Particle と as a standard of comparison with まで

Referring to the sound of an extreme megaphone:

If it's above ground it is a sound that will reach as far as several tens of kilometres.

I'm pretty confident I've translated this correctly but I don't understand how the と particle is working here.

My guess is that it is being used to mark a standard for comparison. So in really bad English I have "The sound reaches distantly, as much as compared to tens of kilometres".

If my above assumption is true then what happens if I remove まで? My guess is that the sentence becomes ungrammatical. So I can have 地上なら、遠く達する音だ. But neither 地上なら、遠くまで達する音だ nor 地上なら、何十キロと遠く達する音だ make sense on their own.

In summary I feel that the と and まで particles are teaming up in this sentence. To give AとBまで with a meaning "As much as characteristic B when compared to A".

Could I rephrase it as:

Would that be wrong? Have a different feel?

Is my analysis correct? If not please enlighten me.

Edit:

The suggested duplicate explains と. but it leaves me more confused, because I thought まで was playing the part of 'as much as'. What is まで doing? Can it be removed? I still don't understand the overall grammar of the sentence.

• The edit part is a good question but I think you should make another post because it's after all irrelevant to と. – broken laptop Dec 7 '18 at 15:04
• Oh this was reopened already. – broken laptop Dec 7 '18 at 15:11

Now probably you are confused by the series of non-obvious idiomatic expressions. A more literal translation would be:

It is a sound that [should reach [to a distance], [by tens of kilometers]] if on the ground.

So yours is correct as a whole too, but there is no connection between 何十キロと and 遠くまで, as both are independent qualifiers to the verb.

• 何十キロと
As previously pointed out, this と is covered by と after counting something, the way to remind about greatness of the amount. You can actually translate this part alone "as far as tens of kilometers". 何十キロほど just means "some tens of km" or "roughly tens of km", but 何十キロほど would be somewhat close to this.
• 遠くまで
This is noun 遠く "distant place" + postposition まで "till".

To explain 遠く first, we have adverb-looking forms 遠く and 近く as very commonly used nouns (though tend to become adjective in English translations).

電話は遠くに住む人と会話できる By telephone you can talk with people living far away (= in a distant place).

遠くの親戚より近くの他人 Strangers nearby rather than relatives faraway. (A near friend is better than a far-dwelling kinsman.)

On top of this, 遠くまで "up to a distance" should be memorized as if a fixed phrase, since it translates a part of usage of English "far". Why? Because Japanese 遠い is not just "long way" but "separated by a long distance", in other words, "removed by distance in the way two points do not interact". Thus, a phrase like 遠く達する will be, positively saying, poetic, and negatively, unnatural (because it actually reaches the other side). For this reason, 遠くまで is the normal phrase we use to describe something travels "far".

○ 遠くまで来たものだ we've come a long way; we've come this far
○ 遠く（へ／に）来たものだ
× 遠く来たものだ

• I never knew that 遠く could work as a noun. This is the key to understanding. Thanks. – user3856370 Dec 7 '18 at 23:06

と and まで don't really have anything to do with each other here. と～まで isn't a grammar point or some kind of fixed pattern, its just と being used with まで in the same sentence.

Now と has a meaning that is to me pretty close to も, which is:

６ （数量を表す語に付き、打消しの表現を伴って）その範囲以上には出ない意を表す。…までも。「全部で一〇〇円―かからない」「一〇〇キロ―走らなかった」

https://dictionary.goo.ne.jp/jn/154670/meaning/m0u/%E3%81%A8/

So basically it means that the 遠く will not go beyond 何十キロ.　(not more than)

As for まで:

１ 動作・事柄の及ぶ距離的、時間的な限度・範囲・到達点を表す。「ここ迄来れば安心だ」「明日迄待ってください」「東京から大阪迄三時間かかる」

It focuses much more on the distance between an implied point A, and the point B marked with まで. (until)

So (at least to me), it literally means:

And:

Feels ungrammatical

Since it seems like the question about the と was resolved, I'll just comment about the まで.

I think the use of まで in the original sentence simply expresses to a certain extent, similar to the phrase "空港までお願いします” (which you could say to a Taxi driver).

Regarding your replacement with ほど, I feel that (based on this post which I had asked) も and と can be used with uncertain amounts, whereas ほど to me does not feature natural in that case. In other words, saying "10キロほど" sounds OK, but "何キロほど" a little unnatural. (I don't think the grammar changes when 遠く is added)

By the way, I think the description "as much as" applies more to ほど but not as much to まで.