Okay, I apologize ahead of time... I am a GM not an Engineer

[SandySanford]

Okay, I am General Manager of a group... so that tells you that I know nothing about radio. That's not necessarily true, but engineering is not my strong suit! However, after 15 years in the business, I did learn a little along the way.

It's 10pm on a Friday and I have a problem that I am curious to find the answer to...

I am using left and right STL's to send my signal from the studio to the txmtr site. Once I get the signal to the txmtr site, I use two STL Receivers and run them into an Orban Optimod 8100 processor. I come out of the Orban Composite (using BNC Connectors) to the Exciter

HERE'S THE QUESTION... The Orban is older than my morning show team's jokes! Is there a better way to combine the two STL signals to composite? Also, I have no idea why the exciter (Harris Digit CD) is running analog but it is? Other information: I would like to run my RDS Generator as well. Should I just shut up my whining and keep using the Orban (which does no processing, all of that is done on the studio side) or is there another way... How much is a multiplexer compiler?

I am sure that I have not given you enough information... but if you can decipher my question, I appreciate any help

B.A. "Sandy" Sanford
Regional Manager
Noalmark Broadcasting Corporation

 

[LA_Guy]

Don't apologize, Sandy. I've been a GM and an owner before. I'm sure that you are a far better GM then I was!

There's nothing inherently wrong with running a dual mono STL. There's nothing wrong with an Orban 8100 either...except for this:
These pieces are probably pushing 20 years old. The capacitors in them dry out in about ten years. This affects (degrades) all aspects of the sound.
Also, the IC amplifiers in the Optimod (and lilkely your STLs as well) are probably TLO-72's, which were great for their time (1975) but have since been made obsolete by better performing (sounding) devices.

You have two options-depending upon your competitive situation.

The cheapest option would be to get the old equipment upgraded. Many engineers do this type of work (including me!). Rebuilding and rechipping the 8100 would cost you about $1000.00. Orban will replace all worn out parts and realign the unit (but not upgrade any ICs) for about $400.00. I consider this to be a bargain! The STLs can be also rebuilt for about the same cost. Also depending upon the brand, they can sometime be converted to composite operation, which would let your put your processor (and your RDS unit) at the studio.

Your next option would be to buy a new audio processor. Both Orban and Omnia have entry level digital units that run rings over many older analog units (but not a rechipped 8100-IMHO depending upon format that can be the best you can have!). Both will also allow auditions of their products. The units cost in the low $2K range.

DO NOT go into a Digit exciter digitally! You WILL NOT like the sound! Stick with the BNC composite input you have. Also, make sure that you have the correct ANALOG input card for the Digit. The digital input card can be run in "emergency mode" that will allow an analog input, but you'll only get 14 bit accuracy that way-as opposed to the full 16 bit resolution the analog input card gives you.

Finally, you might consider using an alternate form of STL. A pair of Barix Instreamers and Exstreamers sound great at high bit rates and can easily be sent over a DSL Internet connection or 5 gHz unlicensed link. Someone even sells a complete package for under $1500.00 (look at the other STL posts here).

If I can be of any more help, message me. Good luck.

 

[Doctor_Technical]

Sandy I can probably help with the RDS side - that's what I do for a livin'. PM me or just ask away right here.

Paul E. Burt, VP Broadcast Operations
AlertFM / GSS, an RDS-based alerting company

 

[SML]

Hi Sandy. The dual STL system you have in place is actually a very reliable way to deliver excellent quality stereo audio to the transmitter. Having the stereo generator/audio processor at the transmitter site results in a lower background noise level on your air signal than other analog systems. However, like everyone else has said, the age of your equipment is a cause for concern, as component aging will begin to take a toll more and more as this stuff ages.

If it is all working OK right now, you should begin planning on either rebuilding or replacing the older gear. You can get a loaner Optimod while the 8100 is being rebuilt, or buy a newer processor, which may please your audience's ears. The microwave links do not cost you in monthly fees, as compared to leased audio pairs or T-1 lines, so it is the easiest on your budget long term.

Depending on your cash flow, putting aside a certain amount every month for engineering needs will mean you have a capital account to use in a year or so to do these upgrades without a big hit to the bottom line. This is just good engineering practice, and a wise investment.

 

[RadioMan203]

Depending on your cash flow, putting aside a certain amount every month for engineering needs will mean you have a capital account to use in a year or so to do these upgrades without a big hit to the bottom line. This is just good engineering practice, and a wise investment.

Especially if you're a small radio group and tend not to have anything around for a backup in case of a lightning strike, etc.

 

[gtomas]

As others have pointed out, the things to check would be the age, condition and performance of STLs and the 8100 acting as a stereo generator. It would be good to know what kind of STLs you are using and what kind of main processing you have in the studio feeding the STLs?

What I would do first is check the performance of the STLs and realign, recondition them if necessary. Then you have two options:

1) Either keep the current arrangement with the main processing at the studio and a) look into re-furbishing 8100 that you're using as a stereo generator or b) buy a new digital stereo generator. We have a stereo generator called DSPmpx with overshoot compensated clipper, 15k filtering, high-performance stereo generator and composite clipper, but you can get one from Orban or Omnia as well.

2) Consider moving your main processing from the studio to the transmitter site and putting a leveller (such as Ariane Sequel) in the studio for STL protection. You can then keep the 8100 as a backup processing.

As Dana pointed out, you want to stay away from Digit's AES/EBU input...


Regards,
Goran Tomas

 

[TomT]

I'm coming from the ownership side as well as the engineering side, so my position is a little different. I don't like spending money if I don't have to, I don't like complicated if simple will do, since I have to fix the stuff if it breaks.

1. How important is the RDS, and what are you wanting to do with it? I have the $350 Inovonics generators that just give me 8 lines--these go out at the transmitter and just run the same message over and over. Since I'm satellite, I don't have anything else to feed them anyway. If you can feed song and title it is a nice feature, but then the puzzle is how to get that information from studio to transmitter.

Therefore:

A. If the RDS is low on the priority list, and can go out at the transmitter, leave the STL's alone. The path works, and anything digital just adds complexity. If the STL's are truly ancient, replace one pair of transmitter/receivers at a time. Marti STL-10's are still made by Broadcast Electronics and are available from various broadcast equipment suppliers. Old STL-10 pairs have value if they are working--usually bring around a grand on the used market. Or rebuild one of the old ones for a back-up. Other old models of mono STL's, such as Mosely 505, use difficult to find IC's and are now, for the most part, obsolete.

B. If RDS song/title is something you really want to add, switch to a composite STL. Again, stop up your ears to the siren song of the digital gadgeteers; you don't need the headache of paying a contract engineer to play with these things. With a composite STL, distance to the transmitter becomes an issue. If you are relatively close~ under ten miles with no big obstructions, you should be able to drop a composite in without any problems. Would be advisable if you have someone doing your contract work to give your STL antenna system a good hard look, though. Armstrong and TFT make reasonably priced composite systems. (Remember a change from dual to composite will require modification to the STL license).

2. Once past the RDS question, next is processing. From your post, you say the processing is at the studio. If this is the Orban ST chassis ahead of the dual STL's, fine. If you keep the dual STL's leave it in place, then replace the 8100 with an Omnia One. Just put one in at a classical music station--good sounding box, under $2500. If you have the budget--the next step up is one of the more expensive Omnia or Orban processors--but they come in at new car prices.

A. If you are going with just call and slogan on the RDS, and keeping the dual STL's, the RDS can stay at the transmitter,--it takes the pilot signal from a feed on the back of the Omnia, and the RDS signal is then connected to the "SCA" port of the Omnia. If you install a composite STL, both Omnia and RDS go back to the studio and are hooked up the same way. The composite audio signal out of the Omnia has the RDS signal "piggybacked" onto it, and feeds directly into the composite STL.

B. As mentioned, you can leave the Orban ST chassis in place ahead of the STL's if you keep the dual system. If you have other equalizers, compressors, squeezers of various design in place now, I would pull them all out and just feed the console into the STL. You can duplicate and improve the sound using just the controls in the digital processor. Moving the new processor to the studio and using a composite STL? Just feed your console directly into the processor/stereo geni. Unless you are automated most of the day with widely varying audio levels, there is no need for a lot of extra boxes. The Ariane box is a nice AGC if you have problems with widely varying levels, but it is expensive.

C. As mentioned, if you are using the standard analog feed to the digit, leave it alone.

 

[BobOnTheJob]

A lot of people speak favorably of the Barix Instreamer....and while I've never installed one, I pushed for a compsoite STL system and was over-ruled due to money issues. The Barix "won"...the station "lost". The Barix has butchered the sound of the station to the point that I am ashamed of it and regularly distance myself from it. You can no longer listen to yourself on the air live, nor can two physically separate studios interract live on a broadcast (due to the 1 to 20 second variable delay) and every time there's an ISP issue, you're off the air. For those who are using those things with success, I am genuinely happy for you. But my experience says if you have a working STL, the Barix option is a huge downgrade.

 

[busyradioguy]

A lot of people speak favorably of the Barix Instreamer....and while I've never installed one, I pushed for a compsoite STL system and was over-ruled due to money issues. The Barix "won"...the station "lost". The Barix has butchered the sound of the station to the point that I am ashamed of it and regularly distance myself from it. You can no longer listen to yourself on the air live, nor can two physically separate studios interract live on a broadcast (due to the 1 to 20 second variable delay) and every time there's an ISP issue, you're off the air. For those who are using those things with success, I am genuinely happy for you. But my experience says if you have a working STL, the Barix option is a huge downgrade.

It's finally nice to hear some real world experience of the Barix unit as an STL. I have always believed using any form of IP as an STL system is a bad way to go. I have very little doubt that audio over IP would work great for something like live remotes such as sports coverage, but as Bob noted, there are severe flaws with using it as a full fledged STL.

 

[Chuck]

It's finally nice to hear some real world experience of the Barix unit as an STL. I have always believed using any form of IP as an STL system is a bad way to go. I have very little doubt that audio over IP would work great for something like live remotes such as sports coverage, but as Bob noted, there are severe flaws with using it as a full fledged STL.

I think a lot of this depends on your network connection. Where it works best is with a private point-to-point network. At it's highest quality settings, the audio from the Barix boxes is quite good. Keep in mind that it is compressed, so if you put it in line with several other compression schemes, things can get very weird, very quickly. That is not particularly the fault of the Barix units. It is a simple fact that if you encode and decode several times along the way, your audio will suffer.

If you use these devices over the public Internet, your connection will be no better than your Internet connection. This becomes most noticeable when you must go through a variety of providers. If you can keep everything on one network, life will be much better. That is not something unique to Barix, all systems that use the Internet suffer the same problems.

I’ve been using a pair of these things for over two years and I’m very happy with the results. They are very useful tools if used properly.

 

[busyradioguy]

But there is still the delay factor in your setup. How do your jocks deal with having to listen to the program feed while they are talking live, as opposed to the off air signal?

You're right that all encoding and decoding from any such IP stream will hamper the audio, and that's not just with the Barix boxes. Even TieLine's GSM Codec for Wireless Cell Phones had delay issues from the encoding and decoding.

The only way I can foresee using any sort of Codec in an STL environment, is something with no more than 100 ms in delay, such as the Comrex Matrix to Matrix or even Vector to Matrix, over a POTS line. Short of Microwave or an EQ'd dry pair, the Comrex POTS Codec is as about as real-time as you can get, with minimal delay.

 

[LA_Guy]

I respectfully disagree!

A lot of people speak favorably of the Barix Instreamer....and while I've never installed one, I pushed for a compsoite STL system and was over-ruled due to money issues. The Barix "won"...the station "lost". The Barix has butchered the sound of the station to the point that I am ashamed of it and regularly distance myself from it. You can no longer listen to yourself on the air live, nor can two physically separate studios interract live on a broadcast (due to the 1 to 20 second variable delay) and every time there's an ISP issue, you're off the air. For those who are using those things with success, I am genuinely happy for you. But my experience says if you have a working STL, the Barix option is a huge downgrade.

It's finally nice to hear some real world experience of the Barix unit as an STL. I have always believed using any form of IP as an STL system is a bad way to go. I have very little doubt that audio over IP would work great for something like live remotes such as sports coverage, but as Bob noted, there are severe flaws with using it as a full fledged STL.

If you are having trouble with your Barix units, then please email me at: [email protected] The Instreamer and Exstreamer when used properly and with a good IP connection can be more reliable then an RF STL. Let me explain:

I had a 950 composite STL that shot over the Los Angeles basin. Not only was it unreliable to the point of being useless most hot summer afternoons due to inversions/ducting but it also interfered with STLs on its frequency hundreds of miles away during these times (after all, the signal has to go somewhere).

Yes, the Barix units (and other IP units too!) use lossy coding. BUT I defy you to hear any degradation on ANY FM station at bit rates of 160kbps or higher. At 192 kbps, many 'golden ears' can not hear the difference between MP3 and CD!

If you are having a problem, it's likely due to either a problem with how the Instreamer is set up and/or the quality of your IP connection. Either is fixable and you will be proud of how your station sounds again.

I look forward to hearing from you (or anyone else for that matter)....

PS: Delays in audio are part of life these days. The delay in my cable system (Time Warner) is seven seconds. IBOC also introduces a long delay in both the analog and digital recovered audio.

With a good IP connection, delays in the Barix can be cut down to milliseconds. I have a 160 kbps cross country link where I have a 2 second buffer in the Exstreamer. Total delay: 2.4 seconds. Total delay to Switzerland: 2.6 seconds.

Even satellite (Starguide) and many digital processors introduce enough delay to make off air monitoring impossible. It's what it is today, live with it.

 

[busyradioguy]

First and foremost, "I" can hear a huge difference between say MP3 vs CD / wav.

I don't care that anyone thinks MP3 encoding and decoding is unnoticeable. We used to use MP3's over 250K, on the automation system. That's the first level of encoding / decoding. Add in the digital, M icrowave, composite STL, and there's your second level. By the time that crap hits the radio, the MP3 source material sounded tinny and brittle. When I re-ripped much of our material as .wav files for the automation system, we knocked it down to only one level of encoding and decoding, and that's with the aforementioned digital STL. The difference was like night and day! Our jocks can, and in fact do monitor the off air signal with this setup, when they are on live.

I would only use any IP streaming product to cover a live remote, where all you stream is the voices. Everything else gets played back at the studio. I've studio produced close to 500 sports broadcasts whereby the Comrex Vector to Matrix POTS Codec provided the remote audio, and the off air signal could be monitored by me at the studio, for everything on every single remote we've ever done using the Comrex gear... You could never do this with any IP streaming technology.

For the record, I don't have any IP streaming of any kind from any product, in use. I would only look at that stuff for doing live remotes, such as the sports coverage, and not as an STL.

 

[LA_Guy]

First and foremost, "I" can hear a huge difference between say MP3 vs CD / wav.

I don't care that anyone thinks MP3 encoding and decoding is unnoticeable. We used to use MP3's over 250K, on the automation system. That's the first level of encoding / decoding. Add in the digital, M icrowave, composite STL, and there's your second level. By the time that crap hits the radio, the MP3 source material sounded tinny and brittle. When I re-ripped much of our material as .wav files for the automation system, we knocked it down to only one level of encoding and decoding, and that's with the aforementioned digital STL. The difference was like night and day! Our jocks can, and in fact do monitor the off air signal with this setup, when they are on live.

I would only use any IP streaming product to cover a live remote, where all you stream is the voices. Everything else gets played back at the studio. I've studio produced close to 500 sports broadcasts whereby the Comrex Vector to Matrix POTS Codec provided the remote audio, and the off air signal could be monitored by me at the studio, for everything on every single remote we've ever done using the Comrex gear... You could never do this with any IP streaming technology.

For the record, I don't have any IP streaming of any kind from any product, in use. I would only look at that stuff for doing live remotes, such as the sports coverage, and not as an STL.

I didn't say (nor imply) that you couldn't hear a difference. I said that within the limitations of the FM medium, I defy anyone to hear a quality difference with a 160 kbps or higher MP3. When you talk about build up using but one system, you show your ignorance of lossy coding. YES you can have build up-but ONLY if you use DIFFERENT coding methods
and/or rates. If you start out with a 44.1 kHz 256 kbps MP3 file and maintain THAT coding and bit rate (or better), then you will NOT have any further quality loss-all things being equal. What WILL make a difference are many D/A and A/D conversions-especially with poor quality codecs (like the ones in most consumer computers). Has it also occurred to you that the ANALOG portions of these sound cards could also be causing many of your problems? On my motherboad they use a crappy 4556 opamp after the converter for the reconstruction filter (UGH!). Even my M Audio card is loaded with 5532s-an opamp that I only consider fair for audio today.
At the NAB, we had a stream originating at my computer at home that people could listen to in the booth. It was playing FLAC files that came out of my M Audio Audiophile 196 sound card as coaxial SP/DIF and went right into the Instreamer's coax digital input. At NAB, we used a laptop as a wireless bridge, connected to an Exstreamer with a crossover cable. More then a few people that heard our 160 kbps stream pulled on the headphone wires to make sure they WERE truly connected to the Exstreamer! It's quality was FAR beter then any FM station could possibly sound (including IBOC).

Look, everything is a compromise...but realizing that and doing the best you can with what you have allows you to max things out (as opposed to throwing up your hands and proclaiming something impossibly useless).

But, I'll let you decide for yourselves...I have a 160 kbps stream up at HTTP://76.171.40.49/xstream. Paste it into Winamp and let me know what you think. For those with Exstreamers, try BRTP://76.171.40.49:80.

 

[Sgeirk]

What kind of processing is used in front of the 160kbps stream? Sounds really good!

I still, however, would always prefer never to have my over the air revenue dependent upon a stream via the internet.

Scares me. Really.

 

[Chuck]

What kind of processing is used in front of the 160kbps stream? Sounds really good!

I still, however, would always prefer never to have my over the air revenue dependent upon a stream via the internet.

Scares me. Really.

It really seems to be quite reliable if you set it up correctly. I suppose the choice depends a lot on your market. If I were in New York, LA, Dallas or any other major market, I'd agree with you. I'd also hope that management has the budget to do this really right. Even so, a pair of these things might make a great back-up. It is very cheap insurance. It sure beats silence when lightning strikes that nice new STL system you just installed.

For those of us who are in the outskirts of markets that are measured in triple digits, the paradigm changes. We don't have unlimited budgets. These things are great for connecting two studios together, and even work very well for STL purposes. To some extent, you do get what you pay for, but for well under $1000, you can have a decent sounding and reliable connection. I really haven't discovered anything as easy to use or that's anywhere near as cost effective, unless it happens to be a dry pair that you can use for free. Past that, these devices are an elegant solution.

By the way, the latest edition of Radio Guide has part three of Dana's excellent article about using the Barix boxes. All three episodes are loaded with hints and tricks that make these things work as promised. It is a must read, especially if you are considering adopting this or similar technology.

 

[Sgeirk]

For me, it has nothing to do with whatever market I'm in and just more to do with reliability.

As a backup? Absolutely! To get audio back and forth in a non life threatening situation, okay.

Just because you CAN do something, doesn't mean you should. Not 24/7 on my mains.

 

[CW]

Okay, I am General Manager of a group... so that tells you that I know nothing about radio. That's not necessarily true, but engineering is not my strong suit! However, after 15 years in the business, I did learn a little along the way.

It's 10pm on a Friday and I have a problem that I am curious to find the answer to...

I am using left and right STL's to send my signal from the studio to the txmtr site. Once I get the signal to the txmtr site, I use two STL Receivers and run them into an Orban Optimod 8100 processor. I come out of the Orban Composite (using BNC Connectors) to the Exciter

HERE'S THE QUESTION... The Orban is older than my morning show team's jokes! Is there a better way to combine the two STL signals to composite? Also, I have no idea why the exciter (Harris Digit CD) is running analog but it is? Other information: I would like to run my RDS Generator as well. Should I just shut up my whining and keep using the Orban (which does no processing, all of that is done on the studio side) or is there another way... How much is a multiplexer compiler?

I am sure that I have not given you enough information... but if you can decipher my question, I appreciate any help

B.A. "Sandy" Sanford
Regional Manager
Noalmark Broadcasting Corporation

Ahhh did you know that one of the oldest and most respected (by most) engineers in Dallas is Sandy Sanford???? (Long time member of SBE Chapter 67)........thought you might want to know

As for the Digit, what module is on the Digit? The AES or is there a L/R analog module?? The way you have the layout now, I would need to know the STL gear before recommending a change...
BUT having the processor feeding the composite into the Digit is the better way to go performance wise (KLUV in Dallas is doing this!) I never did like the AES input vs the composite...IF you had a STL that can go composite in and out, you COULD move the Orban to the studio.....DONT count out the 8100......it is STILL a great processor; add the XT chassis if you want to improve it but an external graphic EQ and heavier AGC would work.....but the plain 8100 is still highly valued! I dont know WHAT processing you have at the studio BUT I would get a XT chassis, put a Compellor or simple levelor/AGC at the studios to the STLs (just to prevent overshoot) and let the 8100 with the XT chassis do the processing at the xmtr! You will get a better sound in my opinion (and my former Dallas stations had 8100s as backup! To me they sounded better than the 8200s the mains ran)..

If you move the 8100 to the studio and run composite all the way to the xmtr, you can inject RDS into the 8100; otherwise, save cash and look at the Omnia 1 processor.......

 

[CW]

Sandy I can probably help with the RDS side - that's what I do for a livin'. PM me or just ask away right here.

Paul E. Burt, VP Broadcast Operations
AlertFM / GSS, an RDS-based alerting company

Paul!
Did I hear you are in Baton Rouge now or still in Miss???
(your fellow ex CC employee

 

[Doctor_Technical]

Hey CW, sent you a PM. Paul