Hybrid open baffle build

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Curlycat

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Hybrid because it is a combination of vintage drivers and modern drivers. Hybrid because amplification is a vacuum tube preamplifier and a solid state power amplifier.

This is not a high-tech expensive jaw-dropping build. It is more a build to express what was done with inexpensive parts, an easy build that resulted in the best sounding system I have had (I have gone through a lot - some very well known and admired kit) Apologies for the quality of the pictures, I actually had no intention of posting this build thread.

The build was designed around a quad set of vintage alnico Philips AD1255 drivers. (Thank you Kent Kassler - as always!)
Since I had 4 drivers, I planned to do a MTM (midrange-tweeter-midrange) setup for the top section and a big woofer for the bass at the bottom.

Here the Philips arrived and a quick connect up to hear what they sound like. They are 12" full-range drivers.



The baffle is made from standard off the shelf laminated pine shelving. I purchased one length of 2.4m x 610cm wide. This was cut in two to give me two baffles of 120cm high.





Getting ready to test on the baffle for the first time. This is the big moment when I will actually hear what these drivers sound like on a baffle.



It was a go! They definitely had potential to proceed with the planned build.

Next was to drill the hole for the tweeter and to add the wings. I wanted to keep the mids and tweeters as close together as possible to assist with pinpoint imaging. I suppose one can actually call it a U-frame open baffle. In my experience with open baffle designs, I always achieved better sonic results in the midrange with a bit of a side wing. In the past, no wings sounded a bit thin. The wings once again, shelf bought pine, 2.4m x144mm two lengths cut in half. Solid pine this time, not laminated.  The woofer was mounted on a double baffle. I reinforced the bottom section with a second sheet of laminated pine.





Next up was to router the hole for the 15" PA woofer. I used a cheap Hybrid H200 15" driver. Specs of the driver were well suited for an open baffle build. Also does not have a foam surround, so I don't have to worry about foam rot over time.

The woofer was front mounted and the Philips was mounted from the rear, the reason is to try and keep the voice coils of all the drivers more or less in time alignment.





All the drivers mounted - just the tweeters still missing. I did some extra reinforcement on the top section of the baffle as well, since it was just a single sheet of wood. The vacuum tube preamp is visible on the left.





 
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