Skip to main content

Subwoofer Box Design

Designing the box has been a very difficult problem. The math isn't complicated, and is easily done with a spread sheet, but unfortunately I can't seem to make the box as small as I'd like to. This, of course, is because I'm building a bandpass box. But, I'm more willing to compromise on the size of the box than I am to compromise on the type. Building a bandpass box means that I can keep my speakers enclosed and protected. I hope to make the box look inconspicuous and easy to pack stuff on top of. Having two exposed 10" woofers doesn't accomplish either of those goals very well.

So, I'll be using a 3-chamber bandpass with 2 sealed sections and 1 vented section. I'll have 4 slot ports on my vented section. Here are my calculations:

Box Calculations for Fl
Vas 101.14 l
Fs 30.5 Hz
Qts 0.445
S 0.7
b 0.7206
Fl 42 Hz
Fl' 0.6127868852459
Fh 91.3894382022472 Hz
Qbp 0.90392587983616
Fb 61.9544704157366 Hz
Vf 39.25536706 * 2 l
Vr 32.3528344267576 l
Pa 4.0904342524327 dB

Port Calculations
Dv 11.9896857473094 cm
Fb 65.5 Hz
Vb 78.51073412 l
Lv 31.4475560689208 cm
Np 4
k 0.732

These numbers do not take into account the volume of the ports or the speakers. Once they're available, I'll post drawings which will include the final dimensions.

Popular posts from this blog

Email Injection

Not so long ago, I ran a wiki called SecurePHP. On that wiki, there was one particular article about email injection that received a lot of attention. Naturally, with all the attention came lots of spam. As a result, I disabled editing of the wiki and content stagnated. Still, the email injection article remained popular. About a year later, the server that hosted SecurePHP died and I never had a chance to hook it all back up. I saved the article though and I'm reposting it now. It may be a bit old (I've been away from PHP for a long time), and I didn't write all of it, so feel free to leave comments about needed updates and corrections. Though this article focuses on PHP, it provides a lot of general information regarding email injection attacks. The PHP mail() Function There are a lot of ways to send anonymous emails, some use it to mass mail, some use it to spoof identity, and some (a few) use it to send email anonymously. Usually a web mailform using the mail() funct
Read more

XBee ZNet 2.5 Wireless Accelerometer

I managed to put together a wireless accelerometer the other night using my two new XBees, an Arduino XBee shield, an XBee Explorer USB, an ADXL330, and some Python. I struggled a bit with some of it, so here's what I learned: First, a parts list. XBee 2mW Series 2.5 Chip Antenna Arduino XBee (with XBee Series 2.5 module) XBee Explorer USB ADXL330 I'm not sure exactly what the specs are on the XBee that comes with the Arduino shield. But, it is definitely a series 2.5. The first thing to do is to configure and upgrade the firmware on your XBees. To do that, you'll need X-CTU (for the firmware upgrade at least, but it's also nice for configuration) which, unfortunately, is only available for Windows. But, it works fine from VMware. First up, the XBee we'll hook up to the computer to read incoming data from the accelerometer: Plug one of the XBees into the Explorer (it's also possible to do this from the Arduino shield by shifting the two XBee/USB jumpers to USB
Read more

MJPEG Streaming Protocol

MJPEG is a popular format for webcam streams. It's probably popular because it's so simple to do and the performance is surprisingly good. Unfortunately, I found it quite difficult to scrape together enough information to implement a streamer myself. In an effort to help the next poor, frustrated soul, here's a simple method for streaming an MJPEG to a socket in Java. public void handleConnection(Socket socket, JpegProvider jpegProvider) throws Exception { byte[] data = jpegProvider.getJpeg(); OutputStream outputStream = socket.getOutputStream(); outputStream.write(( "HTTP/1.0 200 OK\r\n" + "Server: YourServerName\r\n" + "Connection: close\r\n" + "Max-Age: 0\r\n" + "Expires: 0\r\n" + "Cache-Control: no-cache, private\r\n" + "Pragma: no-cache\r\n" + "Content-Type: multipart/x-mixed-replace; " + "boundary=--BoundaryString\r\n\r\n&
Read more