В моем аудио-плеере нет расстояния между обложками:

<body>
    <div class="container">
      <div class="row">
        <div class="col-md-3">
          <img src="/img/<%= musician.thumbnail || 'avatar.jpg' %>" alt="<%= musician.name %>" width="200" height="200">
        </div>
        <div class="col-md-8">
          <h1><%= musician.name %></h1>
          <p><strong>Role:</strong> <%= musician.role %></p>
          <p><strong>Genre:</strong> <%= musician.genre %></p>
          <% if (musician.role === 'Artist' && musician.instrument) { %>
            <p><strong>Instrument:</strong> <%= musician.instrument %></p>
          <% } %>
          <p><strong>Location:</strong> <%= musician.city %></p>
          <p><strong>Bio:</strong> <%= musician.bio %></p>
		  <!-- audio player -->
		  <div class="audio-player">
    <div class="row">
      <% tracks.forEach((track, index) => { %>
      <div class="col-md-3">
        <div class="track">
          <img src="/img/<%= track.image_filename || 'default-track-image.jpg' %>" alt="<%= track.title %>" width="200" height="200">
          <div class="info">
            <h4><%= track.title %></h4>
            <p><%= track.album_title || "No Album" %></p>
            <div class="progress-bar">
              <div class="progress-bar-fill" style="width: 0;"></div>
            </div>
            <audio id="audio-<%= index %>" src="/tracks/<%= track.filename %>"></audio>
            <button class="play-button" data-audio-id="audio-<%= index %>">
              <i class="fa fa-play"></i>
            </button>
          </div>
        </div>
      </div>
      <% }); %>
    </div>
  </div>

/* audio player */
.audio-player {
  display: flex;
  flex-wrap: wrap;
  /* justify-content: space-between; */
  align-items: center;
  width: 100%;
  padding: 0 10px;
  box-sizing: border-box;
  gap: 30px;
  
}

.audio-player .track {
  position: relative;
  margin: 10px 5px;
  width: 150px;
  text-align: center;
}

.audio-player .info {
  margin-top: 10px;
}

.audio-player .image-container {
  position: relative;
  overflow: hidden;
  width: 150px;
  height: 150px;
}

.audio-player img {
  display: block;
  margin: 0 auto;
  width: 200px;
  height: 200px;
  object-fit: cover; /* Добавлено свойство object-fit */
  transition: transform 0.3s ease-in-out;
}

.audio-player .overlay {
  position: absolute;
  top: 0;
  left: 0;
  width: 100%;
  height: 100%;
  background-color: rgba(0, 0, 0, 0.5);
  opacity: 0;
  transition: opacity 0.3s ease-in-out;
}

.audio-player .play-button {
  position: absolute;
  top: 50%;
  left: 50%;
  transform: translate(-50%, -50%);
  background-color: transparent;
  border: none;
  cursor: pointer;
  outline: none;
  transition: transform 0.3s ease-in-out;
}

.audio-player .play-button i {
  color: #fff;
  font-size: 24px;
}

.audio-player .progress-bar {
  position: relative;
  width: 100%;
  height: 2px;
  background-color: #ccc;
}

.audio-player .progress-bar-fill {
  position: absolute;
  top: 0;
  left: 0;
  height: 100%;
  background-color: #f50;
  transition: width 0.1s ease-in-out;
}

.audio-player li:hover img {
  transform: scale(1.1);
}

.audio-player .track:hover .overlay {
  opacity: 1;
}

.audio-player .track:hover .play-button {
  transform: translate(-50%, -50%) scale(1.2);
}

.audio-player .track:hover .progress-bar-fill {
  transition: width 0.5s ease-in-out;
}

@media (max-width: 768px) {
  .audio-player .track {
    margin: 10px 0;
    width: 100%;
  }
  
  .audio-player .image-container {
    width: 100%;
    height: auto;
  }
  
  .audio-player img {
    max-width: 100%;
    height: auto;
    transition: none;
  }
  
  .audio-player .overlay {
    background-color: rgba(0, 0, 0, 0.7);
  }
  
  .audio-player .play-button {
    transform: translate(-50%, -50%) scale(1.5);
  }
}

gap был задан, это не помогает. внимательно изучи CSS