Dual 18" ported box help if possible (1 Viewer)

[Dareus]

hi,

Looking to build a box or any idea for my current setup. Basically got these near new after a few car audio trades so would like to use them if possible ported.

I currently have 2 18" Re XXX subs ( yes car subs but working great )
Currently in a sealed box, parallel to a single 4 ohm load.

Behringer ep4000 amplifier and a pods signal converter.

I use it during movies for extra thump. I do have a paradigm ultracube and subs in my paradigm monitor p90 v3's which sound good buuut i'd like shaking lows
For more box office style movies with large effects and deep explosions. I dont have them on too often.

I tried a wave test and seen i get quite loud at 32-36 hz but i know ported i would go lower.
I'm seeing if anyone has used car subs before, if finding maybe subs on bottom , ports top? Ports bottom subs top? Subs bottom port in middle? Etc.

Size of box wont matter i can go up to 16 or more cubic foot.

Attaching a screen shot from my video i had as reference. Living room is more finished now but this was my setup 7.1.

 

[Dave Upton]

Hi Duncan,

Welcome to the forum.

I modeled your sub in WinISD (i used parameters for Re Audio xxx v2) and came up with the ideal box volume being 550L (19cu-ft) with a 20.8Hz tune. You could also separate the drivers into two separate cabinets, which would be more space efficient, but require more DSP/EQ on your amp.

 

[Bob Bielski]

Dave could you state what parameters you entered into the software to arrive at the desired box size. Is the software the same as using TS parameters?

https://www.eminence.com/support/understanding-loudspeaker-data/

Maybe this information can help you in your dual 18 inch design.

 

[Bob Bielski]

Just got through checking out your amp. I see it can handle running a 2 ohm load so you should be safe at your 4 ohm load. The biggest advantage of using 2 18 inch subs is they are theoretically pushing as much air as a single 36 inch sub but the excursion is lower so the stress on the cone is less and the distortion is less. The trade off on the ports is a sealed box can help with the damping factor the resistance of the air inside can help stop the cone from moving after the signal no longer exists. The ports can give you a greater lower extension at the expense of a slower damping factor, the cone may still move a little after the signal has stopped. My home theater sub has 2 ports and the lowest it can go is 16hz. It rolls off significantly after that and that is with both ports open. I can plug them with plugs increasing the transient response or speed or damping factor witch is better for music, but I run them open for movies to shake the room. Remember there is very little need for the low extension in music most music stops at 40 hz unless you are a synthesizer or organ lover, but in movies there is a ton of information that can shake you up. Try to get a grip on your room decay rate so the room gain doesn't make everything too boomy.

http://www.linkwitzlab.com/rooms.htm

Read this page and it will help you get a great low end and enjoy it with less boom.

 

[Dareus]

Thanks for the reply.

Ya this would almlst primarily be used for movies.

I already have a paradigm ultracube and when i do music i just use my 2 main speakers up front or 7 channel.

My mains are paradigm p 90 v3's.
Surrounds are paradigm monitor 9 and monitor 7's for the back.

There is enough low end for music but i like the deep rumble of the bigger subs. Also installed bass shakers in my couch a while ago.


The reply above shows a single cab and single sub. I was thinking on putting both subs in almost a single cab but port in the middle. So they are almost in seperate but only joined at the port in the center. Not sure which is best to do yet.

I'll read the article you posted thanks. I'll keep researching too until i can get the box that would work for me and go quite low.
( side note if it fails, sell and buy a svs pb 4000 )

 

[Bob Bielski]

I have an Anthem P5 amp and I believe the same company makes your speakers. My pre amp is also Anthem an AVM60. I would use a 2inch thick MDF and brace the hell out of it. With 2 18s you could probably do some damage to your house, at least the windows LOL.