Temperament has just released the DM7S 137, the successor to their popular DM7 flat-head earbuds. But what exactly has changed? Let's dive deep into the differences between these two reference-grade models.
Introduction: Evolution of Excellence
The original Temperament DM7 earned a loyal following among flat-head earbud enthusiasts for its balanced sound signature and exceptional resolution. Now, with the release of the DM7S 137, Temperament has refined the formula with significant technical upgrades while maintaining the core characteristics that made the DM7 beloved.
Priced at $439.99 USD for the DM7S 137 versus $223.38 USD for the DM7, the new model represents a premium evolution. But is the upgrade worth it? Let's break down the key differences.
Driver Technology: The Heart of the Upgrade
🔬 Driver Comparison
| Feature | DM7 (Original) | DM7S 137 (New) |
|---|---|---|
| Shell Diameter | 16.5mm | 16mm |
| Driver Size | 15.4mm | 15.4mm |
| Diaphragm | Standard polymer | High-polymer with diamond-cut suspension ✨ |
| Magnetic Circuit | Standard | N52 dual linear ⬆️ |
| Voice Coil | Standard aluminum | Ultra-fine aluminum with multi-layer composite ✨ |
What This Means for Sound Quality
While both models share the same 15.4mm driver size, the DM7S 137's driver features significant technological improvements:
- ✅ Patented diamond-cut suspension - Reduces distortion and allows for more precise diaphragm movement
- ✅ N52 dual linear magnetic circuit - Provides more controlled and powerful sound with better damping
- ✅ Multi-layer composite voice coil - Enhanced dynamic energy reserves for improved transient response
Impedance: A Major Change
⚡ Impedance Comparison
| DM7 (Original): | 32Ω - Easy to drive |
| DM7S 137: | 137Ω - Requires quality amplification |
This is perhaps the most significant change between the two models. The DM7S 137's higher impedance means:
Advantages of 137Ω:
- ✅ Better damping and control when properly amplified
- ✅ Lower distortion at higher volumes
- ✅ Improved micro-detail retrieval
- ✅ More refined, nuanced sound
- ✅ Less susceptible to output impedance variations
Considerations:
- ⚠️ Not suitable for smartphone direct connection
- ⚠️ Requires dedicated DAP or desktop amplifier
- ⚠️ Higher barrier to entry for casual listeners
Bottom line: The DM7 was more versatile and easier to drive, while the DM7S 137 is designed for serious audiophiles with proper amplification equipment.
Technical Specifications Comparison
| Specification | DM7 | DM7S 137 |
|---|---|---|
| Shell Diameter | 16.5mm | 16mm |
| Driver Size | 15.4mm | 15.4mm |
| Impedance | 32Ω | 137Ω |
| Sensitivity | 112dB (±3%) | 106dB |
| Frequency Response | 8Hz - 35kHz | 8Hz - 35kHz |
| THD+N | <0.1% @ 1kHz | Not specified |
| Housing Material | Aluminum alloy | 6-series aerospace aluminum-magnesium alloy |
| Cable Material | Silver-plated + refined copper hybrid Litz | Secondary-smelted copper foil Type 2 |
| Cable Plugs | Single plug | Dual plug (3.5mm + 4.4mm) |
| Finish | Standard | Sapphire coating |
Build Quality & Design Improvements
🏗️ Material Upgrades
The DM7S 137 features significant build quality improvements:
- Aerospace-grade 6-series aluminum-magnesium alloy (vs standard aluminum in DM7) - lighter yet stronger
- Sapphire coating process - superior scratch resistance and premium texture
- CNC precision machining with tighter tolerances for better acoustic performance
- Progressive patented ear-conforming structure - improved ergonomics and comfort
🔌 Cable System Enhancement
The DM7S 137 includes a dual-plug cable system:
- ✅ 3.5mm single-ended plug for standard sources
- ✅ 4.4mm balanced plug for balanced-capable DAPs and amplifiers
- ✅ Secondary-smelted copper foil Type 2 wire for improved conductivity
The DM7 features a premium silver-plated + refined copper hybrid Litz cable, which is excellent for its price point but only includes a single plug option.
Sound Signature Comparison
🎵 DM7 (Original) Sound Character
- Balanced performance across low, mid, and high frequencies
- Well-structured soundstage with excellent imaging
- Excellent resolution with full, delicate, and refined details
- Strong imaging capability with outstanding texture
- Exceptional for vocals and classical music
- Natural, smooth presentation that's easy to enjoy
- Best for: Versatile listening, vocals, classical, acoustic music, easy to drive
🎵 DM7S 137 Sound Character
- Rich, warm, and three-dimensional
- Extended frequency response (8Hz-35kHz) with excellent air and sparkle
- Deep bass extension with superior control
- Accurate, focused imaging with natural tonality
- Exceptional soundstage width and depth
- Best for: Critical listening, classical music, jazz, acoustic recordings, audiophile-grade playback with proper amplification
Key Sonic Differences:
| Aspect | Winner | Reason |
|---|---|---|
| Bass Control | DM7S 137 | Better damping with 137Ω |
| Midrange Detail | DM7S 137 | Superior resolution and imaging |
| Treble Refinement | DM7S 137 | Diamond-cut suspension reduces distortion |
| Ease of Use | DM7 | 32Ω much easier to drive |
| Versatility | DM7 | Works with more sources |
| Technical Performance | DM7S 137 | Advanced driver technology |
| Value for Money | DM7 | Excellent performance at lower price |
Price & Value Proposition
| DM7 (Original): | $223.38 USD |
| DM7S 137: | $439.99 USD |
| Price Difference: | +$216.61 (~97% increase) |
Is the Price Increase Justified?
What you get for the extra $216.61:
- ✅ Advanced driver with patented diamond-cut suspension
- ✅ N52 dual linear magnetic circuit (vs standard)
- ✅ Aerospace-grade materials with sapphire coating
- ✅ Dual-plug cable system (3.5mm + 4.4mm balanced)
- ✅ 137Ω impedance for superior control with proper amplification
- ✅ Enhanced technical performance across the board
Our verdict: If you have quality amplification equipment and prioritize ultimate sound quality, the DM7S 137 offers excellent value for serious audiophiles. However, the DM7 at $223.38 represents exceptional value with its balanced sound, excellent resolution, and easy-to-drive 32Ω impedance—making it the smarter choice for most listeners.
Which One Should You Buy?
✅ Choose DM7S 137 if you:
- Own a quality DAP or desktop amplifier
- Prioritize ultimate sound quality and technical performance
- Want the absolute best flat-head earbuds Temperament offers
- Appreciate premium build quality and materials
- Need balanced connectivity (4.4mm)
- Have a budget of ~$440
⭐ Choose DM7 if you:
- Want exceptional value at $223.38
- Need easier-to-drive earbuds (32Ω works with most sources)
- Use portable sources without dedicated amplification
- Appreciate balanced sound with excellent resolution
- Love vocals and classical music
- Value versatility and ease of use
- Are new to flat-head earbuds
- Want premium silver-plated hybrid Litz cable
Final Verdict
The DM7S 137 is not simply an incremental update—it's a significant evolution that targets demanding audiophiles with proper amplification. With its advanced driver technology, higher impedance, premium materials, and superior technical performance, it represents Temperament's flagship flat-head offering.
However, the original DM7 at $223.38 remains an outstanding choice and arguably offers better value for most listeners. Its balanced sound signature, excellent resolution, strong imaging, exceptional vocal and classical music performance, and easy-to-drive 32Ω impedance make it accessible and versatile. The premium silver-plated hybrid Litz cable is also a notable advantage.
🏆 Bottom Line
DM7S 137 ($439.99): Best-in-class sound quality for serious audiophiles with proper gear
DM7 ($223.38): Exceptional value with balanced sound, excellent resolution, and easy versatility
🛒 Shop Temperament Flat-Head Earbuds
Experience reference-grade sound with The HiFi Cat
Shop DM7S 137 ($439.99) →Shop DM7 ($223.38) →Published: January 13, 2026
The HiFi Cat Team
