scooter wrote:

If you are going to be sanding in your living quarters, I strongly recommend that you: 1) cover the ENTIRE rug in the room; you will never get all of the dust out of the rug and will ruin most any home vacuum cleaner (alternatively you can just purchase a new rug when you finish) 2) seal off all doors and closets with polyethylene tarps and tape 3) seal all of your electronics, CDs and records likewise Don't be duped into avoiding this prep work. These steps may seem like a trivial pain in the neck but trust me from experience, the sawdust is incredibly difficult and time consuming to remove. Else you will find sawdust in the refrigerator, the freezer, your bed, your library. . .

Romy the Cat wrote:

One of the emails that I receive is very interesting. The author warns:   “...when experimenting with throaths I found that if the compression is big, near 2 or higher you get some big, smooth, unfocused aqualung sound. You are never scared at listening to that sound, like being on some downers at the concert under the water. The same was true with compression drivers ( 2440 ) when experimenting with phase plugs and listening without one, or with pre WW2 WE type ( or quasi modern japanese renessance ).”   The observation is correct. Most of the bass horns that I head have that unfocused aqualung sound; I usually call it “sewer pipe sound”. I certainly do not want my horn to sound this way and I have my own theory why the most of the bass horns out there sound as poor as they are. I however never consider that a guilty party might be the compression ratio.  I personally feel that a compression is irrelevant if the rest of the operation parameters of the driver and horns are taken care with respect to the given compression. I might be wrong but it is my position. A compression itself does not ruin sound the specific design decisions that can’t work properly with a given compression will most certainly ruin sound. So, even the warring is reasonable then I think the causality of the effect is incorrect. If I am wrong and if compression is devastating for bass then… this is why I am making the backs chamber in a way that the drivers mish be changed … Still, I hope that I will not have a need to do it.

Romy the Cat wrote:

The rest of the sending in the living room is not a big deal.

Romy the Cat wrote:

http://www.rent1.com/lifts.html

I still contemplate if I need one, two or three of the lifts. No matter what I think it will be manageable to list it up to the 12-13 feet that I need. Then I think the problem will take place. Those lift are stable one for vertical pressure but when the horns will be 12 feet in air we would need to slide them toward hosting the whole in the wall. The sliding is not a problem: we will use Come-Along winches, hopeful we will find a thing to tight it to in the frame. The problem that I see is how to martin the 12 feet elation if the top of the load will be sliding – I am afraid that my lifts will roll over.

So, probably some kind of rolling devise need to be figured out that will be locked during elevation but then they will let the horn get loose in horizontal plane after the horns are 12 feet up. At this point I do not know how to do it. To insult the injury my carpenter insets that the horn need to be slide into the hole at a precise angle as he need certain key surfaces of the horn to touch the certain key surfaces of the attic frame. He insists that we have no more than ½ inch clearance but only if the horn will be advanced angled (back chamber up and mouth down).

I did prose to oil up the attic hole, elevate the horn, tilt the lifts and throw it into the hole. It might bring my house down but it will do at least a great YouTube video…

From your recent posts it may be that you are already thinking along these lines but let me suggest an approach to the horn positioning anyway.

I don’t think it is either necessary or desirable to vertically lift the full weight of each horn and then move the horn and lifting apparatus horizontally to place the horn in the attic.

Further, I doubt if the horn is structurally strong enough to be unsupported during this lifting/positioning process without risking joint damage so some sort of heavy-duty support on which the entire horn rests would be in order. This support can act as a ramp/slide base.

I would use a three-step process:

1- The Easy Lift
First lift the lighter throat end of the horn/ramp system to the attic – or preferably to a strong temporary structure built from the main floor to the attic floor and right against the wall (something like your harness illustrated in post #250 but capable of supporting serious weight). The end of the ramp should be attached so it can pivot. Of course the horn is secured from moving on the ramp during this phase. The bulk of the weight remains on the floor.

2- The Heavy Lift
Then use your lifting device to lift the heavy mouth-end of the horn/ramp possibly high enough so that the horn/ramp is horizontal. You may need some tilt for positioning purposes. The pivoted end will bear more of the weight as the heavy end is lifted making for a far more stable and easier lift.

3- The Slide
Finally winch the horn into position. The horn assembly should be on skids or casters with the restraining structure that was used during lifting removed.

If the lifting mechanism becomes unstable before the full horizontal position is reached the horn might still be winched partially into position as any tilt from the ramp gives some mechanical advantage of an inclined plane to the vertical movement. As more of the horn enters the attic lifting the heavy end should become easier.

As Paul has previously advised, caution suggests additional shoring perhaps with screw jacks or scaffolding or heavy-duty lumber during the intermediate phases and of course during the final sliding and positioning.

I would also use some screw jacks to support the attic during this installation as the weight will be unevenly borne during the various phases.

All of this assumes that the hiring of insured professionals, such as piano movers, is not feasible.

Good luck,
Robert

noviygera wrote:

I feel that the best candidates are metal springs. 1. They won't compress or deteriorate quickly. 2. They work good in the used freq. range. 3. Easy to replace. Easy to tune by adding or removing springs. 4. Easy to float the entire horn by sandwiching it in springs from every direction.

Markus wrote:

Make a cradle for the horn and suspend it on belts, the kind used for European roller shutters like this

manisandher wrote:

One idea would be to use a number of inner tubes from tyres (tires). Townshend uses a 'wheelbarrow' tyre for his 'seismic' sinks and stands...