There is room for modifications. I would not imagine the drivers need any modification in that John used premium cones throughout that model. The crossover components are indeed suspect. Cheap resistors is where I would start. Capacitors will clear up some background haze and premium inductors would finish the project.
I wrote a review here about my IVa modifications for your reference.
The final places to look at is the interior wiring can be upgraded and improved. I have not done this yet, simply because of money, but no doubt will in the future. Some have sealer the interiors of their Dunlavy speakers and reported gains in sonic quality as well.
Other than these minor modifications, these remain state of the art. If you have any problems with your drivers, they are still available off the shelf. This was John's idea, was to be sure they were serviceable with off the shelf products.
As for matching of drivers, yes John was big on that, and if one was to replace tweeters one might consider this. I replaced my tweeters with a premium pair on my IVa's and did not match them, yet they measured nearly identical anyway. I think this was more marketing hype than an issue, but in your case the subject is mute in that I see no need to replace any of your drivers.
I just wish I could have such large speakers, as they are spectacular...
I wrote a review here about my IVa modifications for your reference.
The final places to look at is the interior wiring can be upgraded and improved. I have not done this yet, simply because of money, but no doubt will in the future. Some have sealer the interiors of their Dunlavy speakers and reported gains in sonic quality as well.
Other than these minor modifications, these remain state of the art. If you have any problems with your drivers, they are still available off the shelf. This was John's idea, was to be sure they were serviceable with off the shelf products.
As for matching of drivers, yes John was big on that, and if one was to replace tweeters one might consider this. I replaced my tweeters with a premium pair on my IVa's and did not match them, yet they measured nearly identical anyway. I think this was more marketing hype than an issue, but in your case the subject is mute in that I see no need to replace any of your drivers.
I just wish I could have such large speakers, as they are spectacular...