I'm planning on building a pocket-sized portable computer speaker consisting of parts available from EBay under the goals of being loud as well as being as simple and cost-effective as possible, with hopes that I can build more if I choose to.
I plan to build off of a pre-built enclosure to mount both the drivers and the amp into that has around ~40-50mm of thickness so it'll fit in a pocket while fitting a 30mm high speaker with a couple mm of extra headroom, and ~120mm of length so both drivers can fit right beside each other at the top, and for that I found a 128x67x45mm plastic project box: 1X Wisher Plastic BOX WCA H2853 Electronics Enclosure Project Case 128 X67X 45mm | eBay
For the amplifier, I plan to use a PAM8610, and I'll match them with this pair of ~$11CAD full-range speakers I found on EBay: 2pcs 2 5" Inch 8ohm 8? 15W Full Range Audio Speaker Loudspeaker FOR Samsung HT | eBay
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Being a sealed enclosure, it was my initial plan to stuff the enclosure with pillow stuffing or line the inside with sound-deadening foam padding to acoustically isolate the inside, because I've been finding a bunch of opinions hinting it'd be improving bass extension and tone due to reducing phase cancellation with waves coming from the back of the cone.
Now, upon further research, I'm seeing things like it's it's not a good idea to stuff the box with isolation, because I'd be making some energy go to waste and reduce SPL, and I'm seeing people say it's a better idea to focus on rounding the internal enclosure somehow (sealant foam spray perhaps?) to reduce standing waves.
Interestingly, I see ~70 little bumps around the inside as well as four screw posts around the inside of the box (according to the third and fourth photo), which to me kind of looks like enclosure bracing; Would this work to my advantage or is this trivial?
What is the proper way to optimize the acoustics inside of my speaker box for the best sound quality and loudness efficiency with what I got?
I plan to build off of a pre-built enclosure to mount both the drivers and the amp into that has around ~40-50mm of thickness so it'll fit in a pocket while fitting a 30mm high speaker with a couple mm of extra headroom, and ~120mm of length so both drivers can fit right beside each other at the top, and for that I found a 128x67x45mm plastic project box: 1X Wisher Plastic BOX WCA H2853 Electronics Enclosure Project Case 128 X67X 45mm | eBay
For the amplifier, I plan to use a PAM8610, and I'll match them with this pair of ~$11CAD full-range speakers I found on EBay: 2pcs 2 5" Inch 8ohm 8? 15W Full Range Audio Speaker Loudspeaker FOR Samsung HT | eBay
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Being a sealed enclosure, it was my initial plan to stuff the enclosure with pillow stuffing or line the inside with sound-deadening foam padding to acoustically isolate the inside, because I've been finding a bunch of opinions hinting it'd be improving bass extension and tone due to reducing phase cancellation with waves coming from the back of the cone.
Now, upon further research, I'm seeing things like it's it's not a good idea to stuff the box with isolation, because I'd be making some energy go to waste and reduce SPL, and I'm seeing people say it's a better idea to focus on rounding the internal enclosure somehow (sealant foam spray perhaps?) to reduce standing waves.
Interestingly, I see ~70 little bumps around the inside as well as four screw posts around the inside of the box (according to the third and fourth photo), which to me kind of looks like enclosure bracing; Would this work to my advantage or is this trivial?
What is the proper way to optimize the acoustics inside of my speaker box for the best sound quality and loudness efficiency with what I got?
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Hi,
You haven't a hope in hell of building a fully featured miniature
boombox for anything like the price of a commercial product.
You can't DIY small high value stuff, its too expensive.
rgds, sreten.
You haven't a hope in hell of building a fully featured miniature
boombox for anything like the price of a commercial product.
You can't DIY small high value stuff, its too expensive.
rgds, sreten.
In no way am I aiming to make it a fully-featured boombox, but rather just a simple self-powered speaker pair connected to a PAM8610 with a simple 3.5mm input. I've listed the parts I plan to get and it all fits within my set budget, all I want is to know how to modify the inside of the box for the most ideal acoustics I can achieve in terms of volume and sound quality
Don't mind Sreten - I would have said the same thing too but if you are doing this for DIY fun and learning - great.
Those Samsung drivers actually look really interesting. I would be curious to measure them as a driver for FAST in the Subjective Blind threads.
So here are tips.
Use polyfill stuffing - it will increase virtual box volume. Use felt behind and adjacent to drivers inside box.
Use a baffle step circuit or EQ to get flat response or it will sound too forward.
Use a better amp if you want. - TPA3110D2 to get 8 watts of clean power.
Good luck.
Those Samsung drivers actually look really interesting. I would be curious to measure them as a driver for FAST in the Subjective Blind threads.
So here are tips.
Use polyfill stuffing - it will increase virtual box volume. Use felt behind and adjacent to drivers inside box.
Use a baffle step circuit or EQ to get flat response or it will sound too forward.
Use a better amp if you want. - TPA3110D2 to get 8 watts of clean power.
Good luck.
I was thinking about stuffing the enclosure initially, then I was unsure after I saw the opinions saying "this will displace air in the enclosure, meaning the total volume of air in your enclosure will be reduced" and "you are making a compromise about where some of that energy is going." What are your thoughts about this?
Also, is the "acousta-stuff" polyfill solution worth the extra $30 in shipping costs to Canada over the 'polyester fill' stuff that I can buy at my local Walmart? Alternatively, what do you think about lining up the enclosure with SilverStone SF01 Silent Foam instead?
The baffle step circuit, out of what I'm reading on it, it sounds very tempting, but I haven't found any good resources to help me build such a thing, but I'd imagine it would be too advanced for me anyway. I don't mind using a software EQ from the input source if it turns out to be needed.
Now, the mention of trying a different amplifier such as the TPA3110D2 is interesting to me, mainly because I've only familiarized myself with the LM386, PAM 8403, 8406, and 8610 chips.
When comparing directly with the PAM8610 amplifier, do you still imagine an increase of power over that TPA chip? According to the 8610's Datasheet, 10W of power was measured with a 8Ohm load with a 1Khz tone.
Part of what inspired me to build this is the Aker MR700 12W self-powered speaker. Despite its pocket-size and average sound quality, it could produce insanely loud clean volume; Using a 3Khz sine wave I've measured a SPL of 118db at 20CM away. I'm interested and curious to hear how close I could get to that volume in combination of better sound, and whether I even exceed the MR2700s volume.
The stuffing takes very little volume and actually has the real effect of increasing the volume seen by the driver. That's why it is used. Save your money and take an old pillow apart for stuffing. Fiberglass works too.
118dB at 20cm is not hard - -6dB for every 2x distance son-12dB at 80cm or circa -14dB at 1m or 104dB at 1 m. Still loud though if plays clean.
I don't know about the other amps but TPA's are essentially state of the art and sound very good. I like TDA7492 as well. You can get those for $6 and they can out out probably 25w easily clean.
A lot of this depends on the driver. You are far better off getting drivers with published TS parameters so you can predict the performance before buying.
The Vifa TC7FD is also very nice and Peerless P830983 is compact and very good too. also look at Tang Band W2-852SH.
118dB at 20cm is not hard - -6dB for every 2x distance son-12dB at 80cm or circa -14dB at 1m or 104dB at 1 m. Still loud though if plays clean.
I don't know about the other amps but TPA's are essentially state of the art and sound very good. I like TDA7492 as well. You can get those for $6 and they can out out probably 25w easily clean.
A lot of this depends on the driver. You are far better off getting drivers with published TS parameters so you can predict the performance before buying.
The Vifa TC7FD is also very nice and Peerless P830983 is compact and very good too. also look at Tang Band W2-852SH.
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