AutoTuba built to specs

[dheafey]

I finished building an AT for my daughter's boyfriend (hereto referred to as "junior") and last week we installed it in his 1999 Cadillac DeVille, powered by a Profile AP700M. Junior listens to a wide variety of music from heavy rap to Nickelback, so the challenge was to make the AT sound good on everything. After initially setting it up, I tweaked the amp and head unit to give a good overall thump to just about everything. A few days later, I heard it wasn't sounding as good as junior expected; long, synthesized bass notes were very good, but quick kick drum hits had the recommended MCM driver hitting Xmax. After going through the head unit, all the settings I worked on had been "cranked" to ridiculous levels. Last night, I spent an hour in the car and did the following:

- leveled out the AUX input (most of junior's music library is on his iPod) from +18 to around 10'ish. Send a distorted, cranked signal into the head unit and that's what you'll get out of the speakers. I also schooled him about good and bad quality MP3s.

- Dropped the SUB level from +8 to -2. Same as above: crank it and you'll get distortion (exceeding Xmax in this case).

- Dropped the BASS from +8 to +3 or so.

- Rotated AT 90 deg (from wheel to wheel to rear facing).

- Most importantly, taught junior about good, punchy bass vs. loud, distorted bass.

The latter, IMO, was the most important. Teach him about good sound and how to create it and he's much better off. Luckily, the kid's a sponge and listens. I told him to forget about his cousin with the dual 12" 1000W sub in an open Explorer that's loud and distorts like crazy. That was his yardstick and, luckily, junior is now a believer in folded horn designs.

How does it sound? Visceral is the word I'd use. Clean, loud, and punchy. I'm frightened to think what this thing would sound like in a hatchback or another open-space vehicle; in junior's trunk, we've found all the loose bolts and plastic pieces in the car. People freak when they find out it's an 8" speaker getting no more than 100 watts, but that's what innovative design will get you.

At about $100 USD to build and $150 for amp and wiring, you get one kicking sub; bang for the buck is unattainable with a conventional design, IMO. It's not small, but not much bigger than a dual 12" design would be and you'll spend significantly less on amp power. In a 10" version with legs, this would make a really attractive HT "column" sub that the significant other could put a knick knack on; I'm working with the wife to determine if this configuration or a TT is the best option for our living room. Sound-wise, I'd suspect the TT is the best choice, but SAF is high on the list of things I need to worry about.

[Wes Whitmore]

It's hard to keep people from retweaking a balanced system in the search for more volume, especially youngsters...they should allow you to disable to 2 band EQ and Loud button on head units after you turn the keys over to the owner...hopefully Junior will keep your settings!
Wes