WQXR AUDIO CHAIN

[fm-engineer]

IMHO, Harris Digit AES module= One of the worst designs ever by Harris. The early plastic boxes had RFI problems. All versions have overshoot problems caused by the 32 kHz sample rate.

Overshoot did not occur at any sample rate from 32 kHz to 56 kHz if/when the incoming AES-3 audio from the station's audio processor was properly bandwidth-limited (~16 kHz). There were (are?) hundreds of DIGIT/Orban 8200 combos with punchy, overshoot-free modulation performance using the DSP stereo generator in the DIGIT.

Standard digital sample rates greater than 32 kHz and the spectrum above 16 kHz that they can convey aren't of much use in generating an FCC-compliant, FM stereo waveform -- which doesn't permit program modulation in the region of the 19 kHz pilot. Passing spectrum above 16 kHz also complicate the performance of audio processors because of the higher value of analog FM pre-emphasis in that region of the audio spectrum.

Besides which, few adults or even teens these days can hear much above 16 kHz, even in a well-controlled listening environment.
//

So Mr. Fry,

Was the Digit designed only to be used with the 8200? Many people found out rather quickly that 8100's and other analog boxes had problems as well. Somewhere I have a test that proved an 8100 into a THE-1 is about a .75 dB louder than into a Digit. Frank describes similar results above. BTW, the 8200 wasn't a very popular processor. Many stations went back to the 8100 and later onto the Omnia.FM.

 

[Sgeirk]

I don't know if I agree with the 8200 being an unpopular processor. Now? Sure.

About 1998, they were flying high, everywhere stations were buying them. I still hate them. Yes, hate.

 

[rfry]

The overshoots occurred because the signal content that existed in the 15kHz -> 18kHz domain, would overshoot in the 16kHz LPF in the DIGIT. I proved this in our lab. BTW: I used an 8100 for the test, and it had overshoots!

Frank: Do you deny that if you, or anyone else then or now using the AES-3 output of an Orban 8200 connected to the AES-3 input of the DSP stereo generator module of the Harris DIGIT exciter produced / can still produce no significant peak modulation overshoot of the DIGIT?

RF

 

[FFoti1]

Frank: Do you deny that if you, or anyone else then or now using the AES-3 output of an Orban 8200 connected to the AES-3 input of the DSP stereo generator module of the Harris DIGIT exciter produced / can still produce no significant peak modulation overshoot of the DIGIT?

RF

What's the point? I don't care about the 8200, there's hardly many of them out there anymore.

The DIGIT failed, as it seemed to work with only one product. Whereas, it should have supported ALL audio processors, both analog and digital that were connected to the AES input. Talk about short-sighted design...this was it!

-Frank Foti

 

[rfry]

What's the point? I don't care about the 8200, there's hardly many of them out there anymore.
-Frank Foti

Your backpedaling is noted, not that it changes the realities here.

The DIGIT failed, ...

Hmm. Below how many thousands of delivered and on-air DIGITs
around the world does your assessment apply, and what is your
proof of same?

RF

 

[FFoti1]

Your backpedaling is noted, not that it changes the realities here.

Actually, the backpedaling is on your end, by not acknowledging that FM audio spectra exceeded 16kHz long before the DIGIT became a warped thought in Harris' mind. The reality is the DIGIT failed technically...AND...your failure to acknowledge its fatal-flaw: It did not support ALL audio processors with regards to overshoot. Further proof are all the additional slam postings, by others, against the DIGIT.

Hmm. Below how many thousands of delivered and on-air DIGITs
around the world does your assessment apply, and what is your
proof of same?

RF

We're speaking technically here, not sales. Proof is in the technical performance of the product, or lack of performance in this case. All of this has been proven and documented, yet you continue to try and defend something that has been universally lambasted, by the engineering community, for over 10 years. Richard...might be time to give it up on this one.

Peyton Manning, in one of those "Priceless" commercials would probably suggest you try something like fly-fishing.

-Frank Foti

 

[menotti1]

Harris had salesmen that could blow some serious smoke.Must have learned it from engineering..The digit became the DITCH IT.i switched to the BE FX 50 with Omnia processing.Now that's what you call smoking.Now using Nautel for xmtr.Great product..

 

[rfry]

[We're speaking technically here, not sales. Proof is in the technical performance of the product, or lack of performance

So, Frank, if the DIGIT was / is unable to perform as excellently as it does with a digitally compatible modulation processor, to what do you attribute its commercial success?

RF

 

[FFoti1]

So, Frank, if the DIGIT was / is unable to perform as excellently as it does with a digitally compatible modulation processor, to what do you attribute its commercial success?

RF

Success? You over-inflate the DIGIT.

Most of those were purchased, due to Harris propaganda sales push. They have LONG since been replaced by other models, or brands, because the DIGIT did not perform to the demands of today's broadcasters.

-Frank Foti

 

[rfry]

Most of those were purchased, due to Harris propaganda sales push.

Sorry, Frank, but your "propaganda" proclamation doesn't support such sales figures, no matter how much you hope(d) that to be true.

People these days are not as dumb as you believe.

RF

 

[FFoti1]

Sorry, Frank, but your "propaganda" proclamation doesn't support such sales figures, no matter how much you hope(d) that to be true.

People these days are not as dumb as you believe.

RF

No, people are not dumb, hence the reason they moved away from the DIGIT.

You're groping at straws now. My info is based upon data our support staff have collected, along with comprehensive information and feedback supplied by dealers and other exciter/transmitter companies. The product did sell primarily during the time, and temporarily, was the first digital exciter. But, as history has proven, it ended up being a failure due to its lack of performance.

If it was so successful, then the numbers you claim would still be on-the-air, but most of those have been replaced, or switched into backup service. A successful product remains in the 'main chain' for a very long time.

You've been away from the real business world a tad too long.

Odd, I don't see you respond to the other critical postings of the DIGIT. Those are actual customers, and you should be trying to win them over.

-Frank Foti

 

[CalifZeke]

Frank: Do you deny that if you, or anyone else then or now using the AES-3 output of an Orban 8200 connected to the AES-3 input of the DSP stereo generator module of the Harris DIGIT exciter produced / can still produce no significant peak modulation overshoot of the DIGIT?

RF

Ah, I had a client, who had the digit and an 8400. It had overshoots about 15% above 100% modulation. After looking into the reason why, it was because the 8400 filter was not as tight as the harris guys wanted it.

The fix was to toss the digital input, and use the analog mpx card. Overshoots went away.

 

[menotti1]

Most engineers that i have known thru many years will agree that continental and BE make the best exciters and TONS of them are still in service.Califzeke, i had that same problem at various installations.Harris does not have the balls to admit they were wrong.that irks me more than anything.had a mw1 that had variac transformer problems the FIRST week it was installed.All i got was good lip service and alot of doubletalk.

 

[Sgeirk]

Took a digit offline in Kansas City. Replaced with an 802A. Cleaned up a lot of multipath areas and the analog input sounded far better than the aes.

 

[OKCRadioGuy]

Harris to me is like Ford. Year after year they keep building the same ()*#$ up design that they know is wrong and just keep putting out the brainwashing sales pitch to try to overcome it. They know the Digit has had this problem for years and have chosen to do nothing positive about fixing the problem. On another related note I have a Harris CD Link STL that has a stereo generator built into the receiver end. The damn thing, slightly out of warrantee decided to stop working on the reciever's stereo generator. (I was feeding AES/EBU right into the STL transmitter from the Optimod so it had to generate the stereo at the STL reciever end in this configuration) After the generator failed I decided to just move the Optimod to the transmitter site thereby eliminating Harris' stereo generator. OH MY! All of a sudden the station sounded WONDERFUL whereas it used to be muddy and sound less pleasing. There's a reason Bob Orban orignally put the stereo generator and the processor/filters into the same box. Frank and Bob are a HELL of a lot better at stereo generation AND making sure things work together properly in filters to make them where they won't cause ringing that causes overshoot, etc. IMHO.

 

[chrish]

I have the same situation as Freebird, two Harris ZCD series transmitters with Digits.both had Digital interfaces with two Omnia 6's . Audio was hideous, started by feeding composite to the emergency (SCA) input. The grundge cleaned up a bit but the fidelity was SCA quality with a severely rolled off low end.
Harris sent me an analog interface which I have had to use with the Omnia composite output and the results are outstanding but am still unable to use AES.
I recently dumped the whole mess onto Harris's field services lap and am holding up
a Harris-PR&E 4 studio Digital turnkey installation until I get satisfaction.
I advised them that the problem they have continue to duck with hope it will fade away is about to blow up in their face and they would be smart to start reading
the engineering blogs on the subject.
If anyone is interested in putting pressure on them send me a private email if other engineers come foward they will have no choice but to come clean, admit there is a problem and resolve it.
If they won't I have always had good luck with Wheatstone audio

 

[CalifZeke]

Interesting...

Where's R. Fry now that plenty have slammed the digit. Typical harris guy...

 

[menotti1]

I think he took Frank's advice and took up fly fishing.Forget to mention the Yard Console with the rectifier problem in the power supply.seems it was too hot for the socket( or a dam cheap socket) they used or a bad motherboard design.It would short, guess what NO AUDIO could pass.Literally had to do a news cast with a rag in my hand holding it against the socket.replaced the socket,mounted it higher off the pcb.problem solved, NO thanks to Harris....

 

[rfry]

[

Interesting...Where's R. Fry now that plenty have slammed the digit. Typical harris guy...

The point was made and not denied that audio processor AES-3 spectral content above ~16 kHz is responsible for the modulation overshoots when using such processors, and is not present when using AES-3 processors / sources that are clean above ~16 kHz.

This is different than the blanket beliefs being posted in this thread that the DIGIT always overshoots when using its DSP stereo generator.

What would be the purpose of repeating the posts that dealt with this reality?
//

 

[PHRaCaS]

Hmm. Below how many thousands of delivered and on-air DIGITs
around the world does your assessment apply, and what is your
proof of same?

RF

It would be interesting to know how many Digital Input Modules were returned to Harris for Analog Modules.