Reply To: How to import Magnitude only .txt files?

[EA Support]

EA Support

3 June 2025 at 12:29 pm #1053

Hi richardsllc,

I’ve receive the files and looked them over. Here’s some initial thoughts.

I had assumed that you had obtained magnitude and phase measurements of the processing for an existing EV preset, and that you were trying to replicate this processing using IIR, FIR or IIR+FIR. (This is very straight forward with FIR Designer M and a safe path for getting a good result, benefiting from all the manufacturers expertise.) However the files appear to be individual driver measurements of a cabinet (or cabinets).

Before I talk about the FIR Designer M system files, I need to talk about making presets. Designing multi-way presets, particularly for pro audio cabinets, involves optimising many factors including response on axis, response in different directions within a desired coverage angle, consistency of directivity across frequency, and system robustness at high levels. For example a DSP design which gives a good on axis response at low levels could damage a driver at high levels or (if using limiters) cause some drivers to limit earlier than others (causing dynamic fluctuations in response and directivity). This may then require moving crossovers higher in frequency – to reduce the burden on the MF or HF – which then affects directivity, and so on, and so on. All this to say, I would be very nervous trying to make a preset from on axis measurements, without having the ability to measure the system at other angles (e.g. using a turntable or multi-axis robotu) and without being able to test at high levels (and be willing to burn drivers).

Anyway… regarding your FIR Designer M system file.

IMPORT tab

The measurements you provided all have a time offset of roughly 9.5ms but the offsets are not all the same. Were the measurements captured with a common timebase, or are they completely independent? The slight time delay differences seem to match the different physical depths of the drivers from a XVLS photo I found online, but it’s important to be sure. If they weren’t captured with a common timebase, then you will need to take more measurements.

In FIR Designer M, the ~9.5ms delay is present in the loaded measurements in each channel. If you remove this delay, much of the high phase slope goes away, making the workflow easier. For example, on the Import tab “Delay Adjustment” “Delay: samples” to -458 samples.

For each channel, turn on “Hide phase” and for LF set “>” to 1000 Hz, for MB set “>” to 5000 Hz and for HF set “<” to 200 Hz. Now the magnitude and phase plots become easier to view as you work through the workflow.

GAIN/POLARITY/DELAY tab

All channels have some non-zero delay. The G/P/D tab is about adjusting the alignment between the channels. Any delay common to all channels is just bulk delay added to the whole system, which isn’t necessary and can be removed.

IIR FILTERS and FIR tabs

There are IIR HPF and LPF filters enabled AND HPF and LPF filter prototypes enabled on the Mag Adjust tab. These are causing major problems with the preset. Choose one or the other, but not both. Generally HPF and LPF filters are more efficient and effective as IIR filters, leaving the FIR to deal with more delicate mag and phase adjustment. If you definitely want linear-phase crossover HPF and LPF’s, then turn off the HPF and LPF filters in the IIR filters tab.

The Auto-phase that is enabled on the HF is unnecessary. It’s just trying to undo bulk delay and wasting FIR taps.

I have just emailed you two new systems. One is IIR only and the other is FIR only. Please study them carefully in terms of how to use the workflow, but don’t rely on the actually settings… see the “Before..” paragraph above. 🙂 Our support is focused on how to use the software.

Regards,
EA Support