" Free Air subs " I just dont get it.....

[jcyamaharider]

Searching for the perfect sound on the boat and my brain is about to over heat. All of my logic with car audio is not even coming close to applying to the AR. I had one 12" sub in the XR1800 and it sounded awesome, mainly due to the fact it was in the open but firing up against fiberglass shell. Tons of bass!!! I have 2 12's in this boat and I cannot get it to sound the way I want. So that brings me to the IB sub "free air". How in the heck can a sub that has no restriction on either side make bass? I understand ported boxes, sealed boxes, and bandpass boxes. I just can't wrap my head around free air. Does it work, there are many out there that say it does, but I do live in Missouri so "Show Me". Please give me some guidance or at least a warm fuzzy that I wont be blowing 275-500 bucks.

Also everyone uses the JL IB sub, but with how crazy everyone is with wetsounds I am surprised I haven't seen anyone use their free air sub.

http://www.amazon.com/Wet-Sounds-Se...1398388343&sr=8-2&keywords=wetsounds+free+air

 

[DieselCamel]

i’m getting the wetsounds sub installed should have my boat back tomorrow i’ll let you know

 

[redthumper9]

I feel your pain. I am a bit of a bass head and never liked the way IB sounded in comparison to sealed, ported etc. in cars. I was scared to cut a big hole in the boat only to find out that it would not satisfy my needs. I went with a sealed enclosure and a vent. It hits pretty hard.....but I have to be realistic and realize it just can't do what the same set up would do in a Honda Civic hatchback or CRX.

 

[redthumper9]

i’m getting the wetsounds sub installed should have my boat back tomorrow i’ll let you know

who is doing the install up around Winston Salem?

 

[DieselCamel]

who is doing the install up around Winston Salem?

Sound Fx In High Point

 

[redthumper9]

Sound Fx In High Point

Just wondering....I have a friend that owns a shop in Greensboro and was speaking to him the other day. I was pleased to find out that he could get Wetsounds gear!

 

[DieselCamel]

Just wondering....I have a friend that owns a shop in Greensboro and was speaking to him the other day. I was pleased to find out that he could get Wetsounds gear!

Not to many great shops around here. Unless you want your system hacked up by some pizza faced kid

 

[txav8r]

I don't know if you will be happy with a 10" IB sub if you have 2-12" enclosed and can't get what you want. You can get plenty of bass with IB, you may need more than one. But if your after big bass up front, I am guessing you need to check the power requirements of the 12's your driving and maybe work on their enclosures a tad. You ought to be shaking the shore! David? @David Analog

 

[Murf'n'surf]

What are you powering each 12" sub with? 1000/1?

What brand sub?

Can you make a box behind it?

 

[David Analog]

First, it would be extremely rare to find an automobile, truck or SUV where an infinite baffle (IB) subwoofer would work. An IB woofer still needs total front to rear isolation and an extremely rigid baffle like any other subwoofer. Some models of Mercedes or BMW are a candidate because of the solid rear bulkheads where the cabin and trunk are very well isolated. But it still takes a great deal of work to reinforce and close off all the small openings. When executed correctly these cars sound great with an IB sub. The real problem with IB is you are rarely exposed to an example of proper execution. And that creates a ton of misconceptions about what IB can do.
An IB doesn't apply to most towboats. But there are a few inboards and a ton of I/Os that have expansive seat or helm consoles that function as a near ideal infinite enclosure.
There is not one technical or acoustic reason that an IB subwoofer won't sound great....if correctly done. It just can't play quite as loud as an air suspension or bass-reflex woofer of the same size.
A true IB woofer is self-damped. It is highly dependent on the mechanical suspension and motor structure electrical force to control the woofer mass and considerable inertia. It is far less dependent on the back pressure of an isolated air chamber. It must have a full enclosure but the enclosure must be large enough to not impact the woofer's 'Qts' and that requires an enclosure well over two cu.ft. to infinite for a 10-inch IB woofer.
In contrast an air suspension (AS) woofer is extremely dependent on the rigidity of small trapped air mass to control the woofer.
The difference is the IB works great to a limit. It's not as linear a form of control as AS. So by comparison, the excursion of an IB is limited. Many will not exceed that limit. Others will. You probably know who you are from the brief explanation.
There are a number of quasi IB woofers that can't make up there mind what they are intended for. The JL Audio IB M series is the best IB woofer by a country mile. It is dedicated to one purpose only....IB.

 

[cybuch]

When I first installed my system, I was runn 4 10's free air and it sounded pretty good with a ton of power. Then I added 2 more with a little more power and it sounded even better. However, the boat rattled to all hell. Then I built a tuned ported enclosure for each side (3 subs each) with the same power and subs and now it throttles you! Plus, no more rattles. Tuned box is the best way to go.

 

[David Analog]

When I first installed my system, I was runn 4 10's free air and it sounded pretty good with a ton of power. Then I added 2 more with a little more power and it sounded even better. However, the boat rattled to all hell. Then I built a tuned ported enclosure for each side (3 subs each) with the same power and subs and now it throttles you! Plus, no more rattles. Tuned box is the best way to go.

Which free-air subs did you use?
A ton of unwanted vibration and resonance is a classic symptom of a non-free-air sub used in a free-air application.

 

[cybuch]

It was a kicker free air. It wasn't the sub that was vibrating, it was the whole boat, as it was being used as the baffle.

 

[cybuch]

That should have read "same number of subs"

 

[woodard1983]

Ib is not going to give you as much output as a sealed or ported enclosure...if done correctly they have been some of the best subs I have heard from a sound quality perspective though....it all depends what you want, but I'm thinking from your post your looking for more bass??

 

[David Analog]

It was a kicker free air. It wasn't the sub that was vibrating, it was the whole boat, as it was being used as the baffle.

There's part of the problem. The Kicker is one of those medium 'Q' drivers that is less than ideal for free-air. Lots of moving mass and lots of travel but not much in the way of self sufficient shock absorbers. So that's loose, undamped and that transmits vibration. I've even seen mis-applied woofers create enough vibration to cause the throttle to shift position. So that is not the result of a true IB woofer. Also, any good air suspension or bass-reflex woofer deserves a rigid .75" baffle with zero flex. Any IB woofer requires the same consideration. If it is just mounted to .3125" thick fiberglass you are going to have lots of boat resonance. Adding more woofers to the same plane taxes the structural rigidity even more. Plus, tuning, crossover selection, bass boost, can all undermine any woofer in an open field environment, particularly an IB.
There's no doubt that bass-reflex or a bandpass will pick-up extra output over IB or sealed. But excessive boat vibration is not a byproduct of IB. It's a product of selection and execution.

 

[Ronnie]

Wow, reading all this technical writing is giving me a head ache. If I add a subwoofer to my boat it's probably going to be in a box under the left rear / aft port sets behind the batteries. My simple logic being that there is room there (so no drilling), its close to the power (so less of a cable run) and it "looks" and I "assume" and hope works most like the subwoofer for my home system which I love. So the only questions I have are:

How big? What brand? Class/type of amp? How much power?

 

[jcyamaharider]

What are you powering each 12" sub with? 1000/1?

What brand sub?

Can you make a box behind it?

Murf I just put in 2 older sony explodes that I got in a good deal from a friend to put into the XR at the time then I bought this boat and through together a system in it to finish out the season last year. These subs had amazing bass in the XR, like I said, so I figured they would be fine in the boat, which they will be after I figure out how to mount them. I can put a box behind them and I think that is the route I am going to go with after reading @David Analog explanation ( Thanks David for your help ). I have a 710 watt amp to one sub and the other I have a 350 watt. One sub is for all the time play and I turn the other one on for major shore action or when we really want to crank it up.

We have stereo in almost everything we own. 2 -12's in our car, I have 2-10" dvc's in my truck, I guess I am just used to that sound.


@woodard1983 you are correct I am after not only more bass but a not so dull sounding bass. Don't get me wrong I don't want my boat to just be this thump thump going down the water, it needs to be clean and " complete".



Also thanks to everyone that posted.

 

[jcyamaharider]

I think one more thing I am going to try is a down fire approach. That is how my truck is set-up and it is amazing!! Of course I am in the same cab, but it is worth a shot right now.

 

[woodard1983]

Where are you planning on mounting them? I'm getting ready to put the sub in mine (last piece of the stereo upgrade ) and am trying to figure out where to put them....

I'm thinking I might go underneath the lounger and taking out the cubby to make a vent to let the air out...have a couple other ideas, but figured I don't need to reinvent the wheel if others have good ideas