Alexberger wrote: " Back of ceiling firing tweeters sound horrible!!! It completely destroys focus and sound-stage."
I disagree. Quite the contrary in fact when done right, and I can go into detail if you’d like.
The reason for keeping the supertweeter out of the first-arrival sound is so that it doesn’t screw up the phase of that first-arrival sound coming from your fullrange driver.
By increasing the amount of high-frequency energy in the reverberant field while leaving the first-arrival sound intact, you are fixing the tonal balance without degrading anything else, as long as the reflection path length is long enough. And a ceiling bounce usually is long enough at high frequencies.
Regarding whether or not to use a resistor or an L-pad, again that’s "play it by ear". DO NOT put an L-pad or any parallel resistor (or inductor) legs AHEAD of the crossover capacitor. Any resistor (or inductor) leg in parallel with any driver’s coil NEEDS the crossover capacitor in between it and the amplifier to filter out the rest of the signal, otherwise your resistor (or inductor) leg is seeing a full-power, full-spectrum signal from the amplifier.
If your crossover (more precisely, high-pass filter) is first order - i.e. just a capacitor - and if you’re just using a series resistor to adjust the level, then it does not matter whether you place that resistor before the capacitor or after the capacitor. Either way, the resistance that the capacitor "sees" is the supertweeter + the resistor.
Duke
I disagree. Quite the contrary in fact when done right, and I can go into detail if you’d like.
The reason for keeping the supertweeter out of the first-arrival sound is so that it doesn’t screw up the phase of that first-arrival sound coming from your fullrange driver.
By increasing the amount of high-frequency energy in the reverberant field while leaving the first-arrival sound intact, you are fixing the tonal balance without degrading anything else, as long as the reflection path length is long enough. And a ceiling bounce usually is long enough at high frequencies.
Regarding whether or not to use a resistor or an L-pad, again that’s "play it by ear". DO NOT put an L-pad or any parallel resistor (or inductor) legs AHEAD of the crossover capacitor. Any resistor (or inductor) leg in parallel with any driver’s coil NEEDS the crossover capacitor in between it and the amplifier to filter out the rest of the signal, otherwise your resistor (or inductor) leg is seeing a full-power, full-spectrum signal from the amplifier.
If your crossover (more precisely, high-pass filter) is first order - i.e. just a capacitor - and if you’re just using a series resistor to adjust the level, then it does not matter whether you place that resistor before the capacitor or after the capacitor. Either way, the resistance that the capacitor "sees" is the supertweeter + the resistor.
Duke