Bel Canto Bass EQ: No Going Back

 A very useful features embedded in the BLACK system architecture that is found in our E1X, BLACK EX and BLACK System Components is our DSP based BASS EQ control. This control uses precision DSP algorithms that have nothing in common with the crude +/-15dB analog Bass and Treble controls of yesteryear that have been justifiably driven from the audiophile consciousness. Our spectral controls use gentle 64bit, double precision, DSP based IIR filters embedded in the BLACK system architecture and mimic the phase and frequency response of second order analog filters. Our unique system architecture includes these features with no added A/D or D/A stages, no added analog components to create noise or distortion or FIR filter time domain anomalies to compromise the sonic quality of the system.

The Bass EQ function is great for taming overly active speakers or rooms or for filling a large space that would otherwise lack bass energy. For example, if the mid-bass is too present this can lead to veiling of mid-range information. With the +/-3dB Bass EQ function you can easily optimize bass balance in the room. The transfer characteristic of the BASS EQ control is shown below:

bass control graphic 2017
BASS EQ Control Characteristics

It operates as a shelf below 200Hz and provides precision 0.6dB steps over a +/-3dB range. I use this in my personal system in the +3 position to add 1.8dB of boost to my TAD TD-2404 Studio Monitors. These do not have the typical mid-bass bump of many high-end speakers and they are loaded into a very large volume of space so this 1.8dB is perfect to get the overall sonic balance just right. I leave this control fixed for all music and occasionally use the TILT for specific recordings, as needed. No compromise here and complete repeatability. It is interesting that a setting of 2 or 4 does not quite cut it, 3 is the Goldilocks setting for my system and room, demonstrating that the 0.6dB setting offers just enough resolution to hit the mark, without driving you crazy with too many discrete steps.

I was recently involved in optimizing system settings for an ACI600 based system using more typical high -end speakers with the mid-bass (circa 100Hz) bump in a much smaller space. There was just too much bass energy, causing mid-band veiling. We set the BASS EQ to -2, trimming 1.2dB off below 200Hz and the system opened right up, without giving any feeling that the low bass energy was lacking.

 Living with these filter options to optimize the in-room listening experience I would be loathe to have a system that does not offer this kind of capability. There is no sonic compromise with this control so it can be used to achieve the goal of optimizing the in-room experience without compromising any aspect of musical playback. These embedded DSP based IIR controls add no noise or distortion like old-school analog based EQ or any time domain distortions introduced by FIR room correction filters. Beware, once you experience the system optimizing powers of these controls there is no going back!

DACs and High Dynamic Resolution

 “What DAC do you use?” Many times, I have heard this question, as if the answer will somehow reveal a magic door into Bel Canto’s musical soul. The simple answer, “for the past 15 years or so our ultimate DAC choice has been the PCM1792A”, doesn’t really explain much except that this venerable DAC device continues to reveal depths of performance that I would not have guessed possible those many years ago. Fifteen years later it still offers numbers that are state of the art, 130dB dynamic range, distortion below 0.001% and a current output that biases the external analog stages with a constant current for best analog linearity, thermal stability and transient dynamic range. I have tested many newer DAC devices and have yet to find anything that betters the 1792, including current in vogue discrete multi-bit designs and variations on integrated and discrete delta-sigma or single-bit DACs. Our many years of using this part in our products have led us to the unique High Dynamic Resolution DAC solution embodied by our BLACK System and extending to both BLACK EX and the new E1X lines.

Bel Canto’s unique system and circuit architecture optimizes true system dynamic range through the use of our Asynchronous Multi-Input Processor front end to receive and condition both analog and digital sources, the AMIP passes this optimized signal on to our High Dynamic Resolution II DAC core that extracts full analog performance from the DAC stage by placing it within a highly optimized environment. The ultimate system performance preserves the original recorded information, insuring low dynamic noise and distortion and High Dynamic Resolution at the loudspeaker. We have found that this architecture preserves recorded information better than traditional systems where there is a source, a DAC or CD player or phono preamp, going to an analog preamplifier then on to an analog power amplifier. We shorten this old, traditional approach to the system signal chain, eliminating numerous analog stages: switches, controls, power supplies, and cables. The resulting Bel Canto AMIP/HDRII based system brings the listener closer to the original recorded event and the music’s emotional impact.

This performance capability was brought home recently when I was comparing some of the excellent Cardas Clear power cord line. The added noise rejection ability of the top power cord was made remarkably apparent listening to, of all things, an MQA remaster of the extended version of The Doors “Light My Fire”. With the already excellent Clear power cords used for the MPS1 units in my system replaced by the Clear Beyond XL cords the presence of the band in the room was even more palpable and the strong emotion that Jim Morrison exudes was even more evident. My wife commented that the lesser cables did not quite bring the raw emotional power that this track achieves when reproduced with the lower dynamic noise floor that the XL cables bring to the system. This clearly demonstrated the increased level of involvement that High Dynamic Resolution and a reduced system noise floor can bring to the audio experience.

By getting the best from the PCM1792A DAC and exploring fundamental system architecture innovations as well as improvements to the system environment we achieve a level of musical communication and involvement that only a High Dynamic Resolution system can provide.

Round and Round

Seems like I have forever been on the Audio Cable Merry-Go-Round. This was brought to a head recently when I was over at a good friend’s place listening to music. I helped him put this system together using our e.One C5i Integrated amp with the e.One Stream unit to stream Tidal music into a pair of the new JBL L100 Classic speakers and some USA made audio cables that I have used at the office. I was very pleased that this system sounded great right out of the box with little time on either the speakers or the electronics. We listened to a selection of Jazz, Classical and some Rock that evening and I thought to myself that it sounded good enough that I could live happily with the sound. Very dynamic, very present, and well balanced. The kind of sound where a solo piano heard from the other room could fool you into thinking someone was playing there. Over the past year we have had several occasions for an evening of music. Each time I came away thinking, wow what a great music system.

After these experiences I decided to pull out a pair of top line speaker cables from the same manufacturer as the cables in my friend’s system and put them back in my system. I had been recently using a hybrid combination of solid silver ribbon for the HF above 650Hz and a shotgun pair of medium gauge solid copper for the LF below 650Hz between the BLACK MPS1 units and the TAD2404 horn monitors. A combination that I have found to work well, better than some very highly pedigreed audiophile cables that I have had in and out of my system over the years.

Out with the funky hybrid cables, in with the old faithful that I had written off. Revelation. That evening I played some old favorites and I loved the rich, natural balance, the saturated tonal colors, and realistic dynamics. You could say that some ‘transparency’ was lost but the lack of any spotlighting of any frequency band made the sound more engaging and very musical. My wife was listening from the other room and commented on how good the music was sounding. I had not told her that I had changed anything.

A great recording from Ahmad Jamal, Blue Moon from the same album in full resolution on Qobuz, presents a concrete example of the impact of the good balance. This is an intense re-imagining of this classic tune. With the new/old cables the underlying harmonic and melodic structure of this famous tune remains present and obvious throughout Ahmad’s dynamic excursions and slashing attacks. The complex rhythmic support is woven deep into the tune’s fabric. With other cables the spotlighting effects could easily confuse the brain, making it difficult to hear the underpinnings of the original tune. It was always compelling but with these well-balanced cables the reinterpretation is clear and more meaningful.

The Cable Merry-Go-Round is over for me. I am enjoying music with these cables.

The engineer in me asks what makes these cables so good and why did it take me over 10 years to get back to them?

I have some thoughts about this:

  1. My system has evolved greatly over these years-the BLACK System is much more open and detailed, and natural sounding. Even the latest C5i/Stream combo with the L100 speakers are better in many ways than the older system I was using when first listening to these cables.
  2. These cables use solid engineering and technology; a modified Litz wire construction using specially processed high purity copper. Litz wire is designed to provide very uniform power transfer for signals below 1MHz, ideal for audio application. The custom design of this Litz wire would likely reduce standard Litz wire’s tendency to spotlight certain frequency bands. My engineer brain likes this kind of no-nonsense approach with clear engineering goals and application.
  3. I needed to ride the Merry-Go-Round for a while, living with alternative designs and technologies. My personal audio goals have also matured along with my system. The enjoyment of the musical experience gaining precedence over a ‘transparency at all cost’ kind of goal set. With the improvement of my system I find that these older cables do transfer the information in the signal but in a more natural and engaging manner than many other cable options.

Think about your personal goals with your audio system when putting your system together. I am happy to confirm that good materials, good design, and good engineering ultimately rule the day in audio cables, audio electronics and speakers. This makes both my engineer left brain and my music loving right brain happy.

Turkeys Can Fly

Recently an owner of REF600M amplifiers asked if they can be bridged. I told him that this was not an option and wondered why he was asking, given that they develop more than 300 Watts into 8 ohms and 600 into 4 and still more into 2ohm loads. He replied a bit sheepishly with a funny anecdote. He and a friend went to his friend’s mother’s house to work on something and they found her struggling in her yard. His friend asked his Mother what she was doing, she said that she was trying to put up a fence to keep the wild turkeys out. His friend pointed out, “You do know that turkeys can fly Mom?”

This anecdote reminded me of the general confusion around networked audio streaming which is sometimes regarded as the poor cousin in music delivery. My experience with networked audio leads me to a very different conclusion. I find that using the Ethernet or WiFi connection to stream from either a local server with your personal FLAC or ALAC library or listening to Tidal or Qobuz results in a superior musical experience, equal of any digital source. Bel Canto’s bit perfect, asynchronous Ethernet interface and our custom MQA filters for MQA material and MQA based filters for PCM material play no small part in my personal streaming experience, of course. When you add in the remarkable sonic advantages of MQA from Tidal or high res FLAC from Qobuz and factor in the enormous musical libraries it is obvious that not only is the sound excellent but it opens up a compelling new way to experience music in your home.

This was underlined in an eclectic musical journey at home. We started with a CD from my personal library of a Barney Kessell release from 1959:

Picture 1 of 1

I heard a cut from this disc on the VTuner internet radio station FIP. This station is part of Radio France and has a wonderfully eclectic selection of great music. Now neither Tidal nor Qobuz has this CD so I purchased a copy and ripped it to my personal collection. We listened through the disc and it made me think of a remarkable Charlie Byrd remastered LP from Analogue Productions. This LP sounds extremely natural and musical. Showcasing the best of the venerable LP.


We listened to several cuts and I pulled out an old Paris flea market LP find from some 30 years ago, Nina Simone’s Bethlehem tour de force “Baby Just Cares for Me” compilation.

Having enjoyed several cuts on both sides I was curious how the CD remastering of a couple of cuts would sound streaming from Tidal or Qobuz as this well listened to LP was showing its age- though the music remains as compelling as ever. Finding the tracks proved simple enough and we were treated to a closer reading of the original master tape without the attendant LP artifacts and I found myself drawn even deeper into the musical experience of the 5 ½ minute instrumental “Good Bait”, experiencing the quality of the piano and its response to Nina’s very dynamic playing. Then on the final cut of the evening, “Plain Gold Ring” I found myself literally getting goose bumps in response to her powerful vocals on this emotional track.

Explore your own musical adventures without concern for specific formats or dogma surrounding internet radio, FLAC or MQA streaming, LP or CD playback. Just sit back and enjoy the trip!

DO check out FIP on VTuner as this is a great way to discover new and rediscover old music and feed your musical explorations. There is a FIP app where you can follow what the VTuner station is playing in real time, then you can look for a track on Qobuz or Tidal in CD or better quality-or purchase a new LP or CD to add to your collection.

The Genesis of BLACK

In 2010 I put together a high-quality field recording system starting with a pair of remarkable omni microphones developed by the late Joe Grado. His HMP-1 microphone is likely the most natural sounding mic ever developed for acoustic recording. I paired it with a Sound Devices 722 stereo digital recorder and started making high resolution 24/96 recordings of acoustical music in Antonello Hall at the MacPhail Center for Music in downtown Minneapolis. I have made dozens of recordings over the years and always monitor the live event using a pair of closed back Denon headphones direct from the 722. These acoustic recording experiences have taught me much about listening. How to recognize natural timbres, dynamic musical cues and the presence of low distortion and deep information retrieval in the playback chain. It also revealed how much was missing when listening through my reference system at the time. A system with numerous boxes, a classic analog and digital playback system architecture with many power cords and analog and digital interconnects. A rather long chain with the chance for signal loss and introduction of added noise and distortion at each link in the chain. A typical high-end audio system.

When we decided that Bel Canto needed a flagship or halo product design that would go well beyond any of our current products I was inspired by my recording experiences to conceive of a system that would introduce minimal signal loss, with extremely low distortion and noise and maximum dynamic range. This approach would ensure that I could hear everything that I expected from my recordings. This led me to conceive of a system architecture that is well outside the traditional high-end audio system paradigm. My concept of the original BLACK System began with a thought experiment: how to best combine edge of the art analog and digital design and architectural choices to achieve an audio system that would preserve all of the original recorded information that was presented to it from any source. A simple, yet demanding goal. 

The BLACK System concept starts with the ASC1 and subsequently the ASC2 controller/processor that receives the source information. Digital source inputs are processed to remove jitter artifacts, analog inputs are immediately converted with a high dynamic range converter.  In this way all signal inputs flow through the same optimized lossless signal path through the ASC2 Controller to the MPS1 Power Converters and out to the loudspeaker terminals. The MPS1 units are mono Power Converters that contain a minimalist, 3-stage analog signal path from DAC through to the 1200 W capable power outputs. Each MPS1 receives the signal from the ASC2 through high speed fiberoptic connections guaranteeing that no noise is produced from the fiber interconnects nor are they subject to electrical noise from any outside source. The fiber also provides complete galvanic isolation between the 3 units in the BLACK System, this prevents any possibility of ground loops or other noise coupling. The critical analog electronics in the MPS1 are custom class A discrete circuits using the best parts. These circuits are cocooned within an optimum environment. The cocoon is both mechanical, result of the massive billet machined chassis and damped construction, and electrical, result of the galvanic isolation and multi-stage power supply regulation. The BLACK System architecture and design delivers an ultra-wide system dynamic range of 128dB at the loudspeaker outputs. The sonic and musical results can be described simply as utter musicality, revealing the true sound of any musical source recording that you send through the BLACK System. 

I will expand on further evolution of the BLACK System and my personal experiences living with it in future installments.

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