Does size matter?

Or consider keeping the Credos and upping your, as yet, unspecified electronics. (hint).

Chris

A question that requires a treatise to give a full answer! The following brief commentary is all assuming the same cabinet effects (i.e. keeping the detail solely to consideration of the drive unit). Also this is focussed on the difference for reproducing the same frequency range, in this case bass, not considering size of speaker and its effect on upper frequency response if not curtailed by a crossover.

1. For any given sound pressure in the room (volume), the same amount of air must be moved, so the larger area of the driver cone the less distance it has to move. (Unavoidable fact of physics)
2. Because the human ear is not linear in response, with a bass driver the lower the frequency, the greater the amount of air that must be moved for the same perceived sound level, so the more any size cone has to move.
3. For any speaker there is a limit for the distance that the cone can move, or rather a limit beyond which movement will not be linear (causing compression of the sound), and a physical limit beyond which the cone cannot move. This combines with 1 & 2 to mean that for the same construction technology a larger cone can reproduce lower bass at a given volume than a smaller cone.
4. Cones must be stiff to avoid distortions due to parts moving different amounts, or resonances within the cone. A larger cone is harder to keep stiff, so has to have more reinforcing which makes it heavier than a smaller cone by more than the ratio of their areas. A heavier cone has more inertia and so is slower to start and stop moving, with the result that the bass can be 'slower' than with a small cone.
5. A balance between the opposing limitations of cone movement and inertia effects (depth and power of bass vs speed of bass) can be achieved with multiple smaller cones covering the same music range at the bass end, and this approach is used by some manufacturers, with the added advantage of facilitating a narrower front baffle if desired, however there can be disadvantages including having a wider (or rather, in most cases, taller) source area and more complicated electrics.

Meanwhile, it is a fallacy that a larger speaker necessarily needs more power than a smaller one to create the same sound level as a smaller one: it all depends on the motor (magnet) design and suspension stiffness, just the size and weight of cone: for the same motor and suspension it would be true, but in reality bigger drivers tend to have bigger magenet assemblies, though some drive unit manufacturers have been known to use the same magnet assembly on more than one size of speaker. 

Domstic hifi speaker design is largely a matter of balancing not only the drive units, but the type of loading the cabinet places on it, the cabinet size (both of these factors can seriously affect the depth of bass it can reproduce), also shape and general appearance, plus in the case of passive designs the complexity and quality of the crossover, all against cost. 

Will99 posted:

I understand the comments above, but it has always confused me how earbud speakers or headphones can reproduce low bass notes with their relatively tiny drivers compared to normal loudspeakers. How does this work - is there a relationship between frequency and amplitude so that tiny drivers can still generate low frequencies but just at low volumes ?

Will, it's a question of how the speaker couples to the volume of air it's driving. Earbuds couple to a tiny column of air between the bud and your ear drum, easily causing movement of the cillia. Now consider the volume of a room and the size of the typical speaker. In relative terms the speaker is far smaller than an ear bud. The obvious example of this is when you take an average speaker in a typical room and get good bass, then put it in a large room and watch the bass vanish. The speaker simply can't couple to the larger space and move enough air to produce the soundwave that your ear picked up in the smaller room.

Hope this helps.

Frank.

My own speakers have 10 inch bass drivers, with a cone made rigid and light by being made of expanded polystyrene, end I wouldn't want less bass extension and power capability than that can achieve in its large transmission line cabinet. For dual drivers that would be roughly equivalent to dual 6.5 inch drivers to give the same piston area (provided they have the same throw characteristics). 

Will99 posted:

I understand the comments above, but it has always confused me how earbud speakers or headphones can reproduce low bass notes with their relatively tiny drivers compared to normal loudspeakers. How does this work - is there a relationship between frequency and amplitude so that tiny drivers can still generate low frequencies but just at low volumes ?

Exactly that, only a tiny volume of air needs to be moved around in the ear canal to achieve low frequency activation of the ear drum.  To achieve the same in a whole room requires a much larger volume of air to be shifted around.  This is also why the power requirement for headphones is so much lower than for speakers.

And it's why so many people unwittingly damage their hearing. The headphones go loud cleanly so there's little to no appreciation of just how loud the signal is!

Frank.

Yes. Says the DBL owner. 

Yes. Says the S800 Owner.

Best post for me in a long time. Great contributions. I have been wondering myself after moved from humble snell e3 (with 8' bass and tweeter) to kudos s20. Been missing some of the slam and scale in the low-end. Beyond that I really like the s20. This post confirms what to try to look for next as the OP

Now what are the great options out there excluding secondhand? Who offers the magic 8/1? I was never drawn to the speakers with many small cones..

Thanks Lars

Frank Abela posted:

And it's why so many people unwittingly damage their hearing. The headphones go loud cleanly so there's little to no appreciation of just how loud the signal is!

Frank.

Pardon?

Sorry, couldn't resist it.