Power
The amplifiers are made up of 1000W each for the main and upper woofers, together with 250W each for the midrange and tweeter giving a total of 2500W output. “Such power permits B&O to address the issues of thermal power compression (by calculating it and adding back sufficient gain offset) and to run effortlessly at something approaching real concert hall levels (i.e. sustained real-world levels of 108 dB SPL with peaks of 120 dB SPL, should you care to entertain all of the folks on your block). A typical high — end audiophile speaker system with two gigantic mono — block amplifiers running at 500 W apiece will run out of steam at probably 10 dB below these levels, all other things being equal. Such power also means that at all sane levels, the BeoLab 5 is simply loafing along, never stressed in the slightest, and if you encounter any signs of distortion, you can know for sure it is occurring elsewhere in your signal path.
Finally, the speaker is fully digital, so you can plug in an S/PDIF feed if you wish. The A/D and D/A converters are of extremely high quality, so no problems will be encountered there either. But the real payoff is that extensive DSP is present, which permits each speaker to be quickly and precisely matched (+/- .25 dB) and documented during manufacture. This, to my mind, is a huge breakthrough. It means that for all intents and purposes, speakers will not be audibly different (a first for mass-produced speakers), and because of thedocumentation, they can be maintained to hold that tolerance! (Just so you know, there’s an RS 232 port included, so the speaker can “talk” to the factory and its DSP is recalibrated to accept a replacement driver).” (Source)
The new technology:
Acoustic Lens Technology (ATL) * – invented by Dave Moulton and Manny LaCarrubba of Sausalito Audio Works LLC – which delivers sound in a 180 degree horizontal plane unlike ‘normal’ speakers which aim their sound directly away from themselves and towards the listener. The ATL technology is a new and effective means to redistribute the acoustic power of a conventional dome radiator. The resultant dispersion pattern has a very uniform frequency response over an extremely wide horizontal coverage angle
Adaptive Bass Control (ABC) actually ‘listens’ to the ambient sound within the room in which BeoLab 5 is placed and adjusts its output to suit the listening position
ABL (Adaptive Bass Linearisation)
As well as the two brand new technologies, BeoLab 5 employs Bang & Olufsen’s Adaptive Bass Linearisation which is a process patented by B&O and incorporated in newer (digital) BeoLab loudspeakers. The idea is to use the surplus capacity in amplifiers and driver units, arising by normal listening levels, for a bass extension – a sound reproduction with more bass, than the loudspeaker otherwise would be able to produce.
The function is adaptive. This means that the loudspeaker adapts to the signal it receives. Loudspeaker drivers are therefore fully exploited, without suffering mechanical or electronic abuse, and the built in amplifiers are not subjected to signals would otherwise create an overload situation.
ABL gives stunning bass reproduction considering the size of the loudspeaker in which it is incorporated, under normal listening levels.
Note: for BeoSound 9000 owners wish to use BeoLab 5 fully, there is a direct digital feed from the optical output of BeoSound 9000 (S/PDIF = Sony/Philips Digital Interface)
Acoustic Lens Technology for Loudspeakers: an introduction
Acoustic Lens Technology is a new and extremely effective means to improve the dispersion of high frequencies in loudspeakers, so that dispersion is much more uniform across the audible spectrum without the deleterious side-effects encountered with other engineering solutions to this problem.
The problem is fundamental: in an ideal loudspeaker it is axiomatic that frequency response should be flat across the audio spectrum. Flat response is designed for and measured “on-axis,” which is to say, in one direction only from the loudspeaker. In fact, the theoretical ideal loudspeaker (i.e. a pulsating sphere) should exhibit the same flat frequency response in all directions. Such a performance quality is, at the present time, impossible to achieve. All loudspeakers are more or less directional in output. Worse, loudspeaker directionality varies wildly as a function of frequency, crossover design and driver size.
So, not only is it virtually impossible for a loudspeaker to have a flat frequency response in all directions, it is equally difficult for a loudspeaker to have constant frequency response in all directions. As a rule of thumb, loudspeakers are omni-directional at low frequencies and highly directional at high frequencies, with erratic variations in between, particularly near cross-over frequencies.
We all have to accept this universal deficiency of loudspeakers. The cost of this deficiency is significant in terms of the quality of musical illusion, imaging and timbral accuracy in stereophonic music playback. Acoustic Lens Technology represents a successful effort to reduce this deficiency.
Acoustic Lens Technology is the outgrowth of more than a decade of invention, research and development. The lenses gather the sound output of a given speaker driver, re-focus it and emit it in the desired directions. Specifically, we have worked to develop a speaker with essentially flat frequency response to 15 kHz that remains constant across a horizontal angle of at least 180° with no lobing, phase anomalies, interference patterns or other undesirable side effects, and a vertical angle of 30°. At the same time, we have made Acoustic Lens Technology compatible with conventional drivers, comparatively inexpensive to manufacture, and reasonably small in size.
Speakers using Acoustic Lens Technology exhibit excellent imaging, depth of illusion and compelling timbral quality. Further, they exhibit an excellent “invisibility,” or sense of not being the source of sound. In surround sound production applications, Acoustic Lens Technology is extraordinarily effective for all speakers in the system.
* ATL Technology is licensed from Sausalito Audio Works LLC
For further information on Acoustic Lens Technology and Dave Moulton – developer of ALT – visit his site by clicking here.
“In BeoLab 5 design and acoustic engineering converge in the world’s most complete and powerful all-digital loudspeaker ever designed for use in domestic surroundings. The result is an intelligent loudspeaker with a pure and transparent sound uncoloured by the placement of the loudspeakers, the room itself or by your own listening position”
BeoLab 5 & Acoustic Lens Technology
ALT is short for Acoustic Lens Technology and is a patented geometric shape that when properly mated to a conventional dome radiator yields an extremely wide, uniform horizontal dispersion characteristic. Acoustic Lenses redistribute the sound power of a driver (a tweeter, for instance) such that the resulting dispersion is very uniform over at least 180° horizontally. The vertical radiation pattern is asymmetrical. It is limited such that very little sound is directed towards the floor. Somewhat more energy is directed upwards than towards the floor but, in general, the radiation pattern may be described as a ‘hemidisc’.
ALT’s unique dispersion characteristics help in several ways. The most obvious is that listeners seated off-axis hear virtually the same timbre as those on the reference axis. An ALT loudspeaker has a flatter power response curve than a conventional loudspeaker. This means that the total sound energy radiated by the speaker is more closely related to the axial frequency response or direct sound. This type of behaviour correlates positively with listener preference in controlled listening tests. This is why some manufacturers have rear firing tweeters. ALT does this while minimising reflections from the floor and the wall behind the speaker. The Archimedes Project, a 5-year multimillion dollar research project that delved into the relationships between acoustic reflections and the perception of timbre, revealed that such behaviour is desirable. Finally, ALT loads the driver to which it is mated so that less electrical energy needs to be applied to achieve the same SPL as a baffle-mounted driver. This increases power handling and lowers distortion. ALT does all of this while maintaining excellent axial frequency response.
Room placement of ALT speakers
As with most speakers, Sausalito Audio Works LLC – as inventors of the system – recommend placements of at least 1m and preferably 1.5m – 2m from any wall. Normally you would not aim an ALT speaker directly at the primary listening position – the reference axis for these speakers is 30° so it is advisable to keep them pointed straight ahead.
The only exception to this is if you must put the speaker less than 1m from a sidewall. In such an instance, aiming the speaker directly at the listening position usually yields better results.Sausalito also recommends that the primary listening position be located at the apex of the equilateral triangle formed by the speakers and the listener. Many audiophiles prefer to sit farther away from the speakers than this.
* ATL Technology is licensed from Sausalito Audio Works LLC
