Class D?

Among all the passionate discussions taking place on audiophile sites I found that I need to find a sweet point between the money, effort I put in my project, the fun I can get working on it and result (in terms of sound quality) I can get at the end.
Since I'm just an ignorant hobbyist I don't see a point to invest too much in my first project. I want it to be both fun and challenging.

So my amp is going to be fully digital class D amp. No analog circuits at all.

The roadmap is:
1. Play music on a device which has a USB
2. Convert USB to I2S
3. Pass I2S to PWM modulator
4. Feed power stage with PWM from the modulator.
Seems not to be super extremely complex.

I found these nice chips from Texas Instruments:
-  PWM modulator TAS5548
- 300W/channel power stageTAS5631B
last one promises pretty good THD up to 100W, but I don't think I ever need that power, especially having active amplification.
TAS5548 can processes 8 separate channels (4 I2S stereo channels) at 96kHz, has two ASRCs onboard and 7 biquads per channel. So it is able to handle all active crossover filters! I like the idea.

So next step is to design a PCB.

Two speakers test

Well, two speakers sound much better than one.
After playing with miniDSP settings I found the most sweet crossover point at about 1800Hz 24db/oct Linquitz-Riley.
Acoustics in my room is far from ideal so it affects my experience. I wish I had more lows but for some reason I hear them much better in the other room. Polarity change doesn't help.
Also I've decided to go with 3-way, I feel 1800 Hz is not the best crossover point for both tweeter and 8" woofer.

Now it is the time to think about new amplifiers. Mine don't drive 4 ohm (XT25 are 4 ohm) and I don't want to put resistors in series with my tweeters. Some people say that is a bad idea and I would agree...

Welcome Home!

My family is about to get back from their trip.
I want to impress them.
Some el-wire, tape, and a poster board turned into this cool thing

UPD: They were really impressed! I rock!

The First Speaker Is Ready For Testing

Here is my first four feet baby box:

It sounds good. Way better than a crappy Pioneer speaker or a couple of Chinese Acoustic Art I have. But one speaker is not enough for a good listening test.
I think I need to build a Wallin's Jig to measure my room and drivers.

MiniDSP 2x4

I got my drivers and MiniDSP 2x4 kit.
MiniDSP has a nice looking crossover management software.

While I work on my boxes, drivers have time to warm up.

First enclosure is almost done

One of the enclosures is almost done!

Someone can ask me why I placed drivers too far from each other. Well, the only good answer I have is "what if I want to add a midrange later?"
MiniDSP should help with signal delays.

Woodworking

Time to have some fun with MDF and tools!

MDF sheet didn't fit into my car so I had to cut it in store. Both Lowes and Home Depo have the same crappy saws and I was afraid they can't cut it precise enough. Well, I ws absolutely right.
Thanks my colleague Mike - he has a table saw and he helped me to trim all the pieces to be the same width.

After I had all the pieces cut and holes routed I could start to glue it all together. I decided not to use any screws because if I veneer it later screw heads can be visible even covered with putty.

Don't think I would make a sandwich like this next time. It is really hard to position parts right

Drivers fit pretty well:

I'm going to reassemble speakers many times so I put some effort and used t-nuts. I like the result.

By the way, Harbor Freight clamps did the job but I would not recommend them for any professional work. They are very cheaply made, but no one can beat the price.