Hello,
here is Natural, a design principle for a quite loud and beaming but neither too big nor too expensive (electric parts wise) active two-way loudspeaker with a phase turn of either 0 or Pi somewhere thru the lower half of audible frequency range. Natural is Synergy plus better horn plus finer woofer mesh minus sound compression minus DSP. It consists of
* a highpass made of a horn driven by one broad-range driver
* a lowpass consisting of four or eight direct-radiating woofers
* a line-level crossover
* a power amplifier for each pass.
Regarding the horn, as sound shall not become compressed, diaphragm size is given by, how much dispersion is needed at upper limit frequency. A rudimentary phase plug, for example a plaster egg in front of a 6 1/2 inch driver, raises output at his frequency. Contour and size of the horn determine beaming at lower frequencies. I suggest a contour of arithmetic mean of conical and exponential, balancing acoustic loading and flat beamwidth.
Driver needs to come with high treble efficiency, also look at electrical impedance. For thermal protection I use medium-fast-acting wire fuses, they are well suited and simple.
Woofers are sat at horn perimeter or some way into it but fully open, not behind a port. In order to be able to mount the woofers as close together as possible and to reduce distance between adjacent woofers, one uses many woofers.
I use a hipass of first and a lopass of second order. First order for good time response: With the run-time due to the horn, the sum shall have good pulse response. Second order for dampening of lobes: As the horn beams rather narrowly, woofers must not spoil that off-axis silence.
One may also use a cascade of allpasses for electrically adjusting sound travel time. Allpass of first order with operational amplifier:
SourceVoltage-2R-NegativeInput-2R-OutputVoltage
SourceVoltage-R-(PositiveInput|C)
This causes a frequency(phase turn of Pi/2) = 1/2PiRC and a time delay below that frequency of t(delay)=RC/Pi.
Uli
here is Natural, a design principle for a quite loud and beaming but neither too big nor too expensive (electric parts wise) active two-way loudspeaker with a phase turn of either 0 or Pi somewhere thru the lower half of audible frequency range. Natural is Synergy plus better horn plus finer woofer mesh minus sound compression minus DSP. It consists of
* a highpass made of a horn driven by one broad-range driver
* a lowpass consisting of four or eight direct-radiating woofers
* a line-level crossover
* a power amplifier for each pass.
Regarding the horn, as sound shall not become compressed, diaphragm size is given by, how much dispersion is needed at upper limit frequency. A rudimentary phase plug, for example a plaster egg in front of a 6 1/2 inch driver, raises output at his frequency. Contour and size of the horn determine beaming at lower frequencies. I suggest a contour of arithmetic mean of conical and exponential, balancing acoustic loading and flat beamwidth.
Driver needs to come with high treble efficiency, also look at electrical impedance. For thermal protection I use medium-fast-acting wire fuses, they are well suited and simple.
Woofers are sat at horn perimeter or some way into it but fully open, not behind a port. In order to be able to mount the woofers as close together as possible and to reduce distance between adjacent woofers, one uses many woofers.
I use a hipass of first and a lopass of second order. First order for good time response: With the run-time due to the horn, the sum shall have good pulse response. Second order for dampening of lobes: As the horn beams rather narrowly, woofers must not spoil that off-axis silence.
One may also use a cascade of allpasses for electrically adjusting sound travel time. Allpass of first order with operational amplifier:
SourceVoltage-2R-NegativeInput-2R-OutputVoltage
SourceVoltage-R-(PositiveInput|C)
This causes a frequency(phase turn of Pi/2) = 1/2PiRC and a time delay below that frequency of t(delay)=RC/Pi.
Uli
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