Vintage Audio Part 8: EQ's and Dynamic Range Processors

[William]

Yes, I know most audio folks don't believe in necessarily using them. But when you factor in less than ideal room dynamics that most people face in reality plus personal preferences in sound it seems like a tool to make suble adjustments may not be a bad idea.

I've been playing around with a modified Pioneer RG-9 Dynamic Processor in one of my systems and once I figured out less is more, there are definitely times I think is works well. Going too high with the threshold can illicit a sort of "breathing" effect between the enhanced highs and quiet lows. Seems to help in recording LP's to cassette...yes, I make cassettes to send to our daughter who digs them. Thinking I might want try out a DBX 3BX or a DBX 118 sometime. I haven't played with an EQ yet but I may.

Any of you audio folks use or used one or both, or would you not be caught with one in your system?






W.

[marciero]

I'm not an audiophile, but it sounds like the dynamic range processor is a type of compressor, as compressors limit the dynamic range.

Stuff you probably know:
Dynamic range limiting is part of the mastering process for any professionally done recording. It smooths out the gain structure-essentially cutting off the high level peaks that might lead to "clipping"-overloading of the audio circuitry, smoothing out the overall levels. It also ensures uniform volume across different tracks and that the gain is consistent with audio componentry and standards; eg, you dont have to adjust the volume differently when going from recordings by different artists. In that way, they are different from EQs in that they are not designed to shape the sound tonally. Compressors are also standard equipment in studios for use during the recording process for similar reasons.

Stuff you may or may not care to know:
According to the lore, in the 60's, Roger McGuinn of the Byrds ran his 12-string guitar through two studio compressors in series with both maxed out, one overdriving the other (driving the engineers nuts, so the story goes). That may have been the first use of a compressor as an "effect", and was a hallmark of the Byrds' sound. Since that time compressors have been used as an effect by guitarists to help shape the sound, not so much tonally but to smooth out the sound and sort of give it polish. Think Nashville telecaster style. Is commonly used by rock guitarists too. It can also simulate sustain, as the initial attack of the note-often with a pick- is chopped, and the note incrementally "released", so instead of attack and decay, the volume is more constant over the duration. The breathing effect you describe is consistent with high settings of this processor.


Opinion of non-audiophile:
So..
For listening to music, the rationale you have- different rooms may enhance different frequencies, and also preference- seems to apply to EQs but not so much to compressors. On the other hand for recording LPs to cassette sounds like judicious use of this processor might be appropriate.

[Duende]

I worked as a mastering engineer for many years. Still do the occasional project here and there... and I can’t think of any good reason to have compression or limiting if dynamics of commercially relaxed music that’s already been mastered. Particularly with today’s trends were the audio is often smashed to bits to increase all available perceived volume. Look up “loudness wars” in audio mastering and you’ll see what I’m talking about.

Btw, that breathing your hearing is just the compressor “pumpin” because it’s being improperly triggered by bad attack/release times. It’s a populist sound for some dance music kick drums these days, but otherwise it’s no good.

EQ devices are another story. If your stereo is too bassy try moving your speakers away from your walls. If it’s too trebly try placing the speakers on more solid stands. EQ’s are really the most dangerous piece of musical gear ever created. .

[Bob Ross]

Originally Posted by Duende

I can’t think of any good reason to have compression or limiting if dynamics of commercially relaxed music that’s already been mastered.

^^^This. And any combination of upward/downward expansion is just as inappropriate.

btw, there's really no such thing as "less than ideal room dynamics" unless your listening room has an open window next to a freeway, or shares space with a machine shop. There are less than ideal room responses but those are spectral and temporal issues. And they are best addressed by mechanical rather than electrical means. Fix the room; don't fix [sic] the hi-fi.

[Peter P.]

I use an equalizer with my system, a simple 5-band Audio Control 520b. I've had that thing since the '70's. The bridge rectifier recently blew a diode. I replaced all 4, and a couple associated capacitors, and it should be good for another 40 years!

Why not?

Many subwoofers come with software to flatten the response when measured in your room. I see no difference.

Adjust until it sounds good to you, and enjoy the music.

[William]

My understanding is that it is a range expander, not a compressor. Theory/thought being that music is compressed...recording teqniques using reduction of transient peaks, compression of loud levels, and upward manipulation of soft levels. Range expanders are supposed to try restore those ranges. How well it does that I'm sure is a fun debate. As I said, Im just playing around with one and I think it does well in moderation.

That being said I've never heard a stereo really reproduce live music well. Not to the point you can't tell the difference between live and recorded. The sound of live music has so much going on between highs and lows of different musical instruments plus the effects of sound distance and refraction that I don't think any two channel recording will ever (at least not to this point) be able to faithfully reproduce it. But, we do the best with what we have, hear what we hear, like what we like, and tinker toward the currently unobtainable.







W.

[benb]

Compressors are freaking great actually.

Not into Hi-Fi/Audiophile at all anymore. But I would love to have a nice Compressor to use with the TV and other sources. Something with adjustable threshold/ratio/attack/release/makeup gain just like a compressor intended for music production. Get the compressor to make all the quite lines legible and keep the gunshots and poorly mixed music from being deafening.

Even if it was HDMI In -> Compressor -> HDMI Out and you could just stuff it between the source and whatever you were playing the audio through.

Modern TV/Movie content seems horrific in terms of having too much dynamic range for home viewing. It seems like it's gotten a lot worse with stuff that is done by say Amazon than the traditional studios. We've been watching Man in the High Castle and I'm sitting there riding the Volume all the time. Sometimes it's so bad we turn the subtitles on in English!

I've gone through several compressors in my electric guitar rig.. I've stuck with an optical compressor based on the famous old LA-2A studio compressor.

"Range Expander/Enhancer" stuff is often talked about as being bunk.

It's essentially a pre-amp that is set up to amplify on a curve in terms of dynamics & EQ. Probably not that different than an Overdrive or Boost used with musical instruments. These can work well.

I think the issue is when the source audio is "crushed" from the modern mastering style the device is going to have a limited ability to restore it. Source material has a ridiculous amount of dynamic range compared to finished products that a listener buys and puts on.

I play a Tele, don't really play much country really. The "Nashville Tele" sound is stereotypically the MXR Dynacomp or "Ross" style compressor with a ton of compression. I am not fond of those at all for me. I enjoy that sound in recordings.. but those things are really noisy when you're playing, they are really popular with guitarists but are almost the most primitive type of compression circuit out there.

There is a lot of compression effects in use by David Gilmour in Pink Floyd performances... (I have this stereotype that Hi-Fi/Audiophile like Pink Flody for some reason.)

[marciero]

Originally Posted by William

My understanding is that it is a range expander, not a compressor. Theory/thought being that music is compressed...recording teqniques using reduction of transient peaks, compression of loud levels, and upward manipulation of soft levels. Range expanders are supposed to try restore those ranges. How well it does that I'm sure is a fun debate. As I said, Im just playing around with one and I think it does well in moderation.

That being said I've never heard a stereo really reproduce live music well. Not to the point you can't tell the difference between live and recorded. The sound of live music has so much going on between highs and lows of different musical instruments plus the effects of sound distance and refraction that I don't think any two channel recording will ever (at least not to this point) be able to faithfully reproduce it. But, we do the best with what we have, hear what we hear, like what we like, and tinker toward the currently unobtainable.

W.

Ah. So like an un-compressor. It would try to undo what a lot of really, really expensive studio gear was designed to DO. I can think of a simple-minded way to do this. You could pick a median level and attenuate (or amplify) any level below (or above) that median by an amount proportional to the the difference between it and the median. This would definitely expand things. But generally speaking undoing or fixing things that were created in the original recording has mixed results. Would be curious how these things work.

[rwsaunders]

How about a de-noiser unit. Are they primarily used for recording?

[Duende]

The “un-compressor” is more commonly referred to as expansion. And it doesn’t really work. The basic idea was that with a slow attack and fast release time, loud dynamics such as snares or transient peaks found in the attacks of notes would be allowed to pass through... and the rest of the body would then be clamped down on by the compressor. This in theory increases or expands the amplitude difference between the initial attacks and the remaining music body.

However music varies way too much for it to be truly effective. And that’s just in one song. Now consider having the same attack/release settings across all genres of music.. and you clearly see that in practice the notion is rather absurd.

[benb]

Originally Posted by marciero

Ah. So like an un-compressor. It would try to undo what a lot of really, really expensive studio gear was designed to DO. I can think of a simple-minded way to do this. You could pick a median level and attenuate (or amplify) any level below (or above) that median by an amount proportional to the the difference between it and the median. This would definitely expand things. But generally speaking undoing or fixing things that were created in the original recording has mixed results. Would be curious how these things work.

I'm sure this is likely to be analog.

It's probably just a tuned amplifier.

Here is the thing though, the more you try to expand it the more you're amplifying stuff, the more noise it adds. There's no real way around it. The more crushed the recording is (loudness war) by the studio engineer the more noise the expander would add.

Compressors have the same issues as they are amplifying the quiet parts to bring them up. Good ones don't add a ton of noise, bad ones do.

There is a *ridiculous* amount of de-noising in every recording by the time it gets to the listener. Especially anything with electric instruments. It kind of makes me laugh about a lot of the audiophile stuff and tube stuff cause the entire experience is 100% artificial. If you were in the original room when the recording was done it would not sound at all like what the audiophile thinks it sounds like. Even absolutely amazing guitar tube amps have a "broken" level of noise by audiophile/home listener standards especially as they are setup to approach even moderate rock tones.

[Duende]

Stereos can not produce live music well simply because the storage mediums - records, tapes, CD, digital downloads do not have near the dynamic range found in actual live music. Therefore everything has to be compressed to control the dynamics and provide for the squeezing of the live captured audio into these container mediums.

In someways records still remain a good medium, as instead of a hard cut like their digital counterparts. The signal just gets noisy. But it’s a good noise, like looking into a clear lake and still being able to see/discern things.

This notion about de-noising however is simply not true. Noise reduction hit its peak in the late 80’s with Dolby SR and was used primarily for tape recorders. However, since then tape recorders have mostly switched to digital mediums, tape itself improved to have more headroom, and electronic amplifier technology has improved so much that the once INCREDIBLY expensive top of the line SR noise reduction units are worthless and you can’t give them away.

I can’t think of any live recording as of late that’s used noise reduction. Dance music, high gain metal guitarists might use noise gates, but that’s simply for a triggering effect to let certain sounds be audible. Not noise reduction to filter out noise constantly. Sound Designers use noise reduction to treat/restore damaged or archival audio... but again is a small small segment of the market.

[benb]

Originally Posted by Duende

This notion about de-noising however is simply not true. Noise reduction hit its peak in the late 80’s with Dolby SR and was used primarily for tape recorders. However, since then tape recorders have mostly switched to digital mediums, tape itself improved to have more headroom, and electronic amplifier technology has improved so much that the once INCREDIBLY expensive top of the line SR noise reduction units are worthless and you can’t give them away.

I can’t think of any live recording as of late that’s used noise reduction. Dance music, high gain metal guitarists might use noise gates, but that’s simply for a triggering effect to let certain sounds be audible. Not noise reduction to filter out noise constantly. Sound Designers use noise reduction to treat/restore damaged or archival audio... but again is a small small segment of the market.

You're thinking of consumer level noise reduction.

I'm talking about studio stuff. The studio engineers are doing a TON of stuff to remove noise from any recording that isn't 100% acoustic. DAW software makes it pretty easy actually.

A classical recording of an orchestra done with tons of microphones might not have to have much noise reduction.

Even clean electric guitar is getting a huge noise reduction in the studio, especially if it's a single-coil guitar, P-90 guitar, etc..

Tube amps produce a wall of white noise. In something like a metal guitar application the noise gate before the amp does nothing to address the wall of white noise the amp itself makes. Get up close in a small quiet live scenario (almost impossible for metal) and it's amazing. In a recording environment they're often even putting the speaker cabinet in another isolated room or a sound isolation box. The box/room is miced up and run through the production equipment and then piped back into monitors or IEMs. (There are lots of different setups)

The most amazing thing about this is even Youtube videos where guitarists demo equipment the guys are removing the noise in post production. The demo videos are incredibly misleading for some equipment.

You can almost never hear this noise in a big venue cause the background noise of the crowd is too loud. A stadium tour the stuff is getting run through all kinds of noise reduction/gates/whatever in the PA as well I think. You'd hear it if you were at sound check.

The noise can be so bad as a player you have to get used to it, and you need to learn tricks to hide it from a live audience too sometimes if the whole environment can't be tuned to get rid of it.

Even modest consumer stereo systems actually do a great job reproducing their input. If you have a audiophile system it's probably capable of some serious loud output too so if it was cranked up the dynamic range is probably fine. It's just the input material is already incredibly heavily processed. Most audiophile recordings don't reproduce the in room sound realistically at all. The dynamic range is way off, but also for lots of genres a ton of cleanup has been done.

[William]

Originally Posted by benb

Compressors are freaking great actually.

Not into Hi-Fi/Audiophile at all anymore. But I would love to have a nice Compressor to use with the TV and other sources. Something with adjustable threshold/ratio/attack/release/makeup gain just like a compressor intended for music production. Get the compressor to make all the quite lines legible and keep the gunshots and poorly mixed music from being deafening.

Even if it was HDMI In -> Compressor -> HDMI Out and you could just stuff it between the source and whatever you were playing the audio through.

Modern TV/Movie content seems horrific in terms of having too much dynamic range for home viewing. It seems like it's gotten a lot worse with stuff that is done by say Amazon than the traditional studios. We've been watching Man in the High Castle and I'm sitting there riding the Volume all the time. Sometimes it's so bad we turn the subtitles on in English!

In surfing the web on this topic I've come across a few write ups of people using compressors for exactly that purpose.






W.

[Duende]

Originally Posted by benb

You're thinking of consumer level noise reduction.

I'm talking about studio stuff. The studio engineers are doing a TON of stuff to remove noise from any recording that isn't 100% acoustic. DAW software makes it pretty easy actually.

A classical recording of an orchestra done with tons of microphones might not have to have much noise reduction.

Even clean electric guitar is getting a huge noise reduction in the studio, especially if it's a single-coil guitar, P-90 guitar, etc..

Tube amps produce a wall of white noise. In something like a metal guitar application the noise gate before the amp does nothing to address the wall of white noise the amp itself makes. Get up close in a small quiet live scenario (almost impossible for metal) and it's amazing. In a recording environment they're often even putting the speaker cabinet in another isolated room or a sound isolation box. The box/room is miced up and run through the production equipment and then piped back into monitors or IEMs. (There are lots of different setups)

The most amazing thing about this is even Youtube videos where guitarists demo equipment the guys are removing the noise in post production. The demo videos are incredibly misleading for some equipment.

You can almost never hear this noise in a big venue cause the background noise of the crowd is too loud. A stadium tour the stuff is getting run through all kinds of noise reduction/gates/whatever in the PA as well I think. You'd hear it if you were at sound check.

The noise can be so bad as a player you have to get used to it, and you need to learn tricks to hide it from a live audience too sometimes if the whole environment can't be tuned to get rid of it.

Even modest consumer stereo systems actually do a great job reproducing their input. If you have a audiophile system it's probably capable of some serious loud output too so if it was cranked up the dynamic range is probably fine. It's just the input material is already incredibly heavily processed. Most audiophile recordings don't reproduce the in room sound realistically at all. The dynamic range is way off, but also for lots of genres a ton of cleanup has been done.

Sound isolation/tracking techniques and the noise reduction processing you first mentioned are not the same thing, particularly in regards to the premise of your original post. Where you basically stated noise reduction is so inherent to audio production that it renders the remaining audio to be artificial.

I’ve literally either mixed, mastered, produced, or performed on hundred of records for numerous majors and independent record labels. Not to mention I was chief engineer at a high end recording studio for 14 years. And my experience could not be more different than yours on this matter.

Let’s just agree to disagree.