Just to share very nice results of T34B plus 7" custom waveguide combination. Today I measured horizontal responses 0-90deg. I could not wish better results. Measurement was done in 2way cabinet with rounded edges to smooth out the responses as much as possible, mic distance 70cm, and gatting 4ms. My mic is calibrated to 25kHz.
This combo is planned for large 3way project with 18WE as midrange and 32W/4878T00 in sealed cabinet. Fully active, alldriven by OctoDAC with implemented miniSharc and 3 stereo power amps BV PA300SSE.
This combo is planned for large 3way project with 18WE as midrange and 32W/4878T00 in sealed cabinet. Fully active, alldriven by OctoDAC with implemented miniSharc and 3 stereo power amps BV PA300SSE.
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mbrennwa: I was very careful when removing the grill and during whole mounting to WG. I do not feel much comfortable to leave the dome exposed like that, so fabric grills will be made, to cover whole baffle. As WG is made out of alloy, I am thinking of making some protective elemets similar to Satori Be tweeters, or to use original T34B grills and attach them to waveguides.
I added also Vituix graphs, power response and DI.
As I already know the sound of T25B, and I like it very much, I cannot wait to listen to this combo.
I added also Vituix graphs, power response and DI.
As I already know the sound of T25B, and I like it very much, I cannot wait to listen to this combo.
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T34B + WG:
- at 2kHz 0-60deg SPL difference is -4dB
From my measurements of 18WU, there is -5.8dB difference. Datasheet value is -5dB.
From datasheet, 18WE has that difference -4dB. So in baffle I expect ~-5dB.
So for frequencies around 2kHz directivities of 18WE and T34B WG are well matched. I will try to make crossover frequency ~1500Hz, maybe even lower.
- at 2kHz 0-60deg SPL difference is -4dB
From my measurements of 18WU, there is -5.8dB difference. Datasheet value is -5dB.
From datasheet, 18WE has that difference -4dB. So in baffle I expect ~-5dB.
So for frequencies around 2kHz directivities of 18WE and T34B WG are well matched. I will try to make crossover frequency ~1500Hz, maybe even lower.
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Nice graphs continue.......
Today I took SPL calibrated measurement and impedance measurement, and tried to model LR4 crossover at 1500Hz and 85dB. So far it looks promising and easy to work with.
As midrange driver runs into waveguide partially, and was not properly flush mounted, I expect irregularities around 10kH to smooth out a little when midrange is installed properly.
Today I took SPL calibrated measurement and impedance measurement, and tried to model LR4 crossover at 1500Hz and 85dB. So far it looks promising and easy to work with.
As midrange driver runs into waveguide partially, and was not properly flush mounted, I expect irregularities around 10kH to smooth out a little when midrange is installed properly.
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It is somewhat rare for a tweeter circuit to require a coil of a magnitude much larger than about 0.6mH, so I was mainly stating that a 1.1mH coil is a rather large value to use in a tweeter circuit.
Being this, and the fact that you have a ~4 ohm resistor as your DCR value, the coil really is not doing all that much. If it were say 2.5 ohms or less, the additional coil might actually be contributing quite a bit more to the response than it truly is currently.
Thusly, my response to you was targeted that the coil and resistor might not really be a necessary component addition to the circuit to get the response profile you are trying to achieve, and not really worth the additional cost.
Hope that helps,
Wolf
Being this, and the fact that you have a ~4 ohm resistor as your DCR value, the coil really is not doing all that much. If it were say 2.5 ohms or less, the additional coil might actually be contributing quite a bit more to the response than it truly is currently.
Thusly, my response to you was targeted that the coil and resistor might not really be a necessary component addition to the circuit to get the response profile you are trying to achieve, and not really worth the additional cost.
Hope that helps,
Wolf
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You are basically right, that high mH coil is rarely needed in typical dome tweeter crossovers, but from my experience, it is little bit different for waveguided domes, and especially with low crossover point and high sensitivity. I added graphs when coil is disconnected. Without the coil, FR is more LR2.
So far these are just preparational steps, it looks that desired slope and Fc can be realized with very simple filter.
So far these are just preparational steps, it looks that desired slope and Fc can be realized with very simple filter.
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