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Limiting and more limiting and more – Manley SLAM! User Manual

Page 16

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At this writing, there has been a very disturbing trend in CD

mastering to apply levels of audio processing to CDs formerly

only used by “aggressively-processed” radio stations. These

CDs are audibly distorted (sometimes blatantly so) before any

further Optimod processing. The result of 8400 processing can

be to exaggerate this distortion and make these recordings

noticeably unpleasant to listen to over the air.

There is very little that a radio station can do with these CDs

other than to use conservative 8400 presets, which will cause

loudness loss that may be undesired in competitive markets.

There is a myth in the record industry that applying “radio-

style” processing to CDs in mastering will cause them to be

louder or will reduce the audible effects of on-air processing.

In fact, the opposite is true: these CDs will not be louder on air,

but they will be audibly distorted and unpleasant to listen to,

lacking punch and clarity.

Another unfortunate trend is the tendency to put so much high

frequency energy on the CDs that this cannot possibly survive

the FM pre-emphasis/de-emphasis process. Although the 8400

loses less high frequency energy than any previous Orban

processor (due to improvements in high frequency limiting

and clipping technology), it is nevertheless no match for CDs

that are mastered so bright that they will curl the vinyl off car

dashboards.

We hope that the record industry will come to its senses when

it hears the consequences of these practices on the air. Alas,

at this writing, they have shown no signs of doing so.

Anyone—please feel free to quote anything I’ve posted on the

board. I am trying to bridge the broadcasting and mastering

communities, and the best way is to “get the word out.”

This subject has suddenly heated up on the Broadcast.net

radio-tech mailing list. Broadcast engineers have become very

concerned about the clipped and distorted material that they

are being presented with. In fact, one well-respected poster

went so far as to propose a minimum peak-to-average ratio

spec for material that was to be considered “broadcast quality,”

and proposed that stations reject any material breaking this

spec.

The consensus was that radio stations need “radio-mastered”

mixes. These can have all of the EQ and compression applied

to the standard release, but need to have the peak limiting and

clipping greatly backed off or eliminated. This will retain the

flavor added by the mastering, but not the distortion!

In this age of broadband Internet connections, it would be per-

fectly feasible to service stations with “radio-mastered” singles

from a password-protected website. Most stations would prefer

uncompressed files to retain quality and prevent any issues

with “dueling algorithms,” as stations often compress later on

in the chain, either when they store the material to hard disk for

on-air playback, or in their studio-to-transmitter links (STLs).

http://www.orban.com/

16

Limiting and more limiting and more...

The following is a small section of the Orban Optimod-FM, 8400

owner’s manual. This is a compressor used by radio stations be-

fore they broadcast the music signal. Orban is, by far, the leading

company building broadcast limiters in the world. This eloquent

piece posted on by Robert Orban serves as yet

another warning for those that intend to use hyper-compression

on their mix.

We completely agree with Robert’s post and the suggestion to cre-

ate a few masters with lesser amounts of limiting. Hopefully the

password protected web-site can become available and producers

and/or record companies can post optimized mixes for radio.

Perhaps Robert’s post was aimed more at the abuse of multi-band

limiters, but the SLAM! can be made to hyper-compress, and/or

distort which may cause problems further down the chain than just

the basic CD intended for home listening. It is just not that simple.

For example, one might clip a track deliberately for a certain ef-

fect or for apparent loudness. If during the song, a section has less

highs, a station’s multi-band limiter may try to lift the HF bands,

exagerating the HF harmonic distortion and making it more than

ugly. In fact, it might make it un-playable by some stations.

What might we suggest? Musicians might try to play at consistant

volumes. Mix engineers might limit individual tracks and sub-

groups more than the mix. They might also want to rely more on

the mastering engineer for final limiting, and their expertise and

experience with how product translates to broadcasting. Mastering

engineers have to consider the broadcast chains. A&R people have

to realize that songs sell records, and a louder CD won’t make

much difference. In fact, a CD that is too loud, too aggressive, too

in-your -face may also be too exhausting to listen to for more than

one or two songs - but A&R guys don’t read manuals like this.

In more direct practical terms, run the mix 3 times and create 3

versions with different depths of limiting. This gives the mastering

engineer more to work with. The mastering engineer can aslso do

the same thing and create 3 masters. Then the only trick is making

sure the right parties get the right version, without misdirection.

Another idea mentioned earlier is limiting individual tracks, and

sub-groups. One can also create loudness just in how tracks are

mixed and EQ’ed. In fact, absolutely great mixes need very lit-

tle or nothing done in mastering (everybody’s elusive goal). The

worst mixes need the most processing. Slapping a drastic proces-

sor on a bad mix is just that, and doesn’t make it a great mix or

make real mixing easier or ‘mixing’ something that everybody can

do as long as they have that drastic processor. Just gotta mix well

first.

Perhaps the best advice is to do what experienced engineers have

done for 50 years with limiters. Use them gently and carefully. A

few dB may be better than none, and better than 10 dB of limiting.

This, of course, means you have to use your ears and meters and

not presets. The idea is not how much limiting you can get away

with, but how much and how little is optimum and still sounds

good. The usual answer is 2-6 dB on a mix (assuming fast attack

time only).

In simple quick comparisons, we generally tend to prefer the

choice that is louder and most people can be fooled into thinking

X is ‘better’ than Y even with a fraction of a dB more volume. This

is really one place where a bit of extended listening is required to

determine which is actually better to listen to for any longer dura-

tion. Transients and dynamics can be very nice too.

Maybe you were just thinking, how much (or little, right) should

you limit the mix for the mastering engineer. So now you have

to consider how much limiting is appropriate for the artist and

song, how much is appropriate for the CD and that audience and

how much is appropriate for radio, for the label, for vinyl dance

tracks..... If only one version is allowed - be careful, avoid regret-

table squash.

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