Well, after rereading James Johnston's PPT - http://www.aes.org/sections/pnw/ppt/room_correction.ppt

I kinda owe him an apology. There is some beef in there, I just accidentally skipped too far ahead and passed some of it (I was in the middle of plastering walls when I was trying to scan it for details). :o For those interested in looking at it, if you understand the basics of psychoacoustics, early reflections, etc, just skip ahead about 35 pages or else you'll get frustrated like I did. For JJ, I would simply recommend shortening that whole intro to something like "Since we know that......." and move right onto the meat and spend more time there.

I can only assume that Microsoft is considering delivering a room correction system to the masses via consumer electronics a la Audyssey, but don't know if this is a real working system, a software prototype or completely conceptual. But one of Audyssey's issues is that it has a hard time in any kind of noisy environment even doing the most basic things such as phase identification (and that always worries me). So I'm interested in what other people think of Microsoft's approach.

Other aspects I like has to do with how it treats treble much differently than lower frequencies, that it generates separate correction curves for different parts of the spectrum, that they appear to get the idea that you may not want to correct every speaker in the system, that it has a narrow band measurement for speaker setup.

A few questions/ideas I have are -

Does it make sense to correlate some data from matched pairs of speakers as they would be essentially identical except for the room?

Does it make sense to, alternately to going for a theoretical FR, allow the system to match center/surrounds to the main's FR.

Does it make sense to have a 'dial back' method to scale down the correction to, say, 70% if your ears say it goes too far in the right direction?

Does it make sense to tie the threshold for reflections somewhat directly to the frequency being measured, so that the correction window tapers off slowly into the midrange (or perhaps it does this)?

And, of course, how does the system deal with a speaker that is less than the direct/reflected threshold from wall?

And shouldn't there be a user selectable switch or threshold adjustment to tell the system if the speaker is in the gray zone or an inwall speaker?

For JJ, I would simply recommend shortening that whole intro to something like "Since we know that......." and move right onto the meat and spend more time there. Presumably JJ and his co-author tailored the content of the talk to a particular target audience. That you in particular may not need the intro material suggests that you don't fit the prototypical audience member. When I give academic talks I would love to sweep away the intro material, too, but I do not have that luxury.

The system is out already --- it's in Vista, which is admittedly not exactly turn-key consumer electronics.

--Andre

So that's the reason that a low end copy of Vista costs 200 F'ing dollars. Good to know that $29 computer speakers won't suffer so much ill effect from bad sounding rooms :rolleyes: Maybe they should actually focus some serious research into how to make reasonably priced software (as I type this from the superior Apple product........)

Oh well, so much for a potentially interesting thread!

Who's limiting PC's to $29 stereo computer speakers? Certainly nobody on this forum (http://www.avsforum.com/avs-vb/forumdisplay.php?f=26), or this thread in particular. (http://www.avsforum.com/avs-vb/showthread.php?t=713073) And heck, you're the one posted this on a high-end forum, but I'll bet that room correction capability will come in handy on this high-end HTPC (http://www.alienware.com/product_detail_pages/hems/hems_features.aspx) or oodles of cheaper DIY jobs.Oh well, so much for a potentially interesting thread!Now who's fault is that?

if you limit the correction to the PC, then you're limiting your source to computer and would largely obviate the use of other correction systems on board the audio gear. Of course, maybe they'll offer this up to others like HDCD, but it just seems weird to me to put advanced room correction into a computer rather than audio gear.

Keep in mind that the audio business just makes me a pessimist for some reason.

My high end gaming PC is hooked into my HT speaker system. No $29 dollar speakers here. Of course, I won't be running Vista in my HT until service pack 2 most likely. It is still way too unstable, plus the drivers don't work so well for audio and video still. The experimetal setup I ran had lots of audio stuttering issues, despite driver updates. I'm not really interested in running all of my source material through the PC either, but I would certainly turn on the room correction for computer gaming and Adobe Audition editing. :)

Sorry for any typos, I'm using the iPhone and I'm too lazy to correct everything...

That Alienware link looks like a promising HT server. When those start getting really good and cheap, plus have additional TBs of storage space, I may be interested in buying one. Unfortunately, it can't replace my gaming PC, so perhaps I'll just build my next gaming PC with a HT server in mind, which shouldn't be too far down the road, since these things are obsolete ten minutes after you build them. :(

Well, here's a more exciting development anyway -

http://www.foxnews.com/story/0,2933,327205,00.html

Gotta love railguns!

Only downside?

"Mr Scott, get the railguns back on line!"

"I canna capn, we've lost the main power!'

"How long?!?"

"I'm workin' as fast as I can but it'll take me 10 minutes"

"You've got 5!!"

http://www.foxnews.com/images/341194/1_61_railgun_test_1.jpg

Now, I bet that wasn't good for the environment...

I'm glad MS is interested in this stuff enough to hire really good people to implement room correction, but it also struck me as odd that a computer should be doing room correction. HTPCs are more a source component than some kind of switching device like a receiver or prepro, so not all devices in a system can take advantage of the room correction.

For silent HTPCs, I like this system for turn-key:

http://www.endpcnoise.com/cgi-bin/e/std/sku=spcr_quiet_core2.html

But for the next one I'll build, I'd copy this one:

http://www.silentpcreview.com/forums/viewtopic.php?t=41300

My current DIY HTPC is pretty quiet, but it doesn't do much computing as it's just a 4-channel PVR, and the MPEG encoding is done in hardware, so most of its cooling is done by 1 big case fan running slowly.

--Andre

i think it is pretty cool. since most of what i would want to watch/listen to is on a pc... why not have it do its thing then go to a 5/7 channel amp?

if you limit the correction to the PC, then you're limiting your source to computer and would largely obviate the use of other correction systems on board the audio gear. Of course, maybe they'll offer this up to others like HDCD, but it just seems weird to me to put advanced room correction into a computer rather than audio gear.

That may just be the Microsoft's game plan. The htpc taking over all source and prepro functions completely. htpc -> amps -> multichannel surround system (and htpc -> video display).

We've already seen input cards and external source switching (limited to 480i due to pci bandwidth) for the pc. High quality sound cards are already here. And there's Cablecard, internal hardware deinterlacing and software based deinterlacing. Growing processor speeds, multicore cpus, improved bandwidth due to pci-e, HD DVD and Bluray drives, and dropping hard drive prices coupled with increasing capacity all point to a future where the htpc might very well be an "almost in one" box. Think of Microsoft's history, of being successful integrating features into their OS, through innovation and acquistions. Could the future of audio/video be similar?

"Honey, we've got a blue screen of death on the projector, could you restart the computer again?"

Seriously though, it just seems like a waste of time and energy to develop room correction for a computer. People are increasingly going to laptops, they want computers for work/research, and actual dedicated machines for audio/video. Look at Sonos. In theory, no one needs that, you can do most of what it does with a PC, but it's a better appliance that happens to use computer technology, but isn't a computer and has a much better interface that people *enjoy*. There's nothing about HTPCs I find enjoyable to use.

Besides, computers couldn't possibly be more low-fi, from input to output. Unless you could keep the signal in the digital domain, I'm not seeing it for high-end use.

here is the thing, most (J6P) people want what is easy. that is a DVR, BD/HD DVD, and then extras. so being able to access movies on your PC, music on your PC is all gravy. If the MCE (or whatever) can do all this, it is extremely powerful to people.

WHile i will be buying my wife a laptop in the near future. i will be buying a PC for the living room.

Computers aren't even close to being as easy as separate gear. There will be no takeover by HTPCs any time in the next several decades. it's just kind of a cool thing. Apple is growing precisely because they understand that, while computers have lots of power, you need an appliance to make it easy and fun to use.

Heck, even Microsoft gets the appliance thing with X-Box.

For the computer oriented it will be nice , but I have to agree most people aren't computer literate enough to want to go through any of the tedious setup or troubleshooting issues involved in setting up a HTPC. That Alienware dedicated machine looks promising though. The people I know in my area only know how to use computersn for simple things, so almost complete automation of tasks is a must if you want large market infiltration.

How vista works today has no bearing on how things like my ATT UVERSE box integrate it internally.

And there are plenty of folks out there working to mak ethe PC a solid part of a living room. And personally i am all for it. does MCE have a long way to go??? YES. will microsoft ever come up with a UI that will be as easy to use as my old MOXI box??? NO. will somebody come up with a good skin app that will allow us to customize MCE or just select a great UI??? YES, of course.

Having this sort of functionality inside vista is a great idea. within ten years, the PC in some fashion WILL BE the centerpiece of most home entertainment. please note i said PC and not MCE. Sure there will be plenty of reasons to have a different DAC, or processor for many folks, but for most, it will be far more than they ever need. and the placement of XBOXes is merely the seeding of the network.

within ten years, the PC in some fashion WILL BE the centerpiece of most home entertainment. please note i said PC and not MCE.

"the centerpiece"? I accept your bet!

Good to know that today's technology will be useful in 10 years or so ;)

It also depends on how you define PC. Is it a PC as we know it today, or a PC hidden in something else, like the Apple TV? I really doubt the former becoming popular, but the latter is definitely very possible.

--Andre

most... not the denizens of this forum, but most. And likely in an appliance form of some sort.

http://www.foxnews.com/images/341194/1_61_railgun_test_1.jpg

Now, I bet that wasn't good for the environment...
QueueCumber,

Little environmental damage - you are mainly seeing EXTREMELY HOT air glow.
Some of the plastic parts are also vaporized - so you get some smoke. There's
less environmental damage than if some explosive or "gunpowder" were burned instead.

Some of my colleagues at Lawrence Livermore wrote the computer codes that the
Navy used to design this railgun:

https://www.llnl.gov/str/Nov07/white.html

Sharpe notes that ETM codes will be required to accurately simulate Office of Naval
Research railgun experiments. A railgun works by sending electric current along parallel
rails, creating an electromagnetic force so powerful it can fire a projectile at tremendous
speed. Future U.S. Navy ships may use stored electromagnetic energy to power
railgun-launched offensive and defensive weapons. Livermore researchers are also
interested in railguns as a possible technology for achieving velocities and pressures
beyond those of Livermore’s two-stage gas guns."

how long until there are personal hand held units?

http://www.vg.no/vg/96/anm/eraser2.jpg

most... not the denizens of this forum, but most. And likely in an appliance form of some sort.

Wait. An appliance or a PC? An Apple TV is an appliance. A Mac Mini is a computer. A PC is something that retains full computer functionality, whereas an appliance "applies" one or more specific capabilities to a particular task or tasks.

it will look like a reciever... but will be able to surf the web, get email, play online games, show powerpoint, access network drives for music, photos videos.

But will setup and configure much like an appliance.

But.....didn't you know that already happened, at least according to what people were saying 10 years ago?

"Will Microsoft deliver TacT type tech to cheap receivers?"

Is there some reason to think MS will do a better job than those in the audio industry?

I'm dying to see how the Trinnov room correction turns out in the Sherwood Newcastle receivers (latest ETA March or May).

"The Trinnov Optimizer: The $13,000 professional system comes home!
Until now, advanced room correction systems attempted to compensate for deficiencies and errors in loudspeaker frequency response
on a speaker-by-speaker basis. While somewhat effective, these methods made no effort to recreate the original performance.
Their intent was to smooth in-room speaker response.
The advanced mathematicians and acousticians who developed the Trinnov Optimizer took a larger view. They set out to recreate
the 3-dimensional soundfield of the original performance. In this endeavor, accurate channel-by-channel frequency response is only a
starting point. Trinnov’s task also required the ability to accurately measure and then relocate the apparent sound source until it was
identical to the original.
To accurately identify speaker response, placement and room modes, the Optimizer uses
a 4-capsule Acoustic Probe to measure the room and speaker systems in three dimensions,
reports the results, calculates appropriate playback filters and uses the calculated
digital IIR and FIR filters to optimize both speaker response and speaker
placement. The Optimizer can raise or lower the sonic location of an out of
plane speaker or shift the entire sound stage without relocating even a single
speaker. With Trinnov and Newcastle you can put the loudspeakers where
they fit, use the Optimizer to overcome the shortcomings of speaker placement,
speaker response and room interaction and still receive virtually perfect
imaging.
Performance graphs: System measurements made by the R-972 can be
saved to a USB drive. When that data is uploaded to Trinnov’s site, detailed
performance graphs can be viewed, evaluated and printed. There is no limit
to the number of times an R-972 owner can use this features.
Target Curves: Every room correction system must work to a target. On
the R-972, the original performance targets include: Laboratory flat, Audiophile,
Accurate and Front. When the filters to achieve these targets have been implemented,
the user can select to remap his speakers so they conform to either the ITU Standard for Surround
Music or the SMPTE Cinema Standard. These choices can even be stored by input making
it easy to assign the Audiophile target with ITU remapping for the CD input and to use the
Accurate target with SMPTE Cinema remapping for DVD’s."

Noah,

I agree. I have been following that thread as well.

Regards,
Will

QueueCumber,

Little environmental damage - you are mainly seeing EXTREMELY HOT air glow.
Some of the plastic parts are also vaporized - so you get some smoke. There's
less environmental damage than if some explosive or "gunpowder" were burned instead.

It is good for the environment?

Yeah, maybe you can buy some carbon credits every time it goes off :D

Is there some reason to think MS will do a better job than those in the audio industry?

Not necessarily as Audyssey doesn't talk much about how they do things. But there were a few things that made me think that it *could* be better. The Trinnov sounds like it might be playing god with the signal though. The problem with math geeks is that they do it by the numbers rather than taking into account psychoacoustics and subjectivity.

The problem with math geeks is that they do it by the numbers rather than taking into account psychoacoustics and subjectivity.

I thought that is how you liked it? :confused:

What you're doing with the room correction is making the signal inaccurate in hopes that the distortions in the room counter it in a way that makes the sound seem more accurate. That's kinda dangerous. With speakers, I've never said that a speaker measuring better makes it sound better to anyone, only that it has fewer serious problems about which to worry. But that doesn't mean you'll like it.

The problem with math geeks is that they do it by the numbers rather than taking into account psychoacoustics and subjectivity.That is, of course, nonsense, as any casual perusal of forums like HydrogenAudio will attest.

I kid you, but I was referring to how you follow that approach religiously with some parts of this hobby, such as speaker measurements. Of, course I realize these are completely different applications, which is where the joke comes in. ;)

There is nothing inherently wrong with corrective pre-distortion. It has a long history of successful application in audio, from LP preemphasis, tape noise reduction, equalization, mu-law encoding, and so on. Room correction is part of this same family. Yes it can be dangerous if wielded poorly but so what? Water is an essential nutrient but can kill you if you drink too much.

Water is an essential nutrient but can kill you if you drink too much.

And that my friends... is precisely why i drink either beer or wine!

That is, of course, nonsense, as any casual perusal of forums like HydrogenAudio will attest.

i'm exaggerating of course, but you know there's some truth to it! It's not enough just to measure well or be 'theoretically perfect'.

Audyssey - 'But there's only one correct answer'

me - "so you've tested Audyssey with every room, every system, every person?"

Audyssey - "Oh, well, I guess you have a point"

And don't forget "CD, perfect sound forever'

What was the company that said they don't listen to a product, they just design by the measurement, i assume so they don't let their biases in?

oh, and then there's THX speakers. Theoretically 'better', yet they all sucked pretty badly and were way overpriced.

In everything, you have to have part science and part subjective evaluation (hopefully also scientific). It's like people that think that FR accurate speakers sound badly. Well, they can, but it's not because of the accurate part. Lots of mistakes get made because either the math is wrong or the measurements used weren't sufficient to find the problem. That's why it also helps to listen.

Besides, wouldn't it be nice if a room correction program actually made recommendations for how to fix the problem acoustically first, then offered to correct it electronically if you couldn't? Like "hey dummy, your speaker is too close to a side wall" or "turn your damned bass down!" or something like that.

Well, we are getting closer and closer every day. You can buy a mother board today that has a HDMI 1.2a output on it. Yes, I know, no 1.3, but its a start. Further, it allows you output full 5.1 uncompressed sound, and not via the sometimes crappy digital coax. Further, it allows for a computer that needs less hardware (no video card) and thus less fans and other other jitter/sound generating devices. Adding a Solid state HD for the OS, and you really are cutting the sound level down, in the PC box. These are all baby steps towards a product that will offer greater levels of sound correction for the masses. If MSFT to charge another 100 for a MSFT branded mic, that will optimize sound quality.. its hard to believe they wouldn't. So, but by bit, we get a little closer.