About digital stereo amp latency

[jamius19]

Hi everyone,

I'm an audio gear newbie who's looking into passive speakers to connect to my Focusrite Scarlett 2i2 (3rd Gen) to minimize latency for live monitoring.

For amplification I was looking into the Fosi Audio TB10D. It uses the TPA3255 chip and is a digital amp.

It's my understanding that once audio leaves my interface, the only way latency can be added is via this amp as passive speakers should not add any latency.

Now my question is if I use this amp with passive speakers, how much latency can I expect from this kind of digital amplifiers (and not from other factors like PC/Interface)?

Thanks for any help!

[James Perrett]

For amplification I was looking into the Fosi Audio TB10D. It uses the TPA3255 chip and is a digital amp.

It is not a digital amp. It is a class D amplifier which is fully analogue apart from a little control logic which is not in the audio path.

[Hugh Robjohns]

It uses the TPA3255 chip and is a digital amp.

No such thing (not in audio, anyway). It's an analogue amp that operates in Class-D. It has negligible latency.

Amp classes just determine how energy from the power supply is passed through to the speaker — how the output devices are configured and operate.

Class-D switches them fully on or off very quickly at a high frequency. This minimises the power each device has to handle at any moment in time, and makes the amp very power efficient. The more time the output devices are switched on, the more energy is passed to the speaker (and vice versa).

A low pass filter removes the switching artefacts, but it really is a fully analogue technology.... despite the moronic marketing bollarks.

It's my understanding that once audio leaves my interface, the only way latency can be added is via this amp as passive speakers should not add any latency.

Not strictly true. Most speakers introduce a small amount of latency at low frequencies due to the crossover and cabinet designs....

Now my question is if I use this amp with passive speakers, how much latency can I expect from this kind of digital amplifiers...

None that you'll notice.

Most of the overall latency will be due to the DAW/driver buffers, and that should be very small — typically a couple of milliseconds. There'll also be around a millisecond or so from the interface's A-D and D-A conversion.

That power amp is of no concern as far as latency goes.

[Folderol]

Also keep in mind there is about 1mS latency for every 30cm between you an the speakers.

[BigRedX]

Also keep in mind there is about 1mS latency for every 30cm between you an the speakers.

But, our brains are very good at telling the difference between sound that is delayed because it is a physical distance away and sound that has been delayed that has no distance information. That's why even small latency values can be a problem for some people. It's also important to take into account the cumulative effects of multiple latencies from each device.

However in this case the amp is very unlikely to be adding any noticeable latency to the signal.