Go Back   Home > Forums > >
Home Forums Rules Articles diyAudio Store Blogs Gallery Wiki Register Donations FAQ Calendar Search Today's Posts Mark Forums Read

Multi-Way Conventional loudspeakers with crossovers

Help me design a mini-tower TMM DCR speaker...
Help me design a mini-tower TMM DCR speaker...
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 28th June 2015, 12:43 AM   #1
ChuckORWC is offline ChuckORWC  United States
diyAudio Member
 
Join Date: Nov 2014
Default Help me design a mini-tower TMM DCR speaker...

Iím looking for some advice/guidance on a future speaker project. Iíve got a pretty good idea of what I want, but Iíd like some input from some of you who actually know a thing or two about speaker design, as I pretty much know nothing. In spite of that fact, Iíve come up with some ideas that I think may result in a respectable pair of speakersÖ letís see if you agree.

Goals:
  • great sound
  • mini tower form factor, TMM driver arrangement
  • inexpensive
  • high WAF
  • good sensitivity (will be driven by ACA mono blocks)

The preliminary design Iíve come up with would employ two Silver Flute W14RC25-08 5-1/2Ē wool cone drivers per speaker with a Vifa DQ25SC16-04 1Ē titanium dome tweeter. The box would be a double chamber reflex as described by Claudio Negro HERE..

Now Iím going to just throw out some thoughts, ideas, and questions. Again Iím not fluent in speakerese so forgive me if my Qts offends your X-max or youíre baffled by my baffle step .
  • If I understand basic BR design correctly, I would simply double the volume for a single-driver enclosure for the desired F3. Then, for the DCR volumes Iíd divide that total volume up 2:1 with the drivers mounted in the larger chamber. Is this correct?
  • The above applies to straight 2-way design I presume. How would the DCR volumes change when using a 2.5-way topology?
  • My understanding is that paralleling two drivers halves the impedance and increases the sensitivity by some factor. I presume that changes when going 2.5-way. Would it be preferable to use the 4-ohm version of these drivers if I were to go with 2.5-way?
  • Would modifying both of the woofers (in 2-way) or just the mid-woofer (2.5-way) with phase plugs help to improve the upper range of the woofers and permit a higher crossover point?
  • Iím planning on using 3/4Ē MDF. Iíve got some ideas with regards to construction, damping, etc., which will be discussed later.
  • Iím sure Iíll need some help with crossover design, but weíll crossover that bridge when we get there.
  • Iíve ordered a Dayton IMM-6 measurement mic. Itís cheap as all get-out and certainly not pro quality, but with the AudioTools app I should be able to get some useable measurements when that time comesÖ

That should be enough to get the discussion rolling. Iím open to recommendations for different drivers, etc., keeping in mind that I want to keep costs down. Iím not interested in being told that I really should start with a kit, or an open baffle, or a full range, etcÖ I know there are a lot of great, established designs out there but Iíd like to explore the feasibility of this design, as preliminary as it is. I like a challenge.

It will be a while before Iíll be able to actually work on this project due to other bigger projects, so if this discussion produces any useable info and someone else wants to be the guinea pig, be my guest!
Attached Images
File Type: jpg Speaker.jpg (40.1 KB, 118 views)
  Reply With Quote
Old 28th June 2015, 01:20 AM   #2
Sonce is offline Sonce  Macedonia
diyAudio Member
 
Join Date: Jan 2014
Location: Macedonia
  • If I understand basic BR design correctly, I would simply double the volume for a single-driver enclosure for the desired F3. Then, for the DCR volumes I’d divide that total volume up 2:1 with the drivers mounted in the larger chamber. Is this correct?
    Yes.
  • The above applies to straight 2-way design I presume. How would the DCR volumes change when using a 2.5-way topology?
    No change. In many ways, 2.5 topology is better than simple two-in-parallel (in the TMM configuration).
  • My understanding is that paralleling two drivers halves the impedance and increases the sensitivity by some factor.
    Yes.
    I presume that changes when going 2.5-way.
    Below the crossover point (between the woofers) sensitivity increases the same as in two parallel woofers, above is the same as in one woofer alone.
    Would it be preferable to use the 4-ohm version of these drivers if I were to go with 2.5-way?
    No.
  • Would modifying both of the woofers (in 2-way) or just the mid-woofer (2.5-way) with phase plugs help to improve the upper range of the woofers and permit a higher crossover point?
    Do not modify the woofers!

DCR has no real advantage over conventional bass-reflex, especially with two 5" drivers. DCR is good (maybe) only for single 3" or 4" driver.

Last edited by Sonce; 28th June 2015 at 01:23 AM.
  Reply With Quote
Old 29th June 2015, 06:54 PM   #3
ChuckORWC is offline ChuckORWC  United States
diyAudio Member
 
Join Date: Nov 2014
Thanks Sonce,

One of the reasons I'm considering DCR is to minimize the negative effects of a long, skinny BR chamber. Would it be a better option to simply have two separate ported chambers? If I went with a single chamber, the inner dimensions based on Madisound's suggested box volume would be approx. 5.5" x 32" x 8".
  Reply With Quote
Old 29th June 2015, 08:44 PM   #4
Sonce is offline Sonce  Macedonia
diyAudio Member
 
Join Date: Jan 2014
Location: Macedonia
It is very difficult to divide the long skinny box in two equal volumes, with two woofers mounted on the very top of the box, so go for one BR chamber. There will be a half-wave resonance along the 32" dimension, but it can be tamed with a small chamber on the top of the box (behind the tweeter) acting as Helmholtz absorber at 212 Hz. New internal height of the box should be 32" plus the height of the Helmholtz absorber. Increase slightly the width of the box, to reduce the 8" depth which in turn will reduce internal resonance, because 8" is exactly 1/4 of 32".

Another solution is to move down the bottom woofer, about at half of the box height, with an internal divider (just behind the bottom woofer) mounted at 45 degrees - the box now is divided in two equal volumes, with some additional benefit from the non-parallel internal divider.
  Reply With Quote
Old 29th June 2015, 09:02 PM   #5
planet10 is offline planet10  Canada
frugal-phile(tm)
diyAudio Moderator
 
planet10's Avatar
 
Join Date: Oct 2001
Location: Victoria, BC, NA, Sol III
Help me design a mini-tower TMM DCR speaker...
Quote:
Originally Posted by ChuckORWC View Post
One of the reasons I'm considering DCR is to minimize the negative effects of a long, skinny BR chamber.
Why not take advantage of that? There is an ML-TL that works with 2 W14. We used a pair in a 10 L vented enclosure with FF85wKeN as mid-tweeter, they worked well in that volume althou don't get the extention they do in the ML-TL.

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 29th June 2015, 09:12 PM   #6
planet10 is offline planet10  Canada
frugal-phile(tm)
diyAudio Moderator
 
planet10's Avatar
 
Join Date: Oct 2001
Location: Victoria, BC, NA, Sol III
Help me design a mini-tower TMM DCR speaker...
Quote:
Originally Posted by ChuckORWC View Post
[*] My understanding is that paralleling two drivers halves the impedance and increases the sensitivity by some factor. I presume that changes when going 2.5-way. Would it be preferable to use the 4-ohm version of these drivers if I were to go with 2.5-way?
For a 2.5 way you would want to use the 8 ohm drivers and have a 4 ohm capable amp.

Quote:
[*] Would modifying both of the woofers (in 2-way) or just the mid-woofer (2.5-way) with phase plugs help to improve the upper range of the woofers and permit a higher crossover point?
Probably not.

Quote:
[*] Iím planning on using 3/4Ē MDF.
I'd recommend good quality plywood. MDFs primary asset is that it is cheap.

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

Reply


Help me design a mini-tower TMM DCR speaker...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

Forum Jump

Similar Threads
Thread Thread Starter Forum Replies Last Post
MARTELLO-2, a mini-tower from a single 2' x 4' Bigun Full Range 62 25th September 2018 09:18 PM
2-way mini tower Byronkoeder Multi-Way 25 25th March 2014 03:37 AM
3.5 Way Tower speaker design on £250 budget running123 Multi-Way 26 1st August 2013 04:31 PM
Thinking about building a tower speaker from this design pfar Multi-Way 1 11th January 2010 09:07 PM
Micro Mini Desktop Tower Plans roadsterdriver Full Range 24 18th September 2009 06:42 PM


New To Site? Need Help?

All times are GMT. The time now is 03:17 AM.


Search Engine Optimisation provided by DragonByte SEO (Pro) - vBulletin Mods & Addons Copyright © 2019 DragonByte Technologies Ltd.
Resources saved on this page: MySQL 14.29%
vBulletin Optimisation provided by vB Optimise (Pro) - vBulletin Mods & Addons Copyright © 2019 DragonByte Technologies Ltd.
Copyright ©1999-2019 diyAudio
Wiki