StormAudio ISP.32 Mk2 / PA 8 Mk2 Cinema Pre-processor and Amplifier Review

Posted on 22nd April, 2021

StormAudio ISP.32 Mk2 / PA 8 Mk2 Cinema Pre-processor and Amplifier Review

Tony O'Brien enjoys the delicate sound of thunder with this formidable AV processor/power amp combination…


ISP.32 Mk2 Pre-processor, PA 8 Mark Mk2 Power Amplifier

PA8 MK2: AUD $13,999

French AV manufacturer Immersive Audio Technologies has caused quite a storm – if you pardon the pun – in the industry of late. Starting in 2010 as Storm Audio, the company worked on feedback technology for Class AB amplifiers. Two years later, it was acquired by Digital Media Solutions (DMS) and tasked with building the company's first residential processor. In 2015, DMS was acquired by Auro Technologies, and launched an integrated 13.1 AV receiver under the Auro Brand name…

Within another year, the team debuted its first platform-based processor, the ISP Mark1. The subsequent sale of Auro's hardware division in 2018 resulted in the formation of Immersive Audio Technologies, under which Storm Audio products are distributed. With a worldwide distribution model in place, Storm Audio's product distribution has skyrocketed. Its ISP Mark 1 and ISP Mark 2 processors have earned a slew of accolades and become the preferred choice for industry-revered acoustician Anthony Grimani.


While product take-up may have skyrocketed, the company's product portfolio is surprisingly light. Rather than producing a range of processors, there's just the one – the ISP Mark 2 – launched in 2020 to replace the Mark 1 – and two power amplifiers. The base model, the sixteen channel ISP.16 Mark 2, acts as a platform that can then be expanded upon by the customer or integrator. For instance, both 16-24 (ISP.24) and 16-32 (ISP.32) channel analogue out XLR upgrades are available, as is a 32 channel AES/EBU upgrade, 32 channel AVB upgrade and 16 channel DCI AES/EBU input upgrade. The latter makes it the only residential processor capable of playing 32 channel Atmos with a DSP package.

One of the key features of the ISP Mark 2, as Storm Audio Product Manager Sebastien Gailleton explains, is its modularity and stability. Hardware modules can be upgraded or expanded upon if and when needed. The ISP.32 will decode legacy codecs, in addition to Dolby Atmos, DTS: X Pro, Auro-3D, IMAX Enhanced and Sphere Audio for Headphones. While the ISP.32 is hardware- ready for the inevitable expansion to 32 channels, Dolby Atmos and DTS: X Pro is currently limited to 13.1.10, while Auro 3D (V2) is limited to 7.1.6. 

The ISP.32 is equipped with four ADI Sharc DSP 4 processors for post-processing and a single Texas Instruments K2G Processor for decoding – making a total of five DSPs. Decoupling the input and output DSPs is claimed to yield the lowest possible jitter and provide the cleanest signal path, allowing a greater level of subtlety and detail in the sound. Sebastian adds: “To us, neutrality is key. We are here to reveal the soundtracks, not to shape them to a specific sound aesthetic – which can be done via the Dirac tool with the target curve adjustment.” 

HDMI inputs comprise HDCP 2.2/HMDI 2.0B, 18Gbps with 4K UHD, HDR10, HLG, and Dolby Vision supported on all of its HDMI inputs and eARC on its two HDMI outputs. A new HDMI 2.1 board is slated for the end of 2021, bringing with it 4K/8K up to 48 Gbps up to 120 Hz, Dynamic HDR, Variable Refresh Rate (VRR), Auto Low Latency Mode (ALLM), Quick Frame Transport (QFT) and Quick Media Switching (QMS). The new board will be compatible with ISP Mark 2 processors in addition to Mark 1s. An upgrade for Dante 32 in and out is planned for the second quarter of 2021.

The ISP.32 Mark 2 offers manual calibration, with twenty point PEQ per channel via the Room EQ Wizard (REQ) plugin and automated calibration via Dirac Live 2.0 with Bass Control. Dirac offers different quality grades, mainly in the way filters are implemented within the processor, explains Sebastian. “We have the highest quality integration at the moment with 3,048 taps filters per channels, ensuring really accurate filter response.”

Dirac Bass Control adds subwoofer-to-subwoofer alignment, subwoofer-to-speaker alignment and speaker-to-speaker alignment, plus greater control over the difficult-to-tame crossover region. Dirac says this results in smoother bass than what's available with standard Dirac 2.0.

Expert Bass Management, available with manual calibration, brings the ability to add up to six independent bass zones, which let you match subwoofers to groups of speakers. For example, bass and LFE from the LCR channels can be routed to subwoofers in the front of the room, with bass and LFE from the side speakers directed to subwoofers on the matching sides of the room, and so on.


In addition to the ISP.32 Mk2 processor, Storm has two power amplifiers in its product portfolio; the PA 8 Mark 2 Ultra High Power (8 channel) and PA 16 Mark2 High Power (16 channel) power amplifiers. Both the PA 8 and PA 16 are equipped with Pascal Class D UMAC amplification modules. Asked about the choice of Class D over Class AB, Sebastien told me that both sound quality and integration were considerations. Having overcome initial drawbacks such as harshness and dryness, switching amplifiers now offer top-level performance, Sebastien contends.

Pascal UMAC Digital Amplifier modules were chosen for their reliability and sound characteristics, the latter being more in line with home cinema requirements such as neutrality and dynamics. Their high efficiency allows for 16 channel integration. Both amplifiers, he claims, are extremely powerful and quiet. Each offers up to 3kW of power capacity with instantaneous response, adapting in real-time to the demanding dynamics of cinema soundtrack reproduction.

The PA 8 Ultra High Power Amplifier is rated at a muscular 200W per channel into 8 ohms and 400W RMS into 4, with 0.1% THD, all channels driven. With four channels bridged, this number climbs to 800W. The PA 16 High Power Amplifier is rated at 200W per channel into 8 ohms and 225W RMS into 4 ohms, with 0.1% THD, all channels driven.


With obvious exceptions – such as HDMI components and amplifier modules – Storm Audio's products are manufactured in France. This fact isn't immediately apparent to the eye – as these products aren't exactly très chic. Yet, there's still an understated attractiveness to the ISP.32 Mark 2 Processor. Finished in matte black, the front panel provides little in the way of controls. In addition to a power button and volume control, three small buttons are available for menu navigation. Front and centre is a reasonably sized LCD display, while the silver Storm Audio logo is emblazoned on the left of the unit in silver.

Weighing 13.1 kg, it's a surprisingly easy lift despite its not inconsiderable 479x191x490mm dimensions. Needless to say, such a unit is more at home in a dedicated AV rack where it fills 4RU, rather than the AV Rack that the ISP.32 resided for the period of the review.

Make your way around the back, and it's soon apparent the ISP.32 is lovingly crafted and not the outcome of mass production. Connections are arranged in both a logical and modular fashion. The tiny screws next to the various modules (HDMI, XLR and so on) make them easy to replace. Our review sample was equipped with seven HDMI inputs and two HDMI outs, and no less than 32 balanced XLR analogue outputs are provided, accompanied by two XLR inputs and stereo downmix outputs. Legacy inputs consisted of four analogue RCA inputs, three digital coaxial and S/PDIF inputs, dual USB inputs, three analogue outputs, four 12V trigger outputs, two IR outputs and a LAN connection.

The ISP. 32 was double boxed, held securely in its box with black foam of the non-shedding variety. Other than a power cord, rack ears and user manual, the box was quite spartan; the most noticeable absence was remote control. That's because Storm Audio expects you'll be using a control system for the ISP.32, and as such drivers for Control 4, Crestron, Elan, RTI and Savant are available. I was pleasantly surprised to discover the ISP.32 was part of the Harmony Remote database, and worked flawlessly with my hub-based Harmony Elite.

If you're still not able to satisfy one of the above, all is not lost. Storm also has a remote app for android and iOS. Typing the IP address into a browser not only accesses the web GUI but a functional remote control. Be that as it may, even a basic remote would have been a very welcome inclusion, if for nothing more than setup.

Storm Audio's PA 8 (8 channel) Ultra High Power Class D power amplifier measures 435x150x49m and weighs 21kg. It's a modestly sized design, particularly when compared to its Class AB counterparts, thanks to its lack of need for extensive heat sinking. Finished in matt black, it is rather utilitarian in appearance; apart from the power button and logos, the only other thing adorning the PA8 is vents through which its cooling fans can be seen.

It offers eight balanced analogue inputs, with inputs one through four able to be bridged, along with inputs five through eight for a total of four bridged inputs. It also hosts dual 12V trigger outputs, one USB input and a LAN input. While most users will have the ISP.32 installed for them, I decided to forgo this step, letting me test the veracity of Storm Audio's claims that the ISP.32 is designed to be easy to set up.

For the most part, getting going is relatively straightforward for such a sophisticated product. Much effort has been put into the design of the user manual. Laid out in an easy to follow manner, its step-by-step style is easy to follow. And clearly marked connections on both the ISP.32 and PA8 Power Amplifier's XLR inputs make it a relatively straightforward process to connect both. The ability to assign any one of the channels to a particular speaker affords a level of flexibility and negates the need to reconnect things if mistakes are made.

At first glance, the web-based setup GUI appears daunting but is well laid out, the user manual doing an enviable job of explaining the process. YouTube also has several instructional setup webinars available should you need them. After assigning channels to speakers, I was prompted to create my first theatre. Diagrams helped me assign the bed layer, height layer and overhead layer for speakers. Here you'll also find the option to add multiple theatres.

For instance, theatre one could set up a full theatre room with Atmos speakers in one room, while theatre two operates a TV and 5.1 channel set up in another part of the house. Add to this the fact that both setups can be independently calibrated, and you've got not only a versatile but powerful solution – the only limitation being both theatres can't be used simultaneously.

When it comes to stereo listening, however, no such limitation exists. It is, therefore, possible to listen to radio or stream music in another part of the house while one of the theatres is in use. Once HDMI Matrixing is implemented, it will also be possible to watch what's being viewed in the theatre on another television without disturbing the theatre.

Sub theatres are another interesting feature, allowing a particular subset of speakers to be used within an existing theatre configuration. For instance, you could choose to use overhead Atmos speakers to add some ambient music to an environment or use the front speakers for dedicated stereo listening. 


Although a powerful tool, Dirac does come with a bit of a learning curve – especially if you're used to more automated systems like Audyssey. There's an app-based setup procedure for Dirac, though at this level, I urge you to use a laptop and external microphone rather than relying on your smartphone or tablet's microphone.

It's undoubtedly one of those cases of 'nothing ventured, nothing gained', as Dirac is one of the most potent but flexible room EQ systems available. Likewise, a bit of knowledge goes a long way, especially when it comes to ensuring room modes aren't boosted. As there's no microphone shipped with the ISP.32, you're going to need to source a microphone such as the Mini DSP's UMIK-1 or Dayton Audio UMM-6 – both of which are highly recommended.

After downloading Dirac Live, I had no difficulty locating the ISP.32 on my network and activating the full version of Dirac with bass management. With the calibration completed, you're given the option to either use Dirac's default curve, manual create a target curve, or download other target curves such as Harman's, which I did.

Likewise, it provides the option to group speakers to match one another's corrected frequency response and specify the range in which room correction is applied. While bass control performs a lot of its magic behind the scenes, tinkerers will be delighted with the extra control it brings. Once applied, it shows both the estimated response at the crossover and the crossover frequency window. Altering the crossover frequency displays the estimated response, giving users the ability to explore different crossovers and see the calculated response.

Dirac completed, it is usually a finished affair, as levels and delays, etc., cannot be altered after Dirac is applied. Uniquely, however, the ISP.32 allows the Dirac calibration to be copied to another slot, after which levels and delays can be altered, although it's not usually advisable to change delays with Bass Management applied. 

For my review purposes, the ISP.32 and PA8 Ultra Power Amplifier were connected to VAF Signature i91 front and centre speakers, four VAF i90s were used as rear surround and ceiling mounted Atmos speakers, with twin custom Veritas 10” subs rounding out a 5.2.2 Atmos layout. Video sources consisted of Panasonic UB9000 and Sony UBP-X700 4K Blu-ray players and Apple TV, connected directly to a Lumagen Radiance Pro; a Sony VPL-VW270ES projected images onto a Severtson 100” Cinegray 16.9 screen.


This is a potent combination. Capable of driving my speakers well beyond the threshold of what's advisable in my listening room, this dynamic duo created a gigantic sound field that was both bold and bracing. Bass response was impressive yet tightly controlled and superbly integrated with the main speakers. The pairs created an immense soundscape with a clean, abundantly detailed and transparent sound. For example, as Wolverine battled the Yakuza on top of a speeding bullet train in the DTS-HD Blu-ray of The Wolverine, this combo produced a massive sound field that engulfed my listening room. Traffic lights and signs whipped past the adversaries with a realism and force that brought me to the edge of my seat. 

While I often hear people saying that Class D amplifiers sound a little polite compared to Class AB, there were no such compunctions with the PA 8 Ultra-High Power Amplifier. Its ability to play cleanly often found me nudging the volume control and then flying out of the chair when the dynamics kicked in. The same was true in the Battle of Vindobona between the Romans and the Germanian tribesman on the DTS:X 4K Blu-ray of Gladiator. The Roman firepots' ferocity exploding in the trees was terrifying. Bass and LFE was tremendously impactful yet tightly controlled. As good as the Class G amplifiers of my JBL Synthesis SDR-35 AV Receiver are, they cannot match the power that the ISP Mark 2 and PA8 Ultra can bring to this worthy demo scene.

Indeed, the ISP.32 gave the DTS:X soundtrack a startling sense of clarity and detail, with transparency that I can't recall hearing from any other AV equipment. As Maximus made his speech to the calvary, I looked to the ISP.32 to see if it could impart the sound of a creaking tree overhead. I soon discovered that this creaking tree that I've listened to time and time again is actually the squawk of a forest board. It's a subtle difference, but one that speaks volumes about this system's transparency.

There's a wonderful sense of silence and lack of colouration to the sound. It not only lays bare the subtlest of detail, but untangles the often discordant mess of back tracks. For instance, during Netflix's A Series of Unfortunate Events, vocals were distinct yet naturally rendered, while instruments in the soundtrack were restored to their natural place. The experience is more akin to watching a stage performance with a backing orchestra.

As the Russian president entered the Polyarny naval base in Hunter Killer, the Atmos soundtrack sounded big, bold and cinematic. As torpedoes whizzed around the listening room, the ISP made great use of all of its loudspeakers, to guide them around with an excellent sense of directionality and space. Exhilarating stuff!


Storm Audio's ISP.32 Mark 2 and PA8 Mark2 Ultra High Power amplifiers must surely have been a labour of love for their creator. And as luck would have it, it's seemingly ongoing – evidenced by the fact that the ISP Mark 1 is both still upgradeable and expandable. 

Admirable as these features are, they don't count for much if the products don't sound the part – but that was not an issue here. Capable of producing a sonic storm, the sound field is wonderfully dynamic and powerful sound – truly cinematic. Yet, it's not just about brute strength, as this duo has a wonderfully transparent sound that reveals the subtlest of details. As such, this dynamic duo is an absolutely essential audition.

For more information visit Storm Audio


    Tony O'Brien's avatar

    Tony O'Brien

    As the owner of Adelaide based ‘Clarity Audio & Video Calibration’, Tony is a certified ISF Calibrator. Tony is an accomplished Audio-Visual reviewer specialising in theatre and visual products.

    Posted in:Home Theatre Amplifiers AV Receivers & Processors Power Amplifiers Applause Awards 2021
    Tags: cogworks  stormaudio 


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