A fast way to build a CBT
I couldn´t get my mind off of building a line array of the E60´s.
With the experience of building the design above, I realized that it would be easy to build CBTs:
I´m trying burlap to get rid of some of the hf intermodulation.
Kanthal thread supplied the shading from 0 to 32 ohms.
I then got this frequency response in sweet spot:
A curve fairly easy to adjust with Frequency Allocator.
I couldn´t get my mind off of building a line array of the E60´s.
With the experience of building the design above, I realized that it would be easy to build CBTs:
I´m trying burlap to get rid of some of the hf intermodulation.
Kanthal thread supplied the shading from 0 to 32 ohms.
I then got this frequency response in sweet spot:
A curve fairly easy to adjust with Frequency Allocator.
So the line array is acting as a line source from 500 Hz, hence the 6 dB rise.
Hf cancellation kicks in at 3 kHz, despite the CBT and burlap, with a 6 dB/octave slope.
So the eq is bringing down 500 Hz to 3 kHz 6 dBs and then there´s a 6 dB/octave rise from 5 kHz.
XO is set to 250 Hz.
Any suggestions for another diffractor material than burlap?
Hf cancellation kicks in at 3 kHz, despite the CBT and burlap, with a 6 dB/octave slope.
So the eq is bringing down 500 Hz to 3 kHz 6 dBs and then there´s a 6 dB/octave rise from 5 kHz.
XO is set to 250 Hz.
Any suggestions for another diffractor material than burlap?
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FAST goes FA
I went to a concert the other night; Zappa plays Zappa. It was awesome, but I also focused on the PA. Up in the ceiling there were some CBTs...
Of course, that makes perfectly sense, as I was sitting in the third row to the left right in front of Sheila, I was subjected to the shaded bottom J of the CBTs. People far back were given the unshaded SPL from the CBTs.
So why do I have them in my listening room, sitting in the same sweet spot?
And why do I think that having multiple, all different in time, soundwaves will sound good?
Thanks to norman bates and Melo Theory and their patient answers to my questions in their threads, I'm now convinced that focused arrays(FA) is the way to go. Again, thank you guys!
I´ll be re-using all the components I have so far. Well except for the burlap and the Kanthal wire of course. The contraption will be almost the same, this time the curve will be concave and uniform.
I went to a concert the other night; Zappa plays Zappa. It was awesome, but I also focused on the PA. Up in the ceiling there were some CBTs...
Of course, that makes perfectly sense, as I was sitting in the third row to the left right in front of Sheila, I was subjected to the shaded bottom J of the CBTs. People far back were given the unshaded SPL from the CBTs.
So why do I have them in my listening room, sitting in the same sweet spot?
And why do I think that having multiple, all different in time, soundwaves will sound good?
Thanks to norman bates and Melo Theory and their patient answers to my questions in their threads, I'm now convinced that focused arrays(FA) is the way to go. Again, thank you guys!
I´ll be re-using all the components I have so far. Well except for the burlap and the Kanthal wire of course. The contraption will be almost the same, this time the curve will be concave and uniform.
A concert i'd really like to see. Frank said Dwezil was a better guitar player than he was.
dave
Might have been the proud poppa syndrome, but D. Zappa is no slouch.
High praise indeed!
Don
Got focused
So I managed to build a couple of FAs:
From this angle nothing seems to have changed, but instead of CBTs it is now concave focused arrays.
Measurement from sweet spot:
Red curve is somewhat 20 dB higher in reality, the elements are couple 4 and 4 in parallell and then in series.
Blue curve with resistors (120 ohm was what I could get on a Sunday afternoon) in series with each element.
All the elements plus their resistor is then coupled in parallell.
I will mount 56 ohm instead of the 120 when I get them.
The humps at 150 Hz, 650 Hz and 1500 Hz are candidates for some EQ:ing;
XO will probably be at 250 Hz so I don't bother with the one at 140 Hz.
So any comments on the two curves?
So I managed to build a couple of FAs:
From this angle nothing seems to have changed, but instead of CBTs it is now concave focused arrays.
Measurement from sweet spot:
Red curve is somewhat 20 dB higher in reality, the elements are couple 4 and 4 in parallell and then in series.
Blue curve with resistors (120 ohm was what I could get on a Sunday afternoon) in series with each element.
All the elements plus their resistor is then coupled in parallell.
I will mount 56 ohm instead of the 120 when I get them.
The humps at 150 Hz, 650 Hz and 1500 Hz are candidates for some EQ:ing;
XO will probably be at 250 Hz so I don't bother with the one at 140 Hz.
So any comments on the two curves?
It was very hard to get the CBTs integrated with the woofers, it was just a bass blur around the XO. Above the XO, the sound wasn't great either.
So having multiple identical sound information arriving with different timing to your sweet spot isn't a great idea; I don't understand why one should want to have CBTs in a home environment.
The FA setup, however, is giving my dipole ribbons a real match. Waving my head around didn't produce any awkwardness either. So perhaps the sweet spot isn´t that small.
I just finished replacing the 120 ohm series resistors with 56 ohm and have also done some paint job and haven't had the time yet to really listen to the FAs.
I haven't done serious EQ-ing either, so I have to come back with some feedback.
So having multiple identical sound information arriving with different timing to your sweet spot isn't a great idea; I don't understand why one should want to have CBTs in a home environment.
The FA setup, however, is giving my dipole ribbons a real match. Waving my head around didn't produce any awkwardness either. So perhaps the sweet spot isn´t that small.
I just finished replacing the 120 ohm series resistors with 56 ohm and have also done some paint job and haven't had the time yet to really listen to the FAs.
I haven't done serious EQ-ing either, so I have to come back with some feedback.
Painted the FAs black to match my subs:
Finally did the EQ:ing. Looking at the blue curve in the post above, I never understood the dip around 1 kHz. Does anyone have a teory?
Anyway, everything is there: soundstage, lows and highs, you name it.
This will be my setup for a while, at least over the holidays
Next project will be to make five HT satellites out the 18 E60s I got left.
I'll be doing the fast way, so they might turn up in this thread as well.
Finally did the EQ:ing. Looking at the blue curve in the post above, I never understood the dip around 1 kHz. Does anyone have a teory?
Anyway, everything is there: soundstage, lows and highs, you name it.
This will be my setup for a while, at least over the holidays
Next project will be to make five HT satellites out the 18 E60s I got left.
I'll be doing the fast way, so they might turn up in this thread as well.
Melo Theory actually inspired me in the first place.
Mine's got an open back though, that is they are dipoles.
Mine's got an open back though, that is they are dipoles.
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