JL C5 components on sound wall sound a bit muddy at loud volume.

[Steveopevo 10+ year member]

Will an amp stiffen them up? Perhaps I could cross them over at a higher frequency if needed.

Click to read more...

 

[trumpet 5,000+ posts]

Muddy sound is a problem that can be measured and most likely corrected. In a car the response will be very different. Adding more power might help reduce distortion, but we have no idea what was powering those speakers you heard or the quality of the music you listened to. This really ought to be a question for the shop personnel to answer.