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528hz
01-19-2008, 09:57 PM
So I have 2 12" in a sealed box and they're facing towards the back of the trunk. I was searching about down firing for more output and thought if you connected a separate piece of at the end of the box (you would have 2 openings at the top and bottom) wood extended about 4"-4.5" off of the box, would this act in the same way as down firing?

BrianChia
01-19-2008, 10:07 PM
No.

528hz
01-19-2008, 10:41 PM
really? It wouldn't have the same effect? Because it's closed off on the ends?

Immacomputer
01-20-2008, 12:14 AM
I'm confused about what you're meaning. Are you talking about a panel sitting in front of the speaker covering it completely but leaving the sides open? If that's what you're saying, you're talking about a loading panel which IS the same idea as down-firing an enclosure.

528hz
01-20-2008, 01:09 PM
A loading panel sounds exactly like what I mean. O.k. picture a regular, rectangular box with the speakers facing you. Now, on the ends I would screw 2 pieces about 6" long and 4" wide to the box. Then attach a separete piece of wood the same size as the face of the box.

Immacomputer
01-20-2008, 01:21 PM
Like this:
http://i30.tinypic.com/1zves8g.png

And yes, it would work just like down firing and it would give the subs something to load off of in front of them. It should increase mechanical power handling and give an extended low end.

528hz
01-20-2008, 01:24 PM
Yes Sir Mr. Computer, that is it. I think I'm going to do this and have always wanted to try it because it makes since and is the same, if not better, than putting it close to the trunk. Thanks a lot!

Immacomputer
01-20-2008, 02:03 PM
Let us know how it goes. Experiment with different distances too!

528hz
01-20-2008, 06:26 PM
Will do. It'll be a week or so.

thegreatestpenn
01-20-2008, 07:49 PM
the output you gain doing that probably isn't as much as the output you'd gain using a ported box so why not just get/make a ported box and tune it to what you like? That or turn the sub around and wall it off from the back of your trunk so its going directly into your car's cabin

528hz
01-20-2008, 08:08 PM
I know its not going to be like a ported box and that's not my intention. I DON'T want a PORTED box because of the late response compared to a SEALED box, and I know how ported boxes are because I've probably had 20 or so in the past years.

IDSkoT
01-20-2008, 08:31 PM
Why not just flip the box facing down and make stands for it...?

thegreatestpenn
01-20-2008, 08:57 PM
I know its not going to be like a ported box and that's not my intention. I DON'T want a PORTED box because of the late response compared to a SEALED box, and I know how ported boxes are because I've probably had 20 or so in the past years.

A well-built ported enclosure will have the same precision as a sealed box. If you tune it to 26-30Hz the response is pretty flat above 40Hz. but to each his own, good luck with your project!

528hz
01-20-2008, 09:37 PM
A well-built ported enclosure will have the same precision as a sealed box.

I don't believe that's true. Since the types of music I listen to (Drum and Bass, breaks, metal, rock) hitting clean, fast repsonses in quickly changing frequencies of bass are not what ported boxes do well no matter how you tune it.

But looking at your sig, how are the baffles different sounding that of a slotted port?

528hz
01-20-2008, 09:39 PM
Why not just flip the box facing down and make stands for it...?

I think the denser surface would be better than reflecting the sound off carpet. The carpet would probably absorb some sound, plus I don't want the box falling over in the trunk.

skadude016
01-20-2008, 09:43 PM
A well-built ported enclosure will have the same precision as a sealed box. If you tune it to 26-30Hz the response is pretty flat above 40Hz. but to each his own, good luck with your project!

x2! for serious you can gain output, and depth in the music going ported

528hz
01-20-2008, 09:49 PM
My main concern is RESPONSE. You can not tell me that a ported box responds with the quickness as a sealed box does. You put music in that has a lot of double kick drums or quickly changing frequencies and tell me the notes don't start to run together in a ported box or worse yet are hundreths of a second off...

Immacomputer
01-20-2008, 10:03 PM
I don't believe that's true. Since the types of music I listen to (Drum and Bass, breaks, metal, rock) hitting clean, fast repsonses in quickly changing frequencies of bass are not what ported boxes do well no matter how you tune it.

But looking at your sig, how are the baffles different sounding that of a slotted port?

It depends on the enclosure volume, sub used, and tuning frequency. I listen to a lot of break beat and a lot of metal with crazy kick drums and my sub's transient response is just as nice as it was sealed. Something you probably don't realize is that above tuning, a ported enclosure acts like a sealed enclosure of the same volume. If you tune low enough, your transient response will be similar or identical to the sealed enclosure. What you're describing is group delay caused by the port in the port's bandwidth. By tuning low, you decrease the port's bandwidth and lower the group delay in the frequency range where music is mostly present and then you will get better transient response with additional output down low.

I have a friend that made all sorts of complaints about ported enclosures being sloppy and horrible with transient response. I let him listen to my setup and he asked me right away to build him a proper ported enclosure for his subs since he was having issues below 40hz.

It's not the enclosure type that dictates how a system will perform but the alignment of the sub and enclosure system.

528hz
01-20-2008, 10:09 PM
Well *****, I am always up for learning more meticulous details in the box design. I'm just like your friend. So, if I tune to 30hz or so, how well is that going do in the 45-60hz range?

I've got 2 12" older MMATS Pro Audios (700 peak watts) and there running, or should I say going to, run off the Sundown 1500D.

Immacomputer
01-20-2008, 10:10 PM
It depends on the enclosure size and subs.

528hz
01-20-2008, 10:19 PM
So would it be safe to say that building a ported box to the MINIMAL specs suggested for a specifc sub and tuning low would be best?

Immacomputer
01-20-2008, 11:22 PM
No, I won't say that not knowing what the subs are.

528hz
01-21-2008, 12:48 AM
There the older MMATS Pro Series (700 watts peak)

P2.5-12

Sealed (Net) Vented (Net) Port Specs Port Disp. Woofer Disp.
Min. 0.70 cu.ft. 1.25 cu.ft. 3”dia. X 9” L .04 cu.ft. .13 cu.ft.
Rec. 0.88 cu.ft. 1.50 cu.ft. 4”dia. X 12” L .09 cu.ft. .13 cu.ft.
Max. 1.15 cu.ft. 1.75 cu.ft. 4”dia. X 10” L .07 cu.ft. .13 cu.ft.

528hz
01-23-2008, 10:38 AM
Immacomputer or anyone else want to help me with this box design. I'm going to go ahead and have a sealed and ported box (2 different boxes) for these 2 12". I'm going to tune low and need some specs for air space and dimensions.