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Messages - AndrewC

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3D Printing / Re: UV Resin 3D Printer
« on: Today at 08:50:39 »
Audio, whats your first project gonna be?

General Discussion / Re: Airport infection
« on: Today at 08:45:59 »
Finally, after they kenna exposed about all the incoming flights, they finally act (when its arguably already too late  ::) )

Can't believe they posted a "Fact Check" bloody essay over just one video  ::)

Earworm about Ecstasy  ;D

(OMG, check out that rack on the left of the dealer  :o )


Superficially, I think the ST2 Pro works rather well, both in terms of usability and functionally. I can imagine that for problematic rooms, or with mediocre systems, this thing probably does a fantastic job.

However, in a dedicated high-end 2-channel system with a properly conditioned room, I cannot in all honesty recommend that anyone puts the ST2 in the chain. While the unit can be configured to only correct low frequency responses, I don't trust it to not affect the rest of the audio spectrum (at least until I've had more time to test this thing thoroughly).

The one thing it did do well in my system was better separation. I'm pretty sure I know how to fix that passively in my room, but at the expense of room aesthetics (which I'm not going to do  ;D


PS: Sound on Sound has a good review of the ST2 Pro for an alternate perspective

*PPS: There's a 2nd hand ST2 HiFi going cheap on Carousell - I'm not connected to the seller in any way! I just happened to find it when I was benchmarking pricing before my Ebay purchase


It's been about 12 years since I last properly measured and fixed up my audio room. Took me a long time to get to the right mix of transparency, dynamics, holographic soundstage, and frequency extensions, both top and bottom - all the key attributes that most Audiophiles are always hunting for  ;D

My initial reaction with the ST2 Pro calibrated and engaged was "Wow!"... almost everything was different!

The most immediate noticeable differences were;
  • 1. Higher noise floor - though in a somewhat pleasant way, almost like "analog dither" behind the soundstage
  • 2. Much sharper "edge" to everything - almost to the point of being sibilant but not quite. Cymbals sounder more realistic, but voices sounder a little "HiFi" and somewhat unrealistic
  • 3. Better separation of the music elements across the soundstage
  • 4. Less "gut punch" bass
Here's the problem though; subjectively, only 3. was an improvement to how my room sounds without the ST2 Pro!! The rest were negatives, especially 2. as it was unpleasant rather like an over-sharpened photoshop image. I'm sure I can tweak the filter parameters to improve this though. Likewise for the bass, should be easily configurable by manually adjusting the amplitude correction.

When I attempted to do quick A/B comparisons by turning the room correction Off and On though, I was in for a little surprise;

The ST2 Pro allows you to click a button to bypass the correction function. The difference was quite startling! BUT, in bypass mode, my system sounded worse than without the ST2 in the chain! It initially took me by surprise to the point that I had to take the ST2 out of the chain to confirm that I wasn't remembering my system wrongly! (our auditory memory is shockingly short!)

[Screenshot of the Bypass mode]

Seems like the ST2 is doing something to the AES/EBU digital bits even when in bypass mode. The net consequence is that anyone who only does A/B comparisons with the ST2 in-place will naturally assume the difference is night & day in favour of room correction! :o

It's possible I might have missed something, I checked to ensure clocking was all in-sync and at the appropriate rates etc. But I don't think it's unreasonable to assume that bypass mode should be transparent. In any case, I plan to test this out again in my study.

The ST2 can operate in either the Analog or Digital domains. I only tested it in the Digital domain so far, inserting it between my CD Transport and my Upsampler.

The software setup is quite user-friendly, especially once you know the appropriate steps to go through; Trinnov's YouTube Videos are excellent in this regard.

The room measurement process, called "Calibration", consists of the ST2 issuing 3 short 3sec MLS stimulus signals on the Left speaker, followed by another 3 on the Right speaker, while their respective sound outputs are measured via the 3D mic positioned at the listening spot and connected to the ST2's 4 Analog-in XLR ports.

It then computes the necessary correction function, in both the frequency/amplitude, and time domains. It also provides information on the actual measured speaker placement vs. reference standards.

The ST2 can be configured to correct just Amplitudes based on the frequency response graph, similar to using an EQ (with up to 31 bands), or both Amplitudes and Phase correction, and Amplitude and Group delay correction!

The resulting filter function can even be edited by-hand if necessary, to tweak to taste, including configurable parameters for the FIR and IIR filters, even the length of the filter taps!

[Screenshot of the measured room Frequency and Impluse responses, before and after correction (1/12 Octave resolution, dBA - configurable from 1/3 to 1/48, and dBA or dBC)]

(the little spike at the 5.15ms point is I believe the room reflection off the unbroken long-wall across my left speaker).

[Screenshot of editing target correction curve - with a sample edit that I did not engage, all measurements/corrections were done with flat defaults across the board]

[Screenshot of FIR/IIR configurables, there're lots of parameters that can be tweaked]

I was actually just hunting for a spare digital cable on Ebay when I came across and ended up buying the Trinnov ST2 Pro at a steal (55% off retail, which I believe locally is about S$6,000)!!

This thing is designed for Mastering Studio use, for Speaker/Room correction of up to 4-channels. There's a Consumer version, the ST2 HiFi, which strangely is literally double the price, at about S$12,000 retail locally. Apparently the Pro unit is not available for purchase from the local Trinnov Dealers (not sure why), so you can only get the HiFi version locally*.

The main difference between the Pro and Consumer unit is that the Pro has only balanced XLR ports and Word Clock ports, whereas the Consumer version has a mix of single-ended RCA and balanced XLRs but no Word clock ports. Also the software frontend on the Consumer unit seems a little more user-friendly.

I intend to use the ST2 Pro in my (small) study, but gave it a spin on my main system over the last couple of days to see what it can do. So here's a somewhat mini-review.

The ST2 Pro is basically an off-the-shelf Compute platform with Audio I/O interfaces and specialised Trinnov proprietary Speaker/Room measurement & correction software.

The motherboard is a standard ASRock J4005B-ITX, with an Intel 2.7GHz Celeron Dual Core CPU and 8GB of RAM and all it's traditional ports; Ethernet, USB, PS2, and VGA, and can be connected with a keyboard, mouse and display, but the unit is generally accessed remotely over Ethernet though a VNC client.

Connected to the motherboard is Trinnov's proprietary Audio DSP board based on a TC-Applied Technologies' ARM-based TCD2220 Audio DSP chip, coupled to 2 Audio I/O interface boards; the ADA3 and AES4, for 8 x Analog balanced XLR ports (4-in/4-out) and 8 digital channels across 4 AES/EBU XLR stereo ports (2-in/2-out), and 2 x Word-Clock 75Ohm ports (1-in/1-out). The Audio DSP chip has a full "cross-bar router" feature which allows the routing of any channel to any channel, which the Trinnov software uses to full effect).

The unit is actively cooled with 2 internal fans, both virtually inaudible Noctuas, running at fairly low speeds, even when processing the correction function.

The 3D microphone is pretty cool, it's designed to "not only measure audio levels and arrival times but also direction, in both the horizontal and vertical planes". It actually consists of 4 individual spaced mics with their respective analog XLR outputs that you can connect to the ST2 Pro during measurement. Once done, it can be removed and those 4 ports used for analog audio I/O.

Here's a snapshot of the insides of the ST2 Pro;

Music Stuff / Re: History and theory of music
« on: 07 May, 2021, 15:09:00 pm »
History of Mercury Living Presence Documentary from the dCS folks;

Music Stuff / Re: What are you currently listening to?
« on: 07 May, 2021, 15:08:16 pm »
Thats an excellent track!! Gotta find it on redbook if I can!!  ;D

General Discussion / Re: 70%? Really?
« on: 07 May, 2021, 15:05:27 pm »

General Discussion / Re: The Anti PAP Thread
« on: 07 May, 2021, 15:04:03 pm »
Fucking cheebye PAP.... If this Video is for real, they're still streaming people into the country from CECA lands unabated, as of yesterday!!!!! WTF!!!!

EDIT: Looks like someone might be in trouble for taking that video yesterday at Changi :o

So, apparently the vid was form early May... BFD ... In early May the Virus was already ravaging the Indian Subcontinent, when our borders to them should have been well shut!!  >:(

General Discussion / Re: The Anti PAP Thread
« on: 07 May, 2021, 15:01:19 pm »
Real asshole. The fucker has the cheek even after completely destroying two companies. What a joke!!

I'm gonna find this asswipe on Facebook and send him (and CC: cheebye Loong) the following  ;D

General Discussion / Re: The Love PAP Thread
« on: 07 May, 2021, 14:55:47 pm »
 ;D ;D ;D

Home Theatre / Re: Zidoo UHD 3000 Media Player
« on: 06 May, 2021, 17:15:30 pm »
Not really.

Apparently some manufacturers are happy to violate the Roon/RAAT SDK license by implementing the stack in their system but then not getting it tested and certified. So, this forces those manufacturers to get tested and certified, at no cost to them I believe, they just need to supply the hardware.

General Discussion / Re: Funny stuff for the day
« on: 06 May, 2021, 17:11:18 pm »
If you imagined it would be impossible to advertise for both an Alcohol brand and a Mobile company together, guess again  ;D

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