Thanks very much Peter! I intended to keep the height and width dimensions identical for the baffle face but thought to increase the depth of the face to reduce vibration and thought it might be good to shape the front along the Sa--n2 lines? I really had no thought of changing the overall box design, internal volume or stuffing material/quantity & shape -- and I wouldn't dream of changing the crossover. But I also had no idea of the relationship of the crossover to the dimensions and I appreciate your heads up. Very thoughtful & generous of you!
Basically I am just a listener hoping to reduce the gross deficiencies of the lightweight box and its vibrations. I hadn't thought beyond using laminated hardboard and MDF and painting the box black like the current boxes. Maple hardwood does sound like a nice step up. |
Thanks Zd. I think the screws on 'virtually' all cabinets loosen over time due to the laws of physics. I am a fastidious about maintaining screw tightness on my cabinets and drivers as I also own a pair of heavily modified JBL 250Ti"s which have a 14 inch bass driver with an ~ 22 lb magnet that has real propulsive force! I'm with you that loose drivers means loose sound. (I am very fussy about stringed classical instruments clarity). On my B&W Concept 90 CM1's one must tighten the entire, unique, one piece baffle to the box as well as the dome tweeter to the baffle. Both loosen even though obviously they're not played that loud. (Yes I take off the baffle from time to time to check the 4" driver.) |
Peter, thanks for the heads up on breathing room for the driver. I really appreciate the very revealing photos you attached to your post! |
S7horton, will do today thanks. |
Thanks Zd & Rodman. I'll look into Corian. |
Onhwy, there is absolutely no question that 'cabinet resonances', particularly those on the front baffle, reduce the clarity, dynamics and nuance of the sound due to the basic laws of physics.
I think ROCKPORT TECHNOLOGY website addresses this quite well. In a nutshell the drivers create sound by vibrating. For the sound to be 'just the sound created by the driver' there must be zero other vibrations influencing it. I understand your question as indeed different listeners have different "tastes" in both music and sound--so eliminating vibrations may not make the sound "better" to all; but definitely "different". |
Daedulus, Rodman makes a valid and very interesting point. Serious woodworkers will know it "wood :-) " be virtually impossible for cabinets of different wood species to react the same to the drivers so they 'wood' all sound different! |
Thanks Rodman, very interesting about Corian. I like the idea of a curved baffleboard -but-Peter of PBN mentioned the crossover is designed around the precise dimensions of the baffle and I wonder if that means it should also remain flat and square? It's very good to hear it can be built up. |
How about 3/4 or 1&1/2 inch black granite countertop green glued onto 3 inches thickness of MDF? Very non-resonant? |
Rh I had no idea the CM1 woofer could bottom out. I have always maintained screw torque but never driven the speakers very hard. But even so the cabinets are nowhere near inert. (However I drive them with a 200 watt Spectral amp with ample current; lots of clean power available for dynamics-but even so these little B&W's don't have good dynamics.) Making the baffle inert will improve dynamics considerably. |
Rh, would you like to sell your CM2's? I don't see them in your
system. |
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Thanks Vapor. I have noticed some rosewoods have very high figures for density and hardness; they're sometimes condidered ironwood.I didn't know if the output from the relatively low output B&W would be strong enough to excite granite? |
Unsound, I meant identical to the original speaker face- not- width & height identical; thanks for your comment. |
That's interesting Tim. It invites thinking of other damping materials to put in the concrete. Do you think styrofoam has enough mass to absorb vibration? Maybe lead powder? Lead is not toxic sitting as metal. In fact the way Wilson used it in their speakers would do no damage to listeners either. It was encased in the x,y or z material. There must be other materials as well. My thinking is the styrofoam would virtually act as an air bubble. What are your thoughts? |
Hi Peter. The new epoxy technology is changing decorative concrete cast planters, garbage receptacles, etc. Didn't Thiel use concrete baffles? |
Hello PBNaudio, your input much appreciated. I'm just getting back to this project for 'the perfect cabinet" for the B&W drivers presently in the synthetic cabinets of the B&W Concept 90 CM1s (which vibrate 'nicely' with very little energy input ;-) .
I now have someone who is happy to do the cabinet work as an interesting joint project and has the necessary woodworking tools and skills; as he would like to make speakers for himself from a kit. I enjoy music through the CM1's (with 25 lbs of lead on them) so have time to do what I want. I like to think there may be a better way to provide 'breathing room" behind the cones than simply using a conical opening-which I appreciate as practical- so I want to evaluate more complex ideas. Any suggestions for something more 'extreme'? I'm not the least concerned with diminishing returns-simply going all out--without wild expense. What do you think of a "variably" slotted opening instead of straight cone? |
Hello S7horton. I've been on hold with this (I think my massive "myocardial infarction" had something to do with that :-) ).
Ready to get back to it now. Looking to go all out for the construction of these little cabinets. I'm considering all aspects of interior cabinet design-to kill standing waves & resonance. I'll be in touch thanks. |
Is there a benefit to adding surface area to a speaker? |
Jonnk. My first idea was to respond "fribbett" as Johnny English said. However, I thought I'd better look up CHOBHAM --and WOW -- what a revelation. I am looking into it. Do you have some available and the blades I,d need to cut it??? ;-)) Where the heck did your knowledge come from? I,d bet not one in a million knows what you,ve described.. |
I'm going to research specs on materials- Chouhan , ceramic, aluminum,steel plate, exotic ironwoods, granite , artificial granite and other new countertop materials, maple, South American cherry woods for the hardness,density and vibration attenuation properties. Will report my findings. Any other materials I should consider? How is the energy disappated with all metal Magico or similar systems? I'm inclined towards Rockports multi-material designs as intellectually appealing and fully expect some combination to be the best bet. Wilson was using lead pads within their walls for mass and damping qualities. Cost and workability factors will be interesting. |
Associated with baffle material is treatment for the front surface. I notice Rockport designs in felt faces and Wilson has used felt a very long time. YG and Magico don't bother. ?? |
