Subwoofers, hilo para hablar todo lo relacionado sobre Subwoofers.

Iniciado por Rave Cristiano

No te referiras a los que fijan el altavoz a una pared que colinda con una sala trasera?

Si es así, confirmas que en teoria el grave es mejor pero no si esta mejora se produce en términos de SPL o de extensión.

Anyway, thanks.

Anímate al mundo "infinito".

Infinite Baffle FAQ

What is an IB (Infinite Baffle) Subwoofer System?

In very simple terms, an IB is basically an extremely large multi-driver sealed subwoofer system. In more detailed terms, an infinite baffle is a unique type of subwoofer alignment where the drivers are mounted on a sealed baffle in free air. The space behind the baffle is generally very large... typically several times the Vas of the drivers used. Large adjacent rooms, basements and attics commonly represent this large free air space. It is easiest to think of its advantages by comparing it to smaller sealed designs where pressure builds up in the box as the drivers move. To maintain steady output as frequencies drop lower, greater demands are put upon a driver causing excursion requirements to increase at an exponential rate. This effect is greatest in the infrasonic range, which is effectively around 20hz and under. As pressure increases in a small sealed enclosure, the more force it will take to maintain that steady output, which will require more power and result in potentially higher distortion. By enclosing the drivers in a large space the ‘air spring effect’ caused by small enclosures is removed. Ultimately all cabinets introduce coloration in one form or another, and the idea behind an IB is to completely remove this so as to hear only the bass in one of the purest and cleanest forms it can be heard. Additionally, with no damping effect from a 'cabinet', the drivers in an IB are more efficient meaning more SPL per watt than traditional sealed enclosures. Because of the need for this extremely large sealed space behind the drivers baffle, the subwoofers are usually mounted on a wall or ceiling opening into a large area. The rear of the baffle must be acoustically sealed from the front of the baffle, therefore a large baffle like a wall or ceiling works great. Careful consideration should be taken in choosing the placement of an IB system since it can be difficult to move after installation.

The definition of an infinite baffle comes from the idea that the drivers are mounted on a very large baffle (infinite baffle). The rear wave of the driver is completely separated from the front wave of the driver by this very large baffle. To help better understand what a baffle is, the images below show the baffle on a small sealed enclosure and also the wall being used as the baffle, with a manifold recessed into the wall. The drivers are mounted so that they fire into your home theater or listening room.




There are numerous choices in how you might install your drivers in an IB system. Below is merely a few various examples of manifolds and line arrays that are attached to floors, ceilings or walls.



As already eluded to, typically a wall, floor or ceiling is used as the baffle. Think of the baffle being totally infinite, which in reality is impossible since you cannot have a never ending wall between you and the drivers. However, take your imaginary never ending wall, and begin to fold down parts of the wall... basically wrapping it around the person standing on the listening side of the baffle, until it completely encloses the person in a cube. The baffle is now infinite in the same way as the edge of a circle is infinite, in that it has no beginning or end. It is akin to making a sealed sub with the driver mounted the wrong way, but make it so big you can get inside and set up your home cinema in there, and add enough drivers so it works as a bass system. The IB is effectively the inverse of a room sized sealed sub. The outside world is then your subwoofer enclosure (also theoretically infinite, yet very rarely is). The reality is that this outside world is made up of the rest of your house. As such the enclosure is no longer infinite (and the drivers are designed with this knowledge), but it will not affect your IB system as long as the enclosure is not so small it alters the Q of the system. The rear volume (the outside world) should ideally be at least 10 times the Vas of all drivers combined or the point where the drivers Qts equals its Qtc. With an IB driver, the driver is not designed to be loaded to result in a system Q, the driver is made with its system Q native to where it should be already. 10 times Vas is considered the normal requirement, with 4 times Vas generally considered the cut off point at which it will be unworkable.

Vas: Measured in litres (L), is a measure of the free air 'stiffness' of the suspension - the driver must be mounted in free air. It represents the volume of air that has the same stiffness as the driver's suspension when acted on by a piston of the same area (Sd) as the cone. Larger values mean lower stiffness, and generally require larger enclosures. Vas varies with the square of the diameter.

Qts: A unitless measurement, characterizing the combined electric and mechanical damping of the driver. In electronics, Q is the inverse of the damping ratio. The value of Qts is proportional to the energy stored, divided by the energy dissipated, and is defined at resonance (Fs). Most drivers have Qts values between 0.2 and 0.8.

Q (Qtc): The system Q is the characteristic sound of the bass system. Higher values represent a focus on upper bass impact, while lower values focus on low cleaner frequency reproduction. You cant have both in your system, but there is the middle of the road which is considered the optimal balance of upper bass punch and low bass rumble, and that is the .707 value. IB specific drivers are designed to give a good balance in a non loaded system close to the .7 figure, while normal drivers are not, which is why many non IB specific drivers are of questionable use for an IB.

What is an IB (Infinite Baffle) Subwoofer System? - Home Theater Forum and Systems - HomeTheaterShack.com

Finished IB Projects Photos - Home Theater Forum and Systems - HomeTheaterShack.com

IB - Infinite Baffle Subwoofer Build Projects at Home Theater Forum and Systems - HomeTheaterShack.com

Un abrazo.

Israel