Single sheet TH challenge - Page 183 - diyAudio
Go Back   Home > Forums > Loudspeakers > Subwoofers

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 22nd November 2012, 11:38 PM   #1821
diyAudio Member
 
Join Date: Jan 2011
I mean. It depends on your woodworking skills (gaps between panels, angle cuts spot on? Or slightly off? Do you care how it looks when finished from the outside?)

On my last box New HT subwoofer. Dayton Ref 18"

I didn't use a single screw. Fitment on enery panel was pretty spot on thou.....
  Reply With Quote
Old 22nd November 2012, 11:44 PM   #1822
maxo is offline maxo  United States
diyAudio Member
 
Join Date: Sep 2012
Location: A Hole in Texas
Quote:
Originally Posted by m R g S r View Post
I mean. It depends on your woodworking skills (gaps between panels, angle cuts spot on? Or slightly off? Do you care how it looks when finished from the outside?)

On my last box New HT subwoofer. Dayton Ref 18"

I didn't use a single screw. Fitment on enery panel was pretty spot on thou.....
no wood skills at all, so i think i will need to get scrap cheap wood at the lumber shops and start doing cuts
and make some boxes, or at least practice to make the "box" with the 4 outside panels

Quote:
(gaps between panels, angle cuts spot on? Or slightly off?
nahh i dont think i can make spot on stuff, so super slight off, lol
i dont care how the outside looks, i can use that filler thing to "make up" a bit and tons of duratex
  Reply With Quote
Old 22nd November 2012, 11:47 PM   #1823
maxo is offline maxo  United States
diyAudio Member
 
Join Date: Sep 2012
Location: A Hole in Texas
Holy gucamole
that 18" dayton driver can take 900w rms
geezzz

ahhhh no screws but you use a lot of clamps...
thats the thing
can i avoid clamps using screws ?

Last edited by maxo; 22nd November 2012 at 11:49 PM.
  Reply With Quote
Old 23rd November 2012, 12:02 AM   #1824
diyAudio Member
 
Join Date: Jan 2011
Yes screws are a mechanical fastener.

If you want to bang the box out in a few hours there's no other way to do it without using screws. The way I did that box, glue, position, clamp And let it dry overnight Then move on to the next panel etc.

I deff. Suggest making some practice measurements, markings, cuts, and figments before diving right in to a horn build. There's angle cuts, exact measurements etc etc.

And you can never have enough clamps squares etc so stock up at harbor freight to save a few $$!!
  Reply With Quote
Old 23rd November 2012, 12:05 AM   #1825
maxo is offline maxo  United States
diyAudio Member
 
Join Date: Sep 2012
Location: A Hole in Texas
Quote:
Originally Posted by m R g S r View Post
Yes screws are a mechanical fastener.

If you want to bang the box out in a few hours there's no other way to do it without using screws. The way I did that box, glue, position, clamp And let it dry overnight Then move on to the next panel etc.

I deff. Suggest making some practice measurements, markings, cuts, and figments before diving right in to a horn build. There's angle cuts, exact measurements etc etc.

And you can never have enough clamps squares etc so stock up at harbor freight to save a few $$!!
ic,
harbor freight is second hand right ?
there is not much of wood working stuff around here on my town
so maybe ebay ?
  Reply With Quote
Old 23rd November 2012, 12:09 AM   #1826
diyAudio Member
 
Join Date: Jan 2011
No it's all (mostly) Chinese made stuff. Hit or miss really, but for clamps squares etc its great. You're in the US right? You can order online

Harbor Freight Tools ? Quality Tools at Discount Prices Since 1977
  Reply With Quote
Old 23rd November 2012, 12:21 AM   #1827
maxo is offline maxo  United States
diyAudio Member
 
Join Date: Sep 2012
Location: A Hole in Texas
Quote:
Originally Posted by m R g S r View Post
No it's all (mostly) Chinese made stuff. Hit or miss really, but for clamps squares etc its great. You're in the US right? You can order online

Harbor Freight Tools ? Quality Tools at Discount Prices Since 1977
Yes
Texas
Thanks dude
  Reply With Quote
Old 23rd November 2012, 03:56 AM   #1828
diyAudio Member
 
Matthew Morgan J's Avatar
 
Join Date: May 2011
Location: Arizona
Quote:
Originally Posted by wg_ski View Post
And I'm wondering how the heck you can get a 4" VC driver to have such a low BL.....
Wg_Ski,
On Mr Doom's PRV driver, a BL of 20-ish is not too abnormal for a 15" i think ..... It looks to me like they used a light cone and a VERY tight suspension which is what drove the FS so darn high ..... The tight suspension also drove the QTS up quite a bit ...
It doesn't simulate well at all in an SS15 so that combination wont work, but the PRV driver could work well in other even simpler designs such as a straight tapped pipe, or a partially stuffed QWP with the driver one third of the way down the pipe...Single fold.... Pipe area would need to be almost the same as driver SD (i used 850 in this case)... Pipe needs to be long enough to create a fundamental resonance of 40hz ... Total internal airspace ends up being only about 155 liters which is smaller than the SS15 and could easily be made from one sheet but you are also sacrificing about 3 or 4dbs (at 55hz+) compared to the classic SS15 with 3015lf, but thats just the nature of the beast right? there are always compromises ...
There is a cool feature of the QWP version though, which is the fact that the front of the cone can face forward, and is on the outside of the box like an old scoop cabinet, however since the driver is offset in the pipe and the pipe is partially stuffed there is no issue with the nasty suckout dip in the midbass which the old scoops suffered from, so you can essentially run this design from 40hz all the way to 1khz if the driver has a smooth midrange response....... The midrange would be just "direct radiating" though, so not nearly as efficient as some of the other midrange solutions but it surely is simple, quick and cheap and knocks the socks off of a simple bass reflex/ported box (but larger , but then there's those darn compromises again ) .... By the way , the same QWP should also be possible with 2 Dayton PA-310 12" drivers, giving you a little more cone area and a few more DBs in the midrange ....
  Reply With Quote
Old 23rd November 2012, 04:34 AM   #1829
diyAudio Member
 
bitSmasher's Avatar
 
Join Date: Jun 2012
Location: Sydney.Au
Quote:
Originally Posted by epa View Post
the data looks ok
if you narrow the box you wil always lose low end and/or efficiency.
mods are not needed ,but you wil gain a bit round 60 hz by making s2 a bit smaler.
(try s1 300 and s2 350)
i would put the driver as far back as posible (shorter s1>s2 and longer s4>s5)
--------
if you just rotate the speakerbafle (fixed to the front) ,so s1 becomes 2,5"instead of 3.5",
and put the driver as far back as posible,you get this... [IMG]
Thanks epa, that looks great! Very inspiring... and works well with my thought of running braces in the mouth, now there's space between the driver and the mouth to fit them in.
I hope Santa brings me a stack of plywood for christmas
  Reply With Quote
Old 2nd December 2012, 10:52 AM   #1830
diyAudio Member
 
Matthew Morgan J's Avatar
 
Join Date: May 2011
Location: Arizona
Default 209 liter "SS-18PS76" contender!

Ok, I think i might have come up with a competitive design for JBELL's single sheet challenge! This box may be a good alternative for those who wanted something that has a little more bass extension ..... It has an internal airspace of 209 liters just like Jbell's amazing SS15 but the throat to mouth ratio is much less, allowing me to have a path length which is also less yet still meets the target tuning ... You can squeeze a B&C 18PS76 into this box and with this design's low compression ratio there is little risk of shredding the large diameter cone ...
*The 18PS76 has a low VAS and a low QTS which makes it function well in such a small TH, and with some added series inductance (3 or 4mh total in hornresponse which includes the driver inductance) you can get a pretty smooth response, but the inductor may not actually be necessary in real life with this box ...
*The B&C handles more power, sweeps just as much air (due to it's larger cone area) and retails for less than the 3015LF....
*The bass response "knee" (point at which response falls off like a rock) is more than 10hz lower in frequency compared to an SS15+3015lf which is pretty significant!...
*At the same power level this PS76 design is 4db more sensitive at 40hz and also 2.5db louder at 50hz but sacrifices a little bit of sensitivity to the SS15 around 60-80hz.....
*At 40hz with 600 watts (the rms rating of the PS76) , this box is 5db louder than the SS15 ....
*Overall this PS76 box is flatter according to simulation and has more bass extension ....
*If you want even more extension you can add a Brian Steele styled "DFD" constriction which should flatten the little response bump at 50hz and shift the fundamental resonance down by roughly 5 hertz, fill in the dip at 185hz , and give you a small amount of gain at 80hz and above based on Brian's charts... In theory it should work since this box is basically a scaled up version of Brian's POC#2 (with a slightly shorter path and a tuning/impedance minimum that is identical to the ss15 combined with a throat-to-mouth ratio and compression ratio that matches Brian's POC#2), but of course we wont know for sure if it works until someone builds one .. I am hoping to have access to a cabinet shop here again in the near future and i think i might give it a whirl

BY THE WAY , for a higher powered version you can drop in an 18LW2400 , or an 18TBX100 but they seem to need a little more series inductance ...
Attached Images
File Type: jpg SS-PS76 INPUTS.jpg (82.8 KB, 203 views)
  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
Here is a Challenge latala Solid State 41 12th May 2011 02:13 AM
Renovation Challenge ZirconiumZephyr Multi-Way 16 1st September 2009 09:38 AM
Design Challenge #1 kgillies Subwoofers 12 13th June 2007 04:20 PM
a challenge --or I need help lawrence99 Car Audio 0 9th March 2005 05:44 AM
The challenge ! thylantyr Solid State 51 24th July 2003 09:41 PM


New To Site? Need Help?

All times are GMT. The time now is 05:04 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