Paul Merendino’s LCM modification

[Dizzie]

Precious little information in the post. What is the modification?

[HearYe]

Hello Dizzie,
I currently bypass the SL Bais Supply completely. I acheive lower ripple measurements and the sonic improvement is excellent. Here are some oscilliscope pictures displaying the ripple. There is also discussion on Facebook…

I make an Internal and an External model. The External model will allow a quick test to help you decide if you want to modify the OEM… Two connections are required, Yellor Bias and Ground. Simple and safe.
Here are a few pictures…

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[Massimo Stefanizzi]

@ Loudspeaker7:

excellent observation.
As with all modifications and improvements proposed over time by people who seem to get more enjoyment out of playing with their system than listening to music we should first ascertain whether these people who claim to hear huge differences and indisputable improvements are also able to recognize them 10 times out of 10 in a single-blind A-B test.

No offense or polemic intended: I have been working in this field (psychoacoustics) for 40 years and have witnessed remarkable cases of aural hallucinations in comparative tests of musical instruments.

[HearYe]

Hello Masimo,

Discovery of Asynchronous Bias Inter-Modulation (ABIM) in Multi-Panel Electrostatic Loudspeakers

1. Executive Summary

• The Paradigm Shift: High-end electrostatic loudspeakers (ESLs) are prized for transparency, yet residual soundstage veiling has historically been accepted as a room-interaction or recording limitation.

• The True Culprit: This paper identifies a previously unclassified form of distortion caused by the interaction of high-voltage switching bias ripples across unsynchronized, independent speaker panels.

• The Outcome: Eliminating this mechanism via a ultra-low-ripple, stabilized bias supply unlocks a quantum leap in soundstage depth, focus, and micro-detail retention.

2. Theoretical Framework & Root Cause Analysis

• The Baseline Mechanism: Electrostatic panels require a constant, ultra-high DC bias voltage to maintain a linear relationship between the audio signal voltage and diaphragm displacement.

• The Vulnerability (Voltage Ripple): Standard high-voltage switching bias supplies introduce macroscopic AC ripple voltage riding on top of the target DC bias.

• The Multi-Panel Interaction (Asynchrony): In systems utilizing multiple panels (left/right channels or discrete multi-element arrays), each panel operates on its own independent switching bias power supply.

• Frequency Drift: These independent power supplies operate at slightly different fundamental switching frequencies (\(\Delta f\)), which drift constantly due to component tolerances and thermal variance.

3. The Mechanics of ABIM Distortion

[Panel 1: Bias Freq A + Ripple] —\
–> Acoustic Mixing in Room –> Dynamic Phase Cancellation (ABIM)
[Panel 2: Bias Freq B + Ripple] —/

• Dynamic Inter-Modulation: The high-voltage ripple on Panel 1 modulates its primary electrostatic field, while the ripple on Panel 2 modulates its own field at a slightly different frequency.

• Stochastic Acoustic Cancellation: When the acoustic wavefronts meet in the listening space, these two unsynchronized modulation frequencies mix.

• The Veil Effect: Because the delta (\(\Delta f\)) is constantly shifting, it creates a unique, unrepeatable, and floating phase cancellation pattern. This microscopic acoustic turbulence destroys the absolute phase consistency required for true holographic imaging.

4. Engineering Solution: The Hear Ye LLC Approach

• Total Stabilization: Replacing the standard factory switching bias supplies with a highly filtered, ultra-low-ripple DC architecture.

• Neutralizing the Modulator: By suppressing the AC ripple to negligible levels, the mechanism driving the inter-modulation is entirely eliminated.

• Resulting Physics: With the modulation gone, the electrostatic fields across all panels remain perfectly constant and uniform. The acoustic wavefronts reconcile perfectly at the listening position without stochastic cancellation.

There is more… to be continued
Best regards

[Loudspeaker7]

Without accepting or not whether this problem exists, would not its potential for existing be eliminated in the new speakers that don’t plug into the wall and are self energizing?

[chungjh]

Guys, Paul Merendino designed a modification for Soundlab speakers. Paul kindly drove down from Ohio to Maryland to demo his modification on my system. I thought that my M545 couldn’t get any better, but installing his LCM on my speakers did something amazing. I am now hearing things that I didn’have. LCM eliminated annoying sibilance that has been bothering me and made the sound more clear and real. I recommend everyone to try it.

[Author]

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