Super tweeter for FullRange Driver
ENIGM Acoustics Sopranino electrostatic supertweeter Never seen these before. Wow! killer load for an amp, like most esl’s in the highs. https://www.stereophile.com/images/614EnSopfig1.jpg "Sopranino’s magnitude increases with decreasing frequency. However, with the 8kHz filter setting, there is a very high inductive phase angle between 7 and 12kHz, a region where the impedance magnitude drops to less than 2 ohms. This makes the Sopranino very difficult to drive at this setting"Cheers George |
Makes super tweeter load very mild for amplifier. For example if you use Fostex T90a and you need align it with speaker sensitivity 97dB. You connect T90a to -9dB tap. The super tweeter load that see an amplifier is 64 Ohm. You must put HP filter before autotransformer. You can use potentiometer in parallel to autotransformer input for adjust cut off frequency. |
akwilson501 wrote: "I’m trying to cross my tweeter over around 15khz, wouldn’t a .33uf capacitor be ideal, in a 1st order filter? Considering the 106 db on the fostex, and the 96db for the fullrange... "3uf and 1.5uf seem as little high doesn’t it." By all means go with whatever works! You may well be right. My thinking was this: The T90A’s contribution will all be going into the reverberant field, and its radiation pattern is fairly narrow so that on-axis 106 dB doesn’t apply. What does apply is the power response - that is, the sum of the driver’s output across all angles. So when you eyeball the factory curves, the off-axis curves are more representative of what the T90A’s contribution will be: https://www.madisoundspeakerstore.com/bullet-tweeters/fostex-t90a-top-mount-horn-super-tweeter/ Mentally average the 30 degree and 60 degree curves and imo THAT is a reasonable approximation of what you’re starting out with. Duke |
I’ve experimented for a long time with implementing a super tweeter into a single driver design and after about a year of back and forth, I decided that it never sounded completely correct. I used many values and brands of resistors, capacitors and even tried a L pad. I was working with the Fostex T90a. I came to the conclusion that to me I always felt I could hear a gap where the highs of my full range single driver cut off and where the T90a came in. Also the very highs of a super tweeter can sound bright. I had been using high quality resistors and I still experience this. I felt that the T90a never blended in as well as a good 2 way design. So if you ask me, if I had a single driver speaker and needed more energy in the top, I would be looking at high resolution cables, tubes or other tweaks that would help. Also, I strongly felt that instead of incorporating a super tweeter into my speakers, I should had went with a really good regular tweeter. Pretty sure it would had blended in better. BTW, I still have my single driver speakers and now I enjoy them very much. I use No super tweeters, just the single driver alone. I just used better cables and different tube amp. I also own these speakers, Rogers LS3/5a, Martin Logan Request, and about 10 tube amps, mostly 300b, and EL34 and 1 KT66 amp. |
