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Topline Bob L 

“The TopLine L plays well-balanced, smooth and pleasant. The enclosure-less bass section sounds uniquely uncolored and free. Great class!”


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.

technical Data


Height: 1250mm

Height including Horn: 1750mm

Width Front: 300mm

Width Rear: 510mm

Depth: 355mm

Depth including Horn 565mm

Diameter Horn 750mm,


SPL: 91dB 1W/1m

Impedance: 4 Ohm

Crossover Frequencies: 4000 Hz / 570 Hz/ 37 Hz ( Active)

Frequency range: 20 Hz – 21000 Hz (-3dB)







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.


The basic idea was to build a smooth sounding speaker 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 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 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.