Vibrating speakers

All box speakers vibrate. No way around it. ’Ye cannae change the laws of physics Jim.’


So what to do?

Well, with existing speakers, if you really feel there’s an audible problem - there might not be if the designer has factored in cabinet vibration/ output into the desired sonic signature they wanted - you can try to stand them on something which might attenuate some of their cabinet vibrations. Sorbothane, springs or footers etc. Townshend Audio have a long history of looking at isolation but they are not the only ones. In my experience these products can help where the sound can tend to get slightly ’muddy’ with certain recordings.

With cabinet design there are usually two approaches. Make it either extremely rigid to try to force these resonances up the frequency range (hopefully out of the listening range) or alternatively make the cabinet lossy (BBC style) so they disappear beneath the bass floor where our ears are the least sensitive.

Or alternatively you can opt for planar types and open baffles where the box resonances are naturally less of a problem.

There is a third approach, quite rare nowadays, akin to transmission lines, is to try to carefully use the unavoidable resonances (why fight the impossible?) in the same way as musical instruments do, ie to actually enhance the sound.

I think Russell K loudspeakers employ this strategy and they certainly have their fans. The piano firm Bosendorfer used a similar approach for their loudspeakers, but I don’t know if they still do. In any case I would always prefer a speaker with slightly too much life, and maybe not measure absolutely ruler flat than one that does but has too little life.

None of the current solutions are perfect but hey it’s only 2020 and we still await the next major engineering breakthrough.

It could be closer than we think if AI keeps evolving at its predicted rate.

tatyana69

Good questions. I’ll try and answer as good as I am able - others may do better.


Q1 Why have a cabinet ?

Well without a cabinet it is difficult to get good bass. If you take a driver out of its box and play music you will notice the sound becoming weaker and very little bass. This is why subwoofers still come in boxes. You can get more bass by using larger drivers but most people wouldn't want to or be able to accommodate them.

Planars are an entirely different type of loudspeaker which uses a frame - not a box to reproduce sound.  

Open baffles also use a frame/ baffle but with conventional drivers and still no box.


Q2 Driver interference

Yes drivers can interfere with each but good designs try to minimise this by either using stiff baffles to mount the drivers and/or mounting the drivers carefully.


Q3 Why not 3/4 boxes?

You can have 3/4 boxes but they will cost more and remember that more drivers can also mean a more complex crossover. Not always desirable as even a 2 driver speaker can be already quite complicated. Some of the most expensive speakers multi driver/multi box speakers such as made by Wilson and Focal are built like this.

Q4 A concrete floor and a wooden floor?

A concrete floor is liable to have a different vibration than a wooden one in terms of resonances.

I’m guessing most speakers will perform better on a concrete floor, but there’s also the issue of secondary reflections. You know how voices sound different indoors and out - it’s a bit like that with floors and rooms.

For your interest I can also suggest that you watch this YouTube lecture by Dr Floyd Toole.

https://youtu.be/zrpUDuUtxPM

A fellow member djones51 posted the link recently and although the lecture is quite long it’s also very informative.

After a lifetime in audio Dr Toole has probably forgotten more about loudspeakers than most of us will ever learn.