Official JTR Orbit Shifter Subwoofer Thread - Page 34 - AVS Forum
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post #991 of 1199 Old 09-29-2013, 06:43 PM
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Quote:
Originally Posted by lbrown105 View Post

that link is not working for me. what does it say?
Well that's weird. Here try this out:

http://billfitzmaurice.info/forum/viewtopic.php?f=10&t=1130
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post #992 of 1199 Old 09-29-2013, 08:50 PM
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Quote:
Originally Posted by DotJun View Post

Well that's weird. Here try this out:

http://billfitzmaurice.info/forum/viewtopic.php?f=10&t=1130

That is not all thrue. In the TH or FLH design is important to have not to high compression ratio for 18, 21 or 24 inch drivers. Hornresp program formula = driver diaphragm piston area (sq cm) Sd/S2 compression ratio = smile.gif
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post #993 of 1199 Old 09-29-2013, 09:56 PM
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Quote:
Originally Posted by DotJun View Post

Well that's weird. Here try this out:

http://billfitzmaurice.info/forum/viewtopic.php?f=10&t=1130
now its working. I have never built a horn sub so all I can say is my OS's sound fantastic. Maybe it takes a really good horn builder to use the 18in driver in a horn. Maybe Jeff is going beyond conventional wisdom I don't know but the statement never use an 18 in a horn sub doesn't seem clear to me since the OS is considered by most, one of the best subs out there.

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post #994 of 1199 Old 09-29-2013, 09:58 PM
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Here is a quote, "As for eighteens, forget about it. Aside from the fact that they are very vulnerable to damage with high power inputs, they just don't work well in horns. Horn loaded cabinets get low extension via a long path length; an eighteen takes up so much room inside the cabinet that there's not enough room left over for a long horn. Eighteens are only used by those who don't understand how horns work, or those selling their horns to those who don't understand how horns work."

Too bad Jeff isn't on the forums to reply to this!
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post #995 of 1199 Old 09-29-2013, 10:31 PM
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Quote:
Originally Posted by jlpowell84 View Post

Here is a quote, "As for eighteens, forget about it. Aside from the fact that they are very vulnerable to damage with high power inputs, they just don't work well in horns. Horn loaded cabinets get low extension via a long path length; an eighteen takes up so much room inside the cabinet that there's not enough room left over for a long horn. Eighteens are only used by those who don't understand how horns work, or those selling their horns to those who don't understand how horns work."

Too bad Jeff isn't on the forums to reply to this!

Yeah, also try telling that to Josh Ricci who also designed the Gjallardhorn sub.
http://www.data-bass.com/data?page=system&id=45&mset=42

Which has crazy output too. wink.gif

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post #996 of 1199 Old 09-29-2013, 11:14 PM
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Originally Posted by jbrown15 View Post

Yeah, also try telling that to Josh Ricci who also designed the Gjallardhorn sub.
http://www.data-bass.com/data?page=system&id=45&mset=42

Which has crazy output too. wink.gif

Or Othorn with B&C 21sw152-4 driver smile.gif and DSL TH 221
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post #997 of 1199 Old 09-29-2013, 11:47 PM
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Quote:
Originally Posted by jlpowell84 View Post

Here is a quote, "As for eighteens, forget about it. Aside from the fact that they are very vulnerable to damage with high power inputs, they just don't work well in horns. Horn loaded cabinets get low extension via a long path length; an eighteen takes up so much room inside the cabinet that there's not enough room left over for a long horn. Eighteens are only used by those who don't understand how horns work, or those selling their horns to those who don't understand how horns work."

Too bad Jeff isn't on the forums to reply to this!

He probably don't need too. He's speakers and subs speak for themselves smile.gif. And almost everyone on this forum knows JTR's are solid built with output and quality sounding. Wow, I said that with confidence even though I havn't even heard any of the JTR line up. Well, I will soon..biggrin.gif
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post #998 of 1199 Old 09-30-2013, 12:01 AM
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Btw, how long has the OS been out? After reading through this thread when I was thinking of going with dual OS. I never came across reading about a failed OS. And don't forget about all those GTG's when those bass heads took the OS to insane levels and still not one driver failure..
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post #999 of 1199 Old 09-30-2013, 12:25 AM
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Quote:
Originally Posted by rhed View Post

Btw, how long has the OS been out? After reading through this thread when I was thinking of going with dual OS. I never came across reading about a failed OS. And don't forget about all those GTG's when those bass heads took the OS to insane levels and still not one driver failure..


OS LF since may, 2010 smile.gif

OS LFU since january, 2012 smile.gifsmile.gif
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post #1000 of 1199 Old 09-30-2013, 12:53 AM
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Yea that's why I'm confused after reading that post because my os seems to function far greater than I could ever push it to.

The things said in that post that sticks out to me are: 1) large drivers don't work good in horns. My os has an 18 and at least I think they work good. 2) large drivers are vulnerable to high power in a horn. Since when has 4k watts been anything but high power? Though maybe this part does not fall in that category since I think Jeff uses limiters?
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post #1001 of 1199 Old 09-30-2013, 01:18 AM
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Quote:
Originally Posted by rhed View Post

Btw, how long has the OS been out? After reading through this thread when I was thinking of going with dual OS. I never came across reading about a failed OS. And don't forget about all those GTG's when those bass heads took the OS to insane levels and still not one driver failure..

Especially those drivers that are used in the countless venues that go on for extended periods of time. They don't dig deep like for HT use, but they are belting out high SPL's.

Im not sure if they are the exact same driver in the pro models, but im sure they are produced by the same quality manufacture.
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post #1002 of 1199 Old 09-30-2013, 07:20 AM
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Originally Posted by DotJun View Post

So I was on the bfm forum cause I was thinking of picking up plans for the auto tuba when I ran into this article Bill wrote: 18" woofer in a horn

So what's up with that? Someone clue me in because the OS is both a large cone and high amounts of amplification and so is the gjalaborn as far as I know.

That was posted in 2006, maybe horn design has changed? Drivers improved? Too large for venues at the time? I am sure there are reasons but that 18 with damage did not work for a horn, not all 18's and back then what was available? I know there were many 18 inch horns for pro audio but never for low frequencies.
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post #1003 of 1199 Old 09-30-2013, 07:53 AM
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Originally Posted by MKtheater View Post

That was posted in 2006, maybe horn design has changed? Drivers improved? Too large for venues at the time? I am sure there are reasons but that 18 with damage did not work for a horn, not all 18's and back then what was available? I know there were many 18 inch horns for pro audio but never for low frequencies.

True, Jeff does have his own custom drivers built. Perhaps he meant for the PA style 18 rather than these tanks of drivers Jeff has.
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post #1004 of 1199 Old 09-30-2013, 07:56 AM
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Originally Posted by RMK! View Post

The too bad would be if Jeff was hanging out on Forums all day long rather than designing and building great audio products. The old yoda guy seems to have limitless time to browse the Forums. That's fine and he does on occasion provide a perspective but he also regularly pulls muscles patting himself on the back as an industry pioneer and master designer (i.e. the Yoda thing).

His blanket statement about horns and driver size needs appropriate caveats but then I just consider the source. rolleyes.gif

Yes I totally agree R. Shipping tons out rather than not speaks for itself. Besides if there was an issue I'm sure we would have heard from you by now with your crazy trigger happy finger on the volume right? I mean what you put these subs through speaks highly of their Tankness quality they have!
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post #1005 of 1199 Old 09-30-2013, 08:08 AM
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The OS has safety measures built into the DSP like limiters and such so we can't blow stuff up. I am sure things can happen but they would be rare. The reason DIYer's blow things up is not because the drivers are not good, it is because we have no protection unless we make an effort to do so. I never blew up a SVS sub either but things can happen. Jeff probably sells more of these on the pro side(guessing here) so we don't hear about those.
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post #1006 of 1199 Old 09-30-2013, 02:11 PM
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Quote:
Originally Posted by MKtheater View Post

That was posted in 2006, maybe horn design has changed? Drivers improved? Too large for venues at the time? I am sure there are reasons but that 18 with damage did not work for a horn, not all 18's and back then what was available? I know there were many 18 inch horns for pro audio but never for low frequencies.
Ok that makes sense then. I don't see posting date from tapatalk for some reason. I'm surprised a moderator hasn't removed the post seeing as it was posted for educational reasons and is out dated now. Erm, assuming it is out dated.
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post #1007 of 1199 Old 09-30-2013, 02:20 PM
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I used folded horn 18's as duals in my room some time ago and they were cheap. I could hit 110 dBs during the pulse scene back then and pin the meter with WOTW and FOTP which was around the same time frame. Those high spl subs is what made me go DIY because I wanted the slam those horns provided but extension down to 15hz so entered my 4 LLT's. They were awesome but still lacked a little midbass slam compared to the folded horns. Mine were the cheap version of OS's before OS were ever made! People used to comment on how could my horns provide so much spl down low and that is when Mark Seaton chimed in because I did not know myself.
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post #1008 of 1199 Old 09-30-2013, 02:41 PM
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Originally Posted by MKtheater View Post

I used folded horn 18's as duals in my room some time ago and they were cheap. I could hit 110 dBs during the pulse scene back then and pin the meter with WOTW and FOTP which was around the same time frame. Those high spl subs is what made me go DIY because I wanted the slam those horns provided but extension down to 15hz so entered my 4 LLT's. They were awesome but still lacked a little midbass slam compared to the folded horns. Mine were the cheap version of OS's before OS were ever made! People used to comment on how could my horns provide so much spl down low and that is when Mark Seaton chimed in because I did not know myself.
got a link? I'd be interested to read that.
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post #1009 of 1199 Old 09-30-2013, 02:46 PM
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Originally Posted by DotJun View Post

got a link? I'd be interested to read that.

That is going back some but I am sure I can dig it up. They were really cheap Madison folded horn subs and I bought them just because they were cheap and wanted to try something new. This was a before The OS and DTS-10 ever were made. They were tuned to 25hz and in a closed chamber so they went deeper than normal horns. I did not even know BFM had a THT at the time which was a 22hz folded sealed horn 15 and the OS is a sealed folded horn high excursion 18. I can understand how they would sound as my Madison cheap subs could move some air! Of course I wanted all so I needed many sealed subs to get that midbass slam and deep bass.
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post #1010 of 1199 Old 09-30-2013, 03:04 PM
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Quote:
Originally Posted by DotJun View Post

Ok that makes sense then. I don't see posting date from tapatalk for some reason. I'm surprised a moderator hasn't removed the post seeing as it was posted for educational reasons and is out dated now. Erm, assuming it is out dated.

Wasn't your link from the BFM forum? I'm pretty sure he is the moderator. You could always ping him for his current take on the subject.

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post #1011 of 1199 Old 10-01-2013, 02:41 PM - Thread Starter
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^
I don't think an in depth examination of an old theorem that has been disproven by several manufacturers products including this Threads SUBject is necessary.

Of course inquiring minds want to get to the bottom of many issues even if they are made of straw . rolleyes.gifwink.gif
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post #1012 of 1199 Old 10-01-2013, 03:41 PM
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I think Bill is referring to a "typical" horn which has the rear of the driver seeing a sealed chamber, and the front seeing the horn path. A tapped horn has the rear of the driver close to the horn opening and front to the horn. Different driver environments between the designs. To visualize easy think of the pressures on a cone pushed to xmax in a sealed box vs. free air.

Danley on tapped horn
http://www.danleysoundlabs.com/danley/wp-content/uploads/2012/01/The-Tapped-Horn.pdf
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post #1013 of 1199 Old 10-02-2013, 11:41 PM
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Quote:
Originally Posted by Luke Kamp View Post

I think Bill is referring to a "typical" horn which has the rear of the driver seeing a sealed chamber, and the front seeing the horn path. A tapped horn has the rear of the driver close to the horn opening and front to the horn. Different driver environments between the designs. To visualize easy think of the pressures on a cone pushed to xmax in a sealed box vs. free air.

Danley on tapped horn
http://www.danleysoundlabs.com/danley/wp-content/uploads/2012/01/The-Tapped-Horn.pdf
But my os is a FLH which goes against Bills claims in that post?
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post #1014 of 1199 Old 10-03-2013, 06:58 AM
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Maybe back then the drivers were not as good or a high excursion driver was not even thought to be put into a horn.
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post #1015 of 1199 Old 10-03-2013, 07:09 AM
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Yea
Quote:
Originally Posted by MKtheater View Post

Maybe back then the drivers were not as good or a high excursion driver was not even thought to be put into a horn.
Yea, maybe so, but now I'm wondering why the post is still up or hasn't been revised since that forum is for his business. I sound like I'm bashing him and/or his company but I'm really not. I just have questions is all.
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post #1016 of 1199 Old 10-03-2013, 07:15 AM
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Originally Posted by DotJun View Post

Yea
Yea, maybe so, but now I'm wondering why the post is still up or hasn't been revised since that forum is for his business. I sound like I'm bashing him and/or his company but I'm really not. I just have questions is all.

I don't think old threads get update except the plan threads. It is obvious things change over time and with Ricci's GH and Jeff's OS there are now 18 inch horns. Danley has 21 inch tapped horns!
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post #1017 of 1199 Old 10-03-2013, 07:31 AM
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Quote:
Originally Posted by MKtheater View Post

It is obvious things change over time
The laws of physics haven't. A quarter wavelength is the same today as it was seven years ago. In a given box size you can make the horn longer, or you may use a larger driver. You can't do both. A nine foot horn will have a corner frequency no lower than 32Hz, no matter what size driver one uses. By the same token a nine foot horn will go to a 32Hz corner frequency, no matter what size driver one uses.
The only engineering reason for going to a larger driver is to realize higher displacement. Tapped horns need higher displacement drivers than sealed chamber horns, so that's a valid reason to use them. I don't do tapped horns. OTOH there comes a point where too much displacement only leads to throat distortion. That isn't a issue when you use a smaller driver in a larger horn, rather than the other way around.
Still IMO the main reason to go to a larger than 15 inch driver in a horn is to make a sale to customers who have no idea how horns work, or what a quarter wavelength is, and insist on having larger than 15 inch drivers. That's not an engineering decision, it's a marketing decision, and I respect that. Business is business.

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The Laws of Physics aren't swayed by opinion.
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post #1018 of 1199 Old 10-03-2013, 07:40 AM
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Originally Posted by rhed View Post

Envy of what? I still would have wanted dual OS...

Why? You have the same output as dual OS above 20hz and 8 OS below! You my friend are ahead of the game!
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post #1019 of 1199 Old 10-03-2013, 08:15 AM - Thread Starter
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Quote:
Originally Posted by Bill Fitzmaurice View Post

The laws of physics haven't. A quarter wavelength is the same today as it was seven years ago. In a given box size you can make the horn longer, or you may use a larger driver. You can't do both. A nine foot horn will have a corner frequency no lower than 32Hz, no matter what size driver one uses. By the same token a nine foot horn will go to a 32Hz corner frequency, no matter what size driver one uses.
The only engineering reason for going to a larger driver is to realize higher displacement. Tapped horns need higher displacement drivers than sealed chamber horns, so that's a valid reason to use them. I don't do tapped horns. OTOH there comes a point where too much displacement only leads to throat distortion. That isn't a issue when you use a smaller driver in a larger horn, rather than the other way around.
Still IMO the main reason to go to a larger than 15 inch driver in a horn is to make a sale to customers who have no idea how horns work, or what a quarter wavelength is, and insist on having larger than 15 inch drivers. That's not an engineering decision, it's a marketing decision, and I respect that. Business is business.

In case you have forgotten (don't worry Bill, it happens to all of us wink.gif) Here is some of what you said in your 2006 post.
Quote:
Too large a cone won't stand up to the pressures of a horn throat. Even fifteens are vulnerable to cone damage, such as this one. Fifteens are OK in horns provided you don't try to get too much output from too few boxes (see Avoid Blown Drivers, http://billfitzmaurice.com/phpBB2/viewtopic.php?t=698), but if you want to push the maximum power possible into only one or two T48 or T60 load them with two twelves rather than one fifteen.

As for eighteens, forget about it. Aside from the fact that they are very vulnerable to damage with high power inputs, they just don't work well in horns. Horn loaded cabinets get low extension via a long path length; an eighteen takes up so much room inside the cabinet that there's not enough room left over for a long horn. Eighteens are only used by those who don't understand how horns work, or those selling their horns to those who don't understand how horns work. Or both.

Do you think Tom Danley knows how horns work? Here are the specs for one of the most powerful commercial TH subwoofers:

The TH221, dubbed “the Cine-Monster” is the only choice for the
tour/event/staging customer who wants high efficiency and 20Hz
performance. Its exceptionally low bass response is also perfect for
the demands of today’s HD commercial theatre or a one-of-a-kind
high-end home theatre.

Boldly, but accurately stated – the Cine-monster has no equivalent!

Specifications
Operating Frequency Range ............................ 22 Hz - 180 Hz - 3 dB
.............................................................. 18.5 Hz – 200 Hz -10dB
Sensitivity @ 1M .............................................................. 109 dBSPL
......................................................................... 116 dBSPL @ 78 Hz
........ (Referenced to 2.83V @1M ½ space, measured as 28.3V @ 10M)
Maximum Output ............................. ... 138 dBSPL/144 dBSPL Peak
........................................ 145 dBSPL/151 dBSPL Peak above 78 Hz
Input Power Ratings .................... 3000 W continuous, 12000 W peak
Nominal Impedance .......Single 2 ohm or 2 x 4 ohm switch selectable
Minimum Impedance .............................................................. 2 ohms
Recommended Processing ............... 20 Hz HP @ 24 dB/Butterworth
Drivers ...................................................... LF 2 x 21” Long excursion
Input Connections ............................................................... 2-NL4MP
Enclosure Material ........... 13ply, 18mm Baltic Birch, polyurea coated


Sure it is a big assed horn and you are correct, the laws of physics don't change (very often) but technology marches on. Improved driver construction and computer modeling makes these larger drivers suitable in a horn (tapped or folded) as evidenced by the two mentioned here.

Thank you for your input and perspective. It is always interesting. smile.gif
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post #1020 of 1199 Old 10-03-2013, 09:20 PM
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Quote:
Originally Posted by Bill Fitzmaurice View Post

The laws of physics haven't. A quarter wavelength is the same today as it was seven years ago. In a given box size you can make the horn longer, or you may use a larger driver. You can't do both. A nine foot horn will have a corner frequency no lower than 32Hz, no matter what size driver one uses. By the same token a nine foot horn will go to a 32Hz corner frequency, no matter what size driver one uses.
The only engineering reason for going to a larger driver is to realize higher displacement. Tapped horns need higher displacement drivers than sealed chamber horns, so that's a valid reason to use them. I don't do tapped horns. OTOH there comes a point where too much displacement only leads to throat distortion. That isn't a issue when you use a smaller driver in a larger horn, rather than the other way around.
Still IMO the main reason to go to a larger than 15 inch driver in a horn is to make a sale to customers who have no idea how horns work, or what a quarter wavelength is, and insist on having larger than 15 inch drivers. That's not an engineering decision, it's a marketing decision, and I respect that. Business is business.
Are you meaning to say that for a given enclosure size there isn't a reason to go with a larger driver, or are you really saying that going over 15" drivers on any size enclosure is not just a bad thing to do but pointless thing to do?

Hey Bill I appreciate you chiming in on this as I find the engineering aspects fascinating.
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