Summary Martagon tri-way equalization
Indeed, what exactly are we looking for with our last discussions...
This is an attempt to summarize.
Please consider the below picture showing dB versus frequency for a tri-way loudspeaker, schematically.
The 3 'dashed' BLACK lines indicate the sensitivities of the 15 inch LF, the 8 inch MF and the Fostex HF horn used in the Martagon SuperSize.
!! Sensitivity is a function of frequency; manufacturers typically pump out ONE figure that represents the mean value over the frequency band (at 1 mtr and noise excitation at 2.83 Volt RMS).
The RED line indicates the LF unit in the 'raw' LF Horn.
Typically, the hybrid truncated LFhorn shows a 'lineair' increase with frequency from 20 - 100 Hz, over this range the mean 'Gain' is 9 dB; we discussed this behaviour before.
The mean sensitivity over this range is around 103 dB. Without DSP equalizing, the raw horn pumps out a brute earth-quaking punchy bass, but not exactly HiFi of course, but stilll very 'fast-responding' and 'dry'.
The GREEN line indicates the LF Horn with some DSP (see earlier in these communications)' The flat response has a mean sensitivity of 101 dB.
The sound now is definitively 'HiFi', less 'brute', but with a distinguised 'dry' and 'fast' character. Drum-kick and bass(guitar) are completey separated, also at the beginning of the 'kick': NICE / 'heavenly' for a bassplayer....
The BLUE lin 'LF +2 dB Gain' shows the final setting for the LF unit at 103 dB to equalize with the mid and high (see below).
The BLUE line 'MF Horn + DSP equalizing' shows the final setting for the MF driver; the residual mean 'Gain' of the horn is around 7 dB.
The BLUE line 'HF - 2 dB Gain' indicates the final setting of the HF horn with its sensitivity attenuated down to 103 dB
At last: the tri-way components are ADDED / fed to the 3 amps with the various delays of the 3 impulse responsed incorporated to yield linear phase.
Indeed, I do not have the tools (and room) to measure absolute dB values. So the reasoning here is backwards, from the KNOWN sensitivity of the Fostex. Fair enough for me, for this moment.
Cheers
Indeed, what exactly are we looking for with our last discussions...
This is an attempt to summarize.
Please consider the below picture showing dB versus frequency for a tri-way loudspeaker, schematically.
The 3 'dashed' BLACK lines indicate the sensitivities of the 15 inch LF, the 8 inch MF and the Fostex HF horn used in the Martagon SuperSize.
!! Sensitivity is a function of frequency; manufacturers typically pump out ONE figure that represents the mean value over the frequency band (at 1 mtr and noise excitation at 2.83 Volt RMS).
The RED line indicates the LF unit in the 'raw' LF Horn.
Typically, the hybrid truncated LFhorn shows a 'lineair' increase with frequency from 20 - 100 Hz, over this range the mean 'Gain' is 9 dB; we discussed this behaviour before.
The mean sensitivity over this range is around 103 dB. Without DSP equalizing, the raw horn pumps out a brute earth-quaking punchy bass, but not exactly HiFi of course, but stilll very 'fast-responding' and 'dry'.
The GREEN line indicates the LF Horn with some DSP (see earlier in these communications)' The flat response has a mean sensitivity of 101 dB.
The sound now is definitively 'HiFi', less 'brute', but with a distinguised 'dry' and 'fast' character. Drum-kick and bass(guitar) are completey separated, also at the beginning of the 'kick': NICE / 'heavenly' for a bassplayer....
The BLUE lin 'LF +2 dB Gain' shows the final setting for the LF unit at 103 dB to equalize with the mid and high (see below).
The BLUE line 'MF Horn + DSP equalizing' shows the final setting for the MF driver; the residual mean 'Gain' of the horn is around 7 dB.
The BLUE line 'HF - 2 dB Gain' indicates the final setting of the HF horn with its sensitivity attenuated down to 103 dB
At last: the tri-way components are ADDED / fed to the 3 amps with the various delays of the 3 impulse responsed incorporated to yield linear phase.
Indeed, I do not have the tools (and room) to measure absolute dB values. So the reasoning here is backwards, from the KNOWN sensitivity of the Fostex. Fair enough for me, for this moment.
Cheers
Yes Wim, very clear and well documented. 
I see your point about reasoning backwards from the Fostex horn, as long as the amps and DCX channels are all set to the same gain. That's important, as you know.
The only way to know for sure is to measure pink noise at the speaker terminals with a good averaging meter, then measure the SPL at 1 meter.
I see your point about reasoning backwards from the Fostex horn, as long as the amps and DCX channels are all set to the same gain. That's important, as you know.
- The bass signal is attenuated by 4dB average across its bandwidth
- The tweeter signal is attenuated by 2dB
- Bass signal then raised by 2dB to match tweeter (bass now at -2dB)
- Bass and tweeter have same sensitivity, after bass EQ.
The only way to know for sure is to measure pink noise at the speaker terminals with a good averaging meter, then measure the SPL at 1 meter.
Martagon tri-way EQ
yes, you got it all right!
At this point, I do not have the right equipment, and, at such low frequencies, even if you go outside, there is always influence of floor-reflections and such.
For now, I am happy.
This brings me to some previous remarks where it is stated that there is 'low efficiency' at the LF.
? That suprises me: > 101 dB from 28 Hz on, and with flat response, lineair phase and very low HD, that sounds impressive to me (also literally...).
Add, that the LF can handle up to 1000 Watt peak, this sums up to 101 + 30 dB (with some 2 dB compression loss)= 129 dB.
I do know that in the PA industry there are multi-woofer (2 x 18 inch or 2 x 21 inch) 6th order bandpass monsters that can handle 3000 Watt and pump out 136 dB (theoretically), but that is another ballgame over high-end HiFi and in-home or smaller venues application.
Having said that, imagine what a 4-stacked Martagon can deliver: thanks to the acoustic coupling of 4 horn-mouths, this would approach 140 dB....; also, because the mean frequency of such multi-horn shifts downwards, the EQ attenuation/loss of 4 dB on average will be less.
L.O.L.... (but were to find funding to build, .. haha)
yes, you got it all right!
At this point, I do not have the right equipment, and, at such low frequencies, even if you go outside, there is always influence of floor-reflections and such.
For now, I am happy.
This brings me to some previous remarks where it is stated that there is 'low efficiency' at the LF.
? That suprises me: > 101 dB from 28 Hz on, and with flat response, lineair phase and very low HD, that sounds impressive to me (also literally...).
Add, that the LF can handle up to 1000 Watt peak, this sums up to 101 + 30 dB (with some 2 dB compression loss)= 129 dB.
I do know that in the PA industry there are multi-woofer (2 x 18 inch or 2 x 21 inch) 6th order bandpass monsters that can handle 3000 Watt and pump out 136 dB (theoretically), but that is another ballgame over high-end HiFi and in-home or smaller venues application.
Having said that, imagine what a 4-stacked Martagon can deliver: thanks to the acoustic coupling of 4 horn-mouths, this would approach 140 dB....; also, because the mean frequency of such multi-horn shifts downwards, the EQ attenuation/loss of 4 dB on average will be less.
L.O.L.... (but were to find funding to build, .. haha)
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