Why use subwoofers?

[rwnano]

From reddit

"I've been a "no sub" guy for a long, long time. But learning on Reddit has helped me start to consider what a sub would add aside from frequency range extension. My epiphany was, it's not just the speaker; it's the amplifier built into it. Delegating the most energy-intensive frequencies to a separate amp that happens to be built into a specialized speaker housing--even if doesn't bring a net extension of frequency response to the system it joins--stands to free up all other amplification resources to stay poised and dynamic, and the speakers being driven aren't in motion with low frequencies while also trying to do more articulate work. If that was obvious, it wasn't obvious to me. Oh well."

 

[Phew]

 

[dafreaking]

Bro are you trolling?

 

[hifimaddy]

 

[Yelamanchili manohar]

 

[Yelamanchili manohar]

 

[rwnano]

just found that reddit comment interesting about why use subwoofers....shared with the board

 

[mbhangui]

From reddit

"I've been a "no sub" guy for a long, long time. But learning on Reddit has helped me start to consider what a sub would add aside from frequency range extension. My epiphany was, it's not just the speaker; it's the amplifier built into it. Delegating the most energy-intensive frequencies to a separate amp that happens to be built into a specialized speaker housing--even if doesn't bring a net extension of frequency response to the system it joins--stands to free up all other amplification resources to stay poised and dynamic, and the speakers being driven aren't in motion with low frequencies while also trying to do more articulate work. If that was obvious, it wasn't obvious to me. Oh well."

There is something known as natural frequency for any vibrating object. Larger the object lower is the natural frequency. At the natural frequency it requires the least amount of power to move the object.

Subwoofers have speakers cones of larger diameter than most floor standers. Bookshelves have even smaller sized speaker cones. Smaller the speaker you have to design the box very well with large dimensions to lower the natural frequency. Also the suspension has to be very very less rigid where the cone is stuck to the round metal frame of the speaker. So again the quality of the suspension has to be designed extremely well for smaller speakers to reproduce low frequencies. Hence it is less of an effort for subwoofers to produce lower frequencies than bookshelves and (even floorstanders).

Since the mass of the speaker cone increases with larger speakers, and also larger volume of air needs to be moved, the power requiried to produce lower frequency is more. Hence moving lower frequency reproduction out from bookshelves and floor standers, reduces the power required from the main amplifier, thereby improving the dynamic response of the main amp. So adding a subwoofer reduces the load on the main amps and make them perform better.

To understand this concept of natural frequency, visualize drums of varying sizes. Drums with larger diameter will produce lower frequencies than drums with smaller diameter. Same is the case with tuning forks which we used in school physics labs. Longer tuning forks produce lower frequencies than shorter tuning forks. In the end it is simple physics.

Same is the case with long suspension bridges. They have low natural frequency. So if soldiers march in unision, it can be enough to make the bridge swing up and down. Hence such bridges are crossed by soldiers marching out of steps over a makeshift suspension bridge built in a hurry during war or war mongering exercises.

EDIT: The opposite is also true. It will take humongous power to make a woofer vibrate at 10000 Hz. Hence for high frequency reproduction you use tweeters with small size. Dogs have larger vocal cords, birds have small vocal cords. Hence dogs cannot chirp or tweet and birds cannot bark.

 

[DB1989]

EDIT: The opposite is also true. It will take humongous power to make a woofer vibrate at 10000 Hz. Hence for high frequency reproduction you use tweeters with small size. Dogs have larger vocal cords, birds have small vocal cords. Hence dogs cannot chirp or tweet and birds cannot bark.

You just couldn't resist with the analogy, could you?

 

[Saiganesh]

Well with subs we can spend lesser on front stage speakers (and rears as well) and amps...as sub frequencies are not much directional - carrying those frequencies on all the channels adds upto the cost of speakers and amps.
also low frequencies from the same box tend to bleed into mids - drivers of the same box at higher volumes and tend to distort the mids...
So...