Notices
Audio & Video 350Z Mobile entertainment and other electronics

sub experts, need your inputs....

Thread Tools
 
Search this Thread
 
Old 12-20-2003, 02:18 PM
  #1  
Z8M
Registered User
Thread Starter
iTrader: (3)
 
Z8M's Avatar
 
Join Date: Aug 2003
Location: Cali South
Posts: 330
Likes: 0
Received 0 Likes on 0 Posts
Default sub experts, need your inputs....

I've seen some enclosures where the sub is inverted, you know when the butt end is sticking out of the box. What advantage does this design has over the traditional "butt end" inside the box. How is the sound quality of the bass? Does the minimum cu.ft. of air space required by each subwoofer still applies? Thanks
Old 12-20-2003, 02:24 PM
  #2  
bastard
Registered User
 
bastard's Avatar
 
Join Date: Aug 2002
Location: California
Posts: 298
Likes: 0
Received 0 Likes on 0 Posts
Default

The point of an inverted sub is mostly to show off the sub more--it's usually only done for subs that have nice looking baskets and magnets. The airspace requirement should be the same. I would think the bass wouldn't have as much loudness potential due to the loss of cone area. Obviously, this installation will use more space inside the car.
Old 12-20-2003, 07:53 PM
  #3  
Dream2Reality
Registered User
iTrader: (1)
 
Dream2Reality's Avatar
 
Join Date: Feb 2003
Location: New Jersey
Posts: 240
Likes: 0
Received 0 Likes on 0 Posts
Default

Originally posted by bastard
I would think the bass wouldn't have as much loudness potential due to the loss of cone area.
The difference is inaudible. I've done it when I had a prefab box that wasn't deep enough for my subwoofer, so I flipped it around; works fine. Just make sure the hole is the right size, otherwise the surround will rip.
Old 12-26-2003, 09:54 PM
  #4  
GSteg
Registered User
 
GSteg's Avatar
 
Join Date: Dec 2003
Location: westminster, ca
Posts: 2
Likes: 0
Received 0 Likes on 0 Posts
Default

cone area is still there so you have really nothing to lose.
Old 12-28-2003, 08:12 AM
  #5  
350G
Registered User
iTrader: (4)
 
350G's Avatar
 
Join Date: Aug 2003
Location: Lexington, KY
Posts: 811
Likes: 0
Received 0 Likes on 0 Posts
Default

Besides the middle area of the cone, you still displace almost the same amount of air. The only real advantage with inverted is that you present it with a larger enclosure since the sub doesn't displace air within the enclosure. It also looks good provided the sub has a massive magnet and some nice binding posts.

Plus, its relatively easy to test the speaker's ohm to determine if you fried a voice coil
Old 12-28-2003, 11:01 AM
  #6  
JimRHIT
Registered User
iTrader: (6)
 
JimRHIT's Avatar
 
Join Date: Mar 2003
Location: Hermosa Beach, CA
Posts: 4,416
Likes: 0
Received 0 Likes on 0 Posts
Default

It allows you to make a smaller box for a given box design.

Since the basket and motor structure will no longer be "in" the box and taking up volume, the box is "bigger" so to speak. Also, the inversion of the cone makes for even more effective box volume.

Most people do it for show.... not all though. In my friend's FireHawk, it was our only option to get the box volume we needed as well as keeping his T-Top storage, even though the baskets on his JL W3s were ugly, it sure ended up sounding great.

Jim
Old 06-30-2006, 01:33 PM
  #7  
VO...
Administrator
iTrader: (25)
 
VO...'s Avatar
 
Join Date: Jun 2005
Location: Down Under & Dirty
Posts: 58,609
Received 2,747 Likes on 1,836 Posts
Default

I thought I'd bring this thread back from the dead, after finding it on a search....
I have pretty much the same question as the orginator of the thread, with a slight variation. Does it matter whether the enclosure is ported or sealed, when mounting the sub inverted? I've got a Fosgate T112D4 that has a pretty nice looking magnet and I'd like to display it better. The enclosure is in the spare tire well and displaces 1.25 cuft. It's a sealed enclosure. I do not wish to lose any sound quality. Can anyone offer any input?
Old 06-30-2006, 02:09 PM
  #8  
perrogrande007
Registered User
iTrader: (4)
 
perrogrande007's Avatar
 
Join Date: Jun 2006
Location: Austin, TX
Posts: 150
Likes: 0
Received 0 Likes on 0 Posts
Default

From what I hear you will lose about 3 dbs by inverting the sub. I have done this with various speakers and they always sound like there is less output, especially in a sealed box.

However, the SQ will sound the same IMO
Old 07-01-2006, 08:37 AM
  #9  
Fluid1
Registered User
iTrader: (19)
 
Fluid1's Avatar
 
Join Date: May 2005
Location: NOPE NOPE NOPE
Posts: 11,953
Likes: 0
Received 0 Likes on 0 Posts
Default

If you have quality equipment that requires a sealed subwoofer box, do NOT invert the sub.
If you have a ported box and a SPL only sub and are not competing I guess it's okay. This is only done for show or when space is an issue somehow.
Old 07-01-2006, 09:17 AM
  #10  
JimRHIT
Registered User
iTrader: (6)
 
JimRHIT's Avatar
 
Join Date: Mar 2003
Location: Hermosa Beach, CA
Posts: 4,416
Likes: 0
Received 0 Likes on 0 Posts
Default

You will not lose 3dBs of output, that is complete BS.

There is no audible degradation in SQ by inverting it ... I have no idea where Fluid1 got that from. The only audible differences are that the pole vent (the hole in the magnet area) could make some audible chuffing at high volumes. The cone area difference is very small.

Look at it this way. You have a 9.25" wide effective cone area on a sub.

Pi*(9.25/2)^2 vs Pi*(2.5/2)^2 .... so thats about a ~15% cone area loss ...
then consider that you need to add an ENTIRE second 10" sub to gain 3 dB ... you surely aren't gonna lose 3 dB by losing 15% piston area.

Food for thought,
Jim
Old 07-03-2006, 07:04 AM
  #11  
VO...
Administrator
iTrader: (25)
 
VO...'s Avatar
 
Join Date: Jun 2005
Location: Down Under & Dirty
Posts: 58,609
Received 2,747 Likes on 1,836 Posts
Default

Originally Posted by JimRHIT
The only audible differences are that the pole vent (the hole in the magnet area) could make some audible chuffing at high volumes.
I tested my system out this weekend while inverting the speaker. You are correct on the chuffing sound. It is audible at high volumes. I'm just going to keep the sub firing in the upward position.
Attached Thumbnails sub experts, need your inputs....-imgp1211.jpg  
Old 07-03-2006, 05:18 PM
  #12  
04silverzcoupe
Registered User
 
04silverzcoupe's Avatar
 
Join Date: Oct 2005
Location: nc
Posts: 197
Likes: 0
Received 0 Likes on 0 Posts
Default

Originally Posted by perrogrande007
From what I hear you will lose about 3 dbs by inverting the sub.
care to explain this....
Old 07-03-2006, 05:23 PM
  #13  
JimRHIT
Registered User
iTrader: (6)
 
JimRHIT's Avatar
 
Join Date: Mar 2003
Location: Hermosa Beach, CA
Posts: 4,416
Likes: 0
Received 0 Likes on 0 Posts
Default

He doesn't need to .. he was just letting us know of what he heard. He may have been incorrect ... but he never really tried to push it on us, so lets not grill him

Either way, the truth has been revealed above
Old 07-03-2006, 05:44 PM
  #14  
Paul350Z
Living in 350Z
iTrader: (1)
 
Paul350Z's Avatar
 
Join Date: Mar 2005
Location: Riverside CA
Posts: 4,704
Likes: 0
Received 2 Likes on 2 Posts
Default

You could mount a second woofer inside to form a trapped volume of air which is sent back and forth using one speaker to push and the other to pull. This sort of set up is call isobaric and is pretty rare (at least I ain't seen one!). The second internal speaker might be a way to "cheat" and get another 3dB worth of power into/out of the same size box.

Another enclosure design that you may hear of is isobaric. Isobaric is not actually an enclosure type but a woofer loading method. Isobaric loading can be used in conjunction with any of the enclosure types, except perhaps infinite baffle. Isobaric loading consists of two woofers coupled together by a short enclosure which is only long enough to prevent the two woofers from striking one another. The woofers may be mounted face to face, back to back or front to back. It is important however to have the woofers firing in phase with one another. In order to accomplish this with the woofers firing front to front or back to back one of the woofers speaker leads must be reversed with respect to the other woofer.

Isobaric loading is usually used when space is at a minimum or a maximum number of woofers wish to be used in a certain volume of space. By isobarically loading the woofers, a box of only half the size of a one woofer box is needed. For example, if a 12" woofer requires a two cubic foot box, the same 12" woofer isobarically loaded only requires a one cubic foot box. The cost of this design, other than doubling the woofer cost, is a reduction in the subwoofer system efficiency by three decibels (if both woofers are given the same power as a single woofer), which is equivalent to halving the amplifier power. New, small box subwoofer designs have all but negated the need for isobaric loading in car audio and it has fallen out of popularity.

Advantages of this design are increased linearity in the speaker movement, lower space requirements, and increased power handling.

Disadvantages are increased cost, increased design and assembly complexity, and decreased efficiency.
There are some disadvantages of inverse mounting of the subwoofer. At lower sound levels you possibly can hear the motor noise and the spider isn't always treated to take the UV rays of the sun like the "top" side components of the speaker.

One of the advantages is that speaker magnet will be that it will be cooler as the woofer can vent to the free air of the car interior.

Here's a pretty good subwoofer forum.
http://www.diysubwoofers.org/
Old 07-05-2006, 12:53 PM
  #15  
VO...
Administrator
iTrader: (25)
 
VO...'s Avatar
 
Join Date: Jun 2005
Location: Down Under & Dirty
Posts: 58,609
Received 2,747 Likes on 1,836 Posts
Default

Originally Posted by Paul350Z
You could mount a second woofer inside to form a trapped volume of air which is sent back and forth using one speaker to push and the other to pull. This sort of set up is call isobaric and is pretty rare (at least I ain't seen one!). The second internal speaker might be a way to "cheat" and get another 3dB worth of power into/out of the same size box.



There are some disadvantages of inverse mounting of the subwoofer. At lower sound levels you possibly can hear the motor noise and the spider isn't always treated to take the UV rays of the sun like the "top" side components of the speaker.

One of the advantages is that speaker magnet will be that it will be cooler as the woofer can vent to the free air of the car interior.

Here's a pretty good subwoofer forum.
http://www.diysubwoofers.org/
It would be nice to try this, except I have not way of dissasembling the box to mount the inner sub. Here's a pic of the enclosure. 1.25 cu ft of internal usable airspace.
Attached Thumbnails sub experts, need your inputs....-imgp1237.jpg   sub experts, need your inputs....-imgp1239.jpg  
Related Topics
Thread
Thread Starter
Forum
Replies
Last Post
Lt_Ballzacki
Brakes & Suspension
39
08-06-2021 06:19 AM
m_0g
Audio, Video & Electronics (DIY)
12
06-03-2021 10:05 AM
carid
Misc.
0
09-10-2015 06:16 AM
Encore
Audio Builds
69
09-29-2008 05:50 PM
Canadian350Z
Exterior & Interior
1
03-01-2003 04:19 PM



Quick Reply: sub experts, need your inputs....



All times are GMT -8. The time now is 03:51 PM.