The Legend of El Pipe-O - AVS Forum
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post #1 of 17 Old 02-15-2014, 04:46 PM - Thread Starter
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Only for people with High ceilings, haha.

Just scroll down to Page 8

http://www.firstwatt.com/pdf/art_elpipeo.pdf
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post #2 of 17 Old 02-15-2014, 04:47 PM
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Interesting design for sure. I will have to peruse the doc more thoroughly.

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post #3 of 17 Old 02-15-2014, 05:08 PM
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what would something like this offer compared with a ported enclosure of the same tune?

jack bouska runs them (or at least he did in his supersystem).

http://www.audioheritage.org/vbulletin/showthread.php?12126-DIY-Axially-symmetric-oblate-spheroid-CD-waveguides-in-solid-Oak&p=123614&viewfull=1#post123614

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post #4 of 17 Old 02-15-2014, 05:14 PM - Thread Starter
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Later on the article says that it works almost as good without the manifold and just 1 driver in each "Pipe"
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post #5 of 17 Old 02-15-2014, 05:17 PM - Thread Starter
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Quote:
Originally Posted by LTD02 View Post

what would something like this offer compared with a ported enclosure of the same tune?

jack bouska runs them (or at least he did in his supersystem).

http://www.audioheritage.org/vbulletin/showthread.php?12126-DIY-Axially-symmetric-oblate-spheroid-CD-waveguides-in-solid-Oak&p=123614&viewfull=1#post123614

El PIPE-O is just a straight tube with out the Folded Horn, sortofa simple Sonotube really.
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post #6 of 17 Old 02-15-2014, 05:34 PM - Thread Starter
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Interesting design for sure. I will have to peruse the doc more thoroughly.

He picked 12ft tube for a reason. I have room to mount 1 or 2 horizontally haha. Who'll be the first?
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post #7 of 17 Old 02-15-2014, 05:34 PM
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so to investigate this, i looked at the 2242 driver in a ported cab. this response:


then i created a quick pipe-o and got this schlock:



then seeing some potential here, i modified it to create this:



so it looks like the pipe-o can pick up a little sensitivity vs a ported cab, but you have to do it right.

:-)

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post #8 of 17 Old 02-15-2014, 05:42 PM
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oops, driver was pointed wrong way. here is pipe-o




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post #9 of 17 Old 02-15-2014, 05:47 PM
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and a pipe-o with a flare starting at 1/2 sd and ending at 2x sd

that doesn't look too bad actually.



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post #10 of 17 Old 02-15-2014, 06:21 PM - Thread Starter
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After rereading, always important for forgetful me, they started talking about 14' being quarter wave of 20Hz BUT they ended up using 12' sections of Sonotube...
Then modified the design for 1 speaker and a 10' section (cut 2' off the end in the box) which they were happy with but was not the ideal design.
Then suggested (last page of article) making 2 six footers from a 12' section of eight inch sonotube and using 8' woofers with a 40Hz resonant Freq.
So there were 3 design experiments. The 8" six footers should go great next to the big boys huh?
I think I can handle the dual eights as I have a loose pair that are currently "between boxes" haha.

Edit: Nope, I have wrong ones but these Fenders may work,
These are not exactly high powered speakers but... http://www.parts-express.com/fender-8-full-range-speaker-8-ohm--299-079
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post #11 of 17 Old 02-16-2014, 07:47 PM
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Originally Posted by LTD02 View Post

oops, driver was pointed wrong way. here is pipe-o

That's terminus output alone. You have to do combined response to see actual response.

BUT with these sonotube transmission lines that have the driver and port so far apart the actual response at any given position could be anywhere between the combined response with 0 path length difference (which only applies if you measure from a spot equidistant from both ends) or the response on the terminus end (as you showed) or the response at the driver end (which is significantly different than both) depending on where you are in relation to the sub. The room will even it out to some degree but it's still a mess.

These long straight (constant csa) transmission lines with driver and terminus so far apart are just a bad idea (IMO). Adding a bit of taper to the line (like your example, although it's also shown as terminus output only) and doing a simple single fold to put the driver and terminus closer together is much better (again IMO). Do that and throw in a bit of stuffing and you can get almost ruler flat response over a much wider bandwith no matter where you stand in relation to the sub, unlike El Pipe-o.
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post #12 of 17 Old 02-16-2014, 08:11 PM
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Just to be more clear, here's a few pics.

Graph 1 - combined response +300 cm
Graph 2 - combined response 0 cm
Graph 3 - combined response -300 cm

So if you built this, laid it out flat on the ground and measured from different locations in relation to the sub, this is what you would get from the terminus end, the middle and the driver end. As you walk around the sub you would get VERY different response due to the driver and terminus being so far apart. Put it in a room and the room will even this mess out to some degree (and add it's own wild influence to the mix) but it's still a mess and a bad idea (IMO).

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post #13 of 17 Old 02-16-2014, 08:30 PM
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ah, i see. thanks for clearing that all up.

nice work.

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post #14 of 17 Old 02-17-2014, 12:21 AM
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Quote:
Originally Posted by Bob7145 View Post

Only for people with High ceilings, haha.

Just scroll down to Page 8

http://www.firstwatt.com/pdf/art_elpipeo.pdf
I'm failing to see the attraction in it except perhaps the massive size to impress people.
You can do far more in much less volume.
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post #15 of 17 Old 02-17-2014, 01:12 AM - Thread Starter
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Did you read the article? It was just an experiment for fun about 12 years ago.
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post #16 of 17 Old 02-17-2014, 02:58 AM
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Quote:
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Did you read the article? It was just an experiment for fun about 12 years ago.
I read it when it first came out, and it wasn't particularly impressive then. And since then the world has moved on with better drivers, EQ and amplifiers.
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post #17 of 17 Old 02-17-2014, 05:45 AM
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Quote:
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Did you read the article? It was just an experiment for fun about 12 years ago.
I read it, and if it had been my experiment I would have chalked it up to experience and moved on. Nellie's as good as they get with amplifier design, but where speakers are concerned he's as much a hacker as I am playing golf. That doesn't mean I'll ever give up playing golf, but I'll never make a living doing it either.

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