TADs SS Hibachi Amps

Audiobb,

I am using the terms to describe:

Overdamped = tight, well defined bass response that may be reduced in level relative to the mid band and beyond. This is often (though not always) characteristic of sealed (particularly acoustic suspension) systems, and less often (though ocassionally) seen in ported speaker systems.

Underdamped = looser, fuller bass that may be elevated in level. This is more often (though not exclusively) found in ported or passive radiator systems and sometimes in infinte baffle sealed systems where the cabinet volume is large relative to certain performance parameters of the woofer.

Technically the terms have a somewhat more precise meaning, but for the purposes of understanding my earlier post, I hope that this is useful shorthand.

Good Luck,

Marty

Marty,

Is correct. In fact the way the speaker mechanical and air suspension is designed is very important as to how it will sound. (actually far far more important than amplifier damping!!)

Here is a third term: "critically damped". This has been generally accepted as the best sounding most practical approach. This is neither overdamped or underdamped - it means that when power is removed then the speaker goes to the rest position faster than any other design WITHOUT additional oscillations.

Here is a link to Damping. The red curve is overdamped (like a screen door closing - uncommon in speakers - needs lots of force to make it move). The Blue curve is underdamped (quite common in speakers with a bass boost/hump). The Green curve is the "goldilocks" curve - critically damped or "just right" (often regarded as the optimum setup for a woofer)

You may ask - Why then do speaker designers use anything else except "critical damping"? Basically it boils down to tweaking to get more output efficiency or more bass extension from small boxes - for example an underdamped driver with a port can get you more bass (higher efficiency) but the bass may sound muddy or warm (and won't be very smooth in freq response). Conversely, a critically damped sealed box design will sound tight and punchy in comparison but won't have anywhere near the bass extension and efficiency. An overdamped design will sound very tight but will be extremely inefficient - needs lots of power - high power Class D SS amps and Active designs may make this a more viable option in future.

The above may explain why some ported small subwoofers with high bass efficiency may sound impressive but muddy or non-musical.

Thanks to both of you,Marty and Shadorne.These are both very good explanations.I now understand what this means.My speakers have very impressive and efficient bass output.However,in order to see in what category they fit (over or under or just right),i first need to acoustically treat the room.There are just too many reflections.
My speakers are Silverline Sinfonia (18Hz-28kHz,96 dB).They have two 12" woofers and one 7" mid-woofer.Each 12" woofer is ported.I don't think these are "overdamped".I think they come closer to "underdamped" or "just right".
This is next for now,amps will come after that.

Each 12" woofer is ported

If you see a small box speaker with small woofers and ports then generally you can guess that it is for bass extension (often underdamped).

If you see a very large box speaker with large woofer and large ports then it can be either bass extension (often underdamped) or for simple efficiency (may still be critically damped). In the case of very large box speakers the ports allow the designer to use a driver with an even more massive motor and magnet ( an electrically overdamped woofer, Qes) and place this in a ported enclosure to raise its Q or damping to be critically damped. (This is the typical design of what you see in studios with giant woofers and large 4 inch ports in very large cabinets - they are usually trying to get louder with a bigger motor woofer rather than deeper bass)