Gramophone Dreams #71: Heretic AD614 loudspeaker Page 2

Setup
In my room, Heretic importer and Fidelis Audio principal Walter Swanbon set the AD614s on custom 12" Fidelis stands about 20" from the wall. In that position, they played big soundstage-wise but were a little lean through the midrange. After he left, I experimented by moving them first forward some, which made them leaner and brighter. So then I tried moving them backward, ending up with the two boxes no more than 6" from the wall behind.

Sitting on the Fidelis stands, the 614's tweeters were 27" from the floor. My normal listening position places my ears 33" to 36" above the floor.

Because all the photos on Heretic's website show their speakers sitting directly on the floor aimed straight ahead, I tried that position for a while. The sound was overtly rich and smooth, not boomy, and quite listenable. I put ¾" wood blocks under the front feet, which allowed me to aim the 614's tweeters directly at my nose. In the new configuration, the sound was more transparent, deep-spaced, and sharply focused than it was with the speakers aiming straight ahead. Fidelis's Swanbon tells me that Heretic is finalizing the design of matching wood stands that will deliver the type of sonics I experienced with the arrangement described above.

Listening with Elekit's new TU-8900
The AD614 is so far outside today's mainstream design and marketing paradigms that whenever I listened, I couldn't stop my left brain from scanning for all those terrible faults the knowers told me I should find. But all I discovered was a Santa's bag of new pleasures—pleasures not offered by my Falcon Gold Badges or any other box speaker in my collection.

The first new pleasure the Heretics delivered was reproducing Sinatra's Only the Lonely LP, in my studio, with touchable textures similar to but less intense than those I experienced in the demo at HiFi Loft. Consider, though, that at my house, the Heretics were playing Frank with just two or three single-ended 2A3-tube watts. How many narrow-baffle speakers can do that?

The second new pleasure was even more exciting: The AD614s displayed an oceans-wide, minutely drawn, evenly lit soundspace that felt natural and relaxed, not exaggerated or contrived. A few days before Christmas, I was listening to the Medieval Players playing a bagpipe and a little bowl-shaped drum called a naker, performing a Christmas song from the Moosburg Gradual of 1360 entitled "Anni Novi Novitas" (Cum infulatus et vestitus Presul intronisator), from their album Al Manere Minstrelsy (LP, Planet Life PLR 052). The experience was striking to the point of being hypnotic. I watched drumbeat transients bouncing off stone walls with identifiable trajectories. The bagpipes, nakers, and the stone walls felt physical and visible, and the music felt timeless and universal.

Playing Sigismondo d'India: Lamenti & sospiri (24/96 FLAC, Ricercar/Qobuz) with Cossor 2A3 tubes in the Elekit TU-8900, the way-back part of the soundspace was clearer than ever, vibrant, and micro-focused. In contrast with my long-term budget-reference 300B amp, the TU-8600, which uses high-nickel cores in its output transformers, Elekit's TU-8900 features amorphous core outputs, which I think tend to juice up the recorded sound in an overly spectacular fashion. When you're old and alone in the dark, "overtly spectacular" feels like kinky sex.

When I switched from 2A3s to Cossor WE300Bs, opera sounded larger, smoother, and more electrifying through the Heretics than through my Falcon Gold Badges, so I kept playing opera recordings—from Italy and Kentucky—and staring at the AD614's treble. All I saw were beautifully textured, minutely articulated soprano harmonics.

With the WE300Bs, the Heretics' upper octaves sounded creamy, extra-dynamic, and clear. The 614's treble sounded uncompressed, wide open, and low-distortion, making sopranos, trumpets, and the upper octaves of the piano sound more intense than they did through my tiny Falcons or DeVore Fidelity's broad-baffled Orangutan O/93 floorstanders.

With the Elekit amp, the Heretics sounded more vivid and high-energy than the easygoing, rich-toned DeVore speakers. On the other hand, the comparison led me to notice how the O/93s played consistently quieter, with a more laid-back energy, most likely the result of a soft-dome tweeter, contrasting the Heretics' compression-driver horn.

The AD614s showed me how much my Falcons' compression was limiting my enjoyment of several of the world's louder, funner, and less intimate music genres. Most especially ska, dub, and reggae: genres for which large woofers on broad baffles are necessary to get out the message. With the Heretics, Scotty and Lorna Bennett's "Skank In Bed" from This Is Reggae Music Vol. 2 (1975 Island Records LP ILPS 9327) sounded more like I am sure it was intended to sound than it has sounded here since I gave my Altec 604Es to Art Dudley.

I used only three amplifiers for this report, and I ended up amazed by how the Heretics' amp-friendly load allowed each amplifier to sound more awake and vigorous than it usually does driving other speakers.

With the Parasound A 21+
I doubt any amp-swapping on any speaker could render a more dramatic change in sonics than exchanging the 3-watt 2A3 tubed Elekit TU-8900 for Parasound's 300W Halo A 21+ amplifier. The 21+ injected steroids into the AD614's monitor-like clarity. Every tiny bit of sonic data seemed perfectly clear and fully charged.

When I played my beloved Skip James LP, Devil Got My Woman (Vangard VSD-79273), my first thought was "Wow! I've got to tell J.C. how much this series-crossovered speaker likes solid state amps." The Heretics really lit up with Parasound's mighty class-A/AB watts. Skip and his guitar and piano never sounded more present or exposed by the microphone.

I doubt the AD614s ever dragged more than a few watts out of the Parasound, but the watts they pulled were smart, good-looking watts. The sound I experienced was probably the result of the A 21+'s heavy transformer and high-current power supply effortlessly streaming tiny details into the Heretic's resistive load.

Keep in mind that, throughout these Heretic auditions, I was listening constantly for those faults the knowers told me I would find. You know the ones: bloat, boom, uneven frequency response, and diffuse, unfocused imaging. But I didn't hear those faults. The A 21+ amp driving the AD614 speakers played dense, difficult-to-play piano and violin concertos with better-sorted, more tightly rendered, quicker-moving bass than any of my other speakers. The Parasound emphasized the Heretics' propensity for sharply focused details and rhythmic drive.

With the First Watt SIT-3
The first thing I noticed when I switched from the John Curl–designed Parasound A 21+ to the Nelson Pass–designed First Watt SIT-3 was the huge reduction in gain, from 29dB with the Parasound to only 11.5dB with the SIT-3. The thing I didn't notice, at all, was the reduction in potential output power, from 300W (into 8 ohms) to 18W. What I noticed most was the SIT-3's denser, more colorful and relaxed presentation, which I attribute to the absence of feedback in the First Watt amp. Beyond that, the sonic differences were subtle, with the A 21+ winning the Leica-focused deep-imaging contest and the SIT-3 taking gold medals for Best Tone and Longest Reverb Tail. Powering the Heretics, both amps showcased free-swinging dynamics and Webb Telescope vividosity.

Most importantly, the Heretics proved they could play comfortably and enjoyably with a wide range of amplifier types. That's rare.

Dear Reader,
That day at Sound by Singer, I was alienated by the disembodied clarity of those early Audio Physic speakers.

As I stared between those thin towers, my attention wandered. I looked around distractedly, noticing how everything in the room—including my chair—had been arranged for no other purpose than to facilitate what I felt was an excessively cerebral form of man-machine interaction. All feng shui lines pointed at that lonely Le Corbusier chair. No sofa, no scantily clad lovers, no pets, no cluttered coffee table.

My taste in listening environs leans toward plush, Bohemian-style couches with silk-embroidered pillows, candles, colored lights, and various forms of temple incense. Heretics feel at home in that environment.

There's another side of me that seeks pro-quality studio monitor sound, something I'd feel confident mastering a recording on. The Heretics scratch that itch, too. And then there's the Jazz Kissa and hip coffeeshops with speakers hanging from the ceiling. I suspect the Heretics would feel right at home.

One last point
As much as these speakers look like vintage Altecs, they do not sound like vintage Altecs. Compared to the various Altecs I've owned, or to Alex Halberstadt's Valencias, which used to belong to Art Dudley, the AD614 is dramatically smoother, more precisely focused, and more evenly balanced across its bandwidth. Art thought speaker imaging was overrated, but I loudly disagreed. For me, if tone, texture, and tempo are properly recovered, then vivid imaging is added proof that a majority of small-signal info is getting through.

In my room, with my sources and amplification, the broad-chested Heretics project the widest, most intricately focused and evenly lit soundspace I have encountered, and they did it while sitting only inches from the wall.

The Heretic AD614s played larger, louder, and more electrifying than my Falcons, Magnepans, or DeVores. They sounded more like studio monitors than Harbeth's 30.2 speakers. But I doubt they sound much like any contemporary speakers you are familiar with. I could always hear the paper in the Heretics' cones, and I was never not aware of the location, mass, and volume of their thin-walled boxes. But for me, those things were more of a comfort than a distraction.

You know how I'm always saying that I can't find what I'm not looking for. Well, the Heretic AD614 seems to be the kind of loudspeaker I've been searching for.

It works well with all types of amplifiers, suits my taste in sound, and is sized perfectly for my room. I am happy I discovered them.

Give them a listen. These Heretics might be the speakers you've been wishing for, too.

ARTICLE CONTENTS

COMMENTS
JRT's picture

Herb Reichert mentioned the use of 2nd order Linkwitz-Riley passive series crossovers.

Linkwitz-Riley refers to the late greats Siegfried Linkwitz and Russ Riley. You might find interesting some of Siegfried Linkwitz's commentary on the subject of passive and active crossovers, quoted excerpts below, with more available on the associated webpage from his website (links further below), which is a treasure trove of excellent information centered on the applied science and art of loudspeaker design, with much surrounding information.

"Crossovers may be implemented either as passive RLC networks, as active filters with operational amplifier circuits or with DSP engines and software. The only excuse for passive crossovers is their low cost. Their behavior changes with the signal level dependent dynamics of the drivers. They block the power amplifier from taking maximum control over the voice coil motion. They are a waste of time, if accuracy of reproduction is the goal."

"I have a strong preference for line level active dividing networks ahead of the power amplifiers. In this approach the power amplifier output is connected directly - except for a very low resistance speaker cable - to the voice coil of the driver. The amplifier takes maximum control over the motion of the speaker cone which gives a greater sense of clarity and dynamism compared to a passive dividing network between amplifier and driver. Active crossovers make much more effective use of amplifier power. A clipping woofer amplifier is not seen by the tweeter, which has its own amplifier. The clipping of the woofer amplifier may not even be noticed in this case. It would surely be heard with a passive crossover, where it might even overheat and damage the tweeter, because of the large amount of high frequency energy in the clipped signal."

"Crossover filters for a speaker usually incorporate frequency response corrections for the individual drivers to obtain a desired overall response. The active network has the advantage of correcting easily for different sensitivities of drivers and equalizing not only the individual drivers but the combined response as well. Not having to deal with the interaction between driver impedance and passive filter network gives the designer of an active crossover/equalizer much greater freedom and control to develop a superior product."

https://www.linkwitzlab.com/crossovers.htm

https://www.linkwitzlab.com/frontiers.htm

https://www.linkwitzlab.com

Jonti's picture

Fascinating stuff as always, Herb. I recently picked up a pair of Altec 614D enclosures housing archaic 600B 12-inch full-range drivers. The "puzzling ductless vent, with no 'tube' to tune the port" that Gaboury describes is there on the 614D too, and left me equally mystified, but I like the broad-spectrum effect it has on the tunefulness of the bass. The really surprising thing for me is how well-defined the lower frequencies are coming through such a port. Vastly superior, to my ear, to the arm's-length cylindrical tubes used in Tannoy Arden ports, for example.

Having placed the Altecs a fair distance away from the back wall by instinct, I'm now going to try pushing them closer to see if there's any audible benefit in doing so.

Ortofan's picture

... he could live happily ever after with a pair of Spendor BC1 speakers?

If that was the case, why, then, is the "bunker" not home to one or the other iteration of the Harbeth SHL5plus - or, for that matter, the Graham LS8/1 or the Stirling Broadcast LS3/6?

However, if he has since developed an affinity for speakers with coaxial drivers and paper cones, then he really ought to do a follow-up review of the MoFi SourcePoint 10.

Lastly, it should be noted that, toward the end of his career, the late Bud Fried was a proponent of series crossover networks.

Simon from Oz's picture

Sorry Herb, that chair is not a Le Corbusier piece. It was designed by Marcel Breuer in 1925, often called a Wassily Chair as he also made one for the artist Kandinsky.

Le Corbusier did some beautiful sofa and chair designs, but that's not one of them.

thethanimal's picture

Simon, I initially thought that was a mistake too, but realized the Le Corbusier chair was at his Sound by Singer demo of Audio Physic speakers some time ago, while the lead picture is from a Heretic demo at HiFi Loft. Different salons, different times, different chairs, but good taste all around.

Simon from Oz's picture

Ah ok, I should pay attention more. Thought it was a glaring error, bit like saying that First Watt amp was a Dan D'Agostino design...

tenorman's picture

Such a lovely and well deserved tribute by Heretic speakers of Montreal to Art Dudley . Incorporating Art’s initials into the name of their speakers was a very kind gesture .

Beautifully wrriten review Herb - thank you . I particularly enjoyed ( and chuckled at ) your wonderful “ Webb Telescope vividosity” descriptive . A classic Herb-ism if there ever was one .Doesn’t get better then that . Unfortunately, the Heretic’s are more than a little out of my price range . Thankfully I have my beloved Falcon Ls35a Gold Badges which regularly bring me joy .

Herb Reichert's picture

I am pleased you enjoyed it and honored by your observations.

Art Dudley's stories made us all better Listeners.

herb

Long-time listener's picture

"I could always hear the paper in the Heretics' cones, and I was never not aware of the location, mass, and volume of their thin-walled boxes."

Those sound like problems with tonality. Is that not a problem?

I once heard those Audiophysic speakers you spoke of -- I assume it was the same one -- and the memory has stayed with me for decades. I've always regretted not buying them. Surprised to hear them spoken of so disparagingly.

Trevor_Bartram's picture

The use of large diameter cone coaxial driver on a large baffle is a way of mitigating baffle step compensation and edge diffraction. The large cone acts as a horn to control directionality at high frequencies where diffraction in a small driver is problematic. However the large cone is moving and causes doppler distortion at high frequencies. I'm unsure if Doppler distortion is audible but it should be measurable. Heretic should submit their speakers to a Stereophile review!

Trevor_Bartram's picture

Herb, with a 12" paper cone operating to 1.7KHz, did you hear any cone breakup? Any coarseness to vocals? There are good reasons why various alternate cone materials (bextrene, polypropylene, metal etc) have been tried over the years. Some upper midrange coarseness has even been noted in Buchardt's earlier 6" paper cone designs.

Mr.Taylor.Calculus's picture

Thanks, Herb.

As always, I greatly enjoyed your column. I was, however, looking forward to hearing how it worked with your LTA Z10e integrated. Did you have any comments about that combination?

Herb Reichert's picture

I still have not hooked up the LTA Z10e to the Heretecs.

My only excuses are sloth and the Z10e is in my desktop system so I can listen to electrostatic headphones all day.

but I can't imagine how it would not work with the Heretecs

when I finally try it I will report back

herb

RH's picture

Herb,

Excellent review! I find you often get at the gist of sonic characteristics you are seeking, and convey them well to the reader.
For instance in your older review of the Joseph Audio Pulsar speakers, you nailed the difference from the Harbeth speakers - "the extra flesh and density" in the Harbeth sound. My experience with owning both Harbeth and Joseph Audio speakers (currently the Perspectives) concur.

Like you I enjoy sonic density, flesh and blood, to the sound of a speaker. So the Devore O series speakers have been a favorite of mine for those qualities. But they were too wide and presented some ergonomic problems for my smallish room which a much narrower speaker - the Joseph Audio Perspectives - solved for me. Plus I adore the purity of tone and imaging in the Joseph speakers.

My big "discovery" was adding a smallish curved diffusor behind and between my Joseph speakers. This added a big dollop of image density and aliveness! Now sonic images of a voice, a drum kit, a sax etc just seem "there" - palpable and solid. As close to the best of both worlds - the mammoth soundstaging and imaging prowess and purity of the Joseph sound, with that added density - that I've managed to achieve thus far.

I'd love to hear these Heretic speakers (though their form factor wouldn't work for my room).

thethanimal's picture

Herb, I imagine you’ve auditioned the OJAS bookshelf speakers with the coaxial driver. It seems the two are cut from the same cloth; I’d be interested in your thoughts. Maybe an upcoming Gramophone Dreams?

Herb Reichert's picture

the OJAS bookshelf speaker.

But I suspect the secret of this speaker's success, what separates it from the co-axial cohort, is the series crossover.

hr

X