Reprinted with permission from Aperion Audio:
The subwoofer is essentially the most specialised speaker in your house theater, typically devoted to producing bass frequencies which might be round 100 Hz down to twenty Hz. As a result of subwoofers use giant drivers and are usually powered by their very own amps, they’ll produce the lengthy wavelengths of low frequencies at the next dB degree than a conventional loudspeaker. However there are just a few methods to design a subwoofer and every has its professionals and cons. On this article, we’ll undergo the various kinds of subwoofers with an emphasis on the advantages and trade-offs you may count on.
Ported Subwoofers
Ported subwoofers are pretty widespread as they provide a simple solution to serve up thunderous slabs of thick bass. In case you’re unfamiliar with speaker design, a port is merely a gap within the cupboard, often prolonged contained in the speaker by a tube however not at all times, which permits air to flee. Ported designs are additionally typically known as “bass reflex” audio system, as sound waves, specifically bass frequencies, are additionally pressured out of the port together with the air. Since a port is a method to beef up the bass coming from a speaker, it’s no shock that it’s a common design selection within the case of subwoofers.
Each port has what is known as a resonance frequency, which is the frequency at which it vibrates and is especially as a result of port’s size and width. It’s the sound waves on the resonance frequency, or those which might be near it, that might be boosted by the port. In case you have been to have a look at the frequency response graph of a ported subwoofer, you’d see that there’s a peak at this resonance frequency. The speaker engineer can select which frequencies to spice up by altering the size of the port, however the reality stays that solely a small vary of frequencies might be intensified by the port. Due to that, the perceived efficiency of the subwoofer can range relying in your supply materials. As an example, say you’ve a subwoofer that has a port with a resonance frequency of 25 Hz. That may make materials that comprises that the 25 Hz frequency sound wonderful, with resounding bass superbly filling your room. However in case you are listening to some rock music that doesn’t actually have something under 40 Hz, you lose all the advantages of that port and will marvel in case your subwoofer is even powered on. One other potential disadvantage to a ported sub is port noise. As a result of all of that air is being pressured out of the port, typically the air turbulence could cause a “chuffing” sound because it exits the cupboard. That is usually not a problem with properly designed ports, however it will probably nonetheless occur at larger volumes.
Sealed Cupboard Subwoofers
In contrast, a sealed cupboard subwoofer doesn’t use a port, the one place for sound to depart the cupboard is from the energetic driver(s). The benefit is that you simply get a pleasant even response from the sub throughout all frequencies with none large peaks, so long as it’s a properly designed sub. Sealed cupboard audio system are typically referred to as “acoustic suspension” designs. Along with getting a extra even sound from a sealed cupboard speaker, you don’t have to fret about port noise and the general sound of the sub must be extra tight and outlined compared with the extra boomy sound you get from a ported subwoofer. Nevertheless, the improved sound high quality comes on the worth of sound amount and in some instances depth. That’s, a sealed cupboard might play quieter and will not be capable of hit frequencies as little as a ported sub. A few methods to assist compensate for which might be a bigger woofer and extra highly effective amp, however the first will end in a bigger field. Provided that one other benefit of sealed subs is that with out a port they are often constructed smaller, sealed subs don’t often go the route of bigger woofers. Sealed cupboard subs are used pretty typically in automotive audio as a result of filling the small house of a car with bass is much simpler than a big room. However for dwelling audio use they’re rather less widespread and will not present the identical quantity of total output and deep bass as a ported design.
Passive Radiator Subwoofers
Right here at Aperion Audio, we take a 3rd strategy which in some respects splits the distinction between ported and sealed cupboard subwoofers and might provide the perfect of each worlds. All of our Bravus II subs use what’s referred to as a passive radiator design. So as a substitute of a port, they’ve two drivers along with the energetic driver. However these further drivers, or passive radiators, should not wired to the sub’s amp.
Since they aren’t powered by the amp, they solely transfer forwards and backwards because the air inside the cupboard expands and pressurizes. The passive radiators permit sound to flee from the cupboard as a port does, however with an essential distinction, because the radiators do not need a resonance frequency like a port, they permit a wider vary of frequencies to be emitted. As talked about, this units up a better of each worlds state of affairs, the sub produces the good flat frequency response of a sealed cupboard, but in addition permits for the upper degree of output of a ported design. One other benefit is that as a result of there isn’t any must have room for the port contained in the field, we will preserve the general dimension of the subwoofer to a minimal. The small footprint mixed with the large sound of our subs is a frequent, pun meant, praise we get from our clients. Lastly, we don’t have to fret about port noise and a passive radiator sub offers an exceptionally musical and clean bass sound. So having gone by each design possibility prior to now, ported with our Intimus S-8, S-10 and S-12, passive radiator with the S8-APR and even a twin driver sealed cupboard with the Bravus I, we really feel that the passive radiator possibility affords essentially the most optimum design that gives nice sound with out having to compromise on total output. Having stated that, we encourage you to audition and hearken to as many subs as you may when you find yourself procuring round to seek out what works finest for you in your arrange.
In case you are on the hunt for a brand new sub, a very powerful issues to remember are your room dimension, that’s to purchase a sub that may fill your house, and to additionally buy one which provides you with the sound high quality that you simply desire. We hope this take a look at subwoofer designs has deepened, pun additionally meant, your understanding of how they operate and the advantages of every. As at all times, we want you cheerful listening!
