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Ricci's Skhorn Subwoofer


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#21 Ricci

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Posted 08 December 2016 - 05:24 PM

I'll be using my 21Ipal's for mine whenever I get around to it.

 

 The design above is made for huge or outdoor spaces and very loud playback like the Othorn. Pro audio type stuff. Houses or HT weren't part of the consideration during the design. What I'm thinking is a different design with deeper extension using more affordable drivers that others can build without too much investment. Something not as brutal and more geared towards home or HT duty.



#22 Samps

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Posted 08 December 2016 - 06:01 PM

Sounds like you're stuck with Dayton. They're likely the only company that you can count on to have the same driver available for years to come. You could use an SI or Sundown but the driver might be discontinued a year from now. Alpine would work if you can shrink to 15s, or 4 12s. 4 sws 12s would be cheap and have a lot of stroke. And the options of dual coils would give any ohm load you needed. FS is high though.

#23 SME

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Posted 09 December 2016 - 08:36 AM

There just aren't a lot of low Qes drivers that also happen to be low inductance and cheap.

 

Wonder why???  I've been looking for years, they just aren't out there.

 

.

 

Spent the past day trying to come up with alternate drivers with such features. I really...can't think of any. Hate to say it but you might have to look into high-end car audio but then things are expensive again.

 

The past half-decade has been full of low cost, large-ish displacement (for the money) drivers and they are almost always higher Qes or something else making them otherwise unsuitable for such alignments.

.

Frustrating.

 

I suspect it comes down to physics, cost, and marketability.  I suspect most high excursion drivers are targeted toward sealed applications where low Qes is typically less favored.  In a ported system, there's often plenty of room on the baffle to add another driver if Xmax is an issue, and this typically brings efficiency advantages over relying on a single higher Xmax driver.  Of course, these hybrid 6th order BP systems have their own unique requirements.

 

What frustrates me is the physics of reproducing < 20 Hz bass from very small cabinets.  As interested as I am in under 10 Hz content, I am seeing anecdotal evidence suggesting that those frequencies are better left to Crowsons.  So why not build ported/horn/hybrid cabinets for my 4 UH-21s?  Because, they'd have to be huge to tune low enough (say 12-13 Hz) and provide a worthwhile output advantage over the sealed.  For the space I have to work with and my desire for strong 10-20 Hz output, sealed wins period.  And oddly enough, super motored drivers like the IPAL 21, UH-21 and RF TS-19 that are well suited to a Skhorn or other high output alignments also appear to be ideal for low frequency performance in very small sealed boxes like I'm building.

 

It's just that building sealed subs doesn't feel all that adventurous.  I reckon some day when I have the space or I decide I want something I can haul to large spaces or outdoors, I'll have to put these UH-21s in cabinets that allow them to show their real stuff.


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#24 SME

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Posted 09 December 2016 - 08:44 AM

Also. After SME's post about the back panel I might make some changes there. Probably just change the pack panel to but up against the ends of the side panels rather than in between them. That would help. Need to look at it.

I think you mean Samps here.



#25 Ricci

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Posted 09 December 2016 - 07:37 PM

I think you mean Samps here.

 

 Whoops...Fixed.

 

 

It's just that building sealed subs doesn't feel all that adventurous.  I reckon some day when I have the space or I decide I want something I can haul to large spaces or outdoors, I'll have to put these UH-21s in cabinets that allow them to show their real stuff.

 

That's where I'm at. I guess it's boredom or being burnt out or whatever but building a sealed or even big vented system doesn't excite me like it used to, even if they make a whole lot of sense in most cases. That's why I mostly work on weird cabs for huge spaces anymore. It's more fun for me (and frustrating).



#26 MemX

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Posted 09 December 2016 - 10:50 PM

Just one of the joys of being human - the constant quest for new and exciting things that teach us and stretch our brains :)

 

 

 

(Well, most of us - there are a depressing number of morons out there with no desire but to do as little as possible with their life...)


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#27 Infrasonic

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Posted 09 December 2016 - 10:52 PM

It is more fun.

 

 

I like to throw in that while sealed gets it done, it's just so inefficient in the process (producing <Fs content). I mean, c'mon... to even sorta achieve what I want to achieve I have FOURTEEN 18's in a small room and it's still.... not enough.


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#28 maxmercy

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Posted 09 December 2016 - 11:41 PM

NOT ENOUGH?!?!?  In what way?  ULF Tactile response, midbass slam (I can actually believe that one in a small room), or just can't reach Ref? 

 

WTF will be enough, 'fear for your structure'  SPL?  'Fear for your life' SPL?  Nearfield pistol/rifle/shotgun/artillery blasts triggered by a threshold on the soundtrack?

 

Having been 100 meters away from a 155mm Howitzer I didn't know was going to send some hurt downrange (without hearing protection), I can tell you that 'fear for your f'ing life' SPL starts at around 140dB if it is not anticipated.  Do you really need that, and the innumerable 'what, can you repeat thats' you will ask servers in crowded restaurants for the rest of your life? 

 

C'mon man.....

 

 

JSS


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#29 lukeamdman

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Posted 10 December 2016 - 03:52 AM

It is more fun.

 

 

I like to throw in that while sealed gets it done, it's just so inefficient in the process (producing <Fs content). I mean, c'mon... to even sorta achieve what I want to achieve I have FOURTEEN 18's in a small room and it's still.... not enough.

 

 

NOT ENOUGH?!?!?  In what way?  ULF Tactile response, midbass slam (I can actually believe that one in a small room), or just can't reach Ref? 

 

WTF will be enough, 'fear for your structure'  SPL?  'Fear for your life' SPL?  Nearfield pistol/rifle/shotgun/artillery blasts triggered by a threshold on the soundtrack?

 

Having been 100 meters away from a 155mm Howitzer I didn't know was going to send some hurt downrange (without hearing protection), I can tell you that 'fear for your f'ing life' SPL starts at around 140dB if it is not anticipated.  Do you really need that, and the innumerable 'what, can you repeat thats' you will ask servers in crowded restaurants for the rest of your life? 

 

C'mon man.....

 

 

JSS

 

I remember when a Bose Acoustimass module with two 5.25" drivers put a big grin on my face.  Later I thought a 12" Velodyne was just insane...then a 15"...then a 18"...then two 18s...etc...etc...etc. 

 

When I have GTGs and I see people's first exposure to 130db and now 140db I remember reacting that way but it doesn't last. 

 

I mean seriously, on the boards now days there's nothing special about a 8x18" system.  Crazy. 



#30 SME

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Posted 10 December 2016 - 06:42 AM

NOT ENOUGH?!?!?  In what way?  ULF Tactile response, midbass slam (I can actually believe that one in a small room), or just can't reach Ref? 

 

WTF will be enough, 'fear for your structure'  SPL?  'Fear for your life' SPL?  Nearfield pistol/rifle/shotgun/artillery blasts triggered by a threshold on the soundtrack?

 

Having been 100 meters away from a 155mm Howitzer I didn't know was going to send some hurt downrange (without hearing protection), I can tell you that 'fear for your f'ing life' SPL starts at around 140dB if it is not anticipated.  Do you really need that, and the innumerable 'what, can you repeat thats' you will ask servers in crowded restaurants for the rest of your life? 

 

C'mon man.....

 

Maybe he just needs a Crowson transducer surgically implanted into his diaphragm, although his answer will be interesting.

 

Due to the wide bandwidth and high sensitivity of the drivers I'm using for the subs and MBMs I'm building, I'll probably have > ~140 dB capability between 60-200 Hz or so, and I'll have > 130 dB capability from 20-1000 Hz probably.  I *might* be able to reproduce that Howitzer cannon, but I guess it depends on its spectrum.  That kind of capability scares me, like what happens if I have an equipment malfunction?  My DSP runs on a computer and is essentially running at 100% volume all the time.  What if I encounter a software bug, or a neutrino flips the wrong bit in memory and causes it to output white noise to all channels?

 

I remember when a Bose Acoustimass module with two 5.25" drivers put a big grin on my face.  Later I thought a 12" Velodyne was just insane...then a 15"...then a 18"...then two 18s...etc...etc...etc.

 

Wow, does Bose offer its Acousticmass modules with bigger drivers?  I have a hard time believing a pair of 5.25" drivers can do much of anything.

 

My first audio system other than a tape recorder was hand-me-down from my mom of an old Marantz stereo receiver and a pair of Bose Interaudio 4000, ported with 10" woofers.  The bass they offered, while a bit one-noteish, was very satisfying compared to most other speakers I'd heard and even some subs.  The weak point was the 3" paper cone mid/tweeter, which seemed to overload and distort badly before the woofers ever complained.  I remember thinking "The Matrix" sounded really cool on them, and I lived with and enjoyed them for over 15 years in all.  :)  I never thought of them as being that great (and they weren't), but they still sounded better than the vast majority of stuff in other peoples' homes.



#31 maxmercy

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Posted 10 December 2016 - 11:52 AM

I am just joking around with Infrasonic, as he probably was above....Hence the "C'mon man" comment.  I am hoping his response will make me laugh, as he can pull very appropriate memes and other interweb hilarity at will.

 

JSS



#32 Ricci

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Posted 10 December 2016 - 01:29 PM

I *might* be able to reproduce that Howitzer cannon, but I guess it depends on its spectrum. That kind of capability scares me, like what happens if I have an equipment malfunction? My DSP runs on a computer and is essentially running at 100% volume all the time. What if I encounter a software bug, or a neutrino flips the wrong bit in memory and causes it to output white noise to all channels?


That is one of my nightmare scenarios. That and overall reliability are what keeps me from using a pc.

Bose uses an 8th order or 6th on some of their modules and none of them go low at all so they do leverage quite a bit out of the weak sauce drivers.
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#33 lilmike

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Posted 12 December 2016 - 05:50 AM

...That kind of capability scares me, like what happens if I have an equipment malfunction?  My DSP runs on a computer and is essentially running at 100% volume all the time.  What if I encounter a software bug, or a neutrino flips the wrong bit in memory and causes it to output white noise to all channels?

 

....

 

 

That is one of my nightmare scenarios. That and overall reliability are what keeps me from using a pc.

...

 

 

This. Times eleventy bazillion.

 

I had an early home theater PC go nuts on me. Was not a pleasant noise. The sub made some awful noises, then some smoke. Killed the driver and the plate amp. My main speakers survived, but that was before I had any sort of real power on tap.

 

I'll run hardware DSP, not going to take that chance with software.



#34 lilmike

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Posted 12 December 2016 - 05:51 AM

It is more fun.

 

 

I like to throw in that while sealed gets it done, it's just so inefficient in the process (producing <Fs content). I mean, c'mon... to even sorta achieve what I want to achieve I have FOURTEEN 18's in a small room and it's still.... not enough.

 

My pair of 12s and I will just sit over here at the kids table...



#35 Ricci

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Posted 12 December 2016 - 02:58 PM

Looks like the Alpine S-15 might just work in one of these style of cabs after all.



#36 lilmike

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Posted 12 December 2016 - 08:35 PM

Really...  That was one of the first ones I tried, I must have screwed something up somewhere along the way.



#37 Ricci

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Posted 12 December 2016 - 09:17 PM

Attached quick sim doesn't look too bad. Tuning a bit higher with the vent and increasing area would help overall sensitivity & output some. Looks like a 500-750w amp would get it to rated xmax or a bit past. About 325L total. Rough guess is that would be a cab roughly 24x30x30. Big but not out of the ordinary for vented and way smaller than a horn that reaches as low. Could probably shrink it some and tune a little higher.

 

 

6thBPH SWS15d4 stab.png

6thBPH SWS15d4 stab vs vented.png

 

 



#38 SME

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Posted 13 December 2016 - 06:35 AM

This. Times eleventy bazillion.

 

I had an early home theater PC go nuts on me. Was not a pleasant noise. The sub made some awful noises, then some smoke. Killed the driver and the plate amp. My main speakers survived, but that was before I had any sort of real power on tap.

 

I'll run hardware DSP, not going to take that chance with software.

 

Bummer.  Were you not able to shut it down or pull the plug quickly enough?

 

FWIW, I don't distinguish that much between so-called hardware and software DSP because a hardware solution will almost always run some kind of internal software (i.e. firmware or microcode) anyway.  Both are potentially vulnerable to bit flips and bugs.  The big difference with a PC solution is that a lot more software gets involved (i.e., the operating system, hardware drivers, and even other programs that are running), so there's a lot more places where bugs can be present.  On the flip side, the memory protection provided by a modern operating system will often cause a bad program to crash quickly instead of misbehaving perpetually as a hardware unit with simple firmware might.



#39 lilmike

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Posted 13 December 2016 - 05:30 PM

The whole system was in a closet at the back of the room. I got there quickly, but wasn't able to save the sub and amp. Not that great a loss, but still. I still worry about my Media PCs flaking out on me,  but I still rely on them. I just don't use them to do the DSP stuff too. Heck, any more, my AVR can handle nearly all I need. I kicked around UltimateEQ for a while, decided against that for now. Have had no luck at all with JRiver. For now, DSP is in the iNuke, or in the MiniDSP. Have some FreeDSP kits to play with one of these days too.

 

I hear you wrt the code internally. Less code means less to go wrong. The typical DSP runs a dedicated code set that is hopefully designed to fail gracefully. A typical HTPC? Who knows? I've run lots of different flavors, some have been robust, some are absolute disasters. I think it was MediaPortal on Windows XP that baked the sub, but that was a long time ago. For frontends now, I'm typically running some flavor of Kodi on Linux, but I am still churning through things to find the right combination of what I am after.



#40 SME

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Posted 14 December 2016 - 09:54 AM

Yeah.  My DSP PC runs Linux and is dedicated to the task, so there's otherwise just system stuff running on it.

 

I wouldn't assume hardware DSPs are designed to "fail gracefully" though.  I learned the hard way that the MiniDSP OpenDRC-AN is very sensitive to static electricity, even on the outside of the box.  Once zapped, the thing stopped outputting most sound except for occasional loud pops.  I also observed the units behaving in similar fashion every so often after being power cycled.






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