Now on to the fun part! Being the creature of habit that I am, I started out with the 1997 version of the IASCA test disc. I skipped through to track 5, "The Vikings from Pomp & Pipes." Fourteen seconds into the track the organ starts with a tremendous amount of low frequency energy. The fundamentals should be felt more then heard. My fear of insufficient low frequency extension from the SA-100 subwoofers in a sealed enclosure was confirmed. They were not able to reproduce this low frequency information with any authority. However, the drum beat 20 seconds into the track had a solid impact. I strolled through the other tracks on this disk. Each time I was satisfied by the impact that these subwoofers had on musical tracks. However, when you switch to something with a lot of low frequency energy (below 40 Hz) then it was easy to drive them into audible distortion at fairly low levels. Overall sound quality was a little lacking. I sampled through a Johnny Lang CD, "Save the Last Dance," and Crystal Method's "Vegas" briefly after this. With musical information this is a reasonably capable subwoofer in a sealed enclosure, but not the most musical in this application. The larger sealed enclosure offered marginally better low frequency response. However, excursion limited power handling was reduced along with much of the impact. In the .75 cubic ft. per driver enclosure in-car response was down 6 dB at 25 Hz and down 3 dB at 63 and 80 Hz with an 80 Hz low pass filter at 24 dB per octave. Maximum SPL for the pair of subs before audible distortion was at 119 dB in the smaller enclosure. The smell of voice coils getting hot was quite noticeable at this point and I ended the evaluation of the subwoofers in sealed enclosures.
Now it was time to try out the vented enclosure. Since the RTA was already out I decided to measure frequency response first. The frequency response in the ported enclosure was not as stable as it was in the sealed enclosure, but it was at a much higher level with 25 Hz being 3-6 dB down; flat from 31.5 to 40, 50 Hz 3 dB down; and 63-80 Hz being 6 dB down. That was kind of surprising to me after modeling the enclosure. It turned out with other source material these deviations were not noticeable.