Klipsch La Scala AL5 loudspeaker Measurements

Sidebar 3: Measurements

Because of the Klipsch La Scala's bulk—it weighs 201lb—I measured the speaker in AH's apartment. I used DRA Labs' MLSSA system and a calibrated DPA 4006 microphone to measure the La Scala's behavior in the farfield, and an Earthworks QTC-40 mike for the nearfield and in-room responses. The loudspeakers were driven by the Manley Mahi Mahi amplifiers AH used for his auditioning. For the measurements, I left off the grille that covers the high-frequency and midrange horns, as AH preferred the sound without them.

The La Scala's sensitivity is specified as an extraordinarily high 105dB/2.83V/m, which is the same specification as the Klipschorn AK6 that the late Art Dudley reviewed in September 2019. As with the AK6, my B-weighted estimate was lower, at 101.3dB(B)/2.83V/m, but this is still the second-highest sensitivity of all the speakers I have measured and almost 19dB higher than the sensitivity of the BBC LS3/5a I always measure at the same time I test a speaker (to ensure that I haven't made an error in setup). This speaker will play loudly even with a flea-powered amplifier driving it.

Fig.1 Klipsch La Scala, electrical impedance (solid) and phase (dashed) (2 ohms/vertical div.).

Klipsch specifies the La Scala's nominal impedance as "8 ohms compatible." However, the speaker's impedance magnitude (fig.1, solid trace) drops to 4.23 ohms at 70Hz and 4.17 ohms at 335Hz, and the electrical phase angle (dotted trace) is sometimes high. The equivalent peak dissipation resistance, or EPDR (footnote 1), drops below 3 ohms between 10Hz and 40Hz, 58Hz and 93Hz, 325Hz and 490Hz, and 4kHz and 11.5kHz. The minimum EPDR values are 2.1 ohms at 63Hz and 8kHz and 1.9 ohms at 372Hz. The La Scala will work best with amplifiers that are not fazed by 4 ohm loads, but the need for current will be alleviated by the Klipsch's very high sensitivity.

Fig.2 Klipsch La Scala, cumulative spectral-decay plot calculated from output of accelerometer fastened to center of woofer bin side wall (measurement bandwidth, 2kHz).

The treble and bass enclosures' side and rear panels sounded lively when I rapped them with my knuckles, so I investigated the panels' vibrational behavior with a plastic-tape accelerometer. While the treble enclosure was free from resonances in the midrange, where they might have had an audible effect with music, I found three fairly strong resonant modes on the sides of the bass bin (fig.2). The highest was at 125Hz.

Usually when I measure a loudspeaker's farfield behavior, I raise it as far as possible off the ground. This moves the reflections from the floor back in time and increases the resolution of the FFT-derived responses in the midrange. (The FFT is applied to the portion of the impulse response before the first reflection of the sound.) However, even with AH's help I couldn't lift the La Scala off the floor onto a stand, so to increase the effective analysis time window, I measured the farfield behavior at 1m rather than my usual 50".

Fig.3 Klipsch La Scala, step response on tweeter axis at 1m (6ms time window, 30kHz bandwidth).

I then had to deal with another issue. As with the Klipschorn AK6, when a loudspeaker uses horn-loaded drive units, but the horn openings are all in the same plane, the outputs of the drive units arrive at the microphone or the listener's ears at different times due to the different lengths of the horns. This can be seen in fig.3, which shows the La Scala's step response on the tweeter axis. All three drive units are connected in positive acoustic polarity, but the tweeter's output arrives first at the microphone. The output of the midrange unit doesn't arrive at the microphone for another 1.5ms, while the woofer's output starts to arrive 2ms after that. Although the arrivals of all three horn outputs are within the ear's tolerance for arrival time difference (footnote 2), such behavior could interfere somewhat with stereo imaging precision.

Fig.4 Klipsch La Scala, acoustic crossover on tweeter axis at 1m, corrected for microphone response, with the nearfield midrange (red) and woofer (blue) responses plotted below 500Hz.

The La Scala's impedance-magnitude plot has a single peak in the bass centered at 52Hz, suggesting that this is the drive unit's fundamental tuning frequency. Klipsch specifies the speaker's low-frequency extension as –4dB at 51Hz, which was confirmed by a nearfield measurement (fig.4, blue trace): The woofer's output rolls off below that frequency. I also saw peaks in the woofer's output in the octave between 100Hz and 200Hz. The woofer crosses over to the midrange unit (fig.4, red trace) close to the specified 450Hz, with a relatively sharp upper-frequency rolloff.

The midrange unit rolls in quickly, and while its farfield output (fig.4, red trace) has a touch too much energy in the upper midrange and close to 3kHz, its balance is relatively even. Although the tweeter does not have a separate input, because of the arrival time differences seen in fig.3, I could perform separate high-frequency FFT analyses for the midrange unit and the tweeter. The red trace above 3kHz in fig.4 shows the midrange unit's response calculated in that manner, while the green trace shows that of the tweeter. The upper-frequency crossover appears to occur at 4kHz rather than the specified 4.5kHz, and the tweeter appears to be balanced approximately 3dB too high in level before it rolls off quickly above 19kHz.

Fig.5 Klipsch La Scala, midrange/treble enclosure, anechoic response on tweeter axis at 1m, averaged across 30° horizontal window and corrected for microphone response.

Fig.5 shows the farfield response of the La Scala's upper enclosure averaged across a 30° horizontal window centered on the tweeter axis. The tweeter still appears to be too high in level compared to the midrange unit's top-octave response, and there are some sharply defined suckouts at the top of the midrange unit's output. Note that I didn't connect the woofer for this measurement, as its output was corrupted by the reflections from the floor.

Fig.6 Klipsch La Scala, lateral response family at 1m, normalized to response on tweeter axis, from back to front: differences in response 60–5° off axis, reference response, differences in response 5–60° off axis.

Fig.7 Klipsch La Scala, vertical response family at 1m, normalized to response on tweeter axis, from back to front: differences in response 15–5° above axis, reference response, differences in response 5–10° below axis.

For the same reason, the plot of the La Scala's horizontal dispersion (fig.6), normalized to the response on the tweeter axis, shows just that of the midrange/treble enclosure. (As the graph with my usual 1/10-octave smoothing was too complicated to easily see what was happening off-axis, I used 1/3-octave smoothing.) The speaker's horizontal dispersion is relatively uniform with frequency and gently falls off to the speaker's sides. In the vertical plane (fig.7), the response on the tweeter axis, which is 38" from the floor, is maintained over a ±5° window.

Fig.8 Klipsch La Scala, spatially averaged, 1/10-octave response (red) and of the JBL 4367 Studio Monitor (blue) in AH's listening room.

The red trace in fig.8 shows the Klipsch's spatially averaged response in AH's room. To generate this graph, I average 20 1/10-octave–smoothed responses taken individually for the left and right speakers in a vertical rectangular window centered on the position of the listener's ears. The averaging tends to minimize the effect of room resonances on the measured response below 400Hz. For reference, the blue trace in this graph shows the spatially averaged response, taken in the identical manner, of the JBL 4367, which AH reviewed in May 2022. The traces are adjusted to be equal in level at 1kHz, but it should be noted that the JBL's measured sensitivity, though high, is 10.6dB lower than the Klipsch's. The La Scala has a little more output than the JBL in the top two octaves and the lower midrange, but its low frequencies are in better balance, despite the speakers being in very similar positions in the room. As expected from its nearfield response (shown in fig.4), the La Scala's low frequencies roll off in-room below 50Hz.

Fig.9 Klipsch La Scala, midrange unit only, cumulative spectral-decay plot on tweeter axis at 1m (0.15ms risetime).

The differences in arrival times of the three drive-unit outputs make a conventional cumulative spectral-decay or waterfall plot very difficult to interpret. However, the different arrival times make it possible to calculate individual waterfall plots. The tweeter's waterfall plot (not shown) revealed a clean initial delayed energy, with some ridges of delayed energy at the top of its passband. Fig.9 shows the midrange unit's waterfall plot. It is fairly clean, though a ridge of delayed energy is visible just before it crosses over to the tweeter. Several energy spikes are visible above the crossover frequency, but these are low in level.

The La Scala's measured behavior is complicated, but from my experience listening to music in AH's room, its balance is more neutral than I was expecting. And I remain astonished by that high sensitivity. Even though I had MLSSA's output set to its lowest level when I performed the measurements, the sound was very loud. I was concerned that AH's neighbors would eventually be knocking on his door to complain!—John Atkinson

Footnote 1: EPDR is the resistive load that gives rise to the same peak dissipation in an amplifier's output devices as the loudspeaker. See "Audio Power Amplifiers for Loudspeaker Loads," JAES, Vol.42 No.9, September 1994, and stereophile.com/reference/707heavy/index.html.

Footnote 2: See https://en.wikipedia.org/wiki/Precedence_effect.

Klipsch Group, Inc.
3502 Woodview Trace
IN 46268
(317) 860-8100

remlab's picture

I was definitely not expecting to see that.

georgehifi's picture

It's -10dB down at 45hz for a speaker the size of a fridge!!!! with a broadband bump at 150hz of +5db to make up for it.
I owned a pair of the originals to see what all the hoo-ha was about, sure they went loud without too much stress (so does a PA system) but boy were they colored, they lasted a couple of weeks.

Cheers George

carewser's picture

In fairness to Klipsch I mean how much bass can one expect when you only spend $13,000 for a pair of speakers?

m_ms's picture

Price has no bearing here, but rather physics as laid out by Hoffman's Iron Law:

"three parameters that cannot all be had at the same time. They are low-bass reproduction, small (enclosure) size, and high (output) sensitivity." Hofmann stated that designers could pick two of these three parameters, but in doing so, it would compromise the third parameter."

The La Scala's are a high efficiency, (all)horn-loaded design, and their restricted size for a bass horn means you sacrifice low end extension. Not only that they also stop acting as a horn from just above 100Hz on down, which means they're essentially too small as a midbass horn also. With horns, all-horns not least and certainly for them to be their best, there's no escaping size.

remlab's picture


jack_lint_1984's picture

On behalf of the International Committee on Complaining, I wanted to personally commend you, George, on your performance here - ever diligent, never satisfied.

Bravo! As we like say in the trade, pleasure is overrated!

Glotz's picture

Well put. George still has a lot to offer.. just delivery methods.

jimtavegia's picture

My favorite has always been the Cornwall, but I have never lived in a house with a living room large enough that would make them work, sadly. I have heard them sing with a small 40 watt/channel EL34 tube amp.

DougM's picture

The La Scalas, and the mighty K'Horns, are more capable than any others of bringing the performance into your room, with an immediacy and effortless dynamism that sounds more like live music than any other speaker I've ever heard at any price. My bucket list speaker.

Toobman's picture

The warranty is 10 years, not 5 as stated in the specifications. Also, there are no rubber feet supplied as the reviewer stated. I know because I just bought a pair. Further, I set the speakers up all by myself and it was not difficult. I'm 58 and in average shape. I can't imagine why the reviewer would suggest it takes 3 people to mate the upper and lower cabinets.

michelesurdi's picture

horns amplify noise.were the scalas silent with the amps you mention?

FransZappa's picture

I'd like to ask you how
You like the feel of the bass in your face in the crowd

I have bought my Scala's about three years ago and they have never ceased to amaze me. My amp is an Elekit TU8600R - 300B and 9.2Wpc and my room is not exactly big. Believe me: it does do bass, not stomach turning low but very real life like bass. Gary Peacock is standing in front of you - like bass. It plays the Beasties and Aphex Twin and never has anyone sitting next to me commented about a lack of bass. Tom Waits' scrapyard percussion sounds fantastic and they unravel Zappa's genial madness brilliantly. And the Scalas are deadquiet with my amp. The last speakers I will ever need.

vince's picture


Try a sub, I tried a JL Audio Fathom and it brought a new level of enjoyment of my La Scala.

ejlif's picture

I agree, I have a pair of older ones and have had a lot of other speakers and stuff costing way more and with the La Scala it's like it really happening in front of you. For me the bass is good and almost but just not quite enough, sometimes it's fine other times I feel it's lacking a little. I added a HSU sub and it works good, it's the first time I've had a sub and been able to stand it.

Toobman's picture

Why does the reviewer say they can be bi-wired but not bi-amped? One set of posts goes to the mid/hi drivers and the other set goes to the woofer, so they should be able to be biamped.

Alex Halberstadt's picture

Thanks for the catch, Toobman. My mistake. I'll make the change.


FredisDead's picture

my enduring love for the Manley Steelhead until I read this piece of audio journalism dreck. I immediately concluded that Jim Austin must have decided it would be "cute" to review some audio icons-of-yore and even cuter if they were given rave reviews. How would that not create some stir among the ol' geezer subscribers?
As it so happens I recently heard a newer set of these speakers and I could not get over how they sounded-old, tired, slow, soporific (Ambien soporific) outdated, disassociated, discontinuous, unnatural, etc. Dynamics? What good is lack of compression when you are overwhelmed by crass treble, scratchy midrange, and soft bass, all failing to integrate and instead sticking out like three sore thumbs?
Which leads to only one inevitable head scratching inquiry-has Stereophile truly, once and for all, jumped the shark?

jack_lint_1984's picture

Have you ever been to an arena sporting event? If you have, you’ll have noticed certain people in the crowd screaming at the players, as if their opinions are more important than the action unfolding in front of them. As if the professionals should stop play and pay attention to every voice in the crowd.

You, FredisDead, are one of those screaming fans.

FredisDead's picture

I don't yell at players, don't go to arena sporting events, don't drink beer, and don't know what rock you crawled out from either. Am I such a person in your tiny mind for expressing a different view and relating it to editorial policy? It is simply ludicrous to call the La Scala competitive with modern designs and I chose to express my opinion here where the piece originated. This is a subjective hobby but it is hard to imagine that most would find this product capable of providing a fraction of the performance of most modern designs. I happen to be a fan of easy to drive efficient loudspeakers and my personal choices (Devores and Spendors)are 93 db/W/M and 90 db/W/M efficient without difficult phase angles or impedance curves. I simply disagree with the flowery language used to describe their sound.

rschryer's picture

"...the flowery language used to describe their sound." You should've started with that.

jack_lint_1984's picture

You are the kind of person who acts like a childish bully hoping it makes you seem less...Defensive? Sensitive? Afraid?

You disagree with the reviewer and prefer your choices in speakers. Not exactly revelatory stuff, FredisDead, especially without all of your flowery machismo.

georgehifi's picture

The forum cop or something??? Go away and let people have their say.
Argue the point not the person!!!!!!!!!!!!!!

jack_lint_1984's picture

Are you the forum cop, georgehifi? This is so confusing ;-)

georgehifi's picture


georgehifi's picture

No look at it again, YOU JUMP ON MEMBERS PERSONALLY if you don't agree with them, instead of opposing their statements with something tangible from your mouth.

jack_lint_1984's picture

FredisDead's comment was pure dreck and I have to wonder if he was just trying to be "cute" to anger the old geezers or if he's completely jumped the shark.

georgehifi's picture

It's his opinion on these Klipsch speakers, and he didn't attack YOU PERSONALLY!!!
You should do the same and attack his views on THEM NOT HIM in a subjective or objective way technically or whatever, and lay off him personally.!!! Otherwise your just being a redneck.

jack_lint_1984's picture

I just re-used his exact words. FredisDead's words. The fact that you didn't see that makes me wonder if you actually read the things you comment on...

Unless you think its OK to "personally attack" Stereophile's reviewers and Editor, you should also aim your outrage at FredisDead.

I have to point out that complaining about a perceived personal attack wherein you personally attack the perceived attacker is not a great way to make a point or set a standard of conduct.

Anton's picture

You beat me to it.

Audiophiles are an amazingly disgruntled lot. Likely the amount of rancor from a person is inversely proportional to his auditory acuity.

jack_lint_1984's picture

If so thank you, if not apologies. I'm new here, long time reader, and our grandchildren coaxed me into 'participating' so forgive my clumsiness.

Disgruntled! About hi-fi? About listening to music? I imagine it's a byproduct of free time, something that was in short supply back in the day. And on that note, this 'participating' may not be for me. Listening to music is a luxury, at least it is for me, so I've got no interest in arguing over the means to that end.

Anton's picture

Yes, I meant that as a compliment to your post!

I did not mean to impugn audiophiles, in general....just some.

Cheers, and pleased to meet you!

FredisDead's picture

just opinionated. If the loudspeaker that is the subject of this review is a "great" loudspeaker, than what loudspeaker that produces some degree of sound is not? Are any of the loudspeakers sold at large appliance stores really all that bad? How are they inferior to the La Scalas?
It is the lack of relativism that provoked my first post. If the gist of the subjective review was that they bring a lot to the table and offer plenty of good attributes despite having some shortcomings (including being huge for the sake of so-so bass response), I would have been fine with the review.
Re-reading it, I see that the lack of holographic imaging and a slight "euphonic" character is mentioned at the conclusion.
In the bigger scheme of things, my gripe is with being far too complimentary to virtually any product under review. This particular outdated, limited, and highly compromised product captured the cover of the magazine.

JHL's picture

...because demands for tolerance are never tolerant.

To extend the arena metaphor, don't be mad guy shrieking for the ref to penalize the player who finally hits back. I'm with jack: When a driveby commenter drops in just to attack the publication and its readers I assume the only tone he understands is that tone. He's declared war on everybody; who are you to impose decorum on the victims, mister punctuation?

If high end audio doesn't maintain then it won't be maintained. That would be unacceptable.

georgehifi's picture

Well your just as bad then

TK-421's picture

I've heard plenty of Spendors and they are a boring snoozefest compared to La Scalas, not to mention way overpriced for performance you get compared to others. Just expressing my opinion.

Glotz's picture

Love that phrase... I wish could've stuck 'narky' in there too. LOL, just kidding.

ejlif's picture

I'd take the La Scalas in a heartbeat over the Kef Blade 2. I owned both at the same time and I find the Kef bland and boring. We all like what we like. I'm not going to say I'm right and you are wrong, I just don't hear it like you do obviously. Some folks think the new top gun movie is a good film to those folks I would just say I won't be watching any movies you recommend. If you think the La Scalas sound that bad then I would not take a shred of your hifi advice either.

Staxguy's picture

My first loudspeakers were Klipsch Heressy Ii’s (x3) and Klipsch KG 1.2’s. The store that sold them also sold La Scalas. For bass, I had a Velodyne F1500r. At the time I would have preferrered a Carver Amazing Loudspeaker with ribbons and four 12 inch drivers per side, but couldn’t fit or budget them. Noted that I preferred the kg 1.2 bookshelf speakers for music over the heresy’.


The Klipsch horn systems really sounded honkey to me. Ok for dynamics. I much preferred a friends home theatre with 5 psb stratus gold speakers and five velodyne f1500rs, which I later upgraded to. A bit overkill in the bass though.

Obviously now, I prefer electrostatics. Quite the opposite of horns.

The new la scalas as pictured are drop dead gorgeous. Perhaps Klipsch has upgraded the sound also. The price is quite reasonable, at that of a high end phono cartridge.

My auditions at the time don’t quite pass muster, today, 30 plus years later.

I appreciate the article. As for realistic audio, the only speakers which sounded live to me were the focal grande utopia iii em, which I auditioned when they came out many years back.

Still, I wonder how a Bob carver design of today would compare to the La Scala.

Electrophone's picture

I was enthusiastic about hi-fi as a teenager, but could only afford the most basic equipment. A key experience back then was the Klipschorn demonstration in a Frankfurt/Germany hi-fi studio, which I was able to sneak into. I can still remember the track being played: "Silly Putty" by Stanley Clarke. I was deeply impressed by the dynamics and the live character of the playback. Unfortunately I don't remember which amplifier and turntable was used.
A few years later I regularly went to a small nightclub in a suburb of Frankfurt. Two Klipsch La Scala speakers were used there, suspended from the ceiling. No subwoofers! The sound was very good, the bass not too deep, but very defined and powerful.
My last encounter with Klipsch loudspeakers was in 1983 I believe.
Wolfman Jack was then on the "European Tour, sponsored by Klipsch and Phase Linear" and performed in American clubs. He also did a gig at Rhein Main Air Base and an American friend took me with him.
I still have Wolfman Jack's autograph today, and a Polaroid of me with him. I had to pay an extra $20 for the Polaroid back then, on top of the entrance fee!

scottsol's picture

While the Wolfman is long dead, he will be appearing in a late summer tour in the guise of an Elon Musk designed humaniform robot. For maximum durability the robot makes substantial use of tungsten carbide elements.

To avoid possible legal troubles with the WJ estate the simulacrum will be known as Wolfram Jack.

Anton's picture

I am so old, I can remember the 40 (or so) years when "Klipsch sucked."
They couldn't get a good word in the Hi Fi world to save their souls.

Now, they are great, again.

I look at this with some happiness and some cynicism. It's almost hard to discuss. I partially see both sides.

Is it that they figured out what they lacked was simply a healthy bump in price and that got their audiophile bonafides sorted out? Did we slowly wake up to what they do well? Is modern Hi Fi sterile or some adjective that makes us go 'pop' when we hear actual dynamics? No set answer, but great wine conversation!

When we talk money/value: These $1100 per pair in 1978.

I'll leave it to whomever to run that through an inflation calculator. It ain't like they reinvented the wheel, you know.

Anyways....I've always enjoyed them, they have plusses and minuses, of course. But all in all, a fun product! My son stole my La Scalas and is quite the happy audiophile. If you ever get a chance to hear Elvis' vesrion of "Fever" on these, you will know what the fuss is about. (They also play the band Morphine like they were made for each other. As John marks used to say, "Different horses for different courses.")

vince's picture

I have a pair of the La Scala II. I found the bass a bit lean, until I added a JL Audio sub and it became awesome. They image well, they have plenty of slam and dynamic range, and sweet sounds sweet. I have them paired with a 300B SET amp. I'm glad I have them, they can give me goosebumps, given the right recording. The latest example of this was from the Analog Production's reissue of Cat Steven's Tea for the Tillerman.

Anton's picture

I agree.

They are pretty "unboxy."

There is a certain frequency in the upper bass where you can 'hear' that there's an enclosure involved in the sound. It's a bit hard to describe. It's not 'horniness,' but almost like a hint of 'box echo' with the woofer at the upper end of it's frequency range.

You can hear this on something like Joe Jackson's "Another World" with the percussion at the beginning.

teched58's picture

So I will need a subwoofer if I want to get low bass out of my La Scala setup.

Isn't the subwoofer supposed to be the biggest speaker in the room, not the smallest?

tnargs's picture

I have twice had extended auditions with the La Scala, 30 years apart, and decided that they are one of the worst serious speakers I’ve experienced.

Sal1950's picture

Great Review Alex.
But you better run like hell.
Sam Tellig wrote a rav review on the La Scala's here in 2006 and the horn haters nearly stoned him to death.
I owned my La Scala's from 1978 to 2011 when I moved to Fl and didn't have the room for them here. Like every speaker before and since, they have their weak points and strong points. The things they do right, they do better then almost any speaker ever made.
Wish I still had the room for a pair.
cent' anni,

ejlif's picture

I was excited to see what AH thought of the La Scala. That he is a fan of Altec makes me curious. I own the La scala myself, grabbed a pair at a garage sale beat up and cheap. They really caught my attention when I hooked them up for a garage system and in the house they came and put them down in front of my Kef Blade speakers. they turned my hifi world upside down. Kefs are gone, La scala were made pretty with new veneer and cleaned up. I have more fun and enjoyment listening to my 1978 La Scala with various amps than the expensive various you name it I've had it hifi brands. Alex really sums it up with the descriptions of how music is communicated and yes the bass is a problem, just a little bit of a problem. Many times I thought I could live without a sub but they are just barely lacking. I've managed to integrate a sub (I never have liked subs) and it's just enough. Other types of speakers are nice and present music in a different way but after so many years in the hobby and so many speakers I've landed. Herb reviews and also describes why he is left cold by the tall skinny speakers. They were on to something way back in the day when they made these and other speakers like these. I think I vibe with HR and AH and Art Dudley too as well as Ken Michalief and their opinions on sound and music. JVS and even JA they come from another camp. That' great we all hear it a little different and have a different taste.

steve59's picture

My buddy was, probably still is a klipsch guy, owning the lascala’s and then the big K horns. He was so stunned when the khorns lacked the mid bass boost that he nearly returned them. I remember the lascala’s of the late 80’s having bloated, kind of thick bass, but I’ve learned setup, room size and components can make such a difference in each demo that I take it all with a grain of salt.