Klipsch THX Ultra2 Home Theater Loudspeaker System Review

5.17.06 

Klipsch THX Ultra2 

Home Theater 

Loudspeaker System 

First Impressions 

The Ultra2 arrived as a pretty impressive 

pile of boxes, comprising 10 shipping cartons. 

Packed inside the cartons were three KL-650- 

THX (LCR), two KL-525-THX, (back surrounds) 

two KS-525-THX (side surround) speakers, two 

KW-120-THX subwoofers and one KA-1000 

power amp. 

Review 

Review by Mark Sanfilipo of Audioholics.com 

Figure 2: 

KL-525 

back surround 

and 

KS-525 side 

surround, 

grille covers 

off 

Company History 

For nearly six decades Klipsch Audio 

Technologies has held an enviably successful 

position in the American consumer audio 

industry. That sort of longevity (given the 

competitive, volatile nature of the speaker 

biz) is, in and of itself, a tremendous and 

rare accomplishment. That their success 

has come about with a product line focused 

on horn-loaded loudspeaker systems for 

both the pro and home audio use makes 

this achievement even more impressive. 

And Klipsch knows horns; some of the best 

& brightest loudspeaker engineers, both 

past & present 

have contributed 

their talents to the 

Klipsch product 

lines over the 

years. And it all 

began with one 

person, with 

an idea, and a 

rented tin shed in 

Hope, Arkansas. 

Figure 3: 

KW-120 

subwoofer 

and KA-1000 

2-channel 

subwoofer 

amplifier 

Figure 1: 

KL-650 THX 

without 

and with 

grill cover 

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Each item was shipped housed in its own 

carton, well-braced internally with Styrofoam 

and wrapped in a protective cover. In Figures 

5a - e we see the unpack sequence for one of 

the KW-120 subwoofers, illustrating Klipsch’s 

approach to product packaging. 

Figures 5a - e: 

Klipsch KW-120 Product Pack 

Note top & 

bottom Styrofoam 

inserts stabilizing 

the KW-120 

within the carton, 

c a r d b o a r d 

edge bracing, 

the essential 

plastic & foam 

wrap around the 

unit itself and the inclusion of the Speakon 

connector-tipped speaker cable. (More on the 

included cable later). 

Once out of their cartons you’re no doubt 

going to be impressed by the appearance of 

these loudspeakers. With or without grille cloth 

they look great! Industrial art would be an apt 

description. Surprised to read of a plain box 

cabinet being referred to as “art”? It’s the finish 

that makes all the difference in this case. The 

appearance of the Galaxy Black finish featured 

in the Klipsch THX Ultra2 system cannot be 

captured in a photo that does justice to its 

striking beauty. Both aesthetically pleasing and 

functional, the choice of this particular finish with 

this system was brilliant. How so? 

Aesthetically speaking, the Galaxy Black 

finish has a subtle way of lessening the visual 

impact of having 9 speakers clustered together 

in a home theatre. The finish is somewhat 

lighter than straight piano or charcoal black, not 

uncommon colors in the world of loudspeakers. 

Less stark than either piano or charcoal black, 

the finish is nevertheless dark enough to ensure 

the speakers present minimal visual distraction. 

Inside Look 

For the inside look we’ll use one of the KW- 

120 subs as the specimen of interest. 

Peeling off the grill cloth, the sub appears 

pretty much as seen in Figure 3 above. The 

four studs to which the grill cloth is attached 

are actually the heads of the 4 bolts holding the 

aluminum fascia in place. Removing the fascia 

we can then remove the driver. 

I laid the KW-120 on its back and proceeded 

to remove the bolts securing the driver in place. 

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Klipsch THX Ultra2 Home 

Theater Loudspeaker System 

Review Date 5.17.06 

Review Summary 

Manufacturer: Klipsch Audio Technologies 

Overall Rating: 4.75/5 Stars 

Value Rating: 5/5 Stars 

MSRP: $10,750.00 

7.1 System with 2Ch. Subwoofer Amp 

Pros 

• Tonally neutral 

• THX Ultra2 certified 

• High efficiency 

• Dynamic sound 

• Authentic detail resolution 

• Excellent placement flexibility 

Cons 

• Boxy-shaped cabinets 

• Protruding binding posts on the 

KS-525 requires relief cutout to 

accommodate flush mounting 

Once I had removed them all, I found the driver 

at first wouldn’t budge. It seemed like the thing 

was stuck in place. As it turns out, it wasn’t 

stuck at all. In actuality I had encountered 

a driver that was far, far heavier than I had 

anticipated. I haven’t weighed the driver and 

cabinet separately, but it wouldn’t surprise me 

at all if the driver turned out to weigh more than 

the substantial cabinet into which it is normally 

bolted. 

Figure 7a – b: 

KW-120 Subwoofer Driver

Specifications 

review 

KL-650-THX LCR Speaker 

Sensitivity (2.83 V/1m, averaged, from 300 to 3000 Hz): 97.0 dB spl 

Rated Impedance: 8 Ω 

Frequency Response (-3 dB): 48 Hz to 20 kHz ±3 dB 

Bass Principle: Bass reflex; front-firing port 

HF Driver: 

(1) 2.5cm (1”) titanium dome compression 

driver. Magnetically shielded. Coupled with 

rectangular 90º x 60º Tractrix horn 

LF Driver: 

2) 16.5cm (6.5”) Cerametallic-cone, 

magnetically shielded, cast aluminum 

frame woofers 

Crossover frequency: 1.40 kHz 

Connection: 

2 sets of binding post speaker terminals; 

bi-wirable 

Enclosure Material: MDF 

Finish: 

Galaxy Black cabinet. 

Black anodized aluminum fascia 

Product Weight: 17.7 kg (39 lbs) 

Cabinet Dimensions 

(H x W x D): 38.1cm x 43.2cm x 31.8cm (w/ grille) 

(15” x 17” x 12.5”) 

KL-525-THX Back Surround Speaker 



Frequency Response (-3 dB): 80 Hz to 20 kHz 

Bass Principle: Totally enclosed box 

HF Driver: 


driver. Magnetically shielded. Coupled with 

rectangular 90º x 60º Tractrix horn 

LF Driver: 

(2) 13.3cm (5.25”) Cerametallic-cone, 

magnetically shielded, cast aluminum frame 

woofers 


Connection: 

2 sets of binding post speaker terminals; 

bi-wirable 


Finish: 



Product Weight: 14.5 kg (32 lbs) 


(H x W x D): 32.4cm x 40.6cm x 31.8cm (w\ grille) 

(12.75” x 16.0” x 12.50”) 

Klipsch THX Ultra2 Home Theater Loudspeaker System 

KS-525-THX Side Surround Speaker 



Frequency Response (-3 dB): 80 Hz to 20 kHz 

Bass Principle: Totally enclosed box 

HF Driver: 


drivers with neodymium magnet structures. 

Magnetically shielded and coupled to 90° x 60° 

Tractrix ® Horns in a WDST Array 

LF Driver: 

(2) 13.3cm (5.25”) Cerametallic-cone, 

magnetically shielded, cast aluminum frame 

woofers 


Connection: 

2 sets of binding post speaker terminals; biwirable 


Finish: 



Product Weight: 9.1 kg (20 lbs) per pair 


(H x W x D): 35cm x 33cm x 21.6cm 

(13.75” x 13.0” x 8.5”) 

KW-120-THX Subwoofer 


Frequency Response (-3 dB): 20 Hz to 200 Hz 

Bass Principle: Bass reflex; front-firing port 

LF Driver: 

30.5cm (12”) Cerametallic cone, 

cast aluminum frame driver 

Crossover frequency: NA 

Connection: 

Speakon NL2 connector 


Finish: 



Product Weight: 36.0 kg (80.0 lbs) 


(H x W x D): 51.4cm x 45.1cm x 45.1cm (w\ grille) 

(20.25” x 17.75” x 17.75”) 

KA-1000-THX Amplifier 

Type: 

2-channel, Class D digital power amplifier 

Frequency Response (-3 dB): 20Hz-1kHz +0/-3dB 

FTC Rated Power: 500W into 8 ohms, 1000W into 4 ohms, 

20Hz-1kHz 

Power Control: Master and Auto-on/off 

Phase Control: Continuously variable, 0º - 180ºs 

Equalization/Response 

Compensation: Boundary-gain compensation (LF extension 

adjustment) 

THX Function: Switchable, On/Off 

Crossover Function: Continuously variable, 40Hz – 120 Hz 

Gain Control: 

Continuously variable 

Connection: 

RCA line-level input/output, 

Speakon NL2 connector speaker level output 

Cooling: 

Passive 

Finish: 



Product Weight: 12.3 kg (27.0 lbs) 


(H x W x D): 12.1 cm 44.5 cm 31.1 cm 

(4.75” x 17.5” x 12.25”) 

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Figures 7a - b are a couple images of the 

driver extracted from the cabinet, now sitting 

on top of it. Once out of the cabinet it was 

easy to see why the unit was so weighty. The 

motor assembly is an interesting structure with 

an interesting history. Kerry Geist, an engineer 

at Klipsch, wrote in response to my question 

regarding the possibility the motor assembly was 

originally designed for use in a larger drive: 

“Yes, the KW-120 uses essentially the same 

motor assembly as one of our 15” subwoofer 

drivers. However, the motor structure was 

further improved by adding a copper shorting 

ring to the yoke to reduce the distortion caused 

by variations in voice coil inductance. 

The advantage of using an existing motor 

design was simply a matter of using a design we 

already had experience with, and felt we didn’t 

need a huge engineering effort to develop into 

a 12” high-displacement version. We already 

had plenty of engineering hours wrapped up in 

the original 15” design...we were just using that 

“developed” platform as a jumping off point to 

develop the 12” THX version. The displacement 

and power handling requirements between the 

two drivers were very similar...it was an easy 

choice to make. 

Other than the shorting ring modification, 

I’m not aware of any other changes to the 

motor assembly itself. The soft parts of the 

driver (cone, suspension, dust-cap, etc…) and 

housing were different of course. As far as I 

can remember, the voice coil design is different, 

but they’re both based around a 3” diameter / 

2” coil length format.” 

Figure 8a - b: 

Klipsch KW-120 Cabinet Interior 

Set-Up 

Each carton was maneuvered to a spot on the 

home theater floor approximately where each 

speaker would eventually find its final location. 

Each item was quickly & easily unpacked and 

the cartons stowed away elsewhere. 

Editorial Note on 

Subwoofer Placement 

Subwoofer placement can be a tricky business. 

Fortunately, there are readily available many 

resources - codified as recommendations, practices 

or standards – to assist in choosing the best location 

for your sub Of course, there’s always available the 

wherever-they-sound-best-to-you approach. But if 

you’re interested in applying a more organized 

approach to subwoofer placement, have a look at: 

Subwoofer Placement Guidelines 

Subwoofer Calibration – The Place for Bass 

Part 1 

For helpful information about THX in general 

see also: 

THX Select and THX Ultra2 Certification 

General Questions 

There are a number of guidelines (many 

available online) which provide ample guidance 

for setting up a THX-certified home theatre 

system. In this case, you won’t have to look 

far for setup “How to’s” as the Owner’s Manual 

provides all the basics in terms of properly 

arraying the speakers around your listening 

space. The actual final position for the various 

speakers making up the system was very much 

like that shown in Figure 9, with the exception 

of the two subwoofers: In the end they were 

positioned directly beneath the front L & R 

speakers. If you plan on mounting the KS- 

525s flush against the wall be prepared to carve 

out a relief cutout so as to accommodate the 

protruding binding posts. 

Looking inside the now driverless cabinet, 

we get a great view of the interior. (Though 

not evident in any of the photos, the faceplate 

is double-thickness). There are a number of 

interesting features. 

The cabinet is cross braced. The brace itself 

spans the top, bottom and side panels. It also 

serves 

to secure the substantial motor structure of 

the driver. The brace, along with the cabinets 

various panels, are reinforced with glue blocks 

placed throughout. 

In the background of Figure 8a - b can be 

seen the interior end of the cabinets duct. The 

exterior end of the duct can be seen at the top 

of cabinet’s faceplate in Figure 3. The duct is in 

fact a collection of panels built into the interior of 

the cabinet, running parallel to the top and back 

panels. The interior end of the duct opens at a 

point just above the Neutrik input jack position 

on the back panel. The duct also serves as a 

useful handhold, which comes in handy when its 

time to move the cabinets around. The cabinets 

were not stuffed. 

Figure 9: Speaker disposition as suggested by Klipsch Manual 

 

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Listening Tests 

Walk into a Hard Rock café or a Malco, 

Krikorian, Harkins, Clearview, United Artists, 

or Regal cinema anywhere on planet Earth and 

you will likely hear Klipsch systems in action. Go 

see a concert in an arena or stadium and you 

will hear horns in action. It seems quite sensible 

– the idea of bringing the horn-loaded systems 

technology used in commercial cinemas into a 

home theatre setting. How well does it work in 

practice? 

The 5 DVDs (and CD) listed below were 

chosen from several dozen disks that were used 

during the course of the review sessions; each 

chosen because in one way or another they 

demonstrated various individual performance 

characteristics that when taken together 

conveyed a sense of the system’s overall 

performance. 

Top Gun, sounded like, well, Top Gun, a 

movie made twenty years ago. I happened to be 

living in southern California when the movie was 

first released and I saw it a couple of times in 

LA and Orange County. 

At one point in the movie there’s an audio 

scene where the sound of a fighter jet pans 

overhead, crossing the listening area. In those 

LA and Orange County commercial cinemas 

the pan sounded clear, focused and smooth. 

“The THX Ultra2 

is simply amazing 

in terms of sheer 

musicalness, its ability 

to deliver exceptional 

dynamics and clean, 

unadulterated detail.” 

Mark Sanfilipo 

Another words, it worked. My experience has 

been that lesser systems tend to botch the pan, 

typically sounding like the jet simply faded out 

in one part of the soundstage and faded in at 

another, without the audible sense of it crossing 

smoothly between the two points. 

I was particularly interested to see how the 

Klipsch system would handle the pan, specifically 

because of the horns used in the systems 

- including the back & side surrounds. Horns 

are synonymous with controlled dispersion, yet 

current surround sound thinking indicates a 

diffuse sound field for the surround channels 

is essential for authentic rendering. It would 

seem that controlled dispersion and diffuse 

sound fields are a means contradictory to the 

ends. The Klipsch solution? Wide dispersion 

Sound Technology (WDST). According to 

Klipsch, “By aligning two horns at 90° with 

respect to each other, along with a front-firing 

woofer, WDST surrounds smoothly cover a 

180° horizontal arc. The surround points at you 

no matter where you are seated, drawing you 

into the middle of the action.” When put to 

the test, WDST worked and the Klipsch sailed 

through this challenge with ease; the pan was 

just as clear, focused and smooth as it was 

intended to sound. 

The Hendrix DVD was chosen for the dialog 

that runs throughout much of the movie. Dialog 

can be quite a challenge for any speaker 

system; particularly so for those systems that 

make use of horns. Lesser quality horns (or 

even top quality horns used incorrectly) impart 

a nasally, honky quality to dialog. Occasionally 

you’ll even hear this in theatres that otherwise 

deliver superb sound to the listener. 

I didn’t hear the Klipsch system impart any 

sort of annoying nasality or honkiness to any 

of the dialog at any point in the movie. This 

was, of course, in part due to the decent gear 

upstream of the speakers. But the lions share of 

credit needs to go to the Klipsch speakers. With 

a respectably smooth response, the judicious 

choice of crossover points (measurements below) 

and the functional abilities of a Tractrix horn, its 

understandable how a horn-loaded system could 

review 

deliver such a high quality subjective impression. 

The dialog was consistently natural, engaging, 

and very clean. 

Top quality sound systems are ruthless in 

exposing poor quality media. Ask anyone who 

owns one and they will tell you how quickly such 

a system will reveal a particular recording’s faults 

& flaws. Rush’s R30 DVD is an example of just 

such a recording. 

Prior to auditioning the DVD using the Klipsch 

system I had listened to it a few times on a very 

average system and the DVD sounded average; 

nothing especially good or bad about it. Played 

back on the Klipsch system and the impression 

was altogether different. The Klipsch revealed 

the audio tracks as sounding very, very heavily 

compressed, taking away much of the dynamics 

that are a critical part of the excitement of live 

entertainment - or attempts to reproduce the 

moment in a home setting. 

Enjoy the Rails! is a CD that has lately 

become a favorite of mine for testing subs. It’s 

an interesting disc, comprising a collection of 

well executed recordings of diesel locomotives, 

made at close range and with a bare minimum of 

processing. That’s a combination likely to appeal 

to both audio purist and railroad enthusiast 

alike. 

If you’ve ever stood beside railroad tracks 

as a diesel locomotive thundered by you’ll be 

familiar with the earth-jiggling power of these 

mechanical giants. All the recordings contained 

in the CD were made at a distance of 1 – 3m 

meters and carry sustained, substantial amounts 

of just the sort of LF & ELF content that subs 

are made to reproduce. Even if you’re not a 

railroad enthusiast, these are exciting recordings 

to listen to. 

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Played back through the pair of KW-120s, 

the tracks shook the immediate vicinity just as 

you’d expect a diesel locomotive to do if it were 

passing by a few meters away. There was an 

almost palpable “realness” to the sound filling 

the listening space and the subs quite capably 

defined the presence of those hundreds of 

virtual tons of heavy metal trundling through 

the room. 

Of all the loudspeakers comprising the 

Klipsch THX Ultra2 system, the subs were 

the biggest surprise of all. They look so utterly 

civilized, yet when called to duty they can kick 

& roar with masterful authority. As capable as 

they are at dumping eye-popping amounts of 

acoustical energy into a listening space, they 

don’t overwhelm or overplay as some subs tend 

to do. They don’t butt in to audio scenes where 

they don’t belong. They integrate seamlessly 

with the rest of the system and having two 

cabinets helps immensely when it comes to 

finding suitable placement when dealing with 

room modes. 

Klipsch opted to build the power amp separate 

from the subwoofer cabinet; the amp is a stand 

alone unit that jacks into the subs via the 

supplied 6m (20’) long, Neutrik Speakon plug 

tipped, cables (See Figure 5b). 

Providing a separate power amp is a major 

convenience, and especially helpful for those 

who opt to build their system into the walls of 

their home theatre. Even if you have no plans 

to build your speakers into or onto the walls of 

your home theater, racking up the KA-1000 

along your AV receiver provides other benefits: 

If you’ve spent too much time crawling around 

behind your sub tweaking this or that setting, 

perhaps by flashlight, you’ll especially appreciate 

“Klipsch has managed 

to carry forward 

decades of home and 

professional cinema 

sound experience 

and bundle it all 

into one brilliantly 

executed system.” 

Mark Sanfilipo 

having the sub’s power amp close at hand. 

No more hanging out behind your sub in that 

forgotten zone where dust, lost toys and the 

occasional house pet gather while you tweak 

away in search of the perfect splice. 

The cable that comes with the subs is worth 

mentioning in further detail. They cables sport, 

as already mentioned, Neutrik Speakon plugs. 

I see these connectors used all the time in 

pro audio situations. This, however, is the first 

time I have encountered them in a home audio 

application. Excellent! The cable is made up of 

four 16 gauge wires, paired at the connector 

end, resulting in a very flexible 13 gauge cable. 

The Neutriks are sturdy, pretty much foolproof, 

can handle prodigious amounts of current (30 

A!) and feature self-cleaning contacts. This is 

yet another example of the nice (functional) 

touches found in the Klipsch Ultra2 THX system 

that help separate it from run of the mill 

products. 

If I had only one DVD by which to review 

this system Eric Clapton’s Sessions for Robert 

J. would be my choice. The DVD from the 

two disk DVD/CD suite thoroughly explores 

the outer reaches of the Ultra2 THX system’s 

performance envelope, giving the system the 

chance to showcase its talent to the max. 

Each of the four previously mentioned discs 

illustrated individual components of the system’s 

performance abilities. The Sessions for Robert 

J. DVD would help provide the answer to 

the all-important, over-arching question: how 

authentic a reproduction is this system capable 

of delivering? All the right ingredients were 

certainly in place for the magic to happen once 

“Play” was pressed. 

The Sessions for Robert J. DVD/CD suite 

is a collection of material originally written & 

performed in the 1930’s by Robert Johnson, 

an American blues musician, now performed 

by Eric Clapton and company. The production 

values found in this compilation are excellent, as 

is the musicianship. The tracks were recorded 

at four separate locations, a recording studio 

in England, a studio in Irving, Texas, a nowabandoned 

film distribution building in Dallas 

and a beach front hotel room in southern 

California. 

Once I’d gotten hold of a copy of the DVD it 

went straight to the top of my play list. Simply 

put, no other DVD gave the Ultra2 THX system 

the chance to show off its stuff like this one 

did. The collection of tracks done at the top of 

the DVD sounded so authentically lifelike when 

played back through the Klipsch that I found 

myself viscerally reacting as though I were 

sitting through the zillionth sound check of my 

sound guy career – in my home theater! 

Right at the top of “Sweet home Chicago” 

track they set hi-hat levels with Eric shouting 

instructions back to the board op as the 

drummer tapped out measure after measure 

of kick/snare/high-hat. I kept listening to that 

segment of the track over and over at levels 

typical for a band playing in a space the size 

of the studio it was recorded in. The more 

I listened, the more apparent it became the 

Klipsch speakers were reproducing a musical 

event, in a way, that at times, sounded closer 

to the real thing than I’ve ever heard a home 

theatre system do before. All the benefits to be 

gained in using horns - controlled dispersion, 

higher than average sensitivity and low distortion 

(so long as they’re not pushed to hard) – came 

into play here and contributed to the authenticity 

of the moment. What a tremendous technical 

achievement – hats off to all at Klipsch who 

played a role in designing and/or manufacturing 

this superb loudspeaker system. 

Now what about the “so long as they’re not 

pushed to hard” bit? Any horn, pushed too hard, 

will spray the listening area with obnoxious 

amounts of distortion. You’ve probably been 

exposed to just this type of horn-pushed-too-far 

distortion last time you saw an arena concert 

played through a too-small system, paired 

back, perhaps, to keep expenses down. If 

management deems it necessary to leave half a 

semi’s worth of FOH (front of house) speakers 

behind then everything that’s left has to work all 

the harder to keep levels up. Ouch! 

What about the Klipsch horns? Yep, they can 

be pushed into the obnoxious distortion zone, 

but only when driven at levels no one would 

want to expose themselves to for very long. Go 

back and look at those sensitivity figures again 

– this system knows how to play REALLY LOUD 

and enjoy every minute doing so - without having 

to be pushed into the obnoxious distortion zone. 

Indeed, in all the dozens and dozens of hours 

spent listening to this system I never needed 

to push the system into that particular zone. It 

was so capable of playing so loudly and cleanly 

without being pushed beyond its limits. 

 

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Conclusion 

The THX Ultra2 is simply amazing in terms 

of sheer musicalness, its ability to deliver 

exceptional dynamics and clean, unadulterated 

detail. It’s a system that proves once and for 

all you can bring, in an authentic way, the bigscreen 

cinema sound experience to your home. 

It will again and again surprise you in ways that 

define the exceptional listening experience. 

The Klipsch Ultra2 THX 7.1 home theater 

system gives the consumer the opportunity 

to reap the benefits of a product built on 60 

years of engineering expertise and technological 

refinement. All in a package that can fit into your 

home theater. 

With the THX Ultra2, Klipsch have managed 

to carry forward decades of home & professional 

cinema sound experience and bundle it all into 

one brilliantly executed system. If you’re ready 

to move up to a THX Ultra2 system and plan on 

making the rounds of all your local audio salons 

with audition list in hand, put this system at the 

top of that list. You’ll save yourself an awful lot 

of audition time. 

By Mark Sanfilipo 

Email - info@audioholics.com 

Klipsch 

3502 Woodview Trace, Suite 200 

Indianapolis, IN 462 

Toll-free: 800.Klipsch 

www.klipsch.com 

Non-exclusive reprint rights have been provided to 

Klipsch to reprint and freely distribute this review. 

Any other uses or instances of this review by other 

parties or by Klipsch are prohibited without prior 

approvals from Audioholics. The original review can 

be viewed online at www.audioholics.com 

Klipsch THX Ultra2 Home Theater 

Loudspeaker System Score Card 

The scoring below is based on each piece of equipment doing the duty it is 

designed for. The numbers are weighed heavily with respect to the individual 

cost of each unit, thus giving a rating equal to: 

Performance x Price Factor/Value = Rating 

Audioholics.com note: The ratings indicated below are based on subjective 

listening and objective testing of the product in question. The rating scale is 

based on performance/value ratio. If you notice better performing speakers in 

future reviews that have lower numbers in certain areas, be aware that the value 

factor is most likely the culprit. Other Audioholics reviewers may rate speakers 

solely based on performance, and each reviewer has their own system for 

ratings. 

Audioholics Ratings Scale: 

Outstanding (reserved for features or areas that exceed market norms) 

Above Average 

Average 

Below average 

Very poor 

Metric 

Build Quality 

Appearence 

Rating 

Treble Extension 3 

/4 

Treble Smoothness 1 

/2 

Midrange Clarity 

Midrange Accuracy 

Midbass Extension 

Bass Extension 

Bass Accuracy 

Imaging 

Soundstage 3 

/4 

Overall 3 

/4 

Value 

Associated Test Gear 

Hardware 

Koss KS-5116 

Denon AVR-3806 

Monster Cableage 

LinearX LMS 4.5 

Hewlett - Packard 3455A 

Description 

DVD Player 

AV Surround Receiver 

Interconnects & Miscellaneous Other Cabling 

Measurement Suite 

Digital Multimeter 

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Measurements and Analysis 

Figure 10: 

KL – 650 – THX Front LCR Speaker System 

Impedance Magnitude Curves 

Figure 11: 

KL – 525 – THX Back Surround Speaker System 


Figure 12: 

KS – 525 – THX Side Surround Speaker System 


Figure 13: 

KW – 120 – THX Subwoofer Speaker System 


Figures 10 – 13 are impedance curves for the various systems 

making up the Klipsch Ultra2 THX home theater system. In Figures 

10 & 13 we see the typical saddle-shaped curve at the left, with 

the impedance minimum (5.3 Ω @ ~ 56 Hz for the KL-650 and 

6.7 Ω @ ~ 25 Hz for the KW-120) in each case indicating the 

vented box tuning frequency. In Figures 11 & 12, the closed box 

tuning frequency is indicated by the impedance peak (32.6 Ω @ ~ 

83 Hz for the KL-525 and 41.6 Ω @ ~ 107 Hz for the KS-525). 

The second peaks, seen towards the right in Figures 10 – 12 

typically arise as a result the interaction of the crossover network’s 

high- and lowpass sections, setting up a parallel resonance. 

The global impedance minimum for the KL-650, KL-525, KS- 

525, and KW-120 are (respectively): 3.2 Ω (averaged), 4.2 Ω, 

3.6 Ω, and 6.7 Ω. The respective system nominal impedance (per 

IEC standards) are therefore 4 Ω, 6 Ω, 4.5 Ω, and 8 Ω. Obvious 

from the measurements, no system ever went below 3.2 Ω, as 

per THX requirements. 

The impedance phase swings between +40˚ and -60˚ (KL-650), 

+41˚ and -64˚ (KL-525), +60˚ and -65˚ (KS-525), and -46˚ and 

climbing towards 90˚ (KW-120). The impedance minima might 

give cause for concern, but keeping in mind the phase angle at 

the minima and the high sensitivity of the KL-650, KL-525, and 

KS-525 the systems shouldn’t prove to be a difficult load for most 

AV receivers, especially THX Ultra2 certified ones. 

 

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review 

Figure 14: 

KL – 650 - THX system amplitude response, 

1m, on-axis, 2.828 Vac drive level 

Figure 15: 

KL- 650 grill cloth effect on system amplitude response. 

Derived from measurements taken with and 

without grill cloth, 1m, on-axis, 2.828 Vac drive level. 

Figure 16: 

KL – 525 - THX system amplitude response, 


Figures 14, 16, 17, and 18 show the amplitude response of the 

frequency response of the KL-650, KL-525, KS-525 and KW- 

120 systems, obtained by the application of gated, near field and 

ground plane measurements, as appropriate, scaled to 1m. 

The relative flatness of the response curves (particularly with the 

KL-650 & KL-525s) underscores the tonally balanced & sonically 

accurate presentation of this very impressive system. It’s easy to 

see how the musicalness (ability to accurately render the timbre of 

individual instruments) of the system is as outstanding as it is. 

The grill cloth used by Klipsch is, acoustically substantially, 

substantially transparent. Figure 15 shows a comparison between 

dB spl measurements made with and without grill cloth in place. 

A perfectly transparent grill cloth would have produced a ruler-flat 

line, centered at 0 dBr. As it is, the curve is very flat and better 

than some I have seen of systems costing far more than the 

Klipsch Ultra THX2. 

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eview 


Figure 17: 

KS – 525 - THX system amplitude response, 


Figure 18: 

KW – 120 – THX single subwoofer amplitude response, 

scaled to 1m, on-axis, various voltage drive levels 

Figure 19: 

KW – 120 – THX dual subwoofer amplitude response, 

scaled to 1m, on-axis, various voltage drive levels 

The KW-120 were measured outdoors, using the ground plane 

technique. The initial measurement was made at 2.828 Vac drive 

level and increased incrementally. The dB spl curves showing 

in Figure 18 are for 1 sub, Figure 19, 2 subs. (Note: some of 

the curves look messy in the 10–15 Hz segment; thisis due to 

environmental noise and should be ignored).Pairing 2 KW-120s 

and firing their combined acoustic output into 1/8th space (ie, 2 

KW-120s placed side by side in a corner of a listening room) and 

the dB spl levels listed in the Klipsch spec sheet are reasonably 

obtainable. 

10 www.audioholics.com

Klipsch THX Ultra2 Home Theater Loudspeaker System Review

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