Upright piano speaker simulator addon idea

I was just reading the other thread about the Keybird, which costs $3-4000, is small, portable, gives a more piano-like soundstage because it's a "scaled down" piano. It gave me an idea….

Could you create a simulated upright sound experience by making flat foam core speakers to simulate the soundboard, and then put an array of small speakers in the hammer positions to get the directionality of the hammer strikes? You could just make a box that sits on top of a long DP action, such as a VPC1. Seems like it would only cost a few hundred bucks (not including the computer to run Modern U).

When I worked at a industrial design company 15-20 years ago, when Finite Element Modeling was fairly new (on PC's anyway), I got to experience foam core speakers. Definitely a more diffuse, less directional sound than a standard cone speaker. I'd think that sort of sound is much more like a soundboard.

Hello,

I've been toying with such ideas. I even contemplated using a soundboard from a written-off piano and mounting transducers on it in strategical places (e.g. bridge locations where normally the strings would excite the soundboard).

To get closer to the upright sound field feeling, I installed six bookshelf-type Wharfedale speakers fed by four channels (through two stereo Onkyo amplifiers). I described this setup in the Modern U thread:

HZPiano A huge Modern U fan here as well

This works so well and enjoyable already, that for some time to come I don't see myself toying with a transducer project. However interesting it may be!

Cheers and lovely sound fields,

HZ

Hello,

I learned a lot from this video:

And it's sequel:

Cheers and happy science experiments,

HZ

I think Wharfedales are beyond my experimentation budget… I currently use studio monitors and a studio amp that I've had for decades. But mostly I just monitor with headphones. If I want to make alot of noise, I play my Mason & Hamlin.

But it seems like you could design an add-on to a Keyboard controller that turns it into a hybrid piano.

dore_m If I want to make alot of noise, I play my Mason & Hamlin.

😄 Which, in turn, is way outside of my 'experimentation' budget.

By the way my Wharfedales didn't break the bank. Two of the six I got second hand, the other four are new but of a discontinued model that I could just in time lay my hands on before stock ran out. The amplifiers are from second-hand and charity shops and restored to fine working health by myself.

They're lovely sounding though, I even got a third pair of the same discontinued type that I use for TV, CD listening etc. Also restored-Onkyo driven.

Cheers and happy making some noise,

HZ

FWIW, this is exactly what I plan to use for my Cybrid. Stay tuned for details, which I will post as a "how to build your own hybrid - the sound system" series

RIP FWIW, this is exactly what I plan to use for my Cybrid. Stay tuned for details, which I will post as a "how to build your own hybrid - the sound system" series

Its funny - its like you and I have the same goals, just coming at it from different directions.

dore_m Its funny - its like you and I have the same goals, just coming at it from different directions.

Yes, and often quite different directions!

Regarding this one, do you plan to do any experimentation? The AmplifyDIY videos are very good (especially the follow up one) but he did not test the higher compression strength foams, nor the different thickness which according to the manufacturer of the exciter are very important for good results. He did not test size either, but that's less of an issue since we know how that goes: bigger is lower frequency (and moreover often one is limited in size to the available space, so it's a moot point).

Anyway, I intend to do some tests with various foams, purchasing from https://insulation.supply/custom-insulation-board/ rather than Home Depot (well, maybe I'll buy the first couple at HD, since it has 0.5" and 1" @ 15 psi of compression strength, aka 150 from the manufacturer). But from IS I could buy the following 2'x2' samples (which will ship UPS rather than freight), with the following price estimates (by me, not officially from them):

1000 @ 2" ($31 2'x2' boards in their boxes)
600 @ 2" & 1" ($14 + $7, based on 4'x8' cost ~ 1.8x the 150)
400 @ 2" & 1" ($14 + $7, based on 4'x8' cost ~ 1.7x the 150)
250 @ 2" & 1" ( $8 + $4, based on 4'x8' cost ~ the 150)
150 @ 2" & 1" ( $8 + $4, 2'x2' boards in their boxes)

For a very reasonable total of about $97 (HD sells only 150 @ 1" in 2'x2', everything else is in huge 4'x8' and each of those cost easily 40 bucks -- besides not having anything stronger than 250). In any case, better coordinating among us to avoid duplication of efforts and instead seek multiplication of results 😉

RIP In any case, better coordinating among us to avoid duplication of efforts and instead seek multiplication of results

RIP Yes, and often quite different directions!

I think we both are trying to create a satisfying piano experience - and we both have genuine Mason & Hamlin pianos that are, incidentally, literally 1-2 years apart in age from the original Boston Factory during the Golden Age. My aspiration (it's not really a goal yet), is to put a silent bar and MIDI controller electronics (QRS, Cybrid, whatever) into my M&H, and be able to play a simulated version of different types of pianos, and do it as realistically as possible. A couple of years ago I was researching adding dayton audio exciters to put onto my soundboard, but thought that would really kill the tone of the piano by adding the extra weight. But now I'm really wondering if I could just arrange flat speakers somewhere around the piano (beneath, above, behind ??). Just thinking….

The modification of the action part of my piano is so challenging that I've resorted to using software tools (VR and ambisonic recording) to make as good a virtual reality piano (with headphones) as I can - which is where my project stands today. I don't have the room to make a Cybrid, so I'm more focused on either adding to my small DP or modifying my real piano.

So, while I'm really interested in trying the flat speakers, I probably won't make prototypes until I think of a good way to incorporate them. I did see in the Tech Ingredients video that he decided to just make many speakers of different materials. Apparently using multiple materials evens out the response instead of fine tuning one material/shape. However, he did mention that the ceiling tiles worked really well - had good highs like the poly foam and good lows like the balsa wood. So if I try, I might do that option first. Who knows? Maybe I'll put in an order for those exciters (for the ones on backorder for really cheap) and try next year.

RIP In any case, better coordinating among us to avoid duplication of efforts and instead seek multiplication of results

And certainly at some point you're going to get to the audio processing side of the VI, because you can do alot to fine tune. So I gotcha there - I can help.

dore_m But now I'm really wondering if I could just arrange flat speakers somewhere around the piano (beneath, above, behind ??). Just thinking….

I think underneath is the easiest and more natural. But that is just me thinking out loud.

dore_m So, while I'm really interested in trying the flat speakers, I probably won't make prototypes until I think of a good way to incorporate them.

I'll let you know what I find, then.

dore_m I did see in the Tech Ingredients video that he decided to just make many speakers of different materials. Apparently using multiple materials evens out the response instead of fine tuning one material/shape.

I saw that. However the materials different from polystyrene had drawbacks. Balsa is extremely expensive. Ceiling tiles somewhat heavier and very brittle, so extremely hard to cut and drill. In the end, polystyrene is the most cost effective. But everybody has only tried one thickness and one compression strength, and we ought to fix that, because the material is easily available in different thicknesses and different compression strengths and those two parameters are important.

dore_m And certainly at some point you're going to get to the audio processing side of the VI, because you can do alot to fine tune. So I gotcha there - I can help.

Yes, I do. On that topic, let me start another thread

RIP I think underneath is the easiest and more natural. But that is just me thinking out loud.

I saw some vids of Pianodisc being installed where there were traditional speakers strapped to the bottom of the piano. The main reason I have a grand is because I grew up having the sound of the piano coming up at me from in front of me. So that would imply that I would need to cover the topside of the soundboard, which is not ideal for the piano itself. I guess the only ideal solution is to do what you're doing. Make another one! Or maybe make a "flip out" mechanism….

dore_m The main reason I have a grand is because I grew up having the sound of the piano coming up at me from in front of me.

Well, these foam things are said to be not as pin-pointable as sound source in space as speakers are, so it's still something to try and would not cost much to experiment: hanging some fishing line from the piano beams underneath to hold it as close to them as possible without touching (which would cause buzzing). Alternatively, you can hang the foam thing from the ceiling, or make wall panel or… really part of the beauty of this design is that's it is so flexible that you can do everything with it. Not saying that everything will work "just fine", but you have many many things that are very easy to try and see how it goes -- compare that with even a bookshelf speaker, not to mention a largish floorstand one and how much work would be needed to simply test "how would it sound if I hang it on the ceiling where I think is the best position for sound to come from and I have all that cubic footage available?"

dore_m I guess the only ideal solution is to do what you're doing. Make another one!

That will work too, but you do need some square footage for that. Not much, but you said you don't have it…

Actually after I wrote that I realized that I could literally put a large one beneath the piano on the floor radiating upward, and put one on the piano lid. So when i'd want to play, I would just close the piano lid and the speaker would be right there radiating upward.

I have heard the sound of those types of speakers (but in the distant past). The sound is more diffuse, and more like a soundboard, but as you already figured out, it will take some experimentation to get the timbre to match. But having the diffuse sound actually is the novel part that cannot be reproduced that well with commercial speakers - so I think it's the right direction.

So one experiment, if you get to it first, will be to see how well the speakers radiate in a horizontal position. I'm wondering if the mass of the exciter will greatly affect the panel vibration in that direction.

dore_m So one experiment, if you get to it first, will be to see how well the speakers radiate in a horizontal position. I'm wondering if the mass of the exciter will greatly affect the panel vibration in that direction.

I am not interested in that use case myself, but the test won't cost me much (just hanging the panel somewhere horizontally) so that's a great idea for me to test that too.

dore_m Actually after I wrote that I realized that I could literally put a large one beneath the piano on the floor radiating upward, and put one on the piano lid. So when i'd want to play, I would just close the piano lid and the speaker would be right there radiating upward.

I believe that would be tricy because if those panels touch static objects such as the floor or the piano lid, buzzing is guaranteed. But you can still hang it from the bottom of the piano to almost the floor… of course you can attach the back of the exciter as he showed in the follow-up video (even though he was doing so horizontally)

RIP I believe that would be tricy because if those panels touch static objects such as the floor or the piano lid, buzzing is guaranteed.

Yeah, you're right. Seems more tricky than I expected. The upright piano idea probably is easier, but just not my personal end goal.

So after forgetting about this discussion for awhile, I just decided to buy some Dayton Audio transducers during Black Friday because I was planning on doing some experiments next year - most are on backorder, unless you want to pay a premium. I just decided to plan early and order early.

As luck would have it, two came in today, and I spent about an hour playing around with them. I first just put them on cardboard, and they sounded ok. Then I put it on the face of my Cajon and because the material was smaller in size and wood, it had less higher frequencies (or maybe because the edges of the surface were constrained). About that point, I realized that I could just push them up against the bottom of my piano's soundboard to see what they sound like. I definitely wasn't going to use the permanent tape.

Anyway, surprise, surprise….. Sounds alot like a Yamaha Transacoustic. I may have to do some recordings of the piano and the transducer/speaker to get some frequency spectrums to decide what to do next. The good news is that even though the position of the transducer can roughly be heard, the sound does project more like a piano than a cone speaker. If I position multiple transducers strategically underneath the soundboard, possibly along the bridge, the sound radiation will probably feel like a real piano, Now, if I can get the correct frequency spectrum so it also SOUNDS like a different piano, then I can play a Fazioli on my Mason & Hamlin, and actually have it sound and feel that way. Is it a pipe dream? At about $20/transducer its fun to try.

Do you want to compete with Resonance : https://resonancepiano.com/en/ ?

dore_m Now, if I can get the correct frequency spectrum so it also SOUNDS like a different piano, then I can play a Fazioli on my Mason & Hamlin, and actually have it sound and feel that way. Is it a pipe dream? At about $20/transducer its fun to try.

I tried that with my former grand, without being too "aggressive" in my quest. So my conclusion was simply: too much work to make it worth my time for me. Well, that was a 4' grand, and my main objective was to try to make the virtual instruments sound more "woody" (a shift in timbre), which they didn't.

The biggest problem which I encourage you to study is the attach-detach problem. The guys in the links above used sharp knives to detach and new strong adhesive tape to reattach (I communicated privately with them about it). But hey, at worse they would trash a $20 toy and some even cheaper pieces of scrap material: you don't want to do that with your soundboard. You may put an intermediate layer (e.g. the ole fashioned transparent plastic used for the real "slide projections") strongly attached to the transducer. Then use some other approach to attach that to the soundboard in a way that's sturdy enough to hold and not fall (and transmit the sound well and not buzz), while being easy to non-destructively removed. Please share if you find an ideal solution for this!

RIP The biggest problem which I encourage you to study is the attach-detach problem.

I played with it more last night and I think there isn't a good way to get the sound to come close to the timbre of another real piano. I might keep trying with a hybrid approach of soundboard + speakers near the hammers. I feel that the big players (Yamaha, etc) would have already done something like this if it were simple, but they probably wouldn't do such user unfriendly things like manual attach/detach methods, or 10 transducers, or something crazy that I might personally put up with.

If the soundboard thing works (and I'm not that hopeful), I'd probably just design a lever mechanism attached to the bottom of the piano structure where I can shift a lever and couple the transducer to the soundboard. It's not ideal, but so far I haven't heard much difference in sound quality when I just hold the transducer on with different pressures. I'm using a mic stand and a shockmount, which is basically a spring. Don't know how this added spring/mechanism will affect the sound.

Last night I also just put the transducer on a cardboard box and laid it on top of the piano. The frequency range was better, so I still may continue with this scheme of tuning a large speaker (2x4 feet) and placing on top of the piano lid. Still experimenting with whether or not the soundstage is similar to the real thing.

Frédéric L Do you want to compete with Resonance : https://resonancepiano.com/en/ ?

Interesting. Not trying to compete. I don't have any interest in making money from this, just an interest in trying to DIY a system that is really good for personal satisfaction. Thanks for the link, I may learn something…