Posts tagged plate
I must say if there’s one thing i know little about, it’s the COMPARISON of cast iron plates in pianos with regards to tone. We don’t really have the luxury of comparing identical models of pianos with different cast plates in them. I am referring to the difference between traditional sand cast plates vs. V-Pro casting. I can spot a traditional sand cast plate a mile away but does it affect tone? Hmmm i’m not so sure… but here’s what i DO know (which might be dangerous – as they say “a little knowledge is dangerous”)…
Traditional sand casting: Make a model. Press it into sand… remember making a mold of your hand in plaster when you were a kid? Same thing except that the master model is a piano frame. Once the ‘relief’ is in the sand, they pour molten iron into the mold.
V-Pro casting: Make a model. Cover with a plastic sheet. Add sand on top of that. Sandwich with another layer of plastic. Using a vacuum (V, by the way stands for Vacuum… Pro is for process = V-Pro)…. suck the atmosphere out of the sand bag sandwich and it very accurately mirrors the model. That then becomes the new relief mold. Make sense? Have you ever seen those ads on TV for leftover food where they suck the air out of the bag and it tightly forms around the contents? Well that’s what’s happening here.
So what does it matter? If it’s traditional sand cast or v-pro? Well the sand cast looks rough while the v-pro looks absolutely finessed. There’s barely any finishing required on v-pro while the sand cast needs a fair bit of attention to call it complete. I read today that the v-pro plates create bad harmonics. Though i’m not ruling it out, I’m not buying that either. I don’t doubt that the cast may be vibrating, but by comparison to a wooden soundboard and felt hammers, i truly believe that the bulk of any overtones are going to be coming from the interaction of those parts rather than the cast. So why the big deal? If iron is iron and one comes out looking better than the other, why do some people talk about v-pro like it’s in question? I’m not entirely sure but i have some hunches. If the sole purpose of the frame is to be the backbone of the piano – the rigid stabilizer – then mass is always better. Quite often to compensate for traditional gravity based casting, the “more is better” motto is applied. If it means that they make a bigger, chunkier plate JUST to make sure that all of the cracks and crevices get filled in when pouring, so be it. In the v-pro arena, casting is much more accurate and is also more efficient. My own thinking is that the cast iron pianos with v-pro are thinner. That’s my wager. From the pianos i’ve seen (especially older ones) where they are really robust, invariably the cast iron frames are also beefy. Back in January – visiting a few boutique piano manufacturers, one intimated that the casts were traditional sand cast… intimating they were somehow superior. Isn’t that interesting? Low-tech can still be considered superior? Well jury is out for me. I can’t actually speak from personal experience because i’ve only seen isolated cases on both sides for comparison. And really, there are WAY more variables than just the cast from which to compare. I’ve never seen two pianos from the same year, model, size etc with 2 different plates to compare. But i WILL go on record saying that there is ONE thing that i do know to be generally true: heavier pianos (ie more iron) are USUALLY better instruments. Other than that… my little knowledge… is just… dangerous.