Optimod 8100 Lesson

[Kmagrill]

The Prisms can be placed in front of a stock 8100 with great results if:

(1) You put something like a Compellor or other leveler in front of the Prism to keep them in the sweet spot and (2) you let the prisms do all the compression. The 8100 should be running no more than 2-3 db of total gain reduction. Pay particular attention to the “presence band” of the prisms.

That was the most common method used back in the 80s. Everyone tried that method, but I never liked the results at all. The key to analog loudness is fast and deep limiting. Compression results in a busy sound, but doesn't produce much percieved loudeness. In the Compellor ->Prism ->Optimod scheme, you have two compressors in the Compellor and Prisms and one limiter in the Optimod which is being under-utilized.

I used to drive the competition insane by using the Prisms more as dynamic EQs with very light compression (low density settings) and driving the Optimod hard into 10-15 db of limiting and running at its fastest settings. It's always louder that way, and it doesn't suffer as much from that busy sound that compression produces.

 

[chriscollins]

The Prisms can be placed in front of a stock 8100 with great results if:

(1) You put something like a Compellor or other leveler in front of the Prism to keep them in the sweet spot and (2) you let the prisms do all the compression. The 8100 should be running no more than 2-3 db of total gain reduction. Pay particular attention to the “presence band” of the prisms.

That was the most common method used back in the 80s. Everyone tried that method, but I never liked the results at all. The key to analog loudness is fast and deep limiting. Compression results in a busy sound, but doesn't produce much percieved loudeness. In the Compellor ->Prism ->Optimod scheme, you have two compressors in the Compellor and Prisms and one limiter in the Optimod which is being under-utilized.

I used to drive the competition insane by using the Prisms more as dynamic EQs with very light compression (low density settings) and driving the Optimod hard into 10-15 db of limiting and running at its fastest settings. It's always louder that way, and it doesn't suffer as much from that busy sound that compression produces.

I agree totally with that statement. The 'busy' sound you speak of is very fatiguing to people (especially females). It isn't perceived until you listen for a while, but you WILL eventually flip away, regardless of the content.

 

[radiosaur]

Well, all I can say it we beat the crap out of the Optimod XT across the street with that combination, both in audio quality, loudness, and ratings. Female numbers were huge.

 

[oldiesstation]

3-5db total GR sounds good to my years.I;ve slammed it down in the 10-15 before,just did not like it..you know the drill,less is more.

 

[WNTIRadio]

Translators can receive interference, but they cannot cause it. Usually, the FCC only considers complaints from listeners inside of the service contour of the affected station.

It's incredibly hard for a translator to get displaced, if the translator operator knows what they are doing. The affected station has to show listener complaints and those listener complaints cannot be solicited in any way by the affected station, they must be completely spontaneous. Any connection of the listeners to the station, even if they only reponded to a call for listeners to speak up about interference that they might be having, invalidates the listener responses. Chances of your translator, as a first adjacency, resulting in spontaneous listener complaints is very low. In the very rare case that this actually happens, the FCC will usually let the translator make a major change via minor change application on the grounds that displacing the translator is less of a public benefit than breaking a rule and allowing it to make a major change.

Is this a rule in the FCC? Reason I ask is that 106.3 here in NJ solicited people to complain on their website and on air, and did effectively get the 106.3 in NYC shut down after a week and a half.

I have a few translators in my care and was displaced on one when a full power A signed on about 10 miles away. The rest have been there for years with no problems or issues.

 

[Kmagrill]

Wrong thread, but the answer is it's not a rule, it's a policy. Policies can be altered, but as far as I know, this is the current policy.

I got the information from an AFCCE engineer that I know. He was confronted with this issue for one of his clients recently and they were able to get the FCC to dismiss all complaints received over a period of time because they had been solicited.

In the case of potential displacement, if the translator is threatened and any other channel is open on the commercial part of the band, it is supposedly possible to change channels. I have not had to try this, but I'm told it has been done before.

 

[Kmagrill]

3-5db total GR sounds good to my years.I;ve slammed it down in the 10-15 before,just did not like it..you know the drill,less is more.

I think that depends on how much compression is applied before hand. If very little compression is being done, then 10-15dB of limiting can be quite acceptable, but that's only in my opinion. I prefer that sound because it's loud but sounds more open to me.

 

[Kmagrill]

Well, all I can say it we beat the crap out of the Optimod XT across the street with that combination, both in audio quality, loudness, and ratings. Female numbers were huge.

I would believe that. I could never get a sound from an Optimod 8100 with XT chassis that didn't sound squashed. Any combination of Prisms with an Optimod would be preferrable. Maybe your station's programming was better, too?

 

[chriscollins]

Well, all I can say it we beat the crap out of the Optimod XT across the street with that combination, both in audio quality, loudness, and ratings. Female numbers were huge.

Then, you obviously have your combo setup correctly. Most PD's dig the squishy sound and try to get their station to sound like that, not realizing the consequences. I didn't say the combo couldn't sound good. I said I agreed that it can get too busy.

 

[oldiesstation]

Adjust for taste.I have my own favorite recipe!! Squashed sounded good in the 80's..

 

[rrsounds]

Well, all I can say it we beat the crap out of the Optimod XT across the street with that combination, both in audio quality, loudness, and ratings. Female numbers were huge.

I would believe that. I could never get a sound from an Optimod 8100 with XT chassis that didn't sound squashed. Any combination of Prisms with an Optimod would be preferrable. Maybe your station's programming was better, too?

It was my conclusion (with confirmation from my processing guru pals Gary Blau and Greg Strickland) that the real power in the XT was not its limiters, but rather its clippers. By modifying the limiters to be very slow, but driving relatively deep into the amazingly transparent distortion-cancelling clipping, one could get great openness and loudness at the same time. In my case this involved creating individual threshold trim controls for each band, and removing, or replacing with much larger values, all the release time constant resistors.
I ran the front panel controls flat, i.e., no EQ boost. Didn't need it.

This set of modifications, along with de-peaked Texars, was in use for a while when I was CE at Z100.

Kind Regards,
David

 

[gtomas]

Well, I would say it wouldn't be good if people reading this would generalize that less compression and more of fast limiting gets you an open sound... It really all depends on which compressor and which limiter - what processors are used as well as what kind of clipper are they driving. AGCs, compressors and limiters tend to sound quite different between different units and what works in one processor (ie. more compression, less limiting or the other way around) might not work in the other.

By modifying the limiters to be very slow, but driving relatively deep into the amazingly transparent distortion-cancelling clipping, one could get great openness and loudness at the same time.

I definitely agree that the sound of the XT(2) becomes more open and has more depth when the release is slowed down. As you've said, you can keep the same loudness by driving the limiters more.

However, on the station I worked at, I had to revert that modification back to the original timings. The DJs and board operators didn't like that the processor did less level control and equalization with the limiters slowed down. They were used to smashing the jingles and other elements into the "spongy wall" that the original XT2 would provide. With the limiters slowed down, the effect was not there - it was all softer. Too soft. It's not that people working the board were sloppy (like many guys today) but we've actually used it as effect. The 8100/XT2 combo has a nice characteristic that things get tighter, when you drive it harder. If you know how to use this and how to play it, it becomes a tool when you're mixing the live show. You can have a nice open sound when you're playing music, but you can also compress and pack a lot of sound, when it suits the program. But I'm afraid that the days of people mixing live on the air and using the processor as a tool, might be gone...


Regards,
Goran Tomas

 

[WNTIRadio]

Let's all remember that when the XT-2, Prisms etc. were all designed, the music being run through them wasn't a clipped mess like the music of today. If the source material had 15-20dB of dynamic range or more, you could do a lot more to it at the processor end without turning it into a wall of sound.

Now, everything is over-mastered and clipped to death before it even gets to your audio processor. It's almost like running some songs though the smash box twice.

 

[chriscollins]

Let's all remember that when the XT-2, Prisms etc. were all designed, the music being run through them wasn't a clipped mess like the music of today. If the source material had 15-20dB of dynamic range or more, you could do a lot more to it at the processor end without turning it into a wall of sound.

Now, everything is over-mastered and clipped to death before it even gets to your audio processor. It's almost like running some songs though the smash box twice.

Yep. I emailed all of my record reps about that to no avail years ago. I did, however, convince many of them that I needed the original mastered .wav instead of the mp3 they wanted to send me.

If I am in a music sweep, I can flip off the AGC in my 8300 and it is virtually no difference in sound.

 

[Kmagrill]

It was my conclusion (with confirmation from my processing guru pals Gary Blau and Greg Strickland) that the real power in the XT was not its limiters, but rather its clippers. By modifying the limiters to be very slow, but driving relatively deep into the amazingly transparent distortion-cancelling clipping, one could get great openness and loudness at the same time. In my case this involved creating individual threshold trim controls for each band, and removing, or replacing with much larger values, all the release time constant resistors.

Orban's clippers were amazing. I always considered them to be part of the limiter circuit, but of course, they are really after it.

Now for a question for the experts. Since the clippers don't produce much significant distortion, could that design be used to drive streaming audio without the affects that a normal analog clipper has on the lossy compression?

 

[gtomas]

Since the clippers don't produce much significant distortion

But they do... Every clipper produces harmonic distortion. If it didn't, it wouldn't perform the clipping function. It's just that the distortion products of the multi-band clippers in the XT2 chassis are contained within that band. Indeed, the out-of-band harmonics are filtered out, but this also reduces the clipping effect.

It's the distortion-cancelled clipper (together with the overshoot compensator) that provides final peak control in the 8100A. And I would agree it performs very well.

You could use the 8100A or the 8100A with the XT2 for streaming, if you would apply only modest amounts of clipping. How much would depend on which codec and especially, how low bitrate are you using for your stream. If you don't generate too much distortion and you use high enough bitrate for the stream, chances are the codec won't rear it's ugly head. You also have to be aware of is that 8100A always uses pre-emphasis, which will emphasize the part of the spectrum that codecs are most sensitive to - the high frequencies.

So it would have to be a very delicate balance and the question is how competitive your stream will be compared to streaming processors with proper look-ahead limiting and codec-aware processing and will you be happy with the final sound. Typically what is considered "radio sound" requires some definitive 'wall' for the transients to be shaved off and give that effect.


Regards,
Goran Tomas

 

[FFoti1]

Now for a question for the experts. Since the clippers don't produce much significant distortion, could that design be used to drive streaming audio without the affects that a normal analog clipper has on the lossy compression?

In a word...NO! Codecs are extremely sensitive to harmonic distortion (THD), and recent study has shown they don't like intermod distortion (IMD) either. Clippers generate both THD and IMD.

I have found various dynamic peak limiters where the timing was quite fast, and that alone, generated annoying coding artifacts. I'd stay away from using any form of clipping in front of a codec.

-Frank Foti

 

[rorban]

Bob,

I have often wondered why you don't just throw in an 8100/XT2 Preset with the basic settings, just for everyone that wants it...

The multiband compressor/limiter in the Orban DSP-based audio processors is basically a hybrid of the XT2 and Gregg Labs sounds and represents what Greg Ogonowski and I felt to be the strongest points of each. One reason why we allowed the release times to be slowed way down compared to the XT2 is that Greg tended to prefer working the multiband clipper harder and letting the multiband compressor sound more open, which is a strategy others have discussed earlier in this thread.

You can get an Orban DSP processor closest to the XT sound by setting the MB Release control to Fast, using fairly fast AGC release times, and driving the multiband compressor quite lightly (about 5 dB of gain reduction). In other words, the AGC does a lot of the compression and the multiband compressor is treated mainly like a multiband peak limiter. With Fast release times, increasing the drive to the multiband compressors starts to produce a "wall of sound" effect once you go beyond about 5 dB of gain reduction.

All currently-made DSP-based Orban processors (including the 5500) have intelligent clipping distortion controllers that allow leeway in adjusting the multiband compressor for color. This feature was first introduced in the 8400 and quite dramatically improved in the 8600. Before the 8400 (i.e., the XT2 and 8200), the multiband compressors had to be carefully tuned to prevent difficult program material from sounding ugly when it hit the clippers. This is why there were no user-adjustable attack time or threshold controls in the 8200 -- Greg and I created presets based on a very large number of listening hours with challenging program material and concerned ourselves mainly with setting the multiband attack time and threshold controls to prevent distortion.

If you *really* want to emulate the XT2 sound (along with the sensitive multiband compressor tuning requirements that go with it), you can start with one of the "ultra-low latency" (UL) presets on a modern Orban processor. For the sake of achieving lowest delay, the UL presets do not include the intelligent clipping distortion controller, so the settings of the multiband compressor attack and threshold controls are critical for controlling clipping distortion, just as they were in the XT2. However, I would consider working with the UL presets to get a competitive sound in the year 2011 to be an exercise in masochism, given the availability of the intelligent clipping distortion controller in the non UL presets and the freedom that this feature gets you when you are customizing sounds.

As someone who was heavily involved in the design and tuning of the XT2 and 8600, both of which represent the "top of the line" FM processing product at a certain time in Orban's history, I strongly prefer the 8600 because it solves a lot of the problems that we were still struggling with in the days of analog. The 8600 can be substantially brighter, cleaner, and punchier than the XT2 while offering far tighter baseband spectrum control. As mentioned above, the 8600 allows much more leeway in adjusting the multiband compressors for color without worrying about unexpected distortion with certain program material.

I feel no nostalgia for analog; DSP allows me to do things that were simply impossible in analog. Moreover, because the features execute on DSPs instead of in drift-vulnerable analog circuitry, I know that every processor of a given model will sound the same, both when new and after is has been on the air for 10 years.


--Bob Orban

 

[HadYourPhil]

Where else on planet Earth would you get a Frank Foti-Bob Orban segue... I learn a lot from both you guys!!

 

[OKCRadioGuy]

Very cool indeed!