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LPFM Audio Processsing
- Thread starter BostonRadioDJ
- Start date
Peter Q. George (K1XRB) said:
I tried a PTEK a couple of years ago on one of my translators. Upon arrival, I noticed it was not the same unit as shown in the brochure or website -- the metering had been "economized" and it lacked the FSK ID-er that was supposed to be included. I pulled the top cover to check for any shipping damage (as I usually do), a fairly easy job as this cover was secured with only 4 screws. I was surprised -- no, shocked -- to find no shielding around the PA board. Everything was just mounted out in the open, the PA was right next to the audio/FMO board, etc. I guess that how they make them cheap. Put the cover back on and later than evening, we put it on the air. It sounded horrible in comparison to the Armstrong/RVR FMX-300B it replaced (which we were planning to re-use at another site), but I decided to leave it running overnight.
Next morning on the way up the hill, I noticed it was throwing spurs within +/- 2 MHz or so. That was the final indication that I should take it out, send it back, and forget about buying another PTEK.
Thought maybe ptek improved along the way.Heard good things about the gamma units,but the early ptek's had issues.One i remember had more spurs than Roy Roger's boots...
We (WLRE-LPFM) use a high quality sound card in our computer system then pre processing software and an optimod 8100a for final processing. We are as loud as any station and have better cleaner highs and seperation than most any other station in our area or surrounding areas. I am glad to hear that there are other LPFM's are kicking butt audio wise too.
A tidbit of info for the new & future Omnia.9 owners... my "Big Iron" preset in the 9 was inspired by the BIG am days. And to a degree, air checks from Tom's setup, which uses certain analog gear to get the dynamics heuristics it has.Tom Wells said:
p.s. Tom has some of the best classic AM imaging/production I've heard in a while.
Goran Tomas said:
You'd be surprised. 6 years ago I installed an 8100/Ariane combo here on LI that creamed stations running 8400's and Omnia 6's. How? The other boxes have so many tweaks the adjusters had gotten into the weeds and it was easy to just set up the 8100 and go.
The station had been running the 8100 with prisms and a CP803. I tore those out to install the analog Ariane and the station retained loudness and was much more open without the CP 803.
No composite processor in the 8100, stock cards... it does have card 0.
Fast forward to yesterday when I'm here visiting and the station with the 8100/Ariane combo STILL sounds about as loud as the others (and many times AS loud), yet it's much better to listen to because it's not as crunched. The two other FM's still have the 6 and 8400, and they're a bit better, but they still don't have it "right".
All of these FM's are within earshot of NYC and the 8100 has a noticable loudness disadvantage to SOME of the city FM's. But again, even in NYC, you find some stations are in the weeds with their audio and the 8100 is an overall easier box to listen to than those.
Next month the 8100 gets yanked for a better box after 20 years of service. I'll have fun tuning that up
Mike, I love the 8100... With the XT2 chassis, that would be my preference I just love it's warmth, smoothness , naturalness and I will agree with you it can be competitive.
But put it on the bench with the modern DSP processor next to it and loudness wise, there's really no comparison. None at all. And I don't care how much pre and post processing you put to go along with it...
What you mentioned there are 10 year old boxes such as Omnia 6 and 8400... Have you've heard any of the latest processors? Have you heard the Omnia 11, for example? Have you heard how loud and clean it is?
Having said the above, yes, it is possible for your station with Ariane/8100 to sound better than other stations... As I'm sure you know, although very important, a processor is a piece of the puzzle called broadcast chain. And there are many factors there that can make a good processor sound weak and a weak processor sound good.
Just take an STL as an example. I've seen STLs that have so much overshoot that they would put the loudest processor on Earth into the minors league, if you set it so none of the overshoots are above the 75kHz. Recently we've replaced a composite STL on a station and got so significant improvements in peak modulation, it seemed like they went from 4k processor to 14k one. And there were sonic improvements with the new STL as well. If you drive the transmitter directly from the processor on your LPFM, then this crucial variable that can break your chain, is out of the way. Then there are exciters, how you feed the processor, how is it connected to your console, what is your source material, how and in what conditions are you receiving this, what is your modulation, what are your pilot and RDS levels... And last but not least - who's adjusting the knobs and how the processor is set up!
All of which is why you never ever judge a processor based on how it sounds on some station you listen on-air! There's way too many variables... And any of them will skew your impression significantly.
The above poster said his 8100 sounds better than any other station in the market. Under the assumption that there's at least one station in the market with the bigger, more expensive processor and that they are competent enough to have their transmission chain set-up carefully and correctly and performing optimally, and the poster is not over-modulating, then there's simply no chance he can sound better... I mean louder and cleaner. Better is subjective
Regards,
Goran Tomas
I just love it's warmth, smoothness , naturalness and I will agree with you it can be competitive. But put it on the bench with the modern DSP processor next to it and loudness wise, there's really no comparison. None at all. And I don't care how much pre and post processing you put to go along with it...
What you mentioned there are 10 year old boxes such as Omnia 6 and 8400... Have you've heard any of the latest processors? Have you heard the Omnia 11, for example? Have you heard how loud and clean it is?
Having said the above, yes, it is possible for your station with Ariane/8100 to sound better than other stations... As I'm sure you know, although very important, a processor is a piece of the puzzle called broadcast chain. And there are many factors there that can make a good processor sound weak and a weak processor sound good.
Just take an STL as an example. I've seen STLs that have so much overshoot that they would put the loudest processor on Earth into the minors league, if you set it so none of the overshoots are above the 75kHz. Recently we've replaced a composite STL on a station and got so significant improvements in peak modulation, it seemed like they went from 4k processor to 14k one. And there were sonic improvements with the new STL as well. If you drive the transmitter directly from the processor on your LPFM, then this crucial variable that can break your chain, is out of the way. Then there are exciters, how you feed the processor, how is it connected to your console, what is your source material, how and in what conditions are you receiving this, what is your modulation, what are your pilot and RDS levels... And last but not least - who's adjusting the knobs and how the processor is set up!
All of which is why you never ever judge a processor based on how it sounds on some station you listen on-air! There's way too many variables... And any of them will skew your impression significantly.
The above poster said his 8100 sounds better than any other station in the market. Under the assumption that there's at least one station in the market with the bigger, more expensive processor and that they are competent enough to have their transmission chain set-up carefully and correctly and performing optimally, and the poster is not over-modulating, then there's simply no chance he can sound better... I mean louder and cleaner. Better is subjective
Regards,
Goran Tomas
Goran
I think you may have missed the point of my post. My comments basically stated that you can drive an older box past newer tech in many markets where those boxes may be misadjusted. And, yes, it depends on factors such as source material and the entire airchain as a whole. If anyone would have stepped up to the plate in the situation I mentioned and actually found someone to adjust those other boxes, or if quality control of their pant became a priority, we would have probably had to make a hardware change.
And, yes, I've heard all of the new boxes and spend time with them almost daily.
I think you may have missed the point of my post. My comments basically stated that you can drive an older box past newer tech in many markets where those boxes may be misadjusted. And, yes, it depends on factors such as source material and the entire airchain as a whole. If anyone would have stepped up to the plate in the situation I mentioned and actually found someone to adjust those other boxes, or if quality control of their pant became a priority, we would have probably had to make a hardware change.
And, yes, I've heard all of the new boxes and spend time with them almost daily.
Usually I'll ask the customer what their source files are and there's that awkward moment of silence as they admit its MP2/MP3.
Their mindset is that their older processor sounded only *this* good with the coded audio and that a new processor should sound *this* much better. It doesn't work that way.
On the road I've seen some odd things. Problem is, every engineer has their ideas about how things should be. Alot of times it works out VERY well. Other times, either thru misunderstanding or just stubbornness, bad ideas get implemented and don't change easily.
I actually had a customer who was using a bunch of RDL stick-on DA's before the processing. He wondered why the balance was drifting with his old box. Yet another was using their old processor at the studio, sending the audio over a Barix box and using an old analog stereo generator at the transmitter. This was in a Top 20 market.
The old processor at the studio was a fully competent box that could have easily been remoted at the TX site which had internet connectivity. The excuse for keeping it at the studio was to have access to adjust it. It took a bit of persuading but I got him to move both the old and new boxes to the TX and he's now very happy. The key was not to tell him it was "horribly wrong", it was suggestion about the age and technology in that old stereo generator and challenging him to make use of the new technology in his new box and the infrastructure he had available to control the box from a remote location.
Their mindset is that their older processor sounded only *this* good with the coded audio and that a new processor should sound *this* much better. It doesn't work that way.
On the road I've seen some odd things. Problem is, every engineer has their ideas about how things should be. Alot of times it works out VERY well. Other times, either thru misunderstanding or just stubbornness, bad ideas get implemented and don't change easily.
I actually had a customer who was using a bunch of RDL stick-on DA's before the processing. He wondered why the balance was drifting with his old box. Yet another was using their old processor at the studio, sending the audio over a Barix box and using an old analog stereo generator at the transmitter. This was in a Top 20 market.
The old processor at the studio was a fully competent box that could have easily been remoted at the TX site which had internet connectivity. The excuse for keeping it at the studio was to have access to adjust it. It took a bit of persuading but I got him to move both the old and new boxes to the TX and he's now very happy. The key was not to tell him it was "horribly wrong", it was suggestion about the age and technology in that old stereo generator and challenging him to make use of the new technology in his new box and the infrastructure he had available to control the box from a remote location.
Re: LPFM Audio Processing
I started consulting for an am/fm combo about 3 years ago, fm was using a decent processor on the studio end of a poor composite stl, on a bad path at that, so bad that noise would be heard on the air when the wind blew the trees around.
the am was on a subcarrier on this stl, with so much crosstalk on it the fm audio was only maybe 15-20db down from the am audio. Unfortunately, I had to run this way for a while to convince the owner that some things needed to change, I was able to adjust the composite modulation way down, run the subcarrier way hot and get the crosstalk to a minimum. The other important factor to note here is there was not a backup for anything there, lost a processor, had to borrow an old 8100 to stay on the air legally, I actually had to run with just a dbx 266xl attempting to control the audio level going out, source material was good and consistent level so it wasn't too bad.
it took me around 2 years of part time work while maintaining a full time job to really straighten things out like they need to be. A lot of that time was ripping out piles of relays with 120v ac coils that were in audio paths, with uninsulated contacts. After getting the crap knocked out of me a few times digging around troubleshooting, I convinced the owner that needed to go. this was for the am, which is all network talk programming, instead of getting a proper audio switcher, the previous engineer opted for timers and relays.
On to today, they are in a new studio, I used a digital snake product from networksound, really designed for live sound applications, they were able to configure me a 32x16x16 split, thats 32 channels from rack to both control rooms and 16 channels from each control room back. Over a single cat5. there was not money for full blown ip audio such as axia's livewire product so this is what I got. Processing for the am was upgraded, went to an aphex compellor at studio, feeding barix instreamer, 900mhz wireless link, exstreamer, omnia one. that cleaned up the audio drastically. There is now a 950mhz mono stl for backup on the am. The fm is now on a t1 circuit with cisco 2610 routers on each end, bridging ethernet from studio lan, comrex bric-link feeding aes to processor as the tower strobe power supply is right next to our rack and caused some noise in an analog audio line. We also have a backup path here which is a 950mhz composite stl from the am site, fed by another barix pair as there is no line of sight from the studio location to fm.
We also installed a generator at the fm transmitter site, it was an old used generator, I had to engineer my own controls and such for it, it was 3 phase but wired for single from the factory so I had to add in a 3 phase monitor to insure protection if one phase is lost. that has worked beautifully, since this was all implemented, off air time has been limited to time for the generator to start + filament warmup timer.
T1 circuit used to go down all the time, once backup path was re implemented from new location, as murphy will have it, t1 hasnt even blinked since then. If it does, backup path is always active, silence sensor at FM site controlling a coax relay with both feeds connected, it automatically falls over to backup in 10 secs, has to manually be switched back via remote control.
even I'm amazed at how things work when done right, especially by someone thats never been involved in broadcasting until this owner gave me a chance to "learn the ropes" I took the opportunity and ran with it, now I'm associated with the best sounding signal in our market, possibly in the state. And its always on air, come hell, high water, whatever mother nature brings, we're usually the only stations left on the air.
And as such, have been designated as the city's official information outlet for the area. They are about to deliver a radio to us programmed to a special talk group for emergency information, a few key officials will have the dtmf codes necessary to trip a relay to put that radio directly on air to get emergency information out to the public.
I started consulting for an am/fm combo about 3 years ago, fm was using a decent processor on the studio end of a poor composite stl, on a bad path at that, so bad that noise would be heard on the air when the wind blew the trees around.
the am was on a subcarrier on this stl, with so much crosstalk on it the fm audio was only maybe 15-20db down from the am audio. Unfortunately, I had to run this way for a while to convince the owner that some things needed to change, I was able to adjust the composite modulation way down, run the subcarrier way hot and get the crosstalk to a minimum. The other important factor to note here is there was not a backup for anything there, lost a processor, had to borrow an old 8100 to stay on the air legally, I actually had to run with just a dbx 266xl attempting to control the audio level going out, source material was good and consistent level so it wasn't too bad.
it took me around 2 years of part time work while maintaining a full time job to really straighten things out like they need to be. A lot of that time was ripping out piles of relays with 120v ac coils that were in audio paths, with uninsulated contacts. After getting the crap knocked out of me a few times digging around troubleshooting, I convinced the owner that needed to go. this was for the am, which is all network talk programming, instead of getting a proper audio switcher, the previous engineer opted for timers and relays.
On to today, they are in a new studio, I used a digital snake product from networksound, really designed for live sound applications, they were able to configure me a 32x16x16 split, thats 32 channels from rack to both control rooms and 16 channels from each control room back. Over a single cat5. there was not money for full blown ip audio such as axia's livewire product so this is what I got. Processing for the am was upgraded, went to an aphex compellor at studio, feeding barix instreamer, 900mhz wireless link, exstreamer, omnia one. that cleaned up the audio drastically. There is now a 950mhz mono stl for backup on the am. The fm is now on a t1 circuit with cisco 2610 routers on each end, bridging ethernet from studio lan, comrex bric-link feeding aes to processor as the tower strobe power supply is right next to our rack and caused some noise in an analog audio line. We also have a backup path here which is a 950mhz composite stl from the am site, fed by another barix pair as there is no line of sight from the studio location to fm.
We also installed a generator at the fm transmitter site, it was an old used generator, I had to engineer my own controls and such for it, it was 3 phase but wired for single from the factory so I had to add in a 3 phase monitor to insure protection if one phase is lost. that has worked beautifully, since this was all implemented, off air time has been limited to time for the generator to start + filament warmup timer.
T1 circuit used to go down all the time, once backup path was re implemented from new location, as murphy will have it, t1 hasnt even blinked since then. If it does, backup path is always active, silence sensor at FM site controlling a coax relay with both feeds connected, it automatically falls over to backup in 10 secs, has to manually be switched back via remote control.
even I'm amazed at how things work when done right, especially by someone thats never been involved in broadcasting until this owner gave me a chance to "learn the ropes" I took the opportunity and ran with it, now I'm associated with the best sounding signal in our market, possibly in the state. And its always on air, come hell, high water, whatever mother nature brings, we're usually the only stations left on the air.
And as such, have been designated as the city's official information outlet for the area. They are about to deliver a radio to us programmed to a special talk group for emergency information, a few key officials will have the dtmf codes necessary to trip a relay to put that radio directly on air to get emergency information out to the public.
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