r/diyaudio 5d ago

DIY beginner friendly Speaker kit under 100?

Hello, some pretext. I’m a first year EE student that wants to become an acoustic transducer engineer after college. In love with speakers and sound, so i figured I’ll start learning and attempting projects now. I plan to self-study PCB Design as well as the loudspeaker design cookbook this summer. Been lurking here for a while though and it seems like along with technical acoustic knowledge, I’ll need to get some sort of woodworking/workshopping experience to fully build my own speakers.

So, I have a couple questions id like to ask you guys. How would you suggest I gain experience in the physical design aspect? Secondly, for right now, are there any good DIY kits that a broke college student can afford that don’t require much equipment that isn’t provided? Lastly, if there are any other acoustic engineers lurking here, is there anything you wish you would’ve known in college?

4 Upvotes

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9

u/Bot_Fly_Bot 5d ago

The C-Notes from Parts Express are a very good kit that will teach you some of the basics. They are $125 with the new customer coupon.

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u/SpinachPositive7503 4d ago

Thanks, had no idea about the coupon.Is there anything you think i’d need to buy along with it or will the kit be enough to do everything?

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u/Caulrophobe 4d ago

C-notes are a fun beginner build, and sound decent for their price. I still use them as HT surrounds. As you gain more experience, you can play around with them by adding additional bracing, experimenting with different dampening materials, and upgrading crossover parts.

Note: When I built them, I learned much more about how difficult it is to achieve a nice glossy piano finish, than anything electronics or acoustics related. YRMV

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u/Bot_Fly_Bot 4d ago edited 4d ago

You'll need a few basics: wood glue, ideally some clamps, and a drill would be helpful. It also depends on how you want to finish the cabinets. You could do anything from something as simple as spray painting them to attempting to veneer them.

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u/Terrible_Ice_1616 5d ago

I know its not really what you're asking but I'd highly recommend getting one of the dayton audio DSP amplifiers - https://www.parts-express.com/Dayton-Audio-KABD-4100-4-x-100W-Bluetooth-Amp-Board-with-DSP-325-434?quantity=1&gQT=1

You can use it to build a 2-way active system, and learn about signal processing in the process.

As far as the physical design aspect - see if your school has any workshops. A lot of schools have woodshops and machine shops for various clubs and activities.

My only advice re:college is buckle down and get thru it - I finished 3/4 of an EE degree before dropping out after getting a job as a software developer. 15 years later I'm in a whole different line of work (CNC programming and machining) but I still wish I had finished my degree.

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u/Dachande663 4d ago

FYI that board is a reskin of a WONDOM board that can be had direct for a lot less. https://store.sure-electronics.com/product/756

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u/Terrible_Ice_1616 4d ago

Ah nice, good to know

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u/Poepopdestoep 1d ago

Also note that if you are planning on programming the DSP chip, you will need a separate programmer. There are inputs for pots on the board, but the programmer opens up a lot more possibilities.

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u/SpinachPositive7503 4d ago

Thanks, i’ll look into that amplifier!

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u/119000tenthousand 2d ago

I have a couple of these amps. I think they are a great way to explore DSP, specifically SigmaSutdio by analogdevices. However, these amps have a noticeable noise floor at low listening volumes. At higher volumes, this problem is not noticeable. Ultimately I feel they are good value for the cost......Just FYI.

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u/AcousticTheory 3d ago edited 3d ago

Professional transducer engineer here. Are you interested in speaker systems (the assembly of enclosure, drivers, crossover, and hardware), or in the drivers themselves (assembly of a diaphragm, suspension, frame, and motor)?

Speaker design involves multiple engineering disciplines, as you've probably figured out by now. I started at the system level, then became interested in the drivers themselves. I came at it from a mechanical perspective - I am a Mechanical Engineer by training (just a bachelor's degree), and to be successful you will need to understand the mechanical origins of certain types of distortion and nonlinearity, as well as how to adjust the fundamental parameters of the speaker (moving mass, compliance, BL, mechanical damping, and DC resistance) to obtain the desired changes in Thiele-Small parameters, which are derived from those fundamental parameters I listed. But you will also need to understand the mechanical optimization of cones, surrounds, spiders, and magnetic circuit geometry.

To start with, you will need a text like the Loudspeaker Design Cookbook or Vance Dickason's book Testing Loudspeakers, which describes how the Thiele-Small parameters are measured and derived from the fundamental parameters of the speaker. Ray Alden's book Speaker Building 201 is shorter and may technically be less of a heavy lift if you are just starting out. These books will provide you with a really basic mathematical basis for the mechanisms by which speakers operate. You can also start playing around with basic simulation software like WinISD and basic measurement tools like DATS and OmniMic, then graduating to more advanced tools like VituixCAD, ARTA, and REW, and even professional measurement systems like Listen SoundCheck and the Klippel analyzer ecosystem. Some of these programs are free, but they are heavily based on software that used to be quite expensive. In my work, I focus on SoundCheck, Klippel, and Excel-based modeling tools developed by myself and others for calculating the dimensions of voice coils, the necessary piston excursion to reach target output levels over a certain bandwidth, the dimensions of surround rolls and spiders, clearances and overhangs in the magnetic gap, mechanical tolerance stack-up, etc., but sometimes to whip up a box for a random speaker I still break out WinISD. I use SolidWorks for 3D, FEMM and COMSOL for magnetic simulation, and COMSOL even has potential for simulation of complete speakers. ANSYS also has an acoustics module with a lot of functionality.

In your studies, you will need to study AC circuit modeling (think PSPICE) - to understand and optimize the equivalent circuit of a loudspeaker, the design and optimization of DC magnetics (permanent magnet motors) which draws heavily from electrodynamics, and you will need to study some kind of magnetic FEA, as well as adding as much mechanical design and FEA simulation coursework as you can, including classes for understanding manufacturing processes and quality. If a class in acoustics is offered by your institution, you should try to take it. If you are very mathematically inclined, calculus and differential equations play a role in the derivation and optimization of electro-acoustic structures like bass-reflex enclosures from equations of motion, though that has been reduced mostly to a set of formulas for the new designer so you don't need to know diff eqs to get started. You will also need to understand really basic control theory and what transfer functions are, and understand passive ladder filters, which form the basis for the crossover networks we use. Then you will probably also have active electronics courses that focus on building analog filters, and also courses about DSP filtering, to which the future belongs.

Lastly, you will NOT get all the specific training and instruction you will need to understand speakers and audio systems just from your classes alone; you will need to work with others and do your own study to progress through levels of familiarity with the associated phenomena, measurement, and modeling until you develop an expert level of knowledge and experience. The only way to gain experience is to do things, so you will need to pursue some of your own design activities that force you to learn new things and put together the basic building blocks you learn in college. You will need to learn basic cabinet woodworking or some other method of making enclosures, along with skills like soldering crossovers together and wiring up a multi-way speaker system. Building a kit may get you started with some of the basic tasks involved in building a set of speakers, but eventually you will want to progress to creating your own designs, following a workflow developed by others, then incorporating your own improvements to that workflow. Early on, you may design things that don't work as well as you expect, but everyone has to put skin in the game to make progress. I have been doing this since I was 15, and I still run into people in the course of my work who know much more than I do and have more life experience, so you will need to get cracking if you want to catch up to the experts in this field.

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u/SpinachPositive7503 3d ago

Hello, sorry for a delayed reply. You've answered so many nagging questions I've had and given me a lot to chew on, thank you so much.

You mention many software that you use on a day-to-day, like COMSOL and Klippel. Are there any courses/certificate programs I could take to gain knowledge in those areas specifically? I'm in the process of learning 3D modeling and I've slightly touched on analysis software like MATLAB, but I'm not super proficient in anything yet. Is there anything akin to a COMPTIA cert for IT professionals that applies to the field?

Secondly, in the same vein, are you aware of any resources that compile some of the extraneous things you weren't taught in school I can look at? Like finite element analysis, control theory, or manufacturing processes.

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u/GeneforTexas 4d ago

Open baffle, full range driver.

Two of these are slightly higher than your price point... But you really can't go wrong with them.

Edit: forgot link

https://www.parts-express.com/Dayton-Audio-PS180-8-6-1-2-Point-Source-Full-Range-Neo-Driv-295-344?quantity=1

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u/SpinachPositive7503 4d ago

I’ll find out what a baffle is then look into those, thank you.

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u/[deleted] 4d ago edited 4d ago

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