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Sequential Fourm 4-Voice Analog Synthesizer with Polyphonic Aftertouch
MSRP: $99900
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About Inventory Status
About Inventory Status
Questions? Call or text us at 301-946-8808.
♫ In stock: It is in stock and available to ship or pickup. Apparel must be shipped from another location and is not available for in-store pickup. We can usually ship or have these items available for pickup by the next business day if they don't require inspection, special handling, or setup. Our pickup location is 11151 Veirs Mill Rd. Silver Spring, MD 20902.
📆 Preorder: It is on the way to our warehouse. We can't predict when preorder items will arrive due to current supply chain issues. If you place an order for one of these items someone will contact you to estimate the delivery date.
❓ Out of stock: We don't currently have it available but you're not out of luck yet. We still may be able to get it. If you order one of these items we will contact you with an estimated fulfillment date. You have the option to cancel the order if you change your mind.
❔ Special order: The item is so special that it needs to be custom ordered for you. Some of these items are works of art and have to be made individually. Orders for special order items must be prepaid and we cannot accept cancellations or refunds.
█ Sold out: We don't think we can get this item because it was either discontinued by the manufacturer or was limited in quantity. If you want or need this item call or text us. Sometimes we can help you track down the item through other sources or help you find something similar.
About Item Conditions
About Item Conditions
Questions? Call or text us at 301-946-8808.
New: The item is brand new as received from the manufacturer with a full manufacturer warranty. Instruments such as guitars, snare drums, drum kits, brass and woodwind instruments may be opened for photography and quality control inspection and may not be in a factory sealed box.
Mint or Open Box: The item may have been opened and tested but has been repackaged. The original packaging may have superficial issues but the item itself and any originally included accessories are in perfect, like new condition.
Display Model: These items are so cool that we put them on display in our legendary shop. The condition is brand new as received from the manufacturer with manufacturer warranty. Rest assured, these items undergo a very careful inspection before shipping.
Demo: These items have been on our sales floor for demo purposes and will likely show signs of use. The original packaging may no longer be included, but you can be assured that you are receiving an awesome item and an awesome price.
Used: The item is used. These item may have varying degrees of wear. Please read the description for information about the condition of the item. Used items do not carry a warranty.
B or C Stock: Factory refurbished. These items were purchased from the manufacturer in a refurbished condition. They will show some cosmetic issues, but nothing that would impact performance. Being that these are sealed from the manufacturer, we generally do not open these to photograph the cosmetic issues. They are guaranteed to work and may have a limited warranty or you may purchase an extended warranty in some cases. Please see the listing description for item specific information.
Description
Description
Perform Expressively - The Sequential Fourm 4-Voice Analog Synthesizer with Polyphonic Aftertouch
Fourm is a compact analog synthesizer that invites you to play, shape, and perform with unprecedented expression. With its legendary Sequential tone, hands-on modulation, and uniquely responsive keybed, Fourm is a creative partner helping to bring your musical ideas to life.
- 37-note slim-key keyboard with polyphonic aftertouch
- Warm and organic, 100% analog signal path
- Intuitive, welcoming knob-per-function layout
- Pro-One style top-panel modulation matrix
- Prophet-lineage resonant filter with bass compensation
- Arpeggiator with sequencer mode
- 128 world-class presets
- Pro-quality, all-steel chassis
Legendary Analog Sound, Reimagined
Fourm delivers four genuine voices of Sequential analog sound, built on the legendary Prophet-5 voice architecture—right down to its envelope response curves. With dual oscillators offering simultaneous wave selection and a classic 4-pole low-pass filter, now enhanced with bass compensation, Fourm captures the warmth and punch that shaped a generation—and takes it to the next level.
A New Fourm of Expression
Fourm’s 37-note slim-key keyboard features polyphonic aftertouch, unlocking expressive techniques like guitar-style note bends, solo voice swells, and other nuanced articulations—completely transforming the experience of playing a modern analog polysynth.
Modulation You Can Touch
Inspired by the Pro~One, Fourm’s top-panel modulation matrix puts deep sound design at your fingertips—no menu diving required. Route sources and destinations with a button press, visualize connections with color-coded indicators, and build complex modulation paths in seconds. It’s fast, intuitive, and designed to keep you in the creative flow.
SPECIFICATIONS
Synthesis
- Oscillators: All oscillators have simultaneously selectable waveforms, including LFO
- Oscillator B: Supports low frequency modes
- Sync: Classic Prophet-style
- Filter: 4-pole resonant lowpass with bass compensation
- Feedback: Aggressive drive circuit
- Envelopes: 2 ADSR envelopes
- Sequencer: Glide per step supported
In/Out
- Main Output: Mono (1/4-inch jack)
- Headphone Output: Mono (1/4-inch TRS phone jack)
- MIDI: In, out, and thru ports
- USB: Bidirectional MIDI communication
- Pedal Input: Footswitch/expression
Power
- Power Switch: Separate
- Power Supply: 12V DC 1.2A, center-positive (included)
- AC Compatibility: 100 V to 240 V at 50 Hz/60 Hz
- Power Consumption: 14 watts maximum
Physical Specs
- Dimensions: 22.13 x 9.88 x 2.75 inches (56.2 x 25.1 x 7.0 cm)
- Weight: 8.76 lbs. (3.97 kg)
- Security: Anti-theft slot
Manufacturer: Sequential
Model: SEQ-3900
SKU: I849276-N-4-WHXX
We are Chuck Levin's Washington Music Center
Since 1958, Chuck Levin’s Washington Music Center has been the trusted destination for musicians and audio professionals across Maryland, Virginia, and Washington, D.C. Family-owned and operated, our legendary music store delivers Everything in Music®—from instruments and recording gear to pro audio, rentals, and repair services.
Our team of musicians and industry experts lives and breathes gear, helping you build the perfect setup for your next performance, studio session, or installation. As an authorized dealer for top brands, we also offer our award-winning CHUCKSCLUSIVE line—exclusive, limited-edition instruments and collaborations recognized with the NAMM Top 100 Dealer Innovation Award for redefining what a music retail experience can be.
Chuck Levin’s isn’t just a store—it’s a community built by players, engineers, and creators who share a lifelong passion for sound. Stop by our legendary Wheaton, MD showroom or contact us anytime for expert advice, product questions, or the best possible deal on your next piece of gear.
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