Im helping a buddy redo his horrid box and have come to the conclusion that hes either gotta ditch one of the subs or go IB since he cant get rid of all the trunk space. Anyway 2 questions for you IB guys.
Has anyone on here done an IB setup on an rx8? Also, would 2 12's IB still be louder than 1 ported? Im just not sure if cone area is still king when comparing the 2 even tho in my mind it seems like a no brainer.
Lastly what type of total trunk airspace do I need to be looking at. I have heard things like 3x cone area... or 2x sealed reccomendation. So let me know what you guys think, Im ready to try somthin new and learn about somthin new along the way.
You have to half power handling for IB, so the two drivers will still only take the power of the single ported one
Ported box will be tunable, so extra output can be dialed in where you need it
To model IB the typical recommendation is 3 x VAS, though have seen 5 x VAS touted too.
You have to half power handling for IB, so the two drivers will still only take the power of the single ported one
Ported box will be tunable, so extra output can be dialed in where you need it
To model IB the typical recommendation is 3 x VAS, though have seen 5 x VAS touted too.
Half the power handling is actually a plus for this, which is another reason this idea came to play. I know the ins and outs of ups and downs of ported and sealed, just nothing of IB other than how to physically do it. If he had more trunk avail it would be easy to say ported... as I think everything should be ported based on tunability.
Half the power handling is actually a plus for this, which is another reason this idea came to play. I know the ins and outs of ups and downs of ported and sealed, just nothing of IB other than how to physically do it. If he had more trunk avail it would be easy to say ported... as I think everything should be ported based on tunability.
Thats what I was looking for 3x vas. Thanks
What's the shelf like? Never looked at one, would be my biggest consideration.
Model with 3x and 5x VAS, shouldn't be much in it, but worth checking both.
What's the shelf like? Never looked at one, would be my biggest consideration.
Model with 3x and 5x VAS, shouldn't be much in it, but worth checking both.
I dont think the shelf will be doable for the mounting. I think it will have to make a wall between the rear strut towers and vent up through the rear deck on the front side, then seal of the rest of the trunk like normal. I will model the vas when I get off today, but it looks like things are exactly what I was looking for.
I can tell you the difference between the 2. You are going to get a more natural low end sound with a lot of bottom end punch from the IB setup, if its done right. The vented setup will give you a stronger kick across a wider range of the upper frequency, with lower output in the super low range. In all honesty, if your looking for spl just go with the vented setup. The effort it will take to get an IB setup in that car wouldn't be worth it. I will say this though. If you want to see the windows flex in the low 20's then go IB.
I always liked showing people how my 2 12's with no box and only 160watts would make the windows flex more than their 2k watt system. :-)
I can tell you the difference between the 2. You are going to get a more natural low end sound with a lot of bottom end punch from the IB setup, if its done right. The vented setup will give you a stronger kick across a wider range of the upper frequency, with lower output in the super low range. In all honesty, if your looking for spl just go with the vented setup. The effort it will take to get an IB setup in that car wouldn't be worth it. I will say this though. If you want to see the windows flex in the low 20's then go IB.
I always liked showing people how my 2 12's with no box and only 160watts would make the windows flex more than their 2k watt system. :-)
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Got any pics of said install or is yours the one on here that has the rockford amp pushing 2 12's on the rear deck?
It's a bit dishonest and inaccurate to say "IB will only take half the power as sealed" and just leave it like that. When talking IB vs sealed, IB has the exact same output potential as sealed since it's all about displacement only IB will require much less power in the lower frequencies because it's much more efficient. Or said another way, IB has lower power handling because the sub is so much more efficient, you hit the mechanical excursion limits of the subs with less power. Hitting the excursion limits with as little power as possible is a very good thing.
With a proper subsonic filter, IB will have the same output over the entire bandpass as sealed but require much less power, sometimes significantly less power down low. I've modeled a few where IB requires 5x less power at 30hz as the same sub in a small sealed box. If you don't use a subsonic filter and you limit excursion down low (to protect the sub from bottoming) by reducing overall power, it's not going to be quite as loud in the upper frequencies as sealed.
For example, the subs may hit their mechanical limits at 200w at 20hz but take their whole 1000w thermal power handling rating at 50hz where not as much excursion is required. With the sealed setup, the box, the air spring mechanically limits excursion down low, making the sub very inefficient and power hungry. With IB you can use a subsonic filter to limit power down low to keep excursion under control. IMO, it's much better to limit excursion by limiting power than to make the sub so inefficient that it can't hit it's mechanical limits.
IB tends to have a very natural sound and will get loooow. There are many advantages to not having to run as much power for the same output from lack of power compression, less distortion, and less strain on the car's electrical system.
It depends on the subs and enclosure but a single ported 12" will likely have more output at the tuning frequency than the dual 12s IB. IB will almost certainly have the flatter response. At some point in the bandpass, IB will have more output in the upper frequencies due to the cone area and the vent is not adding much. Obviously below tuning frequency of the ported box, IB will be louder as well due to the cone area and the port not contributing much.
Don't get too caught up in 3x Vas and all of that. Car IB is not true IB, never will be. Even with my pair of 15s, there's very little change in response going from 10 cubic feet to 100 cubic feet. It's really made out to be more complicated than it is. Even if the trunk is on the small side, it's still going to have more volume than any box you could fit in it and you're going to get all or most of the benefits of a 3x Vas "IB" setup. Now that I've experienced IB with several subs, I can never go back to sealed as long as the car and installation allow IB. I would do ported before I would do sealed.
But again, IB vs ported, your choice. Ported will likely be louder at some frequencies but IB has it's advantages as well. Think of it this way, if you think a pair of 12s in a sealed enclosure would be loud enough for you, the same pair of 12s IB will be loud enough for you.
'84 GN 10.60@ 127mph. Infinity 3.5 coaxials and a cheap Sony HU.
Also, IB isn't going to have more output than a sealed box in the lowest frequencies assuming the sealed setup is able to hit it's mechanical limits before it hits it's thermal limits but it's going to require a heck of a lot less power to get there.
'84 GN 10.60@ 127mph. Infinity 3.5 coaxials and a cheap Sony HU.
I did an IB install for a friend with an 04" Mazda RX-8 w/ Bose. I was asked to help since he bought my other friend's subs and I have a 04" Mazda 6 w/ Bose (no Bose anymore).
The set up was a pair of Hertz HX300's, getting about 600 watts at 2 ohms for the pair. The baffle was mounted to the bottom of the rear deck, subs firing upwards.
The most important thing I will suggest is sound deadening.
From the previous install those 12"s were in, I know they can easily take full rms power in IB, with the subsonic filter set properly to reduce the excursion at the lower frequencies. Even at less than 300 watts per driver, they were rattling the sh!t out of the RX-8. I can't even imagine what it would have been like if they were used to their potential.
All in all, it was impressive, imo, very clear and low end had an outstanding presence.
I don't have any idea what ported would be like in that car, though given the size of the trunk, I would rather go IB if it was my car. If I had an RX-8 and wanted to go ported, I would fiberglass into the little rectangular hole they have at the rear of the trunk and make it flush with the rest of the floor with the sub and port firing upwards.
Single 12 ported vs dual 12's IB.
Keep us posted.
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