MODX+: Glad that’s over!

Yamaha launched its MODX+ keyboards today. The MODX+ has a few modest improvements over the MODX (Mk1):

  • 1.75GB user waveform memory
  • Rubberized pitch and mod wheels
  • New livery (black end-cheeks)
  • 128 tone FM-X polyphony (maximum)

Seamless Sound Switching (SSS) is the same as MODX (limited to 4-part Performances). There are a few on-line videos that are incorrect. The USB audio spec has not changed either.

In case you missed it, Yamaha have a MODX+ Early Adopter Promo Rebate. Register your MODX+ and receive a free FC7 expression pedal and FC5 foot switch. The promotion ends 31 December 2022. That should take some of the sting out of the new prices: $1,499 MAP for the MODX6+ versus $1,399 for the MODX (Mk1). Look for a bundled gig bag, too.

Yamaha are promoting a downloadable Bösendorfer piano. Gotta fill up that expansion memory! Look for new additions to the Montage/MODX+ library in the future. Yamaha IdeaScale participants previewed a new CP-90 piano currently in development. Big multi-samples to drive MODX+ sales.

Anticipatory discussion was filled with wishful thinking and speculation concerning the addition of a second SWP70 tone generator chip and possibly AN-X™ virtual analog synthesis. Judging from the boost in FM-X polyphony, the MODX+ quite likely got the second SWP70.

Speculation about AN-X borders on fantasy. It is based on the premise that an SWP70 is even capable of virtual analog synthesis. Other than Yamaha, does anyone really know what is inside of an SWP70 tone generator?. I don’t.

Adding further doubt for the wet-blanket brigade, I offer the design decisions surrounding the Reface series. The Reface YC and CP are genetic sisters. Both are based on AWM2, both using the SWX08 processor with integrated AWM2 tone generation. Why then, did Yamaha deploy the SSP2 digital signal processor in the Reface CS? Surely, it would have been more cost effective to share the same logic board as Reface YC and CP. Thus, I have my doubts unless SWP70 has some hidden, yet-to-be revealed functional capabilities. Yamaha have the new SSP3 to play with, too.

Given the limitations of the Montage/MODX user interface, including relatively few front panel controls, AN-X on Montage/MODX+ is just putting a bag on the side of a fine product. [Apologies to Tracy Kidder.]

So, I don’t think Yamaha is finished with announcements. There are still CK61™ and CK88™ to account for. Marketing 101 says “Don’t muddy the waters with multiple product launches in a given lane.” Plus, Yamaha marketing is not that big and poor Blake needs to flog the MODX+ while it’s hot. Stay tuned, boys and girls.

Punters are trying to justify the small price increase in terms of component count, etc. Yamaha priced MODX+. Done. If they don’t shift boxes, Yamaha will drop the regional MAP. Currency fluctuation may have more to do with variations in price than component count. Unfortunately, the suits often win.

As to price, one more observation. MODX and MODX+ have crashed the psychological $1,000 USD barrier. Smash it. The MX series is the only sub-$1000 offering. (Reface don’t count with its mini-keys.) There is a big gap between MX and MODX. I don’t think Yamaha can raise prices on the current MX, so maybe something else is coming?

Copyright © 2022 Paul J. Drongowski

Yamaha MODX+ madness

Thanks to a few pages posted from the Yamaha MODX+ user manual, the new MODX+ is a bit of a nothing-burger — a product spiff. The MODX+ got a few bumps over MODX (Mark 1): more expansion memory (1.75GB), FM-X polyphony on-par with Montage (128), and a way to add rhythm patterns:

Also, the MODX+ has a new feature for instantly adding rhythm patterns so that the players can take their music creation forward with dynamic rhythm parts. With this feature, creating rhythmic changes in the “Motion Controls” is easier than ever! [Yamaha]

Just enough to keep MODX+ competitive in its price bracket. The bump in FM-X polyphony indicates the likely addition of a second SWP70 tone generator IC.

I suspect Yamaha will use new downloadable libraries to drive a few pack-rat punters to upgrade to MODX+. Recently, IdeaScale participants had a chance to preview a new CP-80 voice (and waveforms). Yamaha were soliciting opinions as to which voices/waveforms had the most sonic appeal. A flood of must-have content might create demand among current MODX (Mark 1) players, making that 1.75GB a necessity.

The forums are filled with speculation about AN-X™. Again, a lot of wishful thinking about AN-X coming to Montage and/or MODX+. Only Yamaha know for sure.

As yet, however, no one has solved the mystery of the other registered trademarks: CK61™ and CK88™.

Yamaha have moved on from the SSP2 signal processing chip to the SSP3. The SSP3 first appeared in the Yamaha AXR4U and Steinberg UR44C audio interfaces. Yamaha move ahead like a shark and the SSP2 is deprecated for new designs. In fact, the MODX+ refresh likely includes the SSP3 as SSP2 production inventories must be low or exhausted.

That turns my attention to the Reface DX and Reface CS. The Reface DX and CS are sisters, sharing the same internal design modulo screen interface and front panel gizmos. Both are based on SSP2 and, thus, both may be in need of a refresh — or replacement. The SSP2 signal processor provides the FM and VA synthesis horsepower.

Simply put, will CK61 and CK88 replace the Reface DX and CS? Will the CK61 and CK88 be the AN-X machine? How will Yamaha monetize AN-X? When it comes to business, Yamaha are not fools. Never sell one model when two will do as well! Ka-ching. 🙂

On a personal note, I started this site to inform players about music technology and what’s inside the tin. It’s gratifying to read the forums and see how much this site has influenced discussion, especially discussion about Yamaha products. Thank you for reading and please keep coming back! — pj

A few handy links:

Copyright © 2022 Paul J. Drongowski

Is MODX+ on the way?

[Updated 18 August 2022.] Rumors are circulating about Yamaha MODX — either replacement or refresh.

Now pictures of a misdelivered “MODX8+” have appeared. Naturally, one asks “fake or real?” Cosmetically, the only external differences are:

  • A different product model legend on the right side of the top panel, e.g., “MODX8+ Music Synthesizer”.
  • Black plastic end-cheeks instead of grey.

The MODX8+ was shipped mistakenly to a customer. Support anticipates release in the Sepember or October timeframe.

MODX8+ real or fake?

The new livery reminds me of the Yamaha MX series V2 spiff. It was somewhat difficult for a customer to identify an MX V1 vs. an MX V2. The new MODX+ legend makes the mark 2 clearly distinguishable. No word about enhanced features or sound set. One must also ask if the Montage will get a spiff, too?

I’m going out on a limb — real.

Update: MODX+ discussion is rampant in the forums. Here are a few quick comments, corrections and a request.

SWP70 is an integrated circuit designed by Yamaha. It is manufactured by a partner fab. Yamaha is fab-less. Yamaha transferred its semiconductor manufacturing subsidiary to Phenitec Semiconductor in 2014. It takes a lot of money to build and maintain semiconductor fabrication factories — a money losing proposition for Yamaha (or my old employer, AMD, for that matter). Yamaha remains a manufacturing powerhouse at the board level and sells its own line of PCB assembly equipment.

SWP70 processors are manufactured in batches based on Yamaha’s estimated need. Depending upon the portability of the SWP70 design, Yamaha may turn to multiple alternative partners for fab. “Portability”, in this sense, means how easily the design can be re-targeted for a specific fabrication process.

Generally, Yamaha has done a good job exploiting commodity components. The SWP70 uses ONFI-compatible NAND flash and RAM. The MODX and Montage host processors are high-volume, embedded ARM microcomputers. Although Yamaha has preferred suppliers for NAND flash and RAM (e.g., Cypress/Spansion, Winbond), these are commodity parts and are available from many suppliers. Commodity components are probably not a pressure point.

As I’ve said before, Yamaha have just a few critical external supply vulnerabilities. Aside from fab capacity, SWP70s or other Yamaha proprietary processors are likely not the issue here. When it comes to DACs and ADCs, however, Yamaha is very reliant on Asahi Kasei Microdevices (AKM). AKM is still trying to recover from its factory fire. The AKM supply shortage has put Yamaha and many other vendors on the back foot.

Yamaha have the right to substitute components. Every manual has the following disclaimer:

Specifications and descriptions in this owner’s manual are for information purposes only. Yamaha Corp. reserves the right to change or modify products or specifications at any time without prior notice. Since specifications, equipment or options may not be the same in every locale, please check with your Yamaha dealer. Visit the web page for information on the latest Owner’s manual.

Of course, this could mean substituting for AKM devices. DACs and ADCs communicate via the I2S digital audio interface format. If Yamaha did substitute — speculation — would we hear an audible change?

Much speculation surrounds the second, unpopulated SWP70 position (TG slave) on the original MODX printed circuit board. The TG slave has an associated open position for DSP RAM only. Thus, if Yamaha choose to use the same board and to populate the open positions, these changes would bring MODX+ up to the same polyphony spec and tone generation horsepower as the current Montage. Montage would still have the advantage in digital audio routing and processing (including audio channels over USB). The original MODX board does not have provisions for upgraded audio channels.

A product spin is needed when a Yamaha proprietary component is obsoleted and out of inventory. Such may be the case with the venerable SSP2 — a workhorse in many Yamaha products including mixers, Reface CS and Reface DX. Yamaha and Steinberg have moved on to the SSP3.

Finally, a request. Please do not publicly reveal your source of leaks. Yamaha are incredibly paranoid, exceeded only by Apple and Sony in this regard. First, leaks get real people in trouble. Second, Yamaha learn from their mistakes. Protect your sources and methods!

Copyright © 2022 Paul J. Drongowski

You spin me right round

Spot product shortages have sparked speculation about discontinued products, new products, etc. Given the human propensity to look for and find patterns, it’s no wonder that conspiracy theories take hold!

The on-line inventory picture is mixed. Some retailers show Yamaha Montage/MODX, for example, in stock, some show them out of stock pending September availability and, in one case, discontinued.

Random “discontinued” tags seem to come and go. A month ago, the Yamaha Canada site marked the MX as discontinued. Now the marker is gone. Better indicators are blow-out pricing to move stock or a Yamaha spiff incentive to move old stock. So far, I haven’t seen any clearance pricing or promotions.

Yamaha’s mid- to upper-end keyboard products have a vulnerable supply dependency on Asahi Kasei Microdevices (AKM) DACs and ADCs. The AKM factory fire was worse than originally thought and production is still not back on-line. Renesas has offered to manufacture AKM devices. The Yamaha UK site has the disclaimer, “Due to the difficulty in procuring semiconductors and procuring parts worldwide, some of our product area deliveries may be delayed. Thank you for your understanding.”

AKM aren’t very public about their recovery and certainly haven’t released a public roadmap. A recent press release for VELVET SOUND DACs and ADCs mentions sampling (no pun intended) in January 2022 with “mass production scheduled for the third quarter of 2022.” Given that Toyota is a top AKM customer, who wins, Toyota or Yamaha? 😉

The AKM shortage inspires other conspiracy theories, too. Theory #1: Yamaha are using non-AKM DACs and ADCs in Montage — the analog/jack (AJK) board was redesigned or manufactured with inferior non-AKM devices. Theory #2: MODX is suspended in order to give preference to and ship the wider-margin Montage. Someone went so far as to ask about replacement DACs in Montage and got the usual non-response from Yamaha. (What did they expect?)

Some of the Yamaha boards use Yamaha proprietary ICs, e.g., SWL, SWX, or SSP2 processors, creating a different supply dependency. When production inventory is exhausted, Yamaha need to re-spin end product to use a newer part. The July 2016 MX refresh is one interesting example. I believe that was the case with the MX refresh.

I haven’t seen a new version of the heavy weight SWP70 tone generator. However, Yamaha have updated both the SWX and SSP lines:

  • The SWX08 is replaced by the SWX09.
  • The SSP3 — now appearing in Steinberg and Yamaha pro audio products — will likely replace the SSP2.

The SWX update would affect mid-range keyboards, notably the Yamaha Reface CP and YC. The SSP update would affect Montage, MODX, and Reface CS and DX.

Are new product spins in the works? Something is coming (eventually) given the CK61™/CK88™ and AN-X™ trademarks. Once again, only Yamaha really knows. 🙂

Copyright © 2022 Paul J. Drongowski

Guess again: AN-X ™

Various forums are buzzing about Yamaha’s latest trademark application: AN-X™. The application was filed 9 June 2022 and must go through several steps before approval.

Like “CK61™” and “CK88™”, the primary class is “Musical Instruments” and the trademark registration is “intended to cover the categories of musical instruments, namely, electronic musical keyboards, electronic pianos, music synthesizers.”

Although Yamaha submitted a drawing (below), the “mark is presented in standard character format without claim to any particular font style, size or color.” So, keep your fingers offa those characters! 🙂

Yamaha trademark application pending

Update: Yamaha have filed for a stylized (figurative) trademark in the European Union. See image below.

Yamaha ANX trademark (European Union, filing: 018741845)

Of course, everyone is deconstructing the proposed mark. “AN” is known as Yamaha’s Analog Physical Modeling Synthesis as embodied in products like the AN200 Desktop Control Synthesizer. I’ve still got my AN200 and it’s a keeper. The AN200 consists of an SWX00B host processor and a PLG150-AN daugherboard. The PLG150-AN itself has a Renesas H8/300H 16-bit microcontroller and two Yamaha custom integrated circuits: VOP3 and MDSP. The custom circuits implement the VA synthesis and digital effects.

Yamaha AN200 analog physical modeling synthesis

It’s worth mentioning that VOP3 appears in the Yamaha FS1r — the inspiration for today’s FM-X. The FS1r does both 8-op FM and Formant Shaping Synthesis. Internally, two custom FS1-AB integrated circuits perform FM and formant shaping synthesis. Two VOP3 integrated circuits implement the filters (the first VOP3) and effects (the second VOP3).

Yep, I’ve mused about adding VA synthesis to Montage before and was skeptical about adding it to the existing SWP70-based Montage pipeline. I remain doubtful about adding VA synthesis to the existing Montage/MODX platform.

It’s worth noting, again, that Yamaha have never published nor described the actual data processing pipeline and signal paths within the SWP70 tone generator. I don’t have any formal relationship with Yamaha nor does Yamaha engineering ring me up regarding the internal details of their tone generation hardware. 😉 Do I have a right to change my mind in light of new information and analysis? Yes. Do I hope for a surprise from Yamaha? Yes.

The question is whether the SWP70 is capable of subsuming VOP3-like DSP functionality for VA synthesis. It’s how the YC series implements its Virtual Circuitry Modeling (VCM) organ engine. Clearly, if you can model drawbars, you can model an analog oscillator. Lest anyone forget, the Montage V3.0 upgrade (MODX V2.0) added the VCM Mini Filter, VCM Mini Booster and Wave Folder DSP effects.

An earlier version of this port stated the YC series uses modeled tonewheels. Further analysis makes me believe otherwise.

As to filtering, what is a hardware or software digital filter other than a mathematical model of an analog filter — even if its cold and heartless? What is a digital amplitude envelope other than a model of an analog envelope generator and VCA? Distinction due to implementation technology is nearly moot; it comes down to the characteristics of the particular models.

What does all this portend for the future? If I were Yamaha and I could add VA to the Montage (MODX) platform, I would sell it as an upgrade. Many people want VA on Montage and there is money to be made.

I’m willing to go a step further. Yamaha could and should offer a VCM organ upgrade, too. The SWP70 can support it. I’ll put money where my mouth is — I will pay real money for a YC upgrade on MODX (Montage). BTW, there’s no technical reason to not offer the FM-based YC organs on MODX/Montage already — it’s FM-X, after all.

Now, what are “CK61” and “CK88”? 🙂

Copyright © 2022 Paul J. Drongowski

Critique: Genos™ drawbar organ

I like the Korg Module Pro “GospelOrgan” patch, so I tried to create a sound-alike voice on Yamaha Genos. Genos and MODX share the same waveforms and DSP effects, and I may port the result to MODX, too.

The experience recalled my previous misgivings about the rotary speaker simulation and limitations of the Genos DSP effect implementation. I will amplify those comments here.

Mid- to upper-level Yamaha arranger workstation have long had a drawbar organ feature which Yamaha calls “Organ Flutes.” This feature dates back to 1999, appearing in the PSR-9000 keyboard. Although a few details have changed over the years, Yamaha has not substantially overhauled Organ Flutes. It’s time, Yamaha — the world has moved on. I’d love to see the new YC organ technology in Genos. It’s the flagship of the arranger line and YC organs would definitely differentiate Genos from its lower-cost brethren.

Yamaha Organ Flutes main voice editing screen

The main, tweakable organ parameters are:

  • Nine drawbars
  • Percussion (first note/each note, length)
  • Percussion pitch (4′, 2-2/3′, 2′)
  • Response (onset delay of drawbar and percussion sounds)
  • Vibrato (on/off, depth, speed)
  • Rotary speaker speed (slow/fast)
  • Volume level (1 to 8)
  • DSP effect (e.g., rotary speaker)

For B-3’ers, the 4′ percussion pitch is the 2nd harmonic setting and the 2-2/3′ percussion pitch is the 3rd harmonic setting. The 2′ pitch supports non-Hammond organs which require it.

Compared with a contemporary clonewheel, one immediately notes a few missing features:

  • Vibrato only, no chorus
  • No key click
  • No rotor noise
  • No leakage

Overall, the Genos B-3 is super clean and polite — not vintage. MODX (Montage) provides key click, rotor noise (grit) and rotor whistle waveforms. Why does Genos lag behind? Although MODX is AWM2, not modeling, these extra waveforms are better than nothing at all.

The Genos synthesis engine is also AWM2 sample-playback and AWM2 provides the Organ Flutes vibrato. Organ Flutes does not simulate the one-of-a-kind Hammond vibrato/chorus scanner. The Korg Module “Gospel Organ” voice incorporates C-3 chorus and the AMW2 vibrato just doesn’t cut it (head-to-head comparison). I had to substitute Genos’ V-2 setting and move on.

Simplified, graphical rotary speaker interface

If you want to change the rotary speaker type, you need to dive through the effect setting button at the top of the Organ Flutes screen. After selecting the insertion effect, Genos displays a skeuomorphic (graphical) rotary speaker cabinet with a few knobs. In the screenshot above, we get rotary speed, horn and rotor balance, and microphone left/right angle. Like many (most?) rotary speaker simulations, the rotary effect emulates the sound of a mic’d up, stereo recording of a Leslie, not a horn and rotor moving air in a room.

Additional rotary speaker (DSP) parameters are changed by tapping the “Detail” button in the lower right corner. deep-diving reveals a few more deficiencies:

  • Missing parameters due to a limitation on the number of DSP effect parameters (16 parameters maximum)
  • Only one insert effect (typically the rotary speaker)
  • Volume control is post-effect and does not affect overdrive

Here is a little more information about each issue.

First page of rotary speaker parameters

At heart, the Genos (PSR, Tyros) sound engine implements the Yamaha XG synthesis and effects architecture. The XG architecture allows up to sixteen (!6) parameters per DSP effect unit. Unfortunately, Yamaha’s DSP engineers are creating effect algorithms (AKA “effect types”) with more than sixteen parameters! The MODX ROTARY SPEAKER 2 algorithm has eighteen (18) parameters. The Genos REAL ROTARY effect type is the same algorithm as MODX. However, only 16 parameters are accessible or stored on Genos. The two missing REAL ROTARY parameters are:

  • Slow-Fast Time of Rotor
  • Fast-Slow Time of Rotor

You cannot change these rotor ramp times on Genos, yet, you can change them on MODX.

This issues affects the Genos UNI COMP compressor algorithm (MODX: UNIVERSAL COMPRESSOR DOWN). Dare I mention the inability to specify a side-chain part, too? People are trying to create EDM on arrangers.

The XG architecture allows only one insert effect per part. The Organ Flutes insertion effect is typically a rotary speaker simulator. The MODX effect architecture, on the other hand, allows two insert effects per part. Yamaha synths take advantage of the second insert effect to add overdrive or vintage EQ:

  • Rotary speaker 1 Multi FX (Distortion Solo)
  • Rotary speaker 2 VCM 501 EQ (Flat)
  • Amp Simulator 3 (Tube) VCM 501 (Flat)
  • Amp Simulator 1 (Stack 2) Rotary Speaker 1
  • VCM 501 EQ (Flat) Rotary Speaker 1

The rotary speaker drive alone is not enough to warm up the basic sound nor is it enough to get a sweet, realistic overdrive with guts. I experimented with the Genos REAL ROTARY effect and got some very squirelly results at high drive levels. The algorithm can be pushed in unexpected, undesirable ways while searching for true funk.

Unlike a real Hammond/Leslie combination, the Genos expression pedal controls post-effect part volume. This is like putting the volume control after the Leslie speaker. A Hammond B-3 pedal controls the level into the Leslie pre-amp. Thus, the pre-amp frequency characteristics and overdrive track the Hammond pedal. The Yamaha YC61 modeling gets this right. Putting the volume pedal before the pre-amp lets the player get clean or dirty in the same way a guitarist uses picking and/or the guitar volume knob to distort or clean up their tone.

If the Genos developers must work around the XG architecture, they should consider a new effect algorithm that combines overdrive with the rotary speaker simulation. The algorithm should allow foot pedal control over the Leslie pre-amp input level. Genos and other PSRs allow wah pedal control, so they obviously know how to achieve this capability within the current architecture.

Copyright © 2021 Paul J. Drongowski

Combo organ: Montage, MODX, Genos

Contemporary workstation instruments offer several options for combo organ emulation. Every workstation has at least a few internal combo organ waveforms. Korg Kronos, for example, has two Vox organ waves built in. Even the lowly Korg microKorg XL+ has two Vox waveforms (DWGS single cycle).

Yamaha MODX and Montage — my focus in this article — have a good variety of Vox and Farfisa waveforms. Yamaha Genos has a lesser endowment as we’ll see. Yamaha Reface YC shares sonic DNA (AWM2 and effects) with the Motif XF and will be the subject of a future post.

Motif, Motif ES and Motif XS

Models in the early Motif series primarily base combo organ patches on two waveforms:

  • Portable Electronic: Vox-y tone
  • Compact Electronic: Farf-y tone

You can hear these waveforms at work in the Tiny Combo Bars 1 performance and the Tiny Combo Bar 2 performance. The patches layer three are more elements playing Portable Electronic or Compact Electronic (respectively). Each element is filtered differently: low pass, band pass and high pass. The net effect is like several distinctive tab stops or drawbars pulled at once.

These waveforms are very old, going back to the original Motif (maybe S80) in the early 2000s. I’ll bet dollars to donuts that the Portable Electronic waveform is the basis for the 60’sOrgan voice (MSB: 0, LSB: 116, PC: 18) in PSR and Tyros keyboards. The 60’sOrgan voice was the sole combo organ mainstay in the arranger line for a loooong time.

Motif XF, Montage, MODX

Motif XF got a big shot of combo juice. Motif XF added several combo organ waveforms:

  • Fr All Tabs
  • Fr Bright Boost
  • Fr Flute
  • Fr String Lo
  • Fr String Hi
  • Fr Trumpet
  • Fr Piccolo
  • Fr Pedal
  • Fr KeyOff
  • Vx Drawbar1-3
  • Vx DrawbarIV
  • Vx KeyOff

The Farfisa (Fr) waveforms support emulation of specific Farfisa features: individual voice tabs (flute, string, trumpet and piccolo), the wicked Bright Boost knee lever, bass keys (pedal), and key off sound. The Fr All Tabs waveform covers one of the most common use cases — all of the tab stops turned on. Subtlety was not a hallmark of sixties combo organ music. 🙂

The Vox (Vx) Vx Drawbar1-3 waveform covers the three Continentel footage drawbars while the mixture drawbar is handled by the Vx DrawbarIV waveform. The Vox waveforms include a Vox key-off noise.

In terms of voice programming, one uses note shift to achieve different footage ranks. Passive filtering is emulated through filter type (low pass, band pass, high pass) and cutoff frequency. Of course, everything can be routed into insert effects for distortion, amp simulation, and other grunge.

Since Montage and MODX inherit all things Motif, these waveforms and the Motif performances are there for you. The Montage and MODX sliders allow control over individual voice elements. For example, choose the Raspy Tabs performance and assign slider control to element level. The Fr Raspy Tabs waveform-to-element assignment is:

El# Waveform     KeyLo KeyHi VelLo VelHi Coarse Level Cutoff XA Ctrl 
--- ------------ ----- ----- ----- ----- ------ ----- ------ -------
1 Fr String Lo C2 G8 1 127 0 97 255 Normal
2 Fr Trumpet C2 G8 1 127 0 82 255 Normal
3 Fr Flute C2 G8 1 127 24 120 236 Normal
4 Fr Pedal C-2 B1 1 127 0 127 160 Normal
5 Fr String Hi C2 G8 1 127 19 24 236 A.SW2 On
6 Fr KeyOff C2 G8 1 127 6 87 80 Key Off

Different tabs are brought in and out by moving the corresponding slider. Assignable switch 2 turns on additional brightness. The low keyboard octaves play the bass (pedal) tones. Overall, this is a fairly controllable representation of a wheezy Farfisa Compact.

Because the sliders are not discrete, you can probably make up Farfisa tones which aren’t entirely authentic. But, really, should one care? 😉

Vox performances have similar control-ability. Here is the waveform-to-element assignment in the Vx Full Bars performance:

El# Waveform      KeyLo KeyHi VelLo VelHi Coarse Level Cutoff XA Ctrl 
--- ------------- ----- ----- ----- ----- ------ ----- ------ -------
1 Vx Drawbar1-3 C-2 G8 1 127 0 75 255 Normal
2 Vx Drawbar1-3 C-2 G8 1 127 12 77 255 Normal
3 Vx Drawbar1-3 C-2 G8 1 127 24 91 255 Normal
4 Vx DrawbarIV C-2 G8 1 127 0 127 250 Normal
5 Vx KeyOff C-2 G8 1 127 4 68 85 Key Off

The first three sliders control the 16′, 8′ and 4′ Vox drawbar settings and the fourth drawbar controls the Mixture (IV) tone. Go ahead, just everything to eleven. 🙂

Montage and MODX FM

But, wait, there’s more! Montage and MODX have two FM combo voices: BOX FM Combo Organ and FM YC Combo Organ. Although these performances don’t sound authentic to my ears, they provide starting points for further programming. I haven’t heard the YC61 as yet, but I wonder if the YC61 combo emulations can be ported to Montage and MODX?

Genos

As I mentioned earlier, the arranger series has been historically short on combo organ sounds, relying on the old 60’sOrgan voice. Wheezy, raspy Farfisa tones are noticably absent. The 60’sOrgan voice sounds like the Portable Electronic waveform on which the Motif 1967 Keys performance is based.

Tyros 4 and Motif XF were introduced at approximately the same time. They certainly were together in the development lab during late 2009. Tyros 4 added four combo organ voices:

  1. 60sComboOrgan1: VoxContiComb1_Full_NoVib waveform
  2. 60sComboOrgan2: VoxContiComb1_Full_VibOn waveform
  3. 60sComboOrgan3: VoxCombi4NoVib waveform
  4. 60sComboOrgan4: VoxCombi4NoVib091117 waveform

Voices 1 and 2 capture one Vox Continental drawbar combination (Comb1) and voices 3 and 4 capture a second combination (Combi4).

Voices 1 and 3 are without vibrato. Voices 2 and 4, unfortunately, have an excessive amount of vibrato — almost painfully so. When I use voices 2 and 4 in a MIDI sequence, I dial down the vibrato depth using MIDI CC#77 messages. Vibrato frequency is about 5Hz. I also remove touch sensitivity by setting:

  • Velocity sensitivity depth to zero, and
  • Velocity sensitivity offset to 114.

An organ voice should not respond to touch (key velocity) — ever.

PSR, Tyros and Genos players shouldn’t forget the “hidden” Italian 60s organ voice (It60’sOrgan) in the GM2 sound set. On PSR and Tyros, you’ll find It60’sOrgan within the Legacy voices Organ subfolder. On Genos, you need to download GM2 and XG user voices to the USER voice folder. (See this thread in the PSR Tutorial Forum.) Of course, you can select
It60’sOrgan from a DAW (MSB: 121, LSB: 2, PC: 17) .

All-in-all, you can get a nice Vox tone out of Genos. Farfisa is still missing in action, tho’. Kind of an odd shortcoming of a keyboard with styles and a user base that want to play popular hits from days past.

In the next post, I’ll compare Reface YC combo organs against Montage/MODX (Motif XF). The result may surprise you.

Copyright © 2021 Paul J. Drongowski

What did you do in self-isolation?

Yes, this site still does music! 🙂

Several weeks ago, I decided to record the church tunes that I enjoy playing. It’s best to start with favorites, as most of you know how you come to detest a track after playing it over, and over, and over again during production. Energy quickly dissipates when micro-editing MIDI events or digital audio…

Before getting into production notes, here are links to the final tracks (all MP3). The goal was to crank out a new tune each week and send it to the folks in our music ministry. Some tunes are a little more polished than others. Please consider them “demo quality.”

Without going too far into the technical weeds, the primary sound source is Yamaha Genos™ and the primary vocalist is my spouse Fran. With the Mill Creek Chorale on hiatus — aren’t we all? — I was happy that she could contribute and have fun, too.

Production notes

So, how did all of this go down?

These demoes show off the Yamaha Genos as a sound source and production tool. I had two main subgoals:

  1. Learn how to record a demo with Genos in either audio or MIDI format.
  2. Learn how to mix down with Steinberg Cubase Artist and try out a few of the freebie plug-ins that I’ve collected.

By and large, Genos and Cubase were the main production tools although I back-slid into SONAR on a few occasions for MIDI editing. Old habits die hard. Workflow was not strictly linear from Genos to Cubase. In a few cases. MIDI and/or audio (stereo 16-bit 44,100 WAV) were slung back and forth between tools.

Yamaha Genos

Genos is the sound source with one big exception: drawbar organ. When you hear B-3, you’re hearing Yamaha MODX through an Electro-Harmonix Lester K. I wanted to hear Lester K in musical context. It sits in a song pretty well and has more guts than the Yamaha MODX Leslie simulator. By itself, though, Lester K has some high-end swirliness in the upper drawbars, but in a track, it seems to mesh. You be the judge.

Emphasis was on speed. Get the tracks down quickly and finish a song each week ASAP. The Beatles used to call this recording “on heat.” Even so, it’s amazing how modern technology will drag you into the dank chasm of production minutiae. Don’t you just love hearing the same three measures fifty times while tweaking and tweezing. Not.

All vocals were recorded directly to Genos using its microphone input. Full backing and raw vocal tracks were exported to Cubase via WAV. Everything was processed and mixed in Cubase. The final mix was exported from Cubase as WAV, and then trimmed and converted to MP3 using Sound Forge Audio Studio.

Our God Is Here This was the first demo in the series and the process doesn’t get any simpler than this. All was recorded into Genos Audio Multi Recording. Find a beat, turn it on, lay down the organ part. Unfortunately, I didn’t plan for the ending, which is quite ragged. The organ is Genos in this case (not MODX). Kinda plain, huh? The bass is an overdub.

Audio Multi Recording is a nicely done sound-on-sound recorder a la Les Paul, minus tape hiss. There are two stereo tracks: main and sub. You can record directly to either main or sub, and bounce (sub+main) to main. There are options for punch in and overdub. Audio Multi Recording provides WAV import and export, functionality which eventually got a true work-out.

Audio Multi Recording keeps digital audio in a persistent project. A project resides in the internal Genos 60GB user solid-state drive and is always ready. The project remembers audio and mix settings without requiring explicit save and load user operations. That makes for a clean workflow. Export is the way to get digital audio into a WAV file and it mixes the main and sub on the way to WAV. In order to export a solo vocal track from sub, one needs to dial down the main and then wait while Genos writes the WAV file in real time. I wish there was a simple, direct fast export to WAV supporting both main to WAV and sub to WAV.

In The Day Of The Lord I quickly realized that I do need to think ahead and assemble a basic skeleton on which I could build a tune. (Duh!) In this case, Toontrack EZDrummer provided the drum patterns which I pulled together in Cubase. Genos played the MIDI drum track while I recorded the flute as a melodic guide and layered in the bass and organ — all recorded as audio. We then did a few vocal takes to Genos. I transferred all of the Genos audio as WAV into Cubase for the final mix. Vocal processing typically was light: a little pitch correction, EQ, and maybe double tracking. A touch of reverb (Cubase Revelation) blends everything together here.

Stop By, Lord This tune makes use of the Genos rhythm accompaniment consisting of main patterns and one-bar fills. I recorded a basic guide track in MIDI using the “BigBandBallad” style as the drummer. This meant switching the main and fill patterns with my left hand while playing the melody with my right hand. I layered in the piano, bass and horns, discarding the guide melody along the way. I added the B-3 organ (MODX through Lester K) in an audio pass. Everything was recorded and produced on Genos since we didn’t record vocals.

Psalm 95 If Today “If Today” makes full use of the Genos arranger features. I played the basic accompaniment track using the “Sunny Reggae” style. Whoever built that style, it must have been a labor of love and it fits this song quite well. I vocoded my voice. Both the accompaniment and vocal tracks where exported to Cubase for final assembly and mix down. I had a lot of fun adding dub effects and tons of reverb, Long live King Tubby!

Rise Up With Him “Rise Up” was recorded to MIDI, again using the Genos rhythm accompaniment as the drummer. The electric piano went down first followed by the bass. The B-3 organ is MODX through Lester K. Backing and vocal audio were exported to Cubase for final mix down. Overall, a pretty simple demo to pull together.

O Sacred Head I recorded the MIDI for this tune a long time ago — in the early 2000s on a Roland XP-60. The guitar picking was carefully edited and assembled (years ago!) from Twiddly Bits. I imported the XP-60 MIDI into Cakewalk, choosing Genos voices and effects. The Genos result versus the original XP-60 is amazing. Fran encouraged me to leave it as an instrumental.

This Is The Day This psalm is long out-of-print. A few years agao, I transfered a scruffy copy of the piano score into Sibelius. So, to kickstart this tune, I exported MIDI from Sibelius, restructured the sections, and humanized the piano as much as possible. I tried to keep the accompaniment simple adding just bass and horns. Once again, the backing and vocal tracks were mixed in Cubase. This demo is a good example of Arturia’s Plate-140 reverb — a freebie that Arturia gave away during the Christmas holiday. I love it.

Lead Me, Lord Another simple turn-on-the-beat-box, sound-on-sound production. Everything was recorded to Genos with the backing and vocal tracks exported to Cubase. (Another example of Plate-140, BTW.) The vocal harmony was generated by a TC Helicon Play Electric added in real time. Recording and production was dirt simple although it took a while to get the TC Helicon configured.

Alleluia! Love Is Alive This was the penultimate demo in the series. The basic track is a stripped down Genos “6-8PopBallad” style. Yamaha tends to over-orchestrate styles, so I kept drum, bass and guitars, tossing the rest. Instead of playing the basic track, I created the accompaniment using chord step-record. This MIDI Multi Recording feature lets a musician enter chords and sections from a lead sheet, quickly creating the song skeleton. You can even try different styles if you haven’t chosen one already. Once the skeleton is set, you expand the chord track into MIDI events, thereby obtaining the full backing track in a Standard MIDI File (SMF).

I added the Celtic violin by playing it into a free MIDI track. Using Sonar, I tweaked the tempo in the full MIDI song in order to add energy as the song progressively builds to the end. Finally, with the MIDI finished, I froze the backing tracking to WAV audio. The backing and vocal tracks were mixed down in Cubase with a little automation here and there to add vocal depth and double tracking.

Conclusions?

The preceding discussion is already a lot to absorb and to process. I’ll take a step back in a future post and try to summarize. All the best to ya.

Copyright © 2020 Paul J. Drongowski

Musing about Montage VA

There’s been an extended discussion in the YamahaSynth.com Montage Forum about the ability to add Virtual Analog (VA) synthesis to the current Montage and MODX platforms. It’s been a good discussion and it encouraged me to jot down a few musings about the hardware support for AWM2 and FM-X.

In case you don’t visit YamahaSynth.com, I reposted my musings here and added a diagram or two.

Before saying anything, I have to emphasize “Speculatively speaking.” With as much invested in AWM2/FM-X and their implementation in silicon, Yamaha have not published about the internal design. This whole discussion — including my own comments — would be on much sounder footing (no pun intended) if the micro-architecture were published. Yamaha are tight-lipped so “Hah!” to us all. 😀

BTW, we’re lucky that we can speculate at all since Korg, Nord, etc. have largely buttoned up their service manuals.

I’m skeptical

I’m skeptical about adding VA through an update given the current platform because of limitations in the current synthesis pipeline.

Yamaha regard their expertise in large scale integration as a strategically important asset. (Please see their annual financial reports.) The SWP70 is a major investment in the future. It’s a generational step and a design with a long expected life time. A long life is needed in order to recoup Yamaha’s investment. Thus, we haven’t seen all of its potential capabilities as yet.

At some point, the current hardware platforms (Montage and MODX) will limit the features which can be delivered solely through software. That will necessitate a new hardware model in each product line. Speculatively speaking, I’m not sure if the SWP70 is capable of CS-like VA synthesis. The Reface CS (and DX) employ a Yamaha SSP2 (SH-2 CPU core) for synthesis. The mere presence of an SSP2 in the Montage is not significant for VA because it clearly supports UR-like digital audio in the existing design.

Of course, business decisions will take precedence eventually. We all love the free updates and improvements in our instruments. (I certainly do!) Like cellphones, tablets and other high-end electronics which enjoy periodic updates, we will need to buy a new upgraded platform in order to fuel the future. Nobody rides for free forever.

My mental model

I suspect that we nerds (and I mean that as a compliment!) have different architectural models in mind as to the SWP70 internals. One model is the “standard DSP” model — a pipelined single instruction, single data (SISD) CPU. Naturally, there may be enhancements for vector processing instructions and so forth.

An example of such a generic model is the Yamaha SSP2, which consists of an SH-2 DSP core and several effect DSP processors. The SSP2 is the heart of Reface CS with an internal clock of 135.4752MHz (a multiple of 44,100Hz, BTW). Another example would be the DSP56362 in early Nord/Korg modeling keyboards. The Reface CS manages 8 voices of polyphony (using the word “voice” loosely) with the effects handled by the SSP2 effect DSP processors. (The effect DSP processors are mini, small core, reprogrammable processors.)

The architectural model which I think is used in the SWP70 is a SIMD architecture more akin to a GPU. The Montage/MODX DSP RAM and wave work RAM memory clock is 95.9616.MHz, also a multiple of 44,100Hz. The SWP70 pumps out a finished sample every 2,176 memory clock ticks. The internal clock is probably a small multiple (maybe two) of the memory clock. Everything needs to run in a modest power envelope without a heat sink, etc., so it’s not possible to run at GHz rates.

After writing this, I realized that the AWM2/FM-X synthesis core may not have an instruction stream at all. It might be a block of 1 to N dedicated pipelines where each pipeline is, roughly speaking, an AWM voice element.

I image a block of tone generation (TG) cores dedicated to AWM2/FM-X. Part of that “dedication” is a pipeline specifically tailored and tuned to AWM2/FM-X. (I believe this design IP (the basic core design) is re-used in other AWM2 products.) Yamaha are in the AWM2/FM-X business so it makes sense to design hardware specific to these tasks. It’s no simple feat to produce 128 channels of tone generation with low latency and no burps and hiccups.

I don’t know how much flexibility is built into the so-called “oscillator” part of a TG core pipeline. Could Yamaha write a new SIMD program for VA using the existing TG core design? I don’t know and hence, my doubt.

That said, since Yamaha haven’t published a darned thing and my job easier (Hah!), I could be totally wrong. Yamaha are smart engineers, especially at the hardware level.

The choices made for Reface may or may not be revealing. Reface YC/CP use the SWX08 for AWM2/SCM synthesis. The SWX08 — in my imagination — use a similar AWM2 TG core assist. Reface DX/CS use SSP2 and its SH-2 core. Was something missing in the SWX08 TG core which was available later in the advanced SWP70 cores? Did SWP70 become VA capable as well?

Example: Yamaha YMW820

The closest I’ve ever gotten to understanding Yamaha’s approach to AWM2 is by studying the datasheet and MIDI spec for the YMW820 (NSX-1). Admittedly, the YMW820 is a low-end device implementing a large subset of the XG voice architecture with only chorus, reverb and a single variation effect.

YMW820 (NSX-1) block diagram

The YMW820 has a control CPU (dual issue, 32-bit RISC), mixer hardware, DSP for effects, and a “wavetable synthesis core” (Yamaha’s exact terminology). Both the synthesis core and DSP are controlled by the CPU.

The wavetable synthesis core supports 64 channels (polyphony). The YMW820 has a 2MByte wavetable ROM which presumably contains the General MIDI waveforms. It also has a 3 MByte wave RAM which can be loaded with eVocaloid waveforms or Real Acoustic Sound (Articulation Element Modeling).

The 64 channel synthesis core is drawn as a distinct hardware subsystem from the effects DSP. Each channel is what we consider an element: pitch generator, oscillator, digitally controlled filter (DCF), envelope generator (EG), LFO. I suspect that other AWM2-based products have similar wavetable synthesis cores, including the SWP70. [Click image below to enlarge.]

YMW820 (NSX-1) synthesis core and effect DSPs

Of course, the SWP70 synthesis core is the ultimate in the entire AWM2 family. It also has many effect DSPs for system and insertion effects.

Bottom line, Yamaha exploit massive parallelism for AWM2 synthesis where each channel is a wavetable synthesis element. A true DSP processor like the SSP2 is better suited for VA synthesis which is why the SSP2 is deployed in the Reface CS, not an AWM2-oriented SWX processor. (The SWX has an embedded wavetable synthesis core, too.) I believe that Yamaha will need to add another SSP2 (or some such) to the Montage in order to implement VA. There’s a reason why it’s called a “Standard Wave Processor” — it is hardware specifically designed for AMW2, FM-X, AEM, and SCM synthesis. It isn’t a general purpose programmable DSP. Maybe VA can be warped to the existing pipeline(s), maybe not.

BTW, the new VCM MINI FILTER and MINI BOOSTER are DSP effects. The effect DSPs are programmable — the AWM2 channel filters likely are not.

Big DSP vs. little effect DSPs

I tend to think of the internals as a tone generation front end followed by a flock of small DSP units in the mixer/effects back-end. This seems to be the canonical Yamaha pipeline. In Montage/MODX, some of the small DSPs are routed as insert effects and some as system/master effects. (The effect routing in Genos, BTW, is different and probably different in the high-end digital pianos.) I suspect that the data flow is predominantly (solely?) front to back.

I don’t really know if the small effect DSPs are general purpose or not.They are probably small simple cores because an SWP has at least 15 and real estate is limited. (Lower capacity parts like the SWXs and SWLs have far fewer small DSP cores.) A small core may not have much throughput and the front-to-back dataflow might prevent feeding data from the DSP cores back to the filters, etc. in the front-end.

There is also the issue of getting note and controller data to the effect DSPs in the back end. Note and controller data are delivered on the E-bus directly from the key, knob, slider, etc. scanning processor(s) to the tone generation core. Does all E-bus data get back to the small DSP cores? Certain some data gets through as knobs, sliders, etc. can tweak effect parameters in real-time.

Overall, even as a consumer, I would be happier with a dedicated SSP2 for VA. The VA SSP2 would inject its digital output stream into the existing mixer/DSP infrastructure. [The SSP2 vocal harmony processing does something like this in Tyros5.] The VA SSP2 gets its own DSP RAM and NOR flash for program, and the processing is totally out of the way of FM-X and AWM2. It would be possible to implement different VA algorithms without making compromises. Yamaha could periodically offer new engines as updates/upgrades.

If you’re an ARM aficionado, you might be thinking “big.LITTLE”. It’s a similar concept. Engineers need to make best use of limited real estate. Yamaha need lots of little DSPs for insertion effects. The SSP2 itself is organized as a big SH-2 DSP core and several little effect DSPs (plus a digital mixer). The mix of channel strip and guitar effects is limited.

Down memory lane

The discussion took me down memory lane to the venerable AN-200 and PLG150-AN. Both products use Yamaha’s AN (Analog Physical Modeling) daughter card. I love the old AN-200 and keep one handy. It is a pretty decent approximation of a five voice Prophet 5.

The daughter card contains two Yamaha LSI components:

  • YSS-236-F: An enormous 160 pin QFP for analog synthesis
  • YSS-233-F: A merely huge 128 pin QFP for mixing and effects

The 236 is also known as the “VOP3” and the 233 is known as the “MDSP”. The MDSP is deployed in the PLG150-DX daughter card, again in the mixing and effects role. The An1x, by the way, has two of each, implementing ten voice polyphony.

Some sites ascribe synthesis to the Hitachi H8/3002 on the daughter card. This is wrong. The H8/3002 is the microcontroller that issues commands and maintains digital communication with the mothership. The VOP3 does synthesis.

The VOP3 moonlights as the vocal harmony processor in early arranger keyboards like the PSR-9000. The VOP3 is the predecessor to the SSP and SSP2. The SSP and SSP2 subsume the mixing and effect DSP roles of the MDSP. Such is the march of large scale integration (LSI) fabrication technology.

Given this history, I’m not surprised that Yamaha chose the SSP2 for Reface CS.

I like surprises

Watch, Yamaha will come up with something completely different. 😀 Maybe an SWP71. There were different spins of the SWP50 family, so why not? 🙂 From the marketing point of view, demand for VA is sufficiently high that they may require everyone to buy a new platform anyway. Perceived value means “mo’ money.”

Copyright © 2019 Paul J. Drongowski

Yamaha MODX: Inside stuff

Time for a quick look at the MODX internal hardware. I’m going to be brief, so please read my Yamaha Genos articles (main CPU and tone generation) and my Montage internals article for more details and background information.

The MODX main CPU subsystem should look familiar. It is essentially the same as the Montage main CPU subsystem. Again, the Texas Instruments AM3352 Sitara ARM microprocessor is the star, providing many of the important internal device interfaces. The eMMC bulk storage device is still 4GBytes although the MODX eMMC data clock is slightly slower than Montage (48MHz instead of 52MHz). Deja vu all over again.

MODX Main CPU (Click to enlarge)

The MODX is a reduced-spec Montage. Although the MODX has the same waveforms and Performances as Montage, its polyphony is less:

  • AWM2: 128 (maximum; stereo/mono waveforms)
  • FM-X: 64 (maximum)

The keybed is lower quality (semi-weighted vs. FSX) and the MODX front panel is greatly simplified.

Both products employ an MB9AF141NA ARM microcontroller for user interface scanning assisted by an 89FM42AUG logic device (E-GKS) for keybed scanning. User input (e.g., controller messages) are sent to the Master SWP70 tone generator over the EBUS. The EBUS is a low-latency path for controller input and commands, making for a responsive instrument with excellent hand-to-sound connection.

MODX Tone Generation (Click to enlarge)

When we look at the MODX tone generation subsystem, we immediately see why the FM-X spec is lower. The MODX has only one SWP70 tone generator integrated circuit (IC). The Master SWP70 performs both AWM2 and FM-X synthesis. The MODX printed circuit board (PCB) has space and connections for a second SWP70 (in Slave mode), but the real estate is unpopulated (“No Mount”). Yamaha have planned ahead for a future model. They did the same thing with the MOX, BTW, leaving space and connections that were filled in the MOXF.

The extra computational capacity within a single SWP70 is surprising! The Master SWP70 provides 128 channels of AWM2 polyphony and 64 channels of FM-X polyphony. In order to pull off this trick, Yamaha utilize a second dedicated DSP RAM channel and SDRAM. Montage, on the other hand, utilizes only one DSP RAM channel on each SWP70.

Thus, the SWP70 can expand in two different dimensions:

  • DSP RAM (two dedicated channels max) with a corresponding boost in DSP computation, and
  • Wave RAM (two dedicated channels max) with an as-yet unexploited boost in AWM2 synthesis.

MODX illustrates the first case while Montage has an unpopulated position and connections for a second WAVE working memory channel. Your guess is as good as mine as to how Yamaha will expand and exploit these channels in future products.

The MODX serial digital audio bus is a subset of Montage. An SSP2 processor supports audio-over-USB through the USB TO HOST interface, just like Montage. However, the overall spec is substantially reduced. A single DAC drives the MAIN and PHONE outputs. A single ADC encodes incoming stereo audio from the A/D input. The SSP2 does not have a direct channel to an SSP2; the needed logic device is missing from MODX.

In case you’re wondering about serial audio bus clocking, the bus clock is 11.2896MHz. The clock speed is 256 * Fs, where Fs is 44.1kHz. In MODX and Montage engineering-land, this signal is known as M_SYSCLK. Genos engineers refer to this signal as mcasp-256fs. The different terminology doesn’t help comparison across product lines! Bottom line, the master clock is fast enough to support 32-bit 44.1kHz stereo audio. Currently, only the Genos has a 32-bit DAC for its MAIN out, BTW.

Our look inside MODX shows how Yamaha can manufacture the MODX at a lower price point. More significantly, perhaps, is the cost leverage gained by reusing the Montage software and sound content. I think sometimes arguments on the Web play up component cost while neglecting manufacturing, software and sound development costs. I suspect that software and sound development (waveforms, voices, arpeggios, styles, etc.) are a very large fraction of unit cost.

We also caught a glimpse of what’s in store for the future. SWP70 is in early childhood and Yamaha have left room to grow in both the MODX and Montage. In addition to unpopulated PCB sites, Yamaha can build out by using higher capacity NAND flash devices for waveform memory. I’ve said it before — the real limiting factor is Yamaha’s capacity to produce high-quality content — a labor intensive job. Ultimately, the payroll is more important than the cost of commodity NAND flash!

Montage digital audio clocking

I’m still thinking this through…

The Montage USB audio interface supports 44.1kHz, 48kHz and 96kHz sampling frequencies. The number of supported audio channels depends upon the chosen sampling frequency as defined in the specs:

“[Sampling Frequency = 44.1kHz] Input: 6 channels (3 stereo channels), Output: 32 channels (16 stereo channels)

[Sampling Frequency = 44.1kHz – 96kHz] Input: 6 channels (3 stereo channels), Output: 8 channels (4 stereo channels) “

The MODX USB audio interface is strictly 44.1kHz supporting:

“Input: 4 channels (2 stereo channels), Output: 10 channels (5 stereo channels)”

The digital audio bus master clock is a multiple of 44.1kHz, so how does Montage handle 48kHz and 96kHz?

The Montage SSP2 processor handles 44.1kHz, 48kHz, and 96kHz internally. The tone generators, however, are 44.1kHz only. A-ha! That explains the function of Montage’s SRC16 gate array. The gate array is clocked at 49.152MHz, which is a multiple of 48kHz. It converts the sample rates and samples between 48/96kHz and 44.1kHz in DAC-A format (2 channels per line).

The schematic notations on SRC16 match the Montage 48/96kHz spec:

Output: SWP->SRC->SSP2 8 channels (stereo 4 channels)
Input: :SSP2->SRC->SWP 6 channels (stereo 3 channels)

Someday I will explore the Montage/MODX subsystems in more depth.

Copyright © 2019 Paul J. Drongowski
Diagrams are from the MODX Service Manual (copyright Yamaha) .