Hello everyone. I have finally decided to post my design for a simple, high value 2.1 system that can be adapted to many uses. It uses all Parts Express available parts and is only $300 for everything including speakers, amp, boxes, terminal cups and XO parts. The only thing you need to add are paint (or veneer) and wire.


These speakers resulted from a free pair of PE's 0.04 cu.ft. KD boxes that I got from Paul W. after he "won" them at the Scott Q's SEC DIY event in late 2012. He didn't have a use for them, but I thought I could use them, so I asked if I could have them and he gave them to me. After a little thought, I came up with this design. It uses the new DS90-8 budget speakers and a ND16 tweeter. To this I added another PE Knock Down 0.23 cu.ft. box, the PE 2.1 plate amp and a Tang Band W6-1139 SIF woofer.
This is one of those serendipitous moments were everything just came together naturally. I could use off the shelf boxes, speakers and crossover parts and get an excellent sounding system for a very reasonable cost. After much experimentation, I ended up with this frequency response as measured in room from one meter with no windowing:

This shows both 1/3 octave smoothing and one octave smoothing together. Darn near flat from 40 to 20k.
Now here is where I add my confession. I did not use XO design software. This is a case where I just measured individual speaker responses and applied XO parts as needed. I used a good dose of experience and some help from "textbook" notch filters. But I think you can see that the results were spot on.
For now, this is the only XO diagram I have. I hope you can read it. I will try to come up with something more "professional" a little later.

The object was to use off the shelf parts and as few as possible to get the job done. Space is very limited in these tiny boxes, so everything had to fit, so that's why I used PE's project box circuit boards and 5 rather than 10 watt resistors. After all, the amp is "just" 20 watts per channel. But this is more than enough and drives these little boxes as loud as I want.
The name is simply an acronym for Part Express Desktop Speakers. I had originally intended for them to be desktop speakers, but they turned out so good, that I use them on freestanding speaker stands as my everyday drivers in my home office. I have used them probably eight hours a day for nearly a year now and made a few minor updates. They run off the headphone output on my laptop, so nothing else is needed. I haven't tried it yet, but I guess you could run them off your phone if you wanted to. The XO diagram shows you the original XO and also the optional L-Pad options for the tweeter. At this point, I am using the +1 and 1/2db option which I find gives it the best response in my room and with my old ears.
As I go along on this build thread, I'll explain my choices. But if you are interested, the KB boxes are all on sale now, so grab them if you think this would fit your needs. I'll post a full parts list in a day or so when I have the time, but I used PE's project box circuit boards to keep it simple and I used all PE XO parts.
I hope someone will build these with the veneered boxes they deserve. I have a couple of other speakers in development, but I keep coming back to these for everyday use. They are exceptionally neutral and image well beyond what I expected. And now as they are fully broken in, the level of detail is simply amazing for the price. But what really does it for me is the bass. The bass bin is so small that you can hide is virtually anywhere and the Tang Band woofer is a wonder. I was blown away when I heard solid 40 hz bass from this shoebox sized woofer. The bass boost on the amp is a perfect match for the sealed woofer. I used to think that a 60 hz cutoff was sufficient for a stand alone box, but this changed my opinion. I now think that you either go to 40 hz or you are not hearing what you need to.
Let me know what you think. That's all the time I have tonight, but I will answer questions as I can and post more details later. I hope this is something that will fill a need for some of you.
-Bob
p.s. As always, this is free for non-commercial use, but commercial use requires my permission.


These speakers resulted from a free pair of PE's 0.04 cu.ft. KD boxes that I got from Paul W. after he "won" them at the Scott Q's SEC DIY event in late 2012. He didn't have a use for them, but I thought I could use them, so I asked if I could have them and he gave them to me. After a little thought, I came up with this design. It uses the new DS90-8 budget speakers and a ND16 tweeter. To this I added another PE Knock Down 0.23 cu.ft. box, the PE 2.1 plate amp and a Tang Band W6-1139 SIF woofer.
This is one of those serendipitous moments were everything just came together naturally. I could use off the shelf boxes, speakers and crossover parts and get an excellent sounding system for a very reasonable cost. After much experimentation, I ended up with this frequency response as measured in room from one meter with no windowing:

This shows both 1/3 octave smoothing and one octave smoothing together. Darn near flat from 40 to 20k.
Now here is where I add my confession. I did not use XO design software. This is a case where I just measured individual speaker responses and applied XO parts as needed. I used a good dose of experience and some help from "textbook" notch filters. But I think you can see that the results were spot on.
For now, this is the only XO diagram I have. I hope you can read it. I will try to come up with something more "professional" a little later.

The object was to use off the shelf parts and as few as possible to get the job done. Space is very limited in these tiny boxes, so everything had to fit, so that's why I used PE's project box circuit boards and 5 rather than 10 watt resistors. After all, the amp is "just" 20 watts per channel. But this is more than enough and drives these little boxes as loud as I want.
The name is simply an acronym for Part Express Desktop Speakers. I had originally intended for them to be desktop speakers, but they turned out so good, that I use them on freestanding speaker stands as my everyday drivers in my home office. I have used them probably eight hours a day for nearly a year now and made a few minor updates. They run off the headphone output on my laptop, so nothing else is needed. I haven't tried it yet, but I guess you could run them off your phone if you wanted to. The XO diagram shows you the original XO and also the optional L-Pad options for the tweeter. At this point, I am using the +1 and 1/2db option which I find gives it the best response in my room and with my old ears.
As I go along on this build thread, I'll explain my choices. But if you are interested, the KB boxes are all on sale now, so grab them if you think this would fit your needs. I'll post a full parts list in a day or so when I have the time, but I used PE's project box circuit boards to keep it simple and I used all PE XO parts.
I hope someone will build these with the veneered boxes they deserve. I have a couple of other speakers in development, but I keep coming back to these for everyday use. They are exceptionally neutral and image well beyond what I expected. And now as they are fully broken in, the level of detail is simply amazing for the price. But what really does it for me is the bass. The bass bin is so small that you can hide is virtually anywhere and the Tang Band woofer is a wonder. I was blown away when I heard solid 40 hz bass from this shoebox sized woofer. The bass boost on the amp is a perfect match for the sealed woofer. I used to think that a 60 hz cutoff was sufficient for a stand alone box, but this changed my opinion. I now think that you either go to 40 hz or you are not hearing what you need to.
Let me know what you think. That's all the time I have tonight, but I will answer questions as I can and post more details later. I hope this is something that will fill a need for some of you.
-Bob
p.s. As always, this is free for non-commercial use, but commercial use requires my permission.
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