Self-powered speaker vs. vibration isolation

[coot]

The title says it all.

Many 'philes - myself included - go to great lengths to eliminate vibrations in our systems as much as possible. It seems to me putting the amp itself inside the speaker - itself king of vibration sources - defies all logic, yet some self-powered speakers are highly regarded for sq. How do they "get away" with it?

[firedog]

Lots of different ways. They can build separate boxes inside the speakers with isolation, they can use opposing cones so that the vibrations cancel each other out , etc.

[Jud]

21 minutes ago, firedog said:

Lots of different ways. They can build separate boxes inside the speakers with isolation, they can use opposing cones so that the vibrations cancel each other out , etc.

 

I wonder how/if the big magnets in the bass drivers affected the electronics in the amps.  Guess they have to do something to EM-isolate.

[wgb113]

Maybe they don't get away with it.  Maybe it's one of those things some audiophiles over-obsess over.  Maybe other things matter significantly more to what ultimately makes it to your ears?

[esldude]

If there is some negative to that vibration it is more than made up for by the positives of actively powered speakers.

 

The little JBL LSR305s I have above 300 hz mostly measure below .3 % distortion using REW playing at 95 db.  The reason they test higher below 300 hz is mostly due to pollution of the measurement by low frequency noise which is difficult to block out.   Plenty of non-powered speakers measure more distortion than that.

 

Could the LSR305s be better if done differently?  I doubt it.  They have a single chip that has an ADC, does a digital xover (and I think some minor DSP for FR of the drivers) then DAC to feed two class D amplifiers which are also part of the same chip. It sits right inside next to the woofer.  I have read of at least two DIY posts where people damped the inside and in one case damped that board holding the chip.  Making pretty much no difference. Maybe like wgb113 says it is one of those things of marginal value that is over-obsessed about by audiophiles.

[semente]

On 24/03/2017 at 6:09 PM, firedog said:

Lots of different ways. They can build separate boxes inside the speakers with isolation, they can use opposing cones so that the vibrations cancel each other out , etc.

 

Would this solve problems due to sound-induced vibration?