Hi All,
Hayden is right.
"Fast Bass" is a noexistant fairytale used by the non technically inclined and manufacturers to fool themselves and others.
For anyone interested in advancing their understanding of the technical side of audio.
Pressure from a subwoofer is proportional to the product of accelleration and surface area.
Therefore all subwoofers of the same size must have exactly the same accelleration if they are to produce the same output.
If one had higher accelleration it would be louder and you would have to reduce the volume level until it's accelleration was the same so the output level would be matched with the mains.
Subwoofers with larger cones must have less accelleration to produce the same sound as smaller subwoofers.
A 15" subwoofer that is operating at the same accelleration as an 8" subwoofer will simply be as loud as four of the 8" subwoofers operating at the same accelleration.
Once you limit the bandwidth for a subwoofer to below 100hz nothing can happen quickly it is a mathematical fact shown by Fourrier long before subwoofers existed.
Resolution in the frequency and time domains is connected the more you restrict the bandwidth in the frequency domain the less resolution can exist in the time domain.
The implications of this are that even an 18" subwoofer with a moving mass near a pound if properly designed can give flawless performance.
When I refer to fast bass I'm speaking of acceleration and recovery times of the woofer(s) not the frequency being reproduced. Woofers have very substantial mass relative to that of tweeters. Even though the reproduced frequency is almost slow enough to count, you still need a design that can stop, start and change directions instantly. A slow moving woofer sounds sluggish, sloppy and ill-defined.
As described above accelleration is just the pressure being produced by the driver.
Heavier cones are simply driven with more force to achieve the same result.
Recovery time (or settledown time) is indicated by freqeuncy/phase transfer function (which many people don't know is exactly the same thing as impulse response just another way of looking at it).
The smoother and more extended frequency/phase response is the faster a driver will settle after an impulse.
Poorly defined bass is usually indicitave of distortion.
Uneven frequency response can also cause poor bass though subwoofers with narrow peaky response curves are often described as sounding very "fast" when in fact they are the opposite.
They are light and fast paper cone drivers with a surround that is similar in appearance to the B200s ("acordian style").... as opposed to so many subs out there today with those thick rubber surrounds that need big watts to move them
Hi Vinnie,
Accordian surrounds have one application only.
They are the least resonant of all types of surrounds (and durable and cheap) which makes them suitable only for midbass/midrange drivers especially pro drivers where practicality is emphasised over quality.
Subwoofers cannot take advantage of accordian surrounds freedom from resonance because they are not used at frequencies where surrounds will resonate.
For subwoofers an accordian surround is to restrictive and their excursion capability too limited.
Foam surrounds are the best for subwoofers as far as sound quality goes due to high compliance and linearity.
rubber surrounds are tougher and better looking but suffer somewhat in terms of hysteresis and creep.
Those ZuAudio speakers look awesome and I'm glad you guy's like em but I would caution you that they are not throwing straight dice.
The response chart they are showing for their top of the line MTM is not real which means they have no idea what their speakers are really doing.
If they properly designed their speakers it would have been easy for them to include charts from their design system on the website.
The plate amps on the back of their subwoofers are the ultra cheap imports you can buy for under $100.
The prices they are charging are outragous.
Daryl
