I have a bunch of 3/4" MDF left over from making my FleXy Table. I purchased two CTS KSN-1005A piezo tweeters, two 20 ohm 20 watt resistors, pairs of a variety of caps 1.0uF, 0.68uF, 0.47uF, 0.33uF, 0.22uF, and 0.10uF, 4 ounces of Dammar varnish, and some ACE Hardware rope caulk. Well, after some research (Thanks Godzilla!) I am ready to try my experiment. I'm glad I'm actually getting helpful information and support from other quarters. If the piezo driver is straight line attenuated, which is the way I am now leaning, there is no roll-off below the crossover point.īesides I have nothing better to do than play around with this to see what happens. This is mostly marketing, but there is substantial evidence that there are psychoacoustic benefits to loudspeakers which extend beyond the upper frequncies of human perception and some support to the idea that a system that can go beyond what frequencies can be perceived will do a better job with those frequencies that can be. However, that does not stop loudspeaker manufacturers from creating products that extend above 20 kHz, some to 40 kHz. I think most people are well aware that while 20 kHz is considered the audible limit for humans that most with age people cannot hear frequencies above 16 kHz. There are other examples of DIY loudspeakers that have successfully used the piezo and achieved good sound, particularly as an accessory to full range drivers.Ģ. The KSN-1005 piezo (not the cheap knock offs) with modifications can be a pleasant, non-fatiguing driver to add some air or presence to the high frequency output of a speaker with relatively little in the way of circuitry. The piezo was used as a super tweeter to extend the high frequency range beyond what the tweeter provided. The Dahlquist DQ-10 is a decent sounding vintage loudspeaker with a substantial following. 22uF capacitor.įor straight level attenuation a simple non-polar capacitor can be wired in series after a 50 ohm, 2 watt resistor wired in series is established to eliminate ultrasonic resonance interaction between the tweeter and amp.Įither way, I'm just trying to figure out what the value of the capacitor must be to acheive the 17 kHz cutoff. Then I assumed it is a matter of establishing an 8 ohm 12 dB filter for cutoff at 17 kHz with a. This can be done by wiring an 8 ohm resistor across the piezo tweeter. Not having a command of crossover networks I am just trying to devise a simple circuit to attenuate frequencies below 17 kHz.įor a conventional crossover the piezo tweeter must be made to look "resistive" in order to work with the crossover. The Large Advent does fine to 17 kHz, I would like to experiment with something that would take it higher from there. When one has 6 pairs of Large Advents a few it would seem would be open for some experimentation. The Dahlquist DQ-10 is about as classic a loudspeaker as it gets and it uses the KSN-1005 as a super tweeter. 22uF capacitor will provide a 17 kHz rolloff for an 8 ohm 12 dB filter? 47uF capacitor will provide a 15 kHz rolloff at 8 ohms. 22uF capacitor wired in series the correct device to get a 17 kHz rolloff as a 12 dB filter at 8 ohms? From the 2nd order crossover charts I have seen, a. Even though this will limit the output of the piezo somewhat that will probably be OK as the piezo is much more efficient than the Large Advent system. I will be making the piezo appear as an 8 ohm driver with an 8 ohm/20 watt resistor. I'm attempting to get frequencies about 17 kHz and above passed to the piezo. I want to incorporate a CTS KSN-1005 piezo into a New Large Advent speaker. An application of rope caulk to the back and sides of the horn helps to deaden any plastic sound. Remove the three screws from the back of the piezoī.Coat the paper cone with one coat of damarĬ.Remove ‘pooling’ of damar with a tissueĤ. Application of damar varnish on the piezo’s cone element is said to add refinement to the sound and almost completely reduce the fatiging sibilance:Ī. 0.47 uf capacitor wired in series (Hovland, $1.50 each from Madisound) I assume this only allows frequencies above 15,000 Hz (based on 12dB filter parameters) go to the piezo tweeter.ģ. 8 ohm/20 watt resistor across the piezo terminals (Radio Shack part # 271-120, $1.49 each) This resistor makes the piezo appear to the system as an 8 ohm driver?Ģ. Although no crossover is needed and this driver supposedly does not significantly affect the impedence of the speaker it is wired to, I found the following ‘crossover’ circuit and modifications to the driver that is said to eliminate its "spitty and lispy" fatiguing harshness:ġ. I thought I might try to extend the high frequency of the Large Advent by adding a Radio Shack Piezo Tweeter 40-1218 or the Motorola/CTS KSN-1005 (4kHz-27kHz). The New Large Advent loudspeaker has a reported frequency response of 33Hz to 17,000Hz +/- 3dB.
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