Re: [Repeater-Builder] An advocate for a little audio compression
On Aug 9, 2009, at 9:07 PM, skipp025 wrote: re: An advocate for a little audio compression. Yeah, I know a decent number of you are in-stone same-in to same-out repeater audio levels types. However, I've changed my opinion. You're a brave man to say it, Skipp. Here's my problem with it. Let's just say there's a very large linked repeater system that decided MANY years ago that they could fix the incoming audio from their IRLP link from BADLY CONFIGURED IRLP NODES by adding a commercial compressor-limiter in-line. I won't say who or where, since I like the folks running it and have ZERO beefs with them. I just need to use them as an example of where compression/limiting is BAD NEWS. However, let's also just say that I've called them from MULTIPLE IRLP nodes I've set up PERFECTLY with a service monitor and swept for audio response, and they ALWAYS complain about whatever it is they're hearing on their end -- after their compressor-limiter. Hey guess what folks. The audio left here JUST FINE... someone on that end decided to muck around with it. Not much I can do about that. What does this phenomenon actually lead to? I don't know. Maybe an idea below... I know my nodes are done right, and I know they have a LOT of other nodes connected to them that sound like ass so they tried to fix it. But, instead of asking those folks to fix their nodes, they tried a fix on their end, and broke things for those of us sending proper levels and audio. If they'd put in a way to TURN IT OFF, they'd hear what a properly set up IRLP node is supposed to sound like. Do I care? Not really. But the experience of that problem over the years, has just entrenched me further in the what comes in is what goes out camp. Do I realize that the vast majority of folks setting up IRLP nodes don't bother setting levels CORRECTLY to a network standard? Oh heck, yes. I rant about that at least once a year on the IRLP list... to mostly deaf ears. So I say, sure... compress away on a local repeater only. But please keep the compressed audio the hell away from outbound links to others... and away from the incoming link audio too. And always provide a way for the USERS to turn it off, just to see if it's having a bad effect. Seems reasonable, doesn't it? I think that's a fair opinion to all. Compress the snot out of local traffic if you want... but please send the rest of us something that sounds like what your users put in out any links, especially IP-based ones. Otherwise you run the risk of really bugging those of us who DID set levels and test audio, by creating a new problem the users on the far end think is OUR problem. What do you think Skipp? Is that a fair point to make? Links to other people's systems shouldn't include compression. Now... the reality is... some repeaters do it anyway... hard to stop it from going out. I can almost always tell ya when someone's on a MODERN (not MICOR) Motorola repeater by listening to their audio coming out of my IRLP node(s). In fact, with the audio set up correctly on an IRLP node, it's downright easy to tell there's a Bat- Wing somewhere on the other end of the link. -- Nate Duehr, WY0X n...@natetech.com
RE: [Repeater-Builder] An advocate for a little audio compression
It's funny- on the most-used local 2m repeater, we don't have a problem with the majority of users, whose voice levels are fine. I think compression is necessary to cut back on a few users who 1) practically shout into the mike, or 2) have bumped up the deviation on their radios because they think that more deviation is better, or 3) are using a multiband radio with modulation still set as for HF, and don't realize that their excessive deviation is causing distortion in the repeater. In any case, it's a few users who are too loud, rather than a few users who are too soft. As a road-show sound engineer and recording-studio operator in an earlier life, I know the benefits of seamless compression. The primary rule is that the static level should have no gain or compression at all, so that the compression begins only when audio exceeds a certain level. An audio compressor is misapplied if it always brings up the noise level between words. My primary audio treatment device was a DBX 166, which also has a noise gate. The trick to using a noise gate properly is to set it so that it opens at the beginning of the first syllable. I spent a lot of time getting the levels and timing fine-tuned so that the compression and gating were undetectable. It can be done with quality equipment, but good audio processing equipment is not cheap. I have found that it is helpful to simply advise a user that he is too loud and needs to back away from the mike, or that he is barely audible and needs to speak up! 73, Eric Lemmon WB6FLY -Original Message- From: Repeater-Builder@yahoogroups.com [mailto:repeater-buil...@yahoogroups.com] On Behalf Of Paul Plack Sent: Sunday, August 09, 2009 10:10 PM To: Repeater-Builder@yahoogroups.com Subject: Re: [Repeater-Builder] An advocate for a little audio compression Skipp, I generally agree, but it's not the fault of the user's voice. It's a lack of training in mic technique, sometimes combined with audio circuits that aren't easily user-accessible. Compression on the repeater eliminate's the user's need to get things right at the source, and one day, he's going to need to operate simplex. I've worked with broadcast compressors for many years, and agree they could play a useful role in repeater audio chains. But I always wanted to design one that was a little different, and digital control of an analog signal path seems like a good candidate. Specifically, I'd like to have something like a compressor with very fast attack and infinitely long release, immediately dropping gain as needed to accommodate voice peaks, but not releasing until COS dropped. This would essentially set the audio gain individually for each user at the start of a transmission, without any ongoing compression to create the obnoxious pumping artifact we all know and hate. The downsides would be additional background noise before the first syllable, and difficulty in distinguishing users with low audio from users with inadequate signal strength. Both would feature increased background noise as a symptom. Then again, IRLP users hand out S-meter reports from a thousand miles away, so maybe it doesn't matter...(sigh) Just running the audio gain 6-10 dB hotter into a fast limiter still allows great disparity in perceived loudness, but at least the guys with low audio can be heard. 73, Paul, AE4KR - Original Message - From: skipp025 mailto:skipp...@yahoo.com To: Repeater-Builder@yahoogroups.com mailto:Repeater-Builder@yahoogroups.com Sent: Sunday, August 09, 2009 9:07 PM Subject: [Repeater-Builder] An advocate for a little audio compression ...a number of operators don't seem to have voices that drive their radios with adequate audio...Consider 6 to 10dB of audio compression in your repeater system... . http://geo.yahoo.com/serv?s=97359714/grpId=104168/grpspId=1705063108/msgId= 93195/stime=1249873641/nc1=4025373/nc2=5689702/nc3=5807838
[Repeater-Builder] An advocate for a little audio compression
re: An advocate for a little audio compression. Yeah, I know a decent number of you are in-stone same-in to same-out repeater audio levels types. However, I've changed my opinion. A number of operators don't seem to have voices that drive their radios with adequate audio and I always seem to be reaching for the volume control. So I've started adding a modest amount of audio compression to a few repeaters and the difference is a very pleasant and well received change. Consider 6 to 10dB of audio compression in your repeater system if you're constantly reaching for the volume control while listening to more than one person talk at different levels. I'm experimenting with higher and even dynamic audio compression values but for most situations the above values seem to work well. If you're not sure how to add a bit of audio compression to your specific system... wouldn't be hard to describe it as in most cases the hardware is already in place. Transparent or flat through repeater audio can be made louder without causing the world to come to screeching halt. cheers, skipp
Re: [Repeater-Builder] An advocate for a little audio compression
what equipment have you used to do the compression? -- Original Message -- Received: Sun, 09 Aug 2009 08:07:45 PM PDT From: skipp025 skipp...@yahoo.com To: Repeater-Builder@yahoogroups.com Subject: [Repeater-Builder] An advocate for a little audio compression re: An advocate for a little audio compression. Yeah, I know a decent number of you are in-stone same-in to same-out repeater audio levels types. However, I've changed my opinion. A number of operators don't seem to have voices that drive their radios with adequate audio and I always seem to be reaching for the volume control. So I've started adding a modest amount of audio compression to a few repeaters and the difference is a very pleasant and well received change. Consider 6 to 10dB of audio compression in your repeater system if you're constantly reaching for the volume control while listening to more than one person talk at different levels. I'm experimenting with higher and even dynamic audio compression values but for most situations the above values seem to work well. If you're not sure how to add a bit of audio compression to your specific system... wouldn't be hard to describe it as in most cases the hardware is already in place. Transparent or flat through repeater audio can be made louder without causing the world to come to screeching halt. cheers, skipp
Re: [Repeater-Builder] An advocate for a little audio compression
I use a Behringer MDX2200. I think it has been discontinued for some time. It has all the hot stuff you want. Compressor, limiter, and a noise gate. It doesn't take very long to tune it in. If you don't have it right, you'll know it... Looks like they are going for about $75 on eSlay. John At 11:10 PM 8/9/2009, you wrote: what equipment have you used to do the compression? -- Original Message -- Received: Sun, 09 Aug 2009 08:07:45 PM PDT From: skipp025 skipp...@yahoo.com To: Repeater-Builder@yahoogroups.com Subject: [Repeater-Builder] An advocate for a little audio compression re: An advocate for a little audio compression. Yeah, I know a decent number of you are in-stone same-in to same-out repeater audio levels types. However, I've changed my opinion. A number of operators don't seem to have voices that drive their radios with adequate audio and I always seem to be reaching for the volume control. So I've started adding a modest amount of audio compression to a few repeaters and the difference is a very pleasant and well received change. Consider 6 to 10dB of audio compression in your repeater system if you're constantly reaching for the volume control while listening to more than one person talk at different levels. I'm experimenting with higher and even dynamic audio compression values but for most situations the above values seem to work well. If you're not sure how to add a bit of audio compression to your specific system... wouldn't be hard to describe it as in most cases the hardware is already in place. Transparent or flat through repeater audio can be made louder without causing the world to come to screeching halt. cheers, skipp Yahoo! Groups Links
Re: [Repeater-Builder] An advocate for a little audio compression
Skipp, I generally agree, but it's not the fault of the user's voice. It's a lack of training in mic technique, sometimes combined with audio circuits that aren't easily user-accessible. Compression on the repeater eliminate's the user's need to get things right at the source, and one day, he's going to need to operate simplex. I've worked with broadcast compressors for many years, and agree they could play a useful role in repeater audio chains. But I always wanted to design one that was a little different, and digital control of an analog signal path seems like a good candidate. Specifically, I'd like to have something like a compressor with very fast attack and infinitely long release, immediately dropping gain as needed to accommodate voice peaks, but not releasing until COS dropped. This would essentially set the audio gain individually for each user at the start of a transmission, without any ongoing compression to create the obnoxious pumping artifact we all know and hate. The downsides would be additional background noise before the first syllable, and difficulty in distinguishing users with low audio from users with inadequate signal strength. Both would feature increased background noise as a symptom. Then again, IRLP users hand out S-meter reports from a thousand miles away, so maybe it doesn't matter...(sigh) Just running the audio gain 6-10 dB hotter into a fast limiter still allows great disparity in perceived loudness, but at least the guys with low audio can be heard. 73, Paul, AE4KR - Original Message - From: skipp025 To: Repeater-Builder@yahoogroups.com Sent: Sunday, August 09, 2009 9:07 PM Subject: [Repeater-Builder] An advocate for a little audio compression ...a number of operators don't seem to have voices that drive their radios with adequate audio...Consider 6 to 10dB of audio compression in your repeater system... .
