LPFM Audio Processsing

[BostonRadioDJ]

Folks..

I have a question that perhaps someone more talented in the technical aspects of processing can help me with. I won't go into my background, but suffice to say I've 'Been Around' commercial radio, in various size markets for over 30 years, in various positions including On Air, Production, Management, and Engineering. I am not 'out of the business' so to speak and run my own company. Anyway..further to the point

Where I live, there is a LEGAL 100W LPFM. All automated of course. There are also several class B fm's in this market (how profitable, who knows?)...here is the deal...I know the owner/operator of the LPFM. Lets just say that he has 'Less than quality' Tx'er, Antenna, Feedline, etc.....BUT..the audio processing of this tinker toy set up is absolutly amazing!! Easily blows away all the commercial stations in terms of audio quality....and I mean with ALL program material aired. I have studiied this for the last year at least.

My question is..would anyone care to take a stab at what he is running for processing gear? I don't know..and he keeps it pretty close to the vest.

Put another way, taking into account the 'quality' of the gear (and known 'cheapness' of the owner...what the hell can sound so good...consistantly?

Any Thoughts??

Than
T

 

[GeneSavage]

My first guess would be Breakaway Broadcast: http://claessonedwards.com/

 

[Chuck]

My next guess is a BW Broadcast DSP-X Mini. A lot of bang for the buck.

 

[Studio1]

My immediate guess is Breakaway as well. As much as I don't like software processing, this system absolutely kicks the donkey's behind and rivals ANY of the commercial processing.
There is a LPFM here which uses it and when listening, it is impossible to distinguish it from any of the high power commercial stations in the area.

 

[GeneSavage]

The other thing I've noticed about Breakaway is that you can set it for blowtorch and it won't distort. It keeps the levels smashed up at 100% all the time... but that's what you'd expect if you set the controls at 100%.

When you mentioned loudness, that was what I immediately thought of. It can be made stupid-loud, if that's what you want. The (clean) density is frightening.

I've never worked or (knowingly) heard the DSP-X, so I can't comment on it.

If he would install a $1,500 piece of equipment... wouldn't an Omnia One go for about that? I've heard rave reviews for the One...

 

[RadioMan203]

My guess is if it's more quality than loud/grudge perhaps he picked up a used Optimod 8000a. I was looking for one for my student FM station as I hear one on a peanut whistle that sounded fabulous.

 

[Groove1670]

My immediate guess is Breakaway as well. As much as I don't like software processing, this system absolutely kicks the donkey's behind and rivals ANY of the commercial processing.

Anyone on the board using this software on their commercial FM station.

Also which soundcards have a Composite out ?

 

[river radio ranch]

A possibility also is the next generation Hnat Hindes Broadcast Technology UM2000 processor.
If it's not a loudness war, they sure sound nice and clean...
Again, of course, garbage in garbage, but assuming correct levels,
I'd put it up against a good condition 8000A..

 

[TomT]

1. An 8100 with good quality audio going into it.
2. An Omnia--a one, or even the old boxes, a 3T or the 1990's "Classic" Omnia 4 band

 

[Kmagrill]

Also which soundcards have a Composite out ?

Much of this has been discussed here many times including recently at:

http://boards.radio-info.com/smf/index.php?topic=202365.0

If you are thinking of finding a sound card with a BNC composite output, forget it. On the other hand, cards with 192kHz sample rates can produce composite audio on their standard line outputs.

Any waveform, including composite audio, can be reproduced by a sound card with a high enough sample rate. In the case of composite audio, the highest frequency is 53kHz, so the sample rate has to be at least 2x 53kHz in order to reproduce a composite output. Since most sound cards are sampled and 48kHz, 96kHz or 192kHz, the only commonly found card capable of reproducing composite is a sound card with a 192kHz sample rate. Producing the composite waveform (including pre-emphasis, 15kHz filtering, 19kHz pilot, and 38kHz sidebands) is just done in the software and the resulting wide-band waveform is sent to the sound card's output. This is not all that different than the way digital stereo generators have worked since the 1980s, except it's done in software rather than hardware. Theoretically, any sound card with a 192kHz sample rate can be used as a composite audio source, including the $25 variety. In practice, some cards are better than others, and will produce less distortion, fewer overshoots, etc. Also, for solid peak limiting performance, the amplifiers need to be dc coupled. If you have a 192kHz sound card, there are several sources for stereo encoder software online, including some free ones, that you can use to create composite audio suitable for driving an exciter's composite input.

On the budget hardware side of the equasion, I put together a super low budget LPFM chain for a guy in 2007 consisting of a nicely refurbished Optimod 8000, driven by a pair of Audio Prism IIs with a graphic EQ driving the whole thing. It sounds absolutely amazing. I mean to say that it is as loud as the digital stuff and it has a very consistent sound with rich bass and open highs. Frankly, I didn't expect it to all work together so well. The owner loves it and I've had some local folks acuse me of pulling their legs when I tell them what is being used - until I show them a picture. The Optimod is the key to the loudness with light-handedly set prisms and eq providing dynamic frequency stabilization. The whole setup came from eBay at a cost of about $900.

 

[Ultanium]

Bet you a dollar its Breakaway. Wanna see how cheap the owner really is? See if the processing is off a bit when they go live, meaning they bought the $30 version instead of the more expensive live version. I run the $30 flavor, and it sounds like the big boys.

 

[techie2]

The LPFM that I am involved at started out with an Optimod 8000 but it never sounded good on the air. It always sounded weak and thin compared to anything else in the market except maybe the classical station which runs light processing on purpose. I didn't work on it much to see if it could be improved on at all by using other boxes in front of it, as the 8000 was replaced by an Omnia 3T that is at least competitive with what is on the air in the area. The 8000 is still around for backup duty but it's definitely a step backward for us when it's on the air.

Just lit up a new CP with a better antenna, an ERI 100A, but it would be nice to actually run a decent transmitter. Other than the Nautel VS300, are there any other transmitter options out there that are LPFM certified besides Nicom and Ptek level equipment?

 

[Tom Wells]

If an owner/operator/engineer also has golden ears, they can make a lot out of very little investment.
That said, I was not suitably impressed with my best efforts until mutliband processing on PC was introduced in Breakaway
Broadcast. I have not recently gushed my boundless appreciation for the product.
Consider this as sane but boundless gushing:
As an rf engineer who stayed out of the whole biz (yet have always breathed rf) I must radio in AM, and as a
part 15 op, the only thing I have to excell in is audio, so that's where I've focused.
No end was spared in the design to achieve the highest linearity and well-digested and balanced tapes could be made to
sound very good, but live sources suffered badly for want of multi-band action.

When I added Breakaway Broadcast to the AM, there was some learning curve, but the result is a
wall-o-sound-voice-o-God huge (with plate reverb) riducluous depth and strength and breadth of sound in a 150% signal.
It's so fun to play with when the sound wall is impossibly huge in headphones, even in mono rf airchecks.

You should see the how enevlope throbs and opens up on a scope.
It doesn't just lay there after BBP, it's pretty much like stripping away 5 layers of dub/mastering/etc and
having the musicians in studio with the best engineer on the planet.

Oh, yeah, on old single speaker AM car radio dashboard speakers, you can see images of the performers standing on the dash!

Those who ever heard CKLW, WLS, WABC, etc in the 1960s on a properly huge radio of the day or car
radio dashboard speakers understand the sound I refer to.
It's a shivers-for-music-on-AM thing that you either get or you don't.

Even at remote distance, and second hand reference, I'd say it's probably Breakaway.

 

[Kmagrill]

Other than the Nautel VS300, are there any other transmitter options out there that are LPFM certified besides Nicom and Ptek level equipment?

There are lots of transmitter choices out there, but as you have already mentioned, LPFM owners need to be certain that their equipment is FCC type certified. An owner in Florida got an NAL for $12,000 recently, of which $7,000 was for operating a non-certified transmitter. The offending transmitter was not a toy. It was a genuine, albeit malfunctioning, broadcast exciter that pre-dated the LPFM certification requirement. Full service broadcasters and even translators have no certification requirement, so buying name brand gear does not guarantee compliance with the law. Be sure to ask, first. Type notified or type verified equipment is not legal for LPFM service, though it may be legal to have such gear as backup to a certified main transmitter.

One FCC Certified brand not already mentioned is Broadcast Warehouse. My personal experience would suggest that they are not yet in the Nautel class. One of the LPFM stations here has one and it gives trouble about once per year. So far, the crystal in the stereo generator stopped oscillating (no audio passes), one half of the BLF278 final failed open without cause at 9am on a clear, cool spring morning (No rf output even if the other half of the final is okay) and finally, the main fan quit (rf output reduced to 70W while the unit was nearly too hot to touch). At least the thermal protection saved the amplifier on that occasion.

I have to say that my operational experiences with Nicom have been good. The transmitters aren't fancy but I've had no failures. So far, we have 30W and 250W units in the field. The oldest is about 4 years.

Ramsey also makes a 50 Watt LPFM certified transmitter.

Crown's transmitters are quite rugged and, I believe, are LPFM certified.

 

[WNTIRadio]

Have some Nicoms on translators and haven't had any problems with them. One has been running for 5 years. If they're the slim units, just be sure to check the fans on them every month when you visit the transmitter site. They sound decent too, using the internal "clipping" and feeding it audio from the main station, they sound better than the horrible idea of "audio processing" that is in the Crown units at a couple of other stations. Probably because all it does is clip any spurious peaks, while the Crown is trying to "process" the audio.

Have had a couple of Crown units have some cooling issues, but again, check your fans regularly! Can't speak for the LP Nautel stuff, but I would imagine it's just as good as the full power transmitters I've encountered.

 

[Chuck]

I've had a Nicom in service for almost 10 years. Over that time I've had to replace two fans but nothing more. It surely doesn't owe me anything and sounds quite decent. Audio for this one comes from a DSPX-Mini, which is largely responsible for the signature sound, but the good news is the Nicom passses it with no problem.

 

[DudeFan]

Bext is another choice. Make sure the model you order is certified. Most of the 30, 100. 150 and 300 watt units are. Knock on wood, we've gotten trouble free service from our Bext.

 

[pqgeorge]

Bext is another choice. Make sure the model you order is certified. Most of the 30, 100. 150 and 300 watt units are. Knock on wood, we've gotten trouble free service from our Bext.

For transmitters, PTEK's are great units that won't break the bank. All of my FM's that I engineer have PTEK's. They come with an on board Stereo generator at no extra cost. Check them out! For processing, my non-comm, (WXRB-FM) uses an Optimod 8100A driven by an Aphex Compellor. Sure, it's old school technology. But, for a 14 watt signal, we sound nice!

 

[RealityCheckr]

I hate to be a stick in the mud, but my first guess would be is that the station is exceeding 100% mod. This may not be intentional, but due to a lack of monitor.

Anyway, unless you eliminate this possibility, it would be hard to make judgements.

 

[Chuck]

For transmitters, PTEK's are great units that won't break the bank. All of my FM's that I engineer have PTEK's. They come with an on board Stereo generator at no extra cost. Check them out! For processing, my non-comm, (WXRB-FM) uses an Optimod 8100A driven by an Aphex Compellor. Sure, it's old school technology. But, for a 14 watt signal, we sound nice!

After almost 9 years in LPFM I ended up with a full power commercial station. When I got it, the station had a Crown exciter running a QEI transmitter. I have retired that rig in favor of a P-TEK Gamma transmitter. I was quite surprised by the improvement in audio quality. I don't know if the Crown exciter was the source of the "gritty" sound I'd heard, or if it might have been something else in the QEI. In any case, the station sounded dramatically better after the change-over.