Replacing my tweeters a good idea?


I have a pair of infinity Delta 70 loudspeakers. They have 2x8" 1 6" 1 4" and a metal tweeter. They image superbly, and set a good soundstage. People think infinity are bad, but they are great in my ears, apart from the metal dome tweeter. It gets a bit harsh on some recordings. Is it possible that i could replace the tweeters with something else, say dynaudio tweeters? would it be worht the trouble? I am not getting new speakers.. so dont bother trying to say that. :P thanks
shabbadoo
Just splice the resistor into one of the leads to the tweeter; positive or negative won't matter. You could use an 8 ohm pot temporarily to get the exact value you like, then buy a fixed resistor of that value. If you still can't get it right I'll sell you my nice pair of 19mm Seas plastic-dome tweeters cheap. (I'm through with speaker building!) Good Luck.
Yo Shabbadoo, I doubt that you can find a replacement for the EMIT tweeter that will sound half as good. They really are superior to most of the dome tweeters out there. That EMIT tweeter is just complaining about the cheap capacitor Infinity used in the crossover. Try bypassing the last cap (closest to the tweeter) in the crossover with a Crescendo cap of a .1 mf value ($7.45 ea.). Solder it in parallel with the existing cap. Or if you feel flush replace it with the same value in a cascade bypass arrangement. Read all about it at: http://www.northcreekmusic.com/Bypassing.html. By all means discuss the idea with George at North Creek before you try inserting resistors in series with the EMITs. The other thing that will help is if you treat the room with acoustic foam treatments to minimize early reflections off of the side walls, front and back walls and ESPECIALLY THE UPPER CORNERS.
While i hope that nobody takes this personally, but "just inserting" a resistor into a speaker circuit is NOT a good idea. Outside of lowering the output level, it will alter the crossover frequency, change damping and tonal characteristics, etc... The ENGINEERS at Infinity didn't just throw parts into a box and hope that it worked out okay. Nonetheless, there is always room for improvement in any design though and this is especially true of mass market brands and speakers in specific. Your best bet is to look elsewhere in the chain to see what may be aggravating the problem. As someone mentioned, the use of low grade crossover components INSIDE the speaker may also be causing problems. You really have to look at the system AS A SYSTEM and NOT cast the blame on just one component. Unless you have changed things around enough and substituted other components in their places, you can't be sure exactly what is causing the problem. You might be surprised at what can cause "less than stellar" performance out of a system. My suggestion is to look at the source components and then work your way back. Is the problem only with one source ( cd's ) or when listening to any source ? This will give you an idea as to whether the problem is SYSTEM based or COMPONENT based. From there, the path to take will be much clearer. Sean >
Sean, you are partially correct about what happens when a resistor is inserted into the speaker circuit. Output is lowered, tonal characteristics are changed. THAT IS THE POINT!!! Crossover frequency is left UNAFFECTED by resistors. Resistors merely attenuate the output. Here we want to tame a bright speaker. MANY, if not most speaker companies wire a 1 to 3 ohm speaker in series with the tweeter, on purpose. They want the speaker to be 3 db down at 15K. Why? Because most people complain the same speaker without that resistor is too bright. Crossover frequency IS determined by capacitors AND inductors. A capacitor in series limits a lower frequency being passed to a driver. And inductor in series limits a higher frequency being passed to a driver. A first order crossover has a capacitor on the positive side on the tweeter leg, and an inductor on the positive side of the woofer leg. If you had a midrange, it would have both a capacitor and an inductor in series(again, on the positive side) with that driver. Rolloff would be 6 db/octave, depending on the component values used. Adding an inductor in parallel to the tweeter, and a capacitor in parallel to the woofer(and both in parallel to the midrange) is a second order crossover(12 db/octave), and so on. Alternating these components in series and in parallel(maybe confusing, but no need to explain in detail here) takes us up to 4th order(normally). Resistors don't factor into this crossover equation AT ALL. Their purpose. To attenuate drivers. Say a tweeter with 91 db/2.83 V sensitivity is used in a speaker with an 89 db/2.83 V sensitive woofer. The tweeter needs to be quieted down a bit(we can't increase the woofer output), for the speaker to be balanced(I still listen before inserting the resistor - just to get a baseline feel). We may also need other things in the circuit(won't discuss them here), but they come later.