Could you please let me know if the Denon unit has fixed centers for the PEQ feature? After reading the specs, I got the impression that the bandwidth and gain were adjustable, but each of the 8 bands were at predetermined center frequencies. If so, this feature would be next to useless for true room/speaker correction.

And I agree with you about the need for good measurement tools. The use of a good RTA like "Real RTA" provides 1/24th octave analysis, which is critical to a successful result.

I use a separate Simetrix PEQ with the Outlaw 950 and am very satisfied; this will be much easier to employ with the 990's balanced outputs. Thank you in advance.

Allan

I don't believe this to be the case, no. I also don't believe that Kevin's statement about losing blacker than black with the 990's DVI switching is correct, since the switching is not directly affecting the signal at all.

DVD players that have DVI or HDMI outputs should be preserving the digital video data all the way through to the display. Most also convert the 480i video contained on the disc to 480p, 720p, or 1080i (some HDMI players support digital 480i output, but most don't). Whether it is better or not depends on how well the conversion is performed.

VGA is an analog format, whereas HDMI is digital only and the full DVI standard allows for either analog or digital (DVI was originally developed to connect PC's to LCD flat panel monitors, which are digital display devices.)

From what I understand, it depends largely on the source device being used. A good progessive scan player with component output to a good, properly calibrated display (particularly a CRT, which is an analog device) could yield results equal to a mediocre implementation of DVI or HDMI when connected to the same display. I'd recommend looking at your specific case, keeping in mind that at some point we are likely to see high definition video sources restricted to using digital video outputs (primarily HDMI when that day comes) - with analog component or VGA outputs restricted to a maximum resolution of 480p.

Allan,

The auto EQ does not have fixed center points, nor does it have fixed 'Q'. However, the manual EQ option has both fixed center points and fixed 'Q', allowing the user to select amount of boost/cut at each of the 8 fixed point frequencies (which are spaced 1 octave apart, starting at 63 Hz.

I found the auto EQ generally (I'm no expert, and have not spent too much time with this because it takes more than enough time to set up a decent HT and I prefer to use the time to affect tweaks that I know are valid ones) to be akin to a DSP matrix type of effect rather than a tool that 'corrects a room'.

I only compared auto to manual because I had the time and computer set up and was curious. I find the Denon manual all but useless. All things considered, I don't find the on-board digital PEQ of the Denon to be the right approach.

Again, I think Outlaw is right. DSP setup/parametric EQ is an idea that will eventually evolve into a great feature for an affordable price. Just not yet. Just my opinion.

There is no substitute for room treatment along with sub/sat placement angle and distance tweaks in a properly constructed room...before EQ. Auto EQ, to those uneducated on the subject, will give the false impression that it will fix the room, placement, etc.

Bosso

Gonk,

No wonder everyone here holds you in such high esteem. Thanks for your reply.

I'll ask your *opinion* on this, and accept your answer as that...

I have an Infocus 5700 front projector. It has the TI Matterhorn chip, 1024 x 576 (at 16:9) display (ie, not true HD), and a Faroudja DCDI processor (I can give you a link to the specs if you wish).

1. I've heard different opinions about which of the following would be better:
A) using a newer (than what I have with RGB outs) DVD player that scales the DVD to 480P and has a DVI output or
B) using my current setup and letting the Faroudja scaler upconvert the signal. The Bravo D2 from Vizio is the only one I seriously considered.

Part of the answer would seem to be whether or not the DVD player has a better scaler than the projector. The other part would seem to be that a DVI output from the DVD player *should* be more desirable than analog RGB outs.

DVI is an 8 bit pathway. HDMI is higher than that. I personally wouldn't assume that the switching in the 990 wouldn't discard that below black info. Someone should ask Outlaw. They should be able to find out.

This problem has been reported on AVS with players outputting HDMI then converted to DVI for the display. If the 990 has 8 bit digital switching for DVI, it's very unlikely that it'll pass higher res than that.

Actually RGB is a 8-bit pathway.

The Sil DVI chips (Tx/Rx) support three digital video data lines with data rates of 1.65 Gbps each regardless of the video stream bit depth.

The DVI chips used for Tx and Rx do not support color space conversion as the HDMI chips do.

The below black (and above white) problems on some DVD players and displays are caused by video processing before or after the DVI Tx/Rx chips.

Bosso wrote:
Yes, I did. I used a high quality measurement mic connected to my interface/computer vs. the optional Denon mic into the receiver, and tweaked the EQ manually, mostly for curiosity's sake.

Question: what software program etc... are you using to test and set up a HT with? Can you set up the system so that every seat is a sweet spot?

Bosso wrote:
Parametric EQ is a bandaid to fix the fact that the room isn't suited (placement/acoustic treatments/leaks/bad hardware, etc.) to a MC audio system. The majority of HTs out there are just a living room with hardware in it. Most of those enthusiasts have no clue how to employ an 8 band PEQ and Denon knows it.

Certainly, if you're one of the many who fit this category, the Denon receiver (a mid-fi, low powered MC receiver that uses bells and whistles to make up for it's sonic deficiencies, like Yammie, Onk, Sony, etc.) is for you.

Response: The Audyssey system is not a Parametric EQ system. See below.

I can not help but feel that some of your comments in your post are meant to be insulting and are combative.

In order to clear up one of your accusations regarding myself and others slamming the Outlaw 990.I feel compelled to state, that I have never slammed any product from any manufacturer, and never will, nor have I used wording like crap to describe a product. I understand the theory that one mans treasure is another's junk. I respect others and there product choices. If it sounds good to them, and they enjoy it that is what counts nothing else. I would not insult there choice. I fully intend on reviewing the 990 in my theater. I will at that time decide if the unit works for me or not, period. My statement that the 990 appears to be dated before it even hits the warehouse floor is not a slam, nor intended to be, just my feelings regarding it's current features

I will also add, that maybe Outlaw is waiting for Audyssey to release there new products in the very near future, and will at that point offer an upgrade. I don't know, only the powers that be in Outlaw know for sure.

Please find below some information about Audyssey Labs', and there Multi EQ program. Hopefully this information will clear up some of the confusion surrounding the Audyssey Multi EQ system.

Audyssey is a spin-off of USC’s Inmersive Audio Lab which Tom Holman (a Professor of Film Sound at the University of Southern California’s School of Cinema-Television and father of THX) and Chris Kyriakakis co-founded nine years ago. MultiEQ has been in the works for the last 5 or 6 years and is the result of Sunil Bharitkar's PhD thesis. Sunil was a doctoral student with Chris at USC and is a co-founder of Audyssey. Yes, Audyssey is a start-up, but this effort differs from most in that it has multi-million dollar funding backing it through an endowment from the National Science Foundation.

Below is a few excerpts from a few interviews with Tom Holman,and Chris Kyriakakiis.
an adjunct application to MultEQ intended for HTIB systems. It’s called PrevEQ. “The main problem with home theater-in-a-box systems is the huge hole between the sub and sat. With a HTIB system we would have the luxury of having the speaker systems in advance so we could pre-characterize the speakers and boost the subwoofer to make it go up higher in frequency (to match with the satellites).” Tom and Chris then both clarify that "the filter placed on the content side is 120Hz for Dolby and 80Hz for DTS which is a problem for movie theaters also.


“The approach to solving this problem in the past has been based on parametric EQ which is an extension of what was done with analog equalizers just, done digitally. The first problem is that you never have enough bands, typically 10, using an IIR (infinite impulse response) filter. IIR filters allow you to do things in the frequency domain but it does unknown things to the time domain. In many cases it manifests itself in ringing or smearing.”

“Our approach is based on FIR filters which in the past have been computationally intensive but this is not an issue any more because the DSP power has increased so dramatically. FIR filters allow us to correct the time domain and frequency domain at the same time. 'Well, you might say, FIR filters don’t give you enough resolution if you want to keep them relatively short.' And that’s true. This is the reason we implemented Dynamic Frequency Allocation (another of the imbedded technologies) which gives non-linear spacing. So instead of having only 80Hz or so resolution we can get down, at low frequencies (where it matters), to under 5Hz of resolution. It’s on a Bark Scale but the resolution starts below 5Hz at the lowest frequencies and goes up to a few tens of Hertz at 20KHz." (The Bark Scale ranges from 1 to 24 barks, corresponding to the first 24 critical bands of hearing. For computing all-pass transformations, it is preferable to optimize the all-pass fit to the inverse of the map, i.e. Barks vs. Hz, so that the mapping error will be measured in Barks versus Hz.)

The conversation now turned to the bottom line technology within MultEQ. The ability to have every seat be a good seat. Again Tom provided his historical perspective from tuning theaters in the early eighties. “While real-time analysis is ‘time-blind’ (so you have to know something about the time domain before you use it) nevertheless, if you clean it up, it has some advantages over the FFT-based analyzers. The THX R2 (from the eighties) was readily able to do spatial averaging and temporal averaging and we realized if we made an extension of it using a laptop with an add-on spectrum analyzer peripheral that we could send signals across dynamically from the analyzer and do a lot of mathematics to it and therefore clean up the signal."

[MultEQ]Chris takes over, “So part 1 was, we knew if you EQ for the single sweet spot then every other position would suffer from much poorer frequency response. (And that was one of the reasons for the bad name 1/3 rd octave equalizers were given.-Tom) Initially Denon and every other potential customer thought 'let’s have two modes'. One for a sole listener and one for when you have several listeners in a room. Well, it turns out if you EQ a whole room the audiophile seat gets better. If you take more of the problems of the room into account you’re fixing a bigger area than just the audiophile seat so there’s no need for two modes.”

Chris continues, “The approach other people have taken is to throw DSP at it. There are room correction units on the market that do just that. They can do 8000-tap FIRs and you need 3 DSPs per channel. But if you want to be in a consumer product you have to make some computing decisions. So that was the thinking that went into Audyssey’s Dynamic Frequency Allocation.

I then asked “Does it give the same response at each listening location? How is it possible, for instance, if you have a standard D’Apollito-style center channel which is known to have a lobe which points mostly toward the audiophile seat.” Chris responds, “By measuring the response at different locations we use a fuzzy-logic based clustering approach which, after computation, makes the sound at the audiophile seat better. The average assigns equal importance to each seat, an importance of 1. Now by applying a weighting factor automatically we use an approach based on pattern recognition. It doesn’t have anything to do with what we know about acoustics,” Chris stresses. "This is the leap of faith. It is the first application of fuzzy logic that I know of in audio.”

“If we were to treat the time domain version of these responses and say which of the criteria are closer to each other as far as pattern similarity, then I find for instance that seats 1, 3 and 5 in the room are "clustered" as far as similarity, seat 2 is by itself and seats 2 and 4 are similarly grouped together."

I interject and ask if the sound the system is reading is mainly direct sound and first order reflections and the answer was “No”. "The response that we’re taking is quite long. It’s 8000 samples over 200 milliseconds. If you look at the time response, it has a pattern. But if the seats have similar problems, they will fall into similar clusters as set up by our pattern recognition method. Where it gets fuzzy is that a particular seat can belong to more than one cluster. In other words, what it says is that based on our theory that seat #2 has 80% of the characteristics of seat #3 but 20% of the characteristics of seat #1. So there are no hard boundaries."

"So now we have six responses which we’ve clustered into 3 groups. From each response we elect a representative of the cluster. It’s not any one (exactly within the cluster), it’s one that represents each one in the cluster in the optimal way. That’s called a cluster centroid. So now, of the 3 clusters you have, you have 3 representative responses. So you do it again until you finally end up with the “President response” which represents the constituent responses in the optimal way. So the final representative response is the one we take and invert. When we invert we are inverting proportionally and non-linearly.”

Yes this Audyssey system is more complex and complete than the one currently found on the Lexicon piece. The Lexicon system only corrects for bass response while the Audyssey is full range, and uses FIR mulit taps. We have been researching this for quite awhile. Currently this is the most innovative and advanced room correction system in the industry.

I just found the "Secrets" article. Maybe this is part of the answer to my question:

" If you have a DVI source and DVI display, there will be no problem. If you have a DVI source and an HDMI display, again, no problem. If however, you have an HDMI source and a DVI display, the below-black video information may be lost in the translation. There is a bug in the Silicon Image HDMI transmitter that pops up when converting YCbCr to RGB"

So - if I use a DVD player with DVI and my Infocus projector with DVI I'm *OK*...
but -*should* that be an improvement on RGB coax w/ RCA connectors on both? I ask that because (back to the Secrets article and elsewhere posted in this thread): "DVD data are YCbCr, and are converted to RGB in the player for the DVI output. "(Notwithstanding quality issues of the DVD player or projector) (And, BTW, I will take no offense if anyone criticizes the Infocus unit)

Further reading of the article and posts here seem to tell me that HDMI is the only full digital method of transmitting the video without conversion to analog RGB - correct?

Also - the "Secrets" review of the OPPO Digital OPDV971H makes that DVD player sound pretty good for $200. Anyone had any experience with that unit?

RGB is not by definition analog in my understanding (although I could be wrong), so I don't think that the path from a DVD to a DVI output has to leave the digital domain to carry out the conversion from YCbCr to RGB.

The OPPO Digital did turn in an impressive set of scores on the Secrets shootout, but I don't know that many people had seen it prior to the shootout and what little I've read online indicates that most places have sold out of them. I am also a bit curious about the player or perhaps a future unit from OPPO. It's odd that the 971H will only output 480i on the component video output, making it primarily suited for those of us with DVI or HDMI inputs.

Ah... so conversion from YCbCr to RGB does not necessarily mean converting from digital to analog? Then moving up to a DVD player with a DVI out *might* offer better performance than component connections?