No remote? Hell no.
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StormAudio ISP 16 MK2 Review (AV Processor)
- Thread starter amirm
- Start date
Active studio monitors have their own amplification, so you could plug them into the XLR outputs on the right of the unit when you look at the rear terminal.
Not sure about others, but in this price range I'd expect XLR connections rather than trying to cram an amplifier and speaker level outputs in as well.
OP
- Thread Starter
- #165
Definitely not correct. It is impossible for a machine to have non-linearities that manifest themselves at specific frequencies that way in THD+N. How would a system have harmonic distortion at 9.5 kHz but not 10 kHz? It can't.
The explanation lies in the fact that he used 192 kHz sampling rate for that measurement. That gives it a bandwidth of 96 kHz. So what the THD+N meter in Audio Precision is doing is taking all the noise, reconstruction filter error, noise-shaping, etc. and summing them all and reporting them as "THD+N." You may be familiar with similar test I run:
Anytime this happens, a diagnostic analysis must be performed to see if this really non-linearity or some other factor. This is why I follow with an FFT with the same bandwidth as above measurement:
We see our 1 kHz tone. It is then followed by harmonic distortion that decays as we would expect. Then we get a bunch of strong spikes up to -70 dB. These are caused by the DAC reconstruction filter not being strong enough to remove them. It has nothing to do with non-linearities in the audible band. We can see the response of Storm as Gene measured:
If you look to the right of 22 kHz, you see all those spikes that should not be there. But since they are ultrasonic in nature, they are not an audible concern. But, from measurement point of view, they get used in computation of wideband THD+N in Audio Precision with 90 kHz bandwidth. This is why you see the unusual spiky results in Gene's THD+N measurement. The energy here is not uniform so impacts some frequencies more than the other.
I was never a fan of this measurement due to this complexity. But eventually I added it due to so many requests for it but I always proceed with that FFT when there are issues. Gene should have done the same thing. It appears he is not aware of the important role bandwidth plays in computation of THD+N. This is evidenced by not noting strongly on the graph and in text what is going on as I do.
Conclusions
When I compute SINAD, I use a 1 kHz tone and harmonics of that are easily captured in the audible band (which is what I use in the dashboard). Computing SINAD/THD+N at frequencies above a few kHz is problematic because it includes ultrasonics which can including many things. Some of these things can be bad, but most of the time they are benign. And at any rate, do not indicate non-linearities and "distortion" in the classical sense of the term for THD+N/SINAD.
Care must be taken anytime THD+N has wide bandwidth to account for what doesn't make sense in THD+N measurements. Without it, the measurement is misleading as is the case here.
The explanation lies in the fact that he used 192 kHz sampling rate for that measurement. That gives it a bandwidth of 96 kHz. So what the THD+N meter in Audio Precision is doing is taking all the noise, reconstruction filter error, noise-shaping, etc. and summing them all and reporting them as "THD+N." You may be familiar with similar test I run:
Anytime this happens, a diagnostic analysis must be performed to see if this really non-linearity or some other factor. This is why I follow with an FFT with the same bandwidth as above measurement:
We see our 1 kHz tone. It is then followed by harmonic distortion that decays as we would expect. Then we get a bunch of strong spikes up to -70 dB. These are caused by the DAC reconstruction filter not being strong enough to remove them. It has nothing to do with non-linearities in the audible band. We can see the response of Storm as Gene measured:
If you look to the right of 22 kHz, you see all those spikes that should not be there. But since they are ultrasonic in nature, they are not an audible concern. But, from measurement point of view, they get used in computation of wideband THD+N in Audio Precision with 90 kHz bandwidth. This is why you see the unusual spiky results in Gene's THD+N measurement. The energy here is not uniform so impacts some frequencies more than the other.
I was never a fan of this measurement due to this complexity. But eventually I added it due to so many requests for it but I always proceed with that FFT when there are issues. Gene should have done the same thing. It appears he is not aware of the important role bandwidth plays in computation of THD+N. This is evidenced by not noting strongly on the graph and in text what is going on as I do.
Conclusions
When I compute SINAD, I use a 1 kHz tone and harmonics of that are easily captured in the audible band (which is what I use in the dashboard). Computing SINAD/THD+N at frequencies above a few kHz is problematic because it includes ultrasonics which can including many things. Some of these things can be bad, but most of the time they are benign. And at any rate, do not indicate non-linearities and "distortion" in the classical sense of the term for THD+N/SINAD.
Care must be taken anytime THD+N has wide bandwidth to account for what doesn't make sense in THD+N measurements. Without it, the measurement is misleading as is the case here.
Definitely not correct. It is impossible for a machine to have non-linearities that manifest themselves at specific frequencies that way in THD+N. How would a system have harmonic distortion at 9.5 kHz but not 10 kHz? It can't.
The explanation lies in the fact that he used 192 kHz sampling rate for that measurement. That gives it a bandwidth of 96 kHz. So what the THD+N meter in Audio Precision is doing is taking all the noise, reconstruction filter error, noise-shaping, etc. and summing them all and reporting them as "THD+N." You may be familiar with similar test I run:
Anytime this happens, a diagnostic analysis must be performed to see if this really non-linearity or some other factor. This is why I follow with an FFT with the same bandwidth as above measurement:
We see our 1 kHz tone. It is then followed by harmonic distortion that decays as we would expect. Then we get a bunch of strong spikes up to -70 dB. These are caused by the DAC reconstruction filter not being strong enough to remove them. It has nothing to do with non-linearities in the audible band. We can see the response of Storm as Gene measured:
If you look to the right of 22 kHz, you see all those spikes that should not be there. But since they are ultrasonic in nature, they are not an audible concern. But, from measurement point of view, they get used in computation of wideband THD+N in Audio Precision with 90 kHz bandwidth. This is why you see the unusual spiky results in Gene's THD+N measurement. The energy here is not uniform so impacts some frequencies more than the other.
I was never a fan of this measurement due to this complexity. But eventually I added it due to so many requests for it but I always proceed with that FFT when there are issues. Gene should have done the same thing. It appears he is not aware of the important role bandwidth plays in computation of THD+N. This is evidenced by not noting strongly on the graph and in text what is going on as I do.
Conclusions
When I compute SINAD, I use a 1 kHz tone and harmonics of that are easily captured in the audible band (which is what I use in the dashboard). Computing SINAD/THD+N at frequencies above a few kHz is problematic because it includes ultrasonics which can including many things. Some of these things can be bad, but most of the time they are benign. And at any rate, do not indicate non-linearities and "distortion" in the classical sense of the term for THD+N/SINAD.
Care must be taken anytime THD+N has wide bandwidth to account for what doesn't make sense in THD+N measurements. Without it, the measurement is misleading as is the case here.
The Audioholics 192kHz measurement appeasers to be showing noise at about -45 dB above 5 kHz and below 20 kHz.
That seems to be a problem, no?
- Rich
OP
- Thread Starter
- #167
No. That is what I was explaining!
StormAudio ISP MK2 24CH AV Processor Review
The StormAudio ISP MK2 24CH Atmos/DTS:X/Auro 3D AV processor has the most advanced bass management & connectivity features. Our review bench tests and listening impressions reveal why it’s our 2021 POY.
The AH measurements clearly shows spray in the audible range, it is not a THD calculation that includes account ultrasonic noise.
This may or may not be a problem in actual listening but (IMO) clearly should not be present in a $24,000 product.
- Rich
StormAudio ISP MK2 24CH AV Processor Review
The StormAudio ISP MK2 24CH Atmos/DTS:X/Auro 3D AV processor has the most advanced bass management & connectivity features. Our review bench tests and listening impressions reveal why it’s our 2021 POY.www.audioholics.com
The AH measurements clearly shows spray in the audible range, it is not a THD calculation that includes account ultrasonic noise.
This may or may not be a problem in actual listening but (IMO) clearly should not be present in a $24,000 product.
- Rich
I don't see it, and as Gene said it was only 0.05% at 20 kHz and that 0.05% would be made of harmonics mainly in the ultrasonic range. He said he did not see those spike if he used 48 kHz.
That measurement was done with 192 kHz sampling rate, I thought Amir was clear about that too in his post#165 but may be you just missed that?
The spikes shown, as I understand the graph, are THD. THD is calculated by the sum of the energies of the harmonics.StormAudio ISP MK2 24CH AV Processor Review
The StormAudio ISP MK2 24CH Atmos/DTS:X/Auro 3D AV processor has the most advanced bass management & connectivity features. Our review bench tests and listening impressions reveal why it’s our 2021 POY.
The AH measurements clearly shows spray in the audible range, it is not a THD calculation that includes account ultrasonic noise.
This may or may not be a problem in actual listening but (IMO) clearly should not be present in a $24,000 product.
- Rich
For example, the wide bandwidth THD of a 5 kHz signal will be the sum of the energies of 10, 15, 20, 25, 30, 35, ... kHz signals, divided by the energy of the fundamental.
For the Storm processor, its ultrasonic noise has a lot of relatively high amplitude spikes. When the AP calculates THD at a certain frequency, and some of those spikes happen to coincide with one (or more) of the harmonics, the THD calculation will include them, and thus cause a spike in the reported THD.
This is, I think, the origin of those spikes in the THD graph.
D
Deleted member 43441
Guest
This is a review and detailed measurements of the Storm Audio ISP 16 MK2 high-end Audio Video Processor (AVP). It was kindly loaned to me for testing and costs US $15,000.
This is one serious looking AV Processor:
View attachment 122657
As you see, it has a highly informative and detailed display. I will show more later. For now, the business end is in the back with various options it can be configured:
View attachment 122658
Where is a fan in the back, I don't recall hearing it over my normal equipment noise.
The ISP is targeted at custom installation (CI) market and it shows from not only myriad of triggering and automation but also incredibly well done web based user interface (protected through two levels of passwords). While the typical AV processor looks and feels like a mass market AVR with balanced outputs and no amps, the ISP goes to town, provide a level of control, sophistication and transparency into the device that I have not seen before. Clearly there is a ton of software that has been developed to manage this system. Here are some example screenshots:
Virtual remote control:
View attachment 122659
Triggers:
View attachment 122660
Status panel:
View attachment 122661
Love this real-time display of what the device is seeing. No more guessing as to why there is no sound coming out:
View attachment 122662
Most useful is the parametric EQ (in addition to automated DIRAC auto EQ):
View attachment 122663
Notice how it can even import filters from REW! All of this is implemented through the web interface so you can control it using any device yet the output looks professional like an "app."
Really, everybody else is competing to see who can get a score of C instead of D and Storm Audio ISP is relaxing with a score of A on the user interface and control!
Some background is in order. Storm was kind enough to send me this processor back in November of last year I think. They are the only high-end AV processor company to choose to do so. I tested the unit a few weeks later and found some performance issues. As is my common practice, when manufacturers send me something and I find problems, I provide feedback to them prior to publication. Sometimes this causes defensiveness on the part of the company. Not here. Storm immediately took the results in and worked on resolving the issues I had identified. They provided updated firmware to me for testing but by then, I was on to testing mountain of other gear. This went on until about a couple of weeks ago when I finally got around to testing and creating the results you see. Support from the company during this time was superb.
NOTE: since I had the unit here for so long, and because it was taking so much space, I already shipped my unit back to them a couple of days ago. So please don't ask me to test it more!
Storm ISP MK2 Measurements
As usual, we start with our dashboard which is created by my PC's Intel GPU generating the HDMI signal in 7.1 configuration but with two channels having output on them:
View attachment 122665
Distortion is at -102 dB or so (second harmonic) so with a bit of noise, the SINAD averages about 99 dB. Company measurements though showed better results:
View attachment 122666
Storm is using the HDMI output form the Audio Precision analyzer which tends to generate cleaner signals than my PC. Resolving this difference was hard so instead of sitting on this review for another six months, I decided to average their two channels and my two channels and arrive at a single number for the SINAD rating:
View attachment 122667
So definitely good and hanging with just a handful of competent AV processors out there.
The unit is of course capable of much more output:
View attachment 122669
As you see, there is a broad, optimal output voltage range going as high as 8 volts. So to the extent your power amp has better performance at higher input levels (e.g. Benchmark AHB2 and Purifi without input buffer), you could have a net benefit even though the ISP MK2 doesn't improve by itself.
Dynamic range is decent:
View attachment 122668
Linearity shows accuracy of 18 bits:
View attachment 122670
This is a limitation of an internal IC they are using. Jitter test shows very clean noise floor:
View attachment 122671
Very nice to see a proper reconstruction filter for 44.1 kHz as even high performance DACs often get this wrong:
View attachment 122672
IMD vs level shows classic "IMD hump" although I don't believe they use an ESS DAC:
View attachment 122673
Sweeping the frequency gives us the often seen, elevated noise+distortion:
View attachment 122674
As usual, we need to run an FFT to see the reason behind this:
View attachment 122675
We can see spikes well in ultrasonics that is causing this graph to look the way it does. Since they are not audible, this is strictly a measurement hygiene issue.
Multitone test shows 18 bits of distortion-free range:
View attachment 122676
Conclusions
I am usually hard core about just looking at performance of devices and not taking into account the functionality they provide. Here though, the company differentiates itself so much that I felt compelled to give them some extra points. Add excellent support to objective performance that is competent and you have the making of a device that should be in your sight if you can afford it.
I am happy to recommend the StormAudio ISP MKII. I applaud them for their drive to keep improving their products and spirit of collaboration they provided to me during this testing. For the first time, I thought if I needed an AV Processor, this is what I would like to have in my system!
------------
As always, questions, comments, recommendations, etc. are welcome.
Any donations are much appreciated using: https://www.audiosciencereview.com/forum/index.php?threads/how-to-support-audio-science-review.8150/
I know this is not a new review, but I appreciate it nevertheless.
Finally something worthy of the price tag, and although it is not cheap, I really like the simplified rear panel approach. Most of them are too cluttered, and half of them are afraid to get rid of the component inputs that hardly anyone uses.
Now we need somebody to do this for 5K to 7K.
Its unfortunate that the Core 16 is only about a 1/4 cheaper (DAC performance should be identical).
When news came out that they were going to release the limited 16 channel Core 16, I was guessing it would be at around 10K but it did come in at around $12k I think (could have even went up to $12,999).
How many channels are you intending to need?
tjcinnamon
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Does the Storm have anything similar to Audyssey where when the Master Volume decreases it bumps the Subs and Surrounds a bit more to get some mileage out of them?
No… Storm does not have any loudness compensation. I think it can be quite useful but have lived without it because of the very good bass, treble, brightness, sub level controls and surround level controls in the app
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Unfortunately lack of modern loudness comp is the only chink in Storm’s armor. I wonder if they’ll add Dolby’s new “Audio Processing” as Arcam/JBL and Anthem have.
That said, many (myself included) aren’t fans of DynamicEQ’s surround boost. HTP-1 changes spectral balance but not relative levels with changes in master level, and that seems to be the best approach.
Do you have a link to Dolby’s Audio Processing?
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Sorry, had to giggle a bit.
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This is all I know about it. I’ve never used it.
I liked its predecessor, Dolby Volume, but DV had separate loudness (modeler) and compressor (leveler) components. I don’t know you can have one without the other in the successor.
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