You can use the compressor tool to make the highs and lows a little closer so that the sound is good even from a tiny phone speaker.

您可以使用压缩器工具将高音和低音调的更相近一些，这样即使是小手机扬声器声音也会好听。

youdao

Ditched the landline? Use a hands-free device like a headset or talk on speaker phone (preferably the former when in public).

除了座机，用免提设备像耳机或者用扬声器电话交谈(公开场合前者更好)。

youdao

Don't use a speaker phone unless absolutely necessary.

若非必要，不要使用电话的免提功能。

youdao

To control its volume, I had to adjust it using a button on the small speaker, or use the Sonos app, which I tested on an iPad and Android phone.

WSJ: Raising the Bar for Better TV Sound