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The Horn Shoppe Hornline

A Bass Augmenter for People Who Hate Sub-woofers

[Italian version]
[The Hornline]

Product: Hornline, Bass-Augmenter
Manufacturer: The Horn Shoppe
Price: $700 USD
Reviewer: Richard George - TNT USA
Reviewed: March, 2004

Subwoofer. The very term conjures images of lowered cars, pounding, single-note bass, and hip-hop with shaking walls and rattling windows. Or, perhaps visions of massive movie explosions or reverberating dinosaur footsteps come to mind. While subs have been warmly received by most consumers, they have earned a poor reputation among many music lovers for several reasons, one of which is the poor quality sound for which most are infamous.

Another compelling reason for the distrust of subwoofers has been the faulty implementation of subs by many mass-market speaker and sound-system manufacturers. They insist on combining small satellite speakers, which are incapable of reproducing frequencies below 200Hz or so, with a cheap subwoofer that is poorly equipped to deal with frequencies above 100Hz. While non-discriminating viewers of DVD movies may find the resultant sound quality acceptable, the effect of this type of speaker system on music can be dreadful.

Despite the negative reputation subwoofers have earned, many audiophiles have generally come to terms with the benefits of a high quality, musical sub. By retaining full-range speakers for mains and combining them with a high quality subwoofer, a much greater frequency range can be achieved adding depth and substance to the sound.

To this end, the question becomes: what defines a good subwoofer? The answer depends on what its proposed use is to be. For movies deep bass and floor-rumbling power seem to work best - similar characteristics seem to work well for rap and hip-hop - a flat frequency response is simply unnecessary. For other types of music, the sub needs to have a flat frequency response over its range, it must be able to reproduce bass notes and transients accurately without adversely affecting rhythm or timing, and it needs to integrate well with the main speakers.

Many people say there is no such thing as "fast bass", that, by the very nature of the frequencies involved, bass cannot be "fast". If discussing a pure tone, say 35Hz, that is a very true statement. However, bass transients require quick response from the driver, a property that conflicts with design parameters that allow foundation-rattling bass power. A sub with "fast bass" is merely one that responds quickly and accurately to transients.

Consumers can pay thousands of dollars for a subwoofer that meets these requirements, but as is often the case with audio equipment, good performance can be obtained for a more reasonable sum. Value is an important concept with subwoofers just as it is with other audio components. Most powered subwoofers are constructed along a conventional pattern - that is, they tend to be a cubic or elongated, ported box with a long throw, low-frequency driver that has a heavy cone designed for large amounts of power, and an integrated power amplifier that incorporates an adjustable crossover network.

Then there is the Hornline, which is about as unconventional as a subwoofer can be. The Hornline was designed by Ed Schilling of the Horn Shoppe. The Hornline, is not, according to Ed, a subwoofer but rather, it is a "bass-augmenter". Is there a difference?

What is the Hornline?

[The Hornline and Horn]

The Hornline is a powered, single-driver speaker tuned to deliver reasonably flat frequency response below about 80Hz. Having said that exhausts all similarities between the Hornline and conventional subs. The Hornline appears to be a larger version of the Horn Shoppe Horn, but with its own power amplifier. In fact, its name is a good description - the Hornline is a hybrid between a rear-loaded horn and a transmission line. Instead of short and squat, like a conventional sub, the Hornline has a tall, monolithic cabinet with a single 17cm (6.5 inch) driver centered high in the baffle.

The Hornline cabinet measures 27cm x 29 x 83cm (10.5 x 11.5 x 32.5 inches) and weighs about 16kg (36 pounds). The cabinet is made from hardwood plywood on the exterior surfaces, and MDF for the horn/TL folds. The cabinet top and sides are flat, smooth, and featureless. As with the Horn Shoppe Horns, the back of the cabinet forms a horn mouth. Looking upward into the mouth reveals fibrous stuffing. The exact shape, size, flare rates, and dimensions of the Hornline interior are closely guarded secrets known only to Ed and his father. However, Ed did reveal that the first third of the pipe past the compression chamber behind the driver has no flare at all - the first third is pure transmission line. The rest of the length is flared. Acoustic stuffing is used in only a portion of the pipe.

The Hornline has its own power amplifier, but unlike conventional subs, the amp is not built into the speaker cabinet - instead, it is in its own box connected to the Hornline with a pair of speaker cables. The binding posts are located on the back of the cabinet, in a cup near the top of the horn mouth. While not as eccentric a location as the top-mounted binding posts on the Horns, the location is more practical and more aesthetically pleasing.

[Vifa Driver]

Top of the Hornline baffle showing the Vifa driver.

The driver is a Vifa bass driver with a mineral-filled, polypropylene cone, 8-ohm impedance, and 70-watt maximum power handling. Being only 17cm (6 1/2") in diameter with a lightweight cone, implies quick transient response. Powering the driver is an inexpensive, 100-watt, subwoofer plate amplifier with integrated crossover, variable low-pass frequency setting, and a phase reversal switch. The amplifier, from Parts Express, has low-level and high-level inputs. Since the amplifier is built into its own box, which matches the finish and appearance of the Hornline, any suitable amp could be easily substituted. All listening evaluations were done with the standard amplifier.

How Does It Sound?

Fans of hip-hop and viewers of special effects laden movies want to feel low bass, not just hear it. They want it to rattle windows and shake walls - integration with main speakers usually isn't an issue. Most music lovers don't want to hear a separate subwoofer, they simply want their system's frequency response to cover as much of the audible range as possible without being able to distinguish separate sources for different portions of the spectrum.

To this end, the Hornline excels, given compatible main speakers and proper setup. With a properly set up system, the Hornline is indistinguishable from the main speakers, rendering it 'invisible'. Tuned to give flat output down to about 30Hz, the Hornline is not the last word in deep bass, but it will fill in the lower half-octave to octave below typical, full-range main speakers, and it will do so musically and unobtrusively.

Bass transients are quick and clean with rarely a trace of overhang - the notes begin as they should and end when they should without the muddy, jumbled, hollow booming so prevalent among mass-market subwoofers. Sustained bass notes, such as from a piano or contrabass, sound just as expected with accurately reproduced pitch and timbre. In addition to its sound qualities, excellent integration with many speakers is one of the Hornline's finest virtues.

[The Mouth of the Hornline]

It should be no surprise to discover the full-range speakers that integrated best with the Hornline were the Horn Shoppe Horns. Several configurations with the Horns were tried, but the most impressive for overall sound quality took place at a friend's house in a listening room much larger than my own. During an informal gathering of audio enthusiasts, the Horns were placed well out into the room with the Hornline placed against the back wall.

Absolutely seamless integration resulted in greatly improved frequency range (compared to the Horns alone), down to about 30Hz. The huge soundstage and pinpoint imaging of the Horns were not compromised in the least. More to the point, the beautifully musical presentation of the Horns was not impaired by the Hornline, it was enhanced, providing richer sound than was possible with the Horns alone, thus overcoming the single biggest drawback to the performance of the Horns when used by themselves.

Using the Hornline with different speakers revealed strengths and weaknesses, primarily in its ability to integrate well with different speaker designs. With one exception, all speakers tried with the Hornline integrated very well. As expected, best integration with different speakers required adjustment of Hornline and speaker positions, crossover frequency, phase, and relative volume.

Positive Impressions

The most important aspect of the Hornline is its quality of bass. Bass transients are notably quick and clean. When properly set up, it is never hollow or booming, and overhanging notes are minimal and rare. The Hornline seems to preserve the rhythm and timing of music better than most competitively-priced, conventional subwoofers.

Integration of a sub with main speakers is nearly as important as sound quality. The subwoofer should never call attention to itself, it should be audibly indistinguishable from the main speakers. To this end, the Hornline works exceptionally well with some speakers, and very well with others. Of the speakers available, the Hornline integrated seamlessly with the Horn Shoppe Horns. Not only does it share similar design and construction features with the Horns, but the Hornline was voiced using the Horns as main speakers.

[Binding Posts]

Top of Hornline back, showing binding posts.

The Hornline integrated equally well with a pair of Reynaud Twins. While the Twins are a 2-way design (3-way electrically), they use transmission line cabinets. The best setup with the Twins used a pair of IRD MB-100 monoblocs for power. This resulted in output that was not as delicately detailed and lacked the elegant microdynamics of the Horns powered by an SET amp, but made up for it with macro dynamics and visceral impact that is difficult to match with a two or three watt amplifier - unless very efficient speakers are used.

The Hornline worked nearly as well with two pairs of bass-reflex speakers, B&W DM602 and nOrh SM5.1, providing bass extension below the main speakers that was almost always indistinguishable from the mains. Due to the lower efficiency of these speakers, the IRD monoblocs were used with both pairs during testing.

Additionally, the Hornline did an admirable job when coupled with a pair of DIY open baffle speakers based on a pair of vintage Electro-Voice drivers. Since the open baffle design had difficulty making bass below about 110Hz, the Hornline amp was adjusted to fill in at higher than usual frequencies. The result was surprisingly good, and integration, while not quite seamless, was more than acceptable. Despite the openness and sometimes excruciating clarity of the EV speakers, the Hornline kept up with demands and provided bass that was equally clean with clarity that complemented the output of the EVs. Despite how well it worked, it did, however, seem odd to use 12-inch drivers to produce upper bass and mid-range (with a coaxial compression horn tweeter for frequencies above 3500Hz), while a 6 1/2 inch driver produced the low bass.

The Hornline is built with the same care and craftsmanship that Ed and his father use when building the Horns. As with the Horns, one benefit of the folded horn design is an extremely rigid and non-resonant cabinet. The Hornline is more solid and less resonant than most conventional subwoofers, helping to eliminate one source of subwoofer 'booming'. The fit is excellent and the finish is smooth, even, and well done, although it lacks the furniture-grade quality of some speakers.

Room placement did not seem to be a big issue with the Hornline. It worked well next to walls, away from walls, to the side of the listening position, behind the listening position, and almost anywhere else it could be placed. Naturally, position is best adjusted to complement room acoustics and the main speakers in use. There were only two places that I did not like its performance. When used in a small room, the Hornline should NOT be placed between the main speakers. Soundstage and music clarity suffered with this configuration. In addition, if placing the Hornline in a corner, great care must be taken with bass volume, as this was the only configuration that allowed 'booming' when using the Hornline.

Of particular note to potential buyers of Horn Shoppe products, especially those who have no opportunity to hear the Hornline before buying, is Ed's 3-day guaranty. If you do not like the product, simply return it within 30-days for a refund.

Negative Observations

While the Hornline integrates so well with many speakers that it is "invisible", it does not integrate equally well with all. This is by no means a problem unique to the Hornline, as most subs will integrate better with some main speakers than with others. In my limited evaluation, the Hornline integrated best with the Horns (rear-loaded horns) and Twins (transmission lines), but less so with bass-reflex speakers. Even so, it worked very well with two disparate designs of two-way, bass-reflex - the B&W DM602 (2-way, ported, reinforced box), and nOrh SM5.1s (2-way, ported, synthetic marble inverted horn), while being less forgiving with the third, a pair of Omega TS-1 speakers. The Omegas are single-driver speakers in a bass reflex cabinet.

[Horn Shoppe Hornline and Horn]

Top of Hornline back, showing binding posts.

When trying to integrate the Hornline with the TS-1s, the Hornline always sounded slightly different than the mains. Regardless of the phase setting, frequency cutoff, or placement, if the Hornline was set loud enough to augment bass, it was audibly distinct from the Omegas. Some listeners did not find this effect annoying, or even apparent, but I note it here because it may be an issue with some people. Out of curiosity, I substituted a Parts Express Titanic subwoofer (normally used for HT) for the Hornline. After crossover frequency and phase adjustment, the improvement in integration with the Omegas was readily apparent. Was it because the Titanic has greater adjustability, including a variable phase control rather than the 180-degree phase switch of the amp included with the Hornline, or was it because of the design difference? Those questions will be answered during further listening.

The Hornline has usable bass only to about 30Hz in my listening room. As my listening room is notoriously bass-shy, results could be better in a different environment. Many commercial subs claim response down into the low-20Hz range. Still, 30Hz is lower than the majority of music reaches and will be more than adequate for most people all the time, and for the rest of the people most of the time.

While the Hornline provides high-quality bass, it is not a match for live music - but then, what is? In particular, while listening to a recent Benise concert, the power of the large Chinese drum was as impressive to feel as it was to hear. Playing back the recording on the Mediterranea CD was somewhat disappointing. While the Hornline did a fair job of capturing the sharpness of the sound, it couldn't approach the power.

[Plate Amplifier]

Plate amplifier in separate box.

By contrast, the Titanic subwoofer was better at mimicking the power, but the impact of the drumsticks (more like drum clubs) came out muddled and soggy sounding. In all fairness, I have tried this recording on several other speaker/subwoofer combinations, and none performed any better the Hornline combined with DIY Electro-Voice main speakers. As good as the Hornline is, there is no substitute for live.

One other issue with the Hornline deals with its visceral impact - it simply doesn't have as much as many other subwoofers. As such, when using the Hornline for home theater, explosions lack the weight one expects. In movies that have a hip-hop soundtrack, bass lacks the deep, pounding, wall-shaking quality so beloved by the segment of the population that listens to such music. However, it seems a fair tradeoff - clean, musical bass, useful for most music types, as opposed to pounding, window-rattling power.

The separate amplifier box for the Hornline is an audiophile's delight, as it makes tweaking and switching amplifiers much easier than with most subwoofers. However, it adds to mess and clutter earning a relatively low WAF - unless the clutter can be cleverly hidden.


Not all subwoofers are created equal. It seems that subs suitable for movies are generally not well-suited for most music types. Conversely, subs designed and executed with music as their priority often lack the necessary impact to convincingly replicate Tyrannosaur footsteps.

Despite its unique design, there are high-order bandpass designs and the rare bass horns that share more in common with the Hornline than the Hornline does with conventional subs. So, the Hornline really isn't alone. Additionally, all subs were designed to augment bass. What the Hornline does it to augment the lower end of the audible spectrum affordably, and it generally seems easy to integrate into a variety of existing systems - even more so when considering the ease with which other crossovers and amplifiers can be incorporated to work with the Hornline, speaker using other custom amplifier/crossover setups.

Ed "Just-Don't-Call-It-a-Sub" Schilling vehemently insists that the Hornline is not a subwoofer, but instead is a 'bass augmenter'. I remain generally opposed to the idea of creating new terms to name products or ideas for which sufficient vocabulary already exists. Yet, when comparing the design of the Hornline to a conventional sub, the case can be made that it is sufficiently different to perhaps warrant a different label. Based on the clean, very musical performance, and unconventional design, the Hornline may very well qualify as a "bass augmenter" rather than a subwoofer. Okay, Ed, there it is in print!

P.S - Since I purchased this unit for personal use, then decided to write a review, the time finally has come for real experimentation begins. This will include building a low-pass filter and trying a variety of amplifiers to find the best way to power the Hornline. I also think I need two of them...

Many thanks to Ed Schilling of The Hornshoppe, for providing background information and the sample used in this review.

© Copyright 2004 Richard George - https://www.tnt-audio.com

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