Speaker Evaluation

About a year ago I built my first pair of speakers. I built them alongside several other Penn State AES members. Basically, the enclosures are made out of PVC pipe that's been spraypainted black. We installed the drivers, made the crossover, and then put it all together. It took about 10 hours.

Since these speakers were made by us students, there was no frequency reponse information (think speaker stats). Fortunately, I have recently started working for a company who specializes in sound and vibration measurement. So, this past week, I was able to take some equipment home that would evaluate my speakers for me! Here are the results for the right speaker. (Click on the picture to get a close up view)



Now, each speaker has two drivers: a woofer (for mid-range frequencies) and a tweeter (for high frequencies). The blue line represents the response from the woofer and the red line represents the response from the tweeter. The crossover circuit was designed to make frequencies below 5 kHz go to the woofer, and above 5 kHz go to the tweeter. (Hence the drastic drop in the blue line at 5 kHz)

Ideally, the combination of the two lines is flat. What that would mean in practical terms is that the speakers are equally reproducing each frequency fed into them--no frequencies are being "favored" or "shunned". Generally, you want all of the frequencies to be within about 6dB of each other. As you can see, the low to mid range frequencies vary up to 8 or 9 dB which is not very good, but also not suprising for a 6" driver. However, the mid to high frequencies are quite nice, something I already knew subjectively.

The equipment I had can also measure distortion, but I didn't have time to do this because my whiney roomates made me put my toys away because they wanted to watch TV. Maybe next week I'll have distortion meansurements up.