EQ1 seven-band equalizer

Weiss EQ1 – the reference when it comes to digital mastering EQs. Available in four different models, including linear phase and dynamic versions.

The EQ1 is a two channel digital equalizer with seven parametric bands. It has digital inputs/outputs exclusively. The EQ1 is available in four different configurations. All of them work at up to 24 Bit/96 kHz. The basic model is the EQ1-MK2, the linear phase model is the EQ1-LP, the dynamic model the EQ1-DYN. The EQ1-DYN-LP incorporates both LP and DYN versions in one unit. The mode of operation (LP or DYN) can be chosen after power-up. All models are user-upgradeable to any other version.

“The new upgrades to the DS1 and EQ1-LP are remarkable. I think that the double-sampling EQ1-LP is the finest sounding equalizer that has ever been produced, whether analog or digital.”

Alan Silverman, Arf! Digital, USA

Main Features 

Basic EQ1 functions

The basic features are common to all four models, namely the seven identical parametric bands, i.e. all seven bands cover the entire audio frequency range. Each band has Boost/Cut, Frequency and Q/Slope knobs and operates in any of the following modes: High shelving, low shelving, peaking, high cut, low cut, bypass.

 

Controls, display

There are seven times three knobs in order to have “one knob per parameter” operation. The knobs are touch sensitive to switch the LCD to display the parameters of the touched band. The LCD shows the overall frequency response, the detailed parameter values and various status information.

Snapshots, MIDI, metering

Other basic features are an A/B compare memory, a 128 position snapshot bank with two additional banks for back-up (can also be dumped/recovered via MIDI), a peak meter with over indicators, MIDI control for each parameter, an overall bypass switch and an overall gain control, a channel ganging switch.

 

Signal processing, connectivity

The internal processing is done at 88.2 or 96 kHz in a 40 Bit floating-point format. A very low noise filter architecture optimized for audio is used. The digital input/output are in AES/EBU format on XLR connectors. The AES/EBU output can be POW-R dithered to 16, 20 or 24 Bits.

M/S mode

The EQ1 can be switched to M/S mode which is especially useful for the
dynamic model of the EQ1. Also see the article: “Stereo Shuffling: New Approach – Old Technique” by Michael Gerzon. Other specialties are variable slope shelving filters and very high Q (up to 650) peaking filters for notching out offending frequencies.

Reviews and user feedback 

Professional Mastering Engineers

In remastering the Vladimir Horowitz - Live at Carnegie Hall CD set, I used the Weiss EQ1-MK2 consistently, and to great effect. For my purposes, it is one of the essential tools of the trade.”

Jon M. Samuels, Reissue Producer and Engineer, Vladimir Horowitz - Live at Carnegie Hall, USA

 

“The new upgrades to the DS1 and EQ1-LP are remarkable. I think that the double-sampling EQ1-LP is the finest sounding equalizer that has ever been produced, whether analog or digital.”

Alan Silverman, Arf! Digital, USA

 

“My main comment is the sound is very very good, lovely, warm and beautiful, very analog-like. What more could one say?”


Bob Katz, Digital Domain, USA

 

“The Weiss’ EQ1 ergonomics, repeatability, memories, sound, and power are unbeatable.”


Bob Katz, Digital Domain, USA

 

“The EQ1-MK2 is the best sounding Digital EQ1 have ever worked with. It’s so clear, naturally detailed and easy to operate – no wonder it is so highly regarded.”

Maor Appelbaum, Maor Appelbaum Mastering, USA

 

“I love our Weiss EQ1. This would be my first choice if I had to use only one EQ. And the M/S mode in the new software version is very-very useful.”


Chris Hatzistamou, Athens Mastering, Greece

 

“… it was a delight to hear some digital EQ that actually sounded better than anything we’ve had before. I’ve always found that the high end of digital equalizers has never matched the quality of analogue equalizers, but this time the top end was really smooth.”


Bob Ludwig, Gateway Mastering, USA, (One to One Magazine)

 

“The top end just opened up. For the first time I could use digital EQ at high frequencies and get a smooth sound. I even tried 16k and it works. It sounds a lot like the EQP (Pultec analog EQ).”


Eddy Schreyer, Oasis Mastering, USA

 

“The Weiss Double Sampling EQ is probably the best sounding digital equalizer we have ever heard comparing very favorably with our reference analog equalizer, a compliment in itself. It is sonically very smooth, possesses much ‘air’, does not sound pinched when the ‘Q’ is high and is very subtle. A boost or cut of 0.5 dB is clearly audible, something we have never heard in a digital equalizer.” 


Sony Music, USA

 

“… yes, this is one of the few select pieces of kit where after an extended period of use you really feel again and again that it won’t let you down and it +really+ was worth what it set me back. :-) A +really+ nice box indeed. It’s nice to know that there still seems to be a few people around who really cares. My sincere thanx to Daniel Weiss, I really do hope he will sell a bunch of them ….”


Goran Finnberg, The Mastering Room AB, Sweden

 

“This is an email from the engineers at Crystal Mastering to say that we love our new equalizer. The ability to adjust the frequency response of the center and sides is fantastic. The EQ itself also sounds wonderful. Having used analogue EQ for so long, I was truly pleased by what I heard. The only unfortunate aspect of this purchase is that I am under pressure from our chief engineer to purchase more Weiss products. Thanks for such a wonderful toy.” 


From all at Crystal Mastering, Australia

“Anibal Libenson and myself are please to let you know that we have acquired your EQ1-LP and we believe that this has been the very best purchase in EQs that we have ever done.”


Patricio Libenson, Libenson Technical Services, USA

 

“When asking about my gear, I’ve actually had people stop me after mentioning the Weiss EQ and the L2 hardware saying that that’s all they need to hear.”


Dan Shike, Tone and Volume Mastering, USA

 

“The first thing you notice is that you can boost or cut in linear phase far more than in minimum phase without the sound getting problematic, edgy or obviously ‘equalized’. This is clearly not attributable to minor differences in curves. The next thing you notice is that linear phase mode sounds warmer. I attribute this perhaps to the loss of apparent transient response that comes from the pre-echo effect. The wider the Q, the less the problem, as the pre-echo gets shorter and shorter.

 

The next thing I notice is that the high pass in linear phase mode is extremely transparent compared with the minimum phase. Part of it may be due to the curve differences, but you know that you can simulate 24 dB per octave in minimum phase mode by stacking two filters. And even when stacking two filters I find the phase shift in MP mode to be obvious to the ear and affecting more than just the bass.

 

The last thing you notice is that boosting and cutting in LP mode do not move the image forward or backward. You can really warp an image in MP mode, but it stays linear and the depth image remains the same in LP mode.”


Bob Katz, Digital Domain, USA

 

“Wow! It goes without saying that the thing sounds great, but the interface is fantastic! I can tell that it is going to be a real pleasure to work with. I didn’t realize how great the ergonomics were. In a funny coincidence I was able to pick up Joe Doherty’s DS-1 for a song …. I have been dreaming of your stuff for years, and suddenly I am in Weiss heaven!”


Collin Jordan, The Boiler Room, USA

 

“The LP is simply unbelievable at how it sounds and what it can do and the Dyna is one of the most useful digital tools on the planet. Nothing does what that puppy can do! Be prepared to buy as once you hear these you will not want to let them go.”


Larry DeVivo, Silvertone Mastering, USA

 

“I’m loving the Linear Phase upgrade. I’ve really be able to reshape some complicated low end issues with it. One client said; ‘I don’t know what you did to fix it but it’s great and I’m not hearing any side effects.’ Having the linear phase processing in mid/side mode is great as well. You can really get in there and do some surgery! I was telling someone the other day how great the upgradability of your products has been. I bought my EQ1 when it was only 48k capable and wouldn’t upsample! Then to upgrade to the MK2, and now linear phase.”


Bob Boyd, Ambient Digital, USA

 

Technical Data 

Dimensions (cm)

Power

  • Mains voltage: 115 V or 230 V with voltage selector
  • Fuse rating: 500 mA slow blow
  • Power consumption: 40 VA max.

 

Size

  • Depth: 30 cm
  • Width: 43,3 cm (19")
  • Height: 8,8 cm (2HU)

 

AES/EBU Input

  • Sampling frequencies: 44.1 kHz, 48 kHz, 88.2 kHz, 96 kHz
  • Maximum input word-length: 24 Bits
  • Channel Status Data: Input accepts professional or consumer format 
  • Channel Status Data Bits forwarded to AES/EBU output: see table below
  • Connector: XLR female

 

AES/EBU Output

  • Sampling frequencies: 44.1 kHz, 48 kHz, 88.2 kHz, 96 kHz (always the same as the input) 
  • Output word-length: 24 Bits
  • Connector: XLR male

 

AES/EBU Channel Status Data
The EQ1 allows to convert the incoming Channel Status Data as follows:

  • From Consumer to Professional
  • From Professional to Consumer
  • Transparent mode, i.e. Channel Status Data is fed forward to the output without any conversion (one exception, see below)

 

The following tables describe how the output Channel Status Data Bits are generated in the various conversion modes.

 

Output selected: Consumer format, Input: Consumer format:
All Bits fed forward (transparent), except for Byte 1:

  • Bits 0…6: 0000000 (category code general)
  • Bit 7: 1 (original)

 

Output selected: Consumer format. Input: Professional format:
Byte 0:

  • Bit 0: 0 (consumer)
  • Bit 1: 0 (audio)
  • Bit 2: 1 (copy allowed)
  • Bits 3, 4: Pre-emphasis according to input 
  • Bit 5: 0 (two channel mode)
  • Bits 6, 7: 00 (Mode 0)

 

Byte 1:

  • Bits 0…6: 0000000 (category code general)
  • Bit 7: 1 (original)

 

Byte 2:

  • Bits 0, 1, 2, 3: Sampling frequency according to input
  • Bits 4, 5: 00 (accuracy grade II)
  • Bits 6, 7: 00

 

Bytes 3…23: Reserved bytes

 

Output selected: Professional format. Input: Professional format:
All Bits fed forward (transparent), except for Byte 2:

  • Bits 0, 1, 2: 001 (max. sample length = 24 Bit)
  • Bits 3, 4, 5: 101 (24 Bit word-length) 
  • Bits 6, 7: 00

 

Output selected: Professional format. Input: Consumer format:

Byte 0:

  • Bit 0: 1 (professional)
  • Bit 1: 0 (audio)
  • Bits 2, 3, 4: Pre-emphasis according to input
  • Bit 5: 0 (source fs locked)
  • Bits 6, 7: Sampling frequency according to input

 

Byte 1:

  • Bits 0, 1, 2, 3: 0001 (two channel mode)
  • Bits 4, 5, 6, 7: 0000 (no user Bit encoding)

 

Byte 2:

  • Bits 0, 1, 2: 001 (max. sample length = 24 Bit)
  • Bits 3, 4, 5: 101 (24 Bit word-length)
  • Bits 6, 7: 00

 

Bytes 3…12: All Bits 0

Byte 23: CRCC byte

 

Output selected: Transparent. Input: Any format:

  • All Bits fed forward (transparent), except if EQ not bypassed for Byte 2:
  • Bits 0, 1, 2: 001 (max. sample length = 24 Bit)
  • Bits 3, 4, 5: 101 (24 Bit word-length)
  • Bits 6, 7: 00

Overload
Number of consecutive over-samples to cause “over” display: 1…16 selectable

 

Filters
The filter topology used in the EQ1 is a very low noise filter structure for a state of the art performance.

 

Parameter Tables
Center/corner frequencies (Hz):
13.8, 15.4, 17.3, 19.4, 21.8, 24.5, 27.5, 30.9, 34.6, 38.9, 43.7, 49.0, 50.0, 51.9, 55.0, 58.3, 60.0, 61.7, 65.4, 69.3, 73.4, 77.8, 82.4, 87.3, 92.5, 98.0, 100, 104, 110, 117, 120, 123, 131, 139, 147, 150, 156, 165, 175, 180, 185, 196, 200, 208, 220, 233, 240, 247, 250, 262, 277, 294, 300, 311, 330, 349, 360, 370, 392, 415, 440, 466, 494, 523, 554, 587, 622, 659, 698, 740, 784, 831, 880, 932, 988, 1047, 1109, 1175, 1245, 1319, 1397, 1480, 1568, 1661, 1760, 1865, 1976, 2093, 2217, 2349, 2489, 2637, 2794, 2960, 3136, 3322, 3520, 3729, 3951, 4186, 4435, 4699, 4978, 5274, 5588, 5920, 6272, 6645, 7040, 7459, 7902, 8372, 8870, 9397, 9956, 10548, 11175, 11840, 12544, 13290, 14080, 14917, 15804, 16744, 17740, 18795, 19912, 21096

 

Boost/Cut, applicable to shelving and peaking filters (dB):
−39.0, −36.0, −33.0, −30.0, −27.0, −24.0, −21.0, −18.0, −17.0, −16.0, −15.0, −14.0, −13.0, −12.0, −11.5, −11.0, −10.5, −10.0, −9.5, −9.0, −8.5, −8.0, −7.5, −7.0, −6.5, −6.0, −5.5, −5.0, −4.8, −4.5, −4.3, −4.0, −3.8, −3.5, −3.3, − 3.0, −2.9, −2.8, −2.7, −2.6, −2.5, −2.4, −2.3, −2.2, −2.1, −2.0, −1.9, −1.8, −1.7, −1.6, −1.5, −1.4, −1.3, −1.2, −1.1, − 1.0, −0.9, −0.8, −0.7, −0.6, −0.5, −0.4, −0.3, −0.2, −0.1, 0.0, 0.1, 0.2, 0.3, 0.4, 0.5, 0.6, 0.7, 0.8, 0.9, 1.0, 1.1, 1.2, 1.3, 1.4, 1.5, 1.6, 1.7, 1.8, 1.9, 2.0, 2.1, 2.2, 2.3, 2.4, 2.5, 2.6, 2.7, 2.8, 2.9, 3.0, 3.3, 3.5, 3.8, 4.0, 4.3, 4.5, 4.8, 5.0, 5.5, 6.0, 6.5, 7.0, 7.5, 8.0, 8.5, 9.0, 9.5, 10.0, 10.5, 11.0, 11.5, 12.0, 12.5, 13.0, 13.5, 14.0, 14.5, 15.0, 15.5, 16.0, 17.0, 18.0

 

Q, applicable to peaking filters:
0.20, 0.25, 0.30, 0.35, 0.40, 0.45, 0.50, 0.55, 0.60, 0.65, 0.70, 0.75, 0.80, 0.85, 0.90, 0.95, 1.00, 1.05, 1.10, 1.15, 1.20, 1.25, 1.30, 1.35, 1.40, 1.45, 1.50, 1.55, 1.60, 1.65, 1.70, 1.75, 1.80, 1.85, 1.90, 1.95, 2.00, 2.10, 2.20, 2.30, 2.40, 2.50, 2.60, 2.70, 2.80, 2.90, 3.00, 3.10, 3.20, 3.30, 3.40, 3.50, 3.60, 3.70, 3.80, 3.90, 4.00, 4.10, 4.20, 4.30, 4.40, 4.50, 4.60, 4.70, 4.80, 4.90, 5.00, 5.50, 6.00, 6.50, 7.00, 7.50, 8.00, 8.50, 9.00, 9.50, 10.0, 11.0, 12.0, 13.0, 14.0, 15.0, 16.0, 17.0, 18.0, 19.0, 20.0, 22.0, 24.0, 26.0, 28.0, 30.0, 35.0, 40.0, 45.0, 50.0, 55.0, 60.0, 65.0, 70.0, 75.0, 80.0, 85.0, 90.0, 95.0, 100, 110, 120, 130, 140, 150, 160, 170, 180, 190, 200, 220, 240, 260, 280, 300, 350, 400, 450, 500, 550, 600, 650

 

Shape, applicable to shelving filters:
1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19, 20, 21, 22, 23, 24, 25, 26, 27, 28, 29, 30, 31, 32, 33, 34, 35, 36, 37, 38, 39, 40 ,41, 42, 43, 44, 45, 46, 47, 48, 49, 50, 51, 52, 53, 54, 55, 56, 57, 58, 59, 60, 61, 62, 63, 64, 65, 66, 67, 68, 69, 70, 71, 72, 73, 74, 75, 76, 77, 78, 79, 80, 81, 82, 83, 84, 85, 86, 87, 88, 89, 90, 91, 92, 93, 94, 95, 96, 97, 98, 99, 100, 101, 102, 103, 104, 105, 106, 107, 108, 109, 110, 111, 112, 113, 114, 115, 116, 117, 118, 119, 120, 121, 122, 123, 124, 125, 126, 127, 128

 

Threshold, applicable to dynamic peaking filters (dB):
0, −1, −2, −3, −4, −5, −6, −7, −8, −9, −10, −11, −12, −13, −14, −15, −16, −17, −18, −19, −20, −21, −22, −23, −24, − 25, −26, −27, −28, −29, −30, −31, −32, −33, −34, −35, −36, −37, −38, −39, −40, −41, −42, −43, −44, −45, −46, −47, −48, −49, −50, −51, −52, −53, −54, −55, −56, −57, −58, −59, −60

 

Slope, applicable to cut filters:
0 dB/octave, 6 dB/octave, 12 dB/octave

 

Overall Gain (dB):
off, −92.0, −89.0, −86.0, −83.0, −80.0, −77.0, −74.0, −71.0, −68.0, −65.0, −62.0, −59.0, −56.0, −53.0, −50.0, − 48.0, −46.0, −44.0, −42.0, −40.0, −39.0, −38.0, −37.0, −36.0, −35.0, −34.0, −33.0, −32.0, −30.0, −29.5, −29.0, − 28.5, −28.0, −27.5, −27.0, −26.5, −26.0, −25.5, −25.0, −24.5, −24.0, −23.5, −23.0, −22.5, −22.0, −21.5, −21.0, − 20.5, −20.0, −19.5, −19.0, −18.5, −18.0, −17.5, −17.0, −16.5, −16.0, −15.5, −15.0, −14.5, −14.0, −13.5, −13.0, − 12.5, −12.0, −11.5, −11.0, −10.5, −10.0, −9.5, −9.0, −8.5, −8.0, −7.5, −7.0, −6.5, −6.0, −5.8, −5.6, −5.4, −5.2, − 5.0, −4.8, −4.6, −4.4, −4.2, −4.0, −3.8, −3.6, −3.4, −3.2, −3.0, −2.8, −2.6, −2.4, −2.2, −2.0, −1.8, −1.6, −1.4, −1.2, − 1.0, −0.8, −0.6, −0.4, −0.2, 0.0, 0.5, 1.0, 1.5, 2.0, 2.5, 3.0, 3.5, 4.0, 4.5, 5.0, 5.5, 6.0, 6.5, 7.0, 7.5, 8.0, 8.5, 9.0, 9.5, 10.0

Dither:
Dithering algorithms are implemented using the POW-R set of algorithms, i.e. POW-R #1, POW-R #2, POW-R #3

 

MIDI Remote Control Protocol
All band parameters plus the controls parameters are remote controllable. Each parameter has its corresponding MIDI controller number. According to the different parameters, the controllers are limited in their range. Invalid values are replaced by the maximum allowable values. Details can be found in the EQ1 manuals.

Applications 

The EQ1 can be inserted into any digital audio chain with sampling rates between 44.1 and 96 kHz. The synchronization is done via the AES/EBU input signal.

 

EQ1-MK2
The EQ1-MK2 is the basic model with minimum phase type filters.

 

EQ1-LP, the EQ1-MK2 with linear phase response
The EQ1-LP has the same parameter set and features as the EQ1-MK2. In addition it can be switched between minimum and linear phase behavior. Linear phase means that the delay introduced by processing is constant across the whole spectrum, unconstrained by the EQ settings. The sound, or character, of an equalizer has been said to be influenced by phase response as for example John Watkinson mentioned in Studio Sound magazine 9/97: “… much of the audible difference between EQs comes down to the phase response.” The EQ1-LP is therefore the ideal tool for corrective amplitude adjustment, without the unwanted phase distortion added by standard equalizers.

 

EQ1-DYN, the EQ1-MK2 with four dynamic bands
The EQ1-DYN features four freely adjustable dynamic bands, and additionally three linear bands per channel. Setting up the dynamic bands is as easy as setting a linear band. There is just one additional parameter to be adjusted by the user, the threshold control. This makes multi-band dynamic control as easy and as versatile as adjusting a parametric equalizer. The dynamic EQ can be used as a de-esser or to give the bass an extra punch etc..

 

Bands 1, 2, 5 and 6 are the dynamic bands (each individually switchable to linear) and bands 3, 4 and 7 are ordinary linear bands. A dynamic band operates similar to a compressor, with two additional features:

 

1) The band is sensitive to signal level in its frequency range only. So when applying dynamic bass EQ, only the bass-band of the program affects the dynamic behavior. There is no cross-modulation from other bands.

 

2) The gain is only applied to certain frequencies, and not across the whole audio band.

 

3) Other modes (low-cut, high-cut, low-shelving, high-shelving) are linear (no automatic boost/cut adjustment), and behave exactly the same as in the EQ1-MK2.

 

The reason for choosing exactly bands 1, 2, 5 and 6 is the following: As the name implies, a dynamic band is sensitive to the level of the input signal. Sometimes it is desirable to first add some EQ, and afterwards dynamically add some more. Or vice versa, first do some dynamic corrections and afterwards add overall EQ, including in the corrected band. Because the EQ bands are connected in series, this is only possible if there are linear bands before and after the dynamic bands.

EQ1-DYN-LP, Dynamic and Linear Phase EQ in a single unit
The EQ1-DYN-LP contains both the Dynamic and the Linear Phase EQ programs. After power-up of the unit, the user can chose between Dynamic (DYN) and Linear Phase (LP) modes. The workspace storage, the snapshots and the snapshot backups are fully independent between the DYN and LP parts of the unit. This means that all setup data are retained in any case.

FAQ 

For Frequently Asked Questions and discussions about this and other products our new Forum will be available soon.

 

Thank you for your patience.

 

 

 

 

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