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[Dave Rickard]

BHFProfessional wrote on Tue, 07 December 2004 05:00

Figure 1 : Response curve for two Crushers, stacked, in 2 pi space.

Are the graphs simulations or measurements?

Dave

[[x]]

They are Hornresp Simulations. Right now I can't build the thing, since I'm still at school, and I have some other priorities for winter break, but I'll probably have a test version built by next summer so I can measure, unless someone else would be interested in building a test box. The simulations Hornresp produces are generally regarded as trustworthy.

[Walt de Jong]

Hello,

Your Crusher is larger than a Punisher. What will the benefits of the Crusher be compared to the Punisher?

Will it go louder or deeper?

Best regards,

Walt

[ChainedDragon]

for one, the driver is easy to get, esp. in the US

[[x]]

The Crusher is a fairly efficient horn, and really about as efficient as the Punisher. The enclosure is not as wide as a Punisher's enclosure, by about 4 inches. It is about 3 inches taller. How do I justify the extra size? I wanted to make this horn good to 40 Hz, and you just don't get that without a big mouth. This horn is geared towards providing LF extension, whereas the Punisher might have a "punchier" sound good for dance music. Another thing the Punisher has going for it here is its very high power handling. I should email Eminence and see how their RMS power ratings compare to the AES rating that the Ciare driver states. I wanted to focus on LF extension because I want to get that lowest note on a bass guitar, and I know that extension can be an elusive goal in a small horn. However, I use the entire front panel for mouth area, so it's not like it's wasted space. My horn is 4" wider than John Sheerin's HL10 horn. John was invaluable in his assistance to this project.

I did, however, make an interesting discovery relating to the horn's lowest usable frequency. I had been using old numbers for my path lengths. New numbers are a fair bit longer, and the result is that you can get 43 Hz (usable, -5dB) from just TWO horns. Four horns get flat (-0dB) response to 45 Hz and have usable response to 39 Hz (usable, -5dB)! But it's not surprising when you have over nine feet of horn in the enclosure! This surpassed my own expectations.

I'll probably ask for a simple CAD program for Christmas, so I can produce some more accurate detail prints, so for those of you who aren't in a hurry, just wait on that. They should be ready by the end of January if I get this program.

So, Walt, to answer your questions, it doesn't go much louder, but it goes deeper by a small amount. And to prove I'm not blowing smoke here, here's a new Hornresp plot for four boxes, ground stacked. Yay for deep horn bass. It's no LABHorn, but it should be able to do what most people want it to do. And if you want the really low stuff and are willing to deal with a huge box, then go ahead and build a LAB.

To power the thing, the Crown Xs900 should be a good match for four boxes. Each channel powers two boxes. Power handling of the HL10 driver is 300w RMS.

[ChainedDragon]

I will ask my friend If he would put it into cad for us




will it matter much if the program used isnt "offically" his? I do bleave he got it from school.

[[x]]

That shouldn't matter. If it can make a file we can open (*.dxf, *.dwg, or *.jpg) then it's good. If he has an educational license from his school, or if he goes to a school that has a site license for the software, then it's legit.

[Walt de Jong]

Can you please give me the parameters you entered in Hornresp? I would like to do some simulations in AJ-horn to compare the Crusher to the Punisher!

Best regards,

Walt

[[x]]

Just post up a 1w/1m sensitivity response curve for four Punishers, half space. I've already posted one, so people can look and see for themselves what differences there are between our two designs which, despite their obviously different priorities, seem to be competitive with one another. My response curves have no smoothing, but the throat and rear chamber resonances, which do not affect the response within the passband, are masked to simplify the curve.

However, since my design is freely available, and I have no "trade secrets" to protect, I will do my part and post up the Hornresp parameters. McBean's Hornresp is generally regarded as a very trustworthy simulation program for horn response.

Well, I went ahead and calculated actual SPL curves for one, two, four, and six boxes, instead of just using the 0.5xPi, 1.0xPi, etc. control in Hornresp. The response curves are the same, but the actual net sensitivities are much higher. I'll post Hornresp parameters and SPL charts for all four combinations.

First: One box, Hornresp Parameters.

[[x]]

SPL curve for one box. As you can see, it's not pretty. That's why I do not recommend using only a single enclosure, but instead using at least two.