OT Rubber mounting the speaker

I was thinking the other day as I listened to my speakers resonate my cabinets that maybe if the speaker was somehow connected to the cabinet using a piece of rubber...say 3/8 thick industrial stuff with the white cord running through it. if this would make much of a difference? I googled the idea and found something but I didn't think to bookmark it...kinda sounded like some German high end speaker maker was doing it... You would think it would cut down a lot of the coloration. My 604 C has no gasket and mounts directly frame to baffle while the 604 E has a gasket but I can't imagine it does much since it's screwed down tight to the baffle anyways. What are your thoughts on this idea? :o

My .02 would be that the preferred remedy would be to damp/deaden the cabinet via bracing or other methods.

I think this is where I got it from... Down towards the bottom of the page.
http://www.linkwitzlab.com/frontiers_2.htm

You don't need anywhere near 3/8 inch.

There are rubber membrane rolls for roofing often about 1/16 inch or so.

http://www.rubber4roofs.co.uk/EPDM-R...Shedcover-EPDM

I used to stop by roofing places and offer a few bucks for scraps...they throw away pieces large enough for us.

Thanks Old Guy, Originally I was picturing mounting the basket of the speaker to the baffle with rubber I'm not sure I would want to risk hanging a 40lb duplex with a 1/16 thick piece of rubber but if your talking the mount the speaker by grabbing the magnet then yes 1/16th would be fine. Which after reading the link I posted I see they were saying mount it by the magnet not the basket. :2thumbsup:

I use the rubber between the frame and baffle. I use an adequate baffle the rubber is to seal,

As a general rule, about the last thing you want to do with a LF reproducer is 'float' it. The goal is to provide the most stable 'platform' practical for it to do its 'work' efficiently, so ideally it isn't attached to the cab in any way and its design is such that it has no self induced vibrations in its pass-band.

If one looks carefully at an early WE open baffle 'sub' used under the large 15a horns you'll notice that the massive LF driver(s) snuggle up to the baffle, but are not actually bolted to it, instead bolted to a separate, rigid/massive platform or floor.

Later, no doubt to cut cost, etc., for mass production, surround gaskets of the right density to damp any driver induced resonances were developed to allow rigid mounting to a sufficiently rigid/massive baffle.

WRT your 604C, I've never seen a wide BW Altec driver with no mounting gasket, but again, the driver/cab is a system, so if it didn't come from the factory with a gasket, then apparently the assumption was that it would only be used in an Altec approved cab that had taken this into account WRT material, assembly choices.

Note that the gasket design is based on a given clamping pressure, so for max efficiency the specified hardware must be torqued to spec which for most (all?) prosound drivers which I lump Altec into would be based on standard bolt size/thread torque charts which typically is much lower than the average person would hand tighten to.

All that said, if the driver has a high Qts (> ~0.7), then its mounting should be lossy, increasing with increasing Qts to mechanically damp it, effectively lowering its Qts and why those old Motorola consoles with the woofers mounted in individual Styrofoam 'cabs' sounded so good, yet when swapped into a regular cab rang like a 'ten penny nail struck with a ball-peen hammer'.

GM

Bowtie & GM have hit it right.

Idealy speaking, the driver mounting should be as rigid as possible. The box contact with floor etc also. We want all the impulses reproduced perfectly. No shock absorber theory here. The worst sufferers will be the low Qts drivers (namely Altecs). We will end up with non linear transients, especially in the lows.

We talk of sand filled cabs, to bring mass/rigidity into the system. Now the drivers will swing on their own cushions ?

Now having said all that, it is also true that every coupling has a resonance f, and it may be used to some advantage in eliminating known (troublesome ?) areas. But as I see it, it is either a heavily compromised design or a very evolved one. For the later case, it will be a very very complicated design.

Aditya

Nice to finally see mention of Siegfried Linkwitz on this forum -- never imagined that it would ever happen.

His recommendation of magnet-mounting applies to the midrange driver of the Orion loudspeaker system; it is intended to prevent driver frame/magnet resonances being transmitted to the baffle. It applies to the midrange driver of the Orion, not the LF drivers. Btw, Pioneer/TAD also made similar recommendations for MF cone drivers as well.

While ideal, it is not feasible for heavy LF drivers so a thicker baffle or extensive baffle panel bracing to push the frequency of panel vibration upwards where it is much smaller in magnitude is the best compromise.

BobR

Yes!!! Siegfried Linkwitz was the name I was reading about!! it kinda sounds German....Is this the same thing as what they did in that 6 moons article with the 604's? I remember they had some kind of clamping system on the magnet part of the speaker although if I remember correctly the speaker was mounted to the baffle too... I think it's all starting to make sense now.....your gonna get panel resonance no matter what. And you want to drive up the resonance frequency because it's less noticeable ( it gets harder to hear the resonances at higher frequencies) and to raise the resonance of course you would want stiffer just like the tighter the guitar string the higher it rings at. so Because I'm hearing what sounds like the box making the sound instead of the speaker is because the cab frequency is to low? It happens mostly when people are talking on movies.
This place has more useful knowledge that the encyclopedia Britannica. Thanks again guys for the wisdom.