A brand new Steinway from VSL: 1887 model D concert grand

David B It wasn't that difficult. Couple mics, my laptop, an audio interface, and I uploaded it right from that sanctuary. Maybe it's not considered properly done, but I think it accurately captures what that piano sounded like in that space at that time.

Exactly my words: you went to a special venue (church), spacious probably but I can see it was not optimally placed. On the other hand you record two close‑up mics only (it seems), so that is just that. Minor phasing I could hear but that is normal with such setup. Needs E] for sure (no, it won't destroy "the real sound" of the piano because it is not "the real sound" — it is the sound of the mics, each with its own EQ freq. resp. profile). Then, of course, more mics = more difficulties

David Lai to record well requires effort and skill

Exactly my words.

David Lai sample library makers know how to do it

Not my words.

I can write down here how it should be done (if mics are to be used) but it is pointless.

1. you need a proper ac. treated studio with cable mics coming down from ceiling (6 mics) to the strings
   4 close‑up + 2 (a stereo pair to capture studio reverb)
2. remove the lid (completely), place the close‑up mics: low, mid, upper mid, highs to their resp. zones (trial error) → small record bits to test
3. cover the iron frame with some fluffy sleeves, put some thick carpet(s) under the piano and smaller ones to cover studio floor
4. adjust height and spacing for proper phase alignment (trial error) → small record bits to test
5. check levels (soft to very loud playing) adjust height of stereo pair mics (phase align to close‑up, could\should be done also in post‑recording stage, mixing)

No mic stands (important) and the mic cables should be wrapped with some soft material sleeves (bands) to prevent strung "string" function. That's it.

PASHKULI seems very specific. You’ve tried this recording method how many times successfully thus far? Please share some recordings.

dikrek

I have not, because I do not have those items mentioned.

Jose EB5AGV

Thank you for your pragmatism!

👌

HZ

CyberGene we’re not at war with the acoustic, we love it.

Hear, hear!

💚

🎶

HZ

PASHKULI then it’s not an axiomatic statement as you presented it but rather your theory.

Until proven, you need to be clear that this is what you suspect to be true.

CyberGene You don’t see Ferraris that often either but aren’t they the most desirable cars? 🙂

They are!

Gifted one, I'd sell it in a heartbeat and buy myself a succulent CFX!!

😋

🏎️ --> 🎹

HZ

HZPiano anything that even used commands a higher price than new, is, indeed, very desirable, by definition.

dikrek

It is a possibility. An idea. A try if you will. Backed by irrefutable logic.

How much "better" it will be? I have no idea, so compared to what objectively? Maybe sound louder, more balanced?
Will it need post production tweaks mainly EQ? Of course it will. Microphones were used. On its own it will need some, in a mix with other instruments it will need more — that is mixing as part of audio engineering.

Everything was (is) a theory until proven right or wrong by experimentation or experienced.
Let's say that it is how I would have done it. Acoustic pianos are the biggest in size instruments (next after pipe organs).

Yes, I know that proof is in the pudding, not in the recipe.

PASHKULI irrefutable?

I think there’s a mixture here of some good recording practice and quite a lot of cargo-cult engineering.

A good room: yes.

Experiment with mic placement and actually record test passages: absolutely.

Check the complete dynamic range and listen carefully for phase/comb-filter problems when combining multiple mics: yes.

But I don’t understand why the rest follows.

A grand piano isn’t four loudspeakers called bass, mid, upper-mid and treble. The strings excite bridges and a very large soundboard, and the radiation pattern is extremely complicated and frequency dependent. One of the reasons a grand sounds like a grand piano at some distance is that all of this integrates acoustically.

So starting with four close microphones and reconstructing the piano afterwards seems rather backwards if the objective is a natural piano recording.

Likewise, why is removing the lid automatically correct? The lid is part of the acoustic design of a grand and changes its radiation into the room. You can absolutely record lid-off if that’s the sound you’re after, but it isn’t some objectively superior configuration.

The bit I disagree with most is “phase align” the six microphones.

Phase-align them to what, exactly?

You have a physically huge source, different strings in different locations, a vibrating soundboard, four close microphones, two distant microphones and hundreds of frequencies. You can time-align the arrival from one chosen location or transient. That doesn’t somehow phase-align the entire piano.

And if the distant pair exists specifically to capture the room, why would I necessarily want to time-align it to the close microphones anyway? The delayed direct sound and early reflections are part of the information that creates perceived distance and depth. Removing that delay can partially destroy the very spatial information you’re trying to capture.

Same problem with covering the frame in fluffy material and carpeting the floor. What specific audible problem has been measured or identified that we’re fixing? If there’s a bad floor reflection, fine — deal with it. But if I’ve paid for a beautiful acoustic room, I’m certainly not going to start covering reflective surfaces just because reflections exist.

“No microphone stands” being important also needs an explanation. Good stands and shock mounts are used on excellent recordings every day. Hanging microphones can be useful for sight lines, access or isolation, but there’s no obvious acoustic principle by which a microphone becomes better because its cable comes from the ceiling.

Likewise, secure your cables so they don’t transmit mechanical vibration. Fine. But dressing every cable in fluffy sleeves so it doesn’t become a resonating “string” sounds rather like a solution looking for a problem.

For a natural solo grand recording I’d start almost exactly the other way around:

Find the position where a very good stereo pair already captures the piano as a coherent instrument in the room.

Then ask what is missing.

If I need more attack, definition or control, add close mics. If I need more room, add an ambience pair.

Six microphones might eventually be the answer. But “six microphones” shouldn’t be the premise.

The fundamental difference is that I’d try to record the piano, whereas your (100% unproven) approach seems to record a collection of piano components and then try to reconstruct the piano afterwards.

PASHKULI "I can write down here how it should be done (if mics are to be used) but it is pointless."

Exactly, because you not only don't play the piano, you don't like the piano, and you don't record the piano. So, what makes you so proud in talking about recording the piano, and in this weird way as you've proposed?

Rach3master is on pianoclack I believe. His recordings (of NY Steinway D) are excellent, I'd ask him for his mic setup and that's all there is to it.

His Garritan CFX VST settings were also quite good if I recall.

dikrek

You used AI agent to write that long response. Deny it and we will go on a giant off‑topic (it can be verified with antiAI although you might have touched the formatting here and there → reminds me of our private conversation). Cheeky.

I do not mind. AI is still learning.

dikrek The bit I disagree with most is “phase align” the six microphones.

Effing AI at it right there. So…

On piano, being a big musical instrument, you can place many, many mics. Ideally, I would have placed Nu‑multi pickups under each note's strign(s) and piezos on bridges. But we are restricting ourselves to microphones (typical acoustic recordings).
Ok, use 5 mics (close‑up) if you will. Or another one under the piano → that confined acoustic space also contributes to the overall sound.

Use 3 close ups (at least). Low, mid, highs, omni directional. One mic → no problems, two mics (stereo or binaural) → you can\will get phase issues unless you know what you are doing (pointing parallel, 90° or worst is 180° to one another). With omni mics it is expected and inevitable. More direct pattern mics, more individual ranges but heavier setup. Hence → better is with individual pickups.

It is cringe that I have to write this self evident rant but we all learn at some\any point.

The lid. Ok, keep it closed. The only way the sound comes out of that "box" will be from underneath (and rumble resonance of cabinet and lid) → the opposite sound of the soundboard where the strings are blocked by it. This setup has nothing to do with any other string instrument. None. So, good luck.
Remove the lid. Expose the string and the soundboard. Dampen as much as possible reflections from metal frame. It is not and should not be a part of the acoustics → it is a structural reinforcement. But being metal and hard it reflects and shifts the real sound of string, soundboard and cabinet.

Phase aligning is only valid between 0 to 200Hz above which it becomes an impossible task to align denser freq. waves. That is why in audio mixes all instruments but bass (incl. synth bass) and kick drums are cut off either with deep shelf (as I prefer) or more generally with a 12 to 24dB even 36dB or 48dB (extreme) per renova ("octave") slope low cut. Mics capture it but it is not needed.

Hence on those piano mics I place, only the low and low mid will have info there (0 to 200Hz) → the other (2 or n) mics will get a shelf cut there. Phase alignment will be much facilitated that way.

The stereo (room\studio) pair does not need time alignment → it is distant for the reason to capture late reflection off studio room acoustics. But it will have low information below 100Hz at least which is not important. The bass strings from ≈30Hz to 120Hz have their fundamentals lower in dB than actual harmonics of new (well cleaned) strings (usually wound coiled too). So you do not need that rumble especially on distant mics which will only mess up the phase. Phase between each mic in the stereo pair should be checked and mics adjusted if need be.

dikrek For a natural solo grand recording I’d start almost exactly the other way around:

Find the position where a very good stereo pair already captures the piano as a coherent instrument in the room.

That is because you do not want to record the piano but the acoustic environment in which it is placed\used\emitting sound.
I am talking about recording the piano itself. And in fact would prefer to replace the room stereo pair with IR (impulse response) sets.
For the latter though the actual room should be close to anechoic (if too expansive — it is — to do all this in a proper anechoic one).

dikrek The fundamental difference is that I’d try to record the piano, whereas your (100% unproven) approach seems to record a collection of piano components and then try to reconstruct the piano afterwards.

F‑off AI.

PASHKULI I think this clarifies our actual disagreement.

If your objective is to record a very dry piano in something approaching an anechoic environment and add the room afterwards, that’s completely legitimate.

But I don’t think that makes the result the uniquely “pure piano sound”. Anechoic capture removes the room. It does not remove the spatial complexity of the piano.

There are three reasons.

1. Even an anechoic grand does not produce one canonical signal

A grand piano is a large, directional acoustic radiator. What a microphone captures depends on where it is.

This has actually been measured in an anechoic chamber. Nakashima, Giron and Tohyama measured piano radiation on a 2 m-radius spherical surface, in 10° increments from above to below the instrument and around the full 360° horizontal plane, specifically to derive direction-dependent piano responses. (AIP Publishing)

So anechoic piano sound at position A is not identical to anechoic piano sound at position B.

Both are “the piano”.

That is why I think dry is a much better word than pure.

2. If you want to add the room later accurately, piano directivity matters

This is the really important consequence.

A conventional IR assumes some source position and radiation behaviour. But the actual piano sends different spectral energy in different directions, and that behaviour can change from note to note.

Researchers have tackled almost exactly the system you’re proposing: record instruments anechoically, then reconstruct their interaction with a virtual room.

Their solution was not simply “close-mic the instrument and convolve it with an IR”.

They recorded instruments — including grand piano — with 5 or 13 microphones distributed around them, then represented the instrument in the room simulation as a compound directional source, one component for each anechoic channel. (Welcome to DTU Research Database)

That’s the crucial distinction.

If you collapse the grand into a few close bass/mid/treble signals and then apply ordinary stereo IRs, you can certainly create a convincing and perhaps beautiful result.

But you haven’t recreated all of the piano–room interaction that you deliberately discarded.

3. Removing/damping parts of the piano is then a creative choice, not purification

This is where I think the “pure piano” argument becomes internally inconsistent.

If the objective is genuinely:

piano minus room

then put the actual piano into the anechoic environment and measure what it radiates.

But if before doing that you:

• remove the lid;
• damp reflections from the frame;
• carpet underneath it; and
• decide which structural contributions constitute “real piano”,

you’re no longer merely subtracting the room.

You’re changing the source.

That may produce a sound you prefer. Nothing wrong with that.

But it is a designed dry source, not some objectively purer version of the instrument.

And that’s ultimately my point.

Your approach could be very interesting for a sample library because you’re optimising separation, control and reconstructability.

But if you genuinely want the most rigorous version of:

anechoic piano → add arbitrary room later

the acoustic research actually points towards more spatial capture of the dry instrument, not fewer microphones divided into keyboard zones.

Ironically, your underlying idea is more defensible than the recording method you’ve proposed for implementing it.

And that makes it an interesting experiment — just not “irrefutable logic”.

PASHKULI The phase argument can be reduced to one point:

Multi-mic phase interaction around a piano is real, but the rules you gave for it are not.

There are three separate issues.

1. There is no 200 Hz boundary

You wrote that phase alignment is only valid from 0–200 Hz and becomes impossible above that.

For a pure delay:

phase shift = 360° × frequency × delay

So yes, higher frequencies are increasingly sensitive to small timing errors because their wavelengths are shorter.

But there is no special transition at 200 Hz.

If one signal is simply another delayed by 1 ms, compensating that 1 ms corrects the time offset broadband.

The real difficulty with several piano microphones is that they are not identical delayed copies. Each hears a different mixture of strings, soundboard radiation and reflections.

Therefore no single delay can perfectly align every note and frequency.

That’s true both below and above 200 Hz.

2. Turning an omni 180° does not create a 180° phase inversion

Real omnis become somewhat directional at high frequencies, so orientation can affect their HF response.

But physically rotating an omni microphone through 180° does not invert its polarity.

Those are different phenomena.

With spaced omnis, the important timing relationship comes principally from their positions relative to the source.

In fact DPA deliberately uses arrival-time differences between spaced omnis to create stereo localisation, and recommends spaced omni techniques for grand piano.

So “parallel good, 90° worse, 180° worst” is not a general phase rule for omni microphones.

3. Phase differences in stereo are not automatically errors

A/B stereo deliberately uses inter-channel arrival-time differences.

Those differences help create the stereo image.

That does not mean phase interaction is irrelevant. Combine sufficiently correlated signals with different delays and you can certainly get comb filtering, particularly in mono.

So checking mono compatibility and destructive interaction is good engineering.

But:

detecting a phase/time difference does not imply that the correct solution is to remove it.

Sometimes that difference is part of the recording technique.

Likewise, high-passing some close microphones below 200 Hz may reduce overlapping LF energy and therefore reduce interference.

That’s perfectly reasonable.

But that’s filtering, not phase alignment.

So I think five things need to remain distinct:

Time alignment — compensating an arrival delay.
Phase relationship — frequency-dependent phase difference.
Polarity inversion — flipping waveform polarity.
Filtering — reducing spectral overlap.
Comb filtering — interference when correlated delayed signals are summed.

They interact, but they are not interchangeable.

So yes: six microphones around a grand require careful phase management.

But the physics does not reduce to:

“phase alignment works below 200 Hz, becomes impossible above it, and two omnis pointing 180° apart are the worst case.”

Those specific claims don’t hold up.

PASHKULI Separate point on covering/damping the iron frame, because I think the premise here is backwards.

The fact that the frame’s primary function is structural does not make it acoustically irrelevant. And if the goal is “piano minus room”, altering the frame is altering the piano, not removing the room.

Three points.

1. The frame demonstrably participates in the sound-producing system

You wrote:

“It is not and should not be a part of the acoustics → it is a structural reinforcement.”

But structural and acoustic are not mutually exclusive.

Ingolf Bork of Germany’s PTB actually measured this in a grand piano.

He identified a slowly decaying component around 90 Hz as a resonance of the iron frame. Importantly, he found that although the frame was not radiating that component directly, its vibration was transferred to the soundboard and then radiated acoustically.

So the measured chain was:

iron-frame resonance → soundboard vibration → radiated sound.

Even more interestingly, Bork reports that removing this low-frequency component from the sound at certain listening positions produced an unnaturally synthetic character.

That is experimental evidence, not a theory about what the frame “should” do.

Source: AES record — Bork, Sound Radiation from a Grand Piano
Open copy of the paper

2. Calling frame reflections “not the real sound” doesn’t solve the problem

You then argue that because the frame is hard metal, it reflects sound from the strings/soundboard and therefore “shifts the real sound”.

But why are those reflections automatically less real?

They occur inside the actual piano.

The strings, bridge, soundboard, frame, rim and lid form a coupled physical system. A microphone above the strings records the acoustic field that this complete instrument produces at that position.

If your objective is an anechoic recording, the anechoic chamber removes room reflections.

It does not somehow remove the internal acoustic and mechanical interactions of the piano itself.

So if you then cover the frame specifically to suppress those interactions, you are doing something different:

you are modifying the source.

That may sound better. It may make close-miking easier. It may be useful for a sample library.

All perfectly legitimate.

But it isn’t automatically a more “pure” recording of the original piano.

3. Recent research actually strengthens this distinction

There is now a 2026 study from researchers at the University of Southampton, Politecnico di Milano and Fazioli specifically titled “Cast-iron frame contributions to piano string vibration and sound radiation.”

Their coupled string–soundboard–frame model finds substantial force being transmitted into the iron frame and predicts that the frame can make a significant contribution to sound radiation, particularly in the treble.

Importantly, the authors themselves are careful: the final acoustic-radiation prediction still requires experimental validation.

So I wouldn’t present that modelling result as established measurement.

But it independently reinforces the thing Bork did measure experimentally decades earlier:

the iron frame is dynamically coupled into the piano system. It is not an acoustically nonexistent scaffolding that can simply be removed from the definition of “piano sound”.

Official open source: DAGA 2026 — Cast-iron frame contributions to piano string vibration and sound radiation

So I’d make the distinction very simple:

If you say “I prefer the sound after covering the frame”, fine.

That’s an experimentally testable production choice.

But:

“the frame is structural, therefore it should not be part of the acoustics”

doesn’t follow.

And if the stated objective is specifically to capture:

piano minus room

then the clean experiment is to remove the room while leaving the piano unchanged.

Once we remove the lid, cover the frame and otherwise alter the instrument’s own mechanical/acoustic behaviour, we’re no longer merely isolating the piano.

We’re designing a different dry source.

Which is what all our discussions eventually seem to be about. You need to build your own instrument.

@CyberGene dikrek (if real person) used AI bot, and it is plainly obvious.
Forums are getting bloated by the day. I do not like it. I am not here to teach AIs (they will "read" it anyways).
I am here to share ideas, not "established practices" as alleged facts or rules.

dikrek But there is no special transition at 200 Hz.

Oh, now we have to go on a tangent about low freq energy and how it eats up digital bits (headroom) of digital recordings when summed from signals (tracks) of various microphones. No. No time for that.

@CyberGene
Is there a forum policy about\against using AI in responses? As with your claude_user bot you could see how verbose it is and boring.

dikrek “phase alignment works below 200 Hz, becomes impossible above it, and two omnis pointing 180° apart are the worst case.”

Those specific claims don’t hold up.

This is total garbage. Omnis at 180°. Out of the blue "quotation" which I never wrote.
Phase alignment works mostly for freq up to 200Hz (and that is the upper limit, more likely up to 100Hz) → you cut them out (shelf them down) for sources (mics, pickups) that are not bass\low intended. And, yes above that "freq area" it is impossible to phase align two signals. And it is not necessary.

dikrek But physically rotating an omni microphone through 180° does not invert its polarity.

Ok, but also you place it in an acoustic environment not in vacuum of space or up in the sky. Every position change (not rotation!) means different early\late time reflections and for freq of below 200Hz that will result in phase shift.

F‑off AI.

dikrek But why are those reflections automatically less real?

They occur inside the actual piano.

Because that frame is only there because idiots in the past put more and more strings per key (note) to make piano louder in mid and upper range. That frame is not supposed to be a part of any sound reflections. But inevitably it is. It is of metal to support the increased tension pull. To make it less contributing (undesired contribution) to the sound it should be covered with fluff.

Imagine placing a metal frame over the top and strings of a violin just because it "has to be part of the construction to match that of a piano". Or on a guitar, or wind pipes. It is hard metal. Imagine entering in a wooden room and then in the same room but this time with metal beams and bolts and frames on the floor (ceiling). The acoustic sound will be a nightmare.