Cirrus Room Correction in the New C3, HDP70, HDR77 Controllers

[Chris D]

I think this is going to become an emphasis discussion topic in the future, so I'll start a dedicated thread to it.

As mentioned in the other thread with info on the new upcoming controllers, they will not have Audyssey MultiEQ processing that is somewhat prevalent in today's market. Instead, the Parasound controllers will keep the auto-calibration capability of the previous models and now add new auto-EQ processing of some sort in the dual Cirrus DSP chips. I think lots of us are interested in what this will be able to do, and how it will perform. Will it "widen the sweet spot" for multiple viewing locations? Will it use parametric equalizers to flatten the room response, and if so, for how many sampling locations? 1? 2? up to 20-30 or whatever Audyssey can do as well?

So far, the most recent Cirrus performance product I could find was in a Sherwood Newcastle receiver in 2006, and it wasn't a lot of information. It looks like this will be a new production from Cirrus, or at least an evolution of previous Cirrus stuff.

Here's a Cirrus press release I found from Sanjay on another forum, 4 years old:

http://www.cirrus.com/en/press/releases/P426.html

Cirrus Logic's Intelligent Room Calibration Software Optimizes Audio Receiver System, Speaker Response for Ideal Sound Experience
Audio Leader Onkyo First to Incorporate Cirrus Logic's Intelligent Room Calibration Software into New A/V Receiver Products
TOKYO – Combined Exhibition of Advanced Technologies (CEATEC) Japan Conference – Oct. 5, 2004 – Cirrus Logic Inc. (Nasdaq: CRUS) has introduced advanced software into its dual-core audio DSP families that will enable consumers to quickly and easily attune their living room acoustics with their home theater or stereo system. This Cirrus Logic Intelligent Room Calibration (IRC) software, which is targeted toward mainstream audio/video receivers (AVRs) that typically sell for less than $1,000, will allow consumers to replicate the rich acoustical environment of venues such as state-of-the art movie theaters, concert halls and jazz clubs — all within about one minute.

The Cirrus Logic IRC technology includes two unique software algorithms: IRC Level 1 (speaker set-up software) and IRC Level 2 (room equalization software). These algorithms are available as an option with Cirrus Logic's flagship audio DSPs, the CS49500 and CS49400. Audio leader Onkyo has introduced two new AVRs featuring IRC Level 1 technology. The products are now available in North America (TX-SR602, TX-SR702) and Japan and have retail prices of $499 and $799, respectively.

"Through Cirrus Logic's IRC technology, consumers will be able to perfect their listening environment in their home, properly balancing out disruptions such as expansive tiled floors, mirrors, heavy carpeting, drapery and other architectural factors that can hinder the quality of the audio experience," said Tom Lee, vice president of Audio and Embedded Products Marketing, Cirrus Logic. "Also, in most home theater setups each speaker is typically not the same distance from the listener, when seated on their couch, recliner or favorite spot for enjoying their movies and music. The speaker set up feature in IRC Level 1 technology helps to get around this problem by optimizing the timing of sounds to the ear from the various speakers so that the ear perceives a smooth, natural progression of sound the way the audio mixers intended."

Cirrus Logic's IRC technology is designed to enable this automatic acoustic calibration feature on mass-market AVRs. Prior implementations of this capability by other companies are only available through a cumbersome manual process and only on AVR systems that can cost as much as $3,000-$5,000. Cirrus Logic has developed an advanced algorithm designed to render highly accurate results in significantly less time - a matter of seconds - compared with prior generations of competing technologies. Cirrus Logic's edge in delivering this robust consumer feature is the result of the company's strength in digital entertainment technology, as opposed to general-purpose silicon architectures offered by many competitors.

"Having a second DSP core on our CS49500 and CS49400 ICs allows Cirrus Logic's customers to feature the IRC technology and thereby differentiate their AVR products against their competition at similar price points," Lee explained.

Cirrus Logic's dual-core audio DSPs featuring IRC technology provide AVR manufacturers a scalable audio-optimized DSP solution that requires no additional hardware or board design changes. Further benefits include highly accurate sound quality and consistency of results when the calibration process is repeated.

How It Works

In a home theater setup, consumers will use a microphone, provided by the manufacturer, that is positioned in the room where viewing of home movies takes place. With a push of a button on the remote control, the Cirrus Logic IRC software sends test signals to different speakers in the room. The microphone captures the test signals and makes any necessary sound adjustments to the AVR's audio commands regarding the distance between speaker and listening position, loudness and frequency response of audio signals from each speaker. With Cirrus Logic's IRC Level 2 technology (room equalization) also featured, the system can be engaged to adjust audio frequencies from each channel on individual speakers (high-end home theater systems can feature up to eight channels of audio), thus giving the user a higher quality stereo or multichannel surround-sound experience.

"By focusing on ICs and software for the digital entertainment market, Cirrus Logic makes it easier for consumers to maximize their enjoyment of their stereo and home theater systems," Lee said. "And we're helping our customers introduce these great new features at more affordable mass-market prices."

[Chris D]

Here's a product bulletin on the same "Intelligent Room Correction" from Cirrus back in 2004:

http://www.cirrus.com/en/pubs/proBulletin/IRC_PB.pdf

Here's Cirrus' webpage showing all of their current DSP chips, with links to further data:

http://www.cirrus.com/en/products/pro/techs/T6.html

And here's the data sheet on the Cirrus DSP chip that looks like it best fits the stated specs of the new Parasound controllers. It's a revision of a chip first produced in early 2007. Don't know for sure if it's this one, or something else not listed on the site. Based on the info on the first page of the pdf file, though, I wouldn't be surprised if we're talking about the flagship DSP of CS4970x4:

http://www.cirrus.com/en/pubs/proDatasheet/CS4970x4_PP6.pdf

Now... if you look in this literature, which is the Cirrus product summary for 2008, you'll see at the bottom of page 23 that this DSP chip CS497004 (which is the only one that can do what Parasound is stating for the new controllers) lists a bunch of acronyms under the "firmware and features" column. Note that the last acronym is "PP2"--if you go to page 24 and 25, you'll see that this DSP is capable of a MASSIVE amount of AWESOME processing modes, and "PP2" actually does include Audyssey MultiEQ XT, THX Select2/Ultra2 Surround EX with Loudness Plus, Audistry, and Audyssey Dynamic EQ. :drool:

http://www.cirrus.com/en/pubs/misc/product_summary_2008.pdf

Okay, so I'm a dork for surfing for this junk. And I may be WAYYYYYY off base. And, I may be getting myself WAYYYY overly excited for something that we're not even really getting. Don't know. I'm just a dumb pilot. (glorified bus driver) :driver:

Go ahead and post any of your thoughts, or if you guys know something more that we don't!

[Eric Carroll]

Chris,

If you go a little further down on the thread you allude to elsewhere, you will see Sanjay posted a review of what is believed to be an update to the Cirrus room equalization system announced in the 2004 press release. My hypothesis at this time is there is a revision to the Cirrus PEQ system that will be visible in the Cary 11a, Parasound C3 and possibly Emotiva, all SSPs known to use the latest Cirrus DSP ( CS4970xx ).

As to Audyssey in the Cirrus, etc, don't get your hopes up. DSP manufacturers usually take code bases from the licensing companies (DTS, Dolby, Audyssey, etc), port them to their DSP architecture and make them available as kits on the DSP to OEMs. To enable these kits, you have to get the license, turn it on, and of course integrate the feature into your SSP.

For example, if you look at SSPs without THX, check their DSP and look at the datasheet, the DSP usually supports THX Ultra2 processing. This means the code is written and available, but just not enabled via the licenses in that SSP (and thus not integrated as a feature option). Note this comment at the end of the datasheet:

The external program code may be encrypted by the programmer to protect any intellectual property it may contain.
A secret, customer-specific key is used to encrypt the program code that is to be stored external to the device

In the data sheet you posted, Cirrus lists the "application libraries" - these are the decoders supported and could be license keyed per decoder. Note features like THX, HDCD, DSD, etc all have application libraries. But not all SSP manufacturers that have these options available with licenses and/or have integrated them.

Now, if the C3 really did enable Audyssey, that would be extremely exciting. But I suspect it will not since they have announced only the Cirrus PEQ solution, which we speculate is a less ugly implementation of PEQ that was in the Cary 11.

Also note in the data sheet the magic phrase "11 band parametric EQ". That's the frequency domain only PEQ capability. PEQ is (limited) frequency domain correction. Audyssey style correction is frequency, time and phase domain correction with a precision that depends on version and amount of DSP available to it.

The point is that the Parasound C3 (and others) could support THX Ultra2 and Audyssey if they choose to (and have enough DSPs in the design - 2 might not be enough). But they have chosen not to.

[Chris D]

Hey, Eric, welcome to the Guide and Club Parasound! :banana:

Thanks for posting all the good gouge. I KNEW there was somebody out there much smarter than me on all this stuff! :T

It doesn't surprise me that in order to fully unlock the DSP chips' potentials, manufacturers have to go through full licensing and implementation. I can only imagine what kind of headaches that creates for guys trying to create good products.

We'll keep our fingers crossed for a good EQ product in all these new processors that you mention!

[Eric Carroll]

Chris,

A comment on the "other forum" from a Reputable Source suggests that Audessey has not yet been ported to the Cirrus DSP. Thus the lack of a full blown Room EQ system on the vendors using this chipset.

[Chris D]

Thanks, Eric! Keep us updated with what you find out!

[Eric Carroll]

As to Audyssey in the Cirrus, etc, don't get your hopes up.

I get to eat my words. Audyssey announced on the C3 - very exciting.