An LLT with two AE IB15s?

[Rodny Alvarez]

If the red lights on the BFD are coming on, you probably need to turn down the sub level control at the receiver.

[htnut12]

I stand corrected, they cut the input to the amplification stage. Read that other somewhere.

[Chrisbee]

Rodny Alvarez wrote:

If the red lights on the BFD are coming on, you probably need to turn down the sub level control at the receiver.

Thanks, Rodny.

[Chrisbee]

I thought I'd better post these here just for Steve Callas to enjoy.

4 x 15" manifold IB measured with Galaxy 140.

LISTENING POSITION:



NEARFIELD:

[Sonnie]

So what exactly did you do... change to a manifold setup?

[Chrisbee]

Sonnie wrote:

So what exactly did you do... change to a manifold setup?

Yes. As simple as that, Sonnie. It was just like supercharging the array and giving it a dash of nitro. Check my signature for some pics of the new "box". Not only did I gain at least 10dB but sound quality is even better. Organ music is simply breathtaking in its depth and power. The subtlest of detail is effortlessly portrayed. On films it feels as if it can bring the house down.

[SteveCallas]

Your array must have been leaky if you gained 10db and all that low end.

[Chrisbee]

SteveCallas wrote:

Your array must have been leaky if you gained 10db and all that low end.

Rather oddly the converse is true.

The array was well sealed with thick adhesive foam draught sealer all round the edges which was compressed by lots of baffle fixing screws to the surrounding woodwork. I went to a lot of trouble in sealing it well.

I can still see daylight around my manifold because I haven't got round to finishing it off properly. The manifold was just pushed between two studs and a couple of screws hold it in place flush with the front wall surface.

The driver polarity was double checked with a battery on both the array and the manifold. In fact the array was checked repeatedly with a battery as I struggled to improve its bottom end performance. Deliberately reversing the polarity killed the bass output as one would expect.

The BFD filters remained unchanged with the manifold's installation as did the cabling. No other changes took place anywhere in the system. When I first fired up the manifold I had to rush over to turn down the volume from my normal preamp setting. It was deafening!

I have since produced another simpler BFD filter set to better match the new performance curve. This cost me about 12dB over the previous filter set but I have so much power in reserve it hardly matters. The IB is still 6dB hotter than the array with the same gain settings.

I really have no explanation for the massive increase in overall output other than the almost total reduction in mechanical vibration. The baffle wall and double doors are now almost completely free of vibration. With the array I would lean on the doors for fun while they moved about an inch in and out with ruthless power. My full weight had no effect whatsoever.

The sound quality is also much better. Particularly on organ music. I was impressed by the array but now I am constantly surprised at the subtlety of tonal colour of the great pipes and the shocking dynamic range.

The tank gunfire in "Children of Men" was terrifying as is "WOTW: machine rising".