Second question on here. The amount of knowledge on here is very impressive.
So… I’ve designed and built a few speakers. The way that I “tuned” the overall sound was through passive crossovers to each component, enclosure size, and whether or not the enclosure included a port and the length of the port. With that said, how do manufacturers “tune” headphones?
From some of the videos I’ve seen about the Blon 20, Monolith M570, Sendy Aiva, and Sivga P-II all share the same driver but each manufacturer “tuned” them a bit differently.
I was just curious as how that’s done from a physical standpoint. If the shape and enclosure size changes I get it. But all other things created equal, how is it done?
About how you described tuning a speaker:
Open or close openings, put baffles or padding in place, put denser foam in the pads, put foam disks of various thickness in front of the driver, etc.
With stiffer plastics, manufacturers may have to put elements (basically a spring made from plastic) in that can flex to work arround the resonant frequency of the earcup.
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Thanks so much. Very straightforward. I should have thought about all the T50rp mods and what they do to answer my own question. Greatly appreciated.
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This reply is to both you and @randymessman. I’m not certain that the process is the same. Speaker tuning as Randy described is a traditional method of solving the speaker as an electrical equivalent circuit, as written about by Butterworth. Lots of literature on this from the 1960s, with a sealed box being a 4th order and a ported one a 6th order Butterworth design.
https://www.google.com/url?sa=t&rct=j&q=&esrc=s&source=web&cd=&ved=2ahUKEwi4jOaX0u3pAhUbmXIEHU2AAHgQFjAHegQIEhAB&url=https%3A%2F%2Fen.wikibooks.org%2Fwiki%2FEngineering_Acoustics%2FBass_Reflex_Enclosure_Design&usg=AOvVaw3az8pVvrtSuCJ2FGBwMe3L
This basic knowledge has been tweaked considerably with knowledge of damping materials, design of interior barrels (transmission line, or the weight of air in the port of a bass-reflex design).
From what I’ve read about IEMs, there is a lot about transmission lines - from the driver to the eardrum, and on higher end IEMs some on crossovers, selection of drivers (just like speakers), and possibly more on geometry. There are some people on here with much deeper knowledge.
I think the key difference is that the speaker will be pushing sound into a large room, and the IEM is essentially a closed volume from the IEM to eardrum.
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That one fair reason many are skeptic with multi BA headphones. There are like 4 Single BA iems that can do 17 ~ 19KHz with the thd being <0.55%. In my 2nd case the ER3/ER4 respond well to boosting the bass by EQ. The SPL levels & deep fit on most 1 BA IEM’s is low enough that a 5mm driver is enough. These days I’m sure Ety could force knowles to make a Full range BA do 20 - 20,000Hz.
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