The Quest for the Ultimate Subwoofer
During all my years in the business, I have been on a quest for the ultimate subwoofer. Horn-loaded subs were my preference and I started BASSBOSS originally based on the performance of the B-One and B-Zero horns. We developed a lot of horns over the years, and continue to do so, because horns have a number of desirable and beneficial properties compared to vented boxes.
There was, however, just one thing I was always missing from the horn-loaded subs: Really DEEP bass!
Other than building individual horns that are absolutely massive, or building a segmented horn comprised of many separate elements that combine to make one massive horn, there was not a practical way to build a subwoofer horn that was portable and would reach a minimum frequency of 30 Hz.
The Hybrid Experiment
Eventually I designed a hybrid box that incorporated a vented section with a long, partially folded horn-loaded section. It was 45 inches square and 24 inches tall. Although the box was also quite large, heavy and complicated to build, it was smaller and lighter than the B-Zero — and it produced massively low bass.
What I then did was begin to develop a vented box to see what I could achieve with a highly optimized design. What I got was a really magnificent, musical and ruler-flat subwoofer with massive deep-bass output capabilities and virtually unlimited power handling. As good as it was, it still lacked the impact I loved about the horn-loaded boxes.
Why Deeper Bass Hits Harder
Think of it this way: if a 160 lb man hit you in the chest with a solid punch, it would be a hard hit. But if that man was 320 lbs, that hit would move you much farther.
To go an octave lower requires four times the power and displaces four times the air for the same sound pressure level. If you can extend the power behind that initial hit by an octave, then it effectively hits four times harder — because it literally is four times the mass of air behind the hit.
The Three Physical Limits of Horn-Loaded Subwoofers
1. Horn Length Determines Low-Frequency Reach
The horn's low frequency limit is determined by how long it is. For a horn to be effective at 30 Hz, it needs to be 112.5 inches — that's 9.4 feet (2.86 m) long.
2. Flare Constant Controls Efficiency and Size
The flare constant is the rate at which the area of the horn increases relative to the distance from the throat. Most horns that are made in a reasonable size are NOT built with a low flare constant and a long enough path — leading to peaky response and a total lack of depth in their performance.
3. Radiating Area Sets the Low-Frequency Floor
A horn (or array of horns) must have a radiating area whose perimeter is at least one full wavelength of the lowest frequency to be reproduced. For 30 Hz, that requires the perimeter to be 37.5 feet — an array just over 6 feet high and 6 feet wide.
What People Actually Love About Horns
Low frequency response is NOT what people love about horns. It's the impact and immediacy of their delivery. Therefore, if you use the horns for that function and use direct radiators for the extended low frequency response, you can use smaller horns that are specifically designed for and perfectly suited to delivering the impact that people love about them.
Where We Are Today
The VS21-MK3 takes the hybrid concept and puts it in one box: V for Vented, S for Short-horn, 21 inch woofer. Deep-bass extension with horn-loaded impact, in a single portable enclosure. It's the logical conclusion of everything described in this article.
You don't have to choose between deep and punchy. You never did. You just needed someone obsessed enough to solve the problem.
