smoke one with an amp. I'm using an old Crest 8002 with a blown channel that it isn't worth it to fix. Does just fine with the 1 good channel sitting on a test bench though.

Sine sweep SPL value is not a peak figure. None of the ones shown here are peak. Crest factor is 3dB.

Hmm. Man I think its splitting hairs. Should be fine. Your talking a couple hertz tuning difference if that. The vented chamber is relatively forgiving of small changes. Id say roll with it.

Simple mod...how much longer did you make them?

Ouch blown amp stages...I've had similar happen with unbridged smps amps. This is partly why I avoid running them like this for heavy duty bass now. It seems to shorten the life span quite a bit and induce more failures. Most of the pro amps I've used seem to be fine on bass duty, half bridged until down around 25 to 30Hz with normal duty cycle music. Lower impedance loads / higher current requirements/ higher sustained power and especially very deep bass frequencies below 25Hz start to cause issues. With usual music primarily above 30Hz you may never notice. I go straight to bridged for subs anymore to avoid the possibility under demanding circumstances. YMMV.

I did some quick modeling and it looks like the tuning would come in at about 31.5 or 32Hz from the original 28 or 29Hz tune. A little more than I had guessed, but the response doesn't change much. It looks good. I'd say this modification would be barely noticeable if both were side by side and you have a little extra vent area. Go for it.

If the extra 60mm is added to the vents only it would raise the tuning a bit. I'm not sure how much exactly but I don't think it would be more than a couple of hertz at most. Probably not a big deal. I would mainly use the rms limiter and leave the xmax and voltage limiter set out much further. The drivers mentioned here typically will not actually damage themselves mechanically without severe abuse and they audibly let you know first. Also with the standard tuning and a high pass below 25Hz it will take a ton of voltage to induce over excursion. Peak voltages I'd likewise leave set way out. The cab will take it for short term peaks. The main concern is long term heating up of the coils so the rms limiter should be the biggest focus. The Linea's look good but I don't have any experience with them yet. Seems like they are getting popular. Looks like that would be a good choice to run 4 Skhorns (or more) per amp. With 4 ohm drivers you can wire 2 channels bridged for a rated 10Kw into a pair of Skhorns.

I would recommend using an amplifier for large high power woofers. However you don't need to run it as hard as you might think. 1 to 3 volts is plenty. The main thing is load invariance, linear response and freedom from clipping. If you cannot get an amp try to use a good quality headphone output these usually have a better result driving low impedance loads and a bit more current capability than a line level output. Things like the DATS can work in a pinch but the drive level is only a few milli-volts. It's not enough for accurate repeatable measurements on the types of drivers I usually test. IMHO.

All speakers have inherent differences in power handling vs frequency. Its assumed that any serious outfit would work out limiting or amplifier matching depending on content/ use, amps and drivers for their individual case. It depends quite a bit on all of these factors. I can say that with my pair I've beat on them hard and haven't had any issues but I'm not banging off the clip / limiter for 12hrs with extremely compressed content either. YMMV. If you have the ability to do true long term power averaging I'd set it to somewhere between 500-1500w depending on drivers to be truly safe but that is a absolutely huge amount of average power with typical music crest factor. Way more than it seems. If you are matching the amp rating to the recommended driver AES power rating range and not exeeding it or running consistently into the limiter it shouldn't be a concern. Running a 9kw rated k20 channel for all it is capable of into a single 21ipal loaded Skhorn with a driver power rating half that wouldn't be recommended. Some common sense is needed. Running about 2 to 5kw of amp per cab depending on the drivers used and application is about right. The amps would be clipping or limiting the peaks well before the average power is reached with normal music.

18sound should work also, either the 21id or 21nlw9601. RCF lf21n551 Looks workable. Whichever of these 21's is most cost effective should work well for you. I've never had any trouble with burning up drivers in the Skhorn. Don't think anyone else has. Its got 2 drivers with the highest power handling ratings on the market and a decent air volume and air exchange rate. This was also part of my goals with the design. It will take quite a bit to overheat a pair of 1800w AES rated drivers. Unless you are talking about running a whole bridged amp on each one I wouldn't worry about it.

We will know that this summer.

Hey Revolt, As far as I know no one has run more than 2 cabs yet. This is a significantly more powerful design in a semi compact size than any others I'm aware of on the market. Especially in the 25-40Hz range. 6 or 8 should be devastating. The only things that are likely to compete or exceed these on a 1 vs 1 basis are Danleys largest most expensive subs like the BC415, TH812, or DBH218LF and other major companies top of the line largest, most expensive subs. M-force based systems, etc...As far as subs go you can accomplish a lot with cabinet design and " magic" ,but at the end of the day you need power handling, cone area and the ability for the drivers to move a lot of air via high xmax. Dual top of the line 21's are used for a reason. The Faital 18's give up displacement capability, cone area and I've not simulated them or tried them in this cab. Out of what Faital offers the 18XL2000 is probably the best match without giving up too much output. I'd really recommend 21's though. The extra cone area helps out a lot. If cost is an issue the Lavoce SAN214.50 models very well. I'm not sure what it would cost in the UK but here it is very reasonably cost ($450 usd). I have 2 on hand for testing and so far it looks like a lot of driver for the money.

Yes...Different ports. I'll post more about it when I get closer to being finalized.