Speaker design myths revealed

Thanks for providing a link ; )

1) Larger baffles increase bass response, which is what he's after with this specific design. There are trade-off's associated with increased baffle dimensions though, but he's obviously willing to take them in order to get what he's after for use with that driver.

2) Placing the speaker cabinet closer to the wall increases bass response, which is what he's after. Like the above response, there are trade-off's involved, but he's willing to deal with them in order to get what he's after for use with that driver.

3) Placing the speaker cabinet nearer a side wall will increase bass response, which is what he's after. Like the above two responses, there are trade-off's involved, but he's willing to deal with them in order to get what he's after for use with that driver.

Have you noticed any specific similarities? Figure it out. It is a small driver that he's trying to use full range. As such, it is going to be deficient in bass response. On top of that, due to the size of the driver, it will become beamier as frequency rises. As such, the problem with sidewall reflections will be somewhat reduced as compared to designs using a tweeter or smaller midrange drivers.

With all of that in mind, I read that Nelson Pass really liked the Jordan drivers. This tells me that it obviously has some very alluring qualities to it. Whether or not it is truly suitable as a full range driver with no auxillary support above or below the midband is up to the end user. Sean
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Now Listening to: Jazz At the Pawnshop 2 / Redbook CD

Placing the driver in the center of a circular baffle will produce increased non-linearities in response. This is due to the consistent spacing in all directions of the baffle and the baffle related diffraction / reflections that take place. If using a circular baffle, the driver should be slightly offset. This causes a staggering of center frequencies that the diffraction related lobing takes place at. Radiusing the baffle and / or treating it with acoustic damping material can help, but there are tricks to this too.

When radiusing a baffle, the radius has to taper at a very gradual rate in order to achieve maximum effectiveness. Rounding the corners of a flat baffle does little to nothing. It might look prettier and produce "flowing lines", but it does next to nothing acoustically.

According to the studies i've seen, the most linear response from a driver is achieved when placed in an "egg shaped" cabinet with a slightly flattened baffle. This staggers both the quantity and frequency of baffle related diffraction taking place due to the driver having varying distances to the edge on each part of the baffle. The contoured shape minimizes the diffraction that does take place because the reflected sound waves are seamlessly directed away from their source due to the radius of the cabinet.

This is the reason that Waveform used this design on their monitors. The fact that they "textured" the cabinet also helped to break up standing waves on the baffle even further. While i did not personally like specific design aspects on some of their products, they truly were doing some innovative things that nobody else had attempted to conquer. Sean
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Think of an Infinite Baffle ( IB ) design as a dipole radiator ( Maggie's, E-stat's, etc... ) but the rear radiation never comes in contact with the front wave. The result is no cancellation or reinforcement. The driver is basically "unloaded" due to having no "pressure" on it from a small cabinet.

This is completely different from an "acoustic suspension" design, which maintains constant pressure on the woofer. In an "acoustic suspension" design, the electro-acoustic characteristics of the box volume contribute to the suspension ( compliance ) of the driver. In effect, a "sealed box" is typically a generic term for an "acoustic suspension" design, but not always. As such, an IB does NOT have to be in a sealed box and a sealed box is not always an acoustic suspension design. It can be quite confusing even though the end results are somewhat similar in performance when all is said and done.

What constitutes an IB design is that the front wave and back wave are completely isolated OR isolated well enough that the length of the path where the two waves do meet is below the usable bandwidth of the driver itself. This means a HUGE baffle area ( a wall ) if mounting it in an "open box" design. Some people with basements will mount the woofers in the floor, utilizing the entire basement as the "cabinet" for the back wave of the driver.

In effect, "infinite baffle" simply means that the front wave is "separated" from the back wave due to the use of a "baffle" of "infinite" size. That baffle can be either phenomenally tall and wide OR it can be very deep and "acoustically absorbing". Both end up making for a long signal path that encourages isolation between the front and back waves of a driver.

Some "sealed" designs are consided to be IB's when the internal box volume is much larger than the driver's electrical operating characteristics as mounted in free space. That's because the volume of the sealed box is so great that there isn't enough "pressure" generated within it when the woofer moves to alter the tuning of the driver itself. In effect, the back wave is simply "lost" within the volume of the absolutely huge sealed and stuffed box. Sean
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PS... Many drivers that are designed for use in a "free air" system work well in an Infinite Baffle design. As a general rule, IB's do not have quite as tight of bass or as good of transient response as a properly designed low Q "acoustic suspension" design, but they can be very, very good none the less.

I just found this when Googling for some other stuff. Not exactly an in-depth explanation of each design, but the basics are covered. Sean
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Simple explanations of various loudspeaker cabinet designs.

PS... I don't know what their affiliation was, but i think that Xtant was somehow affiliated with McIntosh i.e. possibly their car stereo division at one point in time prior to Clarion purchasing Mac. I could be wrong about this though....