Topic: Tactile Transducer
First of all, let me preface this by saying that my goal with building my Pianoteq setup has been to create an instrument as near as possible to a concert grand piano (no brand names) in most ways. My piano experience is purely classical, and since I don't yet have the resources to own a concert grand and a house big enough to put it in, I think Pianoteq gets me very close in sound quality. I don't think everyone here has the same goals as me, so keep this in mind if you think what I did was crazy or misguided.
After buying my first-ever digital piano (Roland HP203, selected for the feel of its action), I immediately connected it to Pianoteq running on a laptop, with the sound feeding back into the piano's line-in. This worked great, but I wanted more. I got external monitors (some Alesis USB monitors) and they were better, but not fantastic. The laptop also wasn't very practical because of limited desk space around the piano, so I upgraded to a Mac mini (and made it a dedicated piano/media computer). I also upgraded the monitors (M-Audio BX5a's) and got the Firewire Solo for better latency and balanced audio lines. This setup sounded fantastic, but my monitors sit on stands, so after a while I realized that the piano felt dead, even though it sounded great. There weren't any vibrations feeding back into my hands to convince me that the sound could be made by strings and a soundboard. I could split the audio and run it through the piano's speakers, but I figured that would muddle the sound quality, since the piano's speakers would have to be fairly loud to get "real" vibrations.
My solution came from browsing the Parts Express website. They sell these Dayton Audio exciters (aka tactile transducers). You've all seen those portable "speakers" that really just stick onto a surface and use it as an improvised speaker cone. Same thing. So I purchased two exciters and a small amp and planned on just hooking them up in parallel with the monitors, but I realized that it would be hard to split the balanced audio lines. The Firewire Solo has an SPDIF Out, so I also got a cheap SPDIF-to-analog converter from Monoprice and set the SPDIF output to come from a third and fourth channel in Pianoteq. This also gave me the ability to tweak the virtual mics where the tactile feedback would come from, independent of the main mics going to the monitors.
Not being a sound engineer, I just assumed that the best place to attach the exciters is on the bottom of my piano. Obviously the bass strings vibrate the piano more than the treble strings, so I roughly split the bottom half of the keyboard into thirds and stuck the exciters on those points (roughly around A1 and B3, I think) about half-way back. All very unscientific. I was greatly pleased when the exciters ended up not producing very much sound at all, even with the amp maxed out. That meant all the "good" sound would still be coming from the monitors, with the exciters putting off significant vibrations into the key bed and even the pedals.
Well, I have to say, these things are amazing. It feels "real" again. I initially had a big buzzing resonance on a couple octaves of B, but I tweaked the delay on one of the tactile mics in Pianoteq and the resonance went away.
All said and done, it was around a $75 upgrade to my piano. Sure it's a small addition that might not make sense to some people.. Will it sound any better? No. Will I play any better with the added feedback? Maybe, but that's highly debatable. It's the very definition of "aesthetic".. Not practical and not that beneficial to anyone but me, but that's what my music is already.
So take all this for what it's worth - an avid amateur's attempt at total realism. If I did something completely wrong and don't yet know about it, if you've done anything similar, or if you want any more info, please let me know.