Lowther Opus One: impressions?

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I am in the process of finalizing plans to build a set of Lowther Opus One horns with PM4A drivers, silver coils. To that end, I have located a woodworker willing to take of the commission and I am attempting to purchase the drivers and plans.

I have reviewed the previous threads regarding Lowther Opus 1 impressions and builds but they are all very old threads. I would like to know if anyone in the community has any first-hand experience with these horns.

Also, has anyone purchased the drivers from Lowther direct? I have looked at the website for their US dealer and been unable to order. There doesn't seem to be anyone to answer the phone either.

The builder that I've found works for an organ building company as a woodworker. I feel luck to have found him. He is used to building big wooden boxes that are beautiful to look at and listen to.

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Lowther Opus One

Hi there, you do not state WHICH Opus One you wish to build.
There are two. Model A and Model B.
I've been working on Model A for quite a while, with many interruptions.
Model B is simpler but I'm reliably informed that the bass drops "like a stone" below 60Hz."
I was told this by someone who built cabinets using Lowther drivers for a number of years.
Model A goes comfortably down to 30Hz.
Another retired cabinet maker I corresponded with in 2005, made both Model A and TP1 - he worked very fast and had them both finished within a few weeks. He had previously built a number of Lowther cabinets.
His impression was that Opus One A was very clear across the frequency spectrum. He was using EX4 drivers, and exhibited at the Heathrow Audio show in 2006.
I think the difficulty of making Lowther-designed cabinets puts off many.
TP1, Opus One A and Audiovector are NOT easy to make. Jon van Halen, erstwhile Lowther America, described the Opus One A as an "awesome" loudspeaker in these forums.
If you want to listen to electronic thumping bass, then choose something cheaper and easier to make. Lowther drivers are very honest.
I spent 30 years working with professional broadcasting equipment, recording and broadcasting classical music. Lowther drivers are at the very top of the reproduction chain.
(We used Tannoy and B&W as studio monitors.)
For Lowther I would contact Scottmoose to see if there is an easier and potentially better option for your chosen driver. Many cabs of old are just way too complicated to build when they really do not need to be as other options are now available. My penny's worth :)
Interesting that Lowther have changed hands. It'll be interesting to see where the new owners go with it.

Regarding the Opus A, that does look a fearsome build. Having constructed horn loudspeakers in the past (not Lowther), if you have the room I can recommend something larger and simpler. Most of the convolutions in that Opus cabinet are designed to compact the horn length into a smaller space. Have a look at Nelson Pass's ideas for an extreme example of simpler + larger.
Ticonal is a trade name for the magnet, see here from wiki -

Alnico is a family of iron alloys which in addition to iron are composed primarily of aluminium (Al), nickel (Ni) and cobalt (Co), hence acronym[1] al-ni-co. They also include copper, and sometimes titanium. Alnico alloys are ferromagnetic, and are used to make permanent magnets. Before the development of rare-earth magnets in the 1970s, they were the strongest type of permanent magnet. Other trade names for alloys in this family are: Alni, Alcomax, Hycomax, Columax, and Ticonal
Plus One A is a tricky build. Maybe have the pieces cut to shape with CNC would make life easier? There're many accurate bevels to cut as well. I have dwg drawings from Lowther on CD.


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