Hi all,
I'm experimenting with methods of de-coupling the woofer in part of a 2-way monitor speaker. Woofer driver being used is the Satori MW16. I've thought of some different methods from research and came up with the following conclusions:
-Mounting the drive unit on rubber well nuts (isolation grommets) similar to the TAD high end speakers (attached below) works well for isolating the baskets and lowering unpredictable magnet movement down to the upper bass frequencies (~200-300hz, depends on specific driver). This is good for a midrange speaker that will be crossed over around that point, however at frequencies below that, when used as a woofer, the magnet exhibits greater movement than if it was rigidly mounted to the enclosure, diminishing the transient response of bass frequencies as this is a loss of energy.
-Rigidly couple the magnet of the speaker to the inner brace of the enclosure and isolate the driver basket from the front baffle. This, in theory, should mean that no part of the resonant basket is touching the enclosure, yet the driver remains steady as its coupled by the magnet directly to the enclosure. There can then be a ring of rubber, foam, etc gasket to ensure air tightness.
-Combine both of these solutions. By combining both solutions, the speaker can still be "bolted" to the baffle using well nuts, so that it is stable, then further mounted directly using the method above.
One small issue arises in my speaker, is that the front baffle is angled back at 7 degrees for time alignment, and the magnet shape and design of the satori speakers are less then ideal for this type of mounting, therefor asking if anyone has some ideas to throw around on possible solutions or experimentation of their own.
Kaden
I'm experimenting with methods of de-coupling the woofer in part of a 2-way monitor speaker. Woofer driver being used is the Satori MW16. I've thought of some different methods from research and came up with the following conclusions:
-Mounting the drive unit on rubber well nuts (isolation grommets) similar to the TAD high end speakers (attached below) works well for isolating the baskets and lowering unpredictable magnet movement down to the upper bass frequencies (~200-300hz, depends on specific driver). This is good for a midrange speaker that will be crossed over around that point, however at frequencies below that, when used as a woofer, the magnet exhibits greater movement than if it was rigidly mounted to the enclosure, diminishing the transient response of bass frequencies as this is a loss of energy.
-Rigidly couple the magnet of the speaker to the inner brace of the enclosure and isolate the driver basket from the front baffle. This, in theory, should mean that no part of the resonant basket is touching the enclosure, yet the driver remains steady as its coupled by the magnet directly to the enclosure. There can then be a ring of rubber, foam, etc gasket to ensure air tightness.
-Combine both of these solutions. By combining both solutions, the speaker can still be "bolted" to the baffle using well nuts, so that it is stable, then further mounted directly using the method above.
One small issue arises in my speaker, is that the front baffle is angled back at 7 degrees for time alignment, and the magnet shape and design of the satori speakers are less then ideal for this type of mounting, therefor asking if anyone has some ideas to throw around on possible solutions or experimentation of their own.
Kaden
Is there any evidence that the magnet is less energetic than the periphery of the front of the drive unit? If not, you’re as likely to transfer more energy into the enclosure using your proposed method than by mounting the driver conventionally. The best way to reduce the amount of energy being transferred to the enclosure is to use a 12mm thick baffle which is lightly screwed to the enclosure. Also, don’t over tighten the driver mounting screws. The screws need to be just tight enough to prevent secondary vibrations between the surfaces. Anything any tighter will make the transfer of energy more efficient.
A brace with circular mid section, with a hole in it (sufficiently large , even chamfer it). for the vent obviously that the woofer rests against. Use a harder damping material more similar to rubber, and lightly compress the woofer against it with mounting.
Have not seen all of the SB's in person. But that lower basket ring around the magnet serves no structural purpose on the ones i have encountered, just cosmetical, and the backside goes into the box. a magnet clamp solution is possible to make.
Let me refer you to the German DIY-Hifi-Forum (use a translation programme) and there to a thread by Christoph Gebhard in which he develops a four-way loudspeaker. The thread is definitely worth reading in full.
Be that as it may: From post #65 onwards, he describes how he mounts the midrange and tweeter with vibration dampers in the cabinet.
A few posts later, he also analysed the effect of this measure using measurement technology.
Be that as it may: From post #65 onwards, he describes how he mounts the midrange and tweeter with vibration dampers in the cabinet.
A few posts later, he also analysed the effect of this measure using measurement technology.
Mounting via the magnet is a good idea if you can do it effectively without restricting the air too much. It's not clear to me from the image how you intend to achieve this?
If you mount via the magnet and passively isolate the frame from the baffle (e.g. soft grommets) then effectively no work will be done on the baffle which is what you want. Vibration will still be transferred to the cabinet via the magnet mount but if it is significantly stiffer than a baffle mount then the amount of work done on the cabinet will be significantly less (rate of work done is the product of velocity and force and a stiff mounting reduces the velocity). If you want to go a step further then attach the woofer to a heavy structure inside the cabinet that is not attached to the external cabinet. Likely an unnecessary step if the magnet mount is performed effectively enough for the cabinet vibration at woofer frequencies to be reduced to inaudible levels.
If you mount via the magnet and passively isolate the frame from the baffle (e.g. soft grommets) then effectively no work will be done on the baffle which is what you want. Vibration will still be transferred to the cabinet via the magnet mount but if it is significantly stiffer than a baffle mount then the amount of work done on the cabinet will be significantly less (rate of work done is the product of velocity and force and a stiff mounting reduces the velocity). If you want to go a step further then attach the woofer to a heavy structure inside the cabinet that is not attached to the external cabinet. Likely an unnecessary step if the magnet mount is performed effectively enough for the cabinet vibration at woofer frequencies to be reduced to inaudible levels.