Does anyone use Aphex Compellor?

[Jay Walker]

Now I remember what the problem I had with the CRL units was, among many.

The only place I ever ran CRL was on AM radio. On FM the high end was WAY TOO DIRTY. The primary reason I ran them then was the Orban was not out yet and CRL did give you good asymmetrical positive peak control. You could make a Continental Power Rock stand up on it's back legs at 125 positive and not blow by 100 negative.

CRL was OK for the times on most PDM/PCM transmitters but pretty hard on Plate Modulated modulation transformers unless you had excess iron and a hefty plate supply when running heavy asymmetrical modulation

 

[Studio1]

A 320 however can be modified fairly easy...

Could you please detail the mod for the 320? I have one or two of these and if they can be made better, I'm all ears.

Cut circuit at pin 1 of U101 and replace it with a 0.047µF capacitor. You need to do this on both L & R boards.
You won't turn it into a real 320A with this, but it does make a big difference.

Thanks for that. Maybe not equal to a 320A but if it makes it better, it's got to be good.

 

[TedAlexander]

On WKNR 850AM in Cleveland, we use an Aphex Compellor at the studio to smooth out the board ops "adjustments", and an Omnia ONE AM at the transmitter. Tune in if you are within range. Daytime range is quite good with the 50kw.

Ted Alexander W8IXY

 

[satech]

Yes "Killing Me Softly" is a great test song. I can't wait to see how the Compellor does on that track.

Try "The Power of Good-bye" by Madonna. The very strong deep bass that comes in during the first vocal line will cause very obvious and annoying "bass pullback" on any wideband AGC.

 

[BobOnTheJob]

On WKNR 850AM in Cleveland, we use an Aphex Compellor at the studio to smooth out the board ops "adjustments", and an Omnia ONE AM at the transmitter. Tune in if you are within range. Daytime range is quite good with the 50kw.

Ted Alexander W8IXY

Ted...just an FYI that with a 400' longwire and a Drake R8, WKNR 850 is here all day just 80 miles north of 840 WHAS. It's not strong but it's there 268 air miles from the center of Cleveland. WTAM 1100 is a 7 on the S meter and WKNR is just above an 8.

 

[satech]

Listened to it... I can hear it flattening out transients on the snare hits. Now I remember what the problem I had with the CRL units was, among many.

If you could slow down the attack time it would help out. The Compellors have other drawbacks, but they don't squash the transients when set up properly.

As the video description says, that was with the gain reduction maxed out and the attack/release time set to fast. If you max out a Compellor, you can definitely hear it crunching away at the peaks even moreso!

I've found that with a Compellor, I have to keep the Process Balance control most of the way towards Levelling (around 9 o'clock) in order to prevent it from doing an unnecessarily high amount of compression on most program material.

CRL was OK for the times on most PDM/PCM transmitters but pretty hard on Plate Modulated modulation transformers unless you had excess iron and a hefty plate supply when running heavy asymmetrical modulation

CRL's AM processors have an internal jumper option to pass the bass peaks directly through to the final clipper, which of course turns kick drum beats into big fat square waves! I believe Orban had a "disco" modification for the Optimod-AM 9000 to do the same, and it was well-known for burning out modulation transformers!

 

[WNTIRadio]

I never run a Compellor in any on-air situation above 9 o'clock on the process balance control. That's what I meant by "set up properly". That CRL isn't flattening the bass, it's flattening around 600Hz to 1.5kHz... the snare hits are more like a "thunk" on a cardboard box than a tight snare drum.

The CRL self noise was always an issue to me. They weren't very quiet units, any of the 800 series (or 400 series) and always had a bit of grunge on them no matter what. I also didn't like that the audio was on those adjustment pots, made for some noisy tweaks until they got sprayed out. Didn't like them on FM at all.

 

[RadioMan203]

@WNTIRadio: The AM I engineered has the older CRL stereo processing for AM and when adjusted for anything other than gentle it seemed to have a gritty sound. I was never very happy with them.

One of the units developed an intermittent that would go away when you tapped the unit (or the rack). I ended up getting a newer version of the system on demo so I could pull the offender out of the rack and repair it. To my surprise, the newer stuff didn't sound much (if any) better than what we had! At one point I ended up subbing out most of the system with an Optimod 8000a feeding the composite STL that was demodulated and fed into the CRL final limiter.

I've rarely heard a Compellor sound bad but in most cases I would attribute it to what was following it. I'll have to try that 9 o'clock setting to see how things run.

 

[satech]

50,000-watt 900 CHML uses CRL processing, with the NRSC filter disabled! 8)

http://www.youtube.com/watch?v=O15zCXo2D-U

 

[317C50KW]

Jay had mentioned he uses a Compellor on the stadium end of his pro football broadcasts. I pulled mine from the shelf and had it on a high school playoff game Friday night, feeding a Comrex Access. I was pleased but we were in a big stadium with a small crowd and using the house crowd mic. I pushed process balance control to about 11 o'clock and finally started hearing that magical mix of crowd noise coming up when the announcer stopped talking in the headsets. I'm going to try the mod and also look at some of the caps...I bought the unit used and apparently C-SPAN was a previous owner. The manufacture date on the sticker was 1993 so tt's probably ready for an overhaul!

 

[fmcentral371]

Ok so let me ask this from all you Compellor 320 owners:

Let's say you keep the process balance at 7 o'clock (i.e. all the way on LEVEL), and you turn it on FAST, does it make the audio "thin"? I understand what a compressor does and the differences between fast and slow rate compression BUT what happens differently when it's only leveling between fast and slow rate?

Thanks.