"Hi-Deaf" introduces new audio processing problems

[radioskeptic]

Most of us on htis board have been concentrating either on interference problems or on the promised, but non-existent "robustness" of the "HD" signals, which in fact are extremely fragile.

But what about the problems the delay causes with audio processing?

Consider this exchange on the thread, "KRTY audio is THE WORST I've ever heard" from the San Francisco board (http://www.radio-info.com/smf/index.php/topic,66117.0.html), which appeared as Replies # 3 and 4 (from "Timmy" and "Uncle Fester" respectively):

I know one of my pet peeves is when talking up or down a song, the mic is so low that the music kills the jock. I hear that on Sirius a lot. Are jocks just not messing with the levels? Are PD's or Engineers telling them not to touch? I would think the music level would stay at the same level, but the Mic would need to be higher to "overcome" the music. Just my thoughts.

There is a simple reason for the level disparity you mention. In the "old" days (talking analog radio) jocks could listen off-air and they'd actually "mix" on the console so that they would sound good (level wise) compared to the music. In the case of Sirius, and indeed many terrestrial stations, you can't do that because the long delays (8 seconds in the case of HD -- and longer when you have a profanity delay built in) prevent you from hearing what the listening audience is actually hearing. So in many cases we "fake" a processor for headphones only that allows the jocks to hear some processing while they talk. Unfortunately this "fake" processor doesn't always react the same way the on-air one that you hear does. I don't know how Sirius addresses this issue, but from what you are saying, it could be nothing.

How on earth can you get a good mix on the air when you can't hear that's going out over the air IN REAL TIME!?! Do you have the processed signal sent back to the studio for that?

And what if there is completely different processing for analog and digital?

This whole Mickey Mouse/Rube Goldberg approach to "modernizing" radio is insane!

 

[wgliradio]

Two things here

Alot of digital processors have poor AGC designs. Even if jocks are listening off air, the boxes are a horror.

In my studio at home, I have a DSP-X, Optimod 6200, Inovonics Omgea, Optimod 8100 and an Ariane (enough to put on 5 stations, right?) I have worked with the Omnia 5EX-AM, Omnia 6 and Omnia 3 FM turbo and Omnia 3 AM in addition to the above.

The only boxes worth a damn with their AGC's are

Ariane with any of the above
Compellor/Prisms with the 8100
8100 by itself (the 8100 has a very natural sound barefoot)

None of the digital boxes have good front ends. Couple that with the fact that the jocks can't hear the TRUE on air mix and voila.

You would be amazed at how good the 8100 and the Ariane sound together. Everything is not smashed to hell, it is loud, it is consistant but not over the top. Very pleasing to listen to. It is the best sounding setup I have heard in a very long time. Everytime I listen to one of my other boxes, I always go back to that setup and it just sounds right. All elements always mix well. Also, the bass on the 8100 sounds better than the 6200, which adds too many tricks to get too much of a synthetic sounding bass. Keep it simple.

 

[R.F. Burns]

Two things here

Alot of digital processors have poor AGC designs. Even if jocks are listening off air, the boxes are a horror.

In my studio at home, I have a DSP-X, Optimod 6200, Inovonics Omgea, Optimod 8100 and an Ariane (enough to put on 5 stations, right?) I have worked with the Omnia 5EX-AM, Omnia 6 and Omnia 3 FM turbo and Omnia 3 AM in addition to the above.

The only boxes worth a damn with their AGC's are

Ariane with any of the above
Compellor/Prisms with the 8100
8100 by itself (the 8100 has a very natural sound barefoot)

None of the digital boxes have good front ends. Couple that with the fact that the jocks can't hear the TRUE on air mix and voila.

You would be amazed at how good the 8100 and the Ariane sound together. Everything is not smashed to hell, it is loud, it is consistant but not over the top. Very pleasing to listen to. It is the best sounding setup I have heard in a very long time. Everytime I listen to one of my other boxes, I always go back to that setup and it just sounds right. All elements always mix well. Also, the bass on the 8100 sounds better than the 6200, which adds too many tricks to get too much of a synthetic sounding bass. Keep it simple.

The days of listening to your air product in the studio are gone the HD digital. I can't speak for FMXtra or Cam-D but I would venture a guess that anytime compression of any type is added, buffering is an essential part of the transmit chain. IBOC delays the analogue audio so that it can seamlessly (if set up properly) segue into the digital transmission stream.

 

[dumber than a box of hair]

The days of listening to your air product in the studio are gone the HD digital. I can't speak for FMXtra or Cam-D but I would venture a guess that anytime compression of any type is added, buffering is an essential part of the transmit chain. IBOC delays the analogue audio so that it can seamlessly (if set up properly) segue into the digital transmission stream.

It's not just compression that introduces the delay. ANY type of DSP in the STL will introduce enough delay to make off-air monitoring impossible, even for an analog signal which uses a digital-radio STL or T1 link to the transmitter.

 

[R.F. Burns]

But in this case we're talking about an 8 second delay and for any descent HD station there is no compression used outside of HD encoder. Even at the network level linear is common place and spots are now played from a wav source rather than MP2 or MP3 to try and lesen the problem of cascading codecs.

 

[Mike Walker]

Delay is just a fact of life with digital. ANYTHING digital in the air chain, including processing for analog-only stations, produces some delay.

What do you do at your stations, RF? I know WFAE in Charlotte has "fake" processing for studio monitoring, so air talent still gets that "on air" feeling in headphones and speakers.

 

[R.F. Burns]

Delay is just a fact of life with digital. ANYTHING digital in the air chain, including processing for analog-only stations, produces some delay.

What do you do at your stations, RF? I know WFAE in Charlotte has "fake" processing for studio monitoring, so air talent still gets that "on air" feeling in headphones and speakers.

In our situation because of the type of operation I work at, we use Aphex analog processing right to the mux, which is at the uplink, converting analogue to digital. Our air staff listens to the audio out of the processing. In the case of production, the air staff listens to the output of the board. It's called watching one's levels.

 

[wgliradio]

The best thing to do is use the low latency delay out of your main on-air processor. If that is not possible because of location, I would, for sake of the sound of the station, buy another of the exact same processor, run the exact same preset and locate it at the studio.

 

[Chuck]

The best thing to do is use the low latency delay out of your main on-air processor. If that is not possible because of location, I would, for sake of the sound of the station, buy another of the exact same processor, run the exact same preset and locate it at the studio.

Most of the new digital processors insert enough of a delay to be disconcerting when you're listening to yourself on headphones. It bothers some people more than others.

 

[EasyPeazy]

Most facilities I've seen are using an old Optimod 8100 or Omnia.fm of some type to process their air monitors in the post-HD world. What the talent hears in their headphones should be close enough to the actual air signal to set appropriate levels.

When you hear problems like the ones described earlier in the thread, it's usually just lazy board work. I was in a studio a few weeks ago where the jock on the air and all of his cohorts were watching American Idol. He didn't bother to mute the rather loud TV before going on air. This was at a top 10 market CHR.

Keep in mind that many stations (mostly major market) run EVERYTHING through a profanity delay regardless of whether they're HD or not, so you can't lay the blame for this on HD Radio.

 

[davideduardo]

How on earth can you get a good mix on the air when you can't hear that's going out over the air IN REAL TIME!?! Do you have the processed signal sent back to the studio for that?

And what if there is completely different processing for analog and digital?

All digital processing has some delay. Digital processors... and this is simplification... delay the audio so that the processing can look ahead, then go back to the delayed audio and process it. Most of us with digital processors and other systems have not monitored off the air for a looooong time. We have equipment that does that. The day of the air monitor is long gone.

And analog is processed totally differently from the audio that goes on the digital signal. In part, and on FM, this is because digital HD audio has no preemphasis curve (thank goodness) so the processing must be different.

And, as Eazy mentions quite correctly, nearly all stations run a profanity delay 24/7 so there is just no way to do direct air monitoring, with or without HD radio.

 

[davideduardo]

But in this case we're talking about an 8 second delay and for any descent HD station there is no compression used outside of HD encoder. Even at the network level linear is common place and spots are now played from a wav source rather than MP2 or MP3 to try and lesen the problem of cascading codecs.

Not only that, the 8 seconds is needed to allow receivers to buffer rather than falling back to the analog audio.