Klipsch Heresy IV Speaker Review

[Sal1950]

It is fricking trivial to build a high-sensitivity loudspeaker with very limited bandwidth and poor performance. It's not even hard to build one that's very efficient (i.e., skip the high-level crossover and go "fullrange"). I can do it in a half-hour with any of two dozen* "fullrange" drivers in the basement and a box. Such contrivances can be fun, but they're not hifi.

A ton of truth in what your saying.
OTOH, it was just as "fricking trivial" to design a speaker such as the highly revered LS3/5A .
A small speaker that has for it's time a relatively flat FR, but can't play loud, has loads of distortion if it
tries to do even slightly so, and no low bass. Also a "one trick pony."
Let the flames begin. LOL
I lived with my La Scala's for 32 years, and was well aware of their issues.
I tried to them improve them over that time with factory driver and crossover upgrades and tube amps.
But during all that time I never found anything that was in my budget that could replace them doing the things
that were a priority for my listening in those days.
Every speaker ever made was designed with it's own particular tradeoffs.
All things on balance the Heresy is and has been a "pretty good" little speaker.
JMHO YMMV

 

[Angsty]

but the proliferation of mods and improvements for the heritage Klipsch models speaks volumes (pun!) of the shortcomings of the factory products.

Not many models live to see seven decades of improvements.

 

[Rmar]

As always, I am copying/pasting from my website directly here. Therefore, some tables, pictures, paragraphs may look odd here. If you want to read the review from my site here is the link:
https://www.erinsaudiocorner.com/loudspeakers/klipsch_heresy_iv/

Link to YouTube review:

Klipsch Heresy IV Speaker Review

• Wednesday, Nov 25, 2020

View attachment 95822
Intro
The Klipsch Heresy IV is a 3-way speaker with a classic look. The Heresy IV features a 12-inch midwoofer, K-702 midrange compression driver, and K-704 Tractrix horn for high frequencies. On the back of the speaker is Klipsch’s new element to this speaker lineup: the Klipsch Tractrix port. This speaker can be bi-amped if desired thanks to the links on the two sets of terminals above the rear port. The Heresy IV comes in a variety of finishes and features a tweed grille to hide the drive units. The particular model I tested is the Cherry finish. Current retail for a pair is $3,000 USD.



I won’t get in to all the details of the speaker’s makeup as that can be found on the specification page here, or in the provided screenshot below. I would rather spend my time in this review discussing the performance.

View attachment 95824
BUT! I will provide some of my own photos…


View attachment 95825


View attachment 95827


View attachment 95828

View attachment 95829

Tweeter close-up:

View attachment 95830


Midrange close-up:

View attachment 95831



Speaker terminals:
View attachment 95832

Grille with the Klpsch Heresy logo:
View attachment 95826

Aesthetics are always a very personal thing. Some may not like the look of this speaker, but I do. I also fancy a lot of other designs that are more flashy. This speaker is the opposite of flashy, though, yet I still appreciate its retro aesthetic.

Objective Data
Unless otherwise noted, all the data below was captured using Klippel Distortion Analyzer 2 and Klippel modules (TRF, DIS, LPM, ISC to name a few). Most of the data was exported to a text file and then graphed using my own MATLAB scripts in order to present the data in a specific way I prefer. However, some is given using Klippel’s graphing.
Foreword: Subjective Analysis vs Objective Data (click for more)




Impedance Phase and Magnitude:
Impedance measurements are provided both at 0.10 volts RMS and 2.83 volts RMS. The low-level voltage version is standard because it ensures the speaker/driver is in linear operating range. The higher voltage is to see what happens when the output voltage is increased to the 2.83vRMS speaker sensitivity test.
View attachment 95833


View attachment 95834


Frequency Response:

Notes about measurements (click for info)
The measurement below provides the frequency response at the reference measurement axis - also known as the 0-degree axis or “on axis” plane - in this measurement condition was situated at the tweeter. I did reach out to Klipsch directly - both via email and twitter - to ask what the designed reference axis was but received no reply. Per my research it seems everyone listens to these speakers on the tweeter axis (typical) so I proceeded with my measurements in that fashion.

The speaker was measured without the grille in place. I did not have the time to measure with the grille in place.
View attachment 95835

Below are both the horizontal and vertical response over a limited window (90° horizontal, ±40° vertical). I have provided a “normalized” set of data as well. The normalization simply means that I took the difference of the on-axis response and compared the other axes’ measurements to the on-axis response which gives the viewer a good idea of the speaker performance, relative to the on-axis response, as you move off-axis.

View attachment 95837


View attachment 95838

View attachment 95839

As I said above, the provided frequency response graphs were given with a limited set of data. I measured the response of the speaker’s vertical and horizontal axis in 10-degree steps over 360-degrees. Nearly 70 measurements in total are represented in my data. As you can imagine, providing all those data points in a single FR-type graphic below is a bit overwhelming and confusing for the viewer. A spectrogram is an alternate way to view this full set of data. This takes a 360-degree set of data and “collapses” it down to a rectangular representation of the various angles’ SPL. I have provided two sets of data: one set for horizontal and one for vertical. Each set consists of 2 graphics:

1. Full response (20Hz - 20kHz with the angles from 0° to ±180°) with absolute SPL values
2. Full, “normalized” response (20Hz - 20kHz with the angles from 0° to ±180°) with SPL values relative to the 0-degree axis

Normalized plots make it easier to compare how the speaker’s off-axis response behaves relative to the on-axis response curve.



View attachment 95841


View attachment 95842


View attachment 95843


View attachment 95844

The above spectrograms are the standard way of providing directivity graphics by most reviewers. Some prefer not to normalize the data. Some prefer to normalize the data. Either way, it’s a useful visual to get an idea of the directivity characteristics of a speaker or driver.
However, these “collapsed” representations of the sound field are not very intuitively viewed. At least not to me. So, I came up with a different way to view the speaker’s horizontal and vertical sound field by providing it across a 360° range in a globe plot below. I have provided both an absolute SPL version as well as a normalized version of both the horizontal and vertical sound fields.
Note the legend provided in the top left of each image which helps you understand speaker orientation provided in my global plots below.

View attachment 95845


View attachment 95846


View attachment 95847


View attachment 95848

Welp, I was interested in them for the aesthetic if nothing more, but there goes that idea.

CEA-2034 (aka: Spinorama):
The following set of data is populated via 360-degree, 10° stepped, “spins” from vertical and horizontal planes resulting in 70 unique measurements. Thus, this is sometimes referred to as “Spinorama” data. Audioholics has a great writeup on what these data mean (link here) and there is no sense in me trying to re-invent the wheel so I will reference you to them for further discussion. However, I will explain these curves lightly and provide my own spin on what they mean (pun totally intended). Sausalito Audio also has a good write-up on these curves here. Furthermore, you can find discussion in Dr. Floyd Toole’s book “Sound Reproduction”. Here is a great video of Dr. Toole discussing the use of measurements to quantify in-room performance.

In short, the CEA-2034 graphic below takes all the response measurements (horizontal and vertical) and applies weighting and averaging to sub-sets and can help provide an (accurate) prediction of the response in a typical room. If there is a single set of data to use in your purchase decision, this is probably it.
Alternatively, click this arrow, if you want my quick take on what these curves mean without going to another site.


View attachment 95849

Below is a breakout of the typical room’s Early Reflections contributors (floor bounce, ceiling, rear wall, front wall and side wall reflections). From this you can determine how much absorption you need and where to place it to help remedy strong dips from the reflection(s). In this case, the listening room would benefit from having at least a carpeted floor and, if willing to do so, acoustic absorption on the ceiling between the listener and the speakers.
View attachment 95850

And below is the Predicted In-Room response compared to a general target curve equaling -1dB/octave.

View attachment 95851
You may ask just how useful the above prediction is. Well, I’d be remiss for not delving in to that a little bit here. Please see my Analysis section below for discussion on this.


Harmonic Distortion:
Measurements were conducted at 2 meters ground plane using Klippel’s TRF module. Multiple output levels were tested to provide the trend of distortion component profiles and to provide a comparison against other drive units I have tested. The SPL provided is relative to 1 meter distance, averaged in the noted bandpass region.

View attachment 95852




Maximum Long Term SPL:
The below data provides the metrics for how Maximum Long Term SPL is determined. This measurement follows the IEC 60268-21 Long Term SPL protocol, per Klippel’s template, as such:

• Rated maximum sound pressure according IEC 60268-21 §18.4
• Using broadband multi-tone stimulus according §8.4
• Stimulus time = 60 s Excitation time + Preloops according §18.4.1

Each voltage test is 1 minute long (hence, the “Long Term” nomenclature).
The thresholds to determine the maximum SPL are:

• -20dB Distortion relative to the fundamental
• -3dB compression relative to the reference (1V) measurement

When the speaker has reached either or both of the above thresholds, the test is terminated and the SPL of the last test is the maximum SPL. In the below results I provide the summarized table as well as the data showing how/why this SPL was deemed to be the maximum.
This measurement is conducted once with a 20Hz to 20kHz multitone stimulus.
You can watch a demonstration of this testing via my YouTube channel:

Test 1: 20Hz to 20kHz
Multitone compression testing. The red line shows the final measurement where either distortion and/or compression failed. The voltage just before this is used to help determine the maximum SPL.

View attachment 95853
Multitone distortion testing. The dashed blue line represents the -20dB (10% distortion) threshold for failure. The dashed red line is for reference and shows the 1% distortion mark (but has no bearing on pass/fail). The green line shows the final measurement where either distortion and/or compression failed. The voltage just before this is used to help determine the maximum SPL.

View attachment 95854





The above data can be summed up by:

• Max SPL for 20Hz to 20kHz is approximately 110dB @ 1 meter. The compression threshold was exceeded above this SPL.

 

[Rmar]

1. Hoffman's Iron Law. (Anton Hoffman having been the "H" in KLH)bt
2. There's no replacement for displacement.

It is fricking trivial to build a high-sensitivity loudspeaker with very limited bandwidth and poor performance. It's not even hard to build one that's very efficient (i.e., skip the high-level crossover and go "fullrange"). I can do it in a half-hour with any of two dozen* "fullrange" drivers in the basement and a box. Such contrivances can be fun, but they're not hifi.

It's not difficult even to build a multi-way loudspeaker system that'll scream up a storm within limited bandwidth and with compromised performance.
That's pretty much what the Heresy is -- or at was in its first two, if not three, iterations. It's a shrunken Cornwall and it sounds the part. I have no doubt that the fourth generation Heresy is better. I don't think it could be worse without actively trying to make it worse.

The heritage Klipsch get bashed because they're bright, harsh, aggressive sounding loudspeakers. The K-horn was OK, and actually the Cornwall does a pretty good job of sensitivity, dynamics, and LF extension -- but the proliferation of mods and improvements for the heritage Klipsch models speaks volumes (pun!) of the shortcomings of the factory products.

EDIT: In fairness, Altec was their own worst enemy when it came to crossover design and implementation.
... but boy howdy did they make some fine drivers and horns.

_________________
* Probably more than two dozen.

Most people are not setting their Heresy IV's them up correctly if they are harsh. With these bright horns, you have to have your listening position just south of the intersection of the left and right speakers. If, like most folks tend to do, you sit right in the cross-hairs, they will be harsh. Move your chair back 2 feet and you will have found nirvana.

 

[Rmar]

With horns, placement may be different that what many folks are used to with conventional drivers. For starters, put them as close as you can to either the corners, or to the side walls leaving about 12". This next part is even more critical. Place you primary listening position at about two (2) foot behind the axis. Or conversely, if you can't move your chair, then toe the Heresey IV's in some more until the axis is 2 foot in front of you. In the manual it says to "angle speakers towards the listener" and then "experient" with the guidelines. The diagram in the book is wrong, or you could say it is the "pre-experient" position. Experienced Heresy owners know that the book is not correct.No one would have their horn speakers aiming right at the ears. That's tantamount to holding a fog horn to your head and blasting it. Move your chair back from the axis and you will open up an entirely new Heresy IV experience for yourself. It will be the experience that you have heard about and the reason why this speaker has sold strong for five decades. You will know why people use words like "Amazing, huge sound stage, holographic, stunning..." and on and on. You knew there had to be some reason folks loved them!

It is unfortunate this young fellow spent all that time doing his charts and graphs with a set up that was sub-optimal. It is also too bad for Klipsch, because when people pass off "science" as gospel, and when that "science" is based on the wrong assumptions or the wrong test set-up, it misleads others. All trained scientists know that before they start testing, they are required to "review the literature," to find out what others know, before they jump to hypothesis making or testing. Finding out what others know about the Heresy seems to have been missed in this case.

Lastly, if newcomers to the Heresy IV are interested, there is another tip they may be interested in. And that is to wrap Dynamat around the squawker. The squaker is the middle speaker. That will make a wonderful speaker even better.

 

[Sal1950]

It is unfortunate this young fellow spent all that time doing his charts and graphs with a set up that was sub-optimal. It is also too bad for Klipsch, because when people pass off "science" as gospel, and when that "science" is based on the wrong assumptions or the wrong test set-up, it misleads others. All trained scientists know that before they start testing, they are required to "review the literature," to find out what others know, before they jump to hypothesis making or testing.

I can appreciate your support of the Heresy's, like many speakers they have some strong points and some
weak points. As a 32y owner of La Scala's I'm intimately aware of most of them.
I'll agree the last thing you want to do is listen directly on axis and I also found the best setup for imaging to be crossing
over a bit in front of the listeners head.
That said, your criticism of Erin's review and measurements is quite in error. His measurements using the Klippel system
do reveal everything the Heresy is capable of both on and off axis. The fact is that all the speakers in the Heritage line have
very bad irregularities in frequency response no matter how you position them that could only be very slightly moderated by set-up.
A possible better approach might be to use a good DRC system to smooth the response a bit.

 

[mhardy6647]

 

[Sal1950]

What are the large square boxes in front with the small monitors sitting on top, Altec's?

 

[mhardy6647]

Yes, Santiagos.
They have very little cred with the Altecistas, but they sound pretty good to me. For a variety of reasons, I kept them instead of the Valencias I had, in fact.
That said, their primary use nowadays is as speaker stands.

 

[Sal1950]

Yes, Santiagos.
They have very little cred with the Altecistas, but they sound pretty good to me. For a variety of reasons, I kept them instead of the Valencias I had, in fact.

Very kool. thanks for the response.
Every time I see you post a photo of your room I turn green with jealousy.
What a perfect frickin space to set-up and tune a Hi-Fi plus extras!
Enjoy

 

[Rmar]

I can appreciate your support of the Heresy's, like many speakers they have some strong points and some
weak points. As a 32y owner of La Scala's I'm intimately aware of most of them.
I'll agree the last thing you want to do is listen directly on axis and I also found the best setup for imaging to be crossing
over a bit in front of the listeners head.
That said, your criticism of Erin's review and measurements is quite in error. His measurements using the Klippel system
do reveal everything the Heresy is capable of both on and off axis. The fact is that all the speakers in the Heritage line have
very bad irregularities in frequency response no matter how you position them that could only be very slightly moderated by set-up.
A possible better approach might be to use a good DRC system to smooth the response a bit.

I can appreciate your support of the Heresy's, like many speakers they have some strong points and some
weak points. As a 32y owner of La Scala's I'm intimately aware of most of them.
I'll agree the last thing you want to do is listen directly on axis and I also found the best setup for imaging to be crossing
over a bit in front of the listeners head.
That said, your criticism of Erin's review and measurements is quite in error. His measurements using the Klippel system
do reveal everything the Heresy is capable of both on and off axis. The fact is that all the speakers in the Heritage line have
very bad irregularities in frequency response no matter how you position them that could only be very slightly moderated by set-up.
A possible better approach might be to use a good DRC system to smooth the response a bit.

I am defending science. Nothing else. This is "Audio Science Review." If present your work as science, then make sure it is and not a method to get folks to click your links for personal profit. That's not science, my friend. That said, your criticism of me is quiet in error.

 

[Angsty]

I can appreciate your support of the Heresy's, like many speakers they have some strong points and some
weak points. As a 32y owner of La Scala's I'm intimately aware of most of them.
I'll agree the last thing you want to do is listen directly on axis and I also found the best setup for imaging to be crossing
over a bit in front of the listeners head.
That said, your criticism of Erin's review and measurements is quite in error. His measurements using the Klippel system
do reveal everything the Heresy is capable of both on and off axis. The fact is that all the speakers in the Heritage line have
very bad irregularities in frequency response no matter how you position them that could only be very slightly moderated by set-up.
A possible better approach might be to use a good DRC system to smooth the response a bit.

I agree with @Sal1950 regarding the Heresy measurements. I’m unclear why @Rmar believes they are flawed.

 

[rynberg]

It is unfortunate this young fellow spent all that time doing his charts and graphs with a set up that was sub-optimal. It is also too bad for Klipsch, because when people pass off "science" as gospel, and when that "science" is based on the wrong assumptions or the wrong test set-up, it misleads others. All trained scientists know that before they start testing, they are required to "review the literature," to find out what others know, before they jump to hypothesis making or testing. Finding out what others know about the Heresy seems to have been missed in this case.

What a condescending and ignorant reply...you might want to start reading some audio reproduction science books while sitting in your glass house. Do you even know what a Klippel is?