I already wrote that. But noone so far mentioned it before I did.
You did not say about floor vibrations. If you got distortion because of vibrations of the enclosure, then it will get worse. Build a stiffer, heavier, generally mechanical better box with stiffening. Or a sandwich material with very fine sand in it (except the bottom panel).
Not concerned about cabinet vibrations ... it is the vibrations between speaker and floor I am concerned with.
I'd imagine if you had back to back bass drivers and a concrete floor, it wouldn't make a lick of difference - unless cabinet vibrations were being damped by their connection with the floor, however if you had open baffles with big bass drivers using lots of excursion to make up for open baffle losses, and a wooden floor bungee suspension would be a big improvement. I think someone mounted electrostatics high up on their ceiling, but that was more with freeing up floor space ( UK home ).
Ok plan B. Spring-dampers supporting the speaker in each direction of movement. One end of them can be attached to the floor, or to a sub-frame attached to the floor.
Flaxxer,
The bungees will continue to stretch, and the speakers will be on the floor before long. Until they drop, the bungees would eliminate most mechanical transmission.
If the bass driver has high moving mass, at high excursion, a light weight cabinet will rock, which could result in a small reduction of output and some small amount of Doppler/IM distortion. Those effects would probably far less than the mechanical transmission problem you seem to want to avoid.
In a sense that's the same. If the cabinet doesn't vibrate, the floor doesn't either.
Fired red clay simply will not vibrate at the frequencies of interest. I know because I virtually eliminated transfer to the floor by my subs this way. 2" thick red clay ceramic patio stone with a 1" thick floor polishing fiber scratch pad between it and the sub. Zero transfer to the floor.
Each spring-damper will have its own resonance frequency. The problem of that system is the uneven forces. Be it by length because you need the speakers on a certain height, you can't have them at a symmetrical setup. And the gravity dictates different spring force/tension aswell. since you can't put a mounting rig in front of it because of the sound (can be critical in the upper range, low frequency don't mind at all) and usability and look of the whole room, that's not an option. You'd rather have a multitude of different resonance frequencies which can result in a tumble motion, which can result in a modulation of the treble because of directivity and angle and doppler effect (even at very low changes in angles and distance), which is very annoying and disturbing. That makes the problem a ton more complext and a nightmare to correct because of the immense interaction to each other.
While the approach to add 'more benefits' can be very attractive and seemingly logical, it often expedites the drawbacks by a whole other magnitude. It could be done and optimized, the effort, time and the possibility to having no acceptable result and immense space that would require to realize makes that concept very unattractive. I mean, instead of using maybe 1m² for each speaker placement (so around 2m² for a stereo setup) you'd sacrifice around 10m²+ for such a setup. I don't know who can accept that much space in the listening room except maybe Hugh Hefner and he's dead. 😉 😛
I very much doubt the vibrations of the floor are the main problem, I suspect the room modes excite the adjacent rooms/apartments/walls/floor/ceiling are the major underlying problems. For that a double bass array could be the better improvement. I can't tell because there's no information on the room(s) or why it's an issue anyway. Just posting a vague, general problem/issue does not give anything else than just a vague, general solution. Sounds logical but while concentrating on a single aspect and blacking out other parts of it might get an improvement or even a complete solution to that single aspect but lacks of other aspects that still apply and still co-interact on the other (tethered) physical characteristics which makes the whole compromise so much worse it's not in the least acceptable.
Unless the forum knows which problem exists in the first place, the forum can't provide any adequate solution. The fewer input informations, the fewer output informations. Please don't misunderstand this, I'm not mad but the ammount of interpolation of the missing informations is here on a level which makes a real-world solution practically impossible.
I can only fully agree on that. Excellent summary and probably the best interpolation of the missing informations, that's just point on! Given more informations, there might be a much better (and simplier) and effective approach to the problem and much less requirements to solve a single-cause proposed resolution which fails to adress the actual issue.
I don't want to tell what's not realistically doable or what's not a solution in this case which is actually a very good idea in a different situation but it's not in this case. I want to be constructive but with the missing informations it's actually really hard to suggest anything because noone got the whole picture. I've made several assumptions, which might or might not apply but everyone on this thread got the same problem. Please tell what's the problem in the first place and you'll very, very likely get a much better and easier, cheap and more effective solution to your problem.
It's not my intention to offend anybody but unless there are more informations about this case, nobody can actually help.
Side note: I'm not sober atm (well, not at all), if something offends anyone, please notify a mod to delete that part or the whole post. *sigh*
Uhm, if it's not burnt, it loses the absorption properties when drying out. If it's burnt, it loses it completely.
I'd say we were being hypothetical.. but there are solutions to the problems you mention.
However the idea of a box that doesn't move is attractive because it offers to fix the problem at its source and because it is doable. Start with opposed woofers.. this is the biggest first step in stopping the cone pushing against the whole cabinet. Next comes preventing the bottom panel from flexing against the floor.
However the idea of a box that doesn't move is attractive because it offers to fix the problem at its source and because it is doable. Start with opposed woofers.. this is the biggest first step in stopping the cone pushing against the whole cabinet. Next comes preventing the bottom panel from flexing against the floor.
Siegfried Linkwitz had this kind of solution at his home a long time ago.
http://www.linkwitzlab.com/images/photos/sb2-12.jpg
http://www.linkwitzlab.com/images/photos/sb2-12.jpg
Bungee cords are only one possibility. But they can be easily adjusted for height if they stretch. Nothing some brass pulleys couldn't fix! LOL
I have no agenda here, but to learn. I am starting with the assumption this should effectively work.
We can take all of these other variables out even ... let's say these speakers are on a nice wooden hardwood deck with seating area, lifted off the ground outside even. But there is a LARGE steel girder running above the speakers about 10 feet up. IF you suspended them as we are speaking, with the bottoms only a couple of inches off the ground ....
I have no agenda here, but to learn. I am starting with the assumption this should effectively work.
We can take all of these other variables out even ... let's say these speakers are on a nice wooden hardwood deck with seating area, lifted off the ground outside even. But there is a LARGE steel girder running above the speakers about 10 feet up. IF you suspended them as we are speaking, with the bottoms only a couple of inches off the ground ....
I think by far the worst culprits are vertical " firing " bass drivers, in my latest speakers I used compression coil springs and foam ( to hold the springs in place during assembly/disassembly, seal the gap and add dampening ), to separate two sections of the cabinet - this also stops vibrations from the driver spreading throughout the whole thing.
What about fitting a lifting eye to the bottom of some speakers and suspending them upside down ( with the tweeter still at ear height ) ?
I remember reading about Matra F1 teem dyno testing a V12, they decided to bolt it rigidly to the very heavy test bed, and they instantly lost about 15 HP, even though a F1 V 12 is going to have good balancing, the increase in friction due to the ridged mounting to a mass shows how much forces can increase if you connect a vibration to something solid - hence the prevalence of light none ridged speakers like the BBC Ls 35a.
I think that there is a movement in recording studios of sprung/damped speaker stands.
^it depends from acoustician and solutions choosen to implement the room but yes it is used.
At 45" you can spot arount the ATC the system T. Jouanjean use atm ( and the decoupling used for the whole control room at 2mn):
Noisia Studio Tour | Razer Music - video Dailymotion
I've seen other things done. Craziest was to have an independant ground slab for frontwall not connected to anything ( any walls) within the room.
At 45" you can spot arount the ATC the system T. Jouanjean use atm ( and the decoupling used for the whole control room at 2mn):
Noisia Studio Tour | Razer Music - video Dailymotion
I've seen other things done. Craziest was to have an independant ground slab for frontwall not connected to anything ( any walls) within the room.
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Like I quoted 🙄, clay. It dries out and hardens up a lot. Not as much as sintering/burning it but it will not stay elastic at all!
For that to happen the box is vibrating and transferring energy to the floor. If it is mechanical thru the box you should fix thebox first. If it is airapace excitation there is little you can do wrt mounting the box.
dave
I did not use bungees i used chains. You want a very low frequency coupling point and bungees are likely create one far up from ideal.
dave
Titghtly couple th edrivers. Box vibrational-load is dramatically decreases. Very much so Active Reactive Force Cancelation (ARFC, wonder if that TLA will catch?).
dave
Vibrations come from the floor up. From the air itself. From the earth itself. From everything in nature. For the last time, there is NOTHING wrong with my enclosures. They probably vibrate less than 95% of the ones most people make. I go to obsessive levels.
This is NOT the topic I am interested in. But thanks.
PS: Simple physics ...cables or chains have a higher resonant freq than bungees. Always.