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#1
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Dealing with the TV Audio Signal Path
I'm doing a live Messiah recording for a new, major client, and was also asked, "by
the way, can you live-feed the tv people?" Well, yeah, a monitor mix from a toy console under adverse conditions... The local tv production folks assure me they "don't do anything" to the audio, but who knows what "auto" settings are switched in on their gear and worse, what happens when it leaves their hands and heads into the cable system. Shudder. I am running a KM183 pair (with diffraction spheres) in AB stereo with 50 cm separation. This is a departure from my usual MS config, but given that I can't perfectly check the mechanical & electrical alignment "live" this should work well. (In various tests here, and with a friendly competiter's D183s, I've been pleased how this sounds -- mis-aligned MS, on the other hand, can be awful.) Also running two solos, four spots in a rather large orchestra, and two choir outriggers. The main pair should do most of the work, perhaps all -- depends on how the room shapes up when it's full of people. But here's the quest for wisdom... Should I pre-compress my feed to the TV folks in the hopes that AGCs and other downstream manglers will be less inclined to trip? All I have is a DBX 1066 that I've not yet modified. It's fairly clean (more so than the RNC I used to have), but it's still a bit of a polluter. Or, should I just get as uber-hi-fi as possible (such as schlepping out the bigger, tweaked Soundcraft console - hate to move it), and let the downstream processing take out chinks here and there as it will, and hope there's "enough left over" so that it still sounds good in a typical mid-fi TV sound system, or is even passible in a 3" speaker. I told them the best way to do this is a post mix for TV, but there isn't time or money for that. Sigh. Any thoughts/experiences appreciated. Frank Stearns Mobile Audio -- |
#2
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Dealing with the TV Audio Signal Path
Frank Stearns wrote:
But here's the quest for wisdom... Should I pre-compress my feed to the TV folks in the hopes that AGCs and other downstream manglers will be less inclined to trip? All I have is a DBX 1066 that I've not yet modified. It's fairly clean (more so than the RNC I used to have), but it's still a bit of a polluter. I always do. I tend to use an Aphex 108, but I have used the RNC as well. The key is just to do some slow grainriding so that the AGC systems don't go berserk. The 1066 will be fine... you don't want to do so much compression that you actually notice it. Also do a light high pass. Or, should I just get as uber-hi-fi as possible (such as schlepping out the bigger, tweaked Soundcraft console - hate to move it), and let the downstream processing take out chinks here and there as it will, and hope there's "enough left over" so that it still sounds good in a typical mid-fi TV sound system, or is even passible in a 3" speaker. The high pass will prevent the AGC stuff from going berserk, and the TV guys will high pass everything more many times by the time it gets to that 3" speaker. You could add a little presence peak to make intelligibility on a TV speaker a little bit better, but I don't normally bother. Doing a super-hi-fi mix is probably not a good idea... if anything you might want to do an extra-close-in mix that is less accurate than the feed you have. I told them the best way to do this is a post mix for TV, but there isn't time or money for that. Sigh. Any thoughts/experiences appreciated. TV is bad. --scott -- "C'est un Nagra. C'est suisse, et tres, tres precis." |
#3
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Dealing with the TV Audio Signal Path
I remember hearing a Bernstein live concert on PBS about 25 years ago that
was so compressed the dynamic range must have been less than 6dB. I stuck a dbx expander on it, and the expander was unable to do anything. I'd compress the hell out of it, and hold back a bit on the peak level of the final compressed signal to reduce the chance of further compression down the chain. I don't think the people doing the broadcast care whether it sounds good, just as long as the quietest passages are nice and loud, and the loudest don't "blast". |
#4
Posted to rec.audio.pro
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Dealing with the TV Audio Signal Path
"Frank Stearns" wrote ...
I'm doing a live Messiah recording for a new, major client, and was also asked, "by the way, can you live-feed the tv people?" Well, yeah, a monitor mix from a toy console under adverse conditions... The local tv production folks assure me they "don't do anything" to the audio, but who knows what "auto" settings are switched in on their gear and worse, what happens when it leaves their hands and heads into the cable system. Shudder. Does "live-feed the tv people" mean providing a stereo mix in case the 6-oclock news people show up to shoot 5 minutes of B-roll? Or is this a full-up live TV broadcast? Is it one of the over-the-air channels in town, or is its some cable channel (or "community access"?) Can you "characterize" the expected audio path by listening to the channel beforehand? For example one would expect a significant difference between the well- funded local PBS operation vs. Portland Cable Access, vs. one of the commercial stations with doubtful classical music engineering talent. I am running a KM183 pair (with diffraction spheres) in AB stereo with 50 cm separation. This is a departure from my usual MS config, but given that I can't perfectly check the mechanical & electrical alignment "live" this should work well. (In various tests here, and with a friendly competiter's D183s, I've been pleased how this sounds -- mis-aligned MS, on the other hand, can be awful.) Also running two solos, four spots in a rather large orchestra, and two choir outriggers. The main pair should do most of the work, perhaps all -- depends on how the room shapes up when it's full of people. Are you going to handle tracking and the live stereo mix separately? Let me know if you need an A2 assistant :-) But here's the quest for wisdom... Should I pre-compress my feed to the TV folks in the hopes that AGCs and other downstream manglers will be less inclined to trip? All I have is a DBX 1066 that I've not yet modified. It's fairly clean (more so than the RNC I used to have), but it's still a bit of a polluter. Or, should I just get as uber-hi-fi as possible (such as schlepping out the bigger, tweaked Soundcraft console - hate to move it), and let the downstream processing take out chinks here and there as it will, and hope there's "enough left over" so that it still sounds good in a typical mid-fi TV sound system, or is even passible in a 3" speaker. My experience has been that the closer you can get your feed to what they are actually going to use, the less likely they are to feel the need to "muck it up". I told them the best way to do this is a post mix for TV, but there isn't time or money for that. Sigh. Any thoughts/experiences appreciated. Let me know if you need any assistance (equipment or labor). Any excuse to hear a good live local performance of Messiah. :-) 503-869-1741 |
#5
Posted to rec.audio.pro
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Dealing with the TV Audio Signal Path
Frank Stearns writes:
[...] Hi Frank, I'm not a recording engineer but an electrical engineer (emphasis in DSP) who has recently been involved with NTSC broadcast TV audio (the decoder side, but this required intimate knowledge of the encoder). Now I admit that I don't know what auxiliary processing a station does to an audio signal (compression, etc.), but based on knowledge of the BTSC (MTS) encoder my advice would be to simply feed it the best signal you can. A good signal along with a good encoder/decoder can yield at least 60 dB SNR these days, and you'll have a good 14.5 kHz of bandwidth. By the way, did you say whether this was an HD station or an old analog station? An HD station should have even better performance what with the use of digital source encoding, channel coding, etc. -- % Randy Yates % "Though you ride on the wheels of tomorrow, %% Fuquay-Varina, NC % you still wander the fields of your %%% 919-577-9882 % sorrow." %%%% % '21st Century Man', *Time*, ELO http://www.digitalsignallabs.com |
#6
Posted to rec.audio.pro
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Dealing with the TV Audio Signal Path
"Goldsmiths" wrote ...
Wow, TV sound sure is getting ripped. I assure you that, at least in mobile units, we care a hell of a lot about the sound. Good to hear that at least some people in television care about audio, but I fear that you represent rather a minority of the industry. But, unfortunately, most of the bad stuff happens after it leaves us. Exactly the problem. I agree with Randy; send the best signal you can. That is one philosophy, but you are placing youself completely at the mercy of whatever/whomever is downstream (vs. perfoming some measures of pre-emptive processing under YOUR control.) The old days of monitoring on-site with a 3inch Auratone are, thankfully, just about gone. I'm certain that big multi-million mobile units have halfway- decent audio monitoring, at least for the audio control person. There are enough viewers out there who actually have the gear to tell the difference to make it worth your while. I agree. But I believe that there are way too many people running the distribution systems who still have the "3-inch speaker philosophy" (and matching monitoring equipment :-) If it will ultimately be HD/surround, or even just digital, it will be worth it. Indeed. But that is a big "IF", and seems unlikely when audio for TV was only mentioned as an afterthought. |
#7
Posted to rec.audio.pro
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Dealing with the TV Audio Signal Path
In article ,
Frank Stearns wrote: I'm doing a live Messiah recording for a new, major client, and was also asked, "by the way, can you live-feed the tv people?" Well, yeah, a monitor mix from a toy console under adverse conditions... The local tv production folks assure me they "don't do anything" to the audio, but who knows what "auto" settings are switched in on their gear and worse, what happens when it leaves their hands and heads into the cable system. Shudder. I am running a KM183 pair (with diffraction spheres) in AB stereo with 50 cm separation. This is a departure from my usual MS config, but given that I can't perfectly check the mechanical & electrical alignment "live" this should work well. (In various tests here, and with a friendly competiter's D183s, I've been pleased how this sounds -- mis-aligned MS, on the other hand, can be awful.) Also running two solos, four spots in a rather large orchestra, and two choir outriggers. The main pair should do most of the work, perhaps all -- depends on how the room shapes up when it's full of people. But here's the quest for wisdom... Should I pre-compress my feed to the TV folks in the hopes that AGCs and other downstream manglers will be less inclined to trip? All I have is a DBX 1066 that I've not yet modified. It's fairly clean (more so than the RNC I used to have), but it's still a bit of a polluter. Or, should I just get as uber-hi-fi as possible (such as schlepping out the bigger, tweaked Soundcraft console - hate to move it), and let the downstream processing take out chinks here and there as it will, and hope there's "enough left over" so that it still sounds good in a typical mid-fi TV sound system, or is even passible in a 3" speaker. I told them the best way to do this is a post mix for TV, but there isn't time or money for that. Sigh. Any thoughts/experiences appreciated. Frank Stearns Mobile Audio -- One thing to add to the previous comments: Make sure it mono's ok. David Correia www.Celebrationsound.com |
#8
Posted to rec.audio.pro
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Dealing with the TV Audio Signal Path
Goldsmiths wrote:
Wow, TV sound sure is getting ripped. I assure you that, at least in mobile units, we care a hell of a lot about the sound. But, unfortunately, most of the bad stuff happens after it leaves us. I agree with Randy; send the best signal you can. The old days of monitoring on-site with a 3inch Auratone are, thankfully, just about gone. There are enough viewers out there who actually have the gear to tell the difference to make it worth your while. If it will ultimately be HD/surround, or even just digital, it will be worth it. I agree to send the best quality sound possible, but don't send sound with too much dynamic range. Because the bad stuff will happen, and it can be pretty bad. It may not happen until you get to the cable company... it may not even happen until it gets to the user's TV set... --scott -- "C'est un Nagra. C'est suisse, et tres, tres precis." |
#9
Posted to rec.audio.pro
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Dealing with the TV Audio Signal Path
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#10
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Followup: Dealing with the TV Audio Signal Path
Thanks for all the suggestions and responses.
It comes down to resources (time and money). Ideally, I'd bring my mobile control room or better yet, do a proper post-mix and lay it back to video. The first is not logistically feasible; the latter is that old time and money thing. (Yet they'd like to have a $10K+ audio job for $500. Yeah, I like to shop like that too.) Fortunately, they agreed to recording the dress tonight and I'll be able to check a number of things then, and even fiddle a bit back here in a good mix environment on Saturday in preparation for the Sunday recording. At that time I'll get a rough comp and EQ setting for the tv audio feed. If there's any interest, I'll try to post a followup next week. Thanks again, Frank Stearns Mobile Audio Richard - thanks for your offer. I will try to call you later today; I'd be up for perhaps a backup HD24 and maybe some backup preamp channels if you want to swap those for admission. -- |
#11
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Followup: Dealing with the TV Audio Signal Path
I assume you're familiar with this, but I'll mention it anyhow...
It's been my experience that performers play around 1dB to 3dB louder (at peaks) during the performance than they do during rehearsal. |
#12
Posted to rec.audio.pro
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Followup: Dealing with the TV Audio Signal Path
"William Sommerwerck" writes:
I assume you're familiar with this, but I'll mention it anyhow... It's been my experience that performers play around 1dB to 3dB louder (at peaks) during the performance than they do during rehearsal. Yup. Multiply that by 90 singers and 25 instrumentalists and you've got some serious SPL. g One nice thing about 24 bit digital is the nice big dynamic window. If (in my old-timer's mind) the visualized mechanical VU only hits a -20 most of the time, no worries. Lots of room for the 20 dB peaks! And I'll be watching the comp's GR for the tv feed. Thanks for the reminder, Frank Stearns Mobile Audio -- |
#13
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Dealing with the TV Audio Signal Path
wrote in message .. . YEs, our unit is set up to interface with the TV folks and we have good monitoring. I'm sure though that when it leaves the uplink is the last time anything like what we produce is going to be seen along the chain. Ah, the dreaded "U" word...uplink. If the backhaul feed is, indeed, going by satellite be very careful of where you sit your peaks. A lot of the common satellite chains, both analogue and digital, are set to preserve RF bandwidth rather than sound quality and clipping can onset as low as around +10dBu (it varies a bit with frequency so I can't be more specific). We used to have to have a hard limiter in circuit at about +8. However, the good news is that the signal to noise, especially on digital links, is pretty good so you can afford to back off the overall level a bit to preserve dynamic range (at least until it hits the compressor at the main transmitter!). My caution on clipping aside, as a recently retired TV engineer (who DID care about audio) I'll join the chorus of "just give them the best you can". Bob |
#14
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Dealing with the TV Audio Signal Path
Tim Perry wrote:
A radio engineer I knew had a favorite saying: TV people only notice audio whan it isnt there. I made a parallel recording of the opening of the Copenhagen Opera via FM broadcast - via antenna, not via cable! - and via NICAM tv-sound. The presenter mic to music mix ratio was idiotic on both transmissions. The TV audio seems to be just as it was from the sound board. It still takes up a lot of disk space on some harddisk. Kind regards Peter Larsen |
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