Vents of any kind around the diaphragm are most likely for cooling in order to improve power handling and reduce distortion.
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I tried damping the Enclosure with open cell foam and got rid of most of the wiggles and reduced the dip at 2700 Hz but I couldn't got rid of it entirely. Maybe i have to try different damping materials or the suggested open back enclosure by oleg. I guess one would lose some low end extention with an open back though?
I also tried the foam plug in the throat extention and that reduced some of the sharp high frequency swings by the cost of sensitivity. I lost around 2dB in the midrange and up to 10dB in the upper treble. But the distortion at 90 dB SPL is still down at -50 dB so it should be easily EQable for home listening levels.
That's probably not a good trade-off, 10 dB is a lot (too dense foam). But I was interested in your findings. When I tried this with an extended throat, it behaved differently - gave almost a flat level reduction across the band: https://www.diyaudio.com/community/...-design-the-easy-way-ath4.338806/post-7475065
In fact, it reduced the level of the extending resonance the most, which is perhaps expectable after all.
OK, i just plugged the whole extention with a 10 cm long cylinder yesterday. I just now tried a few different lengths.
red: without plug; green: 3cm plug; blue 5 cm; orange 10 cm
differences between no plug and 3, 5 and 10 cm.
With these results i think I'll stick to the smallest size of 3 cm. here I have the lowest loss in the midrange but still a bit tidier upper trebble than without a plug.
Thanks for the input.
red: without plug; green: 3cm plug; blue 5 cm; orange 10 cm
differences between no plug and 3, 5 and 10 cm.
With these results i think I'll stick to the smallest size of 3 cm. here I have the lowest loss in the midrange but still a bit tidier upper trebble than without a plug.
Thanks for the input.
Right now I have the horns placed right on top of my woofer enclosure, so the c-t-c distance is about 380mm which would mean its 0.44*λ (right in the region which kimmosto suggests not to use) I'd either have to raise the crossover to ~1000Hz (which is not feasable with my subwoofer driver) or raise the horn to a heigth of 1000mm above the Woofer and leave the crossover at 400 Hz which would look a bit silly in my opinion but would probably be worth a try I guess. I never before tried the 1.2*λ crossover before and am curious to how it sounds, especially when standing up, as there will be a large dip in the response just 5-10° above and below the design axis.
Guidance for standard tweeters and midrange drivers, not for 400Hz crossovers and large horns. Simulate it in Vituix and see what happens to the DI when you move the vertical distance, prepare to be underwhelmed
Do you have a measurement without the back enclosure attached? it seems as if acoustically it is not doing any good.
Your enclosure is certainly better behaved and I wouldn't expect this difference. Such narrow, relatively high-Q dips, like the one around 2.5 kHz, are typically not audible at all. With a custom casing I would expect that it should be possible to get rid of all the additional resonances, simply by enough damping (?).
- I should try something with the CD131 (and maybe with the HF1440 as well but that's a tough one).
- I should try something with the CD131
(and maybe with the HF1440 as well but that's a tough one).
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DE360, A520G2 with a) 25-STD-1 and b) a simple conical 1->1.4" extension + 36-STD-1 (absolute levels do not match):
a)
b)
I think I really need to collect all the available data and look properly into this to gather what's going on. There must be a simple and predictable principle, since at these wavelengths (below 2 kHz) it must all be at lumped-element level. This seems as a nice study case. The cut&try approach is not very sustainable...
a)
b)
I think I really need to collect all the available data and look properly into this to gather what's going on. There must be a simple and predictable principle, since at these wavelengths (below 2 kHz) it must all be at lumped-element level. This seems as a nice study case. The cut&try approach is not very sustainable...
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Mabat does your friends from Czechia tried STX again? https://stx.pl/category/glosniki-glosniki-estrada?horizontal
The Fane CD131
800Hz / 8 and 6 BQ
https://www.fane-international.com/downloads/Fane-CD131-DS240316.pdf
Is the impedance in the spec sheet correct?
Looks OK! The sensitivity looks lower than the other drivers.
DE360
800Hz / 6BQ
800Hz / 8 and 6 BQ
https://www.fane-international.com/downloads/Fane-CD131-DS240316.pdf
Is the impedance in the spec sheet correct?
Looks OK! The sensitivity looks lower than the other drivers.
DE360
800Hz / 6BQ