Why is good, deep bass so difficult? - Myths and their Busters

+1 Audiokinesis and Erik

15" and larger woofers are key to good bass. You can’t beat the advantage of a large surface area except with multiple woofers. Multiple woofers are harder to drive so not a good choice. Basically....

One 15" woofer is equivalent to
Two 12" woofers
Three 9" woofers
Six 6" woofers

The amp controls the woofer and the air suspension suppresses the resonance of the woofer if properly designed. A woofer designed to work without a box may have a stiffer suspension but these are an exception rather than the norm.

erik

Placing weights on the top of a speaker may change the sound, for the better, I don't know, my speakers have sloped tops so I can test that out. I can tell you that you will not control cabinet resonance by adding weight. You might change the resonance point. Remember that light objects have higher resonance, more massive objects have much lower and much more difficult to control resonance. Simply take a wine glass and ping it with you finger nail. Now to stop the glass from ringing simply touch it with your finger. Two laws of physics come into play here. The first is that low mass objects will resonant at a high frequency. the second is that composite objects will more quickly do away with unwanted resonance. When you touch the wine glass with your finger you are essentially creating a composite of materials, your finger and the glass. Two disparate materials. 

So I conclude with this: Purchase speakers that are made from composite materials. Two do not always assume that those big heavy massive speakers will have better bass. 

The weights issue of course is very much speaker dependent. :) I’m certainly not saying it is THE solution to THE speaker problem. :)

This particular issue isn’t resonance within the speaker panels so much as force and leverage vs. the mass of the entire speaker being able to rock the entire assembly.  Of course, those of you with 200 lb speakers can ignore this issue.

The woofer motor exerts quite a bit of force that changes rapidly. This could in theory actually move the speaker, or tilt it, causing some self-cancellation akin to the Doppler effect.

Should you spend a lot of time and money on this particular issue? I don’t think so. I used to own Focal Profile 918. Rather tall, light weight speakers with woofers mounted relatively high. That is the type of speaker I think would benefit most.

Having force up high gives it more leverage, and more ability to rock the speaker back on it's rear feet. The Profile was easy to knock over even with after-market supports.

The theory is basic physics, but I haven't done any modelling in regards to "normal" woofer forces and speaker masses.  If you are worried, put a nice steel weight on top and listen. Then if you hear no difference at all send me a case of Casamigos tequila on top of which you have written the words "You were totally wrong."


Best,

E

It’s not really a mass issue for the tops of speakers. It’s placing something that acts like a diode and allows the otherwise trapped energy in the speaker cabinet to rapidly escape to the outside air via a path of least resistance.  This is why things like those Totem Beaks or cones, especially NASA grade ceramic DH Cones, very hard but not very massive, but massive enough, are often so effective placed on top of speakers. 🍦 There used to be a product Tekna Sonic that was purpose built for attaching to speaker cabinets that accomplished the same thing. For the same reason cones can often be placed on top of the electronics chassis or tube traps and accomplish the same sort of thing, dissipate energy rapidly from the system. Crystals also dissipate mechanical energy in similar circumstances.