Pontiac G8 4th order ski pass blow through design help

[Cole Trickle 10+ year member]

Looking to put a system together for my 2009 Pontiac G8.

Already have all the equipment and was considering a sealed box but I kind of want to try something new. I have built a bunch of cars/boats with both sealed and ported boxes but have never tried anything with a blow through.

This thread gave me the idea..

http://www.caraudio.com/forums/car-audio-build-logs-cars-trucks-suvs/478389-taylorfades-4th-order-ski-pass-blowthrough.html

Would love some ideas or design help. Can I make a box of this type sound clean and play all kinds of music?(am I crazy or should I just build a sealed box with 1.7' and call it good)

Car has a big trunk but the opening is about 36"(I can get any measurements needed)

Parts list:

HU-Pioneer AVH-X4800BS

Front - Image Dynamics IDQ65cs

Rear - Polk db651

Subs -Rockford Fosgate P1S2-10

Amp - Alpine PDX V9

Click to read more...

 

[BSchrowang]

If done right a 4th order will play any music that you throw at it. If done wrong it will be a 50hz fart box. You need to get a sealed box and test cabin peak. Then set turning accordingly. Someone will jump on here and give specifics soon im sure. But sounds like a sweet project

 

[iLL Ridge 10+ year member]

Do it and let us know how it came out.

I'm thinking about doing one also.

 

[Cole Trickle 10+ year member]

If done right a 4th order will play any music that you throw at it. If done wrong it will be a 50hz fart box. You need to get a sealed box and test cabin peak. Then set turning accordingly. Someone will jump on here and give specifics soon im sure. But sounds like a sweet project

Do it and let us know how it came out.I'm thinking about doing one also.

I can build it with dimensions/plans but I'm a tard when it comes to understanding the science that goes into box tuning....lol

I would just end up smoking $180 worth of subs and wasting a sheet of mdf if I came up with the design//content.invisioncic.com/y282845/emoticons/biggrin.gif.d71a5d36fcbab170f2364c9f2e3946cb.gif

 

[BSchrowang]

Well i cant remember specifically but i think you are supposed to tune 3db down from cabin peak? So you start with a sealed driver, 10 or 12 will be fine, then put the sup in the middle of the car ( i think) and play a sweep from 25hz to 100. The loudest frequency is the cabin peak. You can do it by ear or use an spl meter for most accurate results. Then once you find that you can start designing. What are you after in sound? Massively loud or pretty loud and can play most or loud with a massive bandwidth?

 

[Cole Trickle 10+ year member]

Well i cant remember specifically but i think you are supposed to tune 3db down from cabin peak? So you start with a sealed driver, 10 or 12 will be fine, then put the sup in the middle of the car ( i think) and play a sweep from 25hz to 100. The loudest frequency is the cabin peak. You can do it by ear or use an spl meter for most accurate results. Then once you find that you can start designing. What are you after in sound? Massively loud or pretty loud and can play most or loud with a massive bandwidth?

dumb question what is a "sup"

Any recommendations for a good cd or itunes download that will play the tones....looked at amazon the other day and CD's are pretty much gone...lol

I have a single sealed 10" box laying around that I could definitely get a reading from and start the process.

I would be happy with pretty loud that can play most music. I'm not going to be entering any DB drags or SPL contests I just want a clean system that performs to it's fullest potential given the equipment.

I typically lean towards SQ builds but would like to try something else if it works better for the car and could eliminate trunk rattles.

 

[BSchrowang]

Whoops i meant to say sub. The way the box size matters is a larger sealed chamber will increase low end extension. A larger ported will increase output. A common ratio is 3cubes ported per 1 cube sealed aka 3:1. I was hoping for some other people to hop on here and confirm how to tune then. I havent built one yet but i have looked into them and considered it for a while.

 

[BSchrowang]

I just use an app called signal generator with my iphone. If you dont have an iphone then you can usually downloadthe tones onto a flash drive and play them that way

 

[Cole Trickle 10+ year member]

Whoops i meant to say sub. The way the box size matters is a larger sealed chamber will increase low end extension. A larger ported will increase output. A common ratio is 3cubes ported per 1 cube sealed aka 3:1. I was hoping for some other people to hop on here and confirm how to tune then. I havent built one yet but i have looked into them and considered it for a while.

I appreciate you walking me through this....After some research I have a pretty good idea (aside from the port size) of what I'm getting myself into.

Honestly I think the volume needed at 3:1 with the 2 RF 10's is getting into a size/weight realm that I just don't want for the car.

So if the subs need .70 sealed each I am basically looking at a box with an overall volume of say 5.5'...That's going to be a huge box for the trunk at roughly 13"H 36" W 25" D

 

[iLL Ridge 10+ year member]

I've seen boxes from 1:1 on up.

From what i've seen 2:1 is common.

Even at 2:1 with 2 10's.... the box size is going to start getting big-- even with an aero port.

I'm thinking about testing my single 10" with .5 sealed, 1.0 ported 6 inch aero.

Not sure what to tune the box to though-- maybe 50hz

 

[CSCStang]

I appreciate you walking me through this....After some research I have a pretty good idea (aside from the port size) of what I'm getting myself into.
Honestly I think the volume needed at 3:1 with the 2 RF 10's is getting into a size/weight realm that I just don't want for the car.

So if the subs need .70 sealed each I am basically looking at a box with an overall volume of say 5.5'...That's going to be a huge box for the trunk at roughly 13"H 36" W 25" D

Rule of thumb in port area is one half the cone area of the drivers. Typical tuning starts at ~45hz. I caution you that trunk 4ths rarely work well.

Sent from my SCH-I605 using Tapatalk

 

[Cole Trickle 10+ year member]

Rule of thumb in port area is one half the cone area of the drivers. Typical tuning starts at ~45hz. I caution you that trunk 4ths rarely work well.
Sent from my SCH-I605 using Tapatalk

Thanks for the info...the more I get into it the less I want to do it.

I thought trying something new would be cool but I think I'm just going to run a sealed set up. Always been a fan of SQ in cars.

In my boats I like big ported boxes with 12's and a ton of power to get the Bass out of the vessel onto the beach.