OK folks, I made a 50x90cm baffle for initial measurements. In this stage I'm mostly interested in what happens between 500 and 5000Hz, so open baffle on the bed and handheld mic are close enough. With dsp I must finetune response eq anyway when the divers are mounted in the final box. I will not use any simulation software.
Here is my lab, which happens to serve also as a guestroom now during holidays... but acoustically it's only for good! The baffle and speaker were positioned this way for measurements, mic distance was roughly 60cm. DAC is ODAC, amp is Vincent SV-129 and mic Minidsp UMIK-1, software REW.
I tested the effect of a serial capacitor too, an Audyn Cap Plus 4,7uF hit my fingers first. We can see that the responses are not hifi at all. There is "too much" undulation of spl in every angle, but avererage of 0-15deg is pretty good and easy to eq flat. These speakers will not be nearfield monitors, so I don't expect hearable problems.
Most challenge will come with the woofer's 5dB recession 1-1,7kHz, but fortunately dispersion is pretty smooth up to 3kHz and matches the horn well. I don't think that DI will be too high either.
Here is my lab, which happens to serve also as a guestroom now during holidays... but acoustically it's only for good! The baffle and speaker were positioned this way for measurements, mic distance was roughly 60cm. DAC is ODAC, amp is Vincent SV-129 and mic Minidsp UMIK-1, software REW.
I tested the effect of a serial capacitor too, an Audyn Cap Plus 4,7uF hit my fingers first. We can see that the responses are not hifi at all. There is "too much" undulation of spl in every angle, but avererage of 0-15deg is pretty good and easy to eq flat. These speakers will not be nearfield monitors, so I don't expect hearable problems.
Most challenge will come with the woofer's 5dB recession 1-1,7kHz, but fortunately dispersion is pretty smooth up to 3kHz and matches the horn well. I don't think that DI will be too high either.
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I discussed about the box layout with my son Timo, and we ended up making a wide curved front boxes like SF Stradivari. Then we must think about how to make them... One option is to copy the method of Troels and kimmosto, mdf http://www.troelsgravesen.dk/PMS.htm
My next mission however is to try out different diffusors for the horn, like Martion Bullfrog has https://www.alexgiese.de/das-kultivierte-biest-martion-bullfrog
Another way to go is aircell foam insert ala GedLee speakers http://www.gedlee.com/Loudspeakers/Loudspeakers.aspx
My next mission however is to try out different diffusors for the horn, like Martion Bullfrog has https://www.alexgiese.de/das-kultivierte-biest-martion-bullfrog
Another way to go is aircell foam insert ala GedLee speakers http://www.gedlee.com/Loudspeakers/Loudspeakers.aspx
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I made a lot of cuts to make my curved baffles smooth. Took some sanding and filler though to make the surface smooth. Will you make them deep with a curved baffle, or less depth and a curved back as well?
In any case, I would recommend to make the curved baffle as a separate part with a flat mating surface, and just glue it in when it's finished. The way I did it, I did not have access to the inside after the second panel was bent. I should have split it in two, and glued the two halves together when they were complete. As you can see in the picture, I also made the panels too narrow, so I had to add additional trim pieces to the sides later. A lot of mistakes in the way I built them created a lot of extra work. It would have been fairly straight forward if I did the front and rear as separate halves, and also had wider panels.
Below is a picture of some parts laid out before assembly.
In any case, I would recommend to make the curved baffle as a separate part with a flat mating surface, and just glue it in when it's finished. The way I did it, I did not have access to the inside after the second panel was bent. I should have split it in two, and glued the two halves together when they were complete. As you can see in the picture, I also made the panels too narrow, so I had to add additional trim pieces to the sides later. A lot of mistakes in the way I built them created a lot of extra work. It would have been fairly straight forward if I did the front and rear as separate halves, and also had wider panels.
Below is a picture of some parts laid out before assembly.
Qts - to have less spl variations. Phase plugs and diffusors have been used with coaxials and CD horns for ages!
Rallyfinnen - I haven't thought about this much yet. Perhaps I'll make backside half of hexagon and to have more depth. Perhaps the other 12" bass driver will be on the backside with the FA123
Rallyfinnen - I haven't thought about this much yet. Perhaps I'll make backside half of hexagon and to have more depth. Perhaps the other 12" bass driver will be on the backside with the FA123
I set up two xo schemes and EQ+delay on a Minidsp 2x4HD - here open test baffle measurements in the lab.
The woofer has bad diffraction just above 1kHz and horn just below 1kHz. Diffraction's cancellation dip cannot be EQ'd and in both versions it makes problems. As well horn's response is not smooth, but acceptable. Delay setting in both is 0,4ms for the woofer, and horn spl was attenuated for 8dB.
So, looks like I must follow closely to profiguy's tests! https://www.diyaudio.com/community/...ax-at-a-good-price.392861/page-2#post-7219024
LR2 at 1800Hx versus LR4 at 1200Hz
The woofer has bad diffraction just above 1kHz and horn just below 1kHz. Diffraction's cancellation dip cannot be EQ'd and in both versions it makes problems. As well horn's response is not smooth, but acceptable. Delay setting in both is 0,4ms for the woofer, and horn spl was attenuated for 8dB.
So, looks like I must follow closely to profiguy's tests! https://www.diyaudio.com/community/...ax-at-a-good-price.392861/page-2#post-7219024
LR2 at 1800Hx versus LR4 at 1200Hz
I believe alot of your problem lies with baffle step and diffraction. I also see issues in the crossover region likely caused by the measurement setup. The big gap from the horn edge to cone surround doesn't help with the area your struggling with, but before you measure on a proper baffle that won't cause cancelations, I wouldn't get too discouraged yet.
My test baffle is 20" / 50 cm. Most big coaxials come with even narrower boxes like Fyne 9" https://audio.com.pl/testy/stereo/kolumny-glosnikowe/3576-fyne-audio-f502#laboratory or Jones's MoFi 10s.
Coaxials are very difficult to make really smooth on-axis because of "too much" symmetry. 10deg off-axis response should be the reference.
Coaxials are very difficult to make really smooth on-axis because of "too much" symmetry. 10deg off-axis response should be the reference.
