I don't really consider Bang & Olufsen as high end, but now it seems they might at least done something interesting:
The BeoLab 5
2x250w + 2x1000w sound a bit like overkill to me, or is just their Icepower watts are 1/4 of a normal watt?
Have anyone heard a speaker using Acoustic Lens Technology?
Sausalito Audio Works have some whitepapers on thier site:
www.sawonline.com
The BeoLab 5
2x250w + 2x1000w sound a bit like overkill to me, or is just their Icepower watts are 1/4 of a normal watt?
Have anyone heard a speaker using Acoustic Lens Technology?
Sausalito Audio Works have some whitepapers on thier site:
www.sawonline.com
many years ago JBL etc put a piece of plastic in front of the metal dome tweeter and called it an acoustic lens. what you describ here is something quite different.
1. the proof of the pudding is in teh eating. listen to the speakers and you should get your answers
2. instinctivly i dont like it but i culd be wrong seems like putting a piece of plastic, ceramic or whatever near a driver to shape it's dispersion is asking for trouble.
3. other drivers have used wave vguides o shape the HF charteristics of their tweeters (SS's 9900 comes to mind) but none of those guides have been as radical as this
1. the proof of the pudding is in teh eating. listen to the speakers and you should get your answers
2. instinctivly i dont like it but i culd be wrong seems like putting a piece of plastic, ceramic or whatever near a driver to shape it's dispersion is asking for trouble.
3. other drivers have used wave vguides o shape the HF charteristics of their tweeters (SS's 9900 comes to mind) but none of those guides have been as radical as this
this came from another thread but i thnk the concept is related
http://www.duevelloudspeaker.com/loudspeaker.htm
http://www.duevelloudspeaker.com/loudspeaker.htm
Those drivers must be almost perfect dummy loads: 5 kW in total for achieving just 108 dB !!! 
The shown acoustic lenses are a seemingly more refined method of what's been done already (today, many things can be modelled accurately and conveniently on a computer). There are many omnidirectional speakers using simple conus shaped reflectors to achieve the same.
ICE power modules are PWM (i.e. class - d) amplifiers with a special multiloop feedback technology.
I have difficulties to understand how, for aestetical design's sake, one can deliberately build a low efficiency speaker with high-efficiency amplifiers in the kilowatt range, to end up with SPLs also achieved by the better ghetto blasters !?
Regards
Charles
The shown acoustic lenses are a seemingly more refined method of what's been done already (today, many things can be modelled accurately and conveniently on a computer). There are many omnidirectional speakers using simple conus shaped reflectors to achieve the same.
ICE power modules are PWM (i.e. class - d) amplifiers with a special multiloop feedback technology.
I have difficulties to understand how, for aestetical design's sake, one can deliberately build a low efficiency speaker with high-efficiency amplifiers in the kilowatt range, to end up with SPLs also achieved by the better ghetto blasters !?
Regards
Charles
Bose calls this piece of plastic a spatial lens.....
My first words upon seeing the picture of these speakers..."What the heck is that?" Looks terrific, ofcourse, its all in the listening which is what I wnat to do with those. Unfortunately I guarantee no shop around my area has those, so, maybe when I hit the streets to Hollywood or somewhere, I'll get a chance to listen to those.
My first words upon seeing the picture of these speakers..."What the heck is that?" Looks terrific, ofcourse, its all in the listening which is what I wnat to do with those. Unfortunately I guarantee no shop around my area has those, so, maybe when I hit the streets to Hollywood or somewhere, I'll get a chance to listen to those.
Yuck...
Read the section on "adaptive bass" whateverthehelltheycallit....
If I'm reading it correctly, it increases bass response at "normal" listening levels, and throttles it back to avoid driver abuse... so if I decide I like a song and turn it up louder, only the treble gets louder...
Sorry folks... that's exactly the opposite of what I want to happen. When I turn up the music, I want the bass to get louder first.
Read the section on "adaptive bass" whateverthehelltheycallit....
If I'm reading it correctly, it increases bass response at "normal" listening levels, and throttles it back to avoid driver abuse... so if I decide I like a song and turn it up louder, only the treble gets louder...
Sorry folks... that's exactly the opposite of what I want to happen. When I turn up the music, I want the bass to get louder first.
Such circuits do only reduce the level at the very low end in order to protect the driver from overexcursion.
This is nothing new basically: KLH did it a quarter of a century ago, many P.A. manufacturers do it (Meyer, Renkus-Heinz, Hitec Audio, D&B to name a few).
Regards
Charles
Edit: Forgot to mention they reduce only if needed, i.e. they "analyse" the spectral content and compare it to the FR of the driver-excursion.
This is nothing new basically: KLH did it a quarter of a century ago, many P.A. manufacturers do it (Meyer, Renkus-Heinz, Hitec Audio, D&B to name a few).
Regards
Charles
Edit: Forgot to mention they reduce only if needed, i.e. they "analyse" the spectral content and compare it to the FR of the driver-excursion.
KLH was one of the first. Was that Henry Kloss again?
They made small boxes that went deep using bass EQ. the bass EQ faded at louder levels to prevent over excursion and in keeping with Fletcher Munson (I hope I got the right) curves which dictated the sensitivity of the human ear at various SPLs.
They made small boxes that went deep using bass EQ. the bass EQ faded at louder levels to prevent over excursion and in keeping with Fletcher Munson (I hope I got the right) curves which dictated the sensitivity of the human ear at various SPLs.
I have a JAES article about the KLH thingie, written by Daniel von Recklinghausen. As far as I remember they mainly took care of the driver excursion.
I have also once seen the B&O patent. I don't remember the exact details but I vaguely recall something like a subtractive crossover whose outputs are summed again after the lower branch signal has passed a VCA which is controlled by an excursion detection circuit.
Exursion is usually modelled within such controllers by a lowpass filter that is followed by a level detector. For closed boxes this is a second order lowpass filter and for vented systems it is a 2nd order lowpass with a notch.
The KLH 2nd order equalising/protection HPF is using a JFET as an electrically controllable resistor.
It does alter the filter's Q (and therefore boost as well) and also the pole frequency.
I once made experiments with an OTA instead and even made a LAB report about it at the scool of engineering (I used the oldfashioned CA3080 back then).
Another famous boost circuit with excursion control is the ELF circuit as it is used by BagEnd for instance.
Regards
Charles
I have also once seen the B&O patent. I don't remember the exact details but I vaguely recall something like a subtractive crossover whose outputs are summed again after the lower branch signal has passed a VCA which is controlled by an excursion detection circuit.
Exursion is usually modelled within such controllers by a lowpass filter that is followed by a level detector. For closed boxes this is a second order lowpass filter and for vented systems it is a 2nd order lowpass with a notch.
The KLH 2nd order equalising/protection HPF is using a JFET as an electrically controllable resistor.
It does alter the filter's Q (and therefore boost as well) and also the pole frequency.
I once made experiments with an OTA instead and even made a LAB report about it at the scool of engineering (I used the oldfashioned CA3080 back then).
Another famous boost circuit with excursion control is the ELF circuit as it is used by BagEnd for instance.
Regards
Charles
One of the best reasons for education, weather formal or into life experience is meeting someone who can in a few days or weeks drop a few ideas into your head that will influence you for years.
More years ago than I like to recall I stumbled into an acoustics class being taught by a guy named Dave Moulton.
http://moultonlabs.com/index.htm
It was a great class that’s been an immeasurable help in both my personal and professional life
At the time I was taking the class Dave was working on either the 1st or 2nd generation of the acoustic lens technology that evolved into the product licensed by Sausalito to Bang and Olufson.
I haven’t heard the latest generation of products, but I know the early technology was impressive way back in the mid 80's
More years ago than I like to recall I stumbled into an acoustics class being taught by a guy named Dave Moulton.
http://moultonlabs.com/index.htm
It was a great class that’s been an immeasurable help in both my personal and professional life
At the time I was taking the class Dave was working on either the 1st or 2nd generation of the acoustic lens technology that evolved into the product licensed by Sausalito to Bang and Olufson.
I haven’t heard the latest generation of products, but I know the early technology was impressive way back in the mid 80's
I just had a glimpse at the new issue of the German mag "audio" (some people here might want to throw flames at me only just for having done that ) and there was a test of this B&O thingie.
While the acoustic lens technology might be a good thing to control spatial radiation (which is always a good idead of course) two other things I regard as being plain ridiculous:
1.) Why pump 5 kW in total (which would be enough for a rock gig in a medium sized venue, given the right type of speakers) of amp power in two speakers that only achieve 108 dB SPL/pair ?
2.) Why the hell do they use a DSP and then they achieve an amplitude response and step response that is nothing special (to say the least) ? Especially the step response (looks as most speaker's step response does:the responses show up in single file, staring with the tweeter's response) should be better from a company that once invented the filler driver crossover !
They were once pioneers (tangential tonearm, filler driver etc) and migrated to someone building accessories for stylish homes that enable you to reproduce some elevator music. With this new Beolab5 they wanted to get back to the pioneering image they once had but I doubt that it is more than just lip service.
Regards
Charles
While the acoustic lens technology might be a good thing to control spatial radiation (which is always a good idead of course) two other things I regard as being plain ridiculous:
1.) Why pump 5 kW in total (which would be enough for a rock gig in a medium sized venue, given the right type of speakers) of amp power in two speakers that only achieve 108 dB SPL/pair ?
2.) Why the hell do they use a DSP and then they achieve an amplitude response and step response that is nothing special (to say the least) ? Especially the step response (looks as most speaker's step response does:the responses show up in single file, staring with the tweeter's response) should be better from a company that once invented the filler driver crossover !
They were once pioneers (tangential tonearm, filler driver etc) and migrated to someone building accessories for stylish homes that enable you to reproduce some elevator music. With this new Beolab5 they wanted to get back to the pioneering image they once had but I doubt that it is more than just lip service.
Regards
Charles
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