Wednesday

The big lift

*
Getting the 140 lb manifold indoors and up the 60 degree stairs was interesting. I had a block and tackle set up for the lift but it had eaten up all the distance between the triple pulley blocks before the tension was taken up. So I grabbed the loop of rope which I had passed through the top driver cut-outs and lifted it up the stairs bodily with one hand. My wife was down below pushing for all she was worth despite her 5'1" and seven stone stature. We are both past our sixtieth birthday but remain fit thanks to constant physical activity and a healthy diet.

Here's the manifold waiting to be pushed on a sack truck to the house steps. After that it was a matter of walking it up some 2 x 4s into the entrance hall and along to the bottom of the stairs. This bit was easy enough but then it required a 90 degree roll to get it on its back up the steep and narrow stairs of our old cottage. Some large cardboard packaging was quickly tied to the huge box to protect the black ash finish.

Once upstairs I walked the manifold into the IB enclosure and pushed it straight into the empty space between the wall studs. Then I spent some time lifting and lowering it on various wooden blocks using a batten lever as I searched for the optimum height. In the end the sloping wall would not allow a full exposure of the manifold mouth and I lost 4" in all over the full potential height. A couple of hours later the manifold had been screwed to the wall studs and I had closed off the various empty spaces above and below the manifold with large bits of solid timber. Still some work to do tidying up the wall on both sides.

Manifold in place but no drivers yet.

The view of the manifold, with the drivers in place, seen through the old glazed doors from the hot seat

The view straight into the manifold with all drivers in place.


Here's comparison between the old (right) and new AEIB15 drivers.

Each vertical set of four drivers was wired in series-parallel using lighting flex to see if it had been worth all the effort. I checked the DC resistance of each set with a DMM to ensure I had wired them correctly. Then used a 9 Volt battery to check all the cones jumped inwards on a positive signal. Then connected each set to separate channel of the EP2500 using more lighting flex. Finally, I could play Franck's organ works.

The result was very satisfying indeed . Particularly considering that no attempt had been made to balance the outputs of the two sets of drivers to ensure a smooth response. In fact the bass was a little too heavy at the previous gain settings and using the BFD filters set up for the new drivers. The detail and timbre were at least on a par with the 4 x 15" manifold and occasional sections of big pipes were incredibly heavy.

I have been trying all afternoon to capture the view inside the manifold and out through the old glazed doors simultaneously. The view through the glass is overexposed while the manifold is in almost complete darkness. I wish my skills at photography were as impressive as my new subwoofer.
*