Go Back   Home > Forums > Loudspeakers > Subwoofers

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 27th June 2009, 08:56 AM   #1
AllenB is offline AllenB  Australia
diyAudio Member
 
Join Date: Oct 2008
Default What's the best enclosure for this driver?

I want to use a SS 18W8545k as a sub and it doesn't move enough air in a closed box. I like the sound of high efficiency boxes but I'm not looking for a full sized horn and I want f3 lower than 35Hz.

I've been duelling with hornresp for a couple of hours trying to get a useable response in a tapped horn but I can't find one, maybe it's just me or maybe this driver is no good and nothing I do will get it working in a tapped horn?? Should I keep trying with the tapped horn or try another enclosure?
Attached Files
File Type: pdf 18w8545k.pdf (8.3 KB, 46 views)
  Reply With Quote
Old 27th June 2009, 10:20 AM   #2
AndrewT is online now AndrewT  Scotland
diyAudio Member
 
Join Date: Jul 2004
Location: Scottish Borders
a ported box should suit this lowish Q driver with a very low Fs for a 7inch. It even has reasonable sensitivity.
__________________
regards Andrew T.
  Reply With Quote
Old 27th June 2009, 10:51 AM   #3
diyAudio Member
 
rcavictim's Avatar
 
Join Date: Jun 2004
Location: Next to an open wormhole NW of Toronto
7" driver...SUBwoofer????? Yeah right. If it says subwoofer on the factory carton, that is just advertising spin.
__________________
On April 01,2012, my radioastronomy Project TARGET SETI search succeeded. The signal came via extradimensional subspace, not radio waves. I now get a lot of 'visitors'. I took my avatar pic of one friend watching me in my work yard from just 20 ft. away.
  Reply With Quote
Old 27th June 2009, 11:27 AM   #4
diyAudio Member
 
Join Date: Sep 2008
The low FS does make things hard. This is what I got with a little fiddling.
It bottoms out at around 100dB 2pi in 36L.
I'm sure someone could do better but it was a quick one.
Attached Files
File Type: pdf 18w8545k_th.pdf (16.8 KB, 36 views)
  Reply With Quote
Old 27th June 2009, 02:45 PM   #5
GM is offline GM  United States
diyAudio Member
 
GM's Avatar
 
Join Date: Jun 2003
Location: Chamblee, Ga.
Default Re: What's the best enclosure for this driver?

Quote:
Originally posted by AllenB
I want to use a SS 18W8545k as a sub and it doesn't move enough air in a closed box. I like the sound of high efficiency boxes but I'm not looking for a full sized horn and I want f3 lower than 35Hz.
It sims fine once properly damped, but to get a <35 Hz F3 means a fairly big box to get a so-so efficiency in a conic expansion and a ~80% larger box to get a bit more with an expo expansion and 'full size' to make it 'sing', so how big is too big?

GM
__________________
Loud is Beautiful if it's Clean! As always though, the usual disclaimers apply to this post's contents.
  Reply With Quote
Old 27th June 2009, 03:02 PM   #6
bjorno is offline bjorno  Sweden
diyAudio Member
 
Join Date: Mar 2005
Location: Jacobsmountain
Send a message via MSN to bjorno
Hi
As a counter weight to David's IMO well done TH design a T-TQWT is presented here: See picture 1(2).

The T-TQWT has lower FR cut-off and uses less volume /length and is IMO far easier to damp and filter for good SQ above and below 80 Hz.

If equalized to flat pass band the TH will only gain 2.3 dB compared to the T-TQWT: See picture 2(2).

b

1(1)
Attached Images
File Type: gif ss-18w8545k-t-tqwt.gif (88.8 KB, 280 views)
  Reply With Quote
Old 27th June 2009, 03:03 PM   #7
bjorno is offline bjorno  Sweden
diyAudio Member
 
Join Date: Mar 2005
Location: Jacobsmountain
Send a message via MSN to bjorno
2(2)
Attached Images
File Type: gif ss-18w8545k-t-tqwt-vers.th.gif (45.9 KB, 259 views)
  Reply With Quote
Old 27th June 2009, 10:06 PM   #8
AllenB is offline AllenB  Australia
diyAudio Member
 
Join Date: Oct 2008
AndrewT, I might have done that if I couldn't get a tapped horn to work, but thanks.

rcavictim, it's doesn't say sub on the box. Maybe I shouldn't have called it that but I want to cross over below 100Hz.

David_Web and bjorno, so it can be done. I can now see I was looking at it the wrong way but now the TH is back on

GM, I suppose I could stretch a few cubic feet or so if it was worth it. What did you have in mind?
  Reply With Quote
Old 27th June 2009, 11:11 PM   #9
GM is offline GM  United States
diyAudio Member
 
GM's Avatar
 
Join Date: Jun 2003
Location: Chamblee, Ga.
Nothing special, just a bit larger TH to get what I consider an adequate amount of dynamic headroom with a little lower cutoff and <35 Hz F3. Like all THs, damping is required for flattest response over the widest BW:

GM
Attached Images
File Type: gif ss 18w8545k 19.8-186.67 hz conic th - specs.gif (15.7 KB, 236 views)
__________________
Loud is Beautiful if it's Clean! As always though, the usual disclaimers apply to this post's contents.
  Reply With Quote
Old 28th June 2009, 12:44 AM   #10
diyAudio Member
 
rcavictim's Avatar
 
Join Date: Jun 2004
Location: Next to an open wormhole NW of Toronto
Quote:
Originally posted by AllenB

rcavictim, it's doesn't say sub on the box. Maybe I shouldn't have called it that but I want to cross over below 100Hz.


IMO sub-bass only occurs in the first octave (20-40Hz) and a bit below. From 40 Hz up is the realm of a regular woofer. Others might argue that the range described by sub-bass is actually the region below hearing which many texts believe to be 20 Hz.

It is pretty much impossible to move enough air much below 40 Hz to be usefully audible with a tiny driver only measuring 7" frame size. The piston is what maybe 5" diameter to the middle of the surround? It is absolutely impossible to move enough air to be heard at 20 Hz with such a small driver.

Low frequency loudspeakers have to be large. You can make up for lost diameter with increasing excursion up to a point but early on along this path you start seeing the rise of harmonic distortion and 'chuffing' sounds, neither which are related to high fidelity.

The concept of hi-fi seems to have been lost by the modern music and sound reproduction industry. My proof is the popularity of MP3 files and equipment that uses only that highly compressed format being the most encountered. Companies that market home theater in a box will sell you a 1000 watt!!! (more like 1000 milliwatts) system that has six tiny speaker boxes and runs on a wall wart. People have been told through marketing so long that is is the hot sh*t that they believe it. It is all you can find in the stores where the majority of well programmed , dutifull consumer sheeple shop. The companies can sell underperforming crap and laugh all the way to the bank. The only thing that matters any more is the shareholders and the fat CEO salary and bonuses. Customer satisfaction? If you aren't satisfied with our product, you must be using it wrong.

Please do not think I was picking on you at all Allen. It is just that with what you just read all bottled up inside me, when I read 7" and subwoofer in the same sentence it kinda' hit a nerve.

Why are the rest of you here who really do know better leading Allen on?

Allen, you want low bass, sub-bass? Be prepared to buy some large drivers and make a lot of sawdust.
__________________
On April 01,2012, my radioastronomy Project TARGET SETI search succeeded. The signal came via extradimensional subspace, not radio waves. I now get a lot of 'visitors'. I took my avatar pic of one friend watching me in my work yard from just 20 ft. away.
  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
Enclosure for high Q driver lndm Multi-Way 44 16th April 2008 10:41 AM
Have enclosure, need driver diydave Subwoofers 0 11th April 2008 02:49 AM
have enclosure, need driver recommendations talis Subwoofers 6 2nd January 2007 03:08 AM
Sealed Enclosure Driver Madmike2 Subwoofers 2 19th May 2005 12:53 AM
box enclosure for mystery driver timsch75 Car Audio 0 22nd January 2004 05:19 PM


New To Site? Need Help?

All times are GMT. The time now is 11:40 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