Backes & Mueller waveguide

[angeloitacare]

German high-end speaker manufacturer Backes & Mueller employs
a quit different waveguide in their top of the line BM35 and BM50 speakers. ( The BM50 costs over us$ 100.00,00 )

http://www.backesmueller.de/_site/#Produkte

If such a WG sounds good, it throws away all theories....

has somebody heard these speakers at some show ?

Angelo

[ScottG]

It's not that outrageous..

Consider that every compression driver *relies* on diffraction for operation.

They have just converted the point source into a line source via additional diffraction.

The waveguide is just that - p!ss little acoustic gain designed primarily to control the dispersion pattern. That large chamber operates as a "lower" freq. low pass filter - reducing the naturally exaggerated *higher* freq. response of most compression drivers. (..basically the opposite operation of most horns - which raise the *lower* freq. response with acoustic gain.)

One interesting thing to note:

..look at the "departure" angle of the interior wall of the front chamber as it connects to the waveguide (in relation to the waveguide).

[applehorn]

The B&M horn looks like the part used in the L'Acoustic PA cabinet.

Iain

[angeloitacare]

hi Scott

i thought diffraction was detriment to quality , and not desirable ?

[gedlee]

Originally posted by ScottG
Consider that every compression driver *relies* on diffraction for operation.

Hi Scott

How is that? I don't follow.

Originally posted by angeloitacare
i thought diffraction was detriment to quality , and not desirable ?

It is. Who said that they do that because it sounds better? Its more about image and looks than sound.

[ScottG]

Originally posted by gedlee

Hi Scott

How is that? I don't follow.

Me thinks you do..

[ScottG]

Originally posted by angeloitacare
hi Scott

i thought diffraction was detriment to quality , and not desirable ?

What Earl said.. But that's a generalized response.

How this application sounds to any particular listener? Don't know - could sound fantastic or cr@ppy, or likely somewhere in-between. (..not exactly a useful response either.)

I wouldn't "chuck" the idea simply because it utilizes diffraction. Again, if that was the case you wouldn't be using a compression driver - which "pushes" a relatively large, (wavelength size), grouping of wavelengths through a small opening. Sure - there is also the contribution of the phase plug, BUT its operation is also diffraction-based (.same song second verse, not quite the same as the first).

Note that this particular design will be considerably less efficient with greater non-linear distortion at lower freq.s. On the other hand it may still outperform a good tweeter in this respect (..depending on the performance of the compression driver).

[el`Ol]

I have heard the B&M at the Highend in Munich. Not better or worse than other highend speakers with compression driver, e.g. Duevel. What´s special about them is that the driver runs from 800Hz to 20kHz, but as they are active digital speakers this could be possible due to EQing as well, not necessarily due to the waveguide. Vertical beaming is extreme.

[phase_accurate]

I think the beaming is intended in order to reduce room interaction. For the same reason the low-mid drivers and the woofers are arranged such that vertical directrivity is increased.

Regards

Charles

[angeloitacare]

I have heard the B&M at the Highend in Munich. Not better or worse than other highend speakers with compression driver, e.g. Duevel.

the comment of TNT-Audio is remarkable:

http://www.tnt-audio.com/shows/munich07b_e.html

By comparison, the JBL had great bass, but rather fuzzy midrange and treble, while the BM35 excelled in mid and treble.

how can a BM35 , using a single, small format driver with a strange WG sound btetter than the Everest in the mid-treble ????

If it is true, as many state, that diffraction at the mouth and throat of a horn/WG are one of the main sources for coloration, this setup should sound crap....

in the meanwhile, german Audio.de has crowned the BM50 as their reference speaker system.....