Ijit Mk. II -- help me actually build a TH! - 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 3rd May 2014, 10:56 PM   #1
diyAudio Member
 
Soldermizer's Avatar
 
Join Date: Feb 2012
Location: Tamper, FL, USA
Default Ijit Mk. II -- help me actually build a TH!

Ok summer is here (at least spring semester is done) and the ijit begins to fidget -- what, oh what, to build next? I still would like to build a real TH with my 2x 15" Alpines. For weeks, they have been working well in the Frankenclosure which apparently is quite close to what an optimum Vented for two of these Alpines would be (more on that later). Could it be built better? Oh yes, unless you idea of "stylish" is a 2 ft cube with a 4 ft 12" sonotube port coming out the top

All along I've been trying different ideas in Hornresp. Problem: I have a hard time beating the optimum vented box. Say it ain't so! I thought the TH is the ultimate? Dare I build something as big as 2000 L just for a few more dB of sensitivity? Maybe "yes".

Everything is of course negotiable. But having learned some stuff in the past year (I hope) here are some design goals:

1. I like dual drivers, push-push for the force canceling. Distortion-canceling optional.

2. Conventional construction materials are acceptable. I am willing to consider normal things like Baltic Birch or MDF. Extensive research has shown that alternatives are not all that cheaper, much expensiver, and in many cases dubiouser

3. Specs? Oh yes, the specs! I don't need infra-sonic. But for these drives (Fs=27 Hz), EazyHorn suggests 18 Hz. I want it to be at least as sensitive as a comparable vented would be. Many sims will easily get into low 20s.

4. Size is not really a concern. It won't be moved much after it's built. Not by one person anyway. Utility wise, I would either want it sized so it can be a pedestal/base for my video and other junk OR be a coffee table height (say 2'). Problem: I'm not sure I want a coffee table that is 2' high by 7' x 5' (I calc. ~ 70 cu. ft for the biggest cabinet so far).

It's rainy season here in FL, so I should be able to gondoleer any big needed pieces of wood from the store to my home.
__________________
Don't worry what other people think. They don't do it very often. Hey! I said "Think for yourself!!!"
  Reply With Quote
Old 3rd May 2014, 11:07 PM   #2
sine143 is offline sine143  United States
diyAudio Member
 
Join Date: May 2010
post T/S specs for drivers
  Reply With Quote
Old 3rd May 2014, 11:27 PM   #3
tb46 is offline tb46  United States
diyAudio Member
 
Join Date: Jan 2006
Location: Texas
Hi soldermizer,

Are you still using the Alpine SWS-15D4? Could you, please, post your reference vented box Honresp design? Do you want the same low end, e.g.: -3dB corner?

Regards,
__________________
Oliver
  Reply With Quote
Old 4th May 2014, 12:43 AM   #4
zobsky is offline zobsky  India
diyAudio Member
 
zobsky's Avatar
 
Join Date: Mar 2002
Location: Dallas, Tx, USA
Perhaps a corner pillar type TH.? They usually take up the least amount of floor space.
__________________
"Any fool can know. The point is to understand" - Albert Einstein
  Reply With Quote
Old 4th May 2014, 03:34 AM   #5
diyAudio Member
 
Soldermizer's Avatar
 
Join Date: Feb 2012
Location: Tamper, FL, USA
Default Links and more rambling

Yes, pair of SWS-15D4.
Download specs here:
Alpine Electronics of America, Inc.

My latest hornresp.dat file downloadable at:

http://bmmoser.myweb.usf.edu/shared/TEMP/Hornresp.dat

TB46, the "AS BUILT" sims very close to my "optimal" vented box. Yes, same or better low corner please. At the very least two easy options are:

1. Build a TH that will be perhaps 600L and give 2-3 dB better sensitivity. Low corner about 23 Hz.

2. If I decide vented is the best, build a less hideous (non-Frankenclosure) box (230 Litre more or less).

A corner is available, but space is not an issue. A TH does not benefit from a corner does it?

Between the two, I'd like to have a "coffee table" (cables not a big issue); on the other hand here is a photo of my current "entertainment center" so you can see there is a just a bit of room for improvement
Attached Images
File Type: jpg video center.jpg (28.2 KB, 285 views)
__________________
Don't worry what other people think. They don't do it very often. Hey! I said "Think for yourself!!!"
  Reply With Quote
Old 4th May 2014, 06:20 AM   #6
GM is online now GM  United States
diyAudio Member
 
GM's Avatar
 
Join Date: Jun 2003
Location: Chamblee, Ga.
Hmm, you're describing a TH sim I did awhile back.........

GM
Attached Files
File Type: txt SWS15D4_TH.txt (954 Bytes, 25 views)
__________________
Loud is Beautiful if it's Clean! As always though, the usual disclaimers apply to this post's contents.
  Reply With Quote
Old 4th May 2014, 02:53 PM   #7
zobsky is offline zobsky  India
diyAudio Member
 
zobsky's Avatar
 
Join Date: Mar 2002
Location: Dallas, Tx, USA
Any basshorn variant benefits from a corner
__________________
"Any fool can know. The point is to understand" - Albert Einstein
  Reply With Quote
Old 4th May 2014, 05:39 PM   #8
tb46 is offline tb46  United States
diyAudio Member
 
Join Date: Jan 2006
Location: Texas
Hi Soldermizer,

GM's suggestion in Post #6 should get you there, if I compared everything correctly its SPL will be a little higher than the response of the BR when both boxes are driven to Xmax.

I'll attach one more suggestion based on a simple single fold box (that's what zobsky suggested in Post #4) that trades of SPL for low frequency extension. For an internal duct width (constant) of 16" the respective S1 duct height is 6", S2 is 6.4", S3 is 14.4" and S4 is 16"; L12 is 7.875", L23 is 157.480" and L34 is 31.496"; or in other words a simple wedge 16"wide going from 6" to 16". For coffee table use: fold more than once.

From the simulations it looks like the Alpine SWS 15D4 is best suited for the BR, but will work in other enclosures too.

Regards,
Attached Images
File Type: jpg Alpine_SWS_15D4_GM TH v. BR_SPL.jpg (18.9 KB, 261 views)
File Type: jpg Alpine_SWS_15D4_TH_Input.jpg (24.5 KB, 255 views)
__________________
Oliver
  Reply With Quote
Old 4th May 2014, 07:13 PM   #9
bjorno is offline bjorno  Sweden
diyAudio Member
 
Join Date: Mar 2005
Location: Jacobsmountain
Send a message via MSN to bjorno
Hi all,

FYI: A somewhat smaller Design:

b
Attached Images
File Type: jpg Alpine-SWS-T-QWP.JPG (783.4 KB, 252 views)
  Reply With Quote
Old 10th May 2014, 01:44 PM   #10
diyAudio Member
 
Soldermizer's Avatar
 
Join Date: Feb 2012
Location: Tamper, FL, USA
Default First tangent

This thread began entirely too seriously for my usual levity

I was reading on CNET this morning. For a techie, this is much akin to the thrill of receiving a DAK catalog back in the 1980s, and produces the same endorphin rush, and impairment of spending restraint, as dropping off an intoxicated sailor with a fat wallet in front of the city's brothel

Onward to today's silly idea: perhaps my future subwoofer can be adapted so as to have the features of the below-described toy?

The CATable is a workspace designed for your feline friend - CNET

As I have complained in a prior thread, back when I was new at this DIY stuff and life was simple (a 12-foot Sonotube with a driver jammed in one end), I wrote about how some of the cats liked to hide inside it. One cat even didn't mind staying inside, at least at lower volumes.

Since my latest ijit inspirationis for a coffee table sized TH, could it be adapted so that it is a cat toy also? A single fold might be wide enough for the little devils to explore. Also I have "sourced" Alpine woofers which are plastic cone and thus not attractive and also resistant to potential clawing. Win-win!
__________________
Don't worry what other people think. They don't do it very often. Hey! I said "Think for yourself!!!"
  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
Help the Ijit -- build his 1st Tapped Horn Soldermizer Subwoofers 123 16th April 2014 01:04 AM
Help the Ijit -- Build a "Bose Cannon" knockoff Soldermizer Subwoofers 108 19th February 2014 07:17 PM
Classic Aragon (2004, 2004 MK II, 4004, 4004 MK II ) problems, experience and repairs MagicMarksy Solid State 1 22nd May 2010 03:36 PM


New To Site? Need Help?

All times are GMT. The time now is 05:33 PM.


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