Ripa er synlig, men lydkvaliteten er god.

Because ripa is the definite singular form of ei/en ripe.

• ei/en ripe = a scratch
• ripa = the scratch

Norwegian usually puts the definite article on the end of the noun instead of using a separate word like the.

That -a ending shows a feminine definite form in Bokmål.

The noun ripe is often treated as feminine:

• ei ripe = a scratch
• ripa = the scratch

In Bokmål, many feminine nouns can also be used as common gender, so some speakers may also say en ripe / ripen. Both patterns are possible, but ripa is very natural.

Because Norwegian usually writes compound nouns as one word.

lydkvaliteten breaks down like this:

• lyd = sound
• kvalitet = quality
• -en = the

So:

• lydkvalitet = sound quality
• lydkvaliteten = the sound quality

English often uses separate words where Norwegian prefers a compound.

Because the sentence is talking about the sound quality of a specific thing already being discussed.

So lydkvaliteten er god means the sound quality is good, not just sound quality is good in a general sense.

This is very natural in Norwegian when describing one particular object, such as a record, CD, or speaker.

They are both predicate adjectives, meaning they come after er and describe the subject.

In Norwegian, predicate adjectives agree mainly with gender and number, but they do not take a special definite form just because the noun is definite.

So here:

• Ripa er synlig
• lydkvaliteten er god

Both subjects are singular, so these adjective forms are correct.

For comparison:

• Ripene er synlige = The scratches are visible
• Høyttalerne er gode = The speakers are good

Because the sentence has two full clauses joined by men:

• Ripa er synlig
• men lydkvaliteten er god

Each clause needs its own finite verb, and here that verb is er.

You cannot normally leave out the second er.

After men (but), Norwegian usually starts a new main clause with normal main-clause word order.

So you get:

• men lydkvaliteten er god

That is, subject + verb.

This is different from cases where another element is placed first and triggers inversion, for example:

• I dag er lydkvaliteten god = Today, the sound quality is good

But after men alone, you normally just continue with ordinary word order.

Yes, in standard Norwegian it is normal to put a comma before men when it links two clauses like this.

So:

• Ripa er synlig, men lydkvaliteten er god.

That comma is the expected punctuation.

Yes, in Bokmål you may hear or see both, depending on gender choice:

• ei ripe → ripa
• en ripe → ripen

The version in your sentence uses the feminine form ripa. That is perfectly normal.

Here god means good in quality, not morally good.

Norwegian god is a very broad adjective. Depending on context, it can mean things like:

• good
• nice
• tasty
• kind
• skilled

In lydkvaliteten er god, it specifically means the sound quality is good.

Yes, but the meaning changes a little.

• lyden er god = the sound is good
• lydkvaliteten er god = the sound quality is good

lydkvaliteten is a bit more specific and technical. It focuses on the quality of the audio, not just the sound in a general sense.