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 26th June 2007, 01:25 PM   #1
diyAudio Member
 
Join Date: Jun 2007
Default Down firing vs side firing?

What are the advantages/disadvantages of a downfiring sub vs a side firing sub? Would it matter if the port fired down into the floor? Just trying to find some middle ground for HT and music use. I have a JBL PB12...trashed the amp...just wondering!
__________________
Tony
  Reply With Quote
Old 26th June 2007, 01:46 PM   #2
Did it Himself
diyAudio Member
 
richie00boy's Avatar
 
Join Date: Nov 2003
Location: Gloucestershire, England, UK
I would always go downfiring unless the driver suspension is such that the cone sags too much. Downfiring is more stable, more of an issue with monster subs though really.
__________________
www.readresearch.co.uk my website for UK diy audio people - designs, PCBs, kits and more.
  Reply With Quote
Old 26th June 2007, 03:59 PM   #3
diyAudio Member
 
Sonusthree's Avatar
 
Join Date: Dec 2005
Location: Sussex, UK
I'm building downfiring subs at the moment as a way to keep them safe from kids and clumsy adults!
  Reply With Quote
Old 26th June 2007, 09:44 PM   #4
Marsh is offline Marsh  United Kingdom
diyAudio Member
 
Join Date: Mar 2007
I have a DF sub but It sounds better on its side firing into the room, go figure????????????
__________________
I learn something old every day.
  Reply With Quote
Old 26th June 2007, 10:15 PM   #5
pjpoes is offline pjpoes  United States
diyAudio Member
 
Join Date: Jan 2005
Location: New York
Send a message via AIM to pjpoes
I don't see how a downfiring sub is more stable, can you please explain what you mean?

I have read that manufactured downfiring subs have the suspension biased to account for the potential sag, but I really don't think thats much of an issue. I would say, if the sub is working from 60-80hz and lower, having it downfire shouldn't affect sound any, as long as it had a clear path underneath it. You don't want to burry your driver in deep pile carpet. The advantages of such a setup are that its protected from hands, it transmits vibrations more effectivly to the floor, and if the floor is carpeted, it will absorb higher frequency sounds from the driver, making it harder to detect its location.

The downsides are that a lot of people feel it sounds worse. Again, I can only see this being so in the higher bass frequencies, but its possible that higher harmonics still produced by the sub play a roll in our perception of bass instruments, and that the downfiring position absorbs those. It's also possible that it effects the FR, but again, I've never seen anything to really suggest that.

I don't happen to like downfiring subs myself, but its a subjective reason. I couldn't give you a good technical reason why. My last subwoofer design was downfiring, my current one faces forward. So many variables changed between those two designs, that I don't know what caused what, but I like the new one better. It has much better upper sub-bass sound. I did try firing it toward the floor by supprting its front on wood blocks, and I didn't like the sound as much, so thats the best A/B test I ever did, keeping everything equal, but again, I have no techincal explenation for the differences I heard.
  Reply With Quote
Old 26th June 2007, 10:33 PM   #6
troystg is offline troystg  United States
diyAudio Member
 
troystg's Avatar
 
Join Date: Apr 2004
Location: In a dream... Please don't wake me.
Default Re: Down firing vs side firing?

Quote:
Originally posted by Tee-Bruce
What are the advantages/disadvantages of a down firing sub vs a side firing sub? Would it matter if the port fired down into the floor? Just trying to find some middle ground for HT and music use. I have a JBL PB12...trashed the amp...just wondering!

Down firing is "acoustically loaded" more efficiently than a side firing woofer. By that I mean a down firing woofer will have a better transfer of energy from the mechanical device to the acoustic pressure wave.

The DF woofer will displace x amount of air under the enclosure which in turn will push more air on the sides of the enclosure. Similar to a horn loaded design.

A "free firing" woofer is trying to pressurize the entire room immediately verses the confined space beneath the enclosure.

Same woofer in optimal SF and DF boxes, the DF will give more pressure. Might not sound as good, but should generate more pressure.

I use front or side firing but that is preference. I'm about to make a dual 8 DF for under a couch..

BTW, I'm in Lafayette.
__________________
Troy
Thinking positive doesn't make things better, it makes you a better person.
  Reply With Quote
Old 26th June 2007, 10:58 PM   #7
diyAudio Member
 
Join Date: Jun 2007
Where should I place the port of this cabinet...If I have the port down firng, the legs of this cabinet would have the port about 2" from the floor. Also it would be on a wood floor. I also agree that some upper low-end freqs would be lost when the sub is DF.
__________________
Tony
  Reply With Quote
Old 27th June 2007, 02:06 AM   #8
troystg is offline troystg  United States
diyAudio Member
 
troystg's Avatar
 
Join Date: Apr 2004
Location: In a dream... Please don't wake me.
You would have to factor in the confined space between the enclosure and the floor into your port calculations. It would NOT be the same as a front or rear port.
__________________
Troy
Thinking positive doesn't make things better, it makes you a better person.
  Reply With Quote
Old 27th June 2007, 02:37 AM   #9
KP11520 is offline KP11520  United States
diyAudio Member
 
KP11520's Avatar
 
Join Date: Apr 2007
One advantage that I can see for the DF is it can be anywhere on the floor it needs to be, to fill up the room with bass, even in the middle of the room. Now whether that outweighs all the other downsides is something that may have many different opinions.

Regards//Keith
__________________
If Wile E. Coyote had enough money to buy all that ACME ****, why didn't he just buy dinner?
  Reply With Quote
Old 27th June 2007, 02:38 AM   #10
diyAudio Member
 
Join Date: Jan 2005
Location: Penticton
I've had both DF and SF subs, and I prefer SF. The reason is that I just cannot get my head around the fact that I feel that downward firing subwoofers must surely have to contend with some kind of back-pressure, call it 'pressure echo' (my new phrase of the week), coming back at the cone from the floor.

My feeling is that that this 'echo' would mess with the cone's intended travel as it attempts to reproduce further notes to some [small] extent, thus inducing distortion.

Has anyone here ever read of any tests / evaluations of said ‘back-pressure theory’?

Andrew D.
www.cdnav.com
  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
side firing sub chainenoble Subwoofers 2 23rd October 2006 06:35 PM
Woofer: side firing pair vs front firing? tcpip Multi-Way 13 9th September 2005 02:13 PM
side firing sub chainenoble Subwoofers 2 29th August 2005 03:29 AM
Side firing woofers in 3-way Mos Fetish Multi-Way 7 3rd August 2003 01:57 PM
side firing woofers ogp Multi-Way 2 9th January 2002 01:44 AM


New To Site? Need Help?

All times are GMT. The time now is 10:40 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