Gson returning characters with invalid accent

I'm getting information using Gson in a PHP file. When this information is received, words containing accents are not encoded.

I already read: Android JSON CharSet UTF-8 problems

Converting String to Android JSONObject loses utf -8

An Error in Converting android JSON to UTF-8

But none of these worked for me, as it does not follow the example of my app.

musicas.php

[{"nome_titulo":"Música 1","nome_subtitulo":"Título","indicador_tempo":"2:00"},{"nome_titulo":"Música 2","nome_subtitulo":"Título","indicador_tempo":"4:10"},{"nome_titulo":"Trémbo","nome_subtitulo":"Caractere Inválido™","indicador_tempo":"4:10"}]

ActivityPrivate.java

//Se alguém souber também consertar o AsyncTask irei ficar grato, pois ele não está carregando o ProgressDialog até a lista ser exibida, mas isso é de menos, estou me importando mais com os caracteres
new Musics().execute();

    private class Musics extends AsyncTask<Void, Void, Void> {
        @Override
        protected void onPreExecute() {
            super.onPreExecute();
            // Showing progress dialog
            pDialog = new ProgressDialog(Menu.this);
            pDialog.setMessage("Please wait...");
            pDialog.setCancelable(false);
            pDialog.show();

        }

        @Override
        protected Void doInBackground(Void... arg0) {
            final RequestQueue queue = Volley.newRequestQueue(Menu.this);
            final String url = "http://urlsiteaqui.com.br/musicas.php";
            final StringRequest stringRequest = new StringRequest(Request.Method.GET, url, new Response.Listener<String>() {
                @Override
                public void onResponse(String response) {
                    Log.d(TAG, "Response " + response);
                    GsonBuilder builder = new GsonBuilder();
                    Gson mGson = builder.create();
                    List<ItemObject> posts = new ArrayList<ItemObject>();
                    posts = Arrays.asList(mGson.fromJson(response, ItemObject[].class));
                    adapter = new RecyclerAdapter(Menu.this, posts);
                    recyclerView.setAdapter(adapter);

                }
            }, new Response.ErrorListener() {
                @Override
                public void onErrorResponse(VolleyError error) {
                    Toast.makeText(Menu.this, "Ops, error", Toast.LENGTH_SHORT).show();
                    Log.d(TAG, "Error " + error.getMessage());
                }

            });

            queue.add(stringRequest);
            return null;
        }

        @Override
        protected void onPostExecute(Void result) {
            super.onPostExecute(result);
            // Dismiss the progress dialog
            if (pDialog.isShowing())
                pDialog.dismiss();

        }

    }
}

RecyclerAdapter.java

import android.content.Context;
import android.support.v7.widget.RecyclerView;
import android.view.LayoutInflater;
import android.view.View;
import android.view.ViewGroup;

import java.util.List;

/**
 * Created by Drama on 05/08/2016.
 */
public class RecyclerAdapter extends RecyclerView.Adapter<RecyclerHolders> {
    private List<ItemObject> itemList;
    private Context context;
    public RecyclerAdapter(Context context, List<ItemObject> itemList) {
        this.itemList = itemList;
        this.context = context;
    }

    @Override
    public RecyclerHolders onCreateViewHolder(ViewGroup parent, int viewType) {
        View layoutView = LayoutInflater.from(parent.getContext()).inflate(R.layout.listar_item, null);
        RecyclerHolders rcv = new RecyclerHolders(layoutView);
        return rcv;
    }

    @Override
    public void  onBindViewHolder(RecyclerHolders holders, int position) {
        holders.title.setText(itemList.get(position).getTitle());
        holders.subtitle.setText(itemList.get(position).getSubtitle());
    }

    @Override
    public int getItemCount() {
        return this.itemList.size();
    }
}

RecyclerHolders.java

import android.content.Intent;
import android.support.v7.widget.RecyclerView;
import android.view.View;
import android.widget.TextView;

import java.util.List;

/**
 * Created by Drama on 05/08/2016.
 */
public class RecyclerHolders extends RecyclerView.ViewHolder implements View.OnClickListener {
    public TextView title;
    public TextView subtitle;

    public RecyclerHolders(View itemView) {
        super(itemView);
        itemView.setOnClickListener(this);
        title = (TextView)itemView.findViewById(R.id.titulo);
        subtitle = (TextView)itemView.findViewById(R.id.subtitulo);

    }

    @Override
    public void onClick(View view) {

    //passando dados recebidos para uma nova atividade
        String value = title.getText().toString();
        String valueSub = subtitle.getText().toString();

        Intent intent = new Intent(view.getContext(), Player.class);
        intent.putExtra("title_music", value);
        intent.putExtra("subtitle_music", valueSub);
        view.getContext().startActivity(intent);
    }
}

ItemObject.java

import com.google.gson.annotations.SerializedName;

/**
 * Created by Drama on 06/08/2016.
 */
public class ItemObject {
    @SerializedName("nome_titulo")
    private String title;
    @SerializedName("nome_subtitulo")
    private String subtitulo;
    public ItemObject(String title, String subtitulo, String tempo) {
        this.title = title;
        this.subtitulo = subtitulo;
    }

    public String getTitle() {
        return title;
    }

    public String getSubtitle() {
        return subtitulo;
    }
}

Thank you very much, thank you in advance!