full range in an existing small cabinet - 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 5th September 2012, 10:06 PM   #1
mda1 is offline mda1  Netherlands
diyAudio Member
 
Join Date: Sep 2012
Default full range in an existing small cabinet

Hi all,

This is my first post here after trying to read all the threads that already brought me a bunch of answers (and many new pages to read in the infinite knowledge that one can find on the internet).

My challenge is as follows: I inherited a pair of beautifully designed but quite badly sounding design speakers from the 70's. The enclosures are spherical brushed aluminium with a diameter of about 20cm diameter (8 inches). The driver inside is about 5 inches (133 mm BCD, slightly smaller baffle) and a tiny tweeter in front. Both straight from the 70's and well... sound as such . After a bit of research I have decided that I would like to replace this combination with a single full range driver as I like the simplicity and philosophy of the single driver.

The full range driver has to fit in this existing enclosure, so I am limited to something between 4 and 5 inches. The air volume in the (closed enclosure) is about 1 or 2 liters (depending on the driver one puts in there).

I understand that in these conditions I will not be able to have a very much in the lower freq range... but there is not much I can do about that I think (right?)

I listen all kind of music, but almost no jazz and no classical music.

I driver my speakers with a rotel pre-amp and a NAD 216 amp.

Now the question: which driver should I choose?

I have been doing some research already and ended up on the likes of TangBand and Fostex. How do these compare?

As this is my first build project (well, for speakers at least), I would be happy with any advice I can get.
  Reply With Quote
Old 5th September 2012, 11:21 PM   #2
frugal-phile(tm)
diyAudio Moderator
 
planet10's Avatar
 
Join Date: Oct 2001
Location: Victoria, BC, NA, Sol III
Blog Entries: 5
How thick is the Al? How big a sloce off the end to mount the driver. a 10 cm R sphere os about 4 litres.

When one has 2-2.5 litre to play with i immediately think of Fostex FF85wk. If it is at the large end of that volume, A6.2m or A6.2p are candidates.

Can you post pictures?

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 6th September 2012, 12:15 AM   #3
mda1 is offline mda1  Netherlands
diyAudio Member
 
Join Date: Sep 2012
thanks for you reply. I'll get some pictures tomorrow.
The slice that comes off the sphere is about 1/2 to 1 liter so I don't lose too much there. Then comes the volume of the driver itself. So I am indeed left with something like 2-2.5 liters depending on the driver chosen.

This FF85WK you recommend is smaller than what I could mount in there. What is the reason that you recommend this one in particular? (note: i don't doubt your choice, I just want to learn...)
  Reply With Quote
Old 6th September 2012, 12:29 AM   #4
frugal-phile(tm)
diyAudio Moderator
 
planet10's Avatar
 
Join Date: Oct 2001
Location: Victoria, BC, NA, Sol III
Blog Entries: 5
Every driver requires a certain volume to work its best, with the given volume those 3 drivers are what i know works. A larger driver would need greater volume, there are quite a few 5" that can work in 4.5-4.7 litre, but that is as small as i'd put them in.

The 3 mentioned drivers, althou somewhat bass limited are no slouches in the range they do work in.

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 6th September 2012, 02:33 AM   #5
diyAudio Member
 
Join Date: Oct 2005
If you can neatly attach a round plate to the hole in the speaker then in the middle of the plate you can put the FF85WK. Or put it excentric with room for a bass reflex opening below it.
This driver has qualities, but it is not a bass monster. You may want to add a subwoofer to it for complete music enjoyment, possibly also filtering the FF85WK to protect it from the lower frequencies so it can focus on what it does best. To my own taste, a speaker with the FF85WK will not have enough bass on its own.

If you prefer to keep it with 1 driver without sub, then a 3" Tangband is probably a better choice. Since these speakers offer lower efficiency, they can go lower in bass - at the expense of loudness.
  Reply With Quote
Old 6th September 2012, 02:40 AM   #6
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 talaerts View Post
If you prefer to keep it with 1 driver without sub, then a 3" Tangband is probably a better choice. Since these speakers offer lower efficiency, they can go lower in bass - at the expense of loudness.
Same with Alpair 6.2s. Also the Fountek FR88ex

FF85wk with helper woofers are pretty amazing.

Click the image to open in full size.

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 6th September 2012, 09:20 AM   #7
mda1 is offline mda1  Netherlands
diyAudio Member
 
Join Date: Sep 2012
Thanks again for all the answers and advice

The aluminium is 2mm thick. Here are some images of the spheres in original state and after partial disassembly:

Click the image to open in full size.
Click the image to open in full size.
Click the image to open in full size.
Click the image to open in full size.

(the last one is just to show the part that is 'sliced off')

I was not really planning on adding a filter. It adds more complexity to my first project, and because placing the filter inside these spheres will 1) take away even more volume, and 2) be a real challenge to mount / fix in a proper way. Additionally: isn't the beauty of full range that you don't need filters?

As the original way these were made is just a sealed volume, I was planning on doing the same, so I had not thought of a BR design... would you indeed recommend this?
With these speaker I would rather consider adding a subwoofer than pushing the lows on the spheres themselves. And I value a clean sound over volume for this project.
  Reply With Quote
Old 7th September 2012, 08:01 AM   #8
mda1 is offline mda1  Netherlands
diyAudio Member
 
Join Date: Sep 2012
No comments on the sealed vs BR choice?
  Reply With Quote
Old 7th September 2012, 12:51 PM   #9
GM is offline GM  United States
diyAudio Member
 
GM's Avatar
 
Join Date: Jun 2003
Location: Chamblee, Ga.
It would really depend on the sealed system's Q [sysQ]. In such a small cab though, a damped vented alignment [semi-aperiodic] is often the best overall compromise.

An easy test for vented is to gap [space] the driver to create a leaky seal with the greater the gap, the higher it begins rolling off in the bass.

Adding foam or similar in the gap can also change its tone, creating an increasingly aperiodic alignment with increasing density, so worth experimenting with also.

GM
__________________
Loud is Beautiful if it's Clean! As always though, the usual disclaimers apply to this post's contents.
  Reply With Quote
Old 7th September 2012, 01:49 PM   #10
mda1 is offline mda1  Netherlands
diyAudio Member
 
Join Date: Sep 2012
Sounds cool... Can you give me a ballpark idea of how 'leaky' my seal has to be? i.e. how much of a gap I should leave between the driver and the board it will be mounted on (there are no drivers with the exact mounting pattern of the old drivers, so for sure I will have to do some woodwork...).

Is it mm's? or rather cm's? (assuming I will use a 3 inch driver).
  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
Spherical Cabinet vs. ordinary Cuboid Cabinet for full range Speakers tiefbassuebertr Full Range 1 10th January 2012 04:49 PM
Easiest cabinet design for full range driver terpkev Construction Tips 23 31st July 2011 08:16 PM
Novice questions re: 1st DIY full range project - existing cabinets rbclark Full Range 23 24th August 2007 01:59 AM
Full range and/or High Efficiency possible in small cabinet? Seraph Full Range 29 19th June 2007 01:13 AM
Help selecting a small Full Range mimir Full Range 9 31st August 2005 05:41 AM


New To Site? Need Help?

All times are GMT. The time now is 07:16 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