Excellent SDS sound thru compressor

[jeffdafoe]

I found this discussed before with regards to streaming, but if you're using the SDS100 at home with an amplified speaker, you can get fantastic audio levelling if you add a compressor. I have a small home recording studio and I had an FMR Really Nice Compressor (RNC) sitting unused on a shelf. The RNC settings are theshhold at minimum, ratio 4:1, everything else at noon and "super nice" on. The SDS100 is at vol 10. The audio is smooth as butter no matter how quiet or loud the talker is.

I do run with the scanner plugged into the USB port on my PC and this did cause noise under the setup above. I used a isolation transformer (ART Clean Box II) after the compressor and it went away completely.

 

[phask]

I found this discussed before with regards to streaming, but if you're using the SDS100 at home with an amplified speaker, you can get fantastic audio levelling if you add a compressor. I have a small home recording studio and I had an FMR Really Nice Compressor (RNC) sitting unused on a shelf. The RNC settings are theshhold at minimum, ratio 4:1, everything else at noon and "super nice" on. The SDS100 is at vol 10. The audio is smooth as butter no matter how quiet or loud the talker is.

I do run with the scanner plugged into the USB port on my PC and this did cause noise under the setup above. I used a isolation transformer (ART Clean Box II) after the compressor and it went away completely.

Good idea - are these just one input? I have plans to re-do the shack next year, probably settle for 3 radios - 3 speakers. Be nice to have balanced audio.

 

[jeffdafoe]

Good idea - are these just one input? I have plans to re-do the shack next year, probably settle for 3 radios - 3 speakers. Be nice to have balanced audio.

The FMR RNC is stereo ganged so it can't be driven dual mono. There's other compressors that are dual mono, when I go for inexpensive equipment I like DBX. Coincidentally, the other thread I saw about someone using a compressor for stream levelling was using a DBX 166 which is dual mono. I'm sure any compressor would work, just set the threshold really low. That causes it to get driven well into its curve, giving it a fast response to louder signals, which is what we want for this application.

If your budget is on the upper end, a 500 series rack (typically more like the size of a carpenter's toolbox) and 3 compressor cards would be slick. The 500 series has become insanely popular over the last decade, with dozens and dozens of rack vendors offering racks of varying prices and slot counts (500 Series Gear Buying Guide | Sweetwater). The 500 series racks are all usable with any 500 series cards. There's a gazillion 500 series compressors. DBX's classic there would be the 560A. If you wanted to drop the cost you could look on ebay for the Alctron brand, they make both the racks and various cards including a compressor. If you wanted to get even more carried away, you could get a rack with enough slots to support 3 compressors and 3 EQ cards. On some racks you don't even have to jumper, the rack has a switch to enable the passing of a card's output to an adjacents card's input. With the compressor and EQ combo, you could exactly tailor the sound to your liking. The really important thing here is, all together, this setup saves your hearing.

-Jeff

 

[Ubbe]

You can get a Behringer MDX2600 for 2 channels or a MDX4600 4 channel but with less controls but are probably ok at $120 and a small $100 mixer like a Xenyx QX1002 are always useful as you could mix different sources down to 2 channels for the MDX2600 and can instantly mute all or select only one source to listen to very easily.

/Ubbe

 

[AKJohnny]

I found this discussed before with regards to streaming, but if you're using the SDS100 at home with an amplified speaker, you can get fantastic audio levelling if you add a compressor. I have a small home recording studio and I had an FMR Really Nice Compressor (RNC) sitting unused on a shelf. The RNC settings are theshhold at minimum, ratio 4:1, everything else at noon and "super nice" on. The SDS100 is at vol 10. The audio is smooth as butter no matter how quiet or loud the talker is.

I do run with the scanner plugged into the USB port on my PC and this did cause noise under the setup above. I used a isolation transformer (ART Clean Box II) after the compressor and it went away completely.

Nice, thanks. Can you tell me what audio cables you're using for in & out of the compressor? Thanks.

 

[flythunderbird]

There's other compressors that are dual mono, when I go for inexpensive equipment I like DBX. Coincidentally, the other thread I saw about someone using a compressor for stream levelling was using a DBX 166 which is dual mono.

I like dbx compressors, too. My two feeds run through a dbx 166xs, which is switchable between dual mono and stereo ... it does a terrific job!

 

[jeffdafoe]

Nice, thanks. Can you tell me what audio cables you're using for in & out of the compressor? Thanks.

From the radio's headphone jack to the compressor's input I'm using a 3.5mm (1/8") stereo (TRS) to dual 1/4" mono (TS). You could probably also use a 3.5mm (1/8") mono (TS) to 1/4" mono (TS) which would make more sense, I just didn't have one handy. From the compressor to the isolation transformer I'm using 1/4" mono (TS) to 1/4" mono (TS) (a 1/4" mono jumper cable). The output from the isolation transformer is 1/4" mono. This is all unbalanced. To do it balanced you'd need 1/4" stereo (TRS) from the compressor onward and you'd need an isolation transformer that supports balanced connections. I'd try it without an isolation transformer first to see if you even have a ground loop problem, I only have it on the SDS100 because I have it plugged into a computer's USB port.

-Jeff

 

[UPMan]

If you plug a 3.5mm mono into the scanner, you'll short out half the audio amp...and likely would not be as pleased with the audio results.

 

[jeffdafoe]

If you plug a 3.5mm mono into the scanner, you'll short out half the audio amp...and likely would not be as pleased with the audio results.

Yeah lets not do that then, I'm going to edit the post. Or not, looks like there's an edit time window.

-Jeff

 

[jeffdafoe]

If you plug a 3.5mm mono into the scanner, you'll short out half the audio amp...and likely would not be as pleased with the audio results.

What are your thoughts on leaving one side open (stereo to dual mono, only one side of dual mono connected)? In my config I have both plugged in but I only use one output on the compressor. For what these guys want to do it'd be ideal to only connect to one input channel.

-Jeff

 

[jeffdafoe]

(deleted)

 

[Ubbe]

Both the compressor/limiter and the mixer has balanced ground loop isolation inputs and outputs that's perfect for use with scanners. You have to use the correct cables though. If an audio device only have grounded inputs-outputs you easily get into ground loop problems with hum and it's not a device that's inteded for serious work and you should stay away from it.

/Ubbe

 

[jeffdafoe]

The sds100 is unbalanced.

 

[Ubbe]

Yes, but you connect that unbalanced audio to a balanced input, using the correct cable, of a compressor or mixer to get rid of the ground loop problem that more often than not will give mains hum in the audio. As long as one end of an audio cable are balanced and free from ground you have a minimal risk of getting any sort of audio quality problem.

/Ubbe

 

[RFI-EMI-GUY]

I will have to try this with my 536. I was straining to hear a low talker yesterday.

 

[jeffdafoe]

Yes, but you connect that unbalanced audio to a balanced input, using the correct cable, of a compressor or mixer to get rid of the ground loop problem that more often than not will give mains hum in the audio. As long as one end of an audio cable are balanced and free from ground you have a minimal risk of getting any sort of audio quality problem.

It's not ground loop hum, it's some sort of digital interference coming from the USB connection somehow. I was using a balanced connection at first and it didn't eliminate it, that's why I grabbed the isolation box. I was getting a sound like a DC pop every few seconds but not at an even interval. I didn't drag the scope out to do much analysis.