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ZOOM TAC-2R Thunderbolt Audio Converter


Do you play guitar and have vocals coming in at the same time? Do you need to record them together in perfect sync? Usually, perfect sync is hard to achieve but one can get the minimum delay. Most of the low latency recording devices come at a high cost and the cheap ones use cheap, slow components that increase the delay and can cause the two to go out of sync. Usually the delay arises in the analog to digital conversion process, but that does not matter because the delay for both the channels will be equal. Both channels will be acquired at the same time and the data will be stream serially (one bit at a time) to the computer. The issue of latency comes in this serialization part where the device must transfer the data fast enough in minimum period of time. Current USB standard has the capability to transfer the data fast enough, but still it is not as fast as the Thunderbolt, which offers minimum serial transfer latency.

The problem

The problem of latency usually becomes apparent not while recording the audio because we can easily edit the channels and align them in software, but while mixing the two audio inputs and again taking them out over speakers is where the problem arises. You might have a guitarist playing a string and a vocal artist singing. Suppose your audio needs to pass through your reverb tool on the laptop before coming out on speakers and there is a delay, it will be a huge mess and a lot of “pissing off”. The best option would be to use monitoring headphones connected directly to the output of the audio interface and send out another cable to the laptop for recording the audio. You can do whatever you want to with your recording, but it won’t feel as dynamic as having a low latency audio interface and having real time mixing and effects applied to your music.

How Zoom fixed it

Zoom TAC 2R comes with a Thunderbolt port which can have transfer speeds up to 10Gbps or more. Faster speeds mean lower latency and thus the Thunderbolt based Zoom TAC 2R offers less than 1 ms latency which becomes almost real-time audio recording.


Thunderbolt Tac-2r frontThe Zoom TAC 2R comes with an aluminium face plate with microphone input connections and cool looking blue LED indicators. There is a smoothly rotating output volume knob for obvious purpose. There are also two gain knobs for adjusting the gain of each individual channel. Additionally, there are two green LED indicators which light up when the input signal gets clipped while passing through the pre-amplifier. If the LEDs flicker just too much, you might want to reduce the gain. Clipped signal produces distorted audio.

On the other side, we have two MIDI ports for interfacing your synthesizer, electronic guitar or whatever.

zoom tac-2r back

All these inputs finally converge into one single Thunderbolt port which can be connected to your computer. At present, all Apple Macs come with the Thunderbolt port by default, so Apples users would have no problem, but for the PC users, you will have to buy a thunderbolt PCI card which plugs on to your motherboard.

The edges on the TAC 2R are curved and the top and the bottom are covered with a slightly glossy, and slightly matte finish metal plates which screw on the sides. The TAC 2R is a rack mount type model, whereas the TAC 2 has similar features or perhaps identical features except that it is a desktop model with the control knob on the top side.

Audio features

The TAC 2R can sample audio at 192kHz with resolution of 24 bits, which is basically professional grade recording. There is an up sampler which over samples the audio at the time of acquisition to prevent aliasing of any signal. This is useful to reproduce or record the treble frequencies. Having the sampling frequency almost twice the minimum audio signal is not enough to accurately represent the treble. We will end up with lot of distortion and that is undesirable when it comes to professional grade audio. Hence, by having sampling frequency which is multiple times higher than the maximum audio signal will help us reduce that distortion which might occur in the treble region.

Tac-2r audio converter

The audio output comes from high quality digital to analog converter which works at the sample sampling frequency of 192kHz max and has 24 bits resolution.

Practically, to have such high sampling frequency and high resolution we require good quality chipset and that takes its toll on the power consumption. It is somewhat difficult to have an entire audio interface with such high specs to run on 2.5Watts of power supplied by the USB port. Hence, the thunderbolt port comes to rescue. It provides 10Watts of power with 18V DC voltage.

According to ZOOM, this higher power has allowed them to use Burr Brown PCM4202 ADC and AKM AK4396 DAC chips. The datasheet shows that the PCM4202 utilises only 375mW max power, whereas the AK4396 uses 200mW max. The total consumption of both the chips is way below 2.5W mark.

Further digging into the datasheet, I found out that the “clipped signal” indicator or the green LEDs are directly connected to the PCM4202 which happens to make the LED turn ON when the input signal touches maximum limit. Additionally, the ADC as well as the DAC has its own digital filters for enhancing the audio, but it will be difficult to say whether ZOOM has chosen to use those or have applied a custom solution for signal conditioning.

The software

Just like the TAC-2R, its software is outstanding. It has a lot of features that a music enthusiast would want to have. The TAC-2 MixEfx has a nicely laid out GUI which is quite self-explanatory with symbols here and there that make it look neat. The GUI has 4 parts, the input pre-amp, the mixer, the sampling frequency and the output controls. The MixEfx literally allows you to change each and every setting on the TAC-2R through software. You can change the gain, the filter settings, input impedance and has a bar graph display constantly letting you monitor the input audio.
TAC-2R_MixEfX software

Then you can also change the sampling frequency and even configure audio routing options. For example you can configure a loop back or directly pass the audio to the DAC for output monitoring and so on. Finally, there are effects such as reverb, echo and stuff like that. Oh, you can also change the output signal volume through this software. As always, there is a provision for saving the settings in a file.


Considering the ZOOM TAC-2R hardware, the software and all the amazing features they both have, I have to admit that it is a nice little audio interface for any music enthusiast, be it professional or amateur. The ZOOM TAC-2R will not let you down.

If you are working with a larger group of musicians, you can also check out equally great 8 channel model where one actually gets to praise the low latency and high bandwidth of the Thunderbolt port.

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United States: Amazon, Bhphotovideo

United Kingdom:  Gearsformusic




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Great sound, and easy to set up and use. Sound quality is superb. The software effects and mixer installed easily and has given neither of my systems any trouble! Rack-mounted design offers a more ‘one dial per function’ approach. MixEfx software expands TAC-2R’s feature set and is well designed.


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• 2-in/2-out high speed Thunderbolt™ audio interface
• Support for recording and playback up to 24-bit/192kHz
• Ultra-low latency audio streaming
• Two combo balanced XLR/TRS input connectors accept both mic and line-level signal
• Hi-Z switches allow direct connection of electric guitar or bass
• Switchable +48V phantom power
• Two balanced TRS output jacks for connection to amplifiers or self-powered speakers
• 1/4″ headphone jack with dedicated level control
• Independent gain controls and clip LEDs for each input
• Large knob output volume control
• Direct Monitoring switch for zero latency monitoring in mono or stereo
• MIDI In and Out
• High-performance mic preamps with up to +60dB of amplification
• 4x upsampling during A/D and D/A conversion for reduced noise and enhanced fidelity
• Asynchronous transfer system unaffected by computer jitter
• Bus powered—no AC power required
• Robust metal housing ensures roadworthiness
• Works with all Thunderbolt-equipped Macintosh computers running OS X 10.8.5 or later


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A compact, high quality audio interface that has super low latency and professional quality audio I/O.
Sound quality90
Worth it?90
Reader Rating13 Votes82
Low latency, almost realtime interface
High resolution input and output
Sturdy build that looks nice
Easy to use
Analog as well as digital (MIDI) input
Useful and powerful software that has deep integration with the hardware
A little on the expensive side
    1. Did a bit of research, it does work but it seems there are some issues in that area, i’ll quote the relevant information below.

      “Zoom wrote me, the TAC-2(R) sends always SysEx Messages thru the OS X. The reason is horrible simple. The Audiosoftware MixEfx needs the SysEx Data to communicate between Hard and Software. You don’t have any chance to stop this problem. You will receive the SysEx Data.

      The next step/problem is when you record midi notes with you master keyboard then you record the SysEx data too. It sucks. The only way to eliminate the SysEx Horror is to set the SysEx Filter in the Projectsettings and disable the midi monitor in the transport window. ”

      Source: http://www.logicprohelp.com/forum/viewtopic.php?f=1&t=108171

  1. 67

    Recommended audio interfaces:

    ZOOM UAC-2 USB 3.0
    $299 , June 2015
    1.8 msec overhead round trip latency
    2.2 msec round trip @ 96 kHz / 32 samples

    ZOOM TAC-2R Thunderbolt (More than twice as fast as USB 3.0)
    $320 , December 2014
    1.8 msec overhead round trip latency
    2.2 msec round trip @ 96 kHz / 32 samples
    Latency time in the TAC-2R is just 4.17 msec round trip when operating at a 44.1kHz sampling rate with a 64 sample buffer size.

    USB 3.0 has a much lower latency than USB 2.0

    The USB 3.0 improves upon communication model and reduces transmission latency by minimizing polling, lowering CPU usage, and allowing devices to transmit data as soon as it is ready.

    USB 3.0: 1.3-1.8 msec overhead latency……750 iops
    USB 2.0: 4-6 msec overhead latency…………200 iops

    Actually, additional 6ms latency (18ms round-trip latency at 512 samples 44khz) is too much for piano players and also for music producers which have a huge volume of virtual instruments that have dedicated audio effects.

    If you assign 256 samples into buffer, you have 6ms output latency at 44khz (256 / 44100 = 0.0058 sec => ~6ms) and therefore you have 12ms latency in output trough USB 2.0 and 7.3ms latency trough USB 3.0!

    I can’t produce orchestral music or even playing Piano over than 13ms round trip latency. In worst case scenario I need to set buffer to 512 samples due to a large project and this cause to have around 13ms round-trip latency and therefore I strongly recommend that use professional PCIe sound cards such as RME AIO instead of USB 2.0 audio interfaces or going with ZOOM TAC-2R which has ultra low-latency trough USB 3.0.

    Sound quality user85
    Worth it? user92
    Features user92

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