After having bought a pair of SEAS 27TBCD/GB-DXT tweeters, I used them temporarily as drop-in replacements for some old speakers and removed them before selling the old boxes off..
After having read a lot lately about X-over frequency, dispersion (or power distribution, etc.. I've gotten a renewed interest in these tweeters..
I have buildt a pair of 12L closed boxes with SEAS W17cy-001 midwoofers and Peerless DT-104 tweeters. all in a temproary passive X-over set up awaiting axctive x-over and full amping.
The goal is to cross the midwoofers over as high as possible, so as to leave as much as possible of the critical midrange area undisturbed.
Frequency wise, the midranges should be capable of extending to 3-4kHz, but the laws of physics being what they are, dispersion will start to narrow at these frequencies.
In it self not necessarily a problem, perhaps the contrary, a limited dispersion will give less early reflections from nearby surfaces, and early reflection is unarguably detrimental to stereo imaging.
It then stands to reason that when crossing over to a tweeter, which again has very wide dispersion in this frequency range, the transition can not become as smooth as hoped for.
It was with great interest I once read something by a Dr. E. Geddes where he argues the use of relatively large midwoofers as a means of intentionally narrowing the dispersion and then using waveguides for the tweeters in order to match the dispersion pattern in the x-over region.
further to this, reading about John Krutkes wave-guide experimentation was also very interesting allthough his intended ends seemed to be more towards lower X-over frequency and reduction of HD.
Obviously, the wave-guide (or DXT lens) of the DXT tweeters will not be effective for dispersion control to as low frequencies as the 6" waveguides used by John, not to mention the even larger guides discussed by Dr. E. Geddes.
Then again, that might not necessarily be a big problem as my goal was a relatively high X-over..
Now the problem is, how do Identify the frequency where the dispersion pattern of the DXT tweeters and the SEAS W17CY's have the best match??
Anny suggestions towards this, or any other relevant comments and advice will of course be greatly appreciated!
After having read a lot lately about X-over frequency, dispersion (or power distribution, etc.. I've gotten a renewed interest in these tweeters..
I have buildt a pair of 12L closed boxes with SEAS W17cy-001 midwoofers and Peerless DT-104 tweeters. all in a temproary passive X-over set up awaiting axctive x-over and full amping.
The goal is to cross the midwoofers over as high as possible, so as to leave as much as possible of the critical midrange area undisturbed.
Frequency wise, the midranges should be capable of extending to 3-4kHz, but the laws of physics being what they are, dispersion will start to narrow at these frequencies.
In it self not necessarily a problem, perhaps the contrary, a limited dispersion will give less early reflections from nearby surfaces, and early reflection is unarguably detrimental to stereo imaging.
It then stands to reason that when crossing over to a tweeter, which again has very wide dispersion in this frequency range, the transition can not become as smooth as hoped for.
It was with great interest I once read something by a Dr. E. Geddes where he argues the use of relatively large midwoofers as a means of intentionally narrowing the dispersion and then using waveguides for the tweeters in order to match the dispersion pattern in the x-over region.
further to this, reading about John Krutkes wave-guide experimentation was also very interesting allthough his intended ends seemed to be more towards lower X-over frequency and reduction of HD.
Obviously, the wave-guide (or DXT lens) of the DXT tweeters will not be effective for dispersion control to as low frequencies as the 6" waveguides used by John, not to mention the even larger guides discussed by Dr. E. Geddes.
Then again, that might not necessarily be a big problem as my goal was a relatively high X-over..
Now the problem is, how do Identify the frequency where the dispersion pattern of the DXT tweeters and the SEAS W17CY's have the best match??
Anny suggestions towards this, or any other relevant comments and advice will of course be greatly appreciated!
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