Is There a Way to Lessen Vibration On Cables From Powered Speakers

@gaukus

Others may chime in because I am far from an expert. You can prevent/minimize vibration or drain vibration. Given your feedback on the second speaker behavior, you may need to do both.

You will achieve dampening/preventing with the putty and tightening all screws you can get to.

Do you have the speakers sitting on any type of stand or support? You may also consider when you get the putty to roll 4 balls of the putty and place underneath the speaker and the surface (be mindful of the surface since the putty could possibly make a spot on your surface it is happens to be a nice surface). Maybe a cutting board as a base might improve things some?

You can probably tell that I am trying to be careful with recommendations given I don't really know the vibration characteristics and whether they originate from your cabinets, your drivers being loose or backwaves from the drivers. I am also trying to recommend things that are on the cheap and arent a total loss if they dont achieve your goals ie: a cutting board, etc. Another potential solution would be to swing by a best buy or car stereo shop and see if they have a small sheet of dynamat. You could cut it up to place in several locations within the speaker cabinet to absorb some of the internal reflections/vibrations. Beware, this could kill the liveness of the speaker as I havent tried it with this speaker as well as I dont know if thats the source of the vibration.

It is actually a lot better to have the speaker on springs or even better Podiums. Either of those is way better than anything firm or rigid as anything that couples like that brings ringing, smearing, and harmonics that color timbre and tone altering natural instrumental character. 

@millercarbon

I wonder if there are different qualities to the use of rubber bands.  Whilst awaiting my bag of rubber bands, I had two wide rubber bands from a bunch of asparagus.  I tried using those and they not only didn't impact the vibrations, they took on no vibration. It didn't seem to matter what the tension or lack of tension was.  I began to consider that there maybe something in those bands that makes them food-safe and therefore not adapted to vibration absorption? The typical rubber bands are rather "squishy" and these food rubber bands are stiff and relatively unyielding.

I also was thinking about how Shunyata's "Dark Field" risers are designed. They seem to have something of a larger component with a stretch of rubber. It could be that the structure has internal filler or shock absorbing material?

These are not the bands you are looking for.

@gaukus

@millercarbon is right, those kinds of bands would be far from ideal.

Once again, its your experiment and your money but if you can't tweak your Audioengine speakers to vibrate less for very, very little money, you will be throwing good money after bad. After checking to see if they can be tightened properly in the right ways and appropriately damped in the right ways to avoid killing the liveness of the presentation then you will likely need to recognize that you are potentially exceeding the speaker's capabilities regarding vibration control at given volume levels.

Getting a speaker to scale is tough...and its tougher still when its a small box, built to a price point and houses all the amplification as well, which was also built to a pricepoint. The Audioengine speakers are really nice for the money...but spending hundreds of dollars on tweaks might initiate the law of diminishing returns quickly and could lead to the law of absolutely no returns kicking in.