Tony L
Administrator
Does baffle diffraction not affect the bass driver too?
Rob has just answered far better and more concisely than I could to be honest. I had a post ready, but I’d not considered the efficiency benefit.
Does baffle diffraction not affect the bass driver too?
fab ... one day you can translate that for me as a plebFWIW up to and including the K series and the System 15DMT, Tannoy did not incorporate any baffle step compensation in their crossovers.
Baffle step compensation is a technique used in speaker design to correct for the loss of bass frequencies that occurs when sound waves emitted from a speaker encounter the edge of the speaker's baffle or cabinet. It involves adjusting the speaker's frequency response to compensate for this loss, typically by boosting the bass frequencies.fab ... one day you can translate that for me as a pleb
For a speaker on a baffle the higher frequencies tend to radiate into half space( ie forward) low frequencies tend to radiate omnidirectionally ie into full space and can represent a -6 dB drop in level ( under normal circumstances of use ie not free air, matters such as room boundaries conspire to limit the amount of actual reduction to only a couple of dB- if at all)fab ... one day you can translate that for me as a pleb
For a speaker on a baffle the higher frequencies tend to radiate into half space( ie forward) low frequencies tent to radiate omnidirectionally ie into full space and can represent a -6 dB drop in level ( under normal circumstances of use ie not free air, matters such as room boundaries conspire to limit the amount of actual reduction to only a couple of dB- if at all)
The frequency at which a loudspeaker transitions from half to full space radiation is dictated by the width of the baffle.
True Audio TechTopics: Diffraction Loss
True Audio Tech Topics: Loudspeaker Diffraction Loss and Compensationtrueaudio.com
The narrower the baffle, the higher the frequency at which the transition from forward radiation to omnidirectional radiation occurs. So, in theory with all else being equal, the loss would be more noticeable in narrower Eatons with slightly more leanness in the lower midrange/upper bass region compared to a wider baffle Eaton. How audible this would be when the enclosures are placed against a wall I'm not sure, but wide-baffle, shallow enclosures have the added advantage of being able to have the baffle located closer to the wall than narrow-baffle, deep enclosures, which compounds the effect we're describing.To bring that to its logical conclusion, does that mean that narrower speakers with narrower baffles have lower frequency transition points? Or is it the other way around for wider speakers with wider baffles?
Specifically, would narrower Eatons have lower transition points than wider Eatons? Or is it the other way around?
The narrower the baffle, the higher the frequency at which the transition from forward radiation to omnidirectional radiation occurs. So, in theory with all else being equal, the loss would be more noticeable in narrower Eatons with slightly more leanness in the lower midrange/upper bass region compared to a wider baffle Eaton. How audible this would be when the enclosures are placed against a wall I'm not sure, but wide-baffle, shallow enclosures have the added advantage of being able to have the baffle located closer to the wall than narrow-baffle, deep enclosures, which compounds the effect we're describing.
Fantastic. I understand now. Thanks for posting the link Robert.Good explanation on baffle step from Peter Comeau in this interview.
Worth listening the whole thing but the relevant section starts at 10m in: