A acústica tem muito eco.

Because acústica is being used as a specific noun here, so Portuguese normally uses the definite article: a.

• a = the for a feminine singular noun
• acústica = acoustics / the acoustic quality

So A acústica tem muito eco is literally something like The acoustics have a lot of echo.

In Portuguese, articles are often used more than in English, especially with nouns used in a general-but-still-identifiable way.

Because acústica is a feminine noun in Portuguese, so it takes a and not o.

• a acústica
• not o acústica

This also affects any adjectives or other words that might agree with it in a larger sentence.

A practical tip: many nouns ending in -a are feminine, and acústica follows that common pattern.

Tem is the he/she/it form of ter, which usually means to have.

So:

• tem = has

In this sentence, a acústica is the subject, so Portuguese says:

• A acústica tem muito eco.
• literally: The acoustics have a lot of echo.

This is natural Portuguese, even if English might prefer something like The room is very echoey or There’s a lot of echo in the acoustics depending on context.

Portuguese often uses ter to describe what something contains or what quality it has.

So:

• tem muito eco = has a lot of echo

This is a very common Portuguese way to express this idea. English often uses different structures, such as:

• It’s very echoey
• There’s a lot of echo
• The acoustics are echoey

But in Portuguese, ter sounds very natural here.

Here, acústica refers to the acoustic quality of a place or environment — basically, how sound behaves there.

So it does not mean the academic subject acoustics in this sentence. It means something more like:

• the acoustics
• the sound properties of the room/place

For example, this sentence could be said about:

• a room
• an auditorium
• a church
• a hall
• a studio

Because Portuguese commonly uses acústica in the singular to talk about the acoustic quality of a place.

So even though English often says the acoustics (plural form), Portuguese can say:

• a acústica

This is one of those cases where you should not translate word-for-word by number.

Here muito means a lot of.

• muito eco = a lot of echo

Since it comes before a noun, muito is working like a quantity word.

Compare:

• muito eco = a lot of echo
• muita reverberação = a lot of reverberation

Notice that muito changes form to match the gender and number of the noun when it works like this:

• muito eco (masculine singular)
• muita acústica ruim would be unusual, but grammatically feminine singular
• muitos sons
• muitas caixas

Because eco is being treated as an uncountable idea here, like echo in English when you mean the general presence of echo.

So:

• muito eco = a lot of echo

This sounds more natural than pluralizing it.

You can say ecos when talking about separate echoes:

• Ouvi vários ecos na caverna.
• I heard several echoes in the cave.

But in A acústica tem muito eco, the idea is general, so singular is the natural choice.

In standard modern Brazilian Portuguese, eco is usually masculine:

• o eco
• muito eco
• um eco forte

So in this sentence, muito is masculine singular because it refers to eco.

The stress is on cús because of the accent mark:

• a-CÚS-ti-ca

A rough Brazilian Portuguese pronunciation is:

• ah-KOOS-chee-kah or ah-KOOS-tee-kah, depending on accent

A more IPA-like version for many Brazilian accents is:

• [aˈkus.tʃi.kɐ]

Important points:

• ú shows the stressed syllable
• in many Brazilian accents, ti before a vowel can sound a bit like chee

In Brazilian Portuguese, eco is usually pronounced roughly like:

• EH-ko

IPA:

• [ˈɛ.ku]

The first syllable is stressed:

• E-co

Yes. Some natural alternatives are:

• Tem muito eco. = There’s a lot of echo.
• A sala tem muito eco. = The room has a lot of echo.
• Esse lugar tem muito eco. = This place has a lot of echo.
• A acústica é ruim. = The acoustics are bad.
• A acústica está com muito eco. = The acoustics have a lot of echo. / The sound is very echoey.
• Há muito eco. = There is a lot of echo. (more formal/literary)

The original sentence is fine, but in everyday conversation people may often mention the place directly, like a sala or esse auditório.

Yes, it is understandable and natural, especially in contexts where people are specifically talking about sound quality.

That said, in casual conversation, Brazilians might more often say something like:

• Tem muito eco aqui.
• Essa sala tem muito eco.
• Esse lugar dá muito eco.
• A acústica aqui é ruim.

So the sentence is good Portuguese, but the most natural choice depends on the situation.

Both can express the idea that there is a lot of echo, but they feel different.

• tem muito eco = very common in spoken Brazilian Portuguese
• há muito eco = correct, but more formal and less common in everyday speech

In Brazil, ter often replaces haver in everyday language when meaning there is/there are.

So in conversation, people are much more likely to say:

• Tem muito eco aqui.

than

• Há muito eco aqui.

Yes. Depending on context, acústica can refer to:

1. acoustics as a field of study

   • Ela estuda acústica.
   • She studies acoustics.

2. the acoustic quality of a space

   • A acústica do teatro é excelente.
   • The theater’s acoustics are excellent.

3. In some contexts, violão acústico uses acústico/acústica in the sense of acoustic rather than electric, but that is an adjective, not this noun use.

In your sentence, it is clearly the second meaning.

Yes. A very common sentence is:

• A acústica é ruim.

That means:

• The acoustics are bad.

Other useful examples:

• A acústica é ótima. = The acoustics are great.
• A acústica não ajuda. = The acoustics don’t help.
• A acústica deste salão é péssima. = The acoustics of this hall are terrible.

So acústica is a very useful noun for talking about sound quality in Portuguese.