Need good drivers for 'copper' speaker cabinet - diyAudio
Go Back   Home > Forums > Loudspeakers > Multi-Way

Multi-Way Conventional loudspeakers with crossovers

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 20th November 2008, 06:00 AM   #1
diyAudio Member
 
kstlfido's Avatar
 
Join Date: Mar 2006
Location: Berkeley, CA
Default Need good drivers for 'copper' speaker cabinet

Hello fellow diyaudio peeps-

Some of you might recall my copper speaker at Burning Amp. It is one of a pair that I put together for my camp at Burning Man. The speaker cabinets were not assembled by me; I just 'dressed them up' with copper and brass; and added the tripod stands. Cabinets are made on 3/4" MDF.

While on the playa, the drivers blew out. They were fairly cheap University 8" full range units from the 60's (model 308's).

I would like to find a suitable replacement driver; possibly a full range unit that can handle al least 60 watts. I intend to add some form of tweeter assembly above or mid/tweet in the center. It needs to be fairly durable as it will be exposed to the hot desert elements for a week.

I calculated the internal cabinet volume, appx 1.25 cubic feet. There is a port (3in dia. X 3in long) but this can be closed or changed if need be. Driver size can be anything up to ~9".

I realize this is not going to go down too low; I would be lucky to get to 100hz!

I am not much of a speaker designer and there seems to be a wide choice of 8" units.

This is how they appeared on the playa, below. If anyone can help, I would be grateful!

Cheers- Kent
Attached Images
File Type: jpg speakers1-03.jpg (77.3 KB, 2962 views)
  Reply With Quote
Old 20th November 2008, 06:50 AM   #2
diyAudio Member
 
Join Date: Jan 2004
Location: Toronto, ON, Canada
Put some thin subs on the sides in the form of wings and you have yourself a TIE Fighter.
  Reply With Quote
Old 20th November 2008, 11:04 AM   #3
diyAudio Member
 
Join Date: Jun 2006
Send a message via Yahoo to musgofasa
Sounds like a job for the pioneer BOFU to me.

http://www.parts-express.com/pe/show...number=290-045

Lots of other options too. I believe you could seal off the port, maybe do a little tweaking or possibly just add tweeter and have something that sounds pretty good. These drivers have a pretty awesome reputation considering their price.

Good luck
Robert
  Reply With Quote
Old 20th November 2008, 11:10 AM   #4
sreten is offline sreten  United Kingdom
diyAudio Member
 
Join Date: Nov 2003
Location: Brighton UK
Hmmm .......

8" units that are genuine bass / midranges are increasingly rare.

http://www.parts-express.com/pe/show...number=296-175

Looks relatively easy to work with according to PE sample
measurements, i.e. no large or narrowband peaks / dips.

http://www.parts-express.com/pdf/296-175g.pdf

It will get you down to at least 40Hz but genuine freefield as
in your picture is an entirely different matter to use in a normal
sized room.

My experience of Audax drivers is they are very robust and take
abuse. An 8" fullrange by default must have a delicate voice coil.

Its ideal for your box size and IMO a 2" diameter 5" long port.
Thats ~ 33Hz tuning though you can go up to ~ 40Hz.
Lining your port with 1/2" foam is workable, ~ 37Hz.

The tweeter one has to suggest :
http://www.parts-express.com/pe/show...number=297-409
Just because of the packaging.

It needs a proper crossover at > 3kHz, simple will not work
well nor will trying to cross lower, 5th harmonic distortion
has a peak at 1.5Khz you neeed to avoid.

I suggest you read up on Baffle step compensation and
diffraction effects of cabinets if you want a good crossover.

You may be able to get away with a single large inductor
on the bass driver, this will be a lot larger than than a
"textbook" cross over value, due to response tailoring.

http://www.parts-express.com/project...m?project=Sc51

Is worth perusing as an example of how not to go about
crossing over two drivers, off the shelf does not work.

http://www.rjbaudio.com/Audiofiles/FRDtools.html
http://www.geocities.com/woove99/Spk...esigningXO.htm

As a minimum experiment with various series inductors to get
the driver ~ flat and bring in the tweeter at 3KHz, using an
L-pad to set its level. Tweeter c/o 2nd or 3rd order electrical.

/sreten.
  Reply With Quote
Old 20th November 2008, 11:43 AM   #5
infinia is offline infinia  United States
diyAudio Member
 
infinia's Avatar
 
Join Date: May 2005
Location: Californication
Hi
My guess is that sheer SPL and "survival" is more important than bass to this application? If so, then a BSC design is out.
Assuming that then, a 8" pro driver that rolls off quickly to match the tweeters sensitivity would be ideal. But after mulling that over, you might probably want a 1" compression tweeter with a new DIY biggish copper horn?
__________________
like four million tons of hydrogen exploding on the sun
like the whisper of the termites building castles in the dust
  Reply With Quote
Old 20th November 2008, 12:23 PM   #6
sreten is offline sreten  United Kingdom
diyAudio Member
 
Join Date: Nov 2003
Location: Brighton UK
Quote:
Originally posted by infinia

.... If so, then a BSC design is out .....
Hi,

Quality versus quantity (SPL) is always an issue, I go for the first.
Active (line level) BSC is another option if the ampifier chain is fixed.

/sreten.
  Reply With Quote
Old 20th November 2008, 12:45 PM   #7
infinia is offline infinia  United States
diyAudio Member
 
infinia's Avatar
 
Join Date: May 2005
Location: Californication
I go to the application/requirements first. If you can't hear it or if it busts down, then quality doesn't matter in the end really. The same shoe rarely fits all feet.
__________________
like four million tons of hydrogen exploding on the sun
like the whisper of the termites building castles in the dust
  Reply With Quote
Old 20th November 2008, 01:11 PM   #8
sreten is offline sreten  United Kingdom
diyAudio Member
 
Join Date: Nov 2003
Location: Brighton UK
Quote:
Originally posted by infinia
The same shoe rarely fits all feet.
Indeed, that is the point , /sreten.
  Reply With Quote
Old 20th November 2008, 07:54 PM   #9
Pano is offline Pano  United States
diyAudio Moderator
 
Pano's Avatar
 
Join Date: Oct 2004
Location: Milliways
Blog Entries: 4
Those are some great looking "Steampunk" speakers!

I did a pair of copper faced speakers, once. Tall and narrow, the theme was Tiki. My wife did the copper bas-relief with the tweeter in the tiki's mouth, woofer in it's belly. (see my avatar for an idea of her work)

Wish I had taken photos.......

Good look with your project - I hope you find drivers as sturdy as those cool boxes.
__________________
Take the Speaker Voltage Test!
  Reply With Quote
Old 20th November 2008, 09:05 PM   #10
diyAudio Member
 
kstlfido's Avatar
 
Join Date: Mar 2006
Location: Berkeley, CA
Hi Chaps-

Thanks for great ideas & driver selections. Very helpful!

Yes, I can pad the interior. There is some carpet glued to some of the inside panels already. I would like to keep away from paper cones and foam surrounds due to the sun and elements. I like that teardrop tweeter- seen it before. Yes, 'survival' is more important than bass for this project.

Cosmetics- one idea was to use a translucent cone-
http://www.parts-express.com/pe/show...number=290-055
I had an idea to 'light' the interior, this would look cool. Hey, it's Burning Man, fun night-time lighting is big part of the event! But coupling it with the teardrop shape tweeter will leave a big suckout in the 2-3k range...

Hmm....a diy horn? Now you got me thinking! It might get kind of long- I need to do some modeling to figure out sizes.

Yes, the term steampunk has been used before describing these. I prefer the term 'Jules Verne-esque'.
  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
is Warnex textured speaker cabinet paint good? pikcellmix Multi-Way 2 25th November 2010 05:42 PM
Harmony Taiwan speaker drivers - any good? Spasticteapot Multi-Way 0 20th January 2007 10:31 PM
how to make good cabinet for 12" coacial speaker partyjups Multi-Way 1 27th May 2006 01:15 PM
Really good hifi speaker drivers by Audax Bull Multi-Way 0 2nd May 2003 10:08 PM


New To Site? Need Help?

All times are GMT. The time now is 08:53 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