Tizman Posted December 2, 2018 Share Posted December 2, 2018 Hi All. The cold weather has arrived, and its time to revisit one of the many projects that have spent the warmer months in my basement on hiatus. I would like to use the parts listed in the title to put together a two way speaker set. As per the title, these comprise a pair of FH1 bins with a soon to arrive pair of Eminence Kappa 15C, and a pair of Altec 511B with Renkus Heinz SSD1800 drivers. Some time ago, I tried to use a Behringer Super-X Pro CX3400 as an active crossover for these components, utilizing a DIY pair of stereo tube amps, but found that the noise floor of this setup was unacceptable as there was audible hiss from my listening position. Also, ignoring the hiss, my La Scalas sounded obviously superior. I have researched a number of passive crossover options, and would like your opinions on the two that I have narrowed it down to, as well as any advice you may have on the topic. I am currently looking at the ALK Engineering AP12-500 or AP12-600, or the Jean Hiraga inspired crossover (530 HZ) for Altec VOTT A7-500-8 contained in this link, http://www.vtaf.com/id107.html (modified to take into account the Kappa 15C's 4 Ohm instead of the contained schematic's 8 Ohm woofers). The attraction of the latter Hiraga inspired crossover is that it includes a filter that will flatten the dropping frequency response of the 811B/RH SSD1800 combo, while the ALK AP12 is a proven product that is in more in line with a normal Klipsch Heritage crossover. It is my intention to DIY the crossover for these speakers. Any input/advice you may have on these two choices, and any opinions as to the suitability of the Hiraga inspired VOTT crossover, would be much appreciated. Quote Link to comment Share on other sites More sharing options...
JohnA Posted December 5, 2018 Share Posted December 5, 2018 First you'll have to curve the drivers in/on the horns. Buy a copy of X-over Pro https://www.parts-express.com/x-over-3-pro-software-cd-rom--500-919 And start playing. I'll give you a copy of my design for a 902-8G/511B on an FH-1 with Peavey 1504-4 woofer for a start. The results were VERY close to the predicted response. I recommend you use the 511B so the diaphragm remains loaded well below the crossover point. The high pass filter has eq for the response bump from about 1 -6k Hz. Quote Link to comment Share on other sites More sharing options...
Tizman Posted December 9, 2018 Author Share Posted December 9, 2018 Hi John. Thanks for the schematic and graph, and sorry about the delayed response. The RH SSD1800 driver is 16 Ohm in my case, as opposed to 8 Ohm for the 902-8G. If i understand it correctly, the output of a 16 Ohm driver will be 3 DB down from the response of a 8 Ohm driver in the same two way speaker if the crossover is changed to accommodate the 16 Ohm driver. Would this be a problem with the schematic you provided? Quote Link to comment Share on other sites More sharing options...
Tizman Posted December 9, 2018 Author Share Posted December 9, 2018 Also, is the 100 Ohm resistor (in series on the switch) there to reduce the output of the 511B/902-8G to match the output of the FH1/15C? I have a spare pair of T2A on hand to drop the output as well if that works. Quote Link to comment Share on other sites More sharing options...
Marvel Posted December 9, 2018 Share Posted December 9, 2018 The 100 ohm resistor is parallel with the polyswitch... If too much power goes to the tweeter the switch kicks in and shunts the signal through the resistor to protect the driver. Quote Link to comment Share on other sites More sharing options...
JohnA Posted December 10, 2018 Share Posted December 10, 2018 Yeah, the resistor/polyswitch is tweeter protection. You size the poly switch for the current you want to allow. I ended up using the steep low pass on the FH-1 because it has significant output above 1000 Hz with the original Peavey woofer. I would expect similar with a K-33/43 but with MUCH less distortion. Quote Link to comment Share on other sites More sharing options...
geoff. Posted December 15, 2018 Share Posted December 15, 2018 Tiz, I would like to see the look on your face when you fire up those FH-1’s with the Kappa 15C’s for the first time! If you are interested, I am using a pair of Bob’s CS-500 (Cornscala crossovers) in a similar setup. Shoot me a PM and you can come up and borrow them to see how they sound on your tops in your own listening environment. I have a pair of Bob’s A-4500’s you can try on the LaScalas too... Cheers to the journey! Quote Link to comment Share on other sites More sharing options...
Tizman Posted December 19, 2018 Author Share Posted December 19, 2018 Thanks for your kind offer Geoff! I have just started the build on the crossover contained in this thread... ...so I'll probably complete that first before I take you up on it. I was at A1 Electronic Parts last week and picked up 6 crossovers from a movie theatre redo that have tons of inductors and film caps that happen to suit this crossover design, so I figure I'll give it a go. I am also interested in combining the FH1/15C at a lower crossover point, maybe around 200HZ, with a pair of Audio Nirvana Classic 10s that I have... Quote Link to comment Share on other sites More sharing options...
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