[PA] First direct box DI

Hello. This is Yoshitaka posting here.
I've been recording acoustic guitars and basses via a mixer, and I'm still a DTM beginner with only about 4 months experience (as of November 2020), but I bought a direct box (hereinafter DI) from Sound House because I wanted to have a little more feeling.
In addition to the feeling of use, I would like to write about the sense of summarizing the technical terminology that I’ve learned.
I hope that it will help those who are considering purchasing a DI in the future.

1. The main function of DI

The main functions of DI are as follows. This is quoted from the Sound House cheat sheet.

• Impedance conversion
  If the high impedance signal of a passive electric guitar or electric bass that does not use a battery is output to the mixer as is, problems such as high frequency attenuation will occur, so it is converted to a low impedance signal via DI.
• Conversion from unbalanced signal to balanced signal
  The unbalanced signal output from an electric or electronic musical instrument such as an electric guitar is converted into a noise-resistant balanced signal, making it difficult for noise to be generated even when using a long cable.

Quote "What is a DI (Direct Injection Box)?"

2. DI and my impressions from trying one

(1) Passive type

■ dbx / DJDI 2ch passive DI

I purchased this model which can output in stereo because the pickup of the acoustic guitar is a Fishman Rare Earth Blend.
This was my first DI. Through this model, the graininess and sound clarity is improved, and the acoustic guitar sound becomes clearer. However, since it is passive, the output level is lower than that of the mixer. The mixer feed was much better with the 1/2 mic input (XLR-XLR) than with the 3/4 terminal input (XLR-TRS conversion). (Thank you for this advice from the Sound House support staff.)

(2) Active type

■ CLASSIC PRO / CDI-1A Active Direct Box

Used when outputting a passive bass to a mixer. Many of the active types are expensive, so I bought a high cost performance Classic Pro. The outline of the sound is clear and comfortable. There were many articles recommending active DI for high-impedance instruments such as electric guitars and passive basses, so I felt that this was the correct one for me. The mixer also has a HI-Z input, but it feels clearer via DI.

I’m using the above two DIs together, but if possible, it might have been best if I had an active stereo type as well.
However, active stereo (2ch) DIs are quite expensive, so maybe I was right to buy two 1-channel active types.

3. Glossary

I didn't understand these terms at all at first because I had little knowledge of audio. I couldn't understand them because they were used on the premise that I knew the manual, so I looked up the terms. I will add the terms below.

• Attenuator
  A device that attenuates a signal to an appropriate level. Depending on the model, there are both variable types and fixed types. If some attenuation values are fixed, it will have a PAD switch described below. There are cases where a variable attenuator is called a gain volume.
• PAD switch
  A switch that specifies the sound intensity (dB) that can be attenuated. -20dB 0dB, etc. Specifiable values differ depending on the model.
• Low pass filter
  A switch that cuts high-frequency noise. Some models are equipped with a filter for cutting low frequencies.
• 4. Ground lift switch
  If the DI body is in contact with an amplifier, a humming noise may occur due to the power supply. In such a case, turn on this switch (it appears to be the equivalent to disconnecting the first pin of an XLR terminal)

4. Impressions from using DI

I'm grateful for the feeling that a clearer sound can be obtained than when connecting directly to a mixer. But if I take this sound for granted, when I actually get back together with the band, I'm wondering if it's possible to produce such a clear sound via an amplifier (I think it's probably difficult, so I’ll bring a DI when actually resuming live performances. I think it will be sent directly to PA).
I’m also grateful to the reviewers for helping me to select products from the reviews posted on Sound House, even slightly specialized equipment such as the DI. Thank you very much.