According to Joseph D'Appolito ( and i quote ): "The grille is there only for cosmetic effect and to protect the drivers from prying fingers. The perfect grille is still the Holy Grail of speaker design". The article that he stated this in shows the performance of a speaker with and without the grille on. With the grille off, the response is very flat overall and almost resembles a perfectly straight line across the band. Simply adding the grille caused an increased variation of +1 and -3 dB's. That's a variance of 4 dB's total and a graph that looks choppy as can be above 1.5 Khz.
With that in mind, I have yet to see a grille that didn't:
1) create upper midrange / high frequency irregularities. This is due to what is known as "diffraction" and "nearfield reflections".
2) soften and slow high frequency transients. This is due to non-linear absorption characteristics, with higher absorption taking place as frequency rises.
Some grille's are obviously worse than others, depending on the materials used and their support structures. Since there is no such thing as "acoustically transparent" material, all grille's will alter the sound to some ( usually quite measurable ) extent. It is up to the end user to decide whether or not the grille's are beneficial or detrimental to performance within the confines of their system and personal preferences.
Since we are on the subject, metal "cages", "screens" or "lenses" over tweeters or mids can also create massive ringing and glare. I have yet to hear a speaker that didn't sound smoother after the "cage" was removed. Obviously, this WILL affect their radiation patterns also. Whether or not you want to do this with "little ones" around may be a different story though.
As far as i know, the folks that have done the most research in terms of grille effects were Acoustic Research ( AR ) and John Dunlavy. They both came out with very similar findings and designs at about the same time ( late 70's ).
Personally, i typically like to leave the grille's off when listening. If a recording is very bright, glaring or forward, putting the grille's back on can help tame this, but typically with other noticeable side effects. As such, i typically just deal with it. Sean
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With that in mind, I have yet to see a grille that didn't:
1) create upper midrange / high frequency irregularities. This is due to what is known as "diffraction" and "nearfield reflections".
2) soften and slow high frequency transients. This is due to non-linear absorption characteristics, with higher absorption taking place as frequency rises.
Some grille's are obviously worse than others, depending on the materials used and their support structures. Since there is no such thing as "acoustically transparent" material, all grille's will alter the sound to some ( usually quite measurable ) extent. It is up to the end user to decide whether or not the grille's are beneficial or detrimental to performance within the confines of their system and personal preferences.
Since we are on the subject, metal "cages", "screens" or "lenses" over tweeters or mids can also create massive ringing and glare. I have yet to hear a speaker that didn't sound smoother after the "cage" was removed. Obviously, this WILL affect their radiation patterns also. Whether or not you want to do this with "little ones" around may be a different story though.
As far as i know, the folks that have done the most research in terms of grille effects were Acoustic Research ( AR ) and John Dunlavy. They both came out with very similar findings and designs at about the same time ( late 70's ).
Personally, i typically like to leave the grille's off when listening. If a recording is very bright, glaring or forward, putting the grille's back on can help tame this, but typically with other noticeable side effects. As such, i typically just deal with it. Sean
>