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High Frequencies in processing

whit979

whit979

I'd like to get some of everyone's thoughts on a nuisance I have with our [FM] processing: high frequency sound (in the 'S' vocal range). Most of the out-of-the-box Rock presets I have tried (Optimod 8400) make the high end rather mushy/dull on most of the alternative stuff we play (Hot AC format). It only sounds decent on hip-hop, which I cannot figure out why.

I have always been impressed with the kind of HF sound that most stations have around us (i.e., Birmingham, Atlanta, etc.), seems to be boosted and present, but still clean. On our presets, Brilliance just seems to boost the dull sound. I have tried working with HF Enhance but I'm just not sure if I'm doing it right. I have also noticed the Band Mix controls in the 8400 and I'm wondering if that would make any difference.

What are some of everyone's thoughts on getting that sweet "big city" HF sound?

Kind regards,
Whit McGee
 
pre emp flat (off.)little john, would it not sound tinty? also i wonder if whit is running pre-emph in the 8400 and in the STL? that could be siphoning off some highs..never knew of anyone not running the 75 pre emph(usa) in the processor,since that seems to be the desired place to have it.
 
Once had a mosely STL that had the stereo gen and pre at the STL RECEIVE END. We ran unpreemphasized audio on the output of the processor into the digital STL and did final mod settings at the xmtr. Sounded good, loud, incredibly clean.
 
menotti1 said:
pre emp flat (off.)little john, would it not sound tinty? also i wonder if whit is running pre-emph in the 8400 and in the STL? that could be siphoning off some highs..never knew of anyone not running the 75 pre emph(usa) in the processor,since that seems to be the desired place to have it.
Click to expand...

Well, we're using the Composite Out to a Moseley analog STL. Does that make any difference?
 
Put the preemphasis back after you process the audio, of course. And no, properly done it doesn't sound tinny. Actually, for any format, there's at least one "Oh god" song. For country, I used to use Kenny and Dolly's "Islands in the Stream". When tyou got the thing where that song sounded pretty good, you were close. For classical, the fanfare from the third movement of DFalla's "Three Cornered Hat" will exercise the plant about as well as anything you might play. Actually, the London recording of it being done by the Vienna Stat Orchestra and chorus is a pretty good piece of test audio fro anything, if you can find it. Any intermod at all will very quickly be appareent. For a rocker, use something with a lot of loud and a continuous 'sizzler' cymbal beat. When the sizzle turns to white noise, back of about .5 and you will be close. If you do hiphop, be real sure you have an exciter with a very slow AGC loop. They sound terrible when the AGC unlocks and relocks on the thumps.
 
Sorry ,little john, slightly mis read your post.You were talking of about setting up the unit ,then putting back pre-emph, not as the final processing.another song used years ago for top 40 setup was Heatwave's Grooveline.Shame by Evelyn Champagne King is another one.
 
with digital processing, most of the time 'less is more'

start by backing off the AGC, limiting, and clipping until it 'sounds clean', then gradually bring them up until you start to hear bad things, then back it down a bit

at one station, I reduced overall AGC by 8 dB, limiting by 3 more, and clipping by another half dB, and the result was loud AND clean'

you might also back off the output into the exciter by 0.2-0.4 dB, a lot of exciters don't play well with '0' output from the processor

try it, what do you have to lose ?
 
Well I suppose I will have to give that a try. I had switched us to a louder preset for today, just to see how the increased clipping affected the high end. Still mushy, just more boost to the mushy sound now. We have a bunch of Clear Channel stations near us and for some reason their high end really sparkles. They have the 'perfect' high end sound that I'm looking for. Recommendations?
 
If it's Clear Channel in a bigger market, I'd be shocked if they're not using an Omnia 6.

But there could be a multitude of other reasons why your high end doesn't sound as good as theirs.

CC's music is compressed at about (i believe) 256kbps or 320kpbs @ a sampling rate of 48khz using mp2. So if you'd like to have a competitive sounding high end it starts with your source material. Playback all your music without any compression. That will give you some advantage.

What's your competition's modulation like? Some CC engineers, not all, think 125% is the new 103%. So if they're over the speed limit, they'll sound better (depending).

Go through your STL path for cleanliness and check for proper deviation using the appropriate expensive gear. Don't trust the front panel meter on your STL. Check it.

Sweep the STL lines. Check for co-channel or adjacent interference, take your STL down and look at the freq at the receive end on a spectrum analyzer. Is there garbage on or too close to your freq? You may be shocked. I was, once!

Is your main on-air transmitter tuned properly? What exciter are you using? How is it? How does the signal sound at the xmtr just running the exciter? What does the bare output of the processor sound like? How does the audio sound at the STL receive site? Does your high end sound the same on all radios or are you dissatisfied with it on just one?

Just letting you know, from experience, your dissatisfaction could be anything, but I'd start with your source material and getting an Omnia. While that could level the playing field: there is much more that happens after you hammer your audio.

Solid RF engineering and delivery has much to do with it, too. CC is pretty good in that area... in most of their larger markets, anyway.
 
Undo as much coupling in the upper bands as you can tolerate

Decrease the HF limiter thresholds as high as you can go before you can't tolerate it (band 4/5)

Decrease the attack times a little.

Play off these two settings.

TURN OFF THE HF ENHANCER. NO NO NO NO NO NO NO NO NO. That feature is a waste of time.
 
sgerik, hit the mark dead center.you can't hang with the omnia 6ex with a 8400.Plus the CC air chain is WAY more sophisticated than what you have.they are probably running linear uncompressed into the aes on the omnia,keeping the path as digital as possible.Your STL can't hang with what they are probably running.But one thing for sure is that 8400 may not be for you and you may not have ten grand for the 6ex,but you may look at the new Omnia one FM.It will have a street price of around 2500.00
 
Since were on the topic of 75 pre emph and STL's. Those of you out there running Starlink's or other digital STL's, where are you running the pre emph? on the processor or on the exciter? Does it make a difference on a digital system?
 
I have stations with Omnia 6's and Optimods 8300, 8400, 5300's. All of the architecture is the same between the Optimods. Overall, the Omnia is definitely brighter, but IMHO, more distorted than Orban. I do know that pre-emphasis is applied after multiband functions in the Omnia, and before multiband in the Orban stuff. I too get the complaint that on certain material the Optimod sounds dull. WGLI is right, try reducing the band 4-5 coupling a bit. In fact, every installation I have with Optimods I reduce down to 90% coupling on 4-5. That is usually enough to add some sparkle without sounding shrill. I may disagree with lowering the HF limiting function because that possibly could result in some HF overshoot that the clipper cannot handle. The HF enhancer doesn't sound good at all, so I agree with WGLI with that as well. Turn that off. Also, are you using the stereo enhancer? I have found that 2 or 2.5 is plenty. Any more and it actually sounds duller to me, and probably doesn't help with multipath. Another thought is the 15 kHz low pass filter in the Optimod is rather steep. The Omnia is very gentle, so there is more energy above 15 kHz with the Omnia. With the 8500, I believe Bob matched Omnia with a very gentle low pass filter. I may be wrong on that.
 
fm-engineer said:
I have stations with Omnia 6's and Optimods 8300, 8400, 5300's. All of the architecture is the same between the Optimods. Overall, the Omnia is definitely brighter, but IMHO, more distorted than Orban. I do know that pre-emphasis is applied after multiband functions in the Omnia, and before multiband in the Orban stuff. I too get the complaint that on certain material the Optimod sounds dull. WGLI is right, try reducing the band 4-5 coupling a bit. In fact, every installation I have with Optimods I reduce down to 90% coupling on 4-5. That is usually enough to add some sparkle without sounding shrill. I may disagree with lowering the HF limiting function because that possibly could result in some HF overshoot that the clipper cannot handle. The HF enhancer doesn't sound good at all, so I agree with WGLI with that as well. Turn that off. Also, are you using the stereo enhancer? I have found that 2 or 2.5 is plenty. Any more and it actually sounds duller to me, and probably doesn't help with multipath. Another thought is the 15 kHz low pass filter in the Optimod is rather steep. The Omnia is very gentle, so there is more energy above 15 kHz with the Omnia. With the 8500, I believe Bob matched Omnia with a very gentle low pass filter. I may be wrong on that.
Click to expand...

Excellent. I will have to try that out. So basically just relying on 4-5 coupling and Brilliance control....what's a good average number there, if you could throw one out?
 
I know this is a time investment but.. Why not give Orban support a call, they may have a solution for you.

With Omnia, I've called support on a few occasions and they've walked me through any questions I've had. Three stations all running crystal clear audio with Omnia.

Give it a try!
 
running digital stl or not ,i would always do the pre-emph in the processor.otherwise i think it would degrade the sound.locate the processor at the xmtr and use a pre like ariane at the studio..or an external sg..
 
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