I have the LessLoss Firewire 640x connected to my LessLoss Echos End Dac, Innuos Zenith MKIII and SPL Phonitor and they are very effective. 

Contact Constantine at Atelier 13 Audio as he has a Home Audition Program. Try before you buy! 

 LessLoss Firewall for Speakers | Atelier 13 Audio (atelier13-usa.com)

I have used the LessLoss Firewalls for Speakers and they provided audible improvements. Neal

I find these responses to the Less Loss Speaker Firewall less than enthusiastic and certainly not convincing.

This product is not cheap. about $1600.00 per set, and most people will probably require two sets.

Putting a simple capacitor across your speaker terminals will yield immediate and vivid results. That's why in the future I may give the Stein version a try, they also make an inline version too. However I doubt the efficacy of inline.

https://www.steinmusicstore.com/collections/zubehor-speaker-match

I owned them for a time, but I ended up sending them back for a refund. I thought they closed in the soundstage somewhat, and they did not do anything positive with my speakers / cables.

But everyone's systems and taste are different.

ozzy

Not sure what @lordmelton is referencing. The reviews I have seen are all positive. Including the couple here.

Whatever, I have a set coming to demo and will find out for myself. The Stirn Music CAP seems a bit ever priced for the presentation. I could buy a CAP and put connectors on it for a hell of a lot less money. Maybe I will go that route.

How many sets do you need?

1 set is for 2 speakers.

I find these responses to the Less Loss Speaker Firewall less than enthusiastic and certainly not convincing.

This product is not cheap. about $1600.00 per set, and most people will probably require two sets.

LessLoss Firewall for Speakers | Atelier 13 Audio (atelier13-usa.com)