Insight

How Voice AI Handles Noisy Calls in Real Indian Conditions

September 19, 20264 min read
FF
Fabian Ferno

Co-Founder and CTO

The demo vs reality gap

Every voice AI vendor shows demos in quiet rooms with clear microphones and standard accents. The accuracy numbers look impressive: 95%, 97%, sometimes higher.

Then you deploy in production and a caller is standing at a bus stop in Hyderabad, speaking Telugu on a Jio network with 70% signal strength, with traffic noise and a street vendor in the background.

That 95% accuracy drops to 60%. Maybe lower.

The gap between demo accuracy and production accuracy is the single biggest reason voice AI deployments fail. Not because the AI is bad. Because it was tested in conditions that do not exist in the real world.

What makes Indian call audio hard

Mobile network compression: The majority of Indian calls come over mobile networks. These networks use aggressive audio compression (AMR, EVS codecs) that removes frequencies useful for speech recognition. The audio your AI receives is not the audio the caller spoke. It is a compressed, lossy version.

Background noise: Indian callers are not sitting in quiet offices. They are calling from marketplaces, bus stands, construction sites, kitchens, and shared workspaces. Background noise is the norm, not the exception.

Connection quality: In rural and semi urban areas, network connectivity can be inconsistent. Packet loss, jitter, and variable bandwidth cause audio dropouts that confuse ASR systems designed for clean input.

Device diversity: Enterprise calls come from everything: flagship smartphones with noise cancelling microphones, five year old budget Androids, feature phones, and landlines. Each device produces dramatically different audio quality.

Dialect variation: Hindi as spoken in Bihar sounds different from Hindi spoken in Rajasthan. Tamil varies between Chennai and Madurai. These are not different languages, but the acoustic differences are enough to confuse ASR models trained on standard speech.

Code switching patterns: Indian callers frequently mix languages within a sentence, and the mixing patterns vary by region, age, and education level.

How to build ASR for these conditions

Noise suppression as a first stage

Before audio reaches the speech recognition model, it passes through a neural noise suppression layer that separates speech from background noise. This is not simple noise gating (which cuts audio below a threshold). It is a learned model that identifies and preserves speech patterns while suppressing non speech audio.

Training on real call data

The most important factor in production ASR accuracy is training data. A model trained on read speech from studio recordings will struggle with spontaneous conversation from a noisy mobile call. ARCA's ASR models are trained on thousands of hours of actual Indian enterprise call recordings across multiple languages, network conditions, device types, and noise environments.

Adaptive decoding

When audio quality drops (packet loss, heavy compression, extreme noise), the ASR system needs to adjust its expectations. Adaptive decoding uses audio quality estimation to modify confidence thresholds and decoding parameters in real time. On clean audio, the system runs with tight confidence thresholds for maximum accuracy. On degraded audio, it widens its beam search and leans more heavily on language model predictions to fill gaps.

Packet loss compensation

When network issues cause audio dropouts, the system uses contextual prediction to estimate what was likely spoken during the missing segment. This works well for short gaps (under 200ms) and gracefully degrades for longer ones.

Multi condition acoustic models

Instead of one model for all conditions, ARCA uses acoustic models trained on specific condition profiles: clean audio, moderate noise, heavy noise, low bandwidth, and feature phone audio. A lightweight classifier selects the appropriate model within the first second of audio.

Measuring real world accuracy

Do not trust accuracy numbers unless you know the test conditions. When evaluating voice AI, ask:

  • What audio conditions were used for testing? (clean studio, simulated noise, real call recordings)
  • What languages and dialects were included?
  • What network conditions were simulated? (4G, 3G, 2G, PSTN)
  • What devices were represented?
  • Was the test set from the vendor's training data, or held out production data?

A vendor reporting 95% accuracy on clean English audio is telling you nothing about production performance in Indian conditions.

ARCA's approach

ARCA's ASR pipeline is designed for Indian production conditions:

  • Trained on 10,000+ hours of real Indian call audio across 22 languages
  • Neural noise suppression as a mandatory first processing stage
  • Multi condition acoustic models selected automatically based on audio quality
  • Adaptive decoding that adjusts to degraded conditions in real time
  • Packet loss compensation for network dropouts
  • Continuous model improvement using production call data (with consent)
  • Production accuracy benchmarked at 85 to 90% across real call conditions, not lab environments

The difference between 60% accuracy and 85% accuracy in production is the difference between a product that works and one that does not.

Frequently asked questions

What is ARCA's accuracy on noisy calls?

On real production calls with typical Indian noise conditions, ARCA maintains 85 to 90% speech recognition accuracy. This is benchmarked on actual enterprise call recordings, not clean audio test sets.

Does audio quality affect which languages work best?

All languages are affected by poor audio quality, but languages with more training data (Hindi, Tamil, Telugu, Kannada, Bengali, English) are more resilient because the acoustic models have seen more examples of degraded conditions. Less resourced languages may see slightly higher accuracy drops in very noisy environments.

Can ARCA work on 2G or PSTN connections?

Yes. The adaptive decoding pipeline and multi condition models handle low bandwidth and PSTN audio. Accuracy will be lower than on 4G or VoLTE calls, but the system remains functional and gracefully escalates to a human agent when confidence drops below threshold.

How does ARCA improve over time on our specific call conditions?

With consent, ARCA uses production call data to continuously fine tune acoustic models for your specific audio conditions, dialect patterns, and vocabulary. Accuracy typically improves by 3 to 5 percentage points in the first 3 months of deployment.

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How Voice AI Handles Noisy Calls in Real Indian Conditions | Tenori Labs