THE IDEA BEHIND THE TOPLINE BOB XL

The concept behind the TopLine Bob XL high-end speaker was simple: build the best hi-fi speaker technically possible. It was to be a smooth sounding horn speaker with excellent impulse response.

Each Bob XL Hi-Fi speaker is driven by 3000 watts in the bass range and controlled by a DSP (Digital Sound Processor). This allows the bass response to be perfectly matched to the room.

The rest of the speakers operate passively, so you can use your favorite electronics from 40 Hz without having to drive power-hungry bass speakers. Only the finest components have been used for the crossover of the TopLine Bob XL high-end speakers. We paid attention to a linear phase and a perfect transient response and also focused on a very clean frequency response.

TOPLINE BOB XL HORN LOUDSPEAKER: THE MASTERPIECE FROM STEIN MUSIC
Perfect engineering is an absolutely essential aspect for us. Nevertheless, we believe that to create equipment that sounds outstanding, it takes more than that. Only in combination with excellent craftsmanship, a great deal of passion for music and decades of experience are we able to produce masterpieces like the TopLine horn loudspeakers.

Horn Technology
A horn has proven to be the best way to provide a perfect match of diaphragm movement to the air carrying the sound. So we have chosen this concept for the mid and high frequencies, as it significantly helps to obtain accurate low frequency information.

Horn technology is popularly used to increase the efficiency of a hi-fi speaker. However, this was not planned for the Bob XL, because in our opinion it usually leads to a somewhat thin and harsh sound. We also did not use compression drivers, for exactly the same reason. Instead, we put a lot of effort into achieving a perfect match between the horns and the drivers in the TopLine Bob XL horn speaker.

Open baffle
In the bass range, we opted for an open baffle. This way, the drivers are perfectly loaded on both sides in a balanced way. This is called the “open baffle principle”. Six of the bass speakers are mounted on each side of the cabinet, so we achieve excellent impulse compensation and very low resonances in the cabinet.

In addition, speakers with a large surface area should be used for the low frequencies. If smaller cone areas were used, they would have to be compensated by a larger excursion, which would then be much less linear. The large diaphragm area, on the other hand, requires a significantly reduced diaphragm excursion, so that the diaphragms always move within their linear range. This is how we get extremely low distortion in the TopLine Bob XL, and thus a really clean sound.

Carbon composite coating
In the lower midrange, five 10″ speakers with a total area of 320 square inches do their job, treated with a special carbon composite. The bass is reproduced by ten 12″ speakers that offer an area of more than 1500 square inches. The bass speakers were also treated with carbon composite.

REVIEWS

Jason Victor Serinus, May 25, 2022, at Stereophile magazine:

“…the Stein Music system produced good bass, lots of inviting midrange, and a smooth top. It triumphed through Youn Sun Nah’s ridiculous, both barrels loaded, over-the-top “Ghost Riders in the Sky,” and handsomely nailed the distinct timbre and body of the voices of Bryn Terfel and Simon Keenlyside performing an unusual arrangement of the opening movement of Pergolesi’s Stabat Mater. Color me impressed.“

Uwe Kirbach in Image HiFi 4/2022

“A real trade show highlight: Stein Music’s Topline Bob XL sparkled, beguiled or dynamically pushed you into your seat.”

Silvan Karrer in the Swiss AVguide magazine:

„Best Sound of the High End Show Munich 2022“

General characteristics of the SteinMusic Top Line Speaker series

• Open baffle for the non-horn loaded speakers achieves a perfect impulse response, as the speakers are not caged in a box.
• Big diaphragm surface (> 4m² for the XL subwoofers) so that the displacement of the diaphragms is always small and in the linear region.
• Horns for the higher frequencies excellently adopt the small displacement of the diaphragms to the air.
• The radiating characteristics of the bass is that way that they will not stimulate the room resonances.
• We use a line array for the deep mid frequencies, to achieve the same dispersion characteristics as the one from the horns.
• All speaker diaphragms are treated with carbon composite for a coherent sonic character form the deepest bass till the highest audible frequencies.
• Carefully selected drivers so that a very simple crossover with finest quality components may be used.
• To achieve the best possible quality, critical inductors and capacitors are made in house by SteinMusic
• All interior cable are specially designed for exactly the given purpose and precisely made by SteinMusic in Germany.
•  The active integrated subwoofers make the speakers easy to drive with amps from 30 watts onwards.
• The result is no typical speaker sound, but lots of music.

THE TOPLINE BOB XL SUBWOOFERS

Our TopLine Bob XL speakers can be expanded with the TopLine XL subwoofers to the Bob XL+. In it works an array of eight handmade 18″ drivers with over 2m² effective diaphragm area. They are mounted in a fully stabilized special cabinet with an open baffle and are driven by a DSP-controlled amplifier with an incredible 3000 watts of power. So we get a linear and uncompressed reproduction down to 17 Hz with 0 dB volume rolloff.

This distinguishes the Topline XL subwoofer from Stein Music

The subwoofer delivers a colorful, differentiated and clear bass down to the lowest octave, so that the higher frequencies can develop much better in their own working range. The TopLine XL subwoofer can be used in line-ups for both stereo and mono.

Modular system: More bass with the TopLine XL subwoofer

To expand the TopLine Bob XL horn loudspeakers to the Bob XL+ system, you can add the TopLine XL subwoofers. This gives you Stein Music’s largest and most powerful speaker system, which is a true sonic wonder, especially in larger rooms.

Features of Stein Music TopLine XL Subwoofers

• More than 2 m² effective diaphragm area in a TopLine XL subwoofer, i.e. 4 m² for the pair
• 17 Hz with 0 dB volume drop without any frequency linearization due to the integrated DSP
• Eight dedicated 18″ woofers per side of the TopLine XL Subwoofer open baffle with DSP controlled 3000 watts per side for uncompressed, deep, natural bass
• Colorful, differentiated and clear bass all the way down to the lowest octave lets the higher frequencies come through much better

RECOMMENDATION

TopLine Bob XL+ horn speakers are designed in combination with all our other original audio solutions and Hi-Fi accessories. Therefore, we recommend Stein Music amplifiers and cables. Stein Music products are the perfect complement to unlock the full potential of the TopLine Bob XL+ speaker.

However, you can drive the speakers with a wide range of solid-state, digital, tube or hybrid amplifiers. Since the speakers and subwoofers are self-powered in the bass range, the power of the amplifier does not need to be as high as you might think given the TopLine Bob XL+. Since the amplifier only needs to serve the frequencies above 40 Hz, you can therefore focus on the sound you like rather than the power.

With the Bob XL+ combination, 60 watts of tube, hybrid or solid-state amplifiers are perfectly adequate for moderate volumes. If you want to play the music loud, 120 watts is enough. Amplifiers with more than 1000 watts per channel can also deliver pleasing results.

A SPEAKER THAT GROWS WITH YOUR NEEDS

HIGHLINE BOBBY M

The HighLine Bobby M is a sophisticated floorstanding speaker system that is created by combining the HighLine Bobby S and the HighLine Bobby Bass Extension.

This 240-watt all-passive set surprises the listener with a clarity and structure in the lower octaves that is completely unusual for its size. At the same time, it focuses on authenticity and presence in the midrange and treble.

The Bobby Bass Extension is specifically designed to perfectly extend the capabilities of the Bobby S and Bobby S Signature monitor speakers to the size and power of a floorstanding speaker.

The Bobby Bass Extension is a passive box with an integrated crossover that is perfectly matched to the Bobby S horn speakers. It has just the right height to serve as a stand for the Bobby S horn speakers.

Just like the Bobby S, the body of the Bass Extension is trapezoidal and tapers from the back to the front.

Reviews

Julie Mullins – The Absolute Sound

“it is special, indeed, offering beautifully pure and natural, airy sound in a unique and versatile modular package”

Volker Frech – Lite Magazin

“As a horn speaker, the HighLine “Bobby” M captivates the listener with its reproduction of voices and solo instruments. As before, the “Bobby” M with its sound selector switches offers the possibility to make an adjustment to the listening room or one’s own taste, the differences are now, in the three-way version, even more pronounced.”

Driver

— FINELY SELECTED AND MODIFIED

As bass speakers we use 2 pieces of the same 6” speaker with a carbon coated natural fiber cone, and extremely little mechanical losses as in the Bobby S. By this we ensure to get a sonic characteristics which perfectly fits to the Bobby S. The diaphragms of the bass is also treated with SteinMusic Maestro lacquer.

This treatment gives a very natural sonic signature, which is equal all over the entire frequency range that the Bobby M or L is able to reproduce. We source those drivers from one of the best manufacturers, and besides the cone treatments we further modify and optimize them in many aspects to reduce mechanical losses and get an open sound with lots of detail and no colorations.

Wiring

The internal wiring is made of the finest solid core copper conductors. The diameter for the bass is 1mm, for the tweeter we use exactly the same style of conductors but decreased the diameter to 0,5mm. The result is a better resolution of the higher frequencies, maintaining a coherent overall reproduction. All cables we use in our horn loudspeakers are produced on our own braiding machines in order to constantly achieve the best result.

Crossover

— HANDMADE AND DEVELOPED INHOUSE

Before designing a crossover, we have carefully matched and adjusted the drivers so that we can achieve the best results with a simple configuration here, which ensures that no details of the music are lost in this area of the speaker.

Each component of the crossover was selected after extensive listening tests. The most critical capacitor for the tweeter is an oil-impregnated film capacitor. We chose our favorite capacitor in terms of sound from the Mundorf range. We receive these as raw windings and process them in our factory according to our ideas and experience to produce a capacitor with a unique, fine, expressive sound without discoloration. The coil in the bass section consists of individually insulated strands, and as resistors we use exclusively our preferred film resistors from Beyschlag.

In addition to the classic components used in a crossover, we also work here with our self-developed InLine Matrix components to avoid magnetic distortion.

Cabinet

— MANUFACTURED IN OUR WORKSHOP

Cabinet Bobby S
The cabinet is a ventilated cabinet with short tubes in the front behind the high frequency horn. It is wider at the back than at the front in a precisely defined ratio, which we have empirically found to be the best solution. An important aspect of this construction is that there are no standing waves between the side walls. Secondly, in combination with the 40mm thick rear panel, it gives the cabinets enormous stability against unwanted resonances. This allows us to work without any internal damping material, which not only absorbs unwanted resonances, but also takes energy out of the music. The Bobby S are equipped with solid walnut feet for a transparent but organic sound.

Cabinet Bobby Bass Extension
The housing is a vented box. The bass reflex tunnels are located close to the bottom, and we have chosen a contour that changes its diameter slowly over the length. Be this we get a much better contour of the bass. The housing is wider in the back than in the front in an exactly defined ratio that we empirically found out to be the best solution here. One important aspect of this construction is that we will not have standing waves between the sidewalls, which in addition are stiffened with a bar. This gives the housings an enormous stability against unwanted housing resonances. This allows us to work completely without any internal dampening material, which does not only absorb unwanted resonances but also always sucks out energy from the music. Also the Bobby Bass Extension are equipped with solid walnut feet for a transparent but organic sound.

Terminals

There are two toggle switches on the connection plate of the Highline Bobby S horn speakers. These can be used to adjust the character and volume of the high frequencies, depending on the positioning, characteristics of the listening room and personal preferences. No additional switches are necessary with the Bobby Bass Extensions.

If the Bass Extension and the Bobby S are combined into a Bobby M or a Bobby L, they are automatically included in the adjustments. However, depending on the positioning and characteristics of the listening room and personal preferences, you can use the supplied acoustic foam parts in one or both bass reflex channels for adjustment.

Components

Each component of the crossover is of the best quality and was chosen after extensive listening tests. The most critical capacitor for the tweeter is an oil-impregnated film capacitor.

We have opted for our favourite Mundorf capacitor in terms of sound. We receive these as raw windings and process them in our company according to our ideas and experience to a capacitor with a unique, fine, expressive sound without discolouration. The coil in the bass range consists of individually insulated strands, and we use only our preferred Beyschlag film resistors as resistors. In addition to the classic components used in a crossover, we also use our proprietary InLine Matrix components to avoid magnetic distortions.

Specials

All drivers, crossover components, terminals and cables are processed with a special in house developed technology reduce material stress, and so increase the conductivity for complex signals. In addition, we do use our unique quantum physical approach that you also find in our E-Pads. Bobby S and Bobby Bass Extensions are equipped with solid walnut feet for a transparent but organic sound. In addition the Bobby Bass Extensions have receptions for these feet from the Bobby S in their top, and the contact surface is massive mahogany.

HANDCRAFTED MASTERPIECE

TOPLINE BOB L

The Top Line “Bob” L has the same footprint as the Top Line “Bob” XL, with only two thirds of the height. Each speaker has an integrated, DSP-controlled active subwoofer with 1500 watt amplifier power. The rest of the loudspeaker works passively, with optimal reproduction down to 60Hz.

Modular System Our Top Line Bob L horn speakers can be upgraded in many ways for an even better music experience. The Top Line Bob L can be converted to a Bob XL with the “Bob XL Upgrade”. If you want to achieve even more power with your Bob L, there is the possibility to link it with our Bob L subwoofer. If that’s not enough you can upgrade your Bob XL to a Bob XL+ which includes an additional subwoofer to the Bob XL.

Reviews

Holger Barske- Hifi Test

“The Topline L plays  well-balanced, smooth and pleasant. The Enclosure-less Bass Section Sounds uniquely uncolored and Free. Great Class ! ”

Jason Victor Serinus – Stereophile

“The Topline Bob L delivered an arresting three-dimensional soundstage and marvelous range of colors.”

“Masterful Sound Artistry: The TopLine Bob L High-End Loudspeakers”

On each side of the TopLine Bob L High-End Loudspeakers, three bass speakers are mounted, enabling excellent impulse compensation and minimal resonances within the enclosure. Each Bob L speaker is powered by 1500 watts in the bass range and controlled through a Digital Sound Processor (DSP) to perfectly tailor bass reproduction to the room.

Conversely, the mid and high-range speakers operate passively. As a result, you can utilize your preferred electronics from 40 Hz upwards. In the crossover, we exclusively incorporated top-quality components. Our focus was not solely on an exceptional frequency response; we also prioritized maintaining a linear phase and achieving impeccable transient response.

We firmly believe that crafting devices with outstanding sound requires more than just impeccable technology, which is undoubtedly a crucial factor. However, it’s the combination of excellent craftsmanship, a passion for music, and extensive experience that empowers us to create masterpieces like the TopLine horn loudspeakers.

General characteristics of the SteinMusic Top Line Speaker series

• Open baffle for the non-horn loaded speakers achieves a perfect impulse response, as the speakers are not caged in a box.
• Big diaphragm surface (> 4m² for the XL subwoofers) so that the displacement of the diaphragms is always small and in the linear region.
• Horns for the higher frequencies excellently adopt the small displacement of the diaphragms to the air.
• The radiating characteristics of the bass is that way that they will not stimulate the room resonances.
• We use a line array for the deep mid frequencies, to achieve the same dispersion characteristics as the one from the horns.
• All speaker diaphragms are treated with carbon composite for a coherent sonic character form the deepest bass till the highest audible frequencies.
• Carefully selected drivers so that a very simple crossover with finest quality components may be used.
• To achieve the best possible quality, critical inductors and capacitors are made in house by SteinMusic
• All interior cable are specially designed for exactly the given purpose and precisely made by SteinMusic in Germany.
• The active integrated subwoofers make the speakers easy to drive with amps from 30 watts onwards.
• The result is no typical speaker sound, but lots of music.

The Top Line “Bob” M Hornloudspeaker demonstrates the symbiosis of high-end sound and slim design.

Based on the concept of the Top Line “Bob” L Hornloudspeaker, with a smaller footprint. Here works a combination of horn speakers, four passive 8″ carbon coated Paper low-mid tone chassis and 8 DSP-controlled active 10″ subwoofers with an amplifier power of 1500 watts.

This universal talent also follows the open-baffle principle. This design completely dispenses with the inherent sounds of enclosures and does not require any damping. Only in this way can you actually hear your electronic chain “breathe”. With the Top Line “Bob” M you can enjoy and experience music in its most vivid form and feel the soul of music in every single octave.

Reviews

Audiotest Magazine 07/2018

“Yet (The Bob M) does not sound Technocratic at all, but incomparably Alive. With the Top Line, Holger Stein has succeeded in creating a Real Acoustic Milestone.”

Johannes Strom – Like Hifi Magazin

“A new discovery for us as well, because for a moment you actually think you left the window open and dare to look outside and gaze at the sky, only to realize that the realism of the reproduction is so excellent that we were deceived into an acoustic hologram.”

The basic idea was to build a smooth sounding Hornloudspeaker with excellent impulse response. A horn gives a perfect adaption of the diaphragm movement to the air that then transports the sound. We have been choosing this concept for the mid and high frequencies as it significantly helps getting accurate low level information. The idea was not to increase the efficiency, as doing this often tends to result in a clear but somewhat thin and harsh sound. Also we did not use compression drivers for exactly the same reason, but spend a lot of effort into a perfect matching between horns and drivers.

For the lower frequencies we decide to use an open baffle, as this concept perfectly loads the speakers at both sides in a balanced way. We also choose to go for speakers with a big surface: Smaller cone area surface needs to be compensated by excursion, which is much less linear.
Having a large cone area means a significantly reduced cone displacement, so that the cones always move in their linear region, creating extremely low distortions. In the lower midrange four 8” Kevlar cones treated with a special carbon composite are doing their job. The bass is reproduced by 8 pieces of carbon composite treated10” speakers, which provide an effective surface of more than 500 square inches.

Four of the bass speakers are mounted on each side of the speakers, which gives an excellent
impulse compensation and very low resonances in the housing.

Each speaker is powered by 1500 Watts in the bass section, and controlled by a DSP to perfectly adapt the bass response to the room. The rest of the speakers works passive, so that you may use your favorite electronics from 55Hz upwards.

Only the best components are used in the crossover, and we did not only care for an excellent frequency response, but also a linear phase and a perfect transient response. Perfect technique for us is an absolutely essential aspect.

But we believe creating devices which finally sound good need more.
For us this is an art, like building a master violin, where good skills are essential but not sufficient.

General characteristics of the Stein Music Top Line Speaker series

• Open baffle for the non horn loaded speakers achieves a perfect impulse response as the speakers are not caged in a box.

• Big diaphragm surface (> 4m² for the XL subwoofers) so that the displacement of the diaphragms is always small and in the linear region.

• Horns for the higher frequencies excellently adopt the small displacement of the diaphragms to the air.

• The radiating characteristics of the bass are chosen that way that they will not stimulate the room resonances.

• Line array for the deep mid frequencies which has the same dispersion characteristics as the horns.

• All speaker diaphragms are treated with carbon composite for a coherent sonic character form the deepest bass till the highest audible frequencies.

• Carefully selected drivers so that a very simple crossover with finest quality components may be used.

• Active integrated subwoofers, which makes the speakers easy to drive with amps > 30 watts.

• No typical horn sound, just lots of music.