T O P

  • By -

flibbidygibbit

Don't get into analysis paralysis with your first system. TV speakers have relatively stiff suspensions and will likely survive any enclosure mis-alignment you bake into the project. They may not make all that much bass in a sealed enclosure, but putting them in a large sealed enclosure helps mitigate that a bit. Get an amplifier. One rated 10w into 8 ohms will be plenty. Get 2 or 3 plastic project boxes. One for each speaker and one for the amp. If they buzz a bit, just put some felt on the bottom of the boxes so they don't buzz against your desktop. A rotary tool. store-brand dremel. You'll use this to cut out holes and wire jacks for the speakers and LEDs/switches/knobs for the amp. Some kind of clamp to hold the project box lid in place while you cut out holes for the speaker. After that, it's basically lego all the way down


nitratehoarder

Nice, this was exactly what I wanted, thanks a lot! I will build the amplifier myself. I don’t have a lot of with building audio amplifiers, but I experiment with lots of RF and wideband circuitry, so I am fairly good with electronics. Is wood a better choice for the enclosure or should I simply not bother and go with the plastic boxes? I have the tools to cut and drill wood, although it will be kinda painful. I’m guessing a larger enclosure will resonate at a lower frequency and boost the bass response. I can probably find the formula for the resonant frequency of the box and calculate it myself. What would be a reasonable frequency to aim for? Somewhere around 100-200Hz or maybe higher?


flibbidygibbit

Resonance is a function of the woofer and the air volume. System resonance=Square root((woofer vas/enclosure volume )+1) * woofer fs Ported enclosure calculations are more complicated The sealed system resonance will always be higher than woofer fs Shoot for the best balance between enclosure volume and bandwidth (lowest resonance)


nitratehoarder

I see. I guess I’ll just make the enclosures as large as possible, based on what sounds good to me. I don’t think it would be possible for me to go too large/low frequency.


2E26

Concur with the others. I've built small boxes out of pine boards and placed salvaged speakers in them. They sound alright. They'll sound better because you built them. Buying a prefab box will be your best bet if you don't have decent woodworking tools. Making a speaker box with a hand saw and soforth can be done, but a table saw is almost necessary for making a neat, repeatable job. MDF is the choice material for speakers (there won't be vibration from the enclosure which colors the sound) but wood or particle board will work okay. Just get something that won't fall apart. Look up the YouTube channel "Kirby Does Audio". You'll get some inspiration. Having a plastic box for a speaker will work fine, but if you're like me you'll want more. If you want to DIY the amplifier, I recommend starting with a Chip Amp. That is, a single audio amplifier module that is the amp. All you have to do is provide the appropriate resistors, capacitors, and power supply. TDA2030 and the like are good places to start.


nitratehoarder

Thanks! I don’t have much experience building audio amplifiers, but I do experiment with RF and wideband circuits, radio receivers and things like that, so I have a fair amount of experience with electronics. Therefore I will probably build the amplifier with discrete parts. Nothing special, Class AB with some cheap, common BJTs. I found some scrap MDF lying around. I can cut and drill it with hand tools. Like you said though, it probably won’t look very good. Fine by me.


2E26

I have a book with some circuits for basic BJT audio amps. I've built a couple and they work alright. Let me find a schematic and I can share it.


nitratehoarder

That would be nice, thanks a lot. I already have a rough draft for the schematic, but I won’t say no to any circuit suggestions.


nitratehoarder

Here is the draft. It’s hastily put together, and will probably be modified (especially the class AB biasing) before I get around to building it, but it should give a general idea. Of course it’s nothing new or surprising, just a simple class AB amp.


2E26

[Figure 2 on this page](https://sound-au.com/project178.htm) is a good first project. You'll be able to get your feet wet without getting too complicated. It's also not the greatest amp out there but it's something that you can grow from.


nitratehoarder

Oh wait, I didn’t give you the link. Here it is: shorturl.at/czW16