Bilavideo
Caution: Incomplete trades.
- Joined
- Feb 29, 2008
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I'm working on wooden shells for an SR60 mod but it seems to me that we may be barking up the wrong tree. When it comes to speaker shells, there seem to be three choices: (1) closed back; (2) open back; and (3) semi-open. Closed cans act like acoustic-suspension speakers, with everything sealed in airtight. This lets the back wave push the driver cone back into position. Such cans have the best slam, though they can also sound "canny."
Open cans go backless. This reduces back-wave resonance by allowing it to radiate freely, though such cans are not quite as loud since you're not getting any help from that back wave. Semi-open cans try to get the best of both worlds. They leave openings to allow a reduction in resonance. On the other hand, since bass slam is a welcome form of resonance, these cans use periodic obstructions to return some degree of the back wave to the listener. In their own, bass-reflex systems, which use a port to deliver some part of the back wave to the listener, are operating at the level of semi-open cans.
I'm a big fan of my Grados. No other headphone grabs HF energy and excitement quite like the Grados. I love the clarity and detail they provide. I also love the absence of that canny closed-can feel. But the higher up you go in the Grado product line, the larger investment in rear chambers. Depending on your wallet, these chambers can be small or large, plastic, aluminum, wood or a wood-aluminum hybrid. But what are you buying, beyond the larger, fancier, materials? I'm not knocking the workmanship or value of these shells. Instead, I'm wondering aloud about whether they represent a semi-open approach. If we're trying to listen to the driver, and only the driver, why should we care so much about what happens behind it? Aren't the front waves what really matter in an open can?
I've noticed, as I pare away the headphone shells, I have to turn my source unit's volume higher, which is indicative of a tighter focus on front waves. I've also noticed that the presentation becomes that much clearer and sharper in detail. I lose slam in the process, but that's precisely what happens when acoustic suspension is replaced by infinite baffle. The drop in resonance clarifies but also leaves the driver with less volume. If the answer has anything to do with providing the ears more isolation from the wave-canceling interactions with the front- and back-waves, why not build a bigger baffle between front and back waves?
If Grado can build a tube that extends backwards, channeling the back waves, it can also build laterally, to provide a real baffle between front and back. It seems to me that the primary reason to build a chimney or a cannon is to recycle back wave, making the headphone louder. But why use back waves when front waves are such a better choice?
Rather than supplement the master volume by recycling back-waves, maybe more thought should be given to capturing more front-wave action. This would certainly improve the quality of the bass received, making it tighter and purer. If the driver is the only part of the headphone that makes sound, it should be performing a solo. Anything else would just come across as a bad copy, a distortion, a coloration of the original recording. If there's a concern about dispersion, leaving the bass to engage in what is called the "baffle effect," bass radiating around the baffle, why not make the baffle wider? If we're going to build a shell, why not build it on the front of the headphone rather than the back?
Open cans go backless. This reduces back-wave resonance by allowing it to radiate freely, though such cans are not quite as loud since you're not getting any help from that back wave. Semi-open cans try to get the best of both worlds. They leave openings to allow a reduction in resonance. On the other hand, since bass slam is a welcome form of resonance, these cans use periodic obstructions to return some degree of the back wave to the listener. In their own, bass-reflex systems, which use a port to deliver some part of the back wave to the listener, are operating at the level of semi-open cans.
I'm a big fan of my Grados. No other headphone grabs HF energy and excitement quite like the Grados. I love the clarity and detail they provide. I also love the absence of that canny closed-can feel. But the higher up you go in the Grado product line, the larger investment in rear chambers. Depending on your wallet, these chambers can be small or large, plastic, aluminum, wood or a wood-aluminum hybrid. But what are you buying, beyond the larger, fancier, materials? I'm not knocking the workmanship or value of these shells. Instead, I'm wondering aloud about whether they represent a semi-open approach. If we're trying to listen to the driver, and only the driver, why should we care so much about what happens behind it? Aren't the front waves what really matter in an open can?
I've noticed, as I pare away the headphone shells, I have to turn my source unit's volume higher, which is indicative of a tighter focus on front waves. I've also noticed that the presentation becomes that much clearer and sharper in detail. I lose slam in the process, but that's precisely what happens when acoustic suspension is replaced by infinite baffle. The drop in resonance clarifies but also leaves the driver with less volume. If the answer has anything to do with providing the ears more isolation from the wave-canceling interactions with the front- and back-waves, why not build a bigger baffle between front and back waves?
If Grado can build a tube that extends backwards, channeling the back waves, it can also build laterally, to provide a real baffle between front and back. It seems to me that the primary reason to build a chimney or a cannon is to recycle back wave, making the headphone louder. But why use back waves when front waves are such a better choice?
Rather than supplement the master volume by recycling back-waves, maybe more thought should be given to capturing more front-wave action. This would certainly improve the quality of the bass received, making it tighter and purer. If the driver is the only part of the headphone that makes sound, it should be performing a solo. Anything else would just come across as a bad copy, a distortion, a coloration of the original recording. If there's a concern about dispersion, leaving the bass to engage in what is called the "baffle effect," bass radiating around the baffle, why not make the baffle wider? If we're going to build a shell, why not build it on the front of the headphone rather than the back?
