Help developing Hornresp parameters from plan

Probably worth hopping onto the hornresponse thread on diyaudio forum, David the author of hornresponse is very helpful and I'm sure he would like to see modeled versus measured results.

mobiele eenheid wrote: I modeled the horn as an 'off set driver horn' as that is what a Punisher is Strictly speaking it is but that doesn't guarantee that the HR offset model will be the best fit. IIRC when modelling Cubo Kick I found that the off set model in HR best predicted the low frequency corner while the standard entry front loaded horn gave the best prediction of the overall frequency response and sensitivity. Typically for a standard entry front loaded horn, the first horn segment is added to the Vtc and the horn length starts at the middle of the driver, this will also give you one extra segment to play with. I would look for the best fitting model and even that might be different from measurements. It's unlikely you've measured in a perfect 2,0 pi environment, T/S parameters probably deviated from the average you've used to simulate, etc. Looking at the sudden jump in flare rate the horn makes at about 30 cm away from the horn mouth a single exponential segment isn't the most accurate description IIRC earlier versions of HR gave 3 dB for a doubling of cabinets. If you think about that would mean 16 cabinets would become more then 100 percent efficient, so less and less then 3 dB per doubling of cabinets actually makes sense. Plus at some point the distance between cabinets would simply become to large to fall within / wavelength for a given frequency. Hope that helps.

toastyghost wrote: For what it’s worth, for a horn extension like that to be worthwhile it needs to be large. Very large compared to say two punishers. The gain is from directivity improvements, and for the X Horn, is about 3-5dB overall. It doesn’t really extend the low corner by more than 3-5Hz either, even in a block of four subs with four horns. It does reduce distortion of course, and flattens the overall ‘rising response’ toward the upper bass region so ‘feels’ deeper.

I dont really have much knowledge about whats going on inside a stasys X, but it appears to be a ported horn, as i'm sure you are aware, the punisher is a FLH. How comparable is the stasys X to the Punisher when it comes to attaching a horn extension?

3-5dB sounds pretty meaningful, we run 2 blocks of 6 punishers for bigger shows, to get 3-5db of improvement, would we not need to double that therefor double our amps?

3-5hz extension also sounds very useful, the difference between 40hz and 35-37 seems like a big deal. That could get punishers in too the realm of sub bass.

After experimenting in hornresp with every attribute of the horn, (length, mouth area, chamber sizes), I could not get it to produce a response close to what im looking for with out drastically changing the values.

I started to suspect it may be an issue with the TS parameters Ciare has provided. As a sanity check, I simmed a couple of other drivers just to see what would happen.



Edited by citizensc - 23 November 2019 at 12:47pm

I'm with Toasty on the idea that any gain to be had in absolute spl, is down to improvement in directivity, i.e. the energy going side and behind is kept forwards, adding cumulatively to forward energy. Goes with the concept of "throw" actually having some sort of meaning.

Given the ball ache off working out how such a horn extension may work, more ball ache from constructing and transporting such a beast, wouldn't a simpler solution to just used an increased number of sub boxes to use line array theory to get more bass going forwards, rather than behind or sides? i.e. the length of your array of subs approaches the wavelength of the frequency your interested in.

Seems to be fashionable, not least for the directivity purposes of noise nuisance abatement. Surely if done right, you get the SPL benefit, as well as lower corner benefit? Equally for ease of deployment in field, just saying "stick these subs in a straight line, with a 1m gap between them" is easier than the plans to construct a wire tensioned steel horn mouth?

I doubt you will find a Punisher in EASE .gll files, but you could load in something similar, and just build virtual arrays to see what sort of length of array and spacing of array effects spl and frequency. EASE has got a sub array option when you load in your sub, but you may have more fun dropping in individual boxes and delaying and arraying to get a feel for messing about.