Dear audio enthusiasts,
I am new on the forum, and generally new to audio related stuff. Since I'm doing something like this for the first time I'd like to ask for some help in designing and building a small waterproof enclosure for an outdoor speaker. This isn't your typical audiophile project, but more like a simple DIY hobby project of mine. I'm building a small audio device with a single speaker (mono) that will be installed somewhere outside, most likely up on a tree in an open field. The device will periodically play various animal sounds like bird songs and the like. It will be solar-powered, so I will probably want an efficient design to convert maximum amount of energy into sound. The electronics and the PCB are mostly finished - there's a solar battery charger, there's a microcontroller, there's audio data storage, and there's a class-D amplifier IC on the board. I just need to wire up and stuff everything into a box.
I'm having some trouble understanding how to build this box. It's supposed to be waterproof, so wood is likely out of the question. It'll probably be PVC plastic or maybe epoxy/fiberglass, but that's not the main issue. What I'd like to ask about is the shape/size of the box. I've already tried building a test box like a small closed enclosure, but the sound coming out was heavily distorted with some hissing. It sounded like the lower frequencies were more pronounced while the higher frequencies have been cut as if the box acted like a low-pass filter. Then I tried the same speaker with a simple dipole (a plywood board with a hole in the middle), and it worked wonders. There was nice clear sound with no hissing at all. Also, opening the former box did help plenty with the sound quality. Now obviously, I cannot use a flat dipole board directly since it's not waterproof, but I am guessing I will have to use something that is opened on both sides of the speaker to maximize loudness? I also don't want it too big as it's going to be a pain to mount on a tree. Bass and lower frequencies aren't really an issue for this project.
Any suggestions how I should go about?
The speaker I'm using is this one (12 Watt): https://www.cuidevices.com/product/resource/pdf/gf0876m.pdf
Thanks in advance!
I am new on the forum, and generally new to audio related stuff. Since I'm doing something like this for the first time I'd like to ask for some help in designing and building a small waterproof enclosure for an outdoor speaker. This isn't your typical audiophile project, but more like a simple DIY hobby project of mine. I'm building a small audio device with a single speaker (mono) that will be installed somewhere outside, most likely up on a tree in an open field. The device will periodically play various animal sounds like bird songs and the like. It will be solar-powered, so I will probably want an efficient design to convert maximum amount of energy into sound. The electronics and the PCB are mostly finished - there's a solar battery charger, there's a microcontroller, there's audio data storage, and there's a class-D amplifier IC on the board. I just need to wire up and stuff everything into a box.
I'm having some trouble understanding how to build this box. It's supposed to be waterproof, so wood is likely out of the question. It'll probably be PVC plastic or maybe epoxy/fiberglass, but that's not the main issue. What I'd like to ask about is the shape/size of the box. I've already tried building a test box like a small closed enclosure, but the sound coming out was heavily distorted with some hissing. It sounded like the lower frequencies were more pronounced while the higher frequencies have been cut as if the box acted like a low-pass filter. Then I tried the same speaker with a simple dipole (a plywood board with a hole in the middle), and it worked wonders. There was nice clear sound with no hissing at all. Also, opening the former box did help plenty with the sound quality. Now obviously, I cannot use a flat dipole board directly since it's not waterproof, but I am guessing I will have to use something that is opened on both sides of the speaker to maximize loudness? I also don't want it too big as it's going to be a pain to mount on a tree. Bass and lower frequencies aren't really an issue for this project.
Any suggestions how I should go about?
The speaker I'm using is this one (12 Watt): https://www.cuidevices.com/product/resource/pdf/gf0876m.pdf
Thanks in advance!
Design-wise, I see few points that might need to be taken care of:
1) It has to be able to get really loud to sound like a bird, especially in outdoor conditions. Some power would be needed.
2) The ambient temperature due to outdoor conditions and related power dissipation issues to be addressed. Solar power means it'd be running during sunlight hours.
3) Fully plastic would not be a good idea if the thermal relief needs to be efficient. A little aluminium maybe..
If I were you, I'd pick a megaphone (horn) as birds do not usually make low frequencies. Horns are efficient and loud and need less power especially when large distances are involved.
Animals make low frequencies using the resonance of their mouth / throat parts, but it is generally hard for a loudspeaker to make bass outdoors without getting large in size.
1) It has to be able to get really loud to sound like a bird, especially in outdoor conditions. Some power would be needed.
2) The ambient temperature due to outdoor conditions and related power dissipation issues to be addressed. Solar power means it'd be running during sunlight hours.
3) Fully plastic would not be a good idea if the thermal relief needs to be efficient. A little aluminium maybe..
If I were you, I'd pick a megaphone (horn) as birds do not usually make low frequencies. Horns are efficient and loud and need less power especially when large distances are involved.
Animals make low frequencies using the resonance of their mouth / throat parts, but it is generally hard for a loudspeaker to make bass outdoors without getting large in size.
" outdoor" speakers usually just use a more waterproof cone material
instead of paper etc etc.
You just dont want water to puddle up or fill the enclosure.
Enclosure is just plastic/ pvc/ metal etc etc.
Think of speaker at a fast food order window.
It is just outdoor speaker mounted in metal box
with normal grill in front.
Otherwise in tree driver could face down.
Just use a plastic bowl or plastic / metal case with speaker grill cover
driver used / shown is nothing high quality but does
appear to have plastic Mylar cone to be weather resistant.
If you want really loud or efficiency then use larger speaker
such as 6.5" or even 8" weatherproof
Bird sounds are higher in frequency so you can also
use Paging horn for very high efficiency.
Very loud with even low power
Or also called re entrant horn
Many / most also waterproof
Enclosure already made and mounting system also included
Doesnt need to be very large horn for high frequency
but if lower frequency wanted just use bigger horn.
instead of paper etc etc.
You just dont want water to puddle up or fill the enclosure.
Enclosure is just plastic/ pvc/ metal etc etc.
Think of speaker at a fast food order window.
It is just outdoor speaker mounted in metal box
with normal grill in front.
Otherwise in tree driver could face down.
Just use a plastic bowl or plastic / metal case with speaker grill cover
driver used / shown is nothing high quality but does
appear to have plastic Mylar cone to be weather resistant.
If you want really loud or efficiency then use larger speaker
such as 6.5" or even 8" weatherproof
Bird sounds are higher in frequency so you can also
use Paging horn for very high efficiency.
Very loud with even low power
Or also called re entrant horn
Many / most also waterproof
Enclosure already made and mounting system also included
Doesnt need to be very large horn for high frequency
but if lower frequency wanted just use bigger horn.
Foresters also hate screws and nails in trees because they ruin the blades in saw mills.
I have in the past used soda bottles with the top cut off with the bottom up and what was the top pinched closed and sealed with hot melt glue with any wires passing through the seal.
If you use one of those out door horn speakers make sure you get the right one as many are made to work on 70/100 volt systems by default.
I have in the past used soda bottles with the top cut off with the bottom up and what was the top pinched closed and sealed with hot melt glue with any wires passing through the seal.
If you use one of those out door horn speakers make sure you get the right one as many are made to work on 70/100 volt systems by default.
Horn speaker driver for re entrant/paging horn is usually 8 ohm
The 70 volt systems come with a line matching transformer
So if you just want 8 ohms
dont use the transformer.
So basically all of them are compatible impedance wise.
Of course the included drivers range in design and cost.
But some are basically a speaker much like yours.
It is just in a enclosure with horn loading for more efficiency
The 70 volt systems come with a line matching transformer
So if you just want 8 ohms
dont use the transformer.
So basically all of them are compatible impedance wise.
Of course the included drivers range in design and cost.
But some are basically a speaker much like yours.
It is just in a enclosure with horn loading for more efficiency
Member @hal4287 has experience with solar-powered electronics that have to work outdoors continuously, but in his case it was for monitoring migrating birds - it didn't make but analyse sound. https://www.diyaudio.com/community/threads/need-advice-for-a-weird-project.352655/post-6159052 Unfortunately he hasn't been on this forum since 2022.
Hey, I think this answers my question.
It's true that my speaker has a plastic front cone that gives it water resistance, but the back-side of the speaker has exposed copper. I would want the back-side to be open so that the sound can travel out of the enclosure in some way and boost the overall volume. But since the speaker is a double-sided sound source and the sound generated on the back is 180° out of phase, something is needed to make sure that the two sources don't cancel each other out. This McDonald's teller box idea looks exactly what I want. A box with a speaker mounted in front, and an opening down on the bottom. Gives water resistance since water can't flow upwards, and I'll put a mesh over the bottom opening to prevent insects from nesting inside.
I see some of you have recommended a megaphone instead. Those horns do look promising, but they seem much more costly than what I originally envisioned. I'll keep it in mind for my next build. My current speaker is like 6 bucks or so, and its membrane is plastic (waterproof), so no worries!
Thanks for all suggestions so far!
The only way to get bass efficiently from a small sealed enclosure is to have a large enclosure... You can have upto two of
1) compact size
2) efficient operation
3) deep bass
but not all three... A ported enclosure will help, but then its exposed to condensation, insects, birds might nest in the port even!
For birdsong a horn tweeter sounds like a good fit, highly efficient, no bass (but you don't need it for birdsong). For more general sounds a larger box like bookshelf speaker would be appropriate.
1) compact size
2) efficient operation
3) deep bass
but not all three... A ported enclosure will help, but then its exposed to condensation, insects, birds might nest in the port even!
For birdsong a horn tweeter sounds like a good fit, highly efficient, no bass (but you don't need it for birdsong). For more general sounds a larger box like bookshelf speaker would be appropriate.