Best design program - diyAudio
Go Back   Home > Forums > Loudspeakers > Full Range

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 14th January 2013, 11:12 AM   #1
diyAudio Member
 
Join Date: Dec 2012
Default Best design program

I saw this project and really liked it: "nanoTower" - Tang Band W3-881SI

It's super simple and seems fun (not to mention cheap). I would like to challenge myself a little from a woodworking perspective though, see what I'm able to do. What would be a good program that would allow me to take that project and add a lot of complexity to the box with good modeled results still. I'd like to be able to angle the front baffle, maybe protrude it out a bit, add internal bracing, mess with port size and location.

I have vaguely read that some programs don't calculate ports very well, so that's why I'm asking.
  Reply With Quote
Old 14th January 2013, 11:40 AM   #2
xrk971 is offline xrk971  United States
diyAudio Member
 
xrk971's Avatar
 
Join Date: Oct 2012
Location: Virginia
For modeling bass reflex cabinets, WinISD works well. In the case of Cogitech's nanotower, there is some accidental mass loaded transmission line (MLTL) effects happening. To model that properly, you will need to use Martin J King's Mathcad worksheets which can account for fairly complex geometries and include effects of damping using stuffing. You can also model a lot of the simpler box or horn geometries with HornResp. For really complex geometries, really, the only program is Akabak. Akabak is very powerful but takes some finesse and expertise to use and can do a lot. All except the MJK programs are free. I would play around with HornResp first if you are interested in getting started and want to do more than a bass reflex.
Good luck.
  Reply With Quote
Old 20th January 2013, 12:15 PM   #3
diyAudio Member
 
Join Date: Dec 2012
So I downloaded all of those programs, and WinISD was quite easy to get the hang of, but MathCAD is much more complex and I found myself quite lost.

I wanted to make a few simple changes to the Nano-tower design to better fit my needs and design likes (that sounds weird but you get it).

Anyways I modeled up what I'm thinking for a cabinet. I did my best to make the model as similar looking to the actual cuts of wood I'd make as possible, although Maya isn't really designed for that.

Basic dimensions are - width: 4.5" - depth: 9.5" - height in front: 42" with a slope down in the rear. I'm not completely sure the amount of slope, although similar to the model. The slope is created cutting arches that are the width of the mdf, 3/4". I'll stack and glue the arches, then sand them smooth. The plan was to just leave the bottom side of them stepped. It's a bit hard to see in the pics. That's a decision MathCAD or your guys experience could help with.
And the port was moved to the front. It will be 3" not 3.5", and I was planning on just using the sides and bottom of the cabinet as 3 of the walls.

Anyways, I was hoping for some experienced thoughts and ideas before I start cutting the wood. Is the cabinet narrow enough for it to not matter or do I need some cross bracing? Will the arch on top create problems? Does the port need to be different?
If somebody is feeling super extra nice some decent guides to help me learn how to input this data into MathCAD would be great, or maybe even specific help

Click the image to open in full size.
Click the image to open in full size.
  Reply With Quote
Old 21st January 2013, 09:30 AM   #4
xrk971 is offline xrk971  United States
diyAudio Member
 
xrk971's Avatar
 
Join Date: Oct 2012
Location: Virginia
Nice work on the design and in downloading all the programs. Is there a reason you have it so tall? This will make the speaker very tippy unless you put wide legs or weight the bottom. The WinISD is giving you Bass Reflex behavior only, in reality it will go much lower. If you want to try this out quickly and cheaply, make it out of foam core board first before cutting wood. You will get an idea of the sound and how deep the bass is.
  Reply With Quote
Old 21st January 2013, 09:45 AM   #5
diyAudio Member
 
Join Date: Dec 2012
The reason for the height is that it puts the driver exactly at ear level in my office chair. I was planning on adding some molding to the bottom that would stick out about 1/2" all the way around and I already have spikes that i would place in that. I'd think tipping wouldn't be an issue with that on wood floors, don't plan to bump into them too much
  Reply With Quote
Old 21st January 2013, 09:58 AM   #6
frugal-phile(tm)
diyAudio Moderator
 
planet10's Avatar
 
Join Date: Oct 2001
Location: Victoria, BC, NA, Sol III
Blog Entries: 5
That simulated response is REALLY ugly. But it is not accurate as the height + the vent at the bottom make it an ML-TL. With that much height you will be tuning the poor little driver too low. And in an ML-TL, especially of that height (given the driver), you should really be taking advantage of offset.

If you want the box that tall you'd be much better making a false bottom and fill it with sand.

I'd also use good plywood.

MatCad is vry complex, but its purpose is to run Martin's worksheets.

dave
__________________
community sites t-linespeakers.org, frugal-horn.com, frugal-phile.com ........ commercial site planet10-HiFi
p10-hifi forum here at diyA
  Reply With Quote
Old 21st January 2013, 10:22 AM   #7
diyAudio Member
 
Join Date: Dec 2012
I am quite new at all of this Dave, so go easy on me. By offset you are referring to not centering the driver horizontally, in order to reduce issues with diffraction? My thoughts were that since the cabinet was so narrow, and with a good 1/2" roundover on all front edges I wouldn't have any issues with that. Or do you mean vertical offset, lowering the driver in the cabinet?

I was thinking since you say that tuning the driver that low is not good, I would reduce the depth from 9.5" to 6", which reduces the volume from .52 ft^3 (measured incorrectly above) to .29 ft^3. In keeping the same .75" x 3" port, making it 3.75" deep I get the same basic shape of the frequency response curve, but much flatter with a 2.5db rise, but no dip like above. Puts the tuning frequency at 62hz
  Reply With Quote
Old 21st January 2013, 06:15 PM   #8
frugal-phile(tm)
diyAudio Moderator
 
planet10's Avatar
 
Join Date: Oct 2001
Location: Victoria, BC, NA, Sol III
Blog Entries: 5
Quote:
Originally Posted by SneakoBaggin View Post
By offset you are referring to not centering the driver horizontally, in order to reduce issues with diffraction?
No. Offset the driver vertically to kill the 1st undesirable harmonic in the TL, allowing for less damping and more bottom. In a line like this typically near a 1/3 of the way down (exact placement is fairly important)

Quote:
I was thinking since you say that tuning the driver that low is not good, I would reduce the depth from 9.5" to 6", which reduces the volume from .52 ft^3 (measured incorrectly above) to .29 ft^3.
Because the aspect ratio of the cabinet is so tall, the tuning of the driver is dominated by the boxes' height. Anything you do in WinISD will not tell you what is happening, as it assummes a box that is much closer to a cube... once one dimension starts becoming significantly larger then the others the box starts transforming from a BR to a mass loaded transmission line.

Another thing to consider is that it is not really a good idea to tune a driver to less than 0.71 x the Fs = 75 Hz with this driver. Also keep an eye on excursion.

dave
__________________
community sites t-linespeakers.org, frugal-horn.com, frugal-phile.com ........ commercial site planet10-HiFi
p10-hifi forum here at diyA
  Reply With Quote
Old 21st January 2013, 06:28 PM   #9
frugal-phile(tm)
diyAudio Moderator
 
planet10's Avatar
 
Join Date: Oct 2001
Location: Victoria, BC, NA, Sol III
Blog Entries: 5
Doing some sims, and ignoring what might be possible with a TL or horn, there is no vented enclosure that works (Qt is too high), 3 to 4 litre sealed is what i'd do. Also no matter what i do, with 1 W in, xMax is exceeded at 300 Hz.

dave
__________________
community sites t-linespeakers.org, frugal-horn.com, frugal-phile.com ........ commercial site planet10-HiFi
p10-hifi forum here at diyA
  Reply With Quote
Old 21st January 2013, 06:42 PM   #10
diyAudio Member
 
tuxedocivic's Avatar
 
Join Date: Jan 2011
Location: Ladysmith, BC
If you have the budget, I added a woofer from 300hz and down with this little Tang Band. Now that I've proven it with an active cross over, I was going to start working on a passive to free up my minidsp and some amp channels. But that would make the enclosure way wider. But it would also solve the issues Dave has pointed out with that little guy wanting a sealed box and a 300hz lower limit.
  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
Crossover design program availability? sdad Multi-Way 4 11th April 2011 12:18 PM
Horn Design Program jhelm_waterw Multi-Way 1 13th March 2007 03:39 PM
Which enclosure design program? georgehifi Multi-Way 6 8th August 2006 09:36 PM
WinISD enclosure design program SubNut Multi-Way 3 24th September 2001 09:24 PM


New To Site? Need Help?

All times are GMT. The time now is 07:26 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