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Coupon Eligible Converter Box (CECB) > Zenith (LG) DTT900 CECB
holl_ands's Avatar holl_ands 02:15 PM 04-30-2008
There are hundreds (thousands?) of ANSI, IEEE and CEA standards for
design and test of various equipments. Here's a recent status update
containing a small sample of those currently under revision by CEA:
http://www.ce.org/PDF/2008-03-31CEAS...thlyUpdate.pdf

Nitewatchman's Avatar Nitewatchman 06:00 PM 04-30-2008
Quote:
Originally Posted by holl_ands View Post

There are hundreds (thousands?) of ANSI, IEEE and CEA standards for
design and test of various equipments.

Yes there are .... and I'm sure anyone interested who doesn't already know that are thankful to you for pointing that out .....

Note: I should clarify, In my last post, when I said :

Quote:
Originally Posted by me View Post

There are no receiver performance standards I'm aware of which, specify any specific technical requirements for standards involving the quality of the analog audio output of DTV receivers.

I was referring to no *Required* receiver performance standards regarding specific technical requirements related to quality of analog audio output of DTV receivers, such as not "required" by FCC, or "not required" by NTIA for CECB's ...

Thus I have corrected my post by inserting the word *required* before "receiver performance standards" ....

In any case, What audio based standards regarding quality of audio output does Zenith/LG claim the DTT900 meets ?
rrrrrroger's Avatar rrrrrroger 07:03 AM 05-01-2008
The DTV audio codec might have 20-20,000 Hz range, however if the DTV audio is encoded at a very low bitrate (to squeeze even more channels into each station), then the upper range will drop. As example, MP3 encoded at 64 kbit/s has a topend of only 10,000 hertz. AAC+SBR is slightly better, but it too only goes to 15,000 hertz at 64kbit/s, not the full human range of hearing.

If NBC, CW, whoever is trying to squeeze 5.1 surround sound into only 128 or 192 kbit/s, there will be a decreased frequency range.

When the bitstream lacks sufficient space, it's the high frequencies that get sacrificed by the Encoding software.
Quote:
Originally Posted by Falcon_77 View Post

However, I don't see a huge benefit in getting mutliple CBS, NBC, etc. stations. ...

The benefit happens in the afternoons and weekends, when each station does Local programming. For example, my NBC11 is not showing the same thing as NBC10 or NBC8 on saturdays/sundays. Having more stations offers more variety (typically old movies or old shows) on afternoons & weekends.

Out-of-market reception also enables me to watch Independent stations. A lot of the best programming comes from these non-affiliated Philadelphia or Baltimore stations.

Bottom line, as stated in my signature, it's about variety. (Or in the case of DTV, "loss" of same.)
Quote:
Originally Posted by TalkingRat View Post

If it's just that you're counting channels and want more, then pay tv was the winner before this conversation began.

It helps if you read my signature. I will highlight the relevant portion (paraphrased from memory): I am:
- losing Baltimore and Philly sports,
- losing Telemundo
- losing a favorite PBS station that shows lots of classic TV and/or movies
- and losing 2 national networks called MyNetworkTV and ABC.


That stuff is available for free with Analog television, but disappears with digital, due to lousy design of the transmitting system.
Quote:
Originally Posted by hphase View Post

you've already shown you don't have any talent for doing so, nor is it necessarily valid.

Yeah you're right. I have no clue. I'm just an engineer with two (soon to be three) degrees. What could an EE possibly know about electronics? Absolutely nothing. /end sarcasm
hphase's Avatar hphase 07:42 AM 05-01-2008
Quote:
Originally Posted by rrrrrroger View Post

The DTV audio codec might have 20-20,000 Hz range, however if the DTV audio is encoded at a very low bitrate (to squeeze even more channels into each station), then the upper range will drop. As example, MP3 encoded at 64 kbit/s has a topend of only 10,000 hertz. AAC+SBR is slightly better, but it too only goes to 15,000 hertz at 64kbit/s, not the full human range of hearing.

If NBC, CW, whoever is trying to squeeze 5.1 surround sound into only 128 or 192 kbit/s, there will be a decreased frequency range.

When the bitstream lacks sufficient space, it's the high frequencies that get sacrificed by the Encoding software.

....Yeah you're right. I have no clue. I'm just an engineer with two (soon to be three) degrees. What could an EE possibly know about electronics? Absolutely nothing. /end sarcasm

Your statements continue to belie your education.

DTV in the USA does not use MP3 or AAC+SBR, even though in your world you would make it so. DTV does not try to send 5.1 channel surround in 128 or 192 kb/s. You are correct (for once) that lowering the bit rate can result in a lower high frequency cutoff. A little research on your part would reveal that DTV audio is Dolby Digital, and the upper limit for 5.1 at 384 kb/s is 15 kHz. 5.1 at 448 kb/s (similar to DVD) has an upper limit of 20 kHz.

In your parrot response to me you neglected to answer the question I posed in my post. Where in your referenced document do you find the "facts" you quoted?
mrvideo's Avatar mrvideo 08:44 AM 05-01-2008
Quote:
Originally Posted by Nitewatchman View Post

How do you know that, regarding the analog audio output from "any receiver" ?

For example, A DAC must occur for any DTV receiver with analog audio outputs. Who is to say the quality of the DAC will be the same from "any given make/model of DTV receiver?"

Since the audio spec for AC3 goes to 20 kHz (I suspect at the normal measurement value of -3db), having it roll off at 16 kHz would not be good.

So, yes, it was a broad statement.

Quote:


Compare "frequency response" from analog audio (line out) DTT900 to another receiver(In my case a Zenith HDV420 HD receiver - I also compared it to analog audio output from a "HTPC") using the same sources like I have done(with ears or even better, if you like Non-subjectively with test equipment, software based analyzer/etc.), see what you think.

All I have is the MyHD card and an older top-of-the-line (at the time) Samsung STB. I'll have to do some tests one of the days.
mrvideo's Avatar mrvideo 08:55 AM 05-01-2008
Quote:
Originally Posted by hphase View Post

A little research on your part would reveal that DTV audio is Dolby Digital, and the upper limit for 5.1 at 384 kb/s is 15 kHz. 5.1 at 448 kb/s (similar to DVD) has an upper limit of 20 kHz.

Damn, never knew that that 384 kbps only goes to 15 kHz. That sucks. Explains the roll-off I've been seeing.

Thanks for the info. Is there a link on the Dolby web site that lists the bandwidths of the various rates?
mrvideo's Avatar mrvideo 08:57 AM 05-01-2008
Quote:
Originally Posted by rrrrrroger View Post

and losing 2 national networks called MyNetworkTV and ABC.

Didn't I read somewhere that you still receive an ABC affiliate via DTV? That means you are not losing the ABC network.
rrrrrroger's Avatar rrrrrroger 09:37 AM 05-01-2008
Well I am *supposed* to receive the Harrisburg ABC station, but I can't get it to tune-in with my Zenith DTV box. (Even with analog it's difficult to receive, but at least there was a picture that I could watch; with digital there's nada.) The Harrisburg CBS station is difficult to receive too. Maybe it's time for me to move to a local hilltop. ;-)
Quote:
Originally Posted by Falcon_77 View Post

Hopefully, we will see some SFN's deployed in the US after the transition, as long as the WSD (White Space Device) coalition doesn't get the go ahead to work its way into the spectrum.

What's an SFN? ..... Never mind, I found it on wikipedia. I don't see how the addition of more transmitters is going to help things. Most stations are happy with their local coverage of their home cities.

Also according to wikipedia, SFNs would actually create more problems with multipath/ghosting, thus making DTV even more difficult to receive.

My hope is that the FCC wises-up, realizes how difficult DTV is to receive (from the millions of consumers complaining), and then doubles the broadcast power for most stations. Otherwise I'll probably end-up doing more internet downloading just so I can continue watching my favorite MNT or ABC shows.
Quote:
Originally Posted by hphase View Post

Quote:
Originally Posted by roger View Post

As example, MP3 encoded at 64 kbit/s has a topend of only 10,000 hertz.....

DTV in the USA does not use MP3 or AAC+SBR,

What part of "as example" did you not understand?
holl_ands's Avatar holl_ands 10:48 AM 05-01-2008
Quote:
Originally Posted by hphase View Post

A little research on your part would reveal that DTV audio is Dolby Digital, and the upper limit for 5.1 at 384 kb/s is 15 kHz. 5.1 at 448 kb/s (similar to DVD) has an upper limit of 20 kHz.

Although I'm reluctant to get in the middle, I still feel the need for accuracy.
DTV frequency response extends BEYOND 20 kHz.

1. NTIA CECB Requirements are in Technical Appendix A:
http://www.ntia.doc.gov/ntiahome/frn..._technical.htm
which (sorta) cites requirements contained in ATSC A_53E:
http://www.wsfamily.idv.tw/weng/atsc...tsc-system.pdf
which in turn (pg 37) cites requirements contained in ATSC A_52B:
http://www.atsc.org/standards/a_52b.pdf

ATSC A_53E, sec 5.2 (pg 39) stipulates one and only one sampling freq: 48 kHz.
Hence upper frequency limit is roughly half that....24 kHz.
The resultant Dolby Digital output data rates are in the following paragraph.

AC-3 frequency response can be seen in A_52B, Table 7.24 on pg 80, where the
highest coupling sub-band extends to 23.67 kHz for 48 kHz sampling rate.
[AC-3 only has so many bits to allocate and can save bits by sending only one
channel for selected "coupled sub-bands".]

Since Dolby Digital implementations are embedded into standard chipsets, a
box manuf. would have to go out of their way to reduce freq response below 20 kHz.
[And most of us can't even hear 20 kHz....]

===========================
PS: ATSC A_53 was updated last year:
http://www.atsc.org/standards/a_53-Part-1-6-2007.pdf
Audio, Part 5 begins on pg 118.
Sec 5.2 (on pg 122) still stipulates 48 kHz sample rate (only).

==========================
BTW: ATSC A_52B documents GENERIC AC-3 requirements, rather than
specific DTV constraints stipulated in A_53E. [No doubt came from Dolby Labs.]
Note that Table 5.6 on pg 36 allows 48, 44.1 and 33 kHz sampling rates.
The document also contains Enhanced AC-3 (Appdx E) with reduced (24, 22.05 & 16 kHz)
sampling freqs for use with proposed E-VSB mode (to be superceeded by ATSC-M/H)
and even a Karaoke mode not mentioned in either version of A_53.
hphase's Avatar hphase 11:17 AM 05-01-2008
Quote:
Originally Posted by mrvideo View Post

Damn, never knew that that 384 kbps only goes to 15 kHz. That sucks. Explains the roll-off I've been seeing.

Thanks for the info. Is there a link on the Dolby web site that lists the bandwidths of the various rates?

The 15 kHz limit is for 5.1 modes (six channels.) Seeing how analog TV rolls off at 15 kHz, that seemed OK. I wouldn't say it "sucks." You might have seen the rolloff, but you probably didn't hear it. If you want 20 kHz in 5.1, go to 448 kb/s.

The manuals for the Dolby pro encoders give you the response data. The encoder is a DP569.
Whidbey's Avatar Whidbey 12:37 PM 05-01-2008
Quote:
Originally Posted by rrrrrroger View Post

Bottom line, as stated in my signature, it's about variety. (Or in the case of DTV, "loss" of same.) It helps if you read my signature. I will highlight the relevant portion (paraphrased from memory): I am:
- losing Baltimore and Philly sports,
- losing Telemundo
- losing a favorite PBS station that shows lots of classic TV and/or movies
- and losing 2 national networks called MyNetworkTV and ABC.

rrrrrroger - You should add your antenna configuration to your signature. Might help others better understand your situation and how to respond.
Jokester's Avatar Jokester 01:41 PM 05-01-2008
Quote:
Originally Posted by TalkingRat View Post

Happy with my volume at the moment. Last night I was surprised that things seemed much better on Brian Williams, I wondered if the station did anything. I still got silibance, but no chirp. Today after reading some of the suggestions about CECB volume, I tried it. I have CECB at 100, then turned the tv volume down, center volume down, rear volume up a bit, and set receiver on dolby normal. It's a much deeper tone and no chirp, and no silibance tonight.

My 50+ year old ears are still trying to hear the issue everyone is talking about on my DTT900.

I wonder, what is the opposite of the settings that you've described above, so I can try setting up my CECB and TV that way to try to hear it? Would you say that TV volume UP, CECB down ( maybe 75 or so?), and ensure receiver isn't on Dolby?

Oh, and I just had a <30yo friend listen to the WMTV-HD-NBCNews-0424-174916.wav clip, and she said she could hear (what we're calling sibilance) but nothing she could describe as fingernails on chalkboard.


...and why hasn't anyone suggested that we just stop listening to Brian Williams?????? (yes, a joke!)
mrvideo's Avatar mrvideo 01:44 PM 05-01-2008
Quote:
Originally Posted by hphase View Post

The manuals for the Dolby pro encoders give you the response data. The encoder is a DP569.

Got a page number. I've glanced through the manual and didn't find the info. I've not parsed it with a finetoothed comb.
mrvideo's Avatar mrvideo 01:46 PM 05-01-2008
Quote:
Originally Posted by Jokester View Post

Oh, and I just had a <30yo friend listen to the WMTV-HD-NBCNews-0424-174916.wav clip, and she said she could hear (what we're calling silibance) but nothing she could describe as fingernails on chalkboard.

I wouldn't call it fingernails on a chalkboard either. But it is highly annoying.
Nitewatchman's Avatar Nitewatchman 06:52 PM 05-01-2008
Quote:
Originally Posted by holl_ands View Post

Since Dolby Digital implementations are embedded into standard chipsets, a
box manuf. would have to go out of their way to reduce freq response below 20 kHz.
[And most of us can't even hear 20 kHz....]

Specifically involving decoding the AC3 audio streams, Yes, I agree the frequency response from "any box" which results should be the same as what is encoded ....

However, For the analog audio output which actually results from "any given DTV receiver" "at the output jacks" , I'm not so sure that tells the whole story ....

Although, I too would have THOUGHT it WAS "the whole story" until (independant of the "siblence" issue, even though that issue in and of itself was also certianly not something I expected to occur, either) I compared analog audio output from DTT900 to other receivers ....

HENCE why I reported a bit regarding my (admittedly short+subjective "by ear" ) tests on it, "independant" of the "siblience" issue ....

Quote:
Originally Posted by mrvideo View Post

All I have is the MyHD card and an older top-of-the-line (at the time) Samsung STB. I'll have to do some tests one of the days.

If you do happen to get hold of a DTT900 (from a friend/etc), and it isn't too inconvienent to give it a try, I'd be interested to know iif you do(or don't) notice the same thing I did ...

I just thought I'd post what I "observed"(errr heard) "by ear" on this -- I'm afraid I'm not really motivated to spend the time/effort try any more "objective tests"/comparisions with audio captures/etc, as it would be inconvienient for me to do so for various reasons ---

I just thought I'd post here what I'd "heard" regarding audio quality from the DTT900( "seperate" from sibilence issue as that's already been covered here quite extensively I believe) vs. analog audio out from other DTV receivers, as I thought it might be of interest to some, or thought others who might have a DTT900 and other DTV (HD receivers/etc) handy might also want to try such comparision as well and see if they noticed same thing I did/etc .....

Quote:
Originally Posted by hphase View Post

If you want 20 kHz in 5.1, go to 448 kb/s.

I've noticed most broadcast stations I receive send 384 Kb/s for either their DD 5.1 or DD 2.0 streams (48khz sampling rate).... Verified via tools such as TSreader, and software based A/52 AC3 encoding/transcoding tools/etc - since it's CBR, I suppose I could do a little math on the elementary audio streams after demuxing the TS as well, know what I'd get, though .....

I think in my area, The one exception are Fox affilates (via the "splicer") ... It's 448Kb/s @ 48khz for their DD 5.1 ...
holl_ands's Avatar holl_ands 07:00 PM 05-01-2008
Here's Dolby DP569 DD5.1 Encoder User Manual:
http://www.dolby.com/assets/pdf/tech...569_Manual.pdf

On page A-17/18 there is a Low Pass Filter that can be enabled (default)
to suppress frequencies ABOVE 20 kHz for anti-alias purposes.

I could find no other mention of frequency response in the User Manual.
DP569 spec sheet simply says it varies with data rate, sample rate & channel mode:
http://dolby.us/professional/pro_aud.../dp569_03.html

Here's Dolby DP564 DD5.1 DECODER Spec Sheet & User Manual:
http://dolby.us/professional/pro_aud.../dp564_03.html
http://dolby.us/assets/pdf/tech_libr...UserManual.pdf
Appendix lists freq response to 20 kHz (max output sampling is 48 kHz).

Dolby Labs repeatedly states that multichannel Dolby Digital is "full range",
citing 20Hz-20kHz frequency response, for example in fol:
http://www.dolby.com/assets/pdf/tech...6_DDfuture.pdf
http://www.bigscreen.com/about/help.php?id=44

Laser Disc uses 384 kbps DD5.1 (vice 448 kbps max for DTV & DVD).
Here is a Laser Disc for testing freq. response....out to 20.3 kHz,
so it is still "full-range" at the lower channel data rates:
http://www.laaudiofile.com/testtone.html

PS: There are many Lab Test Results for AV Receivers using DD5.1
DVD test signals....yup, they're 20Hz-20kHz freq. response.....
Nitewatchman's Avatar Nitewatchman 10:16 PM 05-01-2008
Quote:
Originally Posted by holl_ands View Post

1. NTIA CECB Requirements are in Technical Appendix A:
http://www.ntia.doc.gov/ntiahome/frn..._technical.htm
which (sorta) cites requirements contained in ATSC A_53E

sorry, missed commenting on this in my last post, I currently have some extra time, so here goes :

A53/E is certianly referenced in that Document as a "reference documents" and, in Techncial appendix 1 as follows and as specifically involves "Video formats" (from the famous or infamous Table 3) :

Quote:
Originally Posted by CECB requirements View Post

1. Decoder

Equipment shall be capable of receiving and presenting for display program material that has been encoded in any and all of the video formats contained in Table A3 of ATSC A/53E. The image presented for display need not preserve the original spatial resolution or frame rate of the transmitted video format.

But, follows below is all I can find in that document which specifies audio requirements for the CECB's -- especially note the "may" which I bolded from appendix 2 (Note ATSC A/54 Document is ATSC's "guide to Digital Television standard" which I believe I provided a link to in earlier post in this thread - Section 6.6 specifically involves "6.6 Main, Associated, and Multi-Lingual Services : For example, describes specifics regarding different audio streams for spanish language/hard-of-hearing/etc .....

Quote:
Originally Posted by cecb requirements View Post


From Tech appendix 1 :

19. Audio Outputs

The RF output must be modulated with associated audio program information; the RCA audio connectors must provide stereo left/right, when broadcast.

From tech appendix 2 :

Outputs (audio) :

Equipment may process associated audio services described in Section 6.6 of A/54

RF output may provide monaural audio for the selected audio channel.

RF output may provide BTSC stereo for the selected audio channels.

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

And now for something somewhat completely different .....

From the Group W Test bench files and a post I was going to make(on another thread, I think, as is the quote from Holl_ands) some time ago, but didn't .... If all these links still work, It seems one of the 27 glossy 8x10 photos, the one that shows the curly headed guy dumping the garbage may have went missing .....

Quote:
Originally Posted by holl_ands View Post

So far, I haven't bought any....because I have yet to see what I want:
Defect Free, Smart Antenna, S-Video, EZ-ADD, Signal LEVEL (not just Quality).

I am a bit puzzled by the NTIA requirements regarding the signal meters ...

Here :

TECHNICAL APPENDIX 1, NTIA Coupon-Eligible Converter Box (CECB),Required Minimum Performance Specifications and Features

It simply says on this issue :

Quote:
Originally Posted by doc at above link View Post

24. Signal Quality Indicator

The equipment will display on the television receiver signal quality indications such as signal strength per ATSC A/74, Section 4.7.

"such as" signal strength -- Not "has to be" signal strength meter ... Ok, well, I should just leave it at that, but the W bench group has inquiring minds so ....

We notice that in Federal Register/Vol 72, No 50/Thursday March 15, 2007/rules and regulations, page 12109 Paragraph 94 , a portion of the following document which begins onon page 12097 of Federal Register/Vol 72, No 50/ from Thursday March 15,2007 , entitled (note the "final rule" provision) :

DEPARTMENT OF COMMERCE
National Telecommunications and Information Administration
47 CFR Part 301
[Docket Number: 0612242667—7051—01]
RIN 0660–AA16
Rules to Implement and Administer a Coupon Program for Digital-to-Analog Converter Boxes
AGENCY: National Telecommunications and Information Administration, Commerce.
ACTION: Final rule.

it says :

Quote:
Originally Posted by Ntia DTVcouponFinalRules View Post

"NTIA notes that the A/74 guidelines states that ‘‘[t]he capability to display received signal quality conditions on a quasi-real time basis is a feature that should be included in all digital broadcast receivers.’’ To further assist consumers in improving signal reception, we include in the Final Rule provisions that require manufacturers to include software which will display on the television receiver signal strength and permit the display of other operating parameters chosen by the manufacturer. Display of signal information on the television receiver will provide information to the consumer at minimal cost. NTIA will not, however, specify exactly what such signal-quality information should contain. NTIA will follow the guideline of A/74, that
‘‘[m]eans to achieve such signal quality indications should be left to the judgment of individual receiver manufacturers.’’153

153 - 153 Advanced Television Standard Committee, Standard A/74, section 4.7 ‘‘Consumer Interface– Received Signal Quality Indicator.’’

Of course, ATSC doc. A74 "ATSC Recommended Practice: Receiver Performance Guidelines (with Corrigendum No. 1 and Amendment No. 1)" Section 4.7 says :

Quote:
Originally Posted by ATSC A74Doc View Post

4.7 Consumer Interface—Received Signal Quality Indicator
The capability to display received signal quality conditions on a quasi-real time basis is a feature that should be included in all digital broadcast receivers.
Unlike analog reception, transmission impairments such as echo, interference and noise do not manifest themselves in uniquely identifiable ways in a digital broadcast receiver’s display. Reception and display of digital signals on a digital receiver is largely a “go-no go” experience for the consumer, and the received picture or audio by themselves offer little useful guidance as to the relative difficulty of the current reception conditions.
A digital broadcast receiver’s digital signal quality indicator should be more than simply a signal strength meter, and should take into account the effects of multipath and interference impairments, as well as insufficient or excessive signal level. Moreover, the signal indicator should be easy to understand, intuitive to use and easy to access for a consumer in order to effectively position or aim an antenna, judge the need or effectiveness of additional front end amplification and/or aid in other user-controlled adjustments to optimize the receiver’s configuration with respect to the current reception conditions.
Receiver manufacturers should consider two applications of indicator displays; setup displays and operational displays. Each application should provide some manner of signal level indication as well as indications of the effects of multipath and interference impairments. Setup displays should be persistent to facilitate the installer’s achieving proper system alignment. Operational displays may be transient or under user control if desired. User options should be provided in both categories.
Means to achieve such signal quality indications should be left to the judgment of individual receiver manufacturers.

Hmmm ... A74 says a "signal strength" meter is not enough, and goes on to specify/recommend all the stuff we'd love to have (like the missing Glossy 8x10 Photo) as signal diagnostic tools on our receivers, but then says "Means to acheive such signal quality indications shuld be left to the judgment of individula receiver manufactuers" .....

Well, OK, for the most part that's what the NTIA info at first link above says as well ... but what about the part from vol 72 of federal register that says :

"We include in the Final Rule provisions that require manufacturers to include software which will display on the television receiver signal strength and permit the display of other operating parameters chosen by the manufacturer. " ...

Gee, that seems to the group W bench like it's saying they are specifically requiring signal strength meters ... did they revise/change/amend that or something, or did the rule get "shortened" and summarized by the time the manufactuers got the "spec sheet" so that it lost the "signal strength" meaning ?

If not then where's the signal strength meter on my Zenith DTT900's ????? I can't seem to find it, it doesn't seem to be the thing that pops up when you push the "signal" button, that looks to be a signal quality meter. And my guess is, it may be implemented along the lines (if not exactly like this) as discussed in a Document Hollands provided a link to earlier in thread, entitled : " Preliminary DTV Field Test Results And Their Effects on VSB Receiver Design" Gary Sgrignoli Zenith Electronics Corporation - 8/20/99 --

As follows (the last part being of most interest) :

Quote:
Originally Posted by Sgrignoli/zenith paper - portion of pg 3 paragraph 1 View Post


..... The MPEG data sync is reinserted at the receiver output for subsequent processing in the receiver’s MPEG transport decoder. The one-segment long binary frame sync not only provides pseudo-random number sequences (PN) for data frame synchronization, but can also be used as a training signal for the receiver’s equalizer and as a means to measure received signal quality.


You can get anything you want, except good signal diagnostic tools ...

I think The moral to this story may be either :

#1). Specs may be specs, but don't assume anything when you have "specs" that say things like : "signal quality indications which should be left to the individual receiver manufactuers" ....

#2). Welcome to the world of almost no required receiver performance standards ... exception involving a few requirements for the CECB's from NTIA, most of them "reception" related .... It's a situation where, as just one example we have broadcasters required to send 12 hours of EPG info via PSIP EIT's, but very few receivers which support displaying the info beyond the current or next program, if they even display that ....
pifermark's Avatar pifermark 09:19 AM 05-02-2008
Hello Everyone,
New to DTV. Need some help with hook up. I just got a Zenith DT900 and it works great! 28 channels in Tamp Bay. But I need to know if its possible to hook it up to my stereo and DVD player. I have a Phillips mant510 and a Zenith TV with L, R, V, and coax connection. Would like to get sound from broadcast through my stereo system and not have to unplug connections from TV to DVD player all the time. Any help would be appreciated!

Thanks!
CasualOTAer's Avatar CasualOTAer 11:00 AM 05-02-2008
Quote:
Originally Posted by pifermark View Post

Hello Everyone,
New to DTV. Need some help with hook up. I just got a Zenith DT900 and it works great! 28 channels in Tamp Bay. But I need to know if its possible to hook it up to my stereo and DVD player. I have a Phillips mant510 and a Zenith TV with L, R, V, and coax connection. Would like to get sound from broadcast through my stereo system and not have to unplug connections from TV to DVD player all the time. Any help would be appreciated!

Thanks!

Since it is basically line-level audio out, how about a couple of Radio Shack
274-303s or equivalent? Other than Y-adaptors or the like, there are also
audio selector boxes to handle multiple audio inputs to a single stereo, if you need that.
pifermark's Avatar pifermark 11:39 AM 05-02-2008
Thanks! Would I stick the Y-adaptors in the TV or converter? And would I use a 3rd Y-adaptor for the DVD player? Video(TV or converter) to Video(DVD)?
MikeBiker's Avatar MikeBiker 12:20 PM 05-02-2008
The manufacturer of the Zenith boxes seems to know about the audio problem and has a fix.

This is from http://www.hdtvexpert.com/pages_c/InBox26.html

Quote:


I spoke to Zenith/LG representatives at NAB 2008 and the culprit is an EQ setting in the audio processor. This has been upgraded recently (as has the processing chip). Apparently the problem occurs with a down mix of a Dolby Digital 5.1 surround audio track to stereo, and is not as common when watching programs with native stereo soundtracks. You may want to contact LG’s customer support line at 1-800-793-8896 and see if there is a warranty fix for this problem, or an exchange for upgraded boxes.


wh5916's Avatar wh5916 01:27 PM 05-02-2008
Quote:
Originally Posted by MikeBiker View Post

The manufacturer of the Zenith boxes seems to know about the audio problem and has a fix.

This is from http://www.hdtvexpert.com/pages_c/InBox26.html

Thank you for posting this. At least there's some hope now that the newer version of the converter won't have the audio problem. The phone number that was posted, though, is for LG mobile phones.
seatacboy's Avatar seatacboy 03:48 PM 05-02-2008
Quote:
Originally Posted by rrrrrroger View Post

My hope is that the FCC wises-up, realizes how difficult DTV is to receive (from the millions of consumers complaining), and then doubles the broadcast power for most stations.

Agree. In addition, the FCC should encourage full-power stations to locate their DTV transmitter at the highest possible altitude above adjacent terrain.

However, there may be political and business reasons these steps won't be taken by the FCC.
tvropro's Avatar tvropro 04:21 PM 05-02-2008
Quote:
Originally Posted by wh5916 View Post

If anyone would like to hear what many of us are experiencing with the Zenith/Insignia converters, the link below contains a zipped folder featuring a brief audio clip (under 8 seconds), taken from "NBC Nightly News" earlier this evening. The download is under 500k:

http://www.mediafire.com/?yuvynylztuv

The zipped folder actually contains two very high bitrate mp3 clips--the Zenith DTT900 was the source, with its audio output set for stereo.

One clip is left channel only, and the other is right channel only. The high-pitched "chirping" that many are experiencing is plainly audible in the left channel clip--but it should be noted that the quality of your speakers, and even your hearing, might possibly make the sound difficult or impossible to discern.

Also in the folder is a jpeg, showing a side by side comparison of a brief portion of each clip, as loaded into a wavefile editor set for spectrum display. In particular, note a portion of both clips that begins roughly at the 1 second 250 ms mark. The "chirping" sound (as the announcer is saying the word "Fenton") is visible as a green sort of rectangle in the left channel. There is also a great deal of blue that's visible in the left channel spectrum, above the 11,000 hz portion of the display, that you won't see in the right channel. This, again, is a graphic representation of the audible "chirping" noise.


I was listening to the sound clip on the left channel and comparing it to the right channel. It sounds like there's a pre emphasis on the left channel. I'll bet the issue could be tamed by doing a bit of filtering to the left channel with the proper value capacitors. I may pick up the Zenith and experiment with it. Then I could sell the cure back to LG
tvropro's Avatar tvropro 07:54 PM 05-02-2008
Well I went out and got a Zenith with my second coupon and just as said here it had the audio defect in the left channel. So I tore it apart and tried some filtering and I like the outcome. I took away almost all of the s... chirping in 5.1 broadcasts and that was just with some quick work. So the problem can be solved on our end if were willing to mod these things. What the heck I moded my Magnavox so no biggie. Im going to test it for a while before putting the fix up here since I may want to revise it from what I just did.

It's a shame the Zenith has the audio issue out of the box, it does have some cool features over the Magnavox. Don't get me wrong the Magnavox worked well for me and will be going on my other tv tomorrow. I did not gain any channels with the Zenith over the Magnavox. I just wanted more toys like Zoom on a fly that the Magnavox didn't have.
wh5916's Avatar wh5916 07:46 AM 05-03-2008
Quote:
Originally Posted by tvropro View Post

Well I went out and got a Zenith with my second coupon and just as said here it had the audio defect in the left channel. So I tore it apart and tried some filtering and I like the outcome. I took away almost all of the s... chirping in 5.1 broadcasts and that was just with some quick work. So the problem can be solved on our end if were willing to mod these things. What the heck I moded my Magnavox so no biggie. Im going to test it for a while before putting the fix up here since I may want to revise it from what I just did.

It's a shame the Zenith has the audio issue out of the box, it does have some cool features over the Magnavox. Don't get me wrong the Magnavox worked well for me and will be going on my other tv tomorrow. I did not gain any channels with the Zenith over the Magnavox. I just wanted more toys like Zoom on a fly that the Magnavox didn't have.

Though I used to love building Heathkits way back when, I've never done much with equipment modding, outside of adding a variable resistor to a click-style RCA varactor tuner, which made it possible to tune in several cable midband channels.

The above doesn't surprise me, though, as the sound issue is in the upper frequencies...and if it's possible to attenuate them with a handful of components, that would virtually take care of the problem.

I ran the Zenith through a 10 band audio equalizer the other day, and heavily attenuating the highest frequency did kill most of the chirping sound.

Yesterday, a poster provided a link indicating that LG is aware of this and has modified the circuitry...will they ever tell Zenith customer service about this though? I finally phoned them a few days back and got absolutely nowhere.
tvropro's Avatar tvropro 08:08 AM 05-03-2008
Quote:
Originally Posted by wh5916 View Post

Though I used to love building Heathkits way back when, I've never done much with equipment modding, outside of adding a variable resistor to a click-style RCA varactor tuner, which made it possible to tune in several cable midband channels.

The above doesn't surprise me, though, as the sound issue is in the upper frequencies...and if it's possible to attenuate them with a handful of components, that would virtually take care of the problem.

I ran the Zenith through a 10 band audio equalizer the other day, and heavily attenuating the highest frequency did kill most of the chirping sound.

Yesterday, a poster provided a link indicating that LG is aware of this and has modified the circuitry...will they ever tell Zenith customer service about this though? I finally phoned them a few days back and got absolutely nowhere.

What it all boils down to and is so commonplace these days is that these companys release products before they should. Then Joe unsuspecting smuck gets stuck with it. They figure the majority of people are too stupid or won't waste there time pursuing the issue.

What LG should do is send each person a new unit with the fix in it at LG's expense (those smart enough to complain) and if they want there defective unit back supply a postage paid box to send it in. That's how companies would bend over backwards in the old days. Now they lie and cheat and do anything they can to not acknowledge there is an issue and stick it to there bread and butter.

I like what my first generation filter does but want to do some refinements on it to try to achieve better results. Im thinking of maybe doing a Twin T type filter or notch vs a simple rolloff that I have now. I enjoy messing around with circuits. I like seeing what different effects different value parts do. Having a good understanding of electronics helps too. Time to warm up the soldering iron
wh5916's Avatar wh5916 09:03 AM 05-03-2008
Quote:
Originally Posted by tvropro View Post

What it all boils down to and is so commonplace these days is that these companys release products before they should. Then Joe unsuspecting smuck gets stuck with it. They figure the majority of people are too stupid or won't waste there time pursuing the issue.

What LG should do is send each person a new unit with the fix in it at LG's expense (those smart enough to complain) and if they want there defective unit back supply a postage paid box to send it in. That's how companies would bend over backwards in the old days. Now they lie and cheat and do anything they can to not acknowledge there is an issue and stick it to there bread and butter.

I like what my first generation filter does but want to do some refinements on it to try to achieve better results. Im thinking of maybe doing a Twin T type filter or notch vs a simple rolloff that I have now. I enjoy messing around with circuits. I like seeing what different effects different value parts do. Having a good understanding of electronics helps too. Time to warm up the soldering iron

Every now and then, a glimmer of decent customer service shines through...if only Zenith/LG would take a page from it. A recent line of Antec computer power supplies were total lemons, judging from my own experience and the number of online complaints. The one in my Antec case began showing signs of failing last July. I emailed Antec, as the supply had a three year warranty. They quickly provided an RMA number. Only problem--I had to mail the supply back at my own expense.

It was worth the time, trouble, and even the postage though...one week later, at my doorstep, was a brand new, still in the retail box, Antec power supply--their newest model, totally different from the defective unit sent to them. It even was a bit more powerful, 380 watts versus 350. 8 months later, it's still working beautifully.

Best of luck with the mod. I'd still like to see LG do the right thing and correct this for current customers, at least the ones who've noticed it and aren't happy.
tvropro's Avatar tvropro 11:30 AM 05-03-2008
Quote:
Originally Posted by wh5916 View Post

Every now and then, a glimmer of decent customer service shines through...if only Zenith/LG would take a page from it. A recent line of Antec computer power supplies were total lemons, judging from my own experience and the number of online complaints. The one in my Antec case began showing signs of failing last July. I emailed Antec, as the supply had a three year warranty. They quickly provided an RMA number. Only problem--I had to mail the supply back at my own expense.

It was worth the time, trouble, and even the postage though...one week later, at my doorstep, was a brand new, still in the retail box, Antec power supply--their newest model, totally different from the defective unit sent to them. It even was a bit more powerful, 380 watts versus 350. 8 months later, it's still working beautifully.

Best of luck with the mod. I'd still like to see LG do the right thing and correct this for current customers, at least the ones who've noticed it and aren't happy.

We will have to wait with LG and see.

I just finished version 2 (rev B). I found a simple rolloff seems to work better. This time I dropped the rolloff freq a bit more. I tried to match the frequency response of the right channel as close as possible. Then I had to do a bit of attenuation to the right channel to match the levels. I ran wires to the PCB bottom now and made a little PCB to put my parts in. This way I don't have to keep pulling the unit all apart to change mod's. There was some DD cartoons on that I used for attenuating the anomaly. I want to test it with more DD content still. If this version works well it will be simple to add for anyone with a background in electonics and can solider, since it's based on only a few parts.
Avio's Avatar Avio 01:03 PM 05-03-2008
Anyone notice how most all the LG chip based CECBs (Zenith, Insignia, DS) are all a fixed price of $60, with no special offers or discounts available? Of course you have!

It almost seems as though LG and the big box stores, CC, BB, RS, (& now H.H. Gregg) have agreed to price fixing.

I used my 1st coupon to run out to CC and buy a Jan.08 built DTT900 for full price on March 3rd to be the first in-store purchaser. I waited until yesterday to use my second coupon, and I did my homework this time.

First, I went to dtv2009's VendorSearch and scrolled down to "Locate Retailers Near You." I keyed in my Zip Code and changed the "Search Distance" to 25 miles. I got 40 hits, most of which were the big box stores, but 3 vendors were smaller independent dealers. It turns out that 1 vendor was an electronics and appliance discounter and they sold the Zenith for $49.88.

When I went there they were sold out. They were getting new shipments in each several days. I asked the TV Dept. Manager to write a price quote for the Zenith DTT900 on the back of his business card. I then went to the nearby CC and asked to speak with the TV Dept. Manager. I explained that this local competitor was selling the Zeniths for about $10 less than CC. I told her that I understood CC's Price Matching Policy and that I knew it included a part that the local competitor had product In-Stock. I elaborated that the competitor's Zeniths were selling so fast that they were In-Stock one day and Out-of-Stock the next. I said I had a strong preference to buy my boxes from CC. She responded, "No problem, as long as the competitor's current price was lower."

Conclusion: I purchased 3 late March 08 built DTT900's for $48.99 each (about $1 lower than the competitor) plus tax. I used my 2nd personal coupon and my elderly Mother-in-law's two coupons. I then contacted several other elderly or disabled individuals in my area that I'm helping with DTV conversion and told them the procedure on how to have CC match the competitor's price (I gave them the name of the cooperating CC manager).

I realize that these Zenith boxes will probably have the audio issues being discussed in this thread, but I can live with that, particularly with the boxes in Mono mode and for the price I paid. I ended up paying $12.36 per box (including tax) out of pocket. Now I have the challenge of visiting my Mother-in-law, who lives in a somewhat rural, remote area, and setting up DTV for her. TVFool.com indicates that it may be a little difficult. Then, after DTV is setup, we cancel her Comca$t and save her $44/month.

Avio
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