For the record, around 100% of interior designers prefer ceiling speakers...sadly.
wide baffles and baffle step
Lengthy quotation from Peter Comeau, designer at Wharfedale. Makes a lot of sense to me...
"Th[e] larger ported box, with its subsequent increased baffle size, helps solve a major problem in modern speakers, namely, the baffle step.
I grew up with large speakers with wide baffles, but, as speakers reduced in size over the years I noticed that something was missing from the sound and, when I stuck my head firmly into speaker design, I began to understand the acoustic problems caused by the baffle step.
Put simply, as the baffle size decreases, the point at which the acoustic radiation changes from hemispherical to spherical goes up in frequency. It also becomes sharper and narrower in bandwidth as the sides of the cabinet, and the walls and floor of the room, are further removed from the equation. So, this 6dB step in the power response becomes acoustically more obvious.
I believe that a thin speaker always sounds thinner throughout the midrange when directly compared to a speaker with more generous baffle width. Of course, as designers of modern, slim speakers, we compromise by adjusting for the baffle step in the crossover, but in doing so, we also compromise sensitivity. What starts out as a 90dB at 1W drive-unit often ends up as an 85dB system once we have adjusted for the power loss due to the baffle step."
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This is what I think is sad. https://www.bluebirdmusic.com/edit/files/images/gallery/spendor_str_nov_18.jpg |
@audiokinesis With respect to baffle step compensation, unless the baffle is wide enough to impinge on the limits of room space and physical practicality there will be an audible 3db loss of all frequencies below the baffle step frequency. For example the baffle would need to be 33.76 in. wide for a frequency of 400 hz. With that width, frequencies below 400 hz will drop off by 3db relative to frequencies above 400 hz. Lower baffle step frequencies will require a wider baffle (increasingly less practical), the baffle can decrease in width for higher baffle step frequencies (increasingly practical). Example, 9 in. width for a 1500 hz. baffle step frequency, easily managed physically and electronically). With the loss in output of all frequencies below the baffle step frequency, some form of compensation will be required. A BSC circuit is a popular and effective method for doing so. |
@avanti1960 wrote: "With respect to baffle step compensation, unless the baffle is wide enough to impinge on the limits of room space and physical practicality there will be a 3db loss of all frequencies below the baffle step frequency. For example the baffle would need to be 33.76 in. wide for a frequency of 400 hz. With that width, frequencies below 400 hz will drop off by 3db relative to frequencies above 400 hz... "With the loss in output of all frequencies below the baffle step frequency, some form of compensation will be required. A BSC circuit is a popular and effective method for doing so." The baffle step happens gradually, so in practice we really don’t need 33.76" width in order to be good down to 400 Hz. AND that baffle-stepping side-spilling wrap-around energy isn’t "lost" - it just becomes off-axis energy. It arrives after some time delay and some attenuation due to path length and some absorption at the surfaces it reflects off of. In the meantime, the woofer’s radiation pattern is also trending towards omnidirectional at longer wavelengths. So as we go down in frequency, we are getting proportionally more reflected energy from two phenomena: Baffle-stepping and pattern-widening. Thus obviously as we go down in frequency, the room acoustic situation plays a progressively greater role in what we hear, especially with narrow speakers. In situations where the direct sound dominates, I can definitely see an argument for baffle step compensation. As the relative contribution of the reverberant energy at the listening position increases, imo baffle step compensation becomes less necessary and/or less desirable. I can easily see baffle step compensation being the right choice for a 9" wide speaker which is not designed to go up against the wall. I also think it’s a tradeoff, degrading the spectral balance of the reverberant sound for the sake of the first-arrival sound. And using a wide baffle is also a tradeoff. It’s a matter of picking one’s poison... or perhaps more precisely, picking the poison which is most palatable (and most practical) to the most potential buyers. And I’ll readily admit that’s NOT a 33.76" wide baffle! Duke |
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