Equipment

Measurement

Measurement

Acoustical measurements can be tricky. Take your time to make yourself familiar with the equipment and its use. A precision microphone usually comes with a correction file, allowing measurement precision enhancements. A good option is the microphone offered by Audiovero. I have made very good experiences with microphones provided by iSEMcon.

You do also require a multi-channel soundcard for the measurements. As always, there’s plenty of choice. The ones produced by Focusrite have served me well.

Playback

Playback

When processing up to eight channels with 256k-filters in high resolution a powerful computer (with Intel i7 or i9) is required. The aim is low latency. Under full load, the latency can be reduced to less than 150µs. With a conventional Windows 10 PC this is difficult to achieve. Using a Windows Server 2019 installation with driver optimization is a solid way to success. Make sure to select an appropriate main board. Mostly those populated with Intel LAN chipsets allow for low latency. M.2 SSDs are a must, because they will permit to skip the power spikes in eSATA drives and are in general up to 10 times faster. Use caution in updating to the latest BIOS. Before installing any operating system, enter into the BIOS and disable all C-states and all functionality which is meant to reduce power of the processor or other chipsets. Install or update all drivers. In case of doubt, measure latency (using LatMon) with the old or default driver versus any update. Take your time. Measure it! Do not install any accessory packages which come with the drivers, only the drivers themselves.


The final optimization could be done manually or automated using Audiophile Optimizer. Windows Server does come with a GUI and is mostly compatible with all driver, which were originally designed for use with Windows 10.

A viable alternative is the use of Linux OS for audio. However, before choosing Linux make sure that the required drivers are available in a recent Linux version.

Conversion & Amplification

Conversion & Amplification

What you need to get your six (or 4-8) ways convoluted audio streams into the analogue domain is a multi-channel digital-to-analogue converter. As always, there is plenty of choice!

An excellent and reasonably priced one is the Okto Research DAC8-Pro. Its performance is one of the best for any multi-channel DAC currently available in the market. It’s easy to interface via USB to your DAW. Make sure that you use quality ASIO drivers such as those from DIYINHK or even WASAPI.

A strong recommendation goes to the product range from Merging Technologies. This is the leading manufacturer of high-end studio equipment, satisfying even the highest possible standards. The HAPI is an ultra-performance device and comes with a convenient volume control (with a knob on the front plate). It does interface with any DAW via Ravenna. In comparison to USB, the AES67 interface comes with the PTP clocking system, which is the currently best possible way to transmit audio with low jitter and maximum flexibility.

If you find the HAPI is too complicated, just have a look at the Merging ANUBIS (up to 8 channels) instead.

Now let’s get to the amplifiers. The good news: You have got plenty of power amplifiers to choose from. The bad news: In A 3-way loudspeaker-system requires six amplifiers.

It is strongly recommended that you use powerful amplifiers driving your bass chassis. Class-D-Amps work fine. For the mid-range drive unit and the tweeter, just chose what you like or what is available in your collection. Important is not to swap the amplifiers after the final measurement (or repeat the measurement) in order to preserve the relative volume levels used for the measurements.

A final comment on cost: Given the outstanding performance you could achieve with this concept, the cost of the equipment is small by any Hi-fi or even High-end audio standards.

Again: Enjoy!