...In chatting with Ian during the development of the EP800, the main reason he mentioned in using a sealed box was because if it were ported with the super low frequencies involved, it would be impossible to control port "chuffing" and noise.
So he went the sealed box route. In doing so, sensitivity is lost because you're essentially throwing away all the back-wave energy, so to get the sensitivity back up, he used two big drivers with dual voice-coils on each, wired in parallel. By doing that, he was able to extract the maximum amount of power from the amplifier because the impedance of the two drivers' dual voice coils was around 1 ohm. So we didn't lose out in sensitivity.
Regards,
Alan
Ahhh, so he was able to squeeze out the whole 1 watt eh?
J/K
Excellent information Alan, exactly what I was looking for. You have indeed cleared up many unanswered questions for me personally with that explanation, I thank you for that. And in fact the reasons you give actually give my old beliefs in subwoofer box design differences credibility. If you go back and read the beliefs I 'used to hold', I said we car audio junkies prefered ported box's because they ultimately put out more bass. I didn't know why, but with your definition it seems this is because they are more sensitive. With less power we were able to achieve greater amounts of air moved as we made use of the 'back wave energy'.
But just as Ian explained to you, along with lower bass notes, we got a lot of port noise that interfered with the music. Which is why sealed subs were considered 'clean' and or 'tight', because there was no port noise to contend with.
Anyone that wasn't into car audio won't understand any of this. You see at least back in the 80 and early 90's you couldn't find 'all-in-one' car audio subwoofers. You bought a woofer (usually a JL Audio or Kicker), an amp (most people bought amps that made 500 to 1000 watts), and then you either bought (or made) a sealed box or a ported box to put it in. We certainly weren't engineer's, we were just kids who liked to give our back seat passengers back massages while cruising the strip. And with the three ingredients listed above, those of us who liked 'clean' bass used a sealed box. Those of us who wanted the most bass you could possibly create used a ported box. It was as simple as that.
And I'm assuming a lot of people who come on here who say they prefer the 'clean' sound of a sealed box is from that very same school of audio education that I came from. Given a generic driver and a generic power supply you're going to get more bass out of a ported box, and a cleaner sound from a sealed box.
Since those days hundreds of subwoofer companies have refined subwoofer box's remarkably. They now include a built in amp, and drivers that are either very sensitive or not so sensitive to accomodate the box design being used. This is why so many people on here tell those people who come on here exclaiming they prefer one design over the other, "there is no difference". Because with today's subwoofers there isn't.
But perhaps, just perhaps this information can help bridge the two schools of thought so that they can understand where each is coming from. Thank you for chimming in on the subject Alan!
