Horns V. Vented Subwoofers
Everywhere I go I hear sound systems of dubious quality, I see people blowing woofers and drivers in large numbers and I see people working hard on audio jobs just to make enough to pay to keep their audio systems functioning rather than profiting from their labor and investment. This doesn’t have to be the case. I believe its possible to show people that buying a quality system package is ultimately not only less expensive but is, in fact, much more profitable than buying a pile of parts that sort of fit together.
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 essentially 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 portable horn-loaded bass cabinet that would reach a minimum frequency of 30Hz. I had to look for a more practical way to deliver the deep bass I wanted to incorporate into the horns.
Eventually I designed a hybrid box that incorporated a vented section with a horn-loaded section and it produced massively low bass but even with the horn-loaded section, it lacked the impact of the purely horn-loaded cabinets. The box was also quite large and complicated. It was impractical, from a size and cost point of view, to build a cabinet that would combine the vented and horn-loaded segments in one construction.
What I then did was begin to develop a vented box to see what I could achieve with a highly optimized vented box. What I got was a really magnificent, musical and ruler-flat subwoofer with massive deep-bass output capabilities and virtually unlimited power handling, but it still lacked the impact I loved about the horn-loaded boxes.
In order to deliver both impact and depth I started combining the two types of boxes and found it to be problematic to integrate the two types. I could get the super-deep bass I wanted from the vented boxes and I could get the massive impact from the horns but getting them to line up and do it together took a great deal of time, measurement and experimentation. I finally figured it out and it was magic! Massive shock impact with body and depth I’d never heard or been able to achieve through any horn subs alone, especially since they had to at least fit through a door.
Not only do I understand and agree with the love for the impact of horns, I have improved upon it, to make it even more impactful. Think of it this way, if an 80 kilogram man hit you in the chest with a solid punch, it would be a hard hit, but if that man was 160 kilograms, that hit would move you much further! Understand that to go an octave lower requires four times (4x) 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. This is effectively what I can do with the combination of the horns and vented boxes. The reason I do it with vented boxes is because to do it with horns would take up more than four times the space and that becomes impractical for both portability and for floor space in a nightclub.
Please understand that I am not suggesting using vented subs in the place of horn-loaded subs, I am suggesting using vented subs to extend and improve the impact of the horn-loaded subs.
Regarding the choice of amplifiers, I have heard opinions about all kinds of equipment, some of which are more extreme than others. I’ve even heard it said that if the signal is ever converted from analog into digital it is un-recoverably compromised. This just proves that one can take anything beyond the realm of practicality. I do my best to focus on the best practical solution.
The problem with anyone having an opinion about a piece of equipment is that in order for the opinion to be valid as anything more than an opinion, in other words for it to have value as a basis for making a decision, it must be derived from some form of test that eliminates any other variable from influencing the opinion. Personally I have conducted and participated in double-blind tests between amplifiers where all other parts involved in the test were the same. From these tests three things were evident:
1) Not everyone agrees on what “better” is.
2) There is very little difference between top-quality amplifiers and most people can’t tell one from another if they don’t know which one is playing. (People hear with their eyes.)
3) One amplifier may be better suited to a particular speaker than another.
The conclusion to be drawn is that the only way to choose the best amplifier for a particular system is to choose based on its compatibility and perceived superiority for use with the specific loudspeaker components of the system. In other words, you must somehow choose the loudspeaker system you intend to use and then audition every possible amplifier in order to be assured that there isn’t a better choice somewhere in the world. Naturally this is impractical unless it is your full-time job to know these things.
So, since most people form their opinions based on limited experience, and based on experiences with too many variables to isolate a causal relationship, it is highly impractical to make a decision based on a number of peoples’ unverified opinions. I can tell you my opinions, which are based on over 20 years experience in the industry and hundreds of system installations and productions, tests and experiments, but they will still be just my opinions, based on my personal preferences, and not necessarily perfectly aligned with yours. In audio there is virtually never an objective opinion. Everyone’s ears are different. Everyone’s preferences are different.
The last time I was involved in a double-blind comparison of amplifiers, the one that was consistently loudest on subs was Powersoft. Which one was loudest was measured and was therefore an objective conclusion.
You can drive yourself crazy trying to figure out the minutia of which components will be the best in every single position in the signal chain. You can also spend a great deal of money!
The third limitation is that 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 30Hz that would require the perimeter of the frontal area of the horn array to be 11.43m. That calculates to an array approximately 3m high by 3m wide or roughly 6 horn-loaded subs per side to deliver the performance my system design will achieve with just 3 subs per side.
The TRICK is combining the right horn with the right box in the right way. The vented box you choose MUST offer low frequency extension well below the horn and must be capable of output sufficient to match that of the horn. Horns are naturally more efficient than boxes, so they require less power. They convert more of the electrical energy into acoustical energy. Boxes are less efficient than horns, so in order to have a box (or boxes) able to match the output level of a horn an octave lower than the horn, that box must be able to handle a great deal of power. In essence, the trade-off between horns and boxes is size and complexity versus power demand. Vented boxes can invariably be built smaller and lighter than horns but they require more amplification to reach equivalent output. Further, boxes can’t deliver the impact of horns due to the limitation of coil/cone inertia. In most cases, the vented boxes can’t reach equivalency with horns before they reach either an excursion, thermal or distortion limit. The answer has been to add more vented boxes until there are enough drivers to match or beat a horn-loaded array. Unfortunately, all those vented boxes might be able to match the output LEVEL of a horn-loaded array but not the transient dynamic response and impact of the horn-loaded array.
From this information you can gather that in order to install a horn-only subwoofer system with flat frequency response to 30Hz would require a large amount of space, cabinets and money. BUT low frequency response is NOT what people love about horns. It’s the impact and immediacy of their delivery. It’s the tight and punchy-ness and the tremendously dynamic transient response. 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 and perfectly suited to delivering the impact that people love about them.
If you asked me to design you a system for the ultimate in sound quality, I might make different choice than if you asked me to design you a system for ultimate reliability or ultimate SPL or ultimate simplicity. Somewhere we must make choices and all choices involve compromises.
Horns have 3 factors that dictate their performance.
Their first limitation is the length of the horn. The internal path length between the driver and the mouth must be long enough to support one-quarter wavelength of the lowest frequency that horn (or array of horns) needs to reproduce. If the horn isn’t long enough the pressure wave will exit the mouth while the cone is still pushing forward and the “load” on the driver will fall off, losing efficiency and allowing the driver to hyperextend. Therefor, a horn must be long enough to support the expansion of the wave to the lowest frequency you need it to play. Assuming 30 Hz is your low frequency target, the horns you choose must be AT LEAST 2.85m long.
The second limitation is the flare constant. This is how quickly or slowly the area of the horn increases down the path length. Low frequency horns require a slow flare, making their construction more complicated when folded into reasonably-sized cabinets. When designing a horn with a low frequency flare rate one must choose on a continuum between efficiency and size. Most horns that are made in a reasonable size are NOT built with a low flare constant AND a long enough path. One, the other or both are compromised. This leads to peaky response and “horn honk” and a total lack of depth in their performance. These are compromises I’m not willing to live with.
While a single horn can’t achieve low frequency extension in a reasonable size due to the limitations of low frequency horn-loading, a single box can reproduce extremely low frequencies. Our SSP218 Subwoofer, with 6000W power handling can also reach output parity with a horn. Using 2 of the SSP218 Subwoofers allows for parity to be reached at half power, taking the strain off the system, lowering distortion and ensuring long service life. The combination allows the horn to deliver the impact they are known for and leaves the low frequencies to the slower cones for which they are better suited.
This solution takes advantage of both technologies’ strengths to create a system that offers the benefits of both with the weaknesses of neither. The combination overcomes the limitations of both the boxes and the horns. Provided the cabinets are properly aligned and integrated with each other, (which I do for you,) the shocking impact of the horn combines with the extended depth of the boxes while keeping the size and the power requirements reasonable and affordable.
If, however, you do insist on an all horn-loaded system, the B-Zero/D is the best single-box solution I’ve ever heard. The only thing you won’t have with 3 B-Zero/D per side is the super-low bass that nobody even knows is there until they hear it on a speaker like the SSP218 Subwoofer. (In my opinion, the combination is still better than either one alone!!)
Because I design boxes for a living I know the limitations of almost every loudspeaker design and configuration. The difficulty is in trying to explain the difference between competitor’s systems and what I can offer you. Are you comparing an assortment of speakers and amps to a complete, integrated system? Do they have the necessary time/phase alignment correction in the processing? Compared to any system I’ve ever heard, I can deliver deeper, louder, harder hitting, better sounding bass, and that is just the beginning. Its difficult to understand without the experience. The problem is explaining what “Oh My God!” feels like.
I know what bass is supposed to sound like. I know what bass is supposed to feel like. My subs were used on the main stage of the Ultra Music Festival year after year because nobody else could deliver what I can. We delivered 120dB flat to 30Hz at 120′ (front of house mix position) for 20,000+ people with only 16 SSP218s. In over 4 years in production, we have never lost a single voice coil in that box and we’ve had Bassnectar, Freq Nasty, Datsik, MSTRKRFT, Deadmaus, Black-Eyed Peas and so many others try to push our systems to the limit. They still haven’t found the limit.
What is “Oh My God!”? Its what happens when you hear a familiar song and realize there are layers in the music you’ve never heard before. Frequencies below the capability of what you’ve heard before, dynamics above it, textures behind it and subtleties within it. Its the experience of being immersed in the music, swimming in it, being a part of it. Its beyond hearing it. It turns the air into a liquid. Its the transcendence that happens when you fully integrate the senses of hearing and feeling into the experience of music and dancing. For those who get it, its an instant addiction. It takes your breath away, modulates your voice, caresses your skin, moves your clothes, blows you hair and gives you warm chills….
Such a system will allow you to listen at very high levels and not be in pain. It sounds big and effortless and open. From barely on to dangerously loud, it will be crystal clear at any level and will keep the same character no matter how high you turn it up. It offers tremendous loudness with no compromise in quality. Its intelligently designed so that you have enough headroom that you never force it to strain and distort and compromise the experience of the audience.
In what I am offering, there is no need for you to have to choose tight over deep or deep over tight or make any compromise. I know how to set up subwoofer systems better than anyone. I’ve been doing this continuously since I left the hi-fi business in 1987. My companies have done the sound for over 100 clubs and easily as many shows and festivals. You will have tight, controlled, kicking bass that goes lower than any song you are ever likely to play on it.