I want to build a small violin amp, with two FaitalPro 3FE32 drivers, each in a separated sealed enclosure compartments.
I've used the calculator on this site to calculate the optimal enclosure volume:
https://www.diyaudioandvideo.com/Calculator/SpeakerBoxEnclosure/
It gives me a the following:
Vb = 0.46 liters (0.02 ft3) (Speaker Box Internal Volume)
f3 = 216.06 Hz (3dB Cutoff Frequency)
fb = 216.03 Hz (Enclosure Resonant Frequency)
The parameters I entered were (Vas = 1.3 lts, fs = 110 Hz, Qts = 0.36, Qtc = 0.707)
(Not sure if I chose the right Qtc)
On the parts-express site, it suggests a volume of 0.01 ft3 (0.28 liter, wich would give a sealed F3 of 244Hz) :
https://www.parts-express.com/FaitalPRO-3FE22-3-Neodymium-Professional-Woofer-4-Ohm-294-1100
I then used this other calculator: http://www.mh-audio.nl/Calculators/CBCV.html
Which shows me a response curve given the thiele-smap params, and the desired volume.
I'm not too surprized that the calculators don't all agree, but they are kind of far appart (0.46 vs 0.28 liter), and the volume seems pretty small, and I'm not so confident I'm using the calculator correctly.
I've used the calculator on this site to calculate the optimal enclosure volume:
https://www.diyaudioandvideo.com/Calculator/SpeakerBoxEnclosure/
It gives me a the following:
Vb = 0.46 liters (0.02 ft3) (Speaker Box Internal Volume)
f3 = 216.06 Hz (3dB Cutoff Frequency)
fb = 216.03 Hz (Enclosure Resonant Frequency)
The parameters I entered were (Vas = 1.3 lts, fs = 110 Hz, Qts = 0.36, Qtc = 0.707)
(Not sure if I chose the right Qtc)
On the parts-express site, it suggests a volume of 0.01 ft3 (0.28 liter, wich would give a sealed F3 of 244Hz) :
https://www.parts-express.com/FaitalPRO-3FE22-3-Neodymium-Professional-Woofer-4-Ohm-294-1100
I then used this other calculator: http://www.mh-audio.nl/Calculators/CBCV.html
Which shows me a response curve given the thiele-smap params, and the desired volume.
I'm not too surprized that the calculators don't all agree, but they are kind of far appart (0.46 vs 0.28 liter), and the volume seems pretty small, and I'm not so confident I'm using the calculator correctly.
The calculators mostly agree, it's more about how the end data is interpreted.
Seems like you'd probably be happy putting the two 3FE32 on each end in a 1 liter tube to get the best coverage, make another tube if it's not loud enough.
Edit:
Thought about something a bit eccentric, maybe you could make a light helmet of sorts with 4 drivers pointing in different directions, the sound would carry over the heads of those around you and it would also make a lot of direct sound come from you. Most people might think it's an original idea (makes you stand out a bit) and you don't have to carry stuff with straps and whatnot.
Last edited:
I've thought about a helmet configuration, I might try it, another helmet configuration would be an omni directional enclosure, by pointing a driver upwards against a wood, or 3d printed ABS cone. I would probably need a louder speaker for this, since it would be alone.
It depends. The Qt is more like .43 btw. This driver's fr slopes upwards. If the enclosure is too small, it will sound thin. You want to have some high Q bump on the low end so a smallish enclosure will sound more balanced.
How would you suggest obtaining this low end bump ? Bass reflex ?
There will be a preamp with EQ in front of the amp : https://www.fishman.com/portfolio/platinum-stage-eq-di-analog-preamp-pro-plt-301/
So I suppose that could be used to get a bump in the low end ?
For this amp, the low end will start at 196 hz, the G string of the violin.
If you can EQ its not critical with the volume. Make it as big you can fit on your head 🙂 but I would think > 0,5L and you must start here to consider the actual volume of the driver itself as it will take a big portion of any box or tube...
I would watch my ears... at higher frequencies it will be a quite narrow dispersion and if you ware it on top of your head it will be no problem but at lower-ish frequencies there could be in the long run. Wear ear protection of some sort? To compete with big horns for attention to an audience 50-100 feet away will require some steam...i
Why not a tube with one driver on both ends. No audience in the direction of a marching band or one would be stampede over 🙂 so to cover the sides should be ok!?
For stage this is not ideal so maybe 2 tubes which could be set to either 180 deg or 90 deg fwd on top of a helmet? 🙂
Happy marching.
I would watch my ears... at higher frequencies it will be a quite narrow dispersion and if you ware it on top of your head it will be no problem but at lower-ish frequencies there could be in the long run. Wear ear protection of some sort? To compete with big horns for attention to an audience 50-100 feet away will require some steam...i
Why not a tube with one driver on both ends. No audience in the direction of a marching band or one would be stampede over 🙂 so to cover the sides should be ok!?
For stage this is not ideal so maybe 2 tubes which could be set to either 180 deg or 90 deg fwd on top of a helmet? 🙂
Happy marching.
So, maybe a backpack instead of a helmet?... 2 high efficiency mids on opposite sides of a thin plywood box?
Don't forget to add the volume of the drive unit to any calculations. Faital Pro helpfully give this as 0.06 litres. And if you go for reflex, add the port volume too.
Make the enclosure small. You will have less bass extension but the speaker will sound fuller nonetheless. This is true for closed boxes.
One thing to keep in mind is for every 3dB of lost efficiency, amplifier wattage and battery power will need to double.
When i first looked at the thread i thot 3FE22 (whih i have), seems 3FE32 is a typo?
dave