Speaker idea: best of both worlds - 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 29th November 2002, 12:55 PM   #1
Nielsio is offline Nielsio  Netherlands
diyAudio Member
 
Nielsio's Avatar
 
Join Date: Nov 2002
Location: The Netherlands
Default Speaker idea: best of both worlds

One world is high efficiency / broadband and the other is conventional moreway.

The speaker I thought up uses:
-A broadband whizzer-less 5" 88 db driver, open baffle [Fostex FX120]
-An 8" 88 db mid-bass driver, sealed [Scan-speak 8545]
-1st order cross-over at 300 hz

The FX120 has a very flat response, which is hard to find in broadband world. Yes, it is only 88 db, but flat frequency respons
is a must, in my opinion.

Sealed enclosure because a ported design (especially in small rooms) will give too much bass.

This way cost and enclosure complexity are kept pretty low, but will have a great (I think) and balanced sound.

My questions are:
-Any comments on this design?
-Does anyone know how I can calculate the needed sealed enclosure volume?
  Reply With Quote
Old 29th November 2002, 02:50 PM   #2
halojoy is offline halojoy  Sweden
On Hiatus
 
Join Date: Nov 2002
Default I like it.

I have a slight feeling, that planet10 will
comment on the Fostex.
It has fs 70 Hz, so 300 is more than 4 times above.

ScanS 8545 is not at all bad suited for sealed box.
So for a reasonable small box, say 50-80 liters
you will get a rather low Fc and f-3dB
And not too high Qtc. I like below 0.7

I would prefer this setup to
8" + 25mm dometweeter.
I would rather have some slope in the upper, beyond my hearing area,
than to let the 8 inch woofer handle
the diskant/treble up to 2500-3000 Hz.

With a power of 16 watts, the Fostex will put out
up to 100dB. It is rated something like 30 W.
It is enough for an ordinary room.
  Reply With Quote
Old 29th November 2002, 06:37 PM   #3
Nielsio is offline Nielsio  Netherlands
diyAudio Member
 
Nielsio's Avatar
 
Join Date: Nov 2002
Location: The Netherlands
That's the idea:
-Not having a crossover in the sensitive area, but still
-Being able to play loud

(hence the Xmax-es of Fostex & Scan-speak: 2 vs 10 mm!)
  Reply With Quote
Old 29th November 2002, 07:11 PM   #4
diyAudio Member
 
apassgear's Avatar
 
Join Date: Nov 2002
Location: Viña del Mar, Torreon
According to to the plot seen at www.eifl.co.jp the Fostex FX120 dosen't look very smooth and off axis roll off is quite steep.

Though it's more expensive the FX200 is much smoother, in this case it seems that a notch filter will be needed at around 4Khz. But as usual it has to be tested.

I am also looking to do something simillar to your project. It would be interesting for you to have look at other threads on the subject since there are almost identical projects been worked.
  Reply With Quote
Old 29th November 2002, 07:33 PM   #5
Nielsio is offline Nielsio  Netherlands
diyAudio Member
 
Nielsio's Avatar
 
Join Date: Nov 2002
Location: The Netherlands
Can you direct me to such projects? I haven't run in to any.

The FX200 is quite more expensive (here in Europe: 145 <-> 215). Strange thing that Fostex measures differently than Eifl. I really want to keep the costs low so that the design can be built by other people too. Also the FX120's efficiency is a better match with the Scan-speak.
  Reply With Quote
Old 29th November 2002, 07:49 PM   #6
halojoy is offline halojoy  Sweden
On Hiatus
 
Join Date: Nov 2002
I also noticed the difference in test curves.
A 5 inch should normally have better off axis responses
than a 8 inch.
  Reply With Quote
Old 29th November 2002, 08:16 PM   #7
frugal-phile(tm)
diyAudio Moderator
 
planet10's Avatar
 
Join Date: Oct 2001
Location: Victoria, BC, NA, Sol III
Blog Entries: 5
What you are describing is one implementation of what i call a "mostly full-range system. I have veen doing it with ESLs for years, but am now playing with conventional drivers (so i can get efficient enuff to also play with small tube amps and Class A SS).

The XO of 300 Hz is as high as you want to go -- lower would be better. Much lower and you have to go active.

As more & more interesting FRs hit the market the choices increase. There are any number of suitable candidates for top end on this kind of thing. This concept will be played out in The Tale of Two Tangbands and the
New Reference Speakers with Full/Wide-Range Driver thread is also covering similar territory. Variacs variation on the Basszilla is the same kind of thing.

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 30th November 2002, 12:56 AM   #8
Nielsio is offline Nielsio  Netherlands
diyAudio Member
 
Nielsio's Avatar
 
Join Date: Nov 2002
Location: The Netherlands
Can anyone comment on:
'Does anyone know how I can calculate the needed sealed enclosure volume?'

Thanks
  Reply With Quote
Old 30th November 2002, 12:58 AM   #9
Nielsio is offline Nielsio  Netherlands
diyAudio Member
 
Nielsio's Avatar
 
Join Date: Nov 2002
Location: The Netherlands
Quote:
Originally posted by planet10
The XO of 300 Hz is as high as you want to go -- lower would be better.
Why?

Quote:
Much lower and you have to go active.
Why??
  Reply With Quote
Old 30th November 2002, 03:31 AM   #10
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 Nielsio
'Does anyone know how I can calculate the needed sealed enclosure volume?'
I just throw the T/S parameters in a box modeling program and then juggle Q and box size until i get something suitable for the application (bigger box means lower Q). My program gives between 6 litres (Q=0.7) to 35 litres (Q=0.5).

kelticwizard has this all stored in his head

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


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
7.1 digital speaker idea GestaltH Digital Source 2 3rd January 2011 12:54 AM
speaker grill idea gychang Full Range 3 31st October 2008 11:32 PM
Crazy speaker idea crick Full Range 0 22nd August 2007 01:03 AM
PC Speaker System (2.1) Idea Help AIA Multi-Way 4 15th October 2006 03:22 AM
portable speaker idea : comments? quiet Multi-Way 1 16th July 2005 03:52 AM


New To Site? Need Help?

All times are GMT. The time now is 12:34 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