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Maz4bz

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About Maz4bz

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    Alpine SWR 1522 DIY Budget Build Sub
    Alpine SWR 1540 DIY Budget Build Sub

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  1. The folly of a horizontal centre channel speaker.
  2. I think the first step is to buy yourself a measurement rig like Omnimic and measure the Fortes first to establish a baseline. Then make incremental changes and measure each change to quantify what your are doing. It's good to trust your ears but they can't tell you everything that is changing. You can change anything you want but splicing drivers, cabinets and crossovers I could not recommend without measurements. Speakers are called systems because the drivers position within the cabinet and their relationship to each other and the cabinet combine to create the sound you hear. The crossover is designed to tie this system of parts into a corherent whole. On that basis if you change the Fortes drivers, their position in relation to each other in the cabinet or the width of the cabinet the crossover will need to change. As I read down your list of changes I kept thinking - I'd need measurements to make that work, except for your first suggestion. I've not heard the Fortes but they are iconic. If you need to change up the Fortes that much I'd be inclined to sell them and build a proven DIY design that meets you design/listening goals. I'm all for improving speakers, my KG 5.5's have been a joy to update. But I simply could not have achieved much meaningful without measurements. But what ever you do, enjoy!
  3. I'm sure the RF-7's will be wonderful. I'd really love to get my measuring gear on the a pair to quantify the actual differences between the double 10" woofer Klipsch models. I just wish they'd set them up as 2.5way for the performance benefits of this! They must be a winning combo for klipsch or they wouldn't have been in their line for so long.
  4. Hi Dkals, Those KG's look like they're in fab condition. These are a highly upgradeable system and can particularly benefit from some crossover enhancements. I've gone all out on mine which I've documented here.... Let us know how you get on if you make any further changes.
  5. KG 5.5's are a very capable system with lots of upgradeability..... Listening to some old skool Icehouse on them now as I tap this out, they are so smooth and have a rich bass. They are my reference system.
  6. Keep it vertical or your off axis response suffers a lot (i.e. for anybody not sitting right in front of the centre speaker)….. https://www.hometheatershack.com/forums/home-theater-design-construction/175510-kind-unusual-setup-3.html#post1615066 Traditional centre channel speakers are even worse.... The folly of a horizontal centre channel speaker - RP-250C measurements
  7. Nice job George! Love the finish. So glad my KG 5.5 update ramblings have been of some value. Please post more photos. I'd really like to see how you laid out the crossover. Cheers
  8. The tweeter has a third order or 18db high pass filter which is created by C1, C2 and L1 in combination. Horn compensation when a compression driver is used is a little different and is usually formed by a capacitor and resistor in parallel. See here the Econowave crossover design by Zilch. In this design the compensation is formed by C3 & R1 for the Selenium D220 on the Econowave guide... Wayne Parham's white paper "Speaker motors and passive crossover filters" explains this well, certainly better than I can. In this case the KLF/KG and many other Klipsch horns front a dome tweeter which may explain why these don't require compensation - but I could be wrong in saying this. As I understand horns it is the constant directivity that causes the 6db decline in output which is why I was surprised the KG horn performed so well without compensation. The breakpoint or cutoff frequency or crossover frequency (Fc), if I'm correct in understanding your use of breakpoint can't really be changed without requiring a complete redesign of the entire crossover. Altering C1 affects the filter Fc on the tweeter, which will impact on the summed response of the tweeter and woofer, thereby requiring a subsequent tweaking of the woofer circuit. As I mentioned previously in this thread any changes to the crossover filter design is unlikely to yield satisfactory results without the actual KLF-10 driver frequency and impedance measurements. "Can anyone explain HF Compensation and the need for it?" Why not have a play with your CF-3's and see if you like what you hear? You can reverse it if you don't like it. Better yet get a measurement mic and see what you hear!
  9. Hi Chris, Thanks for your insights. No, I have not yet listened to a MEH. I sure am keen to try one, this SEOS based design from the master BWaslo sure is intriguing. How's that polar pattern! I would have thought the quad woofer arrangement is going to have both vertical and horizonal pattern problems? Cheers!
  10. Wow, that is one slick website you have there! Impressive. A few design questions... When you say ALK designed these specifically for you, May I assume then by this you mean that he has the same speaker enclosure/drivers/horns on hand and he has measured like this: For a three-way, measure the following (keeping the microphone position, the baffle position, and the levels the same for all measurements -- WITH phase response included): Tweeter response Tweeter + Midrange response (both together, no crossover) Midrange response Midrange + Woofer response (both together) Woofer response Would it be possible for you to post the crossover schematic so others might also build this system too please? Again, super keen to see final response measurements! Cheers.
  11. I've read with interest about the Eminence neo woofers in some of the nice DIY Sound Group designs. Unfortunately Eminence is very expensive in Aus. About that crossover - its a generic design right? Given how much you are investing here I'd be very interested in the measured response once all built up. Good luck!
  12. Great work. Just wondering if you considered using faital woofers and why you went with the Eminence? I recently did a build with the Faital Pro 12PR300 and had great results. Thanks for sharing. Keep us posted.
  13. Dear all, I good friend has built an amazing home theatre, actually its the best I've ever experienced. It has an all Klipsch front end - he was sold after hearing my KG-5.5's. , in ceiling speakers for side and surround and five subwoofers. Pioneer receiver, Behringer DCX-2496 for sub optimisation and a pair of Crown XLS... Two tapped horns for freight train levels of impact... The weakest link however is the centre channel. This is nothing new of course, others have written about this elsewhere. Nothing against the quality of his nice RP-250C. When sitting on axis, i.e. right in front of the RP-250C the vocals are crystal clear. However when on his outboard seats, I personally find dialogue intelligibility goes off a cliff. I took the opportunity over the weekend to quantify the off axis performance of his front stage, including the matching RP-160M's to see what the measurements might say about why dialogue is so difficult to catch when not in the two money seats. Using Omnimic I have a stand I've made to do measurements of bookshelf sized speakers. This sits on top a turntable with 10 degree markings for accurate off axis measurements.... The first thing we did was measure the impedance of the RP-250C. We use this to set the measurement level to approximate 1watt at 1 meter. The enclosure has a sticker on the back that says 8ohms, I'm thinking Klipsch made a typo here?!!!…. The following measurements are all taken in room, at 1 meter, with 5ms gating at 2 volts with no smoothing. First here is the complete 0 - 90 degree horizontal measurements.... Here is just the 0 - 40 degrees to help clarify the problem.... What we see here is that the RP-250C is only able to perform well in the critical 1-2khz region either on axis (0 degrees) or out to 10 degrees off axis. Not much then. Once 20 - 40 degrees off axis we can see here the suck out that is occurring. If we take this same set of measurements and create a Dr Geddes style polar map we can see more clearly the problem. First here is an ideal polar map lifted from Dr Geddes white paper on controlled directivity... Here is the RP-250C. I've added in the lines to show the extent or lack there of the sweet spot from 2khz all the way down to around 500hz.... What happens when we measure the vertical off axis response.... The irony of the poor horizontal performance is that the RP-250C has just about the best vertical off axis performance I've ever seen outside of a synergy horn.... Polar is stunning, I'd say solid performance across the board out to 40 degrees off axis.... Certainly the RP-250C looks better than the RP-160M when measured in the horizontal, which itself is no slouch, even if it is a bit missing from 1 - 2khz itself and just a bit hot above 10khz.... Traditional horizontal for the 160C... And another impedance typo? 160C also rated as 8ohms!??? 😉 So the moral of the story here is that a traditional centre speaker with the horizontally laid out drivers is a really poor option for precisely its intended purpose - delivering crystal clear dialogue to all viewers. Ideally a center channel speaker is a perfect match of your left and right, or at least a speaker with vertically arranged drivers. Three RP-160C across the front standing on end, certainly not lying flat as intended, would make an outstanding front LCR stage, provided you could keep your ears right in the sweet spot vertically! Cheers
  14. Hi MechEngVic, Glad you were able to have a play with the XSim .dxo it is a great tool. I think you did the right thing here. 0.05uF is a very small difference in value and I would be highly surprised if that was audible. I would hate it if you replaced that lovely looking Clarity Cap on the basis of what you have seen in the XSim .dxo I provided. The reason for this is that we are not using the KLF10 driver measurements for the combined system response. We would need these measurements to do any kind of granular change to the crossover, such as changing a cap by any value, especially a value of only 0.05uF, for example. My intent in sharing the XSim model was simply to show how we might address the gross difference in output between tweeter and woofers, if these have similar efficiency to the KG 5.5 drivers. The beauty of the R2 tweak I have suggested is that it works like a simple volume control on the tweeter level that you can absolutely hear the difference of when implemented into a system like the KG 5.5's which are approximately 5db hot on top. 5db is a big/gross change to the level of the tweeter that will definitely be audible. Notwithstanding I encourage you to change up your crossover however you like, its completely reversible and a fun way to learn. I would like to suggest that you can do that with nice cheap parts, like I have done in my KG thread, first. Then if you settle on a design as final, you can go nuts and spend big on parts then. Of course if money is no object please completely ignore me! If money is no object then you really owe it to yourself to get a measurement mic. Then you will know precisely the impact of any changes you make. I will very much look forward to what you find. I also highly recommend trying other values for R2, mainly as a learning opportunity, and because the 10ohms value was just a stab in the dark on my behalf - we are not using your KLF drivers in the model after all. If you try a range of values and give each change a while for you to acclimate to, I'm sure you will find a balance that suits your taste. If you then give us a "review" of each value it may help others to zero in on a value that works for them too. Have fun and good luck!
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