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Since I've recently started using a pair of these I figured I might as well post some measurements.
Note all distortion and fr graphs were taken with a 40uf cap in series with the driver. Although the risk is small I don't enjoy connecting tweeters directly up to amplifiers.
First up the frequency response on my baffle. This is 25cm wide and 48cm tall with the tweeter mounted at the top and slightly off centre.
Very smooth performance. The off axis plots weren't measured to any specific degree, but rather show a decent range of angles out to around 60 degrees.
Next up a distortion plot taken at just below 2.8 volts RMS.
Again excellent overall performance, especially low 2nd order and low 3rd order over 3k. The spike in the 3rd order @ 8.5khz is down to cone resonance amplification due to the rigid diaphragm, this isn't a problem, the 3rd harmonic of this spike is the resonance peak @ ~25khz and we can't hear it.
The system I wished to incorporate the tweeter into uses and active crossover, however it doesn't include a resonance trap. No matter what fiddling I did with the 4th order electrical high pass I couldn't get it to fit to anything acceptable so I had to resort to a passive filter. This isn't a problem for me anyway, I always include a cap in series with the tweeter, so adding a few more components wasn't a concern.
With the values I had on hand I came up with this.
Fairly standard values and it creates a frequency response that is easily shape-able into anything reasonable.
How does the tweeter sound? Excellent in my opinion and smoother then any soft dome I've ever used. The off axis response really is remarkable. I sit in two different main listening positions, one ~2 meters away from the loudspeakers for critical listening and another around 80cm from them. Sitting closer obviously increases the angle that I am at with respect to the tweeter. With the old vifa XT25 there was a huge shift in the way it sounded in the different positions, however with the DXT there's virtually none.
Considering the price I really can't fault the tweeter. The only concern might be if you need a really sensitive tweeter. After you've compensated for the hump created by the wave-guide you're down to around 87dB. The off axis response is where this tweeter really shines and apart from the large standard 104mm cut-out, I can see this tweeter making a lot of sense in centre channels and possible surround channels although I'm not sure what the requirements are for those.
Last I've included a distortion plot of the system from 500hz-20khz. This is at between 25-35 volts peak to peak as measured from the tweeter. As this is an active system there isn't any loudspeaker side attenuation, so the drive level varies for the differing sensitivities of the drivers. This should roughly correspond to an SPL @ 1 meter of around 100dB. This is LOUD and louder then I would ever listen to it. The midrange driver is a W15CY001. Crossover 4th order @ 2khz.
The drive level increases towards high frequencies, which is probably where the increase beyond 10k is coming from. Yes the driven load does become harder towards 10k, but the increase in amplifier distortion because of this should be negligible.
Amp distortion @ full power (100 watts) into a 9.4 ohm load.
One thing to mention is that things in the room rattle when performing this sweep so there are some peaks in the distortion plot related to this rather then the loudspeakers themselves.
Note all distortion and fr graphs were taken with a 40uf cap in series with the driver. Although the risk is small I don't enjoy connecting tweeters directly up to amplifiers.
First up the frequency response on my baffle. This is 25cm wide and 48cm tall with the tweeter mounted at the top and slightly off centre.
Very smooth performance. The off axis plots weren't measured to any specific degree, but rather show a decent range of angles out to around 60 degrees.
Next up a distortion plot taken at just below 2.8 volts RMS.
Again excellent overall performance, especially low 2nd order and low 3rd order over 3k. The spike in the 3rd order @ 8.5khz is down to cone resonance amplification due to the rigid diaphragm, this isn't a problem, the 3rd harmonic of this spike is the resonance peak @ ~25khz and we can't hear it.
The system I wished to incorporate the tweeter into uses and active crossover, however it doesn't include a resonance trap. No matter what fiddling I did with the 4th order electrical high pass I couldn't get it to fit to anything acceptable so I had to resort to a passive filter. This isn't a problem for me anyway, I always include a cap in series with the tweeter, so adding a few more components wasn't a concern.
With the values I had on hand I came up with this.
Fairly standard values and it creates a frequency response that is easily shape-able into anything reasonable.
How does the tweeter sound? Excellent in my opinion and smoother then any soft dome I've ever used. The off axis response really is remarkable. I sit in two different main listening positions, one ~2 meters away from the loudspeakers for critical listening and another around 80cm from them. Sitting closer obviously increases the angle that I am at with respect to the tweeter. With the old vifa XT25 there was a huge shift in the way it sounded in the different positions, however with the DXT there's virtually none.
Considering the price I really can't fault the tweeter. The only concern might be if you need a really sensitive tweeter. After you've compensated for the hump created by the wave-guide you're down to around 87dB. The off axis response is where this tweeter really shines and apart from the large standard 104mm cut-out, I can see this tweeter making a lot of sense in centre channels and possible surround channels although I'm not sure what the requirements are for those.
Last I've included a distortion plot of the system from 500hz-20khz. This is at between 25-35 volts peak to peak as measured from the tweeter. As this is an active system there isn't any loudspeaker side attenuation, so the drive level varies for the differing sensitivities of the drivers. This should roughly correspond to an SPL @ 1 meter of around 100dB. This is LOUD and louder then I would ever listen to it. The midrange driver is a W15CY001. Crossover 4th order @ 2khz.
The drive level increases towards high frequencies, which is probably where the increase beyond 10k is coming from. Yes the driven load does become harder towards 10k, but the increase in amplifier distortion because of this should be negligible.
Amp distortion @ full power (100 watts) into a 9.4 ohm load.
One thing to mention is that things in the room rattle when performing this sweep so there are some peaks in the distortion plot related to this rather then the loudspeakers themselves.
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