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StormAudio ISP MK2 24CH AV Processor Review

by December 09, 2021
StormAudio ISP MK2

StormAudio ISP MK2

  • Product Name: ISP MK2
  • Manufacturer: StormAudio
  • Performance Rating: StarStarStarStarStar
  • Value Rating: StarStarStarStar
  • Review Date: December 09, 2021 00:30
  • MSRP: $ 24k (as configured)
StormAudio ISP MK2 24CH Processor Unboxing Overview
HDMI IN / OUT 
  •     7 IN / 2 OUT (ARC/eARC)
  •     HDMI2.0b/HDCP2.2
  •     4K UHD 18 Gbps on all ports
  •     HDR10, Dolby Vision, HLG
AUDIO OUTPUTS     
  •     16ch, 24ch or 32ch analog (XLR) - optional
  •     32ch digital (AES/EBU or AES67) - optional
  •     1x XLR Analog (Stereo downmix)

AUDIO INPUTS     

  •     16ch digital (AES/EBU) - optional
  •     4x RCA analog (7.1 or stereo)
  •     1x XLR analog (stereo)
  •     3x Coaxial SPDIF
  •     3x Optical Toslink

DECODING     

  •     24 decoding/upmixing channels
  •     Dolby Atmos, Auro-3D
  •      DTS:X Pro, IMAX Enhanced Ready
  •     All legacy codecs up to 192 kHz

PROCESSING     

  •     Up to 32ch
  •     Multi-theater & multi-room
  •     Multi-way speakers
  •     Multi-subwoofer
  •     20 PEQ per channel

ROOM CORRECTION     

  •     Dirac Live with Bass Control module
  •     REW plugin

STREAMING     

  •     ROON Ready

CONTROL     

  •     TCP/IP (ETHERNET), IR
  •     StormRemote iOS/Android Tablet and Smartphone Applications
  •     Web based configuration
  •     Control4, Crestron, RTI, Savant, ELAN drivers

Pros

  • Unrivaled Configuration Options
  • Best Bass Management and Routing We've Ever Seen
  • Digital Audio Outputs for Best Connection to Active Speakers
  • Upgradeable Architecture Ready for the Future

Cons

  • HDMI Currently Limited to 4K UHD (18GBPs)
  • No Analog Bypass
  • Complex Setup Process
  • Pricey

 

StormAudio ISP MK2 Introduction

StormAudio HeroBuilding the new Audioholics Smarthome provided me a unique opportunity to showcase the accumulation of the knowledge I’ve learned over the last 20+ years running this website. I wanted to build a theater room that not only surpassed the performance of the AH Showcase home built back in 2005, but also push the envelope of technology. I did my homework searching for an AV processor that had the advanced bass management facilities needed to not only support my RBH Sound SVTRS Active speaker system but also have a higher than 13 channel count to incorporate a conventional 7.2.4 system plus have the widest potential for future expandability. The StormAudio ISP Mk2 doesn’t come cheap at about $24k as configured for my unit. But, it does give you virtually limitless configuration options, including the most sophisticated bass management system I’ve ever seen in an AV processor. How does this all translate to the “ultimate home theater experience?” Read our review to find out.

ISP MK2 Design Overview

The StormAudio ISP MK2 is unlike a conventional AV processor from the big brands. It is not a single CPU PC type platform either. Instead, it’s a modular DSP based processor built around a preamp. The Control side (WebUI, TCP/IP…) is running on Linux and ARM platform, while the processing side is running realtime on DSPs (and other SOCs). Storm claims doing it this way ensure there is no possible interaction at the processing level between what happens in the control level and the content processing. This affords Storm incredible configuration flexibility and expandability that would otherwise be impossible to achieve. The ISP MK2 is one of two processors on the market that have the option to add a module for digital outputs. StormAudio offers 16CH, 24CH and 32CH variants of this platform via analog outputs or AES/EBU or AES67 optional digital inputs/outputs. With the ISP MK2, it is capable of processing up to 32 channels with 24 channels of native decoding. All three immersive surround formats (Dolby Atmos, DTS:X Pro and Auro 3D) are supported, with future firmware updates to also support IMAX Enhanced features that are now in the works. The Storm Processor can accept up to 192kHz/24 bit inputs, but does downconvert the sampling rate to 48kHz for post processing such as DIRAC Live and Bass Management.  Storm Audio supports the latest Dirac Live Bass Control module for multiple subwoofers and the state-of-the-art Storm Audio Expert Bass Management with its multiple bass zones definition and selective bass routing. IP AES67 and Dante network devices are supported as well, which makes this unit extremely flexible from an installer’s perspective. Imagine having the Processor rack mounted at a central location and having the power amplifiers local to each speaker connected and networked via Ethernet instead of long runs of line level cables. The ISP MK2 currently supports only HDMI 2.0b/HDCP2.2 (ARC and eARC) with 4K UHD 18Gbps on all ports (7 In / 2 Out). HDR10, Dolby Vision and HLG are supported. This product is Roon ready for those that want to take advantage of this slick streaming and music management software.

 

 Storm ISP Backpanel

StormAudio ISP MK2 Backpanel

The bass management facilities in the Storm Audio ISP MK2 are what really makes this product stand apart from its competition. The LFE and bass routing options are endless, enabling the end user to assemble a very sophisticated fully active loudspeaker system that can accommodate stereo bass, LFE and bass routed from other speakers set to “small,” while still having a dedicated subwoofer channel to supplement the bass for better modal distribution in the room. In my StormAudio ISP MK2 Bass Management Youtube video, I touch upon the basics of this bass management system to give you an idea, but suffice it to say, if you can envision a bass routing scenario you want in your theater system, Storm Audio will surely support it.

The Storm Audio ISP MK2 has provisions for multiple profiles that allow you to fully customize your speaker configuration, bass management, PEQ, and DIRAC. This is useful if you want to copy your current profile before running DIRAC so you can return to the original if you don’t like the post DIRAC calibration. It also enables you to switch between profiles for real time listening comparisons. If that’s not enough configurability for you, the Storm ISP MK2 also offers multiple preset options to save completely different processor configurations encompassing trigger control input configuration or completely different speaker layouts. You may want one profile to contain your theater configuration and associated speaker layout while a secondary profile is designed to play distributed audio from the in-ceiling speakers around your home.

ISP MK2 Setup

Last year I made the announcement that I was moving the family to the new Audioholics Smarthome we were building and documenting the entire process on our Youtube Channel to showcase the very best technologies to help our audience understand what is possible. I reserved the new dedicated theater room for the very best equipment we could put together to support a full-fledged 9.4.4 speaker layout (7 bed channels, 2 in-ceiling wides with angled baffles, 4 in-ceiling tops, 4 subs). The speakers and subs are all RBH Sound with the fully active DSP driven SVTRS speakers for the fronts and center channels. I wanted an AV processor that could accommodate this layout but also have future expandability. I also wanted the processor to have digital outputs for the front LCRs since I would be running the fully active RBH Sound SVTRS Speaker system. There were only two games in town to offer this flexibility, Trinnov being the other. I chose Storm Audio because I was really impressed with its bass management configuration and routing facilities. With the ISP MK2, I was able to configure my front towers as large, sum all small speakers’ bass and LFE to them and the other two powered subs in my system. Incredible!

With the help of our friends at HD2020, we built up my rack consisting of the Storm ISP MK2, Storm 24CH Class D amp, RBH Sound 8CH amp (powers front LCRs) Marani lpp-480f DSP for active FIR correction, Oppo UDP-205 (RIP Oppo), AppleTV 4K and Roku 4K, and Furman IT-Ref 20i and Elite 20pi Power conditioners to provide the clean and safe power from two dedicated 20A outlets. The speaker cables are 1313A Belden 10AWG high strand count cables along with their 1694 Beldon coax for RCA level, and 1800F balanced and Belden series-1 HDMI cables all furnished by Bluejeanscable.com.

remoteThe Storm ISP MK2 is the first AV processor I’ve ever reviewed that didn’t come with a remote control. Yes, you heard that right. If you want to control this product, you’re gonna have to either:

  1. Use your laptop on the same network
  2.  Download their App (Android and iPhone are supported)
  3.  Integrate the ISP MK2 into your control system
  4. A new option exists for 2021: You can order the remote for their Core-16 AV processor. The remote control allows for input selection, surround decoder select, info, volume, on/off and some other basic functions.

I used the first 3 options above to control my ISP MK2 and happy to report that I don’t miss having the stand-alone remote control. Let’s face it, most remote controls included with AV gear today are mediocre at best. Still, it's not a bad option to get their remote control as a backup in case any of the above 3 options aren't available for you while operating your ISP MK2 or if you want quick access to the IR codes to program your universal remote control.

Another thing absent in this processor is a GUI. This has become commonplace with many of today’s more sophisticated processors. Anthem and the Monoprice Monolith HTP-1 both lack a GUI. The Storm ISP MK2 does have a basic OSD that displays volume level, audio stream and input selected.

 Storm Remote App

StormAudio ISP MK2 Remote Control App

Before you freak out, I’m here to tell you I don’t miss those things. Despite being indoctrinated by those features from AV receivers, I adapted quickly thanks to the StormAudio Phone App available for Android and Apple and the driver for my Control4 automation system that lets me control basic functions (i.e. Input selection, volume, on/off). The App gives you full control of source, listening preset, preferred upmix (i.e. Auro, Dolby or DTS:X) with full adjustments (i.e. Center spread, sub level, etc) and other audio adjustments such as tone control, and zone control. The big thing missing from the phone App is the ability to adjust channel trims, delays and EQ function. Storm Audio feels speaker calibration is best done through the web editor and given the set up complexity they offer, I tend to agree.

Speaker configuration is the most elaborate I've ever encountered in a home theater processor. The graphical interface is very helpful in visualizing your speaker allocations.

AH Speaker Configuration

Audioholics Theater System Speaker Configuration Diagram on the StormAudio ISP MK2

As you can see, my layout is 9.1.0.4 ( 9 base, 1 sub CH, 0 heights, 4 tops). This is a very important step that I recommend you to triple check your speaker assignments are as intended BEFORE hitting the save button. Once you create a speaker profile, you cannot edit it. So, if you make a mistake now or plan on adding more channels in the future, you'll have to build a whole new speaker configuration.

Power Monitor

The Storm Audio unit has active monitoring on board to keep track of temperature, operational status and the incoming and post processed signals to verify what channels are active and IF their levels are undistorted or clipped. I found this feature extremely useful when evaluating immersive audio surround tracks to see which channels were active or inactive. I was surprised to see the wide channels utilized in a good majority of the Atmos content I was playing back and glad I installed them.

Calibration

filterFor the initial set up and listening tests in this review, I performed all manual calibration using REW to measure the in-room response of all of the speakers in order to design very precise PEQ filters to enter into the Storm ISP. Most of the optimization was done below the room transition frequency (<500Hz) with minor shelving filters (when needed) for the surrounds and center channel speaker. FIR correction was done via the Marani DSP for the Fronts and Center channels. I will reserve my testing of DIRAC for a future editorial and subsequent Youtube video to share those post calibration results with my manual ones to determine which one yielded better results. I used a laser to calculate precise distances for each speaker and the internal test tones with my measurement microphone to calibrate channel levels.

Two things that really blew my mind about the Storm Audio ISP MK2 were:

  1. The sophisticated bass management and routing options
  2. The precise PEQ filters

For once in my life, I am able to integrate truly full range towers to my system with proper bass routing. In this setup scenario I am routing bass from all channels set “small” + LFE to the main speakers and also routing that bass to two additional subs at the back of the room. The advantage here is the preservation of stereo bass for 2CH music for my main speakers while also taking advantage of the modal averaging of multi-sub playing LFE + mono mix to all bass sources strategically located throughout the room. To add icing on the cake, the PEQ function of the Storm ISP Mk2 is dead balls accurate. If I have a bump at say 25Hz 10Hz wide, simply entering a filter with Fc = 25Hz and Q = 2.5 to squash it works with surgical  precision-like accuracy. Best of all, I never ran out of PEQ filters for each channel since Storm Audio offers 20 per channel!

Listening Tests

Let’s start with music since at the end of the day, if you can’t do that right, then what’s the point from an Audioholics perspective? I do most of my music listening in the theater room by streaming via Apple Music or Tidal. I wanted to see how the various upmixers performed this duty in hopes that my properly calibrated 13CH speaker system could transcend the two-channel barrier.

The Storm ISP MK2 offers excellent adjustability for the upmixers including (center enhance, surround Enhance, sub enhance) which allow you to adjust the balance of sound. The Auromatic upmixer settings are more diverse than I’ve seen in other processors and you’ll want to experiment with room size and effect to taste. The Neural:X upmixer lack of center spread limits its usefulness for 2CH upmixing due to no fault of Storm Audio, but to DTS for releasing an upmixer not quite ready for prime time.

Dominique Fils-Aimé

DominiqueIf you don’t know who this fabulous singer is, you need to bookmark her on your streaming app of choice BEFORE continuing to read this review.  You will thank me later. Dominique is emerging to be of the great new artists of this decade. I absolutely adore the way she effortlessly merges multiple music genres whether it’s the blues sound of her debut album” Nameless,” or her jazz sound from her 2nd album, “Stay Tuned.” Her vocal layering is mesmerizing in tracks such as “Big Man Do Cry.” The percussion is so tight on this track and throwing this through the DSU expanded the soundfield sounded as if I was listening to a native Atmos soundtrack. Dominique’s vocals were anchored dead center like she was performing in my space while her layered vocal tracks were off towards the sidewalls, immersing me in harmonic bliss. I switched back and forth between upmixers and found the DSU gave a slightly better effect to the sides and behind me than Auromatic, but both sounded superb. The Neural:X upmixer is not worthy of such great music. It really botches 2CH music since it doesn’t have a “center spread” feature like the DSU or the previous DTS codec that had separate music and movie upmix modes. “Birds” is the first song I ever heard from Dominique and it’s as much of a treat today as it was the first time I heard it. I love the stand up bass in this track and because the recording is of such high fidelity, you can really hear all of the detail. While this sounds great in 2CH, its absolutely phenomenal upmixed with the DSU or Auromatic. The decay of the transients in the percussion surround you in a way I rarely ever hear from 2CH music. If you sit down your audiophile friends to listen and tell them this is a native Atmos track, they won’t know any better. It’s that good. The funk in “Sleepy” was laid out so thick it seduced me to just keep cranking up the volume. There’s nothing sleepy about the layering of Dominique’s voice in this track. This type of music not only sells speakers but makes you a fan as a side benefit. Go listen!

Billie Floyd 

Billie Eilish Happier than Ever in Atmos (left) ; Pink Floyd Dark Side of the Moon in 4.1CH (right)

Billie Eilish Happier than Ever in Dolby Atmos

Billie Eilish is absolutely killing it with her spatial audio mixes on Apple Music. Her latest album “Happier than Ever” is a masterful production. “I Didn’t Change My Number” may be my favorite song from this album. The bass, ooh yea, Billie and Finneas understand how to stimulate a bassaholic’s pleasure center. The sound effects toward the end of the song panning all around from above makes you realize installing Atmos was all worth the effort. I really get lost in “My Future” for the sentimental aspect of the song but also just the mix is so engaging to the senses. “Oxytocin” is the song you’ll want to crank up to showcase the bass capabilities of your system. With all my speakers going, the Storm ISP MK2 transported me into a nightclub, minus the claustrophobia. 

Pink Floyd – Darkside of the Moon DVD-A 4.1

I acquired a rare copy of this classic Pink Floyd album in 4.1 lossless. Normally I’d throw up in my mouth when I hear any track off this record due to a few decades’ worth of listener fatigue, but in multi-ch surround sound, it’s a whole new experience. The Storm Audio ISP MK2 did a superb job upmixing this album both with the DSU and Auromatic. I found it hard to pick a preference but suffice it to say, the height channels added good ambience. What an enjoyable experience to the senses being immersed with the bass thumping heartbeat and laugh track in “Speak to Me.” The speakers melted away within the first guitar and keyboard intro of “Breath.” Hearing the cash registers light up in “Money” all around me was a sonic delight. The bass line was so incredibly tight and the stereo effect of the guitars sounded incredibly dynamic and expansive. Thanks to the incredible imaging of my RBH SVTRS active speaker system, David Gilmour’s vocals sounded dead center in front of my like he was standing in the room. There’s so much going on in this track but the Storm Audio ISP MK2 just plays along effortlessly.

Unbroken UHD Blu-ray

UnbrokenThis movie, directed by Angelina Jolie, is criminally underrated. Perhaps I’m just a sucker for WWII movies, but there’s some great sound in this one. I must have watched the aerial scene where the USA bombs a Japanese factory a few dozen times, and I was continually in awe of the sound effects. Hearing the engines roar from the B-24 with the music score in the background was a great piece of cinematography that transformed my theater room into the war zone. The vocal intelligibility was crisp and clear even as the action light up ALL of my surround speakers with sounds of guns targeting the bomber. The wide channels really expanded the soundfield allowing me to visualize the airspace and size of the bomber. When the wing of Japanese A6M Zero’s came charging in, I really felt like I was part of the action. I couldn’t even imagine what this must have felt like being inside the Bomber with bullets flying all around you while essentially being a sitting duck, barely able to defend yourself. This was an impressive demo clip that truly showcases the wonders of Immersive Surround Sound when properly set up with excellent playback equipment.   

StormAudio ISP MK2 Measurements & Conclusion

 All measurements were conducted using our Audio Precision APx585 8 Channel HDMI Audio Analyzer following our rigid Amplifier Measurement Test Protocol

Frequency Response & Distortion

 
ISP MK2 Frequency Response

StormAudio ISP MK2 Frequency Response

The ISP MK2 downconverts all high sample rate input signals to 48kHz similar to what most processors do that employ room correction systems like DIRAC. What is interesting is that the ISP MK2 rolls off at 22kHz instead of 24kHz (1/2 sampling rate) indicating they are doing some additional processing that causes this.

ISP MK2 Bass HF noise 

StormAudio ISP MK2 Frequency Response with Bass Management Engaged

I observed some out of band noise at 30kHz (-70dB) and 50kHz (-55dB) with bass management engaged. Although this is inaudible, it is good housekeeping to clean this up. StormAudio told me this will be addressed with the new DAC design.

 

 ISP MK2 SINAD

StormAudio ISP MK2 SINAD vs Level (Volts) @ 1kHz

In effort to help our readers directly compare measured results on Audioholics and Audiosciencereview.com, I am starting to report SINAD figures which is basically the reciprocal of THD+N. The Storm ISP MK2 has lots of output drive and I was unable to make it clip even at max level with a 0dBFS input. The graph above shows SINAD and THD plotted on the Y-axis vs output drive in volts. We see between 91dB to 97dB depending on which channel is driven vs output. These are good results overall.

ISP MK2 Freq vs Distortion

StormAudio ISP MK2 Frequency Response vs Distortion

Update 12/13/21: A thread at ASR was brought to my attention discussing the above measurement with Amir and based on the comments there, I revisted and updated the text below.

The above sweep shows frequency response vs distortion which is exceedingly low at 0.002% THD+N (or 94dB SINAD). The distortion spikes above 5kHz are mostly due to a measurement anomaly caused by a combination of the down-sampling behavour, anti-aliasing filters and the fact that my measurement is wide bandwidth. It is likely so pronounced due to the high input sampling rate and the StormAudio ISP MK2 downsampling to 48Khz and not having usable output above 22kHz. I didn't see this many spikes when sampling at 48kHz but sadly I didn't save that measurement to replace the one above. It’s also still at 0.05% THD+N at 20kHz so still relatively low. I’d like to see better results here but an improvement may likely NOT be audible in most scenarios for even those audiophiles with the best of hearing. StormAudio has informed me a DAC upgrade is in the works slated for sometime in the near future with a possible higher sampling rate offered too. I will be revisiting these measurements once I get the upgrade module installed.

 ISP MK2 FFT

StormAudio ISP MK2 FFT Distortion @ 8Vrms 

The ISP MK2 maintained good composure when driven up to it output limits as shown in the FFT plot above. We see the 3rd order harmonic is 91dB below the fundamental, which is a very good result indeed.

An interesting observation is I was unable to ever clip the outputs of the ISP MK2 even with a 0dBFS input and the volume set to maximum which is why I wasn’t able to include a distortion vs output sweep like I typically do in our preamp reviews. Suffice it to say, this processor provides a clean 8Vrms via its balanced outputs.
 

ISP MK2 Square Wave 

StormAudio ISP MK2 Square Wave Response

I ran a 1kHz square wave into the ISP MK2 and found some under and overshoot. Ideally there'd be no overshoot or ringing like we are seeing in the curve above. This is likely due to the steep DAC filter settings StormAudio chose for this product for noise shaping. We don't listen to square waves so don't put too much concern in this result.

Signal to Noise Ratio and Dynamic Range (AES-17)

 

 ISP MK2 Dynamic Range

 StormAudio ISP MK2 SNR Analog output (Amode)

Note: Ignore channel 4 results as that's the subwoofer channel and this test was done at 1kHz which is out of band.

When I first got the ISP MK2 last year and did a series of measurements, the SNR results were NOT stellar for a product of this caliber. I worked with StormAudio to verify my measurements and as a result they prepared an updated beta firmware to improve the results. Since the ISP MK2 has both analog and digital preamp outputs, you can now select which type you are using for each output to yield the best performance. Configuring the analog outputs with this new optimized setting improved SNR 10dB. This is a very good measurement. The latest software release 4.1r2 contains this fix and you should upgrade if you’re running older firmware. I use both digital and analog outputs in my speaker configuration and they are both dead silent.

ISP MK2 XTalk

StormAudio ISP MK2 CH-CH Crosstalk

The two channels in purple and blue were configured for (A-mode, analog optimization) and ironically have higher CH-CH crosstalk than the other channels optimized for the digital outputs. Regardless, the CH-CH crosstalk with one channel undriven is excellent at -75dB @ 20kHz.

Bass Management

In my 20+ years of writing about audio equipment, I’ve never run across a more comprehensive bass management system than what StormAudio offers with their ISP MK2. I don’t think I will be able to articulate the full extent of its abilities here but will do my best to provide a sense of its power.

Bass MGMT Standard 

StormAudio ISP MK2 Standard Bass Management Mode

In standard mode, you see very similar bass management capabilities found in most AVRs and processors. I tested the typical bass management settings you’d use in a THX environment where the crossovers were set at 80Hz with a 2nd order Butterworth HPF for bass managed speakers and a 4th order Linkwitz-Riley LPF for the subwoofer with a 120Hz LPE for the LFE channel.

Bass MGMT THX 

StormAudio ISP MK2 Bass Management “Standard” Mode Frequency Response

I observed textbook filter response that would easily earn StormAudio THX approval if they sought the licensing for it. The HPF set for 80Hz (-3dB) measured a slope of 12dB/oct while the subwoofer measured 24dB/oct and -6dB at 80Hz. Bravo!

What separates the Storm ISP MK2 from virtually every other AV processor on the market is its almost infinite capabilities to route bass that is customized for your particular installation. For my setup, I’m running very large true full-range RBH Sound SVTRS Active towers that I wanted to route bass from all channels set to “small” and LFE to them in addition to sending the LFE to a 3rd sub at the back of the room. I was able to accomplish this in the ”expert” bass management setting using “Large and Sub” settings and by creating bass zones for the Left/Right channels and the additional subwoofer.

Expert Bass MGMT 

StormAudio ISP MK2 Expert Bass Management Mode

Using “Large and Sub” allowed me to run my main speakers full-range and also feed them bass from ALL speakers set to “small” plus LFE.  With most processors, you can’t run LFE to the main channels IF you also had a dedicated subwoofer channel. In such instances, the user would have to disable the subwoofer channel to route all bass to the mains. This typically causes overload conditions, which can cause digital clipping or simply too much bass. Is too much bass even possible for a Bassaholic? You betcha. The Storm ISP MK2 allowed me to scale down the bass summation from each channel fed back to the main Left/Right channels and also reduce the bass level from the main channels being fed to the dedicated sub to reduce the risk of overload or too much bass. This type of flexibility is what really helps an end user get great bass integration between their speakers and subs.

The ISP MK2 also has an internal test tone generator to help you calibrate via bandwidth limited or fullrange pink noise or external via REW measurement software. I used the external option so I could sweep each channel individually with the subs engaged to make sure I was getting optimal bass integration and level. While most processors are limited to 0.5dB increments in level and .1ft distance changes for speaker delays, StormAudio allows much finer adjustments. You can literally enter in the settings to the thousandths place. Incredible!

Bass Routing 

StormAudio ISP MK2 Bass Routing

Even when I played back the Dolby Atmos “Amaze” demo, which has the highest LFE bass content I’ve ever seen, I was unable to overload any of my subs either at the preamp level or at the speaker level, thanks to the proper scaling this processor enabled me to achieve.

 

Bass Management Expert 

StormAudio ISP MK2 Expert Mode Variable Bass Management

As you can see in the above graph, the ISP MK2 allows you to adjust crossover points and slope for each channel group individually. I was able to achieve this while also still having the proper bass summation, and filter slope going to the subwoofer channel.

I caution anyone wanting to run full-range speakers about the “Large with Sub” setting. I studied this and it still doesn’t make total sense to me. This mode does copy the bass from whatever channel group you set this to and sends it to the subs, BUT the actual channel group still gets a HPF applied. If you set your mains to “Large with Sub” it’s essentially similar to setting those speakers to small as you can see in the graph below. 

 

Bass Large w Sub 

StormAudio ISP MK2 Expert Mode Variable Bass Management “Large with Sub”

If you want your main speakers to be true full-range and want to route the main channel bass to your subs, use the “Large and Sub” option instead.

Downside

One would expect a product of this price caliber to have nothing to complain about, but then you wouldn’t be reading Audioholics if you didn’t want to see me whine about something, right? As good as the StormAudio ISP MK2 is, there are things I’d like to see improved upon. One minor strike against this product is it doesn’t currently support HDMI 2.1 which is likely only an issue if you're a gamer playing in 8K. This is to be expected as the bleeding edge with the latest HDMI chips are usually first implemented by the giants in the industry like Denon, Marantz, and Yamaha. They have a multi-tier production line of AV receivers and processors under development with higher purchasing procurement on parts and more resources at their disposal for quicker productization. StormAudio does have an upgrade path to HDMI 2.1 that we will learn more about next year. The Storm ISP MK2 currently doesn’t utilize a SOTA DAC section like you’d expect for a product of this price. While it’s not bad per se, it just doesn’t produce the best-in-class measurements we’d expect. StormAudio has a new DAC board in the works for 2022 that should bring the level of performance that will put a smile on my face when it produces impeccable bench test results. Let me be clear that I did not find the sound quality lacking in any of my listening tests with the current DAC implementation of this product. 

The StormAudio ISP MK2 is NOT without its operational hiccups. For example, I couldn’t play back DTS CD’s through HDMI with the current firmware at the time of this review but StormAudio told me this has been addressed in firmware ver 4.2r1 which I have yet to test. Prior to the firmware fix, the workaround was to connect toslink from my OPPO Blu-ray player to the ISP MK2 and switch to that input on the rare occasion when I still spin those discs. There have been issues where HDMI would lock up and I couldn't restore the picture or sound even with a power cycle. This mostly occurred when my laptop was plugged into the processor via HDMI for doing acoustical measurements with REW. I’ve had rare occasions where the unit would become unresponsive and I’d have to unplug the power to reset it. These are all livable issues to just be aware of, NOT to deter your consideration of integrating this product into your home theater.

Storm Speaker Config

StormAudio ISP MK2 Speaker Configuration Layout Diagram

Last but not least, the biggest Achille’s Heel for the ISP MK2 is by design, one I do not agree with StormAudio about. You are married to a speaker configuration once you set it. If you later decide to add an additional subwoofer channel or a pair of height channels, you must go back and do a completely new speaker configuration. If you plan ahead and add an extra subwoofer channel, DIRAC won’t let you run the calibration with unused channels present. While I can appreciate the reasoning StormAudio imposed this limitation to avoid the end user accidentally changing the speaker configuration, I hope they reconsider and allow pro installers the option of changing speaker configurations for the customer, perhaps in a hidden password protected submenu.

Another potential negative about the StormAudio ISP MK2 is that it doesn't have a analog bypass or phono preamp section. But to put things into prospective, many high end AV processors such as the Trinnov Altitude or Monolith HTP-1 don't either. Every signal that comes into the ISP MK2 must get digitized. This isn't a concern IF you're not spinning vinyl or playing back analog sources. It's possible StormAudio may introduce an analog direct mode in the future but for now, you're gonna have to have a separate analog preamp and phono section if you're a vinyl lover.

Conclusion

Storm Audio ISP MK2 heroThe StormAudio ISP MK2 is a technological marvel for cost-no-object AV processor. I am still in awe at the sophistication of its bass management system that can handle any type of speaker and subwoofer combination you could ever think to conceive. The speaker configurability ranges from modest all the way to SOTA 24-channel native immersive speaker layouts and up to 32 processed channels to build the very best large scale home theaters. The digital outputs allow the end user to integrate the bleeding edge in active speaker technology with a straight digital path to external processing with no analog to digital conversion like you would have with conventional processors.  This is such a big deal that I can’t overstate it. The end result is sonic perfection that enables you to build the system on your dreams rivaling the best cineplexes while also treating music with equal veracity. I like the fact that StormAudio builds this processor with upgradeability in mind (ie. HDMI 2.1, DTS Pro, etc). This ensures obsolescence won’t be an issue the way it is with most AV products that are not modular based like the ISP MK2. As much as I loved experiencing Dolby Atmos movies processed by the ISP MK2, the real treat for me was listening to Atmos music through Apple Music and Tidal. I felt that the ISP MK2 really let me dial in the “audiophile” in my system with all of the infinite adjustability that you just don’t get in a mass produced AV processor. Because of the level of configurability and associated performance I was able to achieve in my theater room, the StormAudio ISP MK2 is our 2021 Product of the Year Award winner in the AV Processor category.  I am looking forward to the future upgrades that will enhance the performance and features of this product and plan to continue on my home theater journey in the AH SmartHome with StormAudio at the helm.

2021 Product of Year

StormAudio ISP MK2

MSRP: $24k (as configured)

Contact StormAudio

The Score Card

The scoring below is based on each piece of equipment doing the duty it is designed for. The numbers are weighed heavily with respect to the individual cost of each unit, thus giving a rating roughly equal to:

Performance × Price Factor/Value = Rating

Audioholics.com note: The ratings indicated below are based on subjective listening and objective testing of the product in question. The rating scale is based on performance/value ratio. If you notice better performing products in future reviews that have lower numbers in certain areas, be aware that the value factor is most likely the culprit. Other Audioholics reviewers may rate products solely based on performance, and each reviewer has his/her own system for ratings.

Audioholics Rating Scale

  • StarStarStarStarStar — Excellent
  • StarStarStarStar — Very Good
  • StarStarStar — Good
  • StarStar — Fair
  • Star — Poor
MetricRating
Frequency Response LinearityStarStarStarStarStar
SNRStarStarStarStar
Bass ManagementStarStarStarStarStar
Build QualityStarStarStarStarStar
Fit and FinishStarStarStarStar
Ease of SetupStarStarStar
FeaturesStarStarStarStarStar
PerformanceStarStarStarStarStar
ValueStarStarStarStar
About the author:
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Gene manages this organization, establishes relations with manufacturers and keeps Audioholics a well oiled machine. His goal is to educate about home theater and develop more standards in the industry to eliminate consumer confusion clouded by industry snake oil.

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