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von Ah 27th August 2012 06:21 PM

Boxsim is fun! (Full-range plus woofer project)
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So I've spent a couple hours playing with Boxsim. It is a phenomenal tool, and fun to play around with.
I know that I am just barely beyond the "groping around in the dark" level of expertise, so I have a very simple question for a potential simple two-way design:
If I switch the polarity of the tweeter and it makes the theoretical crossover region look flatter, is that a feasible thing to try? Or would that cause phase problems?
The hypothetical project includes per speaker (I have the drivers, inductors, and enclosures already):
  • one 4 ohm woofer (PE buyout 6.5" woofer)
  • one 8 ohm full-range as a mid-tweeter (TB W3-881SI)
  • the woofer is in a sealed 11L box
  • the "tweeter" is enclosed in a sealed 1L chamber
  • the woofer has only a simple, big inductor low-pass ~250 Hz
  • the "tweeter" has no crossover

Lemme have it, wise ones. :D

bigdh31 27th August 2012 06:36 PM

If you are trying to avoid using a crossover it might be better to run the woofer full range and use a capacitor to high pass the mid-tweeter. You will not get much effective bass out of it anyway.

mondogenerator 27th August 2012 08:47 PM

it sounds like you are fairly competant, if you have imported your own frd etc. It took me a while to figure out. To be honest i love Boxsim. I usually rough out a crossover, then run the built in optimiser. Its a bit robotic, but if your discriminate in which components are selected then its ok. I have also thought the same as you, in the past. If in doubt, try the tweeter phase either way, run optimiser, and see which has the best phase plot. With 1st order, i would say the 'in phase' tweeter, is usually preferred, and i would expect it to work better. The max volume plot tab may be worth a look. With the small TB driver, say 95dB? thats my guess. I think there should be a high pass...i have the W3-1285SG ana they sound good, but they sound great, when SOME bass has been filtered out. The sound gets 'dirty' around 90dB if you dont highpass a tiny bit.

Thats all the critique i have! The Lowpass looks quite good, maybe going 2nd order with a 1st order on the tangband? Maybe that would also work?

aeronautical 27th August 2012 09:04 PM

Pardon my ignorance but what is Boxsim?

I am making an assumption that is is a computer analysis/planning tool to size boxes?

Where can I get it?

mondogenerator 27th August 2012 09:17 PM

the free download can be found fairly easily, using your preferred search engine. Id post a link, but im writing on my mobile. :D

its a simulation tool, free release from visaton, and it comes with archive of their drivers. It sims alignment, crossover sim, baffle and port location effects. No TL alignments, it has some limits, but its powerful. You can however, import your own .frd and .zma files. You just edit a boxsim driver project, edit the driver profiles, import frd zma, save. At least thats how i did it!

mondogenerator 27th August 2012 09:36 PM

also, to the original poster, i would suggest maybe less inductance on the woofer, and maybe a resistor to lower the tweeter a little? To be honest, id sim a 1st order on the woofer, and just a cap on the tangband, in phase, at 300hz ish rather than so low. It may be better still to use a 2nd order on the tangband, and just a coil on the woofer. Without your frd and zma i couldnt say any more lol

Keriwena 27th August 2012 10:04 PM

English version:

Visaton - Lautsprecher und Zubehör, Loudspeakers and Accessories

aeronautical 27th August 2012 10:17 PM

got it...thanks

Ron E 28th August 2012 12:59 AM

One limitation seems to be that horns are not properly calculated - other than that this seems to work pretty well!

von Ah 28th August 2012 02:05 AM

Thanks, mondo!:up:
I ended up with nothing on the TB because there was always a significant bump at the high pass frequency whenever I put one in the crossover schematic, and wide open in a 1L enclosure lends its own acoustic slope (so I've read).
Also, the guys over at PE TechTalk seemed to think this particular woofer has nasty breakup modes above 300 Hz, so that's why I chose the bigger inductor. Also Also, the simpler I modeled the crossover, the better the impedance plot looked. :shrug:
I'll keep playing with it and update the thread with other simulated responses.
It'll be fun when I actually slap all this together an' give 'er a lissen. ;)
Cheers! :drink:

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