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Ricci's Skhorn Subwoofer & Files

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Back in action + a bit of progress.

 

 

Hell yeah. At this rate you'll be putting power to it in a couple weeks.

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How the hell I missed this thread? Daaamn! I am working at some Bandpass subs and as you know they are the best option with good drivers now. I think I have simed more then 2000 iterations with all drivers possible from the worst to the best, to the impossible :))

Band-pass horn in Othorn dimensions on the market ALERT!

http://www.bassboss.com/subs/vs21-rum-punch-sub/

About 2 db less than the othorn though.

I would probably not try to have the smallest enclosure and go for larger cab, ports and horn to get most of the drivers and amp there because they cost much more  than wood and food for the people that carries it :)) probably 50*40*25 or something.

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That's

 

Band-pass horn in Othorn dimensions on the market ALERT!

http://www.bassboss.com/subs/vs21-rum-punch-sub/

About 2 db less than the othorn though.

I

 

Interesting. Yep that sure looks like what my half a Skhorn would have. Too bad they don't give you any real info on the vent tunings or the raw response shape. The one response shown is processed I'm sure. The response specs are quoted after dsp too.

 

Seems like a good time to be in pro audio. The cabs out now are way past what was available 5-10 years back. Looks like a full on arms race is going on. Prices are shooting way up accordingly as well. Pretty easy to spend $5K on one active cabinet these days. Of course it's not like one of these Skhorn cabs is cheap either. Figure a pair of 21sw152's, a SP-4000 plate amp, wood, duratex and hardware. That adds up pretty quick.

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Another brand that I know off of using this design principle (except KV2 ) is Traktion Sound , a small company with some interesting looking subs and speakers.

http://www.tractionsound.com/loudspeakers/bps221-harpia.php

They have a separated sub for 30-40 hz with dual 21", probably very efficient in the pass band and another for the rest of the range ,smaller with dual 18".that is probably a very good approach for best efficiency.

post-3306-0-83215800-1483055724_thumb.jpg

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Good points. What if you were building a 16cu ft cab for a single $500 18". How do 2 15's a few 12's or even a bunch of 10's or 8's compare in the same space? Things like that.

 

It's often easier to find the smaller drivers with specs that are closer to what is needed. They usually have a smaller voice coil so inductance can be lower and the smaller SD makes it easier to find drivers with a moderate to low Qts. Cheaper to replace if one blows and multiple smaller coils to share power often ups the long term thermal handling substantially. Way back when I was working on improving the GH I had a mocked up version using 6 Alpine 10's. Looked good really. Sad thing was the 6 SWR-10D2's were slightly cheaper than the single 18" LMS driver. Little bit heavy with 6 of them though and I found the issue with running drivers in series along the path length of a tapped horn. :unsure:

 

attachicon.gifGH 6x10 driver mount.png

 

People talk all kinds of crap about Bose but they have some of the best engineering talent around. it's just that their team is often given the task of making the most out of the absolute cheapest drivers that can be bought in order to maximize profits. They do a good job with it. I almost feel sorry for them not ever getting to use their skills on the transducers themselves. If they actually had a chance to use a $100 (At Bose cost) bass driver instead of ones that literally are probably <$5, they could probably do some impressive things.

 

The part some might skip over is investigating ways to slice & dice the cabinets into pieces with fractional performance. Obviously the image above would be easy to slice in 1/2, but what about 1/3rd or 1/4 or even less?  As you mention, sometimes drivers aren't so hard to find, and you increase the number of voice coils to split the power between.  Separating boxes also gets around the issues of spreading the loading point along the horn path, although I suspect 2 with some careful spacing might even be beneficial to resonances, but that would require some testing...

 

That gets to the other very useful reason to look at fractional designs.  Proof of concept.  If you have a design that looks very exciting, but you don't know how bends, real losses and Q's of resonances will be in reality, it can be very worthwhile and easier to test a 10-15" driver in a smaller package with the same acoustic design.  The ultimate test is if a pack of the smaller subs is comparable to a single large sub, which it theoretically should be.

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While I think scaled down systems are theoretically interesting, the construction costs don't scale so nicely.  Multiple closed cabinets also offer lower percent usable volume.  Where smaller cabinets get interesting is when placed in multiple locations, either to achieve smoother response in small rooms or to improve audience coverage and/or reduce unwanted sound radiation toward the stage or toward neighbors.  The use of multiple amplifier channels and optimized DSP allows for even more options, but of course raises costs even further.

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Another brand that I know off of using this design principle (except KV2 ) is Traktion Sound , a small company with some interesting looking subs and speakers.

http://www.tractionsound.com/loudspeakers/bps221-harpia.php

They have a separated sub for 30-40 hz with dual 21", probably very efficient in the pass band and another for the rest of the range ,smaller with dual 18".that is probably a very good approach for best efficiency.

 

Where do you keep finding this stuff!? LOL. That's another company I've never heard of.

 

BTW it seems like Bassboss might be the old Bassmaxx renamed? I had heard of them.

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I have good internet connection :)) best in Europe for sure (1Gbps connection for 10$ a month via fiber optics ;))

Yes, Bassboss is BassMaxx renamed because that was a trademark so he couldn't use the name anymore. His approach for using BR for 22-60 hz and Horns for 40-100 with an excellent integration is very similar to a bandpass horn approach.

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That's great man. Can't wait to hear what you think of it. I've never even heard one yet.

 

I'll try and get you some suggested filter settings today. It was just a high pass at like 25 and a single band eq notch for that peak above 150. I'm not sure how large that will be since HR tends to exaggerate peaks a bit plus the low pass should knock that well down too.

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That's great man. Can't wait to hear what you think of it. I've never even heard one yet.

 

I'll try and get you some suggested filter settings today. It was just a high pass at like 25 and a single band eq notch for that peak above 150.

 

Great, planning on firing it up this afternoon!

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Hey dsl1,

Here's a rough stab at suggested signal processing. This is based on the model only and could probably be improved with actual measurements. Do you have any way to measure the response?

 

Anyway.

 

EQ 194Hz , q 5.0, -7dB

Low pass filter, 3rd order or steeper. 60-120Hz depending on taste / system.

High pass, 3rd order Butterworth 24Hz with all ports open, 3rd order Butterworth 20Hz with 4 ports open.

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Hey dsl1,

Here's a rough stab at suggested signal processing. This is based on the model only and could probably be improved with actual measurements. Do you have any way to measure the response?

 

Anyway.

 

EQ 194Hz , q 5.0, -7dB

Low pass filter, 3rd order or steeper. 60-120Hz depending on taste / system.

High pass, 3rd order Butterworth 24Hz with all ports open, 3rd order Butterworth 20Hz with 4 ports open.

 

Yes have a UMM-6 calibrated mic. Let me know what you'd like to see. 

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What would that weigh?

 

Using a quick estimate of baltic birch weight found online without drivers it weighs ~180# - that is likely off but in in the ball park?

 

Then the B&C SW152-4's are ~40# each.

 

So looking at ~260# fully loaded?

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That should be about right. SW's estimates about 180 for the empty cab. Another 10-15 lbs if all hardware is used. Add another 5-10 lbs or so if a plate amp is used. Looks like one using all the handles, pole mounts, hardware, duratex'd, plate amp with the dual Ipal's should come in right at or just under 300 I'd guess.

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That should be about right. SW's estimates about 180 for the empty cab. Another 10-15 lbs if all hardware is used. Add another 5-10 lbs or so if a plate amp is used. Looks like one using all the handles, pole mounts, hardware, duratex'd, plate amp with the dual Ipal's should come in right at or just under 300 I'd guess.

 

+5# of PL mess that somehow got everywhere. 

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Wanted to ask is the DXF file that Ricci has made the file you are using with your CNC?

 

I was going to ask a local place how much it would cost to CNC a single cabinet for me if I provide the plywood. Just want to make sure I know what I am getting if they do the job though. If it is exactly what you made then I need to buy handles to complete the build.

 

I forgot I have Draft Sight on my computer. SO I looked at the file. Is it hard to change the file to fit on  4 x 8 sheets instead of 5 x 5?

 

I cant afford the expensive plywood so I will be going with the cheapest I can find in 4 x 8ft sheets. 

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Wanted to ask is the DXF file that Ricci has made the file you are using with your CNC?

 

I was going to ask a local place how much it would cost to CNC a single cabinet for me if I provide the plywood. Just want to make sure I know what I am getting if they do the job though. If it is exactly what you made then I need to buy handles to complete the build.

 

I forgot I have Draft Sight on my computer. SO I looked at the file. Is it hard to change the file to fit on  4 x 8 sheets instead of 5 x 5?

 

I cant afford the expensive plywood so I will be going with the cheapest I can find in 4 x 8ft sheets. 

 

No, I made my own model -> new dxf files. Any CNC shop is likely going to have to make tweaks based on their setup (machine, bit sizes, bits available) and material thickness's you have locally. For example, the 18mm baltic birch we have here is all about 17.9mm thick but the 12mm is 12.1mm. If I made my 12mm dados just a bit over 12mm, they would not fit. Ricci's dxfs also do not include dados. 

 

If keeping costs down is a priority I would suggest not going the CNC route unless you're making a bunch of them to justify the extra setup expense. If you've built an Othorn / Ghorn or equivalent horn you'll be fine. The SKHorn is easier than those in my opinion.

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I'd agree that the Skhorn type of cab is easier than an Othorn or GH. The simple plan is attached. Adjust bracing, hardware, drivers, hatches, cab width to taste. That's really all you need to be important with is what's in the attachment. The rest can be adjusted to your material or tools, etc. That's really all there is to it. Get the port panels and the short slot horn path/driver baffles correct and built out from there. Even those are more tolerant to inaccuracies than with a TH or FLH. Most of it is figuring out how to get the drivers in and out and brace the damn thing.

 

post-5-0-47519500-1484146443_thumb.jpg

 

 

I did the original Othorn and GH files with cnc in mind but more people seemed to build them with regular tools so the dimensions on the cnc print all had to be adjusted and I ended up with 2 prints and sets of assembly files. Also each cnc shop will likely have to make tweaks and adjustments anyway due to their particular setup and tooling so it just makes more sense to do a single print that can be built by the regular Joe's with table or track saws and let the cnc shops make their own adjustments needed. They would usually have to anyway.

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