Home » R/E/P Archives » Dan Lavry » SSL EQ Electronics
| SSL EQ Electronics [message #65469] |
Thu, 12 May 2005 21:30  |
 nrosborough
Messages: 63
Registered: March 2005
Location: Brooklyn, NY |
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I posted this on the not-so-active Hardware Board, so I'll try this in a real forum. I was wondering if I could get some insight into the differences between SSL E series and G series equalizers. They just don't seem to make this information readily available, though I've heard that the E series, which SSL calls their "classic EQ", was the best one they made.
-nathan rosborough
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| Re: SSL EQ Electronics [message #65578 is a reply to message #65469 ] |
Fri, 13 May 2005 10:30  |
nrosborough
Messages: 63
Registered: March 2005
Location: Brooklyn, NY |
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thanks guys, that clears it up a lot for me
-nathan rosborough
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| Re: SSL EQ Electronics [message #71104 is a reply to message #65549 ] |
Fri, 10 June 2005 11:41 |
ssltech
Messages: 4264
Registered: May 2004
Location: Florida (previously UK) |
Platinum Member |
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| zmix wrote on Fri, 13 May 2005 14:39 |
The major difference in the sound of the two different designs was due to the shape of the HF and LF shelf EQ, the E series having a gentle 1st order (6dB per octave) slope and the G series having a more severe 2nd order slope (12dB per octave). In addition the E series has a shelf/bell switch on the LF which allows for some nice options on drums...
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Gotta correct a couple of details on this one...
The slope of the HF/LF bands can't be measured in db/octave, only the hi-pass and lo-pass filters...
The E series (82E02 -brown knob- and 82E242 -black knob-) had switchable bell/shelf on top AND bottom. The G-series when it was introduced took this option away and replaced it with "X3" and "÷3" range selectors for the midrange. This was because another well-known designer had created a product that people were oing crazy over in the intervening years... causing them to "Focus Right" on the EQ design, if you catch my drift (the ISA110 had similar ranges and controls... think about it!)
Okay, one other thing that miraculously made their way into the G-series design was the constant-Q behaviour in the midranges. Now, as you booseted more (for example... same thing happened in cut) the slope remained the same (slope represented by 'Q') so the frequencies where the response deviated from flat moved further away from the center frequency and the affected area widened. Previously, the E-series had left the two 'corner frequencies' (not a technically accurate use of the term) in teh same place so long as you left the bandwidth control alone, so the more you boosted, as the "mountain" got taller, the sides got steeper.
Basically that's the big difference. As the mountain gets taller, in E series, the sides get steeper and the base of the mountain remains the same width. In the G series, the sides remain the same steepness as the boost is altered, and so as the mountain gets taller, the base gets wider.
In the J-series version, they added an E/G switch to allow either configuration.
Now that we've defined the major differences, here's why I detest the G-series version: If I'm dipping a ring tone on a previously recorded tom (for example) I might need a farily narrow but reasonably deep notch, in order to dip it down a bit, but without sucking too much 'tone' energy out around it... With the 'G', the further I dip, the wider it gets... exactly what I don't want!
Well, that's the major points... G series can be useful in boost, but if you are a habitual twiddler who adjusts the 'Q' interactively with the ± cut/boost controls, it may be less of an imposition.
However, you CANNOT get a narrow, deep notch from a G. NOr do you get the option of bell and shelf on BOTH top and bottom bands.
Before long, SSL relented and started making and selling ht eold E EQs in the new G's that it was shipping, as an option. an option that most people ordered!
Keith
| MDM (maxdimario) wrote on Fri, 16 November 2007 21:36 |
I have the feeling that I have more experience in my little finger than you do in your whole body about audio electronics..
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| Re: SSL EQ Electronics [message #80439 is a reply to message #71104 ] |
Sat, 30 July 2005 18:46 |
Paul Frindle
Messages: 380
Registered: May 2004 |
Active Member |
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| ssltech wrote on Fri, 10 June 2005 17:41 |
| zmix wrote on Fri, 13 May 2005 14:39 |
The major difference in the sound of the two different designs was due to the shape of the HF and LF shelf EQ, the E series having a gentle 1st order (6dB per octave) slope and the G series having a more severe 2nd order slope (12dB per octave). In addition the E series has a shelf/bell switch on the LF which allows for some nice options on drums...
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Gotta correct a couple of details on this one...
The slope of the HF/LF bands can't be measured in db/octave, only the hi-pass and lo-pass filters...
The E series (82E02 -brown knob- and 82E242 -black knob-) had switchable bell/shelf on top AND bottom. The G-series when it was introduced took this option away and replaced it with "X3" and "÷3" range selectors for the midrange. This was because another well-known designer had created a product that people were oing crazy over in the intervening years... causing them to "Focus Right" on the EQ design, if you catch my drift (the ISA110 had similar ranges and controls... think about it!)
Okay, one other thing that miraculously made their way into the G-series design was the constant-Q behaviour in the midranges. Now, as you booseted more (for example... same thing happened in cut) the slope remained the same (slope represented by 'Q') so the frequencies where the response deviated from flat moved further away from the center frequency and the affected area widened. Previously, the E-series had left the two 'corner frequencies' (not a technically accurate use of the term) in teh same place so long as you left the bandwidth control alone, so the more you boosted, as the "mountain" got taller, the sides got steeper.
Basically that's the big difference. As the mountain gets taller, in E series, the sides get steeper and the base of the mountain remains the same width. In the G series, the sides remain the same steepness as the boost is altered, and so as the mountain gets taller, the base gets wider.
In the J-series version, they added an E/G switch to allow either configuration.
Now that we've defined the major differences, here's why I detest the G-series version: If I'm dipping a ring tone on a previously recorded tom (for example) I might need a farily narrow but reasonably deep notch, in order to dip it down a bit, but without sucking too much 'tone' energy out around it... With the 'G', the further I dip, the wider it gets... exactly what I don't want!
Well, that's the major points... G series can be useful in boost, but if you are a habitual twiddler who adjusts the 'Q' interactively with the ± cut/boost controls, it may be less of an imposition.
However, you CANNOT get a narrow, deep notch from a G. NOr do you get the option of bell and shelf on BOTH top and bottom bands.
Before long, SSL relented and started making and selling ht eold E EQs in the new G's that it was shipping, as an option. an option that most people ordered!
Keith
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I actually designed this EQ (and much of the other stuff that got re-done in the G series) and most of what you say above is correct  Just some points from memory that may help:
The G series EQ (as well as new input stages and much other stuff I did) was developed to address the increasing criticism we were getting for 'harsh sounding consoles'.
The EQ was of specific concern since the trend for tight boosting in the mid ranges (started by Hugh Pagham and co) was beginning to wane. And obviously I/we looked closely at other EQ sections people were beginning to prefer at the time.
The band pass sections were not constant Q - but they did incorporate a widening of the effective bandwidth as boost or cut was increased. This was done to give greater apparent sonic effect for less total boost and therefore persuade people (hopefully) to do less sharp EQing - cos it was sharp EQ that made harsh sounding mixes. But you are right in saying that the cut situation was non ideal because high effective Qs needed for percussion taming etc were no longer really available - it was a compromise. In fact this parameter can be changed easily in the circuit by only one resistor change per section - but of course several other switches (or controls) would have been needed and we didn't have them available on the panel.
The times 3 freq switches were needed to increase the range of the EQ so that more subtle stuff could be done at the freq extremes (again taking emphasis away from predominantly mid range focus of the E series EQ). Sadly, because the control knobs were so small and the control backlash between the multi-ganged pots was so great we couldn't support this range on the existing knobs without it being quite unstable and almost impossible to set. So reluctantly we had to hijack the bell/shelf buttons to get the ranges without increasing knob sensitivity.
The HF and LF sections were also modified to change their character radically. They were 2 pole designs but one of the poles was (almost) fixed so the action of that pole changed depending on freq and gain settings, being most active towards the extremes of setting - BTW they are not strictly symmetrical in boost and cut either. For the HF section this was arranged to open up the response at higher freq settings and create a slight 2 pole style undershoot in the upper mid ranges when in boost (again taking emphasis away from boosting mid ranges that were harsh). This made the EQ sound very much more focussed in the HF region and created much more 'air'. In the LF section was arranged to create a partial 2 pole overshoot and undershoot at the lowest freq settings that provided warmth to the bass regions without excessive lower mid boost. All these decisions were based soley on what sounded best.
By way of history and why we were limited to exisiting panel controls; the G series initiative started out as retro-fit cards. The idea was that one could extract the existing sections and 'upgrade' with the new cards as they became available - the old ones remaining available for those that still prefered them. I was taken off SSL's new digital project and set up in an old out house down the drive we used to call the 'Bothy', to do this in relative isolation and peace (it was short-lived though). As things progressed (by the time I had re-designed the Mic/line input sections) it was thought that the card swap initiative alone would be insufficient to sway people against the emerging trends (and other consoles), so a complete (largely cosmetic) re-vamp was launched. But this of course still retained the limitations of the existing panel metal work, channel PCB and overall architecture of the E Series console. The project was on-going and progressive even after the G series name was launched. By the time I was returned to the digital project I had re-done most parts of the electronics in the channel strip, putting right many other long-standing issues with freq response and instability along the way. There were many other quality issues that also needed addressing in the centre section too, but I was off the case by then and I don't know what was done after that. Shortly after this I left SSL.
On the subject of EQ - later I was able to address all the issues I have ever wanted (some of which you mention) by being able to design a digital EQ with several selectable types to cover the widest range of use I could think of - one type of which does the gentle boost/sharp cut routine that is so useful for percussion taming and controlling resonance
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| Re: SSL EQ Electronics [message #81110 is a reply to message #80981 ] |
Wed, 03 August 2005 16:39 |
Paul Frindle
Messages: 380
Registered: May 2004 |
Active Member |
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| zmix wrote on Wed, 03 August 2005 05:16 |
Paul,
Both of the SSL EQ circuits occupy a unique place in recording history. Do you suppose it was due to a unique design, or a collection of useful features unavailable in one place before?
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From a totally personal perspective I would honestly have to answer that it was most probably (almost certainly was from what I saw at the time) a combination of many circumstances created by the ensemble of the whole console and the use the musicians and recording artists made of it at the time.
ILME it is quite wrong for a designer of circuits to consider that those circuits in themselves are the whole essence of an artistic event. In reality it is always the combination of the circuits - within a system - of which the whole is used by artists - to create something that is acclaimed as innovative and new - which appeals to people at a particular time. As such everyone in the whole process is party to the event - not one particular sector or one particular technical availablity. However much it is human nature to search for one defining fact that enables something like this, in truth it is as much down to chance as it is engineering, a kind of fortunate synergy of engineering, art and fashion idiom. And it is essential (but probably rarer than it should be) that a technical designer NEVER forgets that the success or failure of his design is as much in the hands of the user as it is in his own innovation or skills in the design of the product. We are all slaves to the art - not the other way around!
So taking all the above into account, the SSL phenomena was basically started by the imagination of Colin Sanders to provide a console that had dynamics/noise gate and parametric EQ in every channel of an in-line console - most probably what he himself wanted and couldn't get. When he initially designed the gate section of the compressor he was most probably thinking of suppressing tape and background noise - how could he have known that someone working (largely by chance) in an unfinished and partially untreated studio on a console that was all but mothballed because it was so controversial, would re-purpose this to produce the gated reverberant drum sound that launched a whole new fashion and propelled this console to the top of the league?
And when he designed the EQ he was probably thinking technically logical and defensible dependancies of gain and Q - how could he have known that this intitally over tight clinical dependancy would encourage people to produce the 2-3KHz tightly boosted EQ that also typified this era and was awash in everything at the time? It would be tempting to claim retrospectively that the genius was wholly in the technical design team (as undeniably there was aplenty) - when in fact an equally large part of the genius was in the use that highly imaginative and inventive people with open minds actually put it all to So when the G-series EQ was made it was designed within the limitations of the existing panel to appeal to what we considered the new artistic paradigm would actually be - mostly by 'being in touch',listening and applying 'artistic extrapolation'. As you can imagine this was no mean task - the spontaneous success of the E series was a tough act to follow and have the optimism to expect to pull off a second time within a new fashion environment. At this point you are actually trying to lead new fashion rather than simply responding to what's already there - it requires a whole different way of thinking - particularly if you are already the market leader - design responsibility doesn't get much greater than this! Sales executives will always urge you to copy or incrementally improve some existing design all the clients are on about. But of course this isn't enough to change whole idioms and most certainly wasn't the spirit that produced the E series console and fuelled it's subsequent success. This stress might largely explain the passions it all aroused at the time?
Everytime I design something my major personal drive behind making all that effort and taking it all so very very seriously is to provide something that I hope will inspire the user to do something artistically astounding, whether it involves the need for absolute purity in some processes or downright risky 'distortions' and blatant character in others. Of course I provide a technical manual and a load of illustrative set-ups, but most of all I want to HEAR what people will do with it. The only reason I was ever driven to doing design - something that I was perhaps always ill-qualified for - was that I wanted to hear the music. And that holds true to this day.
I have the deep impression that Colin Sanders was similarly motivated when he initially launched into his console design. BTW - with all this you might begin to understand why passion and conflict figured highly amongst many of us invloved in the natural design process when Colin was in the driving seat in those early days. And I can honestly say that in my whole career I have never met anyone who could drive me up the wall with greater ease - or anyone for whom I had greater respect
Apologies for the long rambling reply 
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| Re: SSL EQ Electronics [message #97682 is a reply to message #84269 ] |
Fri, 14 October 2005 22:10 |
ssltech
Messages: 4264
Registered: May 2004
Location: Florida (previously UK) |
Platinum Member |
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Paul,
I missed this thread after a month or so of no replies to my post. -Thanks for the extra info!
I never bothered to check the absolute constancy (or otherwise) of the Q, but I did realise that it was doing something that I really didnt like, so after retrofitting a couple of channels, we took those cards out and went back to the E series.
After a while, we built our own retrofit cards (AAD -Amazon Audio Developemnt- equalisers) and finally made something that was what we wanted. We tried to sell them, but people's enthusiasm for the project before the fact wasn't matched by a willingness to dig into their pockets after the fact. -Later on, I worked with Leif Mases who used them, liked them, and decided to build his own; thus the Maselec ones were also brought into being. (-I just saw Leif at the AES on the Prism stand as a matter of fact. -I think we spent an hour and a half catching up on old times!)
As regards discouragement of tight boosts in high mids, I always liked the Amek dual-concentric approach, which encouraged the user to mimic Dick Swettenham's "Olympic Equaliser" in that as you boosted, the Q got broader, and as you cut it got narrower. In the case of the Amek, you still retained full control, but grabbing both controls as a pair was quick and intuitive. 'Note-hunting' before narrow dipping just meant a quick twiddle of the lower (outer) of the dual-concentric controls.
I've always been a huge fan of SSLs as user products. Total Recall was what drove Amazon to be by far the biggest studio in the north of England in the mid-1980's. That, the lack of any competition in Manchester or anywhere else in the North, and the international explosion of all those Northern bands, -most even taking off in the USA- meant that I was jumped from tech-ing to full-time engineering, (just because I knew how to do it!) and we all had more work than you could shake a dirty stick at!
I vaguely remember the 'bothy' being featured in a B/W photo ad for SSL before the G series came out. -Tag line was something like: "If it sounds good in here, it'll sound good in your place", wasn't it?
Anyhow, The EQ didn't make music sound the way it did, neither did the mic pres, neither did the buss amplifiers. that's always been my view. It was the users. Wrenches don't fix cars, mechanics do. -All the same, a mechanic knows a good wrench from a cheap one, and I ALWAYS used SSLs. In those heady days we had frequent visits from Neve, who had just installed the very first V-series at Strawberry in Manchester, begging us to buy a V. -The complete lack of a parametric EQ was the primary reason we never did (Neve finally got the hint at the third revision -the V3) along with no recall (It took until 1988 for the VR to come out, I think!)
Anyhow, you're a fine man, with some fine history, much of which has steered my life. Without SSL, I'd still be a UK "Northern git" of a tech, instead of the US "Southern git" of a tech I am now!  
Keith
| MDM (maxdimario) wrote on Fri, 16 November 2007 21:36 |
I have the feeling that I have more experience in my little finger than you do in your whole body about audio electronics..
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