Avedis™ PSP E27


  • Software plug-in modeled after the Avedis™ E27
  • Oversampled for smoother analog type high frequencies
  • 3-bands with 9 frequencies per band with x2 for additional bands
  • ±16 dB of boost and cut
  • Shelving option for low and high frequencies
  • PA11 pre-amp stage for global output level control
  • Selectable high-pass filter
  • DRIVE feature increases input while simultaneously decreases output
  • Suitable for tracking, mixing, and mastering
  • Mac OSX – AudioUnit, VST3, VST, AAX and RTAS
  • Windows – VST3, VST, AAX and RTAS

Avedis™ PSP E27 Multistage Equalizer Plug-in


The PSP E27 is a multistage equalizer plug-in (VST3, VST, AAX and RTAS for Windows; AudioUnit, VST3, VST, AAX and RTAS for Mac OSX) modeled after our analog equalizer E27. The PSP E27 offers three-band equalization with nine selectable frequencies in a standard 500x package. The PSP E27 equalizer offers +/-16dB of boost/cut at musicially selected frequency ranges, and offers gentle saturation. Low and high filters can work in bell or shelf mode with a single click. The PSP E27 is suitable for both mixing and mastering and it offers an additional preamp stage for global level control. The PSP E27 EQ plug-in also catches nonlinear behavior of analog devices.

PSP is the sole developer and manufacturer of the PSP E27. Functionality and sound of the PSP e27 have been approved by Avedis Audio Electronics. PSP is responsible for all customer support.


High performance, musicality, ease of use and simplicity are the key elements of the E27. Extended frequency response, smooth, sweet, proportional Q design add up to great sonic features making the E27 invaluable in every project that I used it on.

Sakis Anastopoulos, DigiSound Mastering, Australia

Very hardware sounding, very familiar sounding. The PSP E27 EQ shows that the line (or separation) between excellent sounding hardware, and beautifully accurate coding necessary to obtain that same musical hardware sound “in the box,” is, for all intents and purposes, gone. In 2016, in the DAW, or out, especially with this PSP EQ, it’s all the same now.

George Daly, music executive, video and music producer, The Cars, Janis Joplin, Carlos Santana, The Tubes, Tool

The PSP E27 is a beautiful addition to the PSP line. At its heart is a faithful recreation of the Avedis hardware EQ. But its true strength lies in additional functions like the PA11 preamp module and x2 mode, which allows you to layer two sets of E27 modules in a single instance. This goes above and beyond the hardware. When you add the ability to switch from L/R to M/S operation, this plugin really packs a punch!

Blake Eiseman, music producer, mixer and sound engineer, Usher, Justin Bieber, Janet Jackson, James Brown, Boyz II Men, Arrested Development

Once again PSP delivers something special: new EQ model – based on hardware that may not be familiar to everyone but delivers a superb sound the lovechild  of a Neve/API

Steve Levine, Grammy Winning Producer, The Clash, Culture Club, Beach Boys, Motorhead, Ziggy Marley

The PSP E27 EQ sounds great! It has a certain warmth to it that does not sound digitally produced to my ears! The low end is huge & warm, yet not muddy at all! And the added 28K boost button is a nice addition as well! Brings a certain presence to a vocal even in a mastering situation!
Warren Sokol, Universal Mastering Studios, Hollywood, USA

Mininum System Requirements



  • Windows x32 or x64 (7, 8 or 10)
  • VST3 compatible application


  • Windows x32 or x64 (XP Service Pack 2, Vista, 7, 8 or 10)
  • VST 2.4 compatible application


  • Windows x32 or x64 (XP Service Pack 2, Vista or 7)
  • ProTools LE 8.0.0 or ProTools TDM 8.0.0 (or later)


  • Windows x32 or x64 (XP Service Pack 2, Vista or 7 or 8 or 10)
  • Pro Tools 10 or Pro Tools 11 or Pro Tools 12 (or later)

Mac (intel)


  • Mac OSX 10.6 – 10.11 or later
  • 32 or 64-bit host application capable of running AudioUnit plug-ins with Cocoa view


  • Mac OSX 10.6 – 10.11 or later
  • 32 or 64-bit VST 2.4 compatible host application


  • Mac OSX 10.6 – 10.11 or later
  • 32 or 64-bit VST 2.4 compatible host application


  • Mac OSX 10.6 – 10.11 or later
  • ProTools LE 8.0.0 or ProTools TDM 8.0.0 (or later)


  • Mac OSX 10.8 – 10.11 or later
  • Pro Tools 11,12 or later


Why frequencies up to 28kHz?

When you boost or cut a chosen frequency, it is shaped like a bell unless you push in the shelving button – then it’s half a bell where the top of it extends beyond the selected frequency. The top of the bell would be 28kHz, for example, but the curve leading up to the top starts at frequencies within the fundamentals, or within 20khz. So you will easily hear the effect at the very tail end of the audible spectrum without accentuating siblance or already aggressive high frequency in the source. PSP worked hard to have higher frequencies sound smooth and retain much of the harmonics found in the E27 hardware. After you hear it, it will be part of your eq vocabulary.

Is it a clone or a reproduction of anything?

The E27 is not a clone or a reproduction of anything else. Certainly some things about it have been influenced by gear of the past and present, but the overall design is unlike any other.

Is there a characteristic sound to this EQ?

One way to tell is to have some music playing on your favorite monitors, and suddenly patch the eq in the chain, but without any boost or cut and even with the IN button not engaged. Listen carefully and what you will hear is the characteristic sound. Though the frequency response is flat when no eq is used, an increase in depth is often noticed with this simple test.

Nothing is transparent; everything has a sound.

How narrow is the bandwidth?

The bandwidth (also called Q) varies depending on how much boost or cut there is. The more you boost, the narrower the Q, going from a fairly a broad bandwidth to medium.

Here is a graph of this Relative Q feature.

Why don’t the frequencies overlap?

Overlapping frequencies are popular with parametric eq’s which typically have a bandwidth control, but overlapping is not necessary for stepped frequency type of eq. When you overlap with a stepped eq, you force each band to have a wider range of frequencies than you really want. What if you want to adjust a siblance at 5K6 but still want to boost a little bit at 20Khz- if both of these frequencies are on the same band then you cannot use both. It’s much better for this type of eq to keep the bands separate but have the frequencies side by side.

It did not seem reasonable for this unit to putting 200 or 300hz in the midband and 1k2 in the low frequencies which may work for some things but limit more in other areas making it a heavy trade-off. The E27 does a great job of covering lots of areas between 33Hz – 28kHz

So what you are saying is that transformers are a good thing? What about those ads about "transformerless" circuits?

Transformers are invaluable for audio. They solve many real world problems. Well made transformers are inherently quiet (they are passive) and have a very high common-mode rejection ratio (CMRR- this is how well it rejects noise in a balanced line), they can be run unbalanced without needing any extra help, can handle high levels without severe clipping and they have a great range of characteristic sounds and applications. However, good quality transformer cost a lot more, they are heavy and take up lots of space in circuit boards, and not as readily available. These are not things you could easily clone overseas. Although there are very well made professional transformerless designs, some companies have decided to try and make “transformerless” a thing to desire – this is not a move for better sound but to cut cost in parts.

Much of the older or “vintage” quality gear which contain tubes are sought after because of their great sound but the key factor making those units sound so good isn’t much the tube as it is a fact that older designs have transformers.

But transformers are not made equal, and like many things, you can have good quality, poor quality and everything in between. A well-made transformer, designed and applied specifically for the job it will do, is itself the most valuable component even after many years of use.

The E27 plug-in features a way to remove the characteristic sound of  the transformer out of the audio path. This is used if you prefer less coloration for mastering purposes.

Bell vs Shelf using the two push-buttons at the bottom... Explain.

The Low and High frequencies have a Shelf option which can be used to affect the band before the chosen frequency when using the Low band making it a great adjustable High-Pass Filter, or it could affect the band after the chosen frequency in the High band for larger scale tone shaping. See Graphs.

On the Low band, why does the Shelf start at 63Hz and not at 33Hz?

If you are at 33Hz, the -3db point with the bell is near 15Hz so it’s not really practical to have shelving at 33Hz with this eq. As the graph can also show, having a Shelf at 33Hz would not do any good.