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FOR SALE: IPC Acoustic EQ Panels

Item #649440109
Info: IPC Acoustic EQ Panels

Asking Price:
USD $2500.00
Retail Price: USD $5000.00
Payment method: Cash, Paypal, Cheque, Money Order, Money Wire
Ships to: Canada, United States
Shipping weight: 22.68 (kg) Calculate Shipping
Condition: 9 - Excellent (?)
Date Posted: May 29, 18 8:45am (PST)
Edited: May 29, 18 8:47am
About Seller: PMC0607
Austin, TX
United States
[other classified ads]
Product Brand: IPC Acoustic Panels
Feedback Received: 21  See details
95.5% Positive Feedback
External Feedback: pmc (146)
Days in System:169
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Selling a lot of equipment for a friend that needs to thin out the collection. All equipment has been tested and it's operational.
Look me up in Audiogon under PMC and read my feedback. Any questions please text or call 512-731-7156 Pete
The Panels normally sale for $2,500 each asking $2,500 for both, Buyer to pay shipping and Paypal fees 3%

EQ Panels

Not too long after Clement and I completed our double-review of the IPC Acoustic Energizer (christened the “canister” by CP - reviewed here), my esteemed publisher asked me for my thoughts on a closely related IPC product, the EQ Acoustic Panel. So while this is in a sense a “follow-up” review, it is not really about the same product but, as far as I can tell, a completely and radically different one.

Semantics aside, perhaps a little chronology may be in order here. While I was reviewing the IPC Acoustic Energizer canisters (to recap, 2 of them in my room), Clement had already the good fortune of having four of the aforementioned IPC EQ panels sent to him for audition. So, even before the ink on my review of the canisters had dried, the fate of this review was already sealed. In short, if you only have time to read this far, the EQ panels are the best “accessory” I have ever tried in the last 20 years of my audiophile existence. And I have tried many. You may stop here now and go out to buy them.

For those who feel they need further and better particulars, here is the deal. The IPC EQ panels work on the same principle as the IPC canisters, but their effectiveness is multiplied several-fold. The design brief for the panels had huge acoustic spaces such as concert halls, theatres and recording studios in mind. As far as I can tell, the idea is to improve the coverage of the live sound and eliminate or reduce null points around the auditorium. Sound levels decrease by 6 dB for every doubling of distance it has to travel, but architects primarily tackle the problems of direct sound propagation by the sole criteria that it should not be blocked by other audience members. For an audience member who is seated furthest away from the source of the sound (usually the stage), assuming that overly long reverb times are adequately addressed (anything above 50 ms means a discrete echo, which is bad), the level and quality of the direct sound will be lower than for one seated closer to the stage. That is why we have seats that are priced differently. With judicious placement of EQ panels around the auditorium, I can certainly imagine this being a new and powerful tool in the acoustic engineers’ arsenal to bring about higher quality sound to the “cheap seats”. Oh dear, I hope this is not an excuse for concert halls to start charging more… enough said.

In my earlier review you can read about the designer Vian Li’s proprietary PVA technology. Vian Li was first driven to develop this technology while investigating why an 8” woofer sounded better in the same environment than a 12” woofer, even though the latter was measurably better. His conclusion was that the energy loss from the bigger woofer to the listener’s ear, through the air, was the main culprit. He reasoned that if he could minimize this loss, he would restore the true sonic potential of any sound system in any room. Solving the same problems in a public listening space poses even greater challenges, and the EQ panels were designed to meet these challenges.

Each panel measures about 53 x 1320 x 49 mm - (10" x 52" x 2"), and is quite unwieldy at 9 kg each. It looks like an elongated Chiclet and is covered from head to tail in an off-white acoustically-transparent cloth. They either hang off a supplied stand, reminiscent of those curved banana holders, or wall-hanging brackets. At the back, near the bottom, are 3 user controls; an on-off switch, a Damping and a Fine-Tuning knob. None of these can be intuitively used. The on-off switch may seem self-explanatory enough, but the local dealer informed me that the EQ panel actually does not run on electricity (whether AC or DC, unlike the AE units). There are no batteries to run down or change. It also continues working for up to half an hour after being switched off. Perhaps it absorbs and somehow magnifies and releases the signals physically presented to it? Again, as per the canister units, details are scarce. The Damping knob is supposed to increase or decrease the quantity of sound waves reflected by the panel, and the Fine-Tuning knob is meant to be used “by professional engineers” according to the manual, so it did not bother to elaborate further for non-professional engineers like me. I could almost hear the sniff.

Placing a pair of EQ panels in my room, for me, was a no brainer. As before, the corner placements of my AN-E/SpE/HE speakers preclude the EQ panels being located behind them. No other corners are available, and the side walls are taken up by my big Audio Reference monoblocks (one along each wall), and the rest of the equipment. The only space available was on either side of the loudspeakers. I tried using the panels in the first reflection positions in place of the usual RPG diffusors, but for some reason they did not work as well as when they were placed on the other side of the speakers, ie along the front wall. That’s where they stayed for the rest of my time reviewing them. Both Damping and Fine-Tuning knobs were set at the half-way mark and I never felt the need to experiment with them further.


We have all read reviews where a new product sounds like the equipment “got out of the way of the music”. To adopt the old chestnut, that’s exactly what the panels did. They vastly increased my sense of listening to no equipment at all, just music happening in mid-air, and with nothing between you and the music, much in the way a pair of extremely good headphones might sound. That it does this without being physically plugged into the existing system, or even being plugged in at all, makes it all the more remarkable.

The factors that add up to an almost uncanny sense of listening to headphones are myriad, but can probably be summarized into this one thing; low-level interstitial detail. Nowhere was this more forcefully brought to my attention than in the first of Schoenberg’s “Six Little Piano Pieces Opus 19”, played by James Boyk (Performance Recordings PR-4). Many audio systems let you hear a chord when the pianist presses down the keys, and the better ones let you hear when the pianist releases the chord. But what the EQ panels bring to the party is clarity on the timing of the release, so that you can hear that Boyk did not lift his left hand entirely, but finger by finger. You could - if you were anal retentive enough - literally identify exactly which key was released in what order (D natural and Eb, leaving G natural and B natural in place while he reaches over to play the ritardando figure in measure 11, and yes, I do have a life). It is not essential to have this level of detail to enjoy any piece of music of course, but having access to it enhances the illusion of the musician playing in front of you, giving your mind a much easier time.

When a wind player, such as a clarinetist plays, his fingers lift and close over keys and holes. A sound is fully formed within the clarinet when the fingers are properly in position and a column of air vibrates the reed and fills the instrument. However, in legato playing, in between each fully formed sound or note, there are many half tones, overtones, and harmonics in those micro-seconds when a pad or finger half-closes a hole. When you are able to hear these interstitial sounds in a recording, the clarinetist is right in front of you, right now, and for audio nerds like me that is downright exciting. Those who crave a more X-rated experience can put on their (insert your favorite sultry bedroom-voice vocalist) recording and be in the same room with (insert your favorite sultry bedroom-voice vocalist).

I don’t want to give the impression that the panels are all about retrieving copious amounts of detail. This they do, and very well indeed, but their other tricks are just as marvellous. As a whole sonic picture, the panels create that matchless transparency which sets a new benchmark for me. My previous system, which was housed in a different (larger) room, created a superb image with loads of detail, but I was only ever able to achieve a living, breathing, breath-taking lower-mid transparency with the best Reference Recording HDCD discs turned out by the legendary Dr Keith Johnson. Now, even with non-audiophile vinyl of some vintage, and the IPC EQ panels, I get that same KJ-signature transparency and coherency, not just in the lower mids, but right across the frequency range from lowest to highest notes. A case in point is the duet from “Norma” in Act 1 Scene 2 (Duets from Norma and Semiramide by Joan Sutherland and Marilyn Horne conducted by John Bonynge Decca SET456). One moment you are carried along by the pure, soaring, almost cinemascope bel canto lines, and the next moment without warning, the LSO kicks in with a fff diminished 7th chord that knocks you off your seat. The contrast in frequency, dynamics and texture is brilliant and supremely thrilling, reminding one why Bellini’s opera is often considered his masterpiece, and why only the most assured and technically gifted sopranos would even consider attempting the role.

Bass is especially well served by the panels, sounding effortlessly subterranean. It seems to erupt from the floor all around and underneath me, instead of rolling out from some predetermined space towards the listening position. Kettle-drum blasts in Darius Milhaud’s “Second Concerto for Two Pianos and Percussion” (Musical Heritage Society MHS 854) or Wolfgang Rihm’s “Sub-Kontur” (SWF-54 Ernest Bour conducting the Sinfonieorchester des Sudwestfunks) have never been a more visceral, full-bodied experience. Whatever the strengths of your system, the panels will multiply and enhance. Weaknesses are either ameliorated to a large extent, or left as they are. In business-speak, this is all upside, no downside. Quite how the panels achieve this is a Zen mystery, for how does an inanimate object decide what is good in a system and what isn’t? In a sense, isn’t that the ultimate, but rarely realized goal of every piece of hifi equipment ever made?


I could go on with example after musical example illustrating how good the EQ panel is, but that would just be gilding the lily. And what a lily this is. The EQ Acouztic panel is not cheap, but if you consider it not as a mere accessory but as a system component, which it truly is, it will seem like a bargain.

I feel I have to find something negative about the panel to justify my existence as a reviewer. Ok, it is big, heavy and has a very low WAF. And with a low- to mid-quality system, this panel may not seem to justify its asking price. But remember, it will grow with you. The better your system and room becomes, the better it will perform. Even if you own a room the size and quality of the Bayreuth Festspielhaus, you will never outgrow the panel (you just need more of them), so it is a purchase for a lifetime. You may get one and enjoy tremendous benefits therefrom, but a pair is de rigeur, IMHO. If you have the space and the wherewithal to do so, the more you get, the merrier you will be.

A postscript. My car has a reverse warning alarm mounted somewhere inside the vehicle, at the back of the cabin. While returning the EQ panels to the dealer, I shifted into reverse and started to back into a lot with the panels loaded up behind me. Suddenly, I heard a LOUD beeping sound which I hadn’t heard before, as if coming from somewhere next to me. For a few seconds I thought it was a new engine alarm, and flicked my eyes back and forth the dashboard, until I remembered my cargo, and checked… Yes, they were still switched “on.” I close my case.

This ad was originally posted on US Audio Mart US Audio Mart and the seller ships to Canada, and the United States.


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