| 01 | Hard Frequency (Vocal Radio Edit) | 3:39 |
| 02 | Hard Frequency (Vocal Club Mix) | 6:37 |
| 03 | Frequency (Original Club Mix) | 6:37 |
| 04 | Frequency (Megahertz Club Mix) | 5:10 |
| Category | Artist | Title (Format) | Label | Category | Country | Year |
|---|---|---|---|---|---|---|
| ARP 21114 | DB Boulevard | Hard Frequency (CD, Maxi) | Airplane! Records | ARP 21114 | Italy | 2003 |
| ARP 21114 | DB Boulevard | Hard Frequency (12", Promo, W/Lbl) | Airplane! Records | ARP 21114 | Italy | 2003 |
| 5050466-8203-2-7 | DB Boulevard | Hard Frequency (CD, Maxi) | WEA | 5050466-8203-2-7 | Italy | 2003 |
| ARP 21114 | DB Boulevard | Hard Frequency (12") | Airplane! Records | ARP 21114 | Italy | 2003 |
| ARP 21117 | DB Boulevard | Hard Frequency (12") | Airplane! Records | ARP 21117 | Italy | 2003 |