Hello, my dudes!
There are so many different brands and types of drivers out there it can be really intimidating thinking you really only need to pick one. But that's what so great about constraints and all the planning work we did in step one.
Download the Worksheet
(by the way, if you haven’t watched the step one video, pause real quick, watch that video, then come back. Everything will much much more sense if you do.)
In step one we got a clear idea of what we want and don’t want from our finished speakers and we answered two important questions.
The particular project we’re working on for this series will be in either a ported or passive radiator designed enclosure and it’ll use a 2-way crossover to deliver sounds.
We also have our lists of constraints and goals.
- Dayton Audio Components
- 2 Channel Stereo
- Smallish Enclosure Size
- 50 Hz Low End
- 2 Woofers
- Thin Front Baffle
- Simple Construction
There are 7 things I like to keep in mind while picking drivers.
- Goals & Constraints
- Enclosure Size
- Crossover Type
- Frequency Range
We answered most of these in step one and with that information we can pretty quickly cut out a large portion of the drivers on the market.
So let's go through the steps and compare the relevant ones to the work we did in the last step.
The relevant steps are 1-4
Goals and constraints - We’re just going to reference them from The Plan
Enclosure - I want a 5” front baffle, which means my woofers can’t be over 4”
Crossover Type - This is going to be a 2-way system, so I know I’ll be adding a tweeter. So I’m looking for a mid-woofer, not a full-range woofer.
Budget - I need my woofers to be at a certain price.
So we use this information to narrow our prospects.
One of my design goals for this project is to have a fairly thin front baffle size of around 5”. And this constraint alone cuts out all the drivers that are larger than about 4 inches. I also only want to use Dayton Audio brand drivers, boom, another huge cut.
I went from about 447 woofers to choose from to about 24 with only two constraints. And when I factor in my budget, it lowers it again to about 10 drivers.
Remember in the last video when I said constraints are good? Well, here's the first example. Constraints bring focus.
Now it's nice to narrow your prospects, but you may get to a point where you get too narrow and you aren’t able to meet your higher priority goals with the constraints you’ve given yourself.
At that point, you can either change your goals to meet your options or cut back on your constraints to widen your choices.
We can now use the rest of the steps to select my woofer.
Frequency Range - I compare each drivers frequency range. I know I’m going to add a tweeter to the system and tweeters normally handle down to about 1000 to 3000 Hz. So I’m looking for a woofer that can handle frequencies above 3,000 Hz.
Now if for whatever reason I get my heart set on a woofer that can only reach up to 1,000 Hz or less, I’ll need to make sure I select a tweeter that can meet that range. This is the main factor for choosing a driver, so spend some time on this one.
Sensitivity - Sensitivity is really important, but it can be modified in the crossover later on. A good sensitivity match right now means fewer components in your crossover later on, which is a good thing. These speakers are going to be in an MTM configuration, with two woofers and one tweeter. So I want to make sure the tweeter is more sensitive than the woofers. Making the one tweeter able to be just as loud as the two woofers.
Looks - And last is you may want your drivers to look good.
Using these three factors I’ve narrowed my choices in woofers down to two drivers: the Dayton Audio DS90-8 3” mid-woofer, which I’ve used before and like, or the new Dayton Audio TCP115-8 4” mid-woofer.
I’m going to move forward with both, basically splitting my one project into two, and see which one I end up liking better in the computer models.
This is how a lot of my designs start, with multiple driver ideas for the same project, and then its the survival of the fittest.
The same process goes for tweeter selection. Use your project constraints to narrow the selection pool and start looking at specs.
I made a video a few years ago going through the 7 steps of selecting drivers for your project.
Watch the video here.
Frequency response is probably most important here. Particularly the low end of the frequency response. like with the woofer, you want to make sure the low-end response of your tweeter is lower than the high-end response of your woofer.
Later on, we’ll talk more about crossover design, but you’ll need some overlap to play within that step.
I’m pretty sure I’m going to stick with the Dayton Audio TD20F-4 3/4” tweeter. It fits my budget, the frequency range is right where I want it, and it looks nice. This might change later, but I’m going to use this tweeter for my models on both woofers.
Alright, that's selecting drivers for this project. Just remember this whole process is iterative. You can go back forth through the steps and make changes if something isn’t working out. You’re not stuck with what you select in this step. Unless you place the order for the parts right away, then I guess you are stuck.
On the next video, we’ll get down and dirty with our first software program and design our enclosure. I’m hoping that’ll be out next week.