Look My Design Over! For my friends Mustang. 2 12" JL's

[SicAudio 5,000+ posts]

Porting tips:

Keep the port(s) as far away from the enclosure sides and back as possible except for the slot type port.

Make sure the inside end of a tube or square port is at least the equivalent of one vent diameter away from the back of the box or any bracing materials.

Keep the vent free from anything that may affect air flow through it.

The port should also be placed as far away from the speaker cone as practical.

and this came from "The Cookbook"

Fb - is the tuning frequency of your enclosure in Hertz.

Lv - is the length of your port in inches.

R - is the inside radius of your vent tube.

Vb - is the internal volume of your enclosure in cubic inches. To convert cubic feet to cubic inches, multiply by 1728.

If you want to use multiple ports, divide your enclosure volume by the number of ports you want to use, then use the result of this calculation as your Vb in the formula below to find out how long each port should be .

If you want to calculate square vents, the formula below will give you the value of R to use in the formula above.

In the formula above, a is the area of your square vent (height x width), and (Pi) is approximately 3.141592.

 

[RAM_Designs 5,000+ posts]

That's referring to a single port approaching the back wall, which is normally going to be in the corner of the box. Just like if you were to use a single L port, you need it to be the same width throughout the port. So if using a straight port going towards the corner of your box, you don't want it closer than the port width, which makes perfect sense. The example you just tried to use has nothing to do with using a T style port that splits in two at the back of the box.

No matter how hard you try you're not going to be right about this.

 

[Try2makeitwork 10+ year member]

Ive always read that the port has to maintain the same port area for the length required, anything else would be another type of design, snail-shell or something like that. Im really excited to get those subs in. Its a 4 channel, I cant remember the brand.

If I ran them series, bridged, i would be at 4 ohm....

 

[Phoenix Risen 10+ year member]

//content.invisioncic.com/y282845/emoticons/popcorn.gif.32dd9e22fd77e77bc3c907062768fcd2.gif

 

[Try2makeitwork 10+ year member]

Porting tips:
Keep the port(s) as far away from the enclosure sides and back as possible except for the slot type port.

Make sure the inside end of a tube or square port is at least the equivalent of one vent diameter away from the back of the box or any bracing materials.

Keep the vent free from anything that may affect air flow through it.

The port should also be placed as far away from the speaker cone as practical.

and this came from "The Cookbook"

Fb - is the tuning frequency of your enclosure in Hertz.

Lv - is the length of your port in inches.

R - is the inside radius of your vent tube.

Vb - is the internal volume of your enclosure in cubic inches. To convert cubic feet to cubic inches, multiply by 1728.

If you want to use multiple ports, divide your enclosure volume by the number of ports you want to use, then use the result of this calculation as your Vb in the formula below to find out how long each port should be .

If you want to calculate square vents, the formula below will give you the value of R to use in the formula above.

In the formula above, a is the area of your square vent (height x width), and (Pi) is approximately 3.141592.

I own that book, its right here next to me. //content.invisioncic.com/y282845/emoticons/smile.gif.1ebc41e1811405b213edfc4622c41e27.gif

 

[SicAudio 5,000+ posts]

then maybe you can help me out here

cuz even the OP just reinforced exactly what i said...

 

[SicAudio 5,000+ posts]

port AREA has to remain constant period...

 

[RAM_Designs 5,000+ posts]

If I ran them series, bridged, i would be at 4 ohm....

You said you have SVC4ohm woofers, correct?

 

[RAM_Designs 5,000+ posts]

port volume has to remain constant period...

You mean port area? Yes, it does. In your case, you're wanting to double the total port area...

 

[RAM_Designs 5,000+ posts]

cuz even the OP just reinforced exactly what i said...

No, he didn't. A 12"x2" port branching off into two 12"x2" ports does not equal the same port area.

 

[Try2makeitwork 10+ year member]

yes, 2 4ohm svc subs.

port volume at the front is 24^ inches 2"x 12", at the back of the box each port is 12^inches 1"x 12, so 2 sides at 12^in=24^inches, consistent.

 

[RAM_Designs 5,000+ posts]

yes, 2 4ohm svc subs.

So you're going to have an 8ohm load when wired in series.

 

[Try2makeitwork 10+ year member]

So you're going to have an 8ohm load when wired in series.

Yes, but from my understanding, correct me if im wrong, but when you bridge 2 channels, from stereo to mono, dosent the 'wired' ohm load get divided in half. so 8/2=4

 

[RAM_Designs 5,000+ posts]

Yes, but from my understanding, correct me if im wrong, but when you bridge 2 channels, from stereo to mono, dosent the 'wired' ohm load get divided in half. so 8/2=4

Each bridged channel will be operating at 4ohms when bridged to an 8ohm load. So just take what the two channels do at 4ohms, add it together, and that'll be your output at 8ohms bridged.

 

[SicAudio 5,000+ posts]

so when did 12*2 not = 12*2...

you adjust the volume by adjusting length...

when you split a port you still keep the area constant...

what you are proposing is like using a reducer on a round port and going from 4" to 2" or 4" to 6" and it changes the tuning!! how can you not possibly understand that?

the port area and length determine the tuning!!! whether you split it or not!

you just have to account for the split by adjusting the length of the L's... they both are additive in the total overall port length..

omg it is like talking to a wall...