lightply/honeycomb cores?

[newbold]

Is anybody making cabs from these materials?

'Lightply' - honeycomb core sheet material available from, at least, husky plywood from Quebec Canada?

It's rigid and stiff and since it's all about stiffness in cab construction, I would presume this would make it superior to standard plywood.

...just thinking ahead to a future build.

[T-Bird]

Hi.

Honeycomb construction is not what one usually thinks about when selecting a void-free material to make cabs .

So, no, no-one uses it. At least not twice.

Concentrate rather on skin-core-skin composites instead, that is the way to go if weight and structural stifness are the design goals.

Regards
Sam

[Dekker]

I believe Robby at Art Of Noise Audio experimented with making fEARful cabinets using Nidacore material.

I believe the complexities of construction and the heavier-than-advertised weight eventually lead him to abandon that avenue for cabinet construction. He currently makes cabinets with a foam core epoxy fibreglass.

Your mileage may vary though! The benefit of the honeycomb comes more into play for thicker boards (requiring more strength).

Dekker

[Foz]

Ultralight Metallic Microlattices

Metal lighter than feather? New micro-lattice material is the World’s lightest material | RobAid

[dhomer]

Any plywood you choose for cab construction should be at least 5 plies and void-free. No matter what it weighs it should be a high-quality board.

A proven light weight material is marine-grade okoume. Expect up to a 35% weight reduction from baltic birch. Downside is its very pricey, and local availability might be hit or miss..

[brendanbassist]

Originally Posted by T-Bird

Hi.

Honeycomb construction is not what one usually thinks about when selecting a void-free material to make cabs .

So, no, no-one uses it. At least not twice.

Concentrate rather on skin-core-skin composites instead, that is the way to go if weight and structural stifness are the design goals.

Regards
Sam

"Taking their place alongside the familiar fiberglass are some newer, more exotic composite enclosure materials. QSC Audio new offers several products housed in a cabinet made from Composilite, a new 'hybrid' material that uses multiple skins of carbon fiber layered over a Nomex honeycomb core to form a rigid, seamless structure. JBL's Vertec line arrays take the same concept a step further by encapsulating honeycomb structures, aluminum bracing and steel components into a single composite shell. Although the process is highly labor intensive and therefore costly, the end result according to JBL is a housing that is lightweight, rigid, durable, and free from acoustical anomalies. Though currently limited to high-end professional systems, this type of space-age loudspeaker cabinet likely points the way to a wider range of new molded products that will emerge over the decade to come."
Thermoplastics 101

"Replacing a wooden enclosure
with a trapezoidal aluminum
patented² SpaceFrame that is integrated into a carbon fiber/honeycomb
composite enclosure"
http://www.jblpro.com/pub/tour/4897.pdf

[teemuk]

Originally Posted by T-Bird

Honeycomb construction is not what one usually thinks about when selecting a void-free material to make cabs .

The void free plywoods are chosen because traditional plywoods with plenty of voids are not very rigid and can therefore resonate.

A honeycomb - or similar - structure as a layer can, however, be very rigid, yet lightweight.

[seamonkey]

Floors and walls on airplanes and boats are made from this stuff.
Strong, light, expensive, and hard to edge join.
They usually have aluminum fittings to join edges. This and some air tight glue would do it. Other options are to route a channel and glue in a solid or pieces of real ply around the edges of a panel and then just use regular jointing techniques.

It is going to take some practice. If I could afford it, and had time to practice, I'd give it a try.

[Petebass]

Originally Posted by brendanbassist

"Replacing a wooden enclosure
with a trapezoidal aluminum
patented² SpaceFrame that is integrated into a carbon fiber/honeycomb
composite enclosure"
http://www.jblpro.com/pub/tour/4897.pdf

pffft.... Sounds impressive but this thing weighs 240lbs (109kg). Hardly lightweight!

[robthebassplaye]

Originally Posted by Dekker

I believe Robby at Art Of Noise Audio experimented with making fEARful cabinets using Nidacore material.

I believe the complexities of construction and the heavier-than-advertised weight eventually lead him to abandon that avenue for cabinet construction. He currently makes cabinets with a foam core epoxy fibreglass.

Your mileage may vary though! The benefit of the honeycomb comes more into play for thicker boards (requiring more strength).

Dekker

Hi,

I've performed a lot of accelerometer testing on many materials for just this purpose, and honeycomb just doesnt pan out. Composite extruded foam core / fiberglass is the hands down winner.

I just built something along these lines, and I have included all of my testing info on line, so you can see how the different materials perform.

You can find the thread here:

Ultra Light Weight Bass Cabinet

Rob

[Foz]

I suspect your even/odd harmonic distribution difference arise in large part from having different overall dimensions and placing the accelerometer at different locations on the membranes - so you are getting differing degrees of symmetry between the harmonics and are plotting the phase space of a different section of the membrane's Chladni pattern - if you were to use panels of precisely the same dimension together with similar meter placement you might find greater congruency of this element [and yield a better apples to apples comparison]. That said I doubt you'd form a different overall conclusion.

Salt on a Flat Aluminum Plate - Modes of Vibration - YouTube