X-Shape, next generation waveguide

Polar map with the response (SPL) without EQ can be see here :

Comparing to a OS waveguide the loading capacities is way improved, allowing low x-over and a constant uniform psycko acoustic directivity behavior pushed very hight.

On the RCF 350ND passive filter is even possible, but as this driver have a sooner THD increase bellow 1300hz, a passive cross over at 1250hz is advised (because a crossover frequency is at -6 dB on each components where they cross) :

This horn use our ADAPT technology.

Technical knowledge before explications:

A wave front moves at the speed of sound in the medium present but its edges always want to be stuck to the profile of the pavement at an angle of 90°.

It is therefore entirely “suction cupped” with its edges more or less “twisted” throughout the entire horn to end up detaching at some point anyway.

So depending on the profile, the path, certain ends of the edges of the wave front have more distance to travel and will start to deform.

We also remember that in a room with walls we listen at a so-called critical distance which is not far from 50/50, 40/60 or 60/40 ratio between the direct field, i.e. what comes directly from the speaker towards the ears and reverberated fields, or basically what bounces off the walls and reaches our ears in an indirect way.

So staying right in front of the speaker won’t save you, unless you put your head directly inside the horn.

The problematic:

Knowing this, if the diagonal opens too quickly compared to the rest, the wave front will not be able to follow in its entirety and will break, it will be destroyed but only on the diagonals.

Which means that on the vertical and horizontal polar and even on the DI it will not be visible because the wavefront will take a “perfect” cross shape, a problem that affects some rescent speaker horn and also tweeter waveguide that pass from round to square/rectangle too quickly without going through the ellipse stage.

On these horns, when we move or/and we have side walls the diagonal sound is all blown up so it gives a strange feeling of floating and change in power response the more the frequency increases (at the bottom of the spectrum no worries, question of wavelength).

But as the wave front is in fact destroy in diagonal it’s audible because of wall reflection or/and if you moove.

How X-Shape solve it

This kind of horn is a challenge to modelise due to diagonal, we understand that a very fast opening in a horn can have as a result a peeling of the wave front on the diagonal.

It’s why high level FEA is required for create a specific profile on the diagonale.

So for prove that X-Shape don’t have this problem and is perfect on diagonale the X-Shape 40 have been measured on diagonal, it’s usually the worst place for measure a horn :

As we can see there is a perfect response and the accident after 14kHz is due to compression diaphragm breakup, as usual on big compression driver.

With load capacities and Constant Directivity dehavior without midrange narrowing or beaming, the absence of Cross Syndrome is a key point of X-Shape horn. Allowing a very fidele sound reproduction.

We strongly recommand to read the midrange narrowing and beaming page for understand how this aspect is important for every horn integration for every brand.

We can provide full 4 returns for free air usage, in this case the return is glued, here completely painted:

Or a 3 sides return for facilitate speaker integration, in this case the horn is attach to the mounting system of the return, in orange (everyting will be paint entirely in black) here:

We can also see that it’s very easy to transit from a tinier radius like 12mm to the 25mm of an X25.

Everything will be painted as described here : how to finish my horn.

Of course you can also do it like this yourself in the front baffle:

In this last case you may can appreciate a 4mm face roundover for easier embedding, we can print it with this radius for a perfect feet in your baffle :

The full round-over fluid return is the most important point of midrange narrowing and beaming removing, the horn allow it by a direct ending at 180°. Each recommended round-over return radius by horn is the ideal one simulated in FEA.