Is a parallel connection to the amp part of this conversation or not?
Edit: Happy Birthday Dave!
Edit: Happy Birthday Dave!
Last edited:
Hi revboden
You have the idea.
Keep in mind for two radiators to be a quarter wavelength or less apart, the center to center distance is automatically less because of the radiator’s diameter.
While the on axis SPL is the same for the far and close cases (the distance from the source to the microphone is the same in each case), the difference in the radiated power is the absence of the nulls where the two sources cancel each other (the phase difference is 1,3,5 etc X 180 degrees at the nulls).
If one models two identical sources, ½ wavelength apart, you find they produce a polar null in line with the array and radiate a figure 8 radial doughnut shape or broadside. The greater the acoustic spacing, the larger the number of lobes and nulls.
That interference pattern is why large arrays used in live sound have such a high sound level behind / under and to the sides of the array, the sound doesn’t always go where the cone is pointed haha.
The total acoustic power is what one gets if you add the assay the energy over the surface of a sphere surrounding the systems.
The traditional way was to do this test in a highly reverberant room (opposite of an anechoic chamber) because the reverberant level is the sum of all the radiation power and rate of absorption. This is rarely done at low frequencies because the room must be many wavelengths on the smallest dimension.
The Riverbanks acoustics labs has such a room and by documenting the room’s size limited aspects, they can to a degree correct a measurement for somewhat lower frequencies.
In room acoustics at higher frequencies, where the room can be huge compared to the wl, that reverberant energy is the biggest enemy.
It is why a handclap has a long decay and why it is so hard to get good sound from speakers,
SO much of what arrives at the ears is reflected sound, not the part that contains the information. Here either being closer or having more directivity is the only way to reach where one can understand words or for that matter in the home, preserve the recorded stereo image, each case requiring a larger direct than reflected sound level.
Best,
Tom
You have the idea.
Keep in mind for two radiators to be a quarter wavelength or less apart, the center to center distance is automatically less because of the radiator’s diameter.
While the on axis SPL is the same for the far and close cases (the distance from the source to the microphone is the same in each case), the difference in the radiated power is the absence of the nulls where the two sources cancel each other (the phase difference is 1,3,5 etc X 180 degrees at the nulls).
If one models two identical sources, ½ wavelength apart, you find they produce a polar null in line with the array and radiate a figure 8 radial doughnut shape or broadside. The greater the acoustic spacing, the larger the number of lobes and nulls.
That interference pattern is why large arrays used in live sound have such a high sound level behind / under and to the sides of the array, the sound doesn’t always go where the cone is pointed haha.
The total acoustic power is what one gets if you add the assay the energy over the surface of a sphere surrounding the systems.
The traditional way was to do this test in a highly reverberant room (opposite of an anechoic chamber) because the reverberant level is the sum of all the radiation power and rate of absorption. This is rarely done at low frequencies because the room must be many wavelengths on the smallest dimension.
The Riverbanks acoustics labs has such a room and by documenting the room’s size limited aspects, they can to a degree correct a measurement for somewhat lower frequencies.
In room acoustics at higher frequencies, where the room can be huge compared to the wl, that reverberant energy is the biggest enemy.
It is why a handclap has a long decay and why it is so hard to get good sound from speakers,
SO much of what arrives at the ears is reflected sound, not the part that contains the information. Here either being closer or having more directivity is the only way to reach where one can understand words or for that matter in the home, preserve the recorded stereo image, each case requiring a larger direct than reflected sound level.
Best,
Tom
Hi , I'm Aaron a total green horn(NEWBER) 😂 Unfortunately got rid of $1000 APPERENTLY. E
mbarrassed to say this, but I purchased a yr back,
(4)-Morel CAW938 9" with advice of wiring in parallel /86dB's up to 92dB's
In the same purchase I got:
(2) Morel CAT308-Tweeters 91dB's /each
(2)DAYTON PASSIVE 2500KHZ X-Overs I need help because I asked for a 2-way design that could later be modified into a KICK-BUTT 12"/15" CLASSIC 3-WAT DESIGN. HELPPP. THANKS GUYS👍
mbarrassed to say this, but I purchased a yr back,
(4)-Morel CAW938 9" with advice of wiring in parallel /86dB's up to 92dB's
In the same purchase I got:
(2) Morel CAT308-Tweeters 91dB's /each
(2)DAYTON PASSIVE 2500KHZ X-Overs I need help because I asked for a 2-way design that could later be modified into a KICK-BUTT 12"/15" CLASSIC 3-WAT DESIGN. HELPPP. THANKS GUYS👍
Semi-random parts with their leads cut short and inconvieninly soldered to a board? Not much use as a crossover. A crossover is the hardest part of a multi-way and an off-the—shelf XO is not much use but for parts.
2 woofers gives +3dB of level. If you wir them in parallel you get another 3dB from the lower impedance and if you connect in series you lose 3dB, so to get eirther +6dB or none.
dave
Last edited:
How or what is my best option if I told you I don't actually have a computer now and doubt seeing myself building real passive /CUSTOME X-OVERS?
I actually thought 🤔 MAYBE if I asked the right guy , he might be willing to nudge this along for me somehow if I needed a pair of these ❌ designed based on the specs alone for a more accurate sound and quality. Be so cool after having the speakers for over a year and putting some demo cabs up for them ,I had hoped for some better progress on getting them finished but I'm slow trying to get used to the forum and finding my way around it,plus just time consumed searching online for a schematics/parts list for 2-way using these 9"ers +1"cat308🤷
😁
Hey thanks for info,
I actually thought 🤔 MAYBE if I asked the right guy , he might be willing to nudge this along for me somehow if I needed a pair of these ❌ designed based on the specs alone for a more accurate sound and quality. Be so cool after having the speakers for over a year and putting some demo cabs up for them ,I had hoped for some better progress on getting them finished but I'm slow trying to get used to the forum and finding my way around it,plus just time consumed searching online for a schematics/parts list for 2-way using these 9"ers +1"cat308🤷
😁
Hey thanks for info,
Cross-overs? Not me.
See if this thread helps? https://www.diyaudio.com/community/...igning-crossovers-without-measurement.189847/
dave
See if this thread helps? https://www.diyaudio.com/community/...igning-crossovers-without-measurement.189847/
dave
Data sheets for the Morels here:
https://www.morelhifi.com/wp-content/uploads/2020/01/CAW938.pdf
https://www.morelhifi.com/wp-content/uploads/2020/01/CAT308.pdf
long story short, those drivers won't work well together as a 2 way
I'd say sell them & buy a kit
https://www.morelhifi.com/wp-content/uploads/2020/01/CAW938.pdf
https://www.morelhifi.com/wp-content/uploads/2020/01/CAT308.pdf
long story short, those drivers won't work well together as a 2 way
I'd say sell them & buy a kit
