AM Radio Eq Curves? Broadcast mic technique?

Archived from groups: rec.audio.pro (More info?)

"michaelthomas" <nospam@bettahitz.biz> wrote in message
news7Tbd.12709$Fe6.5429565@news4.srv.hcvlny.cv.net...
>
> can anybody tell me the EQ curves for AM Radio (WABC etc)?

most (US) AM radio stations have a flat response up to the processor.

an AM processor(s) generally have a great deal of AGC followed by
compression (one to 7 bands) followed by limiting. followed by a NRSC
filter.

in addition many units have a way to adjust modulation symmetry to obtian up
to 125% modulation of the positive peaks.

adjustment of the compression settings can determine how the station will
sound in relation to the other stations in the same market.

>
> i've read conflicting reports of top rolloff at 3khz and others at 7khz
>

the bandwidth limitations are here
http://edocket.access.gpo.gov/cfr_ [...] r73.44.htm

most (US) AM stations have an overall frequency response form 50 Hz to 7.5
kHz. some can pass a FM "proof" to 15 kHz.

don't worry about the 75 uS pre emphasis / de-emphasis issue. its outside
your control anyway.

> i'll be recording a voice over for an AM Radio ad and want to get the
vocal
> to sit in the correct pocket.
>
all radios ads that are produced by "agencies" and are distributed the
stations nationwide use the same ad regardless of AM or FM.

just keep in mind that you final mix is going to be compressed by the
station so go light on the squishers.

> is there a technique that engineers are using to get that broadcast and
> hollywood voiceover sound...like mic placement more towards the chest etc?

eat the mic. (1 to 3 inches)

i
> know RE20 is the choice mic but looks like the $500mil man Stern is using
a
> TLM

most radio studios have less than ideal acoustics, consequently close
micing, compression and gating are employed.
Howard's studio is set up for television therefore is atypical.


>
> also any advice on where i should have my RMS sit would be helpful.
>
>
3 dB compression on the vocal
none on the music bed


one pass through a finalizer is optional (dbx ddp, quantum, aphex dominator
or similar product or feature of your digital editor)

have fun with it now

Tim

Archived from groups: rec.audio.pro (More info?)

"Robert Orban" <donotreply@spamblock.com> wrote in message
news:WrSdnazIiIyRIujcRVn-uw@giganews.com...

> The audio response of the average AM radio is down 6 dB at 3 kHz and down
> about 20 dB at 5 kHz. For this reason, it is very unwise to use
"smile-curve"
> type equalization in production for AM. Be sure there is plenty of energy
in
> the lower midrange and avoid excessive bass boost. A modest amount of
> compression is appropriate. Also, de-essing can be very important because
of
> the transmission pre-emphasis that is often used. Make sure that your
> production are not "essey."

In the new issue of Radio World, a honcho from Clear Channel proclaims that
they will henceforth bandlimit their AM stations to 5kHz.

Peace,
Paul

Archived from groups: rec.audio.pro (More info?)

"Robert Orban" <donotreply@spamblock.com> wrote in message
news:WrSdnazIiIyRIujcRVn-uw@giganews.com...
> In article <w86dnTN6V4QXV-3cRVn-tw@adelphia.com>,
> timperry@noaspamadelphia.net says...
> >
> >
> >
> >"michaelthomas" <nospam@bettahitz.biz> wrote in message
> >news7Tbd.12709$Fe6.5429565@news4.srv.hcvlny.cv.net...
> >>
> >> can anybody tell me the EQ curves for AM Radio (WABC etc)?
> >
> >most (US) AM radio stations have a flat response up to the processor.
> >
> >an AM processor(s) generally have a great deal of AGC followed by
> >compression (one to 7 bands) followed by limiting. followed by a NRSC
> >filter.
> >
> >in addition many units have a way to adjust modulation symmetry to obtian
up
> >to 125% modulation of the positive peaks.
> >
> >adjustment of the compression settings can determine how the station will
> >sound in relation to the other stations in the same market.
> >
> >>
> >> i've read conflicting reports of top rolloff at 3khz and others at 7khz
> >>
> >
> >the bandwidth limitations are here
> >http://edocket.access.gpo.gov/cfr_2003/octqtr/47cfr73.44.htm
> >
> >most (US) AM stations have an overall frequency response form 50 Hz to
7.5
> >kHz. some can pass a FM "proof" to 15 kHz.
>
>
> The FCC requires stations to comply with the NRSC2 bandwidth standard,
which
> drops like a rock at 10 kHz. So a US AM station that passes a "proof" to
15
> kHz is in violation of FCC Rules.
>
"proof" mode is with compression and filters disabled disabled or bypassed.
the filter is reinstalled or activated after testing.


> OTOH, the transmission chain (TX and antenna) are often flat to carrier
+/-
> 15 kHz, and, now that AM IBOC is being implemented, many are essentially
flat
> to carrier +/- 50 kHz.
>
> (AM "proofs," BTW, have not been legally required for some 20-odd years
now,
> except that AM stations still have to verify that the directional antennas
> meet licensed requirements. But there are no longer any audio
requirements.)
>

some stations particularly AMs still have analog telephone lines to the
transmitter. ocassionally a "proof" or frequency sweep is needed in the
course of troubleshooting.


> Prior to the transmission audio processor (often an Optimod), audio plants
in
> AM stations are garden-variety with no special frequency response
contouring.
> The frequency response contouring and NRSC filtering usually occurs in the
> audio processor. While the NRSC1 standard specifies a "modified 75 us"
> pre-emphasis, this is not required by the FCC and many stations use a
> third-order (18 dB / octave) shelving pre-emphasis that starts at 2 kHz
and
> shelves off around 5 kHz. This pre-emphasis is not so much for noise
> reduction (when complemented by HF rolloff in the radio) as it is to
improve
> the intelligibility of speech through typical radios.
>
> The audio response of the average AM radio is down 6 dB at 3 kHz and down
> about 20 dB at 5 kHz. For this reason, it is very unwise to use
"smile-curve"
> type equalization in production for AM. Be sure there is plenty of energy
in
> the lower midrange and avoid excessive bass boost. A modest amount of
> compression is appropriate. Also, de-essing can be very important because
of
> the transmission pre-emphasis that is often used. Make sure that your
> production are not "essey."
>

probably the most important thing to check is mono compatibility. sometimes
production is received at stations that when left and right are combined
becomes distorted and unintelligible.