Modding 186 Horn

Why would they think the 186 will work in the venue and the WSX not? Modding the 186 for a lower f3 will basically make it a different cab (you need more hornlength basically).

Aren’t you going to have the same fate using 186 in a small room as the WSX? 

Edited by levyte357- - 31 January 2022 at 3:39pm

I'd like to see how 186 Horn, with approx 6.5ft horn length, compares to WSX.

Prefer 186 Horn, as it has larger chamber.

smitske96 wrote: I don't see why a 'longer path' 186 would not encounter the same problem you had with the WSX.

This ‘problem’ is not qualified by anyone that I’ve seen, and trust me - I’ve looked. There’s a ton of conjecture reported as irrefutable fact, absolutely nothing that remotely resembles a scientific, repeatable, and controlled test. Let alone analysis of the results to come up with analytical parameters to predict the behavior of the supposed ‘bass in the car park’ effect.

I’ve already looked into the effect of path length, compression ratio, and other factors affecting the radiation impedance in the free field, plus dispersion (the same below 100 Hz for reflex and symmetrical horn mouths of the same frontal area, for arrays of up to 16 boxes free-field), and the possibility that somehow the inverse distance law is violated (it isn’t).

Stacking more horns also does not increase the effective horn length. You change the mouth area, and mouth aspect ratio. If the latter shifts to >1:4 in either direction, loading is lost and directivity becomes harder to predict.

That means tall, narrow stacks such as 1 wide by 3 high are the most problematic arrangementss for any exponential or hyperbolic-exponential front loaded horn.

smitske96 wrote: @toasty It sure looks like it indeed. From the story told, i would day the space is to small for those longer wavelengths the wsx can produce. 186 does not and the 'problem' does not occur.

That’s pretty much the case for any small venue, regardless of subwoofer type. The waves simply don’t ‘see’ the walls.

There are effects caused by the rigidity and distance to nearby boundaries on the acoustic impedance of the horn, but these generally only seem to produce unwanted ripple in the power response, rather than magically transforming the horn into a magic device that teleports its output to the outside of the building.

It could however be that effect that creates an uneven response, both inside and outside the venue, and the auditory masking or unmasking makes it feel more pronounced that many small buildings pretty much don't exist at low notes.

Unfortunately since so few of the people who observe this phenomenon seem to take measurements or do controlled testing - plonk four horn subs, measure response inside and out at various positions, swap for four reflex subs of the same volume and size, repeat - it's all speculation.

The LABhorn isn’t exceptional in its length either. It’s just the standard 1/4 lambda for the intended cutoff frequency. In fact, it’s a little shorter than the basic maths suggested since a bit of response ripple was accepted to achieve the truck pack dimensions while keeping the throat expansion as intended.

If you want strong 45 Hz performance, then you can get away with a much shorter horn and load it up with power density. Look at Scott Hinson of DIYRM’s dual 18” for an example of that.

‘Modding’ a design that’s already out there is asking for trouble unless you’re going to determine the original parameters for the horn expansion, and tweak the formulae before refolding. At the very least, it’ll need a good drawing to track the volume correctly around bends and calculate the acoustic parameters for those.

Far easier to just pick your desired values for cutoff and for T, plug it into the Salmon equations, calculate the chamber for reactance annulling, and draw out the geometry in lots of equal length segments in CAD to generate the folding.

Edited by toastyghost - 01 February 2022 at 9:42am