{"id":1868,"date":"2012-06-18T00:10:07","date_gmt":"2012-06-17T23:10:07","guid":{"rendered":"https:\/\/arpjournal.com\/?p=1868"},"modified":"2012-06-18T00:05:32","modified_gmt":"2012-06-17T23:05:32","slug":"all-buttons-in-an-investigation-into-the-use-of-the-1176-fet-compressor-in-popular-music-production","status":"publish","type":"post","link":"https:\/\/www.arpjournal.com\/asarpwp\/all-buttons-in-an-investigation-into-the-use-of-the-1176-fet-compressor-in-popular-music-production\/","title":{"rendered":"All Buttons In: An investigation into the use of the 1176 FET compressor in popular music production"},"content":{"rendered":"

1. Introduction<\/strong><\/h3>\n

The Urei\/Universal Audio 1176 is one of the most revered and popular compressors used in music production (Senior 2009). Bill Putnam introduced the design in 1966 and at the time it was the first peak limiter based on all transistor circuit (Universal Audio 2009). Many engineers attribute its famous sound to the FET and fast time constants and despite being through many revisions it is still a studio staple today.<\/p>\n

This paper aims to investigate why the 1176 is so widely used in production and will attempt to define its particular sonic signature. Due to the nature of popular music production and its under researched status in academia, information will primarily be gathered from textbooks and interviews given by contemporary music producers. From this information the author will attempt to ascertain how producers use the 1176 and undertake a series of subjective listening tests to verify their views.<\/p>\n

2. Hardware Compressor types and characteristics<\/strong><\/h3>\n

Tube (valve) compressors<\/strong> are more typically know as Vari-Mu. Unlike some designs, which simply have a valve in the circuit, a Vari-Mu compressor uses the valve for gain control.\u00a0 As pointed out by Case (2007) a circuit is sent to a valve by the level detection unit to alter its gain, which results in compression of the audio signal. Vari-Mu compressors do not have a ratio control and increasing amounts of gain reduction are achieved with louder levels (Izhaki 2008). Due to the use of a valve for gain reduction, Vari-Mu compressors are not as fast as the transistor-based units. This can make them a suitable choice for drum busses and full mixes when preservation of transients is desirable. The classic Fairchild 660\/670, Altec 436 and modern Manley Variable Mu are all examples of compressors that use valves for gain reduction.<\/p>\n

Optical compressors<\/strong> (more commonly known as Opto) use a light and a light sensitive resistor to alter gain (Case 2007). A bulb, illuminated by the level detection circuit, shines on a photo-resistant material to control the amount of gain change. As noted by Izhaki (2008) despite the fact that light is used, Opto compressors are slow to respond to rapidly changing musical dynamics making them a poor choice if quick clamping on transients is required.\u00a0 The classic UA LA-2A and modern Tube Tech CL-1B are examples of popular Opto compressors.<\/p>\n

VCA Compressors<\/strong> are arguably the most common design. These compressors use a transistor based voltage-controlled amplifier. When using a VCA in a compressors circuit the control voltage is derived from the input signal and any gain reduction is related to this level. In simple terms, more level, more voltage more gain reduction. VCA compressors are considered to be the most transparent of the hardware-based designs. As Paul White states \u201cIn very general terms, a well-designed VCA compressor will provide the most transparent gain reduction, which is ideal for controlling levels without changing the character too much\u201d (White 2003). Examples of VCA compressors include the dbx 160, the SSL console compressors and the Neve Portico 5043.<\/p>\n

FET Compressors<\/strong> use a Field Effect Transistor. Like the VCA, FET compressors can achieve very fast attack and release times. FET compressors also tend to colour the signal somewhat due to the FETs non-linear transfer function (White 2000). The 1176 and the Empirical Labs Distressor are both examples of FET compressors.<\/p>\n

2.1 The design of the 1176 and FET compression<\/strong><\/h4>\n

As noted in the current Universal Audio 1176 manual, the 1176 was designed by Bill Putnam in 1966 (2009). The manual goes on to claim that the original \u201cwas a major breakthrough in limiter technology-the first true peak limiter with all transistor circuitry offering superior performance and a signature sound.\u201d\u00a0 Rudolph (2001) states that the original 1176 came into existence after Putman had managed to design a remote controlled amplifier from the then new Field Effects Transistor (FET). He was able to find a way to use a FET as a voltage-controlled variable resistor and it was implemented as the gain-controlling element of the 1176 (Robjohns 2001). The current 1176 manual points out that the FET \u201cacts like a resistor whose resistance is controlled by the voltage applied to its gate. The higher the voltage applied to the gate, the smaller the resistance drain source will be\u201d Universal Audio (2009).<\/p>\n

It is also worth noting that the 1176 is a feedback compressor. This type of design sees the control side chain \u201cfed from the output end of the signal path.\u201d\u00a0 (Brice 1998) A feed-forward compressor on the other hand has the input to the side chain taken from the input end of the signal path. In the case of the 1176 the audio is sent through the FET and then a side chain signal is sent to the detector unit, which in turn sends the control voltage back into the FET.\u00a0 Consequently the feed-forward design can react a little quicker than the feedback. The Neve Portico 5043 is one of the few compressors that allows the user to switch between feedback and feed-forward signal flow.\u00a0 The manual for the 5043 claims that the feedback setting \u201cproduces a sweeter, warmer sound but is not as accurate if you need to protect a transmitter, for example\u201d (Neve 2011). However in real terms any delay introduced by the feed-forward design will be almost imperceptible and the actual gain reduction element will play a much larger part in how fast the compressor can react.\u00a0 It is also worth noting that by virtue of the feedback design some of the audio being compressed will have already attenuated. Could the sweet warm sound be attributed to this behavior?<\/p>\n

Due to the FET one major part of the 1176s sound is its ability to very quickly apply gain reduction. The current manual states that attack times are between 200-800 microseconds. Similarly the release times can also be very fast, ranging between 50 milliseconds and 1.1 seconds. As a comparison the Neve Portico 5043\u2019s quickest attack and release times are 20ms and 100ms (Neve 2011).<\/p>\n

Although the 1176 is often noted as having a fixed threshold, from analysis of a transfer function diagram (shown here in Fig. 1) from an out of print Urei 1176 manual the author noted that the threshold changes depending on the ratio. The current manual confirms this observation, stating, \u201cThe 1176 has been designed so that selecting higher ratios also raises the threshold level.\u201d Looking at Fig. 1 you can see that the knee also appears to change. At higher ratio\/thresholds the knee is harder which is obviously useful for controlling peaks while lower ratio\/thresholds have a softer knee for more subtle gain reduction. Shanks clarifies this observation in an edition of the Universal Audio Webzine when he notes that \u201cThe 4:1 and 8:1 ratios are commonly used for compression, 12:1 and 20:1 are used for peak limiting\u201d (Shanks 2003).<\/p>\n

\"\"<\/p>\n

Fig. 1 Urei 1176LN Transfer Characteristics courtesy of Urei 1989<\/em><\/p>\n

The \u201cprogram dependent\u201d nature of the 1176 is also worthy of consideration. According to an article in the 2003 edition of the Universal Audio Webzine entitled \u201cAll Buttons Mode\u201d the attack, release and ratio are all source dependent.\u00a0 Shanks points out that:<\/p>\n

The 1176 will faithfully compress or limit at the selected ratio for transients, but the ratio will always increase a bit after the transient. To what degree is once again material dependent. This is true for any of the 1176\u2019s ratio settings, and is part of the 1176\u2019s sound (Shanks 2003).<\/p>\n

From this quote it can be deduced that part of the 1176\u2019s punchy sound is due to how it compresses the attack portion of the transient lighter than the rest of the volume envelope. \u00a0 This program dependent nature of the device may also be one of the reasons it is often listed by producers and engineers as a compressor that can be used on practically any source with good results-more on this in chapter 3.1<\/p>\n

It should be pointed out that the 1176 has been through a series of revisions since it was first designed by Putnam in 1966. The following is a concise list of the versions and how they differ.<\/p>\n

    \n
  • Model A was the first 1176 released in 1967<\/li>\n
  • Model AB, also released in 1967 was an update that changed resistor values to reduce noise<\/li>\n
  • Revision B (1968) had some revisions to the preamplifier<\/li>\n
  • Revision C (1970) was the first of the blackface editions and introduced the 1176LN (low noise) circuit by Brad Plunkett<\/li>\n
  • Revision D (1973) featured a redesigned PCB (printed circuit board)<\/li>\n
  • Revisions E-H (1973 onwards) made a number of changes including a different transformer and output amplifier<\/li>\n
  • Current UA 1176s are claimed to be a faithful reissue of Revision D\/E<\/li>\n<\/ul>\n

    As with most musical equipment there is much debate between engineers concerning which revision is the best. Without having access to all of the above it is impossible to say and any observations would only ever be subjective at best. Due to financial constraints and availability the current UA reissue is tested in this paper. It would be interesting to compare the results with the same tests through other revisions.<\/p>\n

    2.2 When to use compression? <\/strong><\/h4>\n

    From analysis of interviews with producers and engineers it quickly becomes apparent that a significant number of them are ardent users of compression.\u00a0 Joe Chiccarelli candidly claims, \u201cUsing compression is like this drug that you can\u2019t get enough of. You squish things, and it feels great and it sounds exciting\u201d (Owsinski 2006 pg.60).\u00a0 John X simply states, \u201cI use it a lot. Not always in great amounts, but I tend to try to get some handle on peaks\u201d while Ed Seay notes that \u201cTo me, the key to compression is that it makes the instrument sound like its being turned up, not being turned down\u201d (Owsinski 2006 pg.59).<\/p>\n

    Before a discussion regarding how producers and engineers use compression, it is first worth clarifying the more general and obvious reasons for its use. Huber and Runstein (2010) note a variety of technical motives that includes minimizing extreme changes in dynamics that are too great for the music, to reducing obvious changes in source to mic distance during a take. Case (2007) also adds that compression can be used to \u201cimprove intelligibility and articulation\u201d while Izahki (2008) lists containing levels, balancing levels and loudening as three core applications.<\/p>\n

    However, many producers and engineers use compression as a creative tool. Both Case (2007) and Izahki (2008) discuss the use of compression to change the amplitude envelope of a sound. For example, a snare or bass drum transient can be pronounced by using a long attack and a short release to let the initial attack portion of the hit through before the compressor clamps down on the decay. Stavrou points out that if the attack is slow \u201cits as if the sick is much thicker\u201d (Stavrou 2003 pg. 121). The same tactic can be used on bass guitar parts, a slower attack time can let the plectrum attack through uncompressed with the compressor again pulling down the decay of the note therefore changing the envelope. Alternatively fast attack and release times, coupled with a high ratio and low threshold (for maximum gain reduction) can make parts of the sound that were not audible much more apparent. As Case says:<\/p>\n

    Through fast release compression, the engineer effectively turns up the later parts of the sound, revealing more of the decay of the snare, the expressive breaths between words of the vocal, the ambience of the room between drum hits, the delicate detail of the sax note and so on (Case 2007 pg. 147)<\/p>\n

    From research it seems engineers often use the 1176 to heavily compress drum busses and room mics, bringing out the ambience between drum hits. As noted by Adam and Ward (2011) this technique is referred to as \u201cAll-Buttons-In\u201d or \u201cNuke Mode.\u201d The current Universal Audio manual claims when all the ratio buttons are depressed at once the 1176 has a ratio that \u201cgoes to somewhere between 12:1 and 20:1\u201d (Universal Audio 2009). Shanks claims that attack and release times change with there being a \u201clag time on initial transients\u201d and from his description the compression curve is anything but gentle, he likens it to a \u201cplateau\u201d (Shanks 2003). It can be presumed that in this mode the 1176 turns into something that almost resembles a brick wall limiter that responds uncharacteristically slow to transients.<\/p>\n

    Distortion artifacts can also be deliberately introduced to the signal by using extremely fast attack and release settings. Izahki (2008) claims that low-frequencies distortion occurs when \u201cthe period of low frequencies is long enough for the compressor to act within each cycle rather than on the overall dynamic envelope of the signal.\u201d\u00a0 This issue is also discussed by Case (2007) who notes that when attack and release times are faster \u201cthan a fraction of the period of the sine wave, the compressor will attenuate during the peak (positive or negative) and uncompress in between the peaks.\u201d\u00a0 Obviously this is something to take into consideration, as it could indeed be a problem. However this artefact can and has been used as a creative effect in music production and the ultra fast time constraints of the 1176 should in principle make it a good tool for this job. In a 2003 edition of the Universal Audio Webzine Crane calls this \u201cThe 1176 Comp-Distortion Trick\u201d and goes onto describe in detail how it can be used to \u201cgive a male or female rock vocal an in-your-face sound that you can\u2019t get anywhere else\u201d (Crane 2003). Obviously the later part of his comment is perhaps marketing jargon but the additional harmonics created by this deliberate distortion theoretically could make a vocal appear more up front in a mix.<\/p>\n

    3. What do recording engineers say about the 1176? <\/strong><\/h3>\n

    From research carried out on interviews given by well-known producers and engineers the 1176 appeared to perform well under a number of circumstances. However from the authors\u2019 observations the most common applications seemed to be on vocals, bass guitars and drum buses\/room mics.<\/p>\n

    Vocals<\/strong><\/h4>\n

    Whilst discussing the mix of My Chemical Romance\u2019s \u2018Welcome to the Black Parade\u2019 Chris Lord-Alge comments that all vocals were treated with a \u2018Blueface\u2019 (Rev A-B) using 4:1 ratio and a quick release. Tom Elmhirst used a Blackface 1176 in conjunction with a Fairchild as part of the vocal chain for Amy Winehouse\u2019s \u2018Rehab.\u2019 Elmhirst states in an interview that the 1176 had been \u201cset with a very fast attack and a super-fast release, doing perhaps 10dB of compression\u201d (Tinegan 2007). Mike Shipley when asked what compressors do you like for vocals simply replied \u201cThe good old LA-2A and 1176s\u201d (Droney 1999). In another interview printed in the current 1176 manual, Shipley points out that he sets the attack and release depending on the song but adds he uses a faster attack if he wants more \u201cbite\u201d (Universal Audio 2009). An interesting \u201cpreset\u201d that appears occasionally in discussions is the \u201cDr Pepper\u201d setting. Charlie Clouser in an interview for the March 2004 edition of the Universal Audio Webzine states, that the setting has \u201cattack at 10 o\u2019clock, release at 2 o\u2019clock, and 4:1 ratio with tons of input level on the 1176\u201d resulting \u201cin a thickly compressed vocal with tons of texture.\u201d He notes the well-known engineer Jim Scott suggested this setting (Vdovin 2004).<\/p>\n

    Bass<\/strong><\/h4>\n

    In an article that surveyed a number of engineers and producers the 1176 \u2018topped the polls.\u2019 Senior says:<\/p>\n

    That the Urei 1176 convincingly topped the polls for bass processing in my survey of producers might raise an eyebrow, given what I\u2019ve said about it thus far. After all, fast compression can introduce serious distortion on slow-moving bass waveforms. However, as long as the time constants are kept away from the fastest settings (in other words, somewhat counter-intuitively, away from the higher-numbered, clockwise end of the control settings on the unit), the circuitry\u2019s tonal brightening and subtle FET distortion really help the bass to cut through the mix in a way that other designs can\u2019t match. The lowest ratio (4:1) is the most common choice, as evidenced by independent recommendations from Steve Churchyard, Chris Lord-Alge and Ralph Sutton, although Tom Elmhirst likes the result you get when you push in the 4:1 and 8:1 buttons together (Senior 2009).<\/p>\n

    It is interesting that Senior notes the 1176 seems like an unusual choice given the possibility of low frequencies distortion.\u00a0 However he does point out that using slower release times will resolve this issue.<\/p>\n

    Owsinski notes that bass tracks with little note definition can be improved by using an 1176 with an 8:1 ratio, a good amount of gain reduction and \u201cattack set to around noon and the release set to around 3 or 4 o\u2019clock\u201d (Owsinski 2006). These settings yield a long attack and a short release, which is presumably to alter the envelope of the note to increase articulation.<\/p>\n

    Drums<\/strong><\/h4>\n

    Hugh Padgham states in a 2005 interview that he used a pair of 1176s on two room mics which provided 90% of the drum sound for Phil Collins \u201cIn The Air Tonight\u201d (Flans 2005). Adam and Ward (2011) suggest using the 1176 with \u2018All Buttons In\u2019 on drum submixes to add a sense of urgency to the kit.\u00a0 Similarly Jay Newland also likes to build his drum mixes from the sound of an 1176. In a Universal Audio Webzine interview he claims that he will:<\/p>\n

    Always place one big mike, like a U47 (Neumann) or a ribbon mic such as a Coles or Royer, five or six feet in front of the drum. I try to get the whole drum set to sound good thru that mic and then put it thru an 1176. That\u2019s the secret weapon track. The 1176 compresses and makes it sound bigger and more present and a lot more exciting without having to crush it. I just it give a healthy 3-5db compression and turn up the gain a little bit \u2013 it sounds great! If I have that mono track, where the whole drum kit sounds balanced, then I can build a decent drum sound with whatever else I have (Vdovin 2003).<\/p>\n

    It should be noted that the 1176 does seem to be used regularly on spot mics but for the purposes of this paper the author is only concerned with full spectrum drum mixes such as busses or room mics.<\/p>\n

    3.1 Summarizing the behavior and sound<\/strong><\/h4>\n

    The behavior and sound of the 1176 can be summarized as follows:<\/p>\n