Why do speakers need time alignment?

When two speakers reproduce the same frequencies but their sound arrives at different times, the waves interfere destructively at some frequencies (comb filtering). At the crossover frequency, even 1 ms of misalignment causes a 3 dB dip. Time alignment eliminates this by delaying the closer speaker so both arrivals are synchronous.

How does SonaVyx find the delay between speakers?

SonaVyx measures the transfer function between the electrical signal and the acoustic output. The impulse response peak position reveals the propagation delay. Cross-correlation provides sub-sample accuracy by interpolating around the correlation peak. The coherence function validates measurement quality.

What is the speed of sound used for delay calculations?

SonaVyx defaults to 343 m/s (1125 ft/s), which is the speed of sound at 20 degrees Celsius at sea level. You can adjust for temperature using the formula v = 331.3 + 0.606T m/s. At 30 degrees C, sound travels at 349.5 m/s, a 2% difference that matters for long throw distances.

How accurate does delay alignment need to be?

For main-to-subwoofer alignment, accuracy within 0.5 ms is sufficient because the crossover frequency is low (80-120 Hz). For main-to-delay speaker alignment at higher crossover frequencies, accuracy within 0.1 ms is needed. SonaVyx achieves better than 0.02 ms resolution via sub-sample interpolation.

Should I delay the main speaker or the fill speaker?

Always delay the closer speaker to match the arrival time of the farther speaker. You cannot make sound arrive earlier, only later. If the main PA is 30 meters away and the delay speaker is 15 meters away, add delay to the fill speaker equal to the distance difference divided by the speed of sound.

What is comb filtering and how does delay alignment prevent it?

Comb filtering creates a series of peaks and nulls in the frequency response when two copies of the same signal arrive at different times. The first null occurs at f = 1/(2*delay). A 1 ms offset creates a null at 500 Hz. Time alignment removes the offset, converting destructive interference into constructive summation.

Can I use delay alignment for subwoofer integration?

Yes, subwoofer time alignment is critical. Measure the delay from the main speaker and subwoofer separately at the crossover region. Set the sub delay so its arrival matches the main speaker. Then verify by measuring with both active, checking for smooth magnitude through the crossover frequency (typically 80-120 Hz).

How does temperature affect speaker delay alignment?

Sound speed increases about 0.6 m/s per degree Celsius. Over a 50-meter throw, a 20-degree temperature change shifts arrival time by approximately 1.7 ms. For outdoor events where temperature changes significantly between soundcheck and show, re-verify alignment before the performance begins.

Why do speakers need time alignment?

When two speakers reproduce the same frequencies but their sound arrives at different times, the waves interfere destructively at some frequencies (comb filtering). At the crossover frequency, even 1 ms of misalignment causes a 3 dB dip. Time alignment eliminates this by delaying the closer speaker so both arrivals are synchronous.

How does SonaVyx find the delay between speakers?

SonaVyx measures the transfer function between the electrical signal and the acoustic output. The impulse response peak position reveals the propagation delay. Cross-correlation provides sub-sample accuracy by interpolating around the correlation peak. The coherence function validates measurement quality.

What is the speed of sound used for delay calculations?

SonaVyx defaults to 343 m/s (1125 ft/s), which is the speed of sound at 20 degrees Celsius at sea level. You can adjust for temperature using the formula v = 331.3 + 0.606T m/s. At 30 degrees C, sound travels at 349.5 m/s, a 2% difference that matters for long throw distances.

How accurate does delay alignment need to be?

For main-to-subwoofer alignment, accuracy within 0.5 ms is sufficient because the crossover frequency is low (80-120 Hz). For main-to-delay speaker alignment at higher crossover frequencies, accuracy within 0.1 ms is needed. SonaVyx achieves better than 0.02 ms resolution via sub-sample interpolation.

Should I delay the main speaker or the fill speaker?

Always delay the closer speaker to match the arrival time of the farther speaker. You cannot make sound arrive earlier, only later. If the main PA is 30 meters away and the delay speaker is 15 meters away, add delay to the fill speaker equal to the distance difference divided by the speed of sound.

What is comb filtering and how does delay alignment prevent it?

Comb filtering creates a series of peaks and nulls in the frequency response when two copies of the same signal arrive at different times. The first null occurs at f = 1/(2*delay). A 1 ms offset creates a null at 500 Hz. Time alignment removes the offset, converting destructive interference into constructive summation.

Can I use delay alignment for subwoofer integration?

Yes, subwoofer time alignment is critical. Measure the delay from the main speaker and subwoofer separately at the crossover region. Set the sub delay so its arrival matches the main speaker. Then verify by measuring with both active, checking for smooth magnitude through the crossover frequency (typically 80-120 Hz).

How does temperature affect speaker delay alignment?

Sound speed increases about 0.6 m/s per degree Celsius. Over a 50-meter throw, a 20-degree temperature change shifts arrival time by approximately 1.7 ms. For outdoor events where temperature changes significantly between soundcheck and show, re-verify alignment before the performance begins.

Speaker Delay Calculator & Finder

Speaker delay alignment ensures that sound from multiple loudspeakers arrives at the listening position simultaneously, preventing comb filtering and improving clarity. SonaVyx measures propagation delay between speakers using cross-correlation analysis of the transfer function impulse response, automatically calculating the required delay in milliseconds for time alignment with sub-sample accuracy.

Try It Now

Open the delay finder in transfer function mode — measure speaker alignment in real time.

Open Tool

Technical Specifications

Parameter	Value	Standard
Detection Method	Cross-correlation peak finding	AES-2id:2023 compliant
Resolution	< 0.02 ms (sub-sample interpolation)	48 kHz sample rate
Distance Conversion	ms to meters/feet at 343 m/s	20 C at sea level
Temperature Compensation	Adjustable speed of sound	v = 331.3 + 0.606T m/s
Maximum Delay	> 500 ms (170+ meters)	FFT size dependent
Coherence Validation	Measurement confidence indicator	AES-2id clause 6
Processing	Rust WASM (client-side)	Real-time capable

How to Find Speaker Delay

Set Up Two-Channel Measurement

Connect the system output as the reference signal and a measurement microphone as the measurement signal. SonaVyx uses the transfer function mode to compute the cross-correlation between these two signals.

Position the Microphone

Place the measurement mic at the listening position where you want to align the speakers. This is typically the mix position, front of house, or the point where coverage from two speaker zones overlaps.

Measure the First Speaker

Mute all speakers except the first one. Start the measurement in transfer function mode. SonaVyx computes the impulse response and identifies the propagation delay from the cross-correlation peak. Record this value.

Measure the Second Speaker

Mute the first speaker and unmute the second. Repeat the measurement. The difference between the two delay values is the time offset that needs compensation via the delay processor in the speaker management system.

Apply and Verify

Set the delay on the closer speaker (or the speaker with less propagation delay) to match the arrival time of the farther speaker. Re-measure with both speakers active to confirm improved coherence and flat magnitude response at the crossover region.

Understanding Speaker Time Alignment

Sound travels at approximately 343 meters per second in air at 20 degrees Celsius. This means a 10-meter difference in speaker-to-listener distance creates a 29 ms arrival time offset. At frequencies above 500 Hz, this offset is long enough to cause significant comb filtering, with deep nulls exceeding 20 dB at specific frequencies. The transfer function measurement reveals these nulls clearly in the magnitude display.

Cross-Correlation Delay Detection

Cross-correlation mathematically slides one signal past another, computing the similarity at each offset. The offset producing maximum correlation is the propagation delay. SonaVyx computes this in the frequency domain using the inverse FFT of the cross-spectral density, achieving O(N log N) efficiency. Sub-sample interpolation around the peak provides resolution finer than one sample period.

Practical Delay Alignment Scenarios

The most common alignment scenarios are main-to-subwoofer (matching sub and top arrival at the crossover region), main-to-delay (synchronizing front-fill or under-balcony speakers with the main PA), and left-to-right (ensuring stereo image integrity at off-center positions). Each scenario has different accuracy requirements based on the crossover frequency where the speakers share content.

Distance Formula and Temperature

The delay in milliseconds equals distance in meters divided by the speed of sound times 1000. The speed of sound depends on temperature: v = 331.3 + 0.606T meters per second, where T is temperature in Celsius. Humidity has a much smaller effect (less than 0.5% variation) and is typically ignored. For outdoor events, measure alignment at show time temperature for best results.

Delay Finder Comparison

Feature	SonaVyx	Smaart v9	REW	OSM
Auto delay detection	Yes (cross-correlation)	Yes (IR peak)	Yes (IR)	Yes (IR)
Sub-sample accuracy	Yes (interpolated)	Yes	Yes	Sample only
Distance calculator	Yes (with temp)	No	Yes	No
Browser-based	Yes	No	No	No
Coherence display	Yes	Yes	Yes	Yes
Multi-speaker workflow	Guided	Manual	Manual	Manual
Price	Free	$898	Free	Free

Frequently Asked Questions

Related Tools & Resources

Transfer Function

Full magnitude and phase measurement

Polarity Checker

Verify speaker polarity before alignment

Crossover Calculator

Calculate crossover frequencies for alignment

Delay (Glossary)

Propagation delay and alignment concepts

Standards References

AES-2id:2023 — AES information document for room impulse response measurement (delay extraction)
IEC 60268-5:2003 — Sound system equipment: Loudspeakers (propagation delay specifications)
AES56-2008 — AES standard on acoustics: Sound source modeling (distance and delay)