La edición reduce el ruido de fondo.

Because edición is a feminine noun. A very useful pattern is that nouns ending in -ción are usually feminine: la edición, la canción, la decisión, la traducción.

So the article has to match:

• la edición
• not el edición

Edición can mean editing or edition, depending on context.

In this sentence, it most naturally means editing as an activity or process, especially if the English meaning shown is something like Editing reduces background noise.

So:

• la edición = editing here
• but in other contexts, una edición could be an edition of a book, newspaper, event, etc.

Spanish uses definite articles more often than English.

Here, la edición and el ruido de fondo sound natural in Spanish because they refer to:

• the general process of editing
• background noise as a concept or the relevant background noise in context

English often drops the in general statements, but Spanish usually keeps it:

• La música ayuda a concentrarse.
• El ejercicio es importante.

So La edición reduce el ruido de fondo is a normal Spanish structure.

Reduce is the third-person singular present tense of reducir.

The subject is la edición, which is singular, so the verb must also be singular:

• la edición reduce

Other present-tense forms are:

• yo reduzco
• tú reduces
• él / ella / usted reduce
• nosotros reducimos
• vosotros reducís
• ellos / ellas / ustedes reducen

A useful thing to notice: reducir is mostly regular in the present tense, except for yo reduzco.

In standard Peninsular Spanish, reduce is pronounced approximately reh-DOO-theh.

A few key points:

• the stress is on du
• the c before e is pronounced like the th in think in most of Spain
• the final e is pronounced, not silent

So it is not pronounced like English reduce.

Yes. Ruido is a masculine noun, so it takes el:

• el ruido

That is something you mostly just learn with the noun itself:

• el ruido
• un ruido
• mucho ruido

Even though -o often signals masculine nouns, it is still best to learn nouns together with their article.

De fondo means in the background or background.

So:

• ruido de fondo = background noise

This is a very common expression. Literally, it is something like noise of background, but in natural English we say background noise.

You will also see de fondo in other phrases:

• música de fondo = background music
• imagen de fondo = background image
• color de fondo = background color

Because Spanish often expresses this kind of relationship with noun + de + noun.

So:

• ruido de fondo
• literally noise of background
• naturally in English: background noise

This is a very common Spanish pattern:

• taza de café = cup of coffee
• mesa de madera = wooden table
• fin de semana = weekend

English often puts the describing noun first, but Spanish frequently uses de.

It is best to learn de fondo as a very common expression meaning background in many contexts.

A word-for-word translation can help you understand it, but it is more useful to remember the whole chunk:

• ruido de fondo = background noise
• música de fondo = background music

So yes, it behaves a lot like a set phrase.

Yes, that would also be correct. Disminuir means to reduce / lessen / decrease.

The difference is mostly about style and nuance:

• reducir is very common for reducing something
• disminuir can sound slightly more like decrease or make less

In many contexts, both work:

• La edición reduce el ruido de fondo.
• La edición disminuye el ruido de fondo.

But reduce is a very natural choice here.

Yes, but the original order is the most neutral and natural:

• La edición reduce el ruido de fondo.

Spanish word order is flexible, but changes often add emphasis or sound less neutral. For example:

• El ruido de fondo lo reduce la edición.

This version emphasizes el ruido de fondo, but it is less straightforward and would usually only be used in a specific context.

For learners, the original subject + verb + object order is the best model.

Because the personal a is mainly used before specific people and sometimes pets or personified beings, not before things.

Here, el ruido de fondo is a thing, so you simply say:

• reduce el ruido de fondo

Compare:

• Veo a María. = I see María.
• Veo el coche. = I see the car.

So no a is needed here.

The stress falls on the last syllable: e-di-CIÓN.

The written accent mark on ó tells you that the stress is there. Without the accent, Spanish pronunciation rules would suggest a different stress pattern.

This is another useful pattern:

• words ending in -ción are stressed on -ción
• edición, canción, traducción, información

So the accent mark is important both for spelling and pronunciation.