Preamp difference : if it's not the frequency, not the slew rate, and not the harmonics, what is it ?

[abbey road d enfer]

In parametric equalisers you can get phase distortion occurring at the crossover points (Low/Low Mid, Low Mid/Hi Mid, Hi Mid/Hi -

Having tested dozens of analog parametric EQ's, I've never seen one that doesn't behave as a Minimum-Phase device.
It takes a lot of effort (or stupidity) to design an EQ that's not MP.
Some digital parametric EQ's, designed by geeks, had weird phase behaviour.

 

[abbey road d enfer]

The preference i have experienced in recording is to record flat and not apply EQ or compression (unless absolutely necessary) on input path but on the monitor or mixdown path - leaving a clean untouched recording and applying the EQ etc later.

It's a respectable POV, but not everybody agrees.
It's commendable but imposes a specific constraint of making sure the signal that's recorded is close enough to the final expected sound, which takes time with mic choice and placement only; that's why some prefer resorting to EQ to achieve a similar goal.

You can’t un-EQ or uncompress a recording.

Actually un-EQing is not uncommon, since bell curves can be easily reversed. Shelves may be a little more difficults bit it's achievable.
What is very hard and sometimes impossible to undo is HPF and LFP.

Anyway that’s a preference that is down to the individual engineer but I know very few who use record path EQ

I unabashedly do.

 

[JohnRoberts]

I vaguely recall Consumer Reports were sued by Bose and lost due to some negative subjective remarks, which highlights the perils of subjectivism.

Bose Corp. v. Consumers Union of United States, Inc., 466 U.S. 485, was a product disparagement case ultimately decided by the Supreme Court of the United States. The Court held, on a 6–3 vote, in favor of Consumers Union, the publisher of Consumer Reports magazine, ruling that proof of "actual malice" was necessary in product disparagement cases raising First Amendment issues, as set out by the case of New York Times Co. v. Sullivan. Wikipedia

Actually Bose lost, but Consumer reports felt the sting from Bose's lawyers.

Music interpretation can (should) be emotional, opening the door variability and inconsistency, and has to be taken with a few pinches of salt.
I have little experience with Peavey, a friend had one, a little guitar amp he said had insufficient power output. I measured it with a dummy load, and it met the stated output, like 50W, but it did not sound "loud". I suspected too low even order harmonics, but did not do a deep dive into to causes.

Peavey has sold more than a few guitar amps, and all kinds of audio equipment.

I shared a common lab space with the guitar amp engineers, they knew how to make them loud.

JR

 

[kags]

Al Schmitt famously answered the question of “What’s you favorite EQ?” with the answer “I wish I could answer that, but I don’t really use EQ.” He further explained that applied to tracking and mixing. Other engineers and produces with similar success will smash sounds into shape however necessary while tracking

Do what works for you. This is art.

I do agree that most gentle EQ can be undone if necessary, but compression has to be managed more carefully during tracking.

 

[JohnRoberts]

Al Schmitt famously answered the question of “What’s you favorite EQ?” with the answer “I wish I could answer that, but I don’t really use EQ.” He further explained that applied to tracking and mixing. Other engineers and produces with similar success will smash sounds into shape however necessary while tracking

Back in the bad old days of noisy magnetic tape media there was a benefit from applying any needed HF boost prior to tracking and HF cut afterward during mix down. This provided some free tape hiss noise reduction.

Do what works for you. This is art.

more or less, a mix of science and art.

I do agree that most gentle EQ can be undone if necessary, but compression has to be managed more carefully during tracking.

It depends on the nature and criteria of the project. I can imagine cases for both being used.

JR

 

[FIX]

One important factor that seems to be missing is that in the "olden" days, all mic pres and eqs were in the console, so even though their may have been a lot of high and low phase shift, they are all in sync. Relative phase shift between channels still has a clear image and is not as random as todays use of different preamps and eq for different things.

It's all about the glue.

 

[RoadrunnerOZ]

It's a respectable POV, but not everybody agrees.
It's commendable but imposes a specific constraint of making sure the signal that's recorded is close enough to the final expected sound, which takes time with mic choice and placement only; that's why some prefer resorting to EQ to achieve a similar goal.

There’s no constraint if the same EQ can be applied post recording - boosting any frequency pre-record can reduce input headroom especially for high transient sounds. There certainly can be an advantage in using EQ to tape because of the characteristics of tape/tape recorders especially if high boost is needed and you don’t want to amplify tape hiss later. With near silent digital recording you don’t get the same problem.
When you have a room full of people doing a recording on a time budget you don’t always get the luxury of time to spend on tweaking sounds which could be later done in the mix, can also be a vibe killer. If the right mic is used and the placement is good then you shouldn’t need to pre-process. If the room has issues or spill is a problem, then certainly you need to fix that - no point in recording stuff you need to get rid of later if you can fix it on the spot.
Certainly if the mix is going to be done in another studio, by another engineer then you want to deliver the best possible product.

 

[vintageampfixer]

One important factor that seems to be missing is that in the "olden" days, all mic pres and eqs were in the console

Not always. In the late 80s / early 90s, I did lots of set ups for several different broadcasters in the UK, Africa & Middle East which had separate mic amps racked closer to the mic location so the line level signals could do the longer hop back to the desks. It was partly to do with the booths having the ability to be shared between mix locations ... and I think party due to what was en vogue. There were advantages in slightly lower end-to-end noise on the mics plus it opened up the use of lower cost cable but disadvantages if the sound operator wanted to tweak the mic amp gain setting.

 

[RoadrunnerOZ]

Actually un-EQing is not uncommon, since bell curves can be easily reversed. Shelves may be a little more difficults bit it's achievable.
What is very hard and sometimes impossible to undo is HPF and LFP.

Bit difficult if EQ and then compression have been used together - if tape saturation and recorder frequency response is included in the mix even harder to undo. Digitally recorded yes - easy enough if you have the exact same EQ and know what the original settings were. In the days when outboard gear and track count was limited and you didn’t want to bounce to another track on tape to use a device twice, (the same device may be needed twice to process the same sound but in different areas) then you would use it on record and also on mixdown.
Edit: also to be able to use the same device on two different tracks and you only have one unit.

 

[abbey road d enfer]

Bit difficult if EQ and then compression have been used together

For sure, compression is quite hard to undo, whether it's on its own or combined with any other FX. Expanders are generally not as common as compressors.

- if tape saturation and recorder frequency response is included in the mix even harder to undo.

Tape "sound" is impossible to undo.

easy enough if you have the exact same EQ and know what the original settings were.

If the EQ is audible enough to make you want to undo, you don't need to know what it was. You should be able to undo it, as long as you have the proper tool, i.e. a true parametric EQ. Of course if someone has applied EQ at 1kHz and the only choice you have to undo it is 800Hz or 1.2kHz, you're out of luck.

My formative years were on mixers that did not have EQ on the tape returns, so EQ'ing and compression at take was almost mandatory. I can't track if the rest of the context is not close to the final mix.

Seems we have drifted apart from the OP.

 

[RoadrunnerOZ]

I spent a fair bit of time on consoles with flip on EQ and the large faders - the little faders were used as sends to tape. Many preamps have (and had) EQ and compressors built in and this could lead to recordings with hard to treat issues.
Agreed - this is a long way from the original question.

 

[Tubetec]

The person who started this thread seems to have vanished .

I went to see a band I know today at a small outdoor festival ,
I got to sit just behind and a few feet above the sound desk ,
The PA system was modern Dynacord with a Midas M series digital desk , I wasnt impressed with the finger acrobatics required to get to the pages or menus to access the controls , and despite eq,dynamics and gating on every channel it still didnt sound very good , in fact Id say any halfway decent analog mixer could have much sounded better .

Misuse of compression Ive found to have a detrimental effect on vocal performances in particular , a good vocalist will have there mic technique down , typically leaning back a bit from the mic on louder parts and in closer on quieter sections , if a vocal is completely squashed the singer cant control their own dynamic range as well .

 

[Newmarket]

- you can put all the test signals you like and analyse with all the distortion and spectrum analysers under the sun and end up nowhere.

Well if you do it right you end up with a series of meaningful and reproduceable results. So there is that.

 

[RoadrunnerOZ]

Well if you do it right you end up with a series of meaningful and reproduceable results. So there is that.

Yeah - they create a standard to set a benchmark target of achievable results to and you certainly don’t want to be at the low end. But strangely enough especially in the amplifier world sometimes too flat is flat. Some really well spec’d gear I’ve been given in the past to evaluate and put on show for sale has had disappointing results, some has been really good. Microphones, mic pre’s, compressors, EQ’s, audio interfaces, powered studio monitors, PA systems etc were all put to the test and up for sale.

 

[abbey road d enfer]

The PA system was modern Dynacord with a Midas M series digital desk , I wasnt impressed with the finger acrobatics required to get to the pages or menus to access the controls , and despite eq,dynamics and gating on every channel it still didnt sound very good , in fact Id say any halfway decent analog mixer could have much sounded better .

I don't think the end result can be entirely chalked up to the gear.
I've seen many festivals where different SE's had wildly different results, using the same gear.
I've always been concerned by how SE's are particular about gear. I think that a good SE should be capable of good results on almost any decent gear.
It used to be relatively simple when mixers were analog, now digital mixers have so wildly differing OS it's created almost irreconcilable sects.
I agree with you on the difficulties of operating a mixer with a small control surface (often a smartphone). Doesn't let itself to quick reaction.

Misuse of compression Ive found to have a detrimental effect on vocal performances in particular , a good vocalist will have there mic technique down , typically leaning back a bit from the mic on louder parts and in closer on quieter sections , if a vocal is completely squashed the singer cant control their own dynamic range as well .

Misuse of anything is bound to be detrimental.
I've seen (heard) many singers "playing" the microphone; some do it right, many do it wrong.
I'd rather have a well adjusted compressor than a singer that ends its lines holding their mic at arm's length.

 

[RoadrunnerOZ]

My first hands on experience with a digital screen console was at an indigenous festival going live to air - I was given a 10min rundown on this Yamaha unit, then a 10min sound check, the unit was a scene call up type of affair so you couldn’t see everything at once. I had to do one set with a band I had mixed before but always on an analog system. Once I got used to it I quite enjoyed it - it was somewhat similar to using an 8 motor fader control surface with assignable rotarys, which I was well used to but the overall impression was a bit claustrophobic and it was too easy to call up the wrong channel scene. It was like running a DAW at a gig - similar EQ displays and inserts etc.

 

[Mihobro]

Interesting observations, while digital circuits only vary according to obvious failures, like dropping or frozen bits evident especially when the signal is using that bit a lot, at certain volume levels, analog circuits are much more prone to variation and "flavor". Care spent on testing and matching components can bring some consistency, but it really takes an effort to match things. When repairs were done on preamp circuits we always ask if it is paired and replace the identical part in both channels.
An interesting aside is that a change in analog console, both designed by Greg Mackie, resulted in dramatically less feedback. i wonder if anyone else has seen this phenomenon? I strongly suspect improvement in the summing amps.

 

[JohnRoberts]

Interesting observations, while digital circuits only vary according to obvious failures, like dropping or frozen bits evident especially when the signal is using that bit a lot, at certain volume levels, analog circuits are much more prone to variation and "flavor".

A poorly understood issue with some early digital systems was running out of processor headroom, or ability to finish multiple calculations concurrent with the sample rate intervals.

Care spent on testing and matching components can bring some consistency, but it really takes an effort to match things. When repairs were done on preamp circuits we always ask if it is paired and replace the identical part in both channels.

Effective use of NF (negative feedback) can minimize path differences due to device variations.

An interesting aside is that a change in analog console, both designed by Greg Mackie, resulted in dramatically less feedback. i wonder if anyone else has seen this phenomenon? I strongly suspect improvement in the summing amps.

Feedback? Are you talking about acoustic feedback in live performance monitor systems? There are multiple factors that can affect susceptibility to feedback but summing amp design is not on that list.

JR

 

[Mihobro]

Sorry, I meant acoustic feedback. Always fighting for gain in those PA jobs, (Same powered speakers, same room, same mic.)

 

[JohnRoberts]

Sorry, I meant acoustic feedback. Always fighting for gain in those PA jobs, (Same powered speakers, same room, same mic.)

I know a little about feedback. One of my patents was for the LEDs over the GEQ sliders in Peavey FLS equalizers.

Gain before feedback in live monitor systems is all about path frequency response (hottest frequency typically runs away first). Microphones and their patterns, monitor loudspeaker response and their patterns all matter.

Where the monitor send is taken from in the mixer channel strip (pre or post channel EQ), could impact ability to deliver good monitor levels depending on how and how much the strip EQ is used.

In my experience summing amps have zero impact on any of those factors.

JR