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Audio Science Review of Heresy IV


PrestonTom
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Over at Audio Science Review there is a review (mostly measurements) of the Heresy IV

 

Note: This is not done by their regular reviewer and I can not speak regarding the competence of the measures presented (they may or may not be accurate - I have no idea). 

The review is not favorable. This is just an FYI. If you don't like what you see, don't beat up on me (I have certainly never heard or measured this speaker). 

 

https://www.audiosciencereview.com/forum/index.php?threads/klipsch-heresy-iv-speaker-review.17853/

 

 

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I think you hit the jackpot, Tom. Lots of data there.  I've requested that he add phase and group delay plots.  Let's see if he'll do it.

 

Chris

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8 hours ago, PrestonTom said:

Over at Audio Science Review there is a review (mostly measurements) of the Heresy IV

 

Note: This is not done by their regular reviewer and I can not speak regarding the competence of the measures presented (they may or may not be accurate - I have no idea). 

The review is not favorable. This is just an FYI. If you don't like what you see, don't beat up on me (I have certainly never heard or measured this speaker). 

 

https://www.audiosciencereview.com/forum/index.php?threads/klipsch-heresy-iv-speaker-review.17853/

 

 

 

As a group of people, they're piling on in a big old session of "we've all missed the point".

Smart people being dumb 🤣

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I am not educated enough to comment regarding the measurements and technical data, but I have one experience related to his reviews.

 

Not to long ago I spotted a Revel M16 bookshelves on a discount at a local audio store. Reading all the rave reviews I thought why not audition them. So I went there, Revels were set up in a new very well sound treated audition room, and here we go... after a few familiar tracks it became very obvious that the speakers can go loud, they had the qualities described in available reviews. But more obvious was that the low end was very accentuated as well as highs (a bit less than the bass). But I was not impressed with the lack of details in the tracks familiar to my ears. So these were good speakers to my ears, but not good enough to bring them home with me.

 

And after a few days I read the audioscience review. I understand the praise for little Revels, but much more important was what I heard. And those elevated lows and highs and the lack of details in the music (may be mid-range, for which this speaker lacks the separate driver) were not to pleasing. And just to mention, the  measurements on audioscience review site confirmed that accentuation of lows and highs, but I could not believe that would be so obvious.

So, I can read all the measurements as a guide, but my ears will fill in the rest.

 

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On 11/26/2020 at 1:41 AM, parlophone1 said:

So, I can read all the measurements as a guide, but my ears will fill in the rest.

Presently, this is the problem with Amir's reviews at AudioScienceReview.com:  he measures (and posts) many measurements but seems to lack the expertise to interpret what he's got, instead offering a mishmash of what I'd call "off the wall" conclusions.  I don't believe that this situation is going to change soon...sort of like John Atkinson trying to convince himself and everyone else that accelerometers attached to the walls of the loudspeaker enclosures translates to genuinely useful information.  (It doesn't.)

 

But the Heresy IV measurement thread there was not performed by Amir, but by a different person--who also happens to be an engineer, and who lives in/near Huntsville, Alabama (Redstone Arsenal, ARL, et al.).  This other guy seems to have a little better handle on what the measurements mean in terms of subjective sound qualities, but he is still a self-confessed novice who's learning.

 

So what is the value of these loudspeaker measurements?  Assuming the data was taken correctly (and I think it mostly was, with a few notable issues), the data IS useful, but unfortunately, the reader must be able to understand the meaning of that data for themselves.  This is what I have found with Amir's measurements and the guy from Huntsville (Erin, I believe is his name) is basically no different.  My advice from the measurements is to read what you will, but don't worry too much about the author's "bottom line" or his conclusions.  Let the measurements be a way of calibrating your own ears to the subjective experience of hearing the loudspeakers in real life (if you can--which is currently a problem for Klipsch Heritage, and for any loudspeaker at all due to SARS-CoV-II virus safety issues).

 

Did I get something from the measurements?  Yes, but maybe it is much less than the author at AudioScienceReview.com seems to think it means.  I get to calibrate my ears a bit more to the Heresy I's in my garage in terms of the performance of the basic configuration/design.  The drivers and horns are different, and the box has no port (something that I have to disagree with in the H-IV design as less attractive than using, say, a DSP crossover instead of the passive networks, and simply adding a little boost on the low end that doesn't suffer from increased phase and group delay growth that bass reflex designs will have relative to acoustic suspension designs), but the basic configuration and its pros/cons are still there.

 

Why do these type of measurement threads garner so much attention?  Perhaps it's because they are filling a void in many consumers' needs: that of having good data, sort of like what Consumer Reports does for a living (but hopefully much more usefully than CU's old loudspeaker reviews, which were basically trash).  This should be a message to hi-fi equipment manufacturers.  If they got out in front of this type of "DIY measurement forums" and published the results that they themselves have on their products, they would have the chance to mold public opinion of the performance of their equipment much more effectively, rather than publishing inaccurate and almost no data at all.  Just like CU's reviews, these DIY measurement forums help to keep the manufacturers a bit more honest.

 

Chris

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3 hours ago, Chris A said:

(something that I have to disagree with in the H-IV design as less attractive than using, say, a DSP crossover instead of the passive networks, and simply adding a little boost on the low end that doesn't suffer from increased phase and group delay growth that bass reflex designs will have relative to acoustic suspension designs)

 

Fast Bass

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Thanks for that thread on "fast bass", Greg.  This is precisely the point, the group delay of bass reflex is a direct indicator of the phase lag/group delay of the bass bin.  As we have discussed privately, this is important stuff for the perceived performance of the bass, and one that I've had made painfully aware of in my music demastering efforts.  After I flattened the phase on the surrounding 5.1 loudspeakers in my setup as much as I could using the typical filters found in DSP crossovers (IIR), I applied Dirac through the AVP upstream of the crossover, which brought with it FIR filter capability, which further flattened the bass frequency phase growth a little bit.  I've had to go back and demaster the tracks that I had in my FLAC library (about 15K of them) one by one because they now have too much bass response in them. 

 

More on this subject here (click on the first line of the header of the quote below to take you to the exact post of interest):

Now all of this is completely invisible to the folks over at AudioScienceReview.com.  Pretty much without exception, all of them own and champion direct-radiating loudspeakers (not like the hybrid horn-loaded + woofer loudspeakers like the Heresy or Cornwall, or fully horn loaded like the La Scala, Khorn, and Jubilee) having much higher modulation distortion, in addition to lousy directivity control (something measured on that forum thread on the Heresy IV...but no one discussed its effects), and terrible phase response.  These are big deals in my experience, but they will not see it and refuse to acknowledge its auditory effects. 

 

The Heresy IV SPL response is easily corrected via upstream DSP (and is quite effective) for those that value a more neutral presentation, which is the major negative point the author made in his "bottom line" arguments.  But there is nothing that I could say that would dissuade those that believe in the "flat SPL response without DSP" crowd that the trade for the Heresy IV is a much better one.  This is but the tip of the iceberg of the differences between them and Klipsch.

 

Chris

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37 minutes ago, Chris A said:

But there is nothing that I could say that would dissuade those that believe in the "flat SPL response without DSP" crowd that the trade for the Heresy IV is a much better one. 

 

I used to be among that crowd, devoting almost religious significance to the "straight wire with gain" philosophy. That was fine, back in the days when Watts were precious and one tried to get as much out of one Watt as one could. But nowadays Watts are cheap, and so is computational power. And as I have experimented with some of the techniques that my signal processing background provides me, I have found that the results can be extraordinary.

 

For example, just by measuring the impedance of a woofer in and out of its enclosure, I can derive its transfer function -- a mathematical description of its frequency and time responses. Furthermore, with just some algebra and DSP arithmetic, I can turn even a bad woofer alignment into a good one (within some well-defined constraints dictated by physics). The only costs for all of this are an increase in power drawn from the amplifier and the attendant increase in woofer excursion at the lowest frequencies -- there's no such thing as a free lunch.

 

As powered loudspeakers with DSP capabilities become more common, I believe that this will become the rule rather than the exception. And, as with all good things, there will be some who abuse the capabilities, with the resulting general backlash against it. But in the cases where it is applied judiciously, expect great things.

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Don’t Heresy IVs come with instructions to locate them in a corner, or at least near a wall?  Placing them out in the middle of the room like that might make for consistent measurements among speakers, but Klipsch Heritage speakers are not exactly like most other speakers, and should be located as they were intended, in order to let them perform as designed.  That may be why that review seems so much at odds with every other review.

 

Also, that was a ridiculous number of measurements.  What was the point of measuring the woofer (or “mid-woofer”, as he seemed to prefer) out of the cabinet?  It tells the reader little or nothing about how the driver will perform in a specific cabinet.  Maybe there is a tiny niche group that want all that info, whether it’s useful or meaningful to them, so it’s good that he’s there for them.  I can’t see myself ever reading another review on AudioScience Review.

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6 minutes ago, Islander said:

I can’t see myself ever reading another review on AudioScience Review.

 

That's how I felt after the first review I read on that site. Even more so now that I've read this one on the Heresy IV.

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One of the areas that I was most interested in is the horizontal and vertical polar coverage responses of the Heresy midrange horn (nominally 700-5000 Hz, below).  First the horizontal polar sonogram (normalized to on-axis SPL):

 

klipsch-heresy-iv_horizontal_spectrogram

 

Pretty good -- much better than I would have expected (it has straight-sided horn walls with a truncated tractrix mouth roll out):  dsc07169-jpg.95831

 

This is different than the exponential Heresy horns that I own (1981 models).  There is a disturbance at the midrange-tweeter interference band (about 4-8 kHz) also.

 

Now let's look at the vertical polar sonogram:

 

klipsch-heresy-iv_vertical_spectrogram__

 

A bit less nice than the horizontal.  This is a consequence of its small vertical mouth dimension of the midrange horn (which is dictated by the small size of the Heresy itself using separate horns for each of the tweeter and midrange--more on that later), which allows the vertical polars to start to spill out on the ceiling and floor starting just above 2 kHz, and continuing down the the crossover frequency with the woofer (850 Hz)--down to about and octave below that point (425 Hz), with an interesting void in the downward polars between 800-1000 Hz. 

 

This says to me that the Heresy IV needs to be sitting on a fairly good pad of absorption material in-room (probably about a 2 feet x 2 feet across in size) to moderate that downward lobe of vertical polars to more closely match the other direct energy coming from the midrange driver/horn.  In addition, there is a corresponding loss of vertical polar control in toward the ceiling.  It it were me, I'd probably find some absorption material to lay on top of the loudspeaker box and stick out in front of the front to absorb some of that energy headed toward the ceiling in the 1.2-2.4 kHz band.

 

There is also a spike of acoustic energy at about 6.6-6.8 kHz that a pad of absorption material that the loudspeaker is sitting on could absorb , plus a little absorption sticking out on top would help to moderate.  These are cheap and easy in-room acoustic treatments that would likely be very effective.  I'd recommend using some material and listening for the differences, and move it about and/or add/subtract some the absorption pad area until is sound most neutral and natural with female vocals and the upper registers of piano, etc.

 

I think I'll apply those two ideas to the Heresy I's in my garage.  I have a stock of Auralex Sonofiber 2'x2'x1" squares that I can easily use for that duty.

 

Chris

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One of the ideas that has been documented has been the use of ESS AMT-1s on top of Cornwalls, La Scalas, and Belles (like my surround loudspeakers have presently).  This idea also looks like it might be useful to those running older Heresies and wanting to hear a more spacious soundstage in depth.  A couple of AMT-1s plus bi-amping with a DSP crossover (e.g.,a miniDSP 2x4 HD)---just like the AMT-1/Heritage "kit" thread would likely be an interesting and low cost experiment.  I'd recommend an 1800 Hz crossover point.

 

Wings Forward.jpg

 

A bit noisy horizontal polar spectrogram of a single AMT-1 in-room:

 

AMT-1 normalized polar plot (2D).jpg

 

Chris

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I like the ASR reviews because Amir is doing things no one else, certainly not Stereophile, is doing right now. He is using a consistent, defendable, set of metrics (no Klipschorns on stools in somebody's driveway) he is not using a lot of fluffy adjectives to puff up his advertisers'  products; and he can admit when he's made an error. His call-outs of  several examples of high priced trash audio products I am sure have made the manufacturers squirm. 

 

I do share one concern about Heritage that both Stereophile and Amir point out-cabinet resonances. In all the uproar about Sterophile's bungled review of the Klipschorns, I did not see any discussion of the midrange cabinet resonances discovered. One would think that Klipsch could engineer these resonances to be lower in frequency and amplitude that the reviews have uncovered.

 

Having said that I don't always agree with him or any other reviewer. His speaker reviews concentrate on bookshelf systems and has not tested many floor standers. His idea of perfect response is output declining with increasing frequency (like pink noise). I don't know why he thinks that is "perfect";  you'd have to ask him.

 

 

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1 hour ago, boom3 said:

Having said that I don't always agree with him or any other reviewer. His speaker reviews concentrate on bookshelf systems and has not tested many floor standers. His idea of perfect response is output declining with increasing frequency (like pink noise). I don't know why he thinks that is "perfect";  you'd have to ask him.

I believe I know why--the same reason why Toole I believe advocates it: direct radiating drivers splash a lot of energy around the room, and that means that a downward sloping response tends to compensate for the increased level of early reflections at higher frequencies that direct radiating loudspeakers typically have.  This is the "salt-and-pepper EQ" phenomenon that Roy has talked about with horns that begin to lose their directivity at lower frequencies.  This is not necessary with K-402s in my experience: you want flat response as measured at one metre microphone distance. 

 

An additional reason is that Toole knows that many/most recordings have accentuated highs during mastering between 1-5 kHz (just below the major sibilance frequencies, since many/most vocalists can't keep their mouths away from the microphones, another interesting subject, and therefore the mixing and mastering guys wind up having to cut somewhere in the 4-7 kHz band.  You can see this on many/most popular music recordings, i.e., the difference between the black line and the red line, below, from the John Peter Chapman 1996 JAES article:

 

361596603_Chapmancurve.thumb.GIF.c12d3c7d58b7fb10d17085f42e57ce17.GIF

 

 

Ave Dynamic Range by Genre.PNG

 

It's the genres that tend to the right side of the above average dynamic range (crest factor) that experience increased amounts of high frequency boost--and lower dynamic range.  The problem is, of course, that the highs above 10 kHz are doubly attenuated using the Toole downward sloping SPL response for loudspeakers. 

 

I think there's one other factor--I don't believe that all people are taking their measurements at one metre.  If you flatten the SPL response at one metre (easy to do with DSP), then back off to 3-5 metres with the microphone, you will get that down-sloping response automatically.  Most people that argue this point I believe are trying to measure loudspeaker response too far away in a noisy listening room full of early reflections if taken that far back.  This is also my gripe with "room correction software".  The major failing of these applications is that they are taking the measurements with the non-minimum-phase room reflections embedded in the measurements, and they typically do a lousy job of cutting those effects out of their measurements.

 

Unless you're outside on soft ground, I'd strongly advise taking your in-room measurements at one metre microphone distance with the microphone centered on midrange height, and aim for flat response.  Unless using half-space microphone measurement techniques with the microphone on the ground, in which case, the advice gets a lot more complicated, and you generally need more and better measurement applications and equipment.

 

Chris

 

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1 hour ago, terasankka said:

This review was not done by Amirn. 

 

Welcome!  New from the ASR forum?  Yes, this particular review was done by Erin instead of Amir.  He has a different measurement rig than Amir's NFS setup, and a slightly different perspective.  I hope that both of them start publishing phase and group delay data as a matter of course. 

 

Like I mentioned in the ASR forum, that's the other half of the transfer function, and as time passes I've found more and more that this data is almost as important as SPL response.  The group delay data posted in that ASR review thread (that I requested) doesn't look like it's terribly accurate yet, and the phase plot is still yet to be posted as of this writing.  Perhaps I'll pitch in to his cause when he updates the group delay plot and adds a phase plot that's accurate.  Klippel gear is not inexpensive: $10K is about the starting point, and a full-up NFS setup that Amir uses is in the $60K--$100K [USD] range.  That's not chicken feed.  He must have a very well-paying job.

 

6 hours ago, boom3 said:

...Having said that I don't always agree with him or any other reviewer. His speaker reviews concentrate on bookshelf systems and has not tested many floor standers...

I don't expect that to change anytime soon.  Apparently a significant percentage of ASR membership puts most of their money into electronics and "small loudspeakers" (like your typical "audiophile forum").  😉  That's sort of the opposite of those here that own Klipsch Heritage loudspeakers larger than Heresies.  Different priorities, clearly.  I'd prefer hi-fi sound in-room myself. 

 

Chris

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I can’t claim to understand hardly any of the technical discussions as to why or why not the Heresy IV measurements made by Eric on ASR are relevant. But I do agree with Chris A. that Klipsch, and all other manufacturers, need to get out in front of the 3rd party measurement issue. Manufacturers need to start publishing the how and why of their measurements, and be prepared to defend their results. If not, I believe that eventually they will be punished in the marketplace. For a couple of hundred dollars people can purchase measurement tools that PWK couldn’t have dreamed would be available to be used (and abused) by the typical high end audio customer. And we all know how easy it is to disseminate the information, and disinformation, from it’s use. 

 

Secondly, I think manufacturers, especially Klipsch,  need to be far more specific as to how they intend for their speakers to be placed in the listening room. PWK was clear. In the corner. Even if it wasn’t a Klipschorn. If that wasn’t available, as close to the corner as possible, at the wall/floor junction. And toed in 45 degrees. For example, I think Klipsch’s current recommendation of current Klipschorns with the enclosed backs being placed in the “proximity” of a corner is far too vague, and results in so called  measurement “experts” measuring the speakers on a dolly in the driveway.  

 

In my opinion, it should be clear to Heresy buyers, and reviewers, that Heresy’s are meant to be placed on the floor, in corners if possible, otherwise at floor/wall junctions if not, and toed in 45 degrees. Unless of course those recommendations have been changed. Then what the new recommendations are should be very specific.

 

To my non-technical mind, speakers should be measured in room, placed as they were designed to be placed, and not upside down in the driveway. But unless the manufacturer makes it clear how they measure, and how they want the speakers placed in the listeners room to achieve the best results, they have no real basis to argue against testing that shows their speakers in a negative light. 

 

 

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