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In the Forum: Horn-Loaded Speakers
In the Thread: How difficult is it to achieve Vox Olympian sound
Post Subject: Haha my topic :)Posted by martinshorn on: 1/3/2018
hi. That’s a nice topic. I studied the VO like a maniac. For me there are 3 topics. First was obvious, easy, the horns. The bass horn for the ak151 is housing a rear chamber slightly open, giving the injector channel - that creates a lot charme, flavor and „heart“ but also 3 dimensional projection. In the mids, the radial horn with a wide horizontal but narrow vertical dispersion gives nice neutral and open voices with little horn sound. Then, that weird trumpet on top, has a very narrow dispersion, that makes this „zoom“ like a magnifier on details, due to lower room reverbance. About the slot tweeter used >15k i didnt make my final resume yet.
Second: the drivers. As we know the vitavox got a lot of charme. But i also know that they color a bit too much above 5k, the 2nd harmonic increases dramatically.So its absolutely rational to cut it off there and go to a less coloring smaller driver. Funny, Kevin doesn’t seem to approach things so technical, still, for me the measures say „cut it off at 5 latest!“. Well the TAD above then, is really the least coloring driver of all. But the horn isnt. Interesting combination. The slot next on the very top seams to contribute very little. It’s crossed at 15k which means it’s only a cherry on the cake. And the vox palladian proofes that. Totally different tweeters, same sound.
As a third: the crossover. I know the XO points and i can assume very much the steepness chosen. Still there are likely some small EQings integrated that will give Kevins Signature. Which is exactly what Romy mentioned above. So yes, having same horns and drivers, you may not get the same result. But you could, knowing where to head to. I would even say, having horns that in principle work the same way (though looking different) and totally different drivers (though the same key core values of those used in VO) you will be still able to get the same VO sound - if you know where to head to. This can be only done properly if one retailer or Kevin would allow you to make some sweeps on each mouth. Determining the transient and magnitude of the complex system. At the end, only the harmony of on axis first wavefront magnitude, and its proportion and relation to the diffuse/indirect magnitude response will give the main sound signature. This seems to be unachievable. But having same horns, starting with same XO points, based on the CN458 in a first step, you likely get very close.
So, get yourself an approx vitavox oracle from your craftman, vitavox RH330 or similar (fostex H200, TAD H4001), a trumped like jbl 2312 and your horns are done. Buy vitavox ak15x, S2 or S3, TAD 2001/2, and the drivers are done. For the cherry, there are not many tweeters who manage the 45k like the TAd Et703 or Vitavox T9. The JBL 2405 or Fostex T825 have similar horn but only reach 20k. The Fostex T705 or T925 (old version) will manage though.Also the Fostex FD200L has a very similar construction and sound signature to the S3 (low compression 3“ aluminum diaphragm). The 18sound 2080A is similar too but more neutral less of that sound signature. Also similar to AK15x are Fostex PA38, JBL D130, Fatial 15PR400, AES TD15M ...... as a woofer (strong motor, super light and rigid diaphragm, low Qe, hi VAS, hi Qm)
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