Wednesday, October 17, 2018

Getting Your Feet Wet in DIY Speakers

Preface 

Building speakers is so fun and rewarding. I always get a thrill when I turn on a movie or music and hear my creations again. How awesome is it to tell people “I built that!”? If this sounds awesome then you are in the right place.

In this edition I will outline several ways to get started. What works best for you depends on how deep you want to go. Are you wanting to jump in the deep end or just get your feet wet?

I tried to come up with a step by step plan so anyone can design their own speaker. The problem with this approach is that everyone is on their own path and at different skill levels. So, one plan won’t work for everyone. The best way I have come up with to help the most people is just show how I went about a recent build. This will show you what all is involved. Then you can decide how much you want to undertake. I will also suggest two kits you can buy to make this much simpler. Many people start with a kit. They include everything you need including precut wood so you don’t even need power tools.

Everyone will have a different objective. This guide will not address them all. Instead I will pick one and walk through how to complete it. Even if your goal is very different the steps needed to get there are similar. In this case I have the goal of making very good sounding speakers for $100 or less. These will be used for computer speakers. So, I need them to fit on a desk. Also, I don’t want to have to use a subwoofer do to lack of space and cost.

Goals list:

1.       Small desktop size
2.       Less than $100
3.       Great full range sound

I have three different designs that loosely fit our goals. The first two designs are perfect for anyone that doesn’t want to do wood working. While I love wood working, I know it is not for everyone. Several top designers always have someone else build enclosures for them. They just don’t like to do it.

Speaker kits:


Overnight Sensations
I will start with the one that doesn’t quite fit my goals. That is because it is the most expensive at $138: This speaker was designed by Paul Carmody. It lives up to its name. I heard this at an event where I met Paul. And I have built several of these kits. All the pieces for the box are cut perfectly. It is almost fool proof. I say almost because by brother assembled and painted them – badly. As a tip the box need to be sealed. The edges are rabbited so that the pieces almost lock together forming a sealed edge. How you can leave gaps in the seams is something only my brother could accomplish. Luckily silicone caulk seals very well.  So after a bit of magic they worked fine. 

The next speaker is also from Parts Express. The C-note kit is the same basic setup as the overnight Sensations. As its name suggests it is $100. I have not used this one. I included it because it has the same goals as I set out.


Dayton 4

Last is my own design. I will outline how I went about it. I will do my best not to lose anyone. Think of this as the Cliff notes version. I will cover the programs I used in detail in future blogs.

I failed at my first attempt to build this. The woofer wasn't up to the challenge. This will happen if you are in this hobby long enough. Later, at a DIY speaker event, I had the opportunity to hang out with two of the people that work for parts express. They were talking about a new driver that they had just gotten in, gushing about it more than anything. And it is only $12. I looked at it and thought of the failed speaker I had given up on. It was a perfect drop in replacement. And it worked wonderfully. Everything seemed to fall into place after that. I call it the Dayton 4. Because I'm really bad at naming things. 

The Drivers

Dayton Audio ND16FA-6 5/8” tweeter – This is a tiny press fit tweeter. Just cut a hole with a 1 1/8” hole saw. Press it in. Done! Frequency response 3500-27000hz.

Dayton Audio TCP115-4 4” woofer – The budget woofer that can do everything. Very easy to design with. Frequency response 53-5000hz

A screenshot of the parts needed for a pair.


The Enclosure

The enclosure is 8” tall, 6”wide, and 8.5” deep. Made out of ½” plywood or MDF. I built a triangle port that caused some minor issues. Instead I recommend a 1.125”diameter port tube 6.5” long installed on the back behind the tweeter. You can find one here.



Test fitting drivers

The Crossover

The crossover is the brain of the speaker. It directs the sound to the correct driver. High frequencies go to the tweeter and lower frequencies to the woofer. This is can make or break a speaker. It is the hardest part to get right. I use a calibrated microphone to measure the drivers once I have them installed in the box. Then I import the results to XsimXsim is a free program for modeling speakers. I used a series crossover. This type of crossover is not used often because they are hard to work with. I this case it worked very well with only 4 components.
Schematic for Dayton 4 Crossover




How do they sound?

This is the tricky part. They are my babies; So, I am very biased. They have a great frequency response of 48 – 27000hz. This doesn’t mean anything to most people. But that is very good for any small speaker. And unheard of for one that costs about $30. Treble is airy. Bass is amazing for a speaker this size. Listening to it puts a smile on my face. And that is my ultimate test. 
Cat approved!


All Photos by the author.

5 comments:

  1. I really appreciate your use of pictures in your posts. It makes it so much easier to follow. I had no idea that people made their own speakers. How long does it usually take you, from start to finish?

    ReplyDelete
    Replies
    1. Thank you JWiess,

      I have built a set of speakers in less than a week. I have no idea on how many hours it takes. Some designs take much more time, depending on complexity. These were done in just a few days. (I had the boxes already built.) I have others that have been set aside for years that may never get finished.

      Sorry about the late reply. I need to see what is going on with my notifications.

      Duane

      Delete
  2. Thanks for the simple description. I LOVE building speakers. I have built more pairs that I can count. I've built 2-ways, 3-ways, and single-driver speakers. As much as I love building them, I just haven't been able to wrap my head around designing crossovers. I can use WIN ISD pretty well and I can read a schematic and build a crossover. I've had a lot of electronics training, military and civilian, but crossovers just don't click for me.
    So, with all that being said, almost everything I have built is someone else's design. I'm actually fine with this. There are a lot of very savvy designers willing to share their expertise, so I'm willing to follow them and try their projects.
    I'm looking forward to seeing what might be posted and adding my input, for what it's worth. I hope no one here will overwhelm people looking for ideas. I hope no one will discourage others from trying something new. I've seen, on some of the forums, new folks looking for simple advice get lambasted with theory so deep they give up and buy speakers from big box stores. That's sad. The write-up on your speaker was very easy to follow and not overwhelming.
    Thanks for starting this forum!
    Mike

    ReplyDelete
    Replies
    1. Thank you Mike. My goal is to give fundamentals without all the little stuff that doesn't make much of a difference. I plan to go over crossover design next. That is one of the hardest things to get right. But, it is the key to making a wonderful speaker.

      Delete
  3. Good to hear. Looking forward to it Duane.

    ReplyDelete