quakecitystudio

In a way, IB setups in trunk cars become sealed enclosures when the trunk is closed, if the subs are firing forward from a wall that seals the trunk off from the interior of the car. Here's some examples in home theater setups though- http://home.comcast.net/~infinitelybaffled/page4IB-Gallery3.html

Here's a screen capture from Audacity - Looks to be a 40hz track

B Martin "Swoosh" Heard this guy on Hot97 http://bmartinofficial.net/ I heard about him on Hot97. Go download his free mixtape and check out his Swoosh track. This is a new rapper who's been winning contests etc. and went all the way to NYC. Since alot of people were looking for "bass scare" tracks, his Swoosh track is sure to get some people jumping on first and later hits.

I want to see the second from the bottom built.

You can play a bass cd with a track that gets down to 20 hz, but it's not going to be significant, since your box is tuned for a higher frequency. When it drops down to 20hz it will just "roll off" or not be as loud as the tuned frequency.

In general, second order is only sealed boxes. And 4th order is ported/reflex or bandpass boxes. Most people think of the 4th order bandpass box as being a "4th order" box when really any single reflex ported box is a 4th order. source: http://www.the12volt.com/caraudio/boxes4.asp The other orders are more complicated variations. But, back on topic post your design and let people help you with your issue.

That's fine, I see alot of guys do 4th order bandpass with the rear chambers being smaller than the chamber that they are firing in. Your subs would be mounted in sealed chambers right? I looked back at your screen shots and you did a calculation for the sealed chambers and one for the ported chambers. Your port is tuned to 49.58 hz? Do you know what your sealed chambers are tuned to? I know that when you have larger sealed chambers the tuned frequency is lower. I once did a sealed box for 2 12s at 5.4 cu.ft. and the frequency was around 23hz.

If I may suggest, I feel like there isn't enough back spacing in the rear chambers for each woofer, in both designs. For the first design, I'd remove the short wall of the port, and move the subwoofer wall up towards the port opening. Make sure the port area equals the surface area of the subs. For the second design, I'd change it up, so there's three chambers, two large ones and one small one in the middle. The two subs would face each other firing into the smaller chamber. It goes "large chamber" ported small chamber "large chamber. But make sure that the small chamber is big enough to be able to remove a sub.

Alpine, if you want, try setting up a flickr.com account (it's a free photo hosting site with unlimited bandwidth) . copy the url with jpg link and paste here.

I'd do a wall. As for the Enclosure, I'd construct a "horn-like" setup with the mouth of the horn being above the rear seats firing towards the front.

Do you have a build log on this?

Side note, that camera that they used to film you is one of the lastest Professional Video cameras that canon came out with: Canon C300

ahh, another Julian. Nice video!

I want to say that the larger ports tend to act like non-flared horns, in that the sound is concentrated and directional. The sound will sound louder, actually more efficient, in their directed path instead of areas around them. Also, depending on their lengths, there's the potential for frequency based energy increase which would allow it to travel farther, as well as be intensive at the mouth of the horn. I'd like to see someone build a horned wall, with the horn length going towards the back of the van, where the subs would be mounted.

I'd say for the db increase, it has to do with the backspacing the subs are mounted in. If you can increase this back area, and decrease the chamber that they fire in, as well as seal the back off, then the numbers may improve. You'd want to be able to hit 150 or more with the trunk closed. Also, I noticed that the port takes an L turn going towards the subs, how about a wider port opening, and some custom straight ports with different tuned frequencies (lengths) that you can swap out?

just looked at the build in the other thread. To possibly get louder without doing a complete change, he could do a 4th order bandpass (similar to earlier design) but with the center chamber feeding the port that goes up into the rear deck of the car, assuming the seats can't fold down. Basically three total chambers with a sub in the left chamber, one in the right chamber, firing into a center chamber that has the port through the rear deck. This seals off sound escaping through the trunk. Could probably plexi the top of the center chamber to see subs, and back light with neon. With as big of a box, might be able to add 2 more subs to the mix.

I would say that he would need to seal the motors, even though the vibrations and rippling may look neat, that is sound pressure that is flexing any surface that isn't reinforced to not flex at all. And that flexing is what's the result of low numbers on the meter, a contributing factor. Sealing the motors results in most of the sound pressure going towards the front of the vehicle, and possibly little to no flex on the trunk except that which is transferred through metal. But if I may share, take a look at a quick sketch I did of an idea for the trunk. The subs are un separate chambers firing into a single chamber that has a flared port throat of a horn that curves out towards the back of the rear seat. All of which would be sealed off from the trunk. The back wall of box of which the subs are firing towards could have a clear plexiglass to allow visibility. The horn is to project the sound waves more towards the front. Box, port size, tuning frequency would vary.

Hey Nidus, what are you doing for sound or where can I see the log? I've been thinking what if someone did a 4th order bandpass wall in a caprice classic with the box extending from the back of the front seat into the trunk - a left and right chamber that have 6 15's or 18s firing into a center chamber that is ported and firing into the front seat, it'd be a total of 12 15's or 18s depending on space, and money etc.

Slowed down one of my tracks so it's at 32 hertz for those of you that have systems that hit in this range. I'm posting the link where you can preview the track as well as download an mp3 version of it. http://soundcloud.co...32hurtz-edition Check out the track and let me know what you think. Also, I know alot of people will download the track, but it would be cool to see some SPL systems demoing the track, so download it, demo it and get video while doing so and post it in reply.

How many of ya heard this? Got some lows, highs, and drops. http://www.youtube.com/watch?v=YbPE3RqGcMc&hd=1

Here's a vid from the Krewe De Vroom Day - http://www.youtube.com/watch?v=3jPOF97ts_w&hd=1

Did you kart race saturday? I was out there both days.

I recently got to check out the new facility and also got to take a parade lap on the north track, 2.7 miles. NOLA Motorsports Park is located in Avondale, Louisiana, and features kart racing, road course racing for cars and motorcycles, 1/4 mile test and tune, and autocross pad. http://www.nolamotor.com/ Parade Lap on Krewe De Vroom Day - 4/29/12 http://www.youtube.com/watch?v=azA_-TU2VZk&hd=1

ShowFest in Tunica - May 19 - 20th http://www.showfest.com/ Facebook page - https://www.facebook.com/ShowFest

http://www.bar-b-cruise.com/calanderAR.html - There's a bunch of smaller shows, too many to list, but I believe these are regular and some classic car shows. But there may be a few audio shows in there.