Reference 1 driver upgrade (2017)
A few years after building my reference 1 Shig speakers, I noticed David at www.commonsenseaudio.com came out with a series of upgraded drivers. These new drivers are true full range speakers not requiring whizzer cones or phase plugs. I decided to give them a try in my main speakers.
The full build including cabinets
The full build including cabinets
Shigshop Reference 1
The old drivers
Old 8"
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Old 10"
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New drivers
New 8"
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New 10"
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The main differences are the old 8" drivers had steel baskets and whizzer cones. The old 10" also had a cool looking phase plug. The new speakers are true full range drivers with none of the mechanical crossovers (whizzers) or phase plugs. The new 8" also sports a cast aluminum basket, which the old and new 10" also possess.
The misalignment
David at Common Sense audio thought these would just drop right in. Well, the 10" drivers did, but the bolt circle on the 8" drivers was smaller. Not only that, but the new 8" cast alum basket was also slightly larger diameter and didn't fit in my cutouts. No problem - I can deal with this....
The fix
First the cutouts
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With the cutouts being too small, they had to be made them bigger. If you want to be accurate, it's not easy unless you come up with a way...
The rim of the speaker that has to fit into the hole is only about 1/4" deep and the speaker baffle is 3/4" thick. That meant I could use the hole as a guide. I took a small router and mounted a laminate trimming bit with a slightly smaller bearing set to a depth a little more than 1/4". |
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Then, using the lower half of the hole as a guide for the bearing to ride on, the top 1/4" was routed to a slightly larger diameter. The speaker would now easily fit.
With that issue solved, onto the screw holes... |
Fixing the screw holes
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This was a problem for the 8" drivers. The bolt circle was 1/8" smaller on the new speakers. With solid maple baffles, the original speakers were mounted with machine screws in tapped holes. The holes couldn't just be drilled and tapped again because the drill would have drifted into the existing hole with the result being a bit of a mess.
To avoid that, the existing holes were filled with thickened epoxy. After curing for a couple days, the excess was chiselled off, new holes marked with a punch, drilled, and tapped. |
Can't stop there!
Next, a terminal upgrade...
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The old terminals were steel. Steel isn't a very good electrical conductor. Here's a basic material to conductivity comparison using copper as a baseline (100% conductive). Silver - 105 Copper - 100 Gold - 70 Aluminum - 61 Brass - 28 Steel - 3 to 15 In other words, steel is only 3-15% as conductive as copper. It's variance is probably based on alloy content. Copper and alum screws are hard to find. Silver and gold aren't reasonable. Brass screws are easy to find, so I used those. The screws are 1/4x20, which is much thicker than the wire, so I'm figuring the conductivity will somewhat even out and is probably a much better than the old steel terminals. I made some alum spacers to make it easier to put on spade connectors. There is a set of terminals for each driver. I think they turned out great. They provide the option of bi-amping or bi-wiring if the desire ever arises. |
Completed upgrade
David said these need to break in. I immediately confirmed that. Out of the box, not much bottom end - but that is exactly what needs to break in. After being used to the old drivers, this was very obvious. They have great midrange and upper end definition, but I need to play them for a few days for the lower frequencies to develop. Imaging and separation are fantastic. Looking forward to exploring more of my music collection.
After a couple months, which has not only broken the drivers in, but has also given us the chance to listen to a wide range of music. These are the new reference speakers in my home. They have a huge soundstage in the big room with fantastic separation and imaging. Listening to my collection of jazz, rock, folk, country music, etc., I've noticed things that I never heard before - it's made some of my old music almost sound brand new. We are very happy with this upgrade - my wife thinks they are the best with no need for anymore speaker upgrades (heh... ...lol)...
To be continued...
After a couple months, which has not only broken the drivers in, but has also given us the chance to listen to a wide range of music. These are the new reference speakers in my home. They have a huge soundstage in the big room with fantastic separation and imaging. Listening to my collection of jazz, rock, folk, country music, etc., I've noticed things that I never heard before - it's made some of my old music almost sound brand new. We are very happy with this upgrade - my wife thinks they are the best with no need for anymore speaker upgrades (heh... ...lol)...
To be continued...
The old drivers
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Upgrade complete
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