By changing these inserts, we are changing the amount of magnetic force (Bl) applied to the voice coil. The Low Q insert is the largest and it produces the highest Bl product. Having a higher Bl product means you have more available force to move the cone, but it requires a more powerful counter force to help control the movement of the cone. By going to a smaller enclosure, we have a tighter or stiffer air spring that the woofer cone is working against. As the Q of a subwoofer goes up, the Bl factor drops and you need a larger and larger enclosure to soften the air spring. If you do not soften the air spring, the stiffer air spring will start to override the ability of the motor to properly control the movement of the cone, resulting in higher distortion and possibly damaging the sub. So as I am raising the Q of the 12d VQ, I will be expecting some pretty obvious changes in the sound quality because we will be moving radically away from the correct size enclosure.
I installed the Low Q magnet insert to begin. With this insert the 12d VQ should be optimized for the 0.7-ft3 enclosure that we are using. It sounds really tight and punchy, and hits hard.
I pulled the Low Q insert and installed the Mid Q one. The bass is now a bit looser. Not as tight, but the low frequency extension does appear to be slightly better. The power handling also has taken a step down. So now I go for the High Q setting by removing the insert altogether. First impressions were that the overall efficiency was now lower and that the bass impact response had radically changed. It was just out and out loose, with a lot of hangover. The power handling was way down and the woofer was just screaming that it was in the wrong enclosure, which of course it now was. Well, what do you know, this adjustable Q thing does work. Awesome! One subwoofer that can be tuned to match many different applications-I am getting excited.
OK, enough playing around, let's get to the listening! I reinserted the Low Q plug and mounted the 12d VQ in the enclosure the correct way. Then I cranked up Lenny Kravitz's album Lenny, track five, "Believe In Me." This track has a great opening bass line and a tightly recorded drum kit that will really exercise a subwoofer. At 80Hz the 12d VQ is loud and delivers chest-pounding impact. From 60Hz and below, the loudness level of the bass line falls off slightly. The 12d VQ definitely has a hump at about 80Hz and can tend to sound a little one note-ish. But the 12d VQ is not muddy like some of the other subwoofers that I have tested. I tried a number of tracks quickly and decided to try the 12d VQ in a larger enclosure, a 1.0-ft3 sealed.
The results were immediate. The upper bass hump is now much smoother and the low frequency extension is greatly improved with this slightly larger enclosure. The 12d VQ produced impressive impact and clarity. Imaging is good and mostly up front.
Next I listened to Sade's Lovers Rock album, the title track. This track has a bass line that moves from 80Hz to below 40Hz, and the upper frequency bass note hump is again noticeable, but not overpowering. A touch of equalizer, a slightly larger enclosure or possibly lowering the crossover frequency may correct the response curve. From 0:53 to 1:00, there is a declining scale of bass notes. The 12d VQ reproduces these note changes with authority and ease. It has excellent impact response and gave me a good shaking.
Next I put in 10,000 Maniacs' "Peace Train." The opening eight bars of this track have a deep 30Hz kick drum beat, one beat per bar. It's perfect for highlighting subwoofer impact and hangover, if there is any. The kick drum impact is very firm but it is missing the really deep fundamental note. Hangover is again minimal and the overall performance is great.
Next up is Creed's Human Clay album, track four, "Say I." After about 20 seconds, I found myself thinking that the 12d VQ is geared for rock music. The bass line came through super fast and tight. A lot of kids that I work with are asking for subwoofer systems that have "fast bass." Well, the Infinity 12d VQ has moved to the top of my list of recommendations.
I finished off with a listen to the title track off an old favorite album, Harry Connick Jr.'s We Are In Love. It features a fine recording of a closely mic'ed stand-up string bass. The bassist is getting a workout in this recording, going up and down the scale. The Infinity Perfect 12d VQ reproduces the attacks of the string plucks with great authority. I could feel them in my chest, and the note shifts are clearly defined and controlled.