good morning everyone.
I've been working on the realization (on paper) of my final speaker for a few months. After doing a lot of research I was able to choose the components, the size of the cabinet, and some drafts of how it should be once completed.
so it will be an active system with dsp minidsp flex htx, hypex and purifi power amps.
I have an 18 subwoofer that covers frequencies from 20 hz to 65 hz.
So I chose the tweeter with double dipole horn beyma tpl 200.
midrange: it will be in a closed box independent from the cabinet for the woofer, the volume will be about 5 liters, and the transducer will be the 18 suoni 6nmb900. woofer: 12 eminence Deltalite 2512 II
or FaitalPRO 12PR 300 4 ohm.
The volume of the box with the Faital transducer would be 55 liters with Q 0.685.
The box with the Eminence transducer would be 65 liters with Q of 0.707.
The uncertainty of the woofer comes from the fact that I don't know how well the Faital can hold the high frequencies without distorting and how qualitatively valid it is up to frequencies of 500/700hz. Or I could keep it up to frequencies of 250/300hz, but then beyond these frequencies I don't know if the midrange would return a big and full-bodied sound as I want. For the cuts I had thought 65/700 48db, 700/2500 48db, 2500/20000. Do you have any advice on this?
regarding the buffle I had thought of a narrow and tapered cabinet, with very rounded edges for the woofer and midrange. I am not sure if the woofer should be far from the midrange and tweeter, or as close as possible. All advice and opinions are welcome.
I've been working on the realization (on paper) of my final speaker for a few months. After doing a lot of research I was able to choose the components, the size of the cabinet, and some drafts of how it should be once completed.
so it will be an active system with dsp minidsp flex htx, hypex and purifi power amps.
I have an 18 subwoofer that covers frequencies from 20 hz to 65 hz.
So I chose the tweeter with double dipole horn beyma tpl 200.
midrange: it will be in a closed box independent from the cabinet for the woofer, the volume will be about 5 liters, and the transducer will be the 18 suoni 6nmb900. woofer: 12 eminence Deltalite 2512 II
or FaitalPRO 12PR 300 4 ohm.
The volume of the box with the Faital transducer would be 55 liters with Q 0.685.
The box with the Eminence transducer would be 65 liters with Q of 0.707.
The uncertainty of the woofer comes from the fact that I don't know how well the Faital can hold the high frequencies without distorting and how qualitatively valid it is up to frequencies of 500/700hz. Or I could keep it up to frequencies of 250/300hz, but then beyond these frequencies I don't know if the midrange would return a big and full-bodied sound as I want. For the cuts I had thought 65/700 48db, 700/2500 48db, 2500/20000. Do you have any advice on this?
regarding the buffle I had thought of a narrow and tapered cabinet, with very rounded edges for the woofer and midrange. I am not sure if the woofer should be far from the midrange and tweeter, or as close as possible. All advice and opinions are welcome.
So why do you prefer to cut at about 250/400hz and leave the midwoofer to do the rest up to about 2500/4000hz? 🤔
If you are asking about any benefit to crossing the 12" above 400Hz, yes, 400Hz to 700Hz is a power dense region of the spectrum. You might let the larger driver handle it.
Well, the way I learned it from the pioneers, the audio BW was broken up into an 11 octave spread: sub bass 16-60 Hz, bass -250 Hz, mids -2 kHz, high mids -6 kHz, HF -3.28 kHz.
Fh = Fl*2^n
Fl = Fh/2^n
n = ln(Fh/Fl)/ln(2)
where:
Fh = upper frequency
Fl = lower frequency
n = octave spread
ln(2) = 0.6931
From this they designed the 755 driver circa 1936, technically an 8" tri-ax with a nominally 80-12.5 kHz once seen in pretty much every building needing any PA speakers at least through the '60s.
Note too that for large PA apps they used 300 Hz between the woofer, tweeter horns Vs 500 - 800 Hz for cinema, music, etc. apps, so typically my upper limit.
Fh = Fl*2^n
Fl = Fh/2^n
n = ln(Fh/Fl)/ln(2)
where:
Fh = upper frequency
Fl = lower frequency
n = octave spread
ln(2) = 0.6931
From this they designed the 755 driver circa 1936, technically an 8" tri-ax with a nominally 80-12.5 kHz once seen in pretty much every building needing any PA speakers at least through the '60s.
Note too that for large PA apps they used 300 Hz between the woofer, tweeter horns Vs 500 - 800 Hz for cinema, music, etc. apps, so typically my upper limit.
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Since we’re talking DIY and the ability to develop a system for YOUR space….let’s take advantage of that.
First things first, calculate the Schroeder frequency of your room. Choose your XO frequency to your woofer within half an octave either way……now chose a woofer that works best within the passband that remains. Choose a midrange accordingly as well. Now you’re on the path to the best possible outcome for your space.
Now the midrange is working within the reverberant field of the space……directivity and room treatment need to be considered. You don’t have to be aggressive here….but some passive room acoustic treatment can go a long way.
First things first, calculate the Schroeder frequency of your room. Choose your XO frequency to your woofer within half an octave either way……now chose a woofer that works best within the passband that remains. Choose a midrange accordingly as well. Now you’re on the path to the best possible outcome for your space.
Now the midrange is working within the reverberant field of the space……directivity and room treatment need to be considered. You don’t have to be aggressive here….but some passive room acoustic treatment can go a long way.
