Critique: Genos™ drawbar organ

Posted on October 25, 2021 by pj

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.

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.

SampleTank IOS and Miroslav vs. Korg Module Pro

Posted on October 21, 2021 by pj

Just like finding a 20 dollar bill in a drawer full of old socks, it’s a pleasant surprise to discover that you already own a useful iPad music app and simply forgot about it. Thus, I installed IK Multimedia SampleTank IOS on my iPad and gave it a try. (Again) Even better, I restored in-app purchases, finding additional B-3 organs and, ta-da, Miroslav Symphonic Mobile Edition. (Henceforth, “Miroslav”.)

Miroslav goes back a long way to 1994. The mobile edition is a cut-down version of the current, big and improved Miroslav Philharmonic 2 library. The full library is 2.27GB while the Mobile Edition tips in at a modest 532MB.

Miroslav Vitouš, by the way, is one heck of a jazzer. I was well-aware of his work as a leader and as a sideman (Herbie Mann, Chick Corea, Roy Ayers, Larry Coryell, and others) before hearing the original Philharmonic library.

Sonically, Miroslav has always had its own unique character. You either love it or dislike it. I’m on the love side although some of the string sections sound a tad dated. I like the woodwinds and horns best, rating them a notch above the Korg Module Pro voices. As to variety and solo instruments, Miroslav Mobile trounces Module Pro in the orchestra department.

As to B-3 organs, Module Pro wins the contest. Frankly, I am not a fan of SampleTank IOS drawbar organs, which are very rock-oriented. Further, SampleTank IOS does not have a rotary speaker simulation built-in. I can only assume that IK want you to purchase Hammond B-3X for iPad ($130 USD) or AmpliTube Leslie. I found, however, that I can easily switch between Module Pro and SampleTank IOS while keeping the Korg Microkey Air connected over Bluetooth. Problem solved.

As to church organ, I blended SampleTank’s Church Organ Air with Miroslav’s Cathedral Organ. The solution is good enough for basic hymn playing. I still plan to purchase Module’s organ (and clav) expansion pack when it goes on sale. The organ expansion pack includes a few traditional pipe organ voices.

SampleTank IOS plus Miroslav Mobile complements Korg Module Pro rather well. I forgot about dear old Miroslav after moving to our new house and to a new iPad. I’m glad that I remembered! If you need to choose one app, there are differences to be considered in the synth engines. Please read on.

Korg Module Pro

As I mentioned in my review, Module Pro with the performance expansion pack allows two-voice layers and splits. Splits and layers are created and stored within set lists.

Module’s Set List management screen lets you choose and load a combination (combi). Tapping the keyboard symbol on the right hand side of the selected entry takes you to the screen where you set the mode: Single voice, Layer or Split. There, you can balance levels, shift octaves and set the split point.

If a voice needs tweaking, you can switch to the standard Module instrument screen for voice edits. When finished, you need to switch back to set list mode and save the set list. The set list combi retains any changes. (You need to tap the file icon in the upper left corner to show the appropriate pop-up menu.)

Korg Module Pro edit screen for sample-playback voices

SampleTank IOS

Instead of set lists, SampleTank has its Live mode where you can create multi-voice layers and splits. SampleTank is better-featured that way, allowing up to eight voices to participate in a combi.

In the example above, instruments are split left (two string layers) and right (two flute layers). You can see the split and layer relationships in the pane at the bottom of the screen. Since it’s all touch-based, one slides split points left and right. It’s quite natural. Please note that this example patch is already well-beyond Module Pro’s simple two-level layers and splits. SampleTank IOS also allows overlaps around the split point, eliminating a jarring sonic change when a musical line crosses the split point.

Unlike Module, SampleTank IOS has a strip of control knobs for voice tweaking. Both apps let you change attack, release, cut-off, resonance, effect type and effect levels. This level of basic editing is usually sufficient.

SampleTank IOS level and pan control in Live mode

All four voices in the example are on MIDI channel 1. Thus, all four individual voices sound (modulo splits and layers) when a note is struck on the Korg Microkey Air. In order to set volume and pan levels, one taps the slider icon in the upper middle part of the screen. When mix is enabled, each part box shows a volume and pan knob.

Overall, I give the win to the SampleTank engine. Eight layers/splits is more than enough and there isn’t any need to change modes or screens in order to make voice edits.

Module Pro set lists have mo’ power, however. You can attach audio songs, PDFs and other performance aids to a set list entry. I find the iPad screen too small for most of my charts, so I’m not taking advantage of those particular set list features. Access to performance aids might tip things toward Module Pro, if that’s your thing.

Korg Module Pro for church

Posted on October 12, 2021 by pj

Over the last several weeks, I’ve been practicing and playing through church tunes. Our liturgical group covers genres from pop, light rock, classical and traditional hymns to gospel. I’m trying to keep up my chops while our group awaits its post-pandemic return.

This has been a good opportunity to wring out any issues with Korg Module Pro (on Apple iPad) and a Korg Microkey Air 49 controller. Both Korg products have been solid and I feel comfortable with the idea of using this combo live in church.

I’ve also been able to evaluate the suitability of Korg Module for our church repertoire. Module’s set-list features are very easy to work letting me build quick-access layers and splits. Set-list features are well thought out and I strongly recommend purchasing the Module Performance Expansion.

Thankfully, set-list combis store patch and effect edit, allowing me to dial in a consistent level across combis and to tweak attack, release and reverb. Just don’t forgot to save the set-list after making edits!

Right off the top, I’m quite happy with Module’s stock Hammond organ sounds. My three favorite patches are Gospel Organ, Simple Organ and Clean Organ. Church music doesn’t require over-the-top distortion. The Korg rotary speaker simulation is very good and the speed transitions (ramps) are realistic — a vital component for gospel music.

The only thing missing organ-wise is a traditional church organ. I have not purchased the Korg Organ and Clav Collection which offers a classic organ. I intend to buy the organ expansion during the next Korg app sale. In the meantime, I’m substituting Simple or Clean organ.

As to other instruments, I need orchestral woodwinds, French horn, and strings. Compared with Miroslav Philharmonik Mobile Edition, Module Pro is a general purpose, all-rounder, not a specialist like Miroslav. The sounds are good enough for live play, but would not please a purist. Nor would they be adequate for mocking up symphonic music.

Korg offer the KA Pro Orchestral Dreams expansion. “KA Pro”, by the way, means Kurt Adler Productions, who sell a full range of orchestral samples. If Korg Module isn’t to your taste, the KA Pro samples are available in the CrudeByte iSymphonic Orchestra (iPad) app. Orchestral Dreams is comprised mainly of full orchestra emulations. The emulations implement multiple velocity levels including percussion. Full orchestra emulations are not suitable for our repertoire (especially the percussion!) and I don’t plan to buy this expansion.

The Korg sounds make for good layers. The Woodwind Ensemble patch is serviceable by itself, but is fuller and warmer when layered with the Horn Ensemble voice. Same for the Solo Flute. By itself, the Solo Flute resembles a Mellotron flute, especially when playing chords or clusters. Horn Ensemble knocks down the tron-y flavor.

Here’s a quick list of my favorite patches: Wind Ensemble, Horn Ensemble, Synth Horn, Romantique Strings, Strings Pad, Solo Flute.

What’s missing? Module has solo violin and cello, but it’s missing most other solo orchestral instruments (including essential double reeds). The violin and cello voices have hard attacks and a lot of bow — difficult to tame. Thus, overall playing is limited to mainly ensemble or pad-like voices. Quite the shame. Korg need to add an orchestral expansion with solo instruments and/or small sections a la Miroslav.

Yes, I auditioned the Triton expansion pack. Having owned a Triton Taktile 49, I’m not satisfied with the Triton orchestral voices, solo voices, in particular. That’s why the Triton Taktile is gone, gone, gone.

Oddly, I have not found a simple synth pad among the plethora of synth patches. I want something very light and plain for layering — a non-fat synth pad without sweeps, sparkles and other tricks.

Functionally, I wish layers could cross-fade (“tilt”) across the keyboard. This would let us overlap (cross-fade) the upper and lower instruments forming a soft split. Hard split points are rather jarring when a right- or left-hand line needs just a note or two past the split point. Examples include Oboe/Bassoon or Oboe/Cello splits where a short blend across the split point is highly desired for continuity.

Overall, Korg Module Pro is a solid, reliable citizen within its limitations. Module is intended to appeal to and serve a wide range of users. If you need good electric piano or high-quality acoustic piano, it’s got ’em, too. I stand by my earlier positive recommendation.

Check out these related blog posts:

Review: Future Kit FK651 stereo simulator

Posted on October 7, 2021 by pj

The Yamaha PSS-A50 is strictly MONO OUT and needs a little spice. After trying the Haas effect via a Synthrotek Dev Delay, I ordered a Future Kit FK651 Stereo Simulator. Future Kit — also known as “Thai Kits” — offers a range of audio kits including the FK651. I ordered through Amazon with Future Kit in Thailand handling fulfillment. Thanks to the pandemic and global shipping delays, I finally received the FK651 after a few weeks of waiting. Can’t blame Future Kits for the delay. They shipped right away putting the FK651 on the proverbial “slow boat from Thailand.” Thanks, pandemic!

Future Kit FK651 Stereo Simulator (click to enlarge)

The FK651 takes a MONO signal, splits it, and sends each side into a short filter chain. The left and right filter chains have different peak frequencies:

    Right channel 
    ------------- 
        32Hz  (Note C1) 
        500Hz (Note C5) 
        2kHz  (Note C7) 
    Left channel 
    ------------- 
        64Hz  (Note C2) 
        1kHz  (Note C6) 
        4kHz  (Note C8)

The filter chains alter each side of the stereo pair just enough to create the impression of different source signals coming from the right and left channels.

Kit of parts

The FK651 kit is fairly small making it suitable as a PSS-A50 mod. The small board should fit easily within the PSS-A50 even with the A50’s rather large speaker. I tested the FK651 with a 9V battery and it worked well even though 9V is below the suggested 12V supply voltage. I’m hoping to tap power from the A50’s 6V battery supply. Fingers crossed.

You’re not seeing double in the picture above. I ordered two FK651 kits. By the time I paid for one kit and shipping, it wasn’t much more to order two just in case I blew up a kit. It’s happened to me before, e.g., horribly destroying a Blokas MIDIboy during assembly.

Part and board quality are good.

Assembly

Assembly is straightforward. Given the number of parts, I assembled the kit in four phases:

Resistors
IC sockets and quad op amps
Capacitors
Wiring

Due to the placement of the power and audio pads, I couldn’t use terminal blocks. I decided not to use the enclosed terminal pins and soldered external connections directly to the printed circuit board (PCB).

Future Kit FK651 Stereo Simulator (assembled)

There were two minor concerns. Although the printed directions are OK, the instructions do not include a resistor color code chart. If you decide to build an FK651 of your own, here’s my look-up chart.

Ohms       Resistor color code 
----       ------------------------ 
220        Red    - Red    - Brown 
470        Yellow - Violet - Brown 
1K         Brown  - Black  - Red 
2K         Red    - Black  - Red 
4.7K       Yellow - Violet - Red 
15K        Brown  - Green  - Orange 
47K        Yellow - Violet - Orange 
56K        Green  - Blue   - Orange 
100K       Brown  - Black  - Yellow 
470K       Yellow - Violet - Yellow

The second concern is a single inconsistency between the parts provided, the schematic, and a silk-screened legend on the PCB. [Does anybody use silk-screening anymore?] I found a 4.7K resistor when the PCB called for a 47K resistor. The part placement picture on the paper instructions has it right — “4K7”, the alternative way of writing “4.7K”. The PCB legend says “47K” and is wrong. Otherwise, it’s all pick, place and solder assembly.

The picture above shows the completed board ready for testing. The audio wires come out to 3.5mm jacks with ring, sleeve, tip (RST) terminal blocks. This should make it easy to reconfigure the FK651 during bench experiments.

The power cabling may look unnecessarily complicated, but I decided to experiment in preparation for possible integration with the PSS-A50. The JST connectors should make for plug and play with the A50. The power wires solder into a tiny “distribution board” that I nibbled out of an old proto-board. The result is a tad ugly.

Use

Power up and the FK651 works the first time. 🙂

As to testing, perceived effect depends upon source material. I had reasonable success with a drum loop (WAV demo). The first half of the demo is the direct A50 audio and the second half is FK651 simulated stereo.

I applied the FK651 to a full mix (WAV demo). Again, the first half of the demo (about 10 seconds) is the direct A50 audio and the second half is simulated stereo. With the full mix, there is a clear difference between direct and effected. Whether it’s a stereo effect or not is subjective.

Clearly, the FK651 messes with the distribution of energy across the frequency spectrum. The effected full mix demo audio has less bass. As it is, the FK651 has a profound effect on a mix, maybe an unwanted effect that undoes your hard work balancing and mixing. The FK651 may be best applied to individual instruments, not a full mix.

Full mix direct and effected spectrum (click to enlarge)

I experimented with ways to visualize the FK651 at work. Here is a false-color spectral plot for the full mix demo. The left and right channel plots are identical during the first half when the right and left channels each carry the same signal. During the second half of the demo, the right and left plots show differences due to the different filter chains applied to the left and right signals, respectively.

As to signal gain, boy, there is an abundance of gain! The A50 line OUT is the headphone OUT, which itself is a fairly hot signal. The FK651 adds even more gain. I had to attenuate source signals heavily in order to sample cleanly without distortion. I also had to carefully balance the level of the first and second halves of the demo to avoid the “louder is better” bias of human hearing.

There are still a few more experiments to try. First, it might be helpful to mix a little of the original source signal into both the right and left channels as a way to mitigate loss in specific frequency bands. This may also be a way to control the depth of the simulated stereo effect (dry plus wet). Another trick to try is putting delay on one of the outgoing channels to enhance the Haas effect.

All in all, the Future Kit FK651 Stereo Simulator is an easy build and a fun toy (tool). It’s not a be all or end all solution. The Volca Mix stereo spread effect beats the FK651 hands-down. The FK651, however, is small and inexpensive enough to deploy in a circuit mod as long as you can tame its gain.

Sand, software and sound

Electronics and computing for the fun of it

Monthly Archives: October 2021