John Chi-town Posted December 19, 2013 Share Posted December 19, 2013 I know that a stock pair of forte II produce 99db/1 watt power. I replaced my stock phenolic tweeter diaphragms with Bob Crites Titanium. In addition I replaced my original squawker drivers and diaphrams with new Klipsch K53TI drivers. Lastly I replaced my original crossovers with Bob Crites replacement. Do all of these changes increase efficiency? IE; now closer to 101db/1 watt power? I have no way of measuring and was just curious if there was a gain in efficiency? Certainly happy with the results! Best regards, John Quote Link to comment Share on other sites More sharing options...
Frzninvt Posted December 19, 2013 Share Posted December 19, 2013 Efficiency - No. Brightness - Yes. The change in midrange drivers will require modification to the stock crossover otherwise they will sound like a high speed dentist drill after extended listening. Quote Link to comment Share on other sites More sharing options...
John Chi-town Posted December 19, 2013 Author Share Posted December 19, 2013 Bob Crites made a mid range roll off for me to address what you described above. Otherwise the mid and tweeter would be working at the same time. Quote Link to comment Share on other sites More sharing options...
moray james Posted December 19, 2013 Share Posted December 19, 2013 hey John: the efficiency of your loudspeaker is determined by the lowest efficiency driver in the system which is the woofer in this case. Cabinet type does not have any impact upon driver efficiency which cannot be changed. Al Klappenburger told me once that the Fore ll is a solid 95 db efficient system. There are many methods of calculating room gain and so system efficiency but I think that 99 db is over optimistic for a Forte ll. The output of most speaker systems will roll off very quickly below 100 Hz and the given efficiency numbers can only be realistically expected above 100 -150Hz. You can enhance your low frequency output by placing the speakers closer to the wall or the corners. But your system efficiency is set in stone at around 95 - 96db for yor speakers. This is actually a very respectable value by the way. Cornwall is a little higher probably a couple of db LaScala a couple more. To achieve effiency levels over 101 db will require a lot of large bass bins and amps to run them. I hope this helps and I hope that you are still enjoying your Forte ll. My son is enjoying mine and my daughter a set of modified KLF20. Best regards Moray James. 1 Quote Link to comment Share on other sites More sharing options...
John Chi-town Posted December 20, 2013 Author Share Posted December 20, 2013 Moray; Thanks for your detailed explanation. I came up with 99db/1 watt based on the spec's from Klipsch on the forte II. Still enjoying the forte II after nearly 22 years of ownership. Still prefer over the Cornwall & Chorus lineup. What are you using today, now that you have passed on your forte II and KLF 20? Have a great Christmas and Happy New Year. Best regards, John Quote Link to comment Share on other sites More sharing options...
moray james Posted December 20, 2013 Share Posted December 20, 2013 Hey John: I have a set of KLF20 which I modified but I have been working on my brothers Heresy lll for the past year and a half or more. I have also been experimenting with Karlson K-Tubes mostly with my new to me EV1506 and EVDH1A drivers. I have some CF3 parts but I don't plan on doing much with them right now. I have been spending time with a new bicycle attempting to improve my physical condition. As long as the roads are clear of snow I can keep riding every day. Best of the season to you also Moray James. 1 Quote Link to comment Share on other sites More sharing options...
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