Polk Audio LSi9 Fortress Level

Parts List -

Tweeter Network -
Clarity Cap ESA
Mundorf Mox Resistors

Midbass Network -
Clarity Cap PX
Bennic Electrolytic bypassed by Clarity Cap ESA
Mundorf Mox Resistors

Other Features -
Point to point wiring, New Monastery grade wiring techniques
Gold Plated, Insulated Binding Post
T66 Aluminum Terminal Plates, hand made in the USA
Delrin Substrate

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Hear the difference -


Learn more about Fortress Mods, Click Here!

Want to Do It Yourself? No problem!

Thoughts from the customer?

"The Fedex guy pulled up this morning holding a box that looked like what i have been eagerly anticipating; My LSi 9's are back from Trey in NC.
I carefully unpacked the box noting that Trey took great care to make sure that short of a nuclear attack, that my speakers were well protected. We all know that shipping speakers is a risky proposition, and we all saw what that delivery guy did with that flat screen tv when the gate was locked.
I carefully inspected them and gave the lacquer a little buff up, and took the 7's off the stands and connected them up. The new binding plate and posts have a very clean look, and mechanically the posts are perfect.
So I got me a fresh cup of joe, and decided to give them a listen.
Anybody who owns or has listened to the LSi 9 knows they represent one of the best bang for the buck audio values in recent history. The fine folks at Polk definitely made big sound come out of a relatively small box.
The VR3 changes are very noticeable.
While the bass was always very good on the stock 9, now it is very concise, quick, and I notice that after the initaial attack of the bass note, that the sustain of the note is very warm and smooth, a detail that i did not notice before. Bass players use hi wattage amps with 15" speakers to get that sound, and although I recognize there is no way these little guys can possible move that much air, the reproduction is accurate and very pleasing.
As a guitarist, I am very tuned to tonality, and relate to how guitars and other stringed instruments are portrayed by a speaker.
While my 9's were away, I was listening to my Moni 5's and was very impressed by the mid qualities they were able reproduce. I am happy to report that I can now sell my 5 and the modded 9's now exceed the 5's ability to make guitars sound the way I like to hear them. When someone is playing clean i hear that open back crunchy sound that I crave. I listened to John Petrucci/Dream Theater's On the Backs of angels.. There is a 12 string intro, that goes into a creamy sort of melodic passage that is followed by triple rectifier Mesa Boogie sound which all sounded dead on.
I as trying to think of an acoustic guitar song to test, and played Black Water by the Doobie Brothers and was please that I was able to hear all the detail that a guitarist would hear accurately... picks strumming stings, and those realistic little buzzes and twangs that are really there that some how get lost in the mix.. The fiddle piece was sweet and I could hear the bow on the strings. The vocals and harmonies were tight, and not compressed; I distinctly could pick out the 3 and 4 part vocals without effort.
As I try to evaluate the crossovers handling of the ring radiator tweeters performance, I think the stock 9's used the rr tweeter as more of a marketing gimmick, and although it performed well, and never sounded the least bit harsh to me, this mod seems to handle the handoff between the mid and hi without me noticing it to be as pronounced as it was pre mod, and now smoother and more accurate... cymbals are ringing like real cymbals, and I don't hear any evidence of over accentuation. The piano on Steely Dan's Aja was near perfect, and I was equally impressed at the Saxophone and Drum passages as they pegged my amps VU meters.
Overall the LSi 9 is a fine loudspeaker, and the VR3 mod makes it a great speaker. If you have a set of 9's and the power to drive them this mod makes them sound incredible across the musical spectrum that I have tested so far.
I will post more impressions, and consider the VR3 Fortress mod a very worthwhile bang for the buck enhancement.
Thanks Trey!" - Mike (LSi9 Fortress)

"Just wanted to take a second to give some props to Trey for the great work he does with his speaker mods. I got a pair of LSi9s modded and a LSiC.Not only did I get consistent updates (often with really cool pictures of the components), Trey works as hard as he can get the orders turned around fast and shipped insanely well packaged and safe. All for an extremely reasonable price. I've got a small audiophile-vocabulary, but I'm super satisfied and happy with my purchase. I've been able to consul consolidate my speaker setup since I'm happy with the modded LSi9s ability to pull music / movie double duty. anyway, if anyone is considering using Trey and VR3mods. Stop it, and order! :-) Thanks Trey!"

"I plan on doing a short write up. But in short; excellent!! The improvement in sound quality took the speakers to a level that I really didn’t think was possible; especially on my modest system. Just about the best money ever spent. Thank you" – Chris

"So I've been messing around with placement now that I've moved some other speakers out of the room and this LSi's sound incredible.  Just wanted to say thanks again.  Great clarity, the bass is there now that I have them spaced from the walls correctly and the air between the instruments is great." - Jason

"After a few months and several hundred hours later It's now a huge grin.  The clarity in the midrange and the detail in the highs is amazing.  It also takes less power to get to my sweet spot in listening and the speakers can handle more power before they start to break-up." - Michael

"Thanks for checking up on my speakers! I love them! The upgrade is worth every penny IMHO. Somehow the imagery had gotten better. My wife and I have been fooled many times by a sound we swear was coming from a source behind us or off to the side." - Richard

"The timbre of the speakers completely changed and there's a lot more clarity across the board, particularly in the highs. There are times, when I've felt they actually sounded somewhat bright.....in a good way (not the knives stabbing your ear kind of way).
    I know this is a cliche'd phrase, but it literally sounds like someone pulled a blanket off of my old LSi's and revealed what they 'really' should sound like. Soundstage is much more open, and the sweet spot (where these speakers just grab your ears) is much wider.
    Bass seems tighter, more accurate and has significantly better timing, but I'm not experiencing the increase in the amount/volume of the bass that others that have modded their xovers have experienced, then again I'm in a huge, bass sucking room that even my VTF-3 has trouble filling." - Marco

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