Active speaker DSP test bed -- enough interest?

[Sydney]

... I don't think I'll ever be "done" with any of the articles--I always go back and rewrite things, especially if someone provides comments....

With that in mind in the book "The Design of Active Crossovers" By Douglas Self has some good reference material in chapter1: Crossover Basics on the advantages/disadvantages of Active Crossovers ( p 8 - 16 )

[ernperkins]

Great start with the first article Neil. Rod Elliot isn't the only one convinced of the advantages of active crossovers; this is from SL's website: "Crossovers may be implemented either as passive RLC networks, as active filters with operational amplifier circuits or with DSP engines and software. The only excuse for passive crossovers is their low cost. Their behavior changes with the signal level dependent dynamics of the drivers. They block the power amplifier from taking maximum control over the voice coil motion. They are a waste of time, if accuracy of reproduction is the goal."

[neildavis]

I've got drafts of the first 4 articles posted at www.audiodevelopers.com. I haven't gone back and edited, so there are probably lots of dumb errors and maybe some big ones. But it's a start.

[Kornbread]

I was doing ok till step 5. Krap, I was hoping to understand enough to use this.

[neildavis]

I was doing ok till step 5. Krap, I was hoping to understand enough to use this.

Yep--article 5 is where it gets complicated, but it's just a draft. I need to point out that there are two ways to control the DSP. One is using C code in the Arduino, and that is what that article currently focuses on. The other is to use ASD, which is my version of the miniDSP GUI. ASD will hide all of that tedious microprocessor code. ASD uses that Arduino code, but the user doesn't need to understand any of that bit-banging going on under the hood--they just need to load the Arduino with the right code. So I need to point out that the microcontroller article is only applicable if you want to take control of the ADAU1701 yourself with a local user interface.

I'm at a resting point on the articles because I need to update ASD. I need to fix some things that got broken recently, and I need to get it to work with all Arduino boards. Right now it only works with Arduino boards that have the FTDI USB chip, and there aren't that many of them. And I don't want to write the next article on ASD until I've got the code updated.

Hmmm...maybe I'll split 5 into two articles: one if you plan to use ASD and the other for those determined geeks who want to write their own code.

[TN Allen]

Thank you for doing this, I appreciate the clarity you provide, and plan to follow along and do the project. I have a little experience with Arduino and look forward to learning to do more using your project.

[bjaurelio]

I just took a cursory look at your website and am extremely excited. I've been mulling over an active design in my head for awhile now. We just moved half way across the country and are now in the process of buying a house that we hope to be in before the new year. Hopefully I can convince my wife that I should build an active stereo system next year to have a good music system outside the h/t room.

[evilskillit]

I just finished reading the PowerPoint and the whole thing is very interesting. I can't wait to see where it goes.

[Jonathan Anspach]

I'm very interested.

[Kornbread]

Wasn't there a download of ASD available somewhere?

[neildavis]

There is a somewhat old version at: http://www.audiodevelopers.com/Software/ASD/setup.exe. You can play with that version to get a feel for what it does.

I need to post a new version that has a lot of changes, but I've been waiting until I'm done updating the USB interface code. The original software was dedicated to the FTDI USB chip that was the defacto standard several years ago, and it was before Arduino boards were around. There is a newer version of the software that I could post that will work with Arduino boards that use the FTDI chip. But now most of the Arduino boards are using the Atmel chip, so I want to change the USB interface code to be more flexible and not dependent on the FTDI driver. I'm working on it...