We’re going to build a speaker together. 

Yep, we’re going through the designing and building of DIY bookshelf speakers, starting with this video and blog post. We wade into the water together with step 1, the plan.

So lets back up for a moment. This post is the beginning of a series of posts taking you through my design process for building speakers. I plan to do a number of these series on different projects, so you can see how the process stays relatively the same but can adapt to various projects.

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THE PROJECT

This first project is a set of DIY bookshelf speakers I’m calling Side-Fire. Though I haven’t yet come up with the specific design feature the name is referencing at this point in the process, that’s both getting ahead and behind myself.

The first step of designing, anything really, but specifically a speaker, is coming up with a plan. There are some specific questions we need to answer to move to the next steps efficiently.

1.) What will be the use of this speaker?

    Examples: Home theater setup, casual music listening, critical music listening, home theater and music listening, portable relaxed music listening

This design will primarily be used for music listening.

2.) Where will these speakers be used?

    Examples: Living room, bedroom, on a desk, outside

I want these speakers to have an extensive use case, from desk speakers to living room listening. So I’m going to write “general.” Specificity is best here, but this will work too long as it gets your mind thinking about the project.

CONSTRAINTS & GOALS

The answers to the above questions will now be used to decide design constraints and goals used in future steps. But there’s a good chance you’ve already been thinking a lot about this project. So let’s list these now.

Constraints

  • Budget

  • Dayton Audio Components

  • Unique

  • 2 Channel Stereo

  • Smallish Enclosure Size

I’m a big believer in limitation being the catalyst for creativity, so remember the more self-imposed constraints, the better. You can always cut back on restrictions down the line.

Goals

  • 50 Hz Low End

  • 2 Woofers

  • Thin Front Baffle

  • Simple Construction

Goals are like your wish list. What does this project look like in your dreams? The more specific, the better.

THE TWO DECISIONS

What you have so far is excellent information we’ll need to reference as we continue the design process. But there are two critical decisions we need to make right now: enclosure type and crossover type.

These two decisions don’t necessarily have to be final at this moment. You can decide now, go through the next few steps, decide you want to try something different, come back to a different decision, and move forward again. This step, like most of the design steps in the future, is an iterative process.

But we need to start with something, and using our constraints and goals, and we can usually narrow options down pretty considerably.

Enclosure Type

I’ve done a video on selecting an enclosure type that goes into some depth, but the most common enclosure types are: sealed, ported, or passive radiator.

So let’s start with sealed. Looking at our constraints list, sealed definitely works to help us stay in our budget because no port means fewer components. It also helps with our simple construction goal for the same reason.

BUT a sealed enclosure doesn’t usually have the bass extension that a ported enclosure can offer, and since we are looking for 50Hz low end, a sealed enclosure isn’t the best choice.

Now a passive radiator is a great choice when enclosure size is limited, and you are still looking for a good low-end response, so that’s a plus. The negatives of a PR is increased cost since you’re adding a component, you’re also complicating the construction a bit. On the positive, it can add to the uniqueness of the project.

This point is where your project priorities come into play and these are mostly personal to your project. In this particular case, I think I can still stay in budget while using a port or maybe a PR and I don’t think adding either will complicate the project enough to give up the low end.

So I’m going to stay away from sealed in this case and go with a ported enclosure or maybe use a PR design if my budget allows it. 

Crossover Type

I also have a video on selecting a crossover type, but some examples of crossover types are 1-way, 2-way, 2.5-way, and 3-way. With the most common being a 2-way crossover setup.

The number refers to how many times the audio spectrum is split. A 1-way or point source isn’t split at all; the full audio spectrum is delivered to the listener through one speaker. In a 2-way crossover, the signal source is divided into two frequency bands, the highs go towards the tweeter, and the lows go to the woofer(s).

Type of crossover selection is a pretty easy choice for me, and I’m going with a standard 2-way crossover. So I’ll be adding a tweeter to this project.

THE END

So that’s pretty much it for step one. Just make a plan! I hope I’ve added enough hardpoints and questions to make the outline of a project a little easier, but that gets you started!

Until next time!

-Kirby