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Discussion Starter · #1 ·
Hi Wayne,


Check out this thread http://www.avsforum.com/ubb/Forum3/HTML/005149.html


There seems to be some confusion regarding the Yamahas. You might want to contact Gary Merson and find out how(where) he got his information about the Yamaha only having 20Mhz. There was an old thread about this and Gary said he was going to test the Yamaha himself. If you find out anything more let us know. It does seem like the receiver manufacturers are paying more attention to this issue with their newer models. Good luck.


Jay
 

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Yes, I'm familiar with Gary's opinions and the article you mention.

And I'll take Yamaha's stated specs on their website. http://www.avsforum.com/ubb/wink.gif


quote from: http://www.avsforum.com/ubb/Forum17/HTML/000069-2.html

________________________________

Also, I have been reading and hearing mixed things about the 5800 being able to pass through a HDTV signal. Would you please clarify?


Thanks!

War-

________________________________


Thanks for the questions.


1. DPL2 "built-in" an off-the-shelf Denon: Sorry, I am unable to comment on future product introductions.


2. HDTV pass-through - OK, you asked, so here goes (this won't be a short reply).....


Late last year, the various A/V forums exploded with reports from various quarters about whether or not an A/V receiver/component could or could not pass HDTV signals. This question has never been resolved to anybody's satisfaction, in my opinion, and I don't think I'm going to be able to do it here, but nonetheless:


This all started with a report by Gary Merson about the *calculated* bandwidth necessary to cleanly pass an HDTV signal. Gary consulted with a number of DTV experts, who all came up with different MHz bandwidth requirements. Gary settled on 30 MHz as the minimum flat bandwidth necessary for a device to pass HDTV signals (720p or 1080i, the bandwidth is not exactly the same for both, but they are close).


The key word in Gary's report is *calculated*. Gary said quite clearly that his report was based upon a calculation, and NOT on actual testing using calibrated HDTV signal generating equipment and subsequent calibrated HDTV signal measuring equipment. Such equipment costs in the tens of thousands of dollars. I know of no publication, reviewer or consumer testing authority in North America (who is not a manufacturer or manufacturer consultant) that has in-house the necessary equipment to accurately test and verify HDTV bandwidth in an A/V component or external switcher.


Gary contacted a number of A/V receiver manufacturers, including Denon, and inquired as to their component video switching bandwidth. He got back a variety of bandwidth figures. This is where things got *very* interesting.


There are two ways that an A/V receiver can switch video signals. By far, the most popular configuration involves some sort of video switching IC. As a result, there will be a certain upper frequency limit in such devices, where response at the extreme high frequencies begins to drop (roll-off). Almost all of the AVRs listed in Gary's report are configured this way, and as you can imagine, this method is the most popular because it is also the least expensive to implement.


The other way is to do it via some sort of mechanical (completely passive) switching, involving relays. This is more expensive to implement compared to using video switching ICs. Only 3 of the A/V components listed in Gary's report incorporate component video switching via relays, all three of them are top-line models, one of them is the Denon AVR-5800. We spec it at 50 MHz, -3 dB, which Gary pronounced as sufficient to meet his *calculated* criteria for clean HDTV pass-through.


Denon's other AVR models that feature component video switching (such as AVR-5700, AVR-4800, AVR-3300, AVR-3801) accomplish this via the aforementioned video switching IC configuration, which has an upper bandwidth limitation of just below 30 MHz, the actual number derived being a function of how many dB of roll-off, etc. According to our factory, the part we use is also widely used in other brands of A/V receiver. We quoted a spec of 27 MHz at -3 dB to Gary for these models, a figure we obtained from our engineers at the factory.


I cannot predict how the other manufacturers who also answered Gary's inquiries arrived at their figures. But, from reading his report, a number of brands/models of A/V receiver that use the same video switching ICs that we use quoted different bandwidth numbers. However, most were very similar if not identical to our quoted spec.


In one case, a competitor's product that made it into Gary's report, which also featured relay component video switching (not IC-based), had a substantially lower reported bandwidth than ours (again, Gary says he got the numbers right from the various manufacturers). I spoke with Gary about this at the time, and we agreed that something wasn't quite right.


Gary arranged for a colleague of his, who had a suitable multi-burst test generator (not full HDTV capable, but high enough to get to the 24-25 MHz range) and a suitable waveform monitor, to lug the equipment over to Gary's place, and Gary also arranged to get a couple of loaner A/V receivers to try out. We agreed to provide Gary with an AVR-5800 for his tests. Gary graciously invited me to come along and have a look-see (or, did I invite myself? hmmm...). Anyway, I showed up at Gary's place with an AVR-5800 for him to test.


As the test equipment at hand couldn't go to 50 MHz (only roughly half that), Gary couldn't truly verify our AVR-5800 spec. But, he could see that the measurements showed the essentially "flat" frequency response he was looking for, again within the limitations of the test equipment at hand.


I watched as Gary tested the other model, the one which also had relay switching, but had been quoted by the manufacturer at 20 MHz, -3 dB. I couldn't see any reason why this should be so low, so out of purely professional curiosity, I stayed around while Gary did the same test. Of course, it wasn't such a bad performer after all, it provided (as I expected it would) very similar (and quite acceptable) frequency response compared to the AVR-5800, again, within the limitations of the test equipment at hand.


In my opinion, Gary's limited tests could not properly convey the true HDTV pass-through behavior of a particular A/V receiver. And, as we saw for ourselves, even a specification obtained directly from the manufacturer (Gary did not get his data off spec sheets, he called the various manufacturers directly), provided no true/real indication of the product's ability or inability in this regard.


Denon's A/V receivers that feature component video switching via ICs can and do pass both 720p and 1080i program material. However, and this is a very important qualifier, the ultimate "transparency" of the pass-through is a direct function of 2 things:


1. The quality of the HDTV signal source - DTV set top boxes are not all the same, and the 720p and 1080i upper frequency response of these devices is not the same, there are differences in the video DACs, and subsequent analog post-filtering and analog video output stages, just as there are with 480p progressive scan DVD players. Results can and will vary from one STB to the next.


2. The quality of the HDTV display device - Regardless of a particular DTV's ability to accept and display either 720p or 1080i program sources, there are numerous variables inside a particular set that will, to some degree, limit the ultimate perceived high frequency video detail. The majority of consumer DTVs cannot *fully* resolve all of the picture detail that *may* appear at their inputs (see 1. above). When I say fully, I mean 100%.


We use a Princeton AF3.0HD hi-def monitor in our NJ demo room. This model is fully capable of accepting very high quality HDTV signals, as it features a Joe Kane-designed video front end, with a reported 80 MHz bandwidth, and meets his demanding specifications, and has none of the usual picture-meddling "tricks" that are found in most consumer DTVs. But, you can't see all that detail, because the picture tube itself can't show it. It cannot fully resolve a 720p and/or 1080i picture, it simply doesn't have enough pixels. Some detail is lost because of the limitations of the display device (the picture tube) itself. Joe Kane showed this to me at his facility recently, using some very expensive HDTV test generating equipment. Nonetheless, it's still a fabulous-looking set, producing very pretty HDTV pictures.


In the case of the Denon AVR models that feature component video switching via ICs, there may be a *slight*, and I say again *slight*, possibility that when viewing a DTV set top box outputting 1080i or 720p real (not upconverted) hi-def material, there *might* be a slight softening of the extreme picture detail. Or maybe not. Depends entirely on 1. and 2. above.


But, the 720p or 1080i signals *will* pass through the Denon's component video switching stage.


You can test this for yourself - easily. Plug your DTV STB directly to your DTV set. If you're lucky enough to have either DirectTV HD or DISH HDTV, go to the HDTV demo channel, and use that as your source. Avoid looking at the film-originated content (some of that is upconverted), instead look at the sourced-from-high-def video content. Retailers can try this with their in-store Sencore HDTV demo generator if they don't have satellite hi-def coming into their store.


Compare the visible performance when the STB is driving the DTV directly, and again when the signal is "passed" through the AVR. Don't look for any minute color or brightness differences (which *might* occur if there are *slight* level differences between direct-to-the-DTV and passed-through-the-AVR signals), instead look specifically for the very finest picture details to see if there are any differences.


Dealers who have a suitable HDTV generator box (like the Sencore, which more and more dealers are acquiring, it's a great deal at $2,000) can test this via the multi-burst 720p or 1080i patterns. Run the multi-burst pattern through the AVR and then direct to the DTV, and compare. Look only at the far right multi-burst portion (that's the highest frequency burst, and the one most likely to be affected by the AVRs upper frequency response limitations). If the DTV display has a native 720p display rate, use the 720p multi-burst. If the DTV display has a native 1080i display rate, use the 1080i multi-burst. If the DTV display has a lower native display (540p), use another DTV for the test. All of the above assumes a high quality, calibrated/focussed set, with as much of the picture-meddling functions disabled as possible, especially Scan Velocity Modulation (SVM) which dynamically messes up fine picture detail.


DVD 480p with AVIA and/or Video Essentials isn't going to be a sufficiently high frequency signal source for this type of test, as 480p requires only about 10-12 MHz of switching bandwidth to pass cleanly.


All Denon AVR receivers with component video switching will pass 480p, 720p and 1080i. The top model AVR-5800 has the most transparent video pass-through as it has the higher bandwidth capability, and should be your first choice if you have a very high resolution DTV display.


Since last fall, when Gary's report first came out, I have followed all of the A/V publications, and have looked at various A/V online journals, and I've not yet seen any reviewer/publication address the concerns he's raised by subjective and objective testing.


So, until a suitably competent and suitably equipped and suitably motivated 3rd party undertakes a proper and thorough examination of this topic, the questions that Gary has raised may still remain unanswered for some folks.


------------------

Wayne Harrelson

Germantown, MD
http://www.geocities.com/wayneharrel...HTPC_Page.html

http://www.mp3.com/karnis


[This message has been edited by Karnis (edited 07-15-2001).]
 

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Discussion Starter · #3 ·
Wayne,


I previously missed the connection between this paragraph and the RX-V1
Quote:
I watched as Gary tested the other model, the one which also had relay switching, but had been quoted by the manufacturer at 20 MHz, -3 dB. I couldn't see any reason why this should be so low, so out of purely professional curiosity, I stayed around while Gary did the same test. Of course, it wasn't such a bad performer after all, it provided (as I expected it would) very similar (and quite acceptable) frequency response compared to the AVR-5800, again, within the limitations of the test equipment at hand.
Since the RX-V1 presumably has relay switching, it probably does have adaquate bandwidth. Thanks.


Jay
 

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Jay, I agree the Yamaha is the one they are "discussing".

I read in a thread ( http://pub7.ezboard.com/faussiedvdan...tart=1&stop=20 ) in another forum that the Yamaha does have "passive" relay switching, and has sufficient bandwidth for HDTV signals. I'm tired of endless "rigging" of my 3 component based video sources and ready to upgrade. I've been a Yamaha guy for awhile, 6.1 sound is not a priority at this time and the price is a little better than the Onkyo or Denon. My Pronto is using DSP-A1 IR codes so the RX-V1 makes for an easy upgrade.


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Wayne Harrelson

Germantown, MD
http://www.geocities.com/wayneharrel...HTPC_Page.html

http://www.mp3.com/karnis




[This message has been edited by Karnis (edited 07-15-2001).]
 

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As should be the case (not the raking part). The fantasy of relay switching providing "unlimited" head room is hooey.


Wayne,


Let yours eyes decide, just don't expect the same bandwidth as the Denon or the Onkyo. If you want Yamaha it is probably "good enough" for your application, but don't expect the same all around.


Tim

 

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Ok, I answered my own question with some more research:
http://www.yamaha.com/cgi-win/webcgi...gAVR00010RX-V1


"COMPONENT VIDEO INPUTS:

The RX-V1 also incorporates 3 sets of component video inputs. They are for DVD, D-TV, & CBL/SAT and are also fully assignable to another video input source. Bandwidth is DC-100 MHz - 3dB and is fully capable of passing HDTV signals."



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Wayne Harrelson

Germantown, MD
http://www.geocities.com/wayneharrel...HTPC_Page.html

http://www.mp3.com/karnis


[This message has been edited by Karnis (edited 07-15-2001).]
 

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Discussion Starter · #9 ·
Quote:
Originally posted by Michael Mullis:
Just a second, I mentioned this in the audio forum, and you raked me through the coals on it. That's not right. http://www.avsforum.com/ubb/smile.gif
Sorry about the "raking" http://www.avsforum.com/ubb/smile.gif . It would be interesting to know whether the RX-V800 has the "relay" based switching (that the RX-V1 probably has) or the cheaper video switching IC method. On the Denon line only their flagship 5800 has the better relay method and all the other models have the cheaper method.


***edit***


I just looked on Yamaha's web site and for the RV-V800 the spec is "Component Signal...DC-30MHz, -3dB". This probably indicates that it is using the cheaper video switching IC method like the similar Denon models. Although not as good as the high end receivers it is still probably "good enough" for most HDTV displays. I guess the only way to know for sure is to test it on your own system with quality cables.


Jay


[This message has been edited by jerndl (edited 07-16-2001).]
 

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Quote:
Sorry about the "raking"
It's ok. I was being lighthearted about it. I knew what you were getting at with all that.

Quote:
I just looked on Yamaha's web site and for the RV-V800 the spec is "Component Signal...DC-30MHz, -3dB". This probably indicates that it is using the cheaper video switching IC method like the similar Denon models. Although not as good as the high end receivers it is still probably "good enough" for most HDTV displays. I guess the only way to know for sure is to test it on your own system with quality cables.
I'm guessing that as well. My real test will be coming this week. I am moving my equipment to the adjoining wall of my TV, and I had to order a 25ft component run. Once I get that in place I will give the system a good run-through. I'll post my findings. So far, with a small 6 ft run, things seem to be pretty good. No visible signal loss so far. Keep your fingers crossed for me. http://www.avsforum.com/ubb/smile.gif


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Michael Mullis

Director of US Operations

Next Level Gaming
http://www.nlgaming.com
 
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