In Reply to: 600 Hz. with back to back BW's posted by Sam P. on May 09, 2002 at 05:41:20:
Sam,
I also would like to thank you for the info. I plan to use JBL 4648 with Altec horn/driver combo. I recently acquired a pair of Altec 311-60 horns and a pair of Altec 288C drivers with 16G diaphrams. I plan on putting a 15 ohm resistor across the 288 to give me a 8 ohm load to the crossover(115db/watt minus 3db for the 15 ohm will still leave me 112db/watt). I bought from parts express: 800hz 2-way crossover with 12 db/oct low-pass and 18 db/oct high pass. I can use your zoebel info for my 4648's. I am wondering about the 817hz cancellation prob you mentioned and will try out first. If I must, I will probably use 500hz or 600hz crossover then. I plan to use Wayne's attenuation/compensation for horn(ie: 12 db/.47 ufd cap). I know .33 ufd is probably testbook but I like a little more sizzle on the top end(derived this from running 2226J with 2418 driver on 2373 horn with 1.6khz high pass 18db and 1.4 mh coil on 2226(Jbl 3677 cabinet - remove foam from ports and is close for low power applications)) Did you run your 4648's on their sides or upright????? I am anxious to try out the 288's (1.4" throat vice 1" altec's I have used before). I read somewhere that Altec decides to use 1.4" throat instead of 2" throat to keep the high frequencies from dropping off as much. If anyone on this forum has any advice concerning the Altec 288's please let me know. The 311-60 horn has 220 hz taper and the 288's are rated for 500hz to 16khz.
Thanks for listening, Ron
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