Hello everyone,
I am planning to build an active 3-way loudspeaker. I would like to use four side-mounted woofers (10 inch), two midrange drivers (6.5 inch) and an Air Motion Transformer as a tweeter.
Everything sounds quite normal, but why two midrange drivers? I would like to have a wide horizontal dispersion, but a strongly focused vertical dispersion. To achieve this, I don't want to use the “classic” M-T-M arrangement, but bring the two midrange drivers closer together and place them directly above each other (about 18 cm distance between the centers of the drivers) and place the AMT directly above them. Due to its design, the AMT already has a strong vertical directivity with a wide horizontal sound dispersion.
I plan to use crossover frequencies of approx. 80-100 Hertz and a fairly low 1150 - 1200 Hz. My own calculations based on Excel templates from the forum have shown that a crossover frequency higher than 1200 Hz could cause problems with unwanted lobes in the midrange.
I have not yet completely decided on the drivers. I have the following favorites:
You can find a very simple concept sketch of the speaker from the front and from the side in the attachment. B = Bass, M = Midrange, AMT = AMT 🙂. I am thinking about dividing the loudspeaker in two cabinets per side to make it easier to handle. The thin lines in the back have a recurring distance of 10cm. Hence, the loudspeaker would be around 135cm high.
I would be very interested to hear what you think of this concept and what suggestions and ideas you have for improvement.
Thank you and best regards
Klaus
I am planning to build an active 3-way loudspeaker. I would like to use four side-mounted woofers (10 inch), two midrange drivers (6.5 inch) and an Air Motion Transformer as a tweeter.
Everything sounds quite normal, but why two midrange drivers? I would like to have a wide horizontal dispersion, but a strongly focused vertical dispersion. To achieve this, I don't want to use the “classic” M-T-M arrangement, but bring the two midrange drivers closer together and place them directly above each other (about 18 cm distance between the centers of the drivers) and place the AMT directly above them. Due to its design, the AMT already has a strong vertical directivity with a wide horizontal sound dispersion.
I plan to use crossover frequencies of approx. 80-100 Hertz and a fairly low 1150 - 1200 Hz. My own calculations based on Excel templates from the forum have shown that a crossover frequency higher than 1200 Hz could cause problems with unwanted lobes in the midrange.
I have not yet completely decided on the drivers. I have the following favorites:
- 10-inch bass: Purifi PTT10, SB acoustics WO24-TX, Scan Speak 26W
- 6.5 inch midrange: Purifi PTT6.5, SB acoustics MW16-TX, Accuton C173
- AMT: Mundorf 197PP27R-7
You can find a very simple concept sketch of the speaker from the front and from the side in the attachment. B = Bass, M = Midrange, AMT = AMT 🙂. I am thinking about dividing the loudspeaker in two cabinets per side to make it easier to handle. The thin lines in the back have a recurring distance of 10cm. Hence, the loudspeaker would be around 135cm high.
I would be very interested to hear what you think of this concept and what suggestions and ideas you have for improvement.
Thank you and best regards
Klaus
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Hi Klaus,
I am afraid I will be no big help for you, but please keep us posted on your progress, sounds very promising, especially when you will use the Purifi drivers.
Just one mention: I guess the Purifi PTT6.5 M you would need to cross higher than you intend, probably around 300HZ from what I have seen 🙂
Greetings,
Thommy
I am afraid I will be no big help for you, but please keep us posted on your progress, sounds very promising, especially when you will use the Purifi drivers.
Just one mention: I guess the Purifi PTT6.5 M you would need to cross higher than you intend, probably around 300HZ from what I have seen 🙂
Greetings,
Thommy
Hi there,
very interesting project with the adoption of the pro Mundorf AMT for very high max SPL
i also believe that the challenge will be to find the right crossover point to achieve a similar max SPL in the low mid range with 2 6.5 inch woofer
i also would like to ask which is the measurement equipment and the simulation program you want to use
in addition i want to mention that there is another approach to control directivity with a (need to be quite large though) wave guide also for one mid range instead of the use of two in woofer - tweeter - woofer placement
here a small example of what i have used for testing some times ago with a 8 inch Sonido mid range driver, here the front horn has no difference in vertical to horizontal directivity here the main goal is to reduce the cone excursion in the low mid range frequency range
so far - so good, Stefano
very interesting project with the adoption of the pro Mundorf AMT for very high max SPL
i also believe that the challenge will be to find the right crossover point to achieve a similar max SPL in the low mid range with 2 6.5 inch woofer
i also would like to ask which is the measurement equipment and the simulation program you want to use
in addition i want to mention that there is another approach to control directivity with a (need to be quite large though) wave guide also for one mid range instead of the use of two in woofer - tweeter - woofer placement
here a small example of what i have used for testing some times ago with a 8 inch Sonido mid range driver, here the front horn has no difference in vertical to horizontal directivity here the main goal is to reduce the cone excursion in the low mid range frequency range
so far - so good, Stefano
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