Square Pegs - Page 2 - diyAudio
Go Back   Home > Forums > Loudspeakers > Multi-Way

Multi-Way Conventional loudspeakers with crossovers

Please consider donating to help us continue to serve you.

Ads on/off / Custom Title / More PMs / More album space / Advanced printing & mass image saving
Reply
 
Thread Tools Search this Thread
Old 7th August 2012, 04:48 PM   #11
DrDyna is offline DrDyna  United States
diyAudio Member
 
DrDyna's Avatar
 
Join Date: May 2007
Blog Entries: 3
Quote:
Originally Posted by layhzer View Post
How about a low frequency Paraline built into the floor with a 16 foot long exit slot running the length of the room?
I have the weirdest bon....nevermind.

Yeah, I could see this done with a couple of rows of 18s in a floor that was a couple of feet thick. My lord.
__________________
Thou shalt not commit logical fallacies.
https://yourlogicalfallacyis.com/
  Reply With Quote
Old 7th August 2012, 04:49 PM   #12
Bigun is online now Bigun  Canada
diyAudio Member
 
Bigun's Avatar
 
Join Date: Jan 2009
Blog Entries: 2
something other than Youtube would be good.
Attached Images
File Type: jpg Clipboard01.jpg (150.4 KB, 1459 views)
__________________
"The test of the machine is the satisfaction it gives you. There isn't any other test. If the machine produces tranquility it's right. If it disturbs you it's wrong until either the machine or your mind is changed." Robert M Pirsig.
  Reply With Quote
Old 7th August 2012, 05:46 PM   #13
badman is offline badman  United States
diyAudio Member
 
badman's Avatar
 
Join Date: Sep 2003
Location: Sunny Tustin, SoCal
looking forward to device assembly pics. A ring radiator, btw, refers to the diaphragm assembly, it's not radiating in a ring- it's effectively omni, and intended to have less off-axis cancellation by the combined phasing plug and more narrow acoustic source cross section.
__________________
I write for www.enjoythemusic.com in the DIY section. You may find yourself getting a preview of a project in-progress. Be warned!
  Reply With Quote
Old 7th August 2012, 05:49 PM   #14
layhzer is offline layhzer  Canada
diyAudio Member
 
Join Date: Mar 2009
Quote:
Originally Posted by DrDyna View Post
Yeah, I could see this done with a couple of rows of 18s in a floor that was a couple of feet thick. My lord.
Actually, I was thinking about using one shallow mount 12 inch driver. Assuming an Sd of about 95 in^2 and a Paraline "throat" area of 50% of that, then the depth between layers is about 1.25 inches. The total floor thickness, using 1 inch thick wood, then is 1 + 1.25 + 1 + 1.25 + 1 = 5.5 inches. The slot width needs to be about 3.2 inches.
  Reply With Quote
Old 7th August 2012, 06:10 PM   #15
DrDyna is offline DrDyna  United States
diyAudio Member
 
DrDyna's Avatar
 
Join Date: May 2007
Blog Entries: 3
Quote:
Originally Posted by layhzer View Post
Actually, I was thinking about using one shallow mount 12 inch driver. Assuming an Sd of about 95 in^2 and a Paraline "throat" area of 50% of that, then the depth between layers is about 1.25 inches. The total floor thickness, using 1 inch thick wood, then is 1 + 1.25 + 1 + 1.25 + 1 = 5.5 inches. The slot width needs to be about 3.2 inches.
Ah, right. I was thinking of it as multiple units. Considering the size of one of these with a driver that was tuned appropriately low, what popped into my head was similar to a flown array, but built into a floor with a line of openings.

In my head, things are always disproportionately large, it's a man curse.

E.G.: (pic)
Attached Images
File Type: png floor.png (12.3 KB, 1407 views)
__________________
Thou shalt not commit logical fallacies.
https://yourlogicalfallacyis.com/
  Reply With Quote
Old 7th August 2012, 06:33 PM   #16
diyAudio Member
 
Patrick Bateman's Avatar
 
Join Date: Oct 2006
Location: San Diego
Quote:
Originally Posted by layhzer View Post
Great videos. Folding paper is a simple and elegant way to convey the idea.
As much as I value the contributions of experts like Earl Geddes, Tom Danley, Speaker Dave, John K... and others, it is your posts that really get my brain cooking.
Wow, that's a bit humbling! But thank you

Quote:
Originally Posted by layhzer View Post
I see the Paraline as a device to change the radiation pattern of a driver to fit new environments.

How about this for radical? My listening room badly needs a new floor.The "temporary" floor has been in place for 25 years. How about a low frequency Paraline built into the floor with a 16 foot long exit slot running the length of the room? This should provide a different excitation of room modes than a single point source. Better maybe. Worse perhaps.
Actually, that was the idea that got me started on these crazy Paraline experiments.

Here's my situation:

I have my Gedlee Summas in my bedroom. I have three subwoofers, including one that weighs something like 350lbs. (It's documented in the 'night of the living bassheads' thread here on diyaudio.)

Multiple subs *definitely* work - but I'm really sick of having all these ugly subs.

So...

I started these crazy experiments because I was trying to make a Paraline subwoofer. For instance, I can fit a six cubic foot sub under my couch, but the sub has to be less than 10" tall.

A Paraline sub seems like an interesting alternative to the multiple sub approach, because it's not too hard to make the mouth six, eight, or even twelve feet long!

There's one catch though - and that's the humongously long wavelengths. For instance, this experiment started when I was trying to make a 40hz Paraline. Due to the radial expansion of the Paraline, a 40hz Paraline subwoofer ends up being over 7' x 3.5'!

So the reason my Paraline has a square mouth instead of a long skinny one is that I was stacking a Paraline on a Paraline. By doing that, you cut the footprint in half.

Quote:
Originally Posted by layhzer View Post

Not radical enough? How about a tapped low frequency Paraline. The same as above but using the radiation from the back of the driver to aid the radiation from the slot.

Still not radical enough? I know a low frequency Paraline won't act exactly like a double bass array but what about a "launcher" Paraline on the floor and a "catcher" Paraline on the ceiling.

Other than the obvious issues, the real problem is modelling the performance of the system. Anyone know of any tool that would help with this type of analysis?
  Reply With Quote
Old 7th August 2012, 06:44 PM   #17
diyAudio Member
 
Patrick Bateman's Avatar
 
Join Date: Oct 2006
Location: San Diego
Quote:
Originally Posted by Nissep View Post
My understanding of the paraline is that the sum of the diferent pathlenght is always konstant if you dont want it to have a different shape of the waveform as i leaves the exit.

A neat trick you can use is to use a small lenght of string and fold it in half. One end you attach i the middle of the divice, the entrance for the speaker. And the other end of the string you move around on the edge of the shape of the exit "port".
And with the string folded and pulled straight out from the middle you will get the shape of the first cutout. The shape of the exit dont matter as long as the patch lenght is the same.
And a string cant change its lenght..
This is a great idea! Using string to trace the Paraline has a ton of benefits:
  • If you use graph paper and fold it like I did, you can't account for the thickness of the wood. Ignoring the wood thickness isn't a humongous deal if the wood is only 1/4" thick, but it could still lead to pathlength differences that could introduce comb filtering at high frequencies. Your string trick eliminates that error.
  • If you use string, you can use some really bizarre shapes for the Paraline. For instance, one idea I had was to make a hemispherical or pyramid shaped Paraline. (This would be for car audio, where we're severely limited on space, since we put speakers under the dash or in the door.) Jason Winslow managed to build a Unity horn that was small enough to fit in a car door!
  • The string trick is about a million times simpler to visualize than using my Excel spreadsheets. I have some spreadsheets I've published which will calculate the Paraline dimensions, but it's a lot easier to 'grok' the horn bends with a piece of string and a piece of plywood.

And speaking of visualizing the Paraline folding, here's a video I made of Nissep's string trick:

Map a Paraline with string - YouTube

VTC has an animation that shows the Paraline peeled apart like layers in a sandwich. This is required viewing for any of this to make sense:

http://www.vtcproaudio.com/paraline02.html

After you watch my videos, and the VTC animation, it should give you some ideas on how to fold a horn like you're folding a pancake. The key dimensions are the radius of the 'pancake' and the height of the pancake. The radius is equivalent to the depth of a conventional horn, and the height of the pancake dictates two things. First, it sets your upper frequency limit. Second, it dictates the area of the horn. (But note that the horn expands, just like a conical horn, because each concentric ring has a greater area than the ring that preceded it.)


Last edited by Patrick Bateman; 7th August 2012 at 07:00 PM.
  Reply With Quote
Old 7th August 2012, 06:47 PM   #18
DrDyna is offline DrDyna  United States
diyAudio Member
 
DrDyna's Avatar
 
Join Date: May 2007
Blog Entries: 3
Quote:
Originally Posted by Patrick Bateman View Post
There's one catch though - and that's the humongously long wavelengths. For instance, this experiment started when I was trying to make a 40hz Paraline. Due to the radial expansion of the Paraline, a 40hz Paraline subwoofer ends up being over 7' x 3.5'
That's one of the reasons this grabbed my attention is the thickness. At the thicknesses needed, one could hide this in walls, in floors, behind things, hung on walls, etc etc. It seems really flexible.
__________________
Thou shalt not commit logical fallacies.
https://yourlogicalfallacyis.com/
  Reply With Quote
Old 7th August 2012, 06:52 PM   #19
layhzer is offline layhzer  Canada
diyAudio Member
 
Join Date: Mar 2009
Quote:
Originally Posted by DrDyna View Post
Ah, right. I was thinking of it as multiple units. Considering the size of one of these with a driver that was tuned appropriately low, what popped into my head was similar to a flown array, but built into a floor with a line of openings.
My fault. I wasn't clear. My idea is to use the eye shaped Paraline, as shown in the patent, but scaled to room size. Not the square opening version that is in the video.
  Reply With Quote
Old 7th August 2012, 07:00 PM   #20
DrDyna is offline DrDyna  United States
diyAudio Member
 
DrDyna's Avatar
 
Join Date: May 2007
Blog Entries: 3
Quote:
Originally Posted by layhzer View Post
My fault. I wasn't clear. My idea is to use the eye shaped Paraline, as shown in the patent, but scaled to room size. Not the square opening version that is in the video.
Ah. I think the tuning has something to do with the throat, if you scaled the whole thing with a single driver to 10 or 12 feet, wouldn't you end up with a horn that was tuned to like, 10 cycles?

You would probably have to figure out how you wanted to tune it and then use however many units you'd have to use to fill the space.

Bah, getting carried away again. Hoping to see some more detailed drawings of what Patrick has done here.
__________________
Thou shalt not commit logical fallacies.
https://yourlogicalfallacyis.com/
  Reply With Quote

Reply


Hide this!Advertise here!
Thread Tools Search this Thread
Search this Thread:

Advanced Search

Posting Rules
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is Off
Trackbacks are Off
Pingbacks are Off
Refbacks are Off


Similar Threads
Thread Thread Starter Forum Replies Last Post
My Wave Isn't Square. Troncones Tubes / Valves 186 28th August 2014 12:04 PM
EICO 666 meter needle moves too fast/pegs too hard...help? jasonguitar Tubes / Valves 3 15th September 2010 01:58 AM
What gives with this square wave? martyh Tubes / Valves 23 21st January 2010 09:22 PM
Why are almost all sub boxes square elambert Subwoofers 12 28th May 2005 08:49 PM
Square wave Prune Everything Else 11 28th June 2004 06:17 AM


New To Site? Need Help?

All times are GMT. The time now is 12:54 AM.


vBulletin Optimisation provided by vB Optimise (Pro) - vBulletin Mods & Addons Copyright © 2014 DragonByte Technologies Ltd.
Copyright 1999-2014 diyAudio

Content Relevant URLs by vBSEO 3.3.2