SOS Forum Post
Technical Editor Hugh Robjohns replies: The HR624 is not ported in the conventional sense, but it does employ a 'passive radiator' which is mounted on the rear panel behind the amplifier chassis. Essentially, this is a port with a diaphragm stretched across it. Consequently, it is not a good idea to place the speaker hard against a rear wall, although, as the passive radiator is tucked in behind the amplifier chassis, it is impossible to place it hard against a wall anyway.
Personally, I'd recommend wall-mounting your monitors using good sturdy hardware that holds the speaker about 4 to 6 inches away from the wall. That way, the speaker vibrations are completely isolated from everything else and the speaker is held firmly in position. Adjust the wall brackets or the speaker mounting so that the tweeters are aimed at the listening position.
Many wall brackets are designed to be fixed to the speaker with bolts through its back panel. Some speakers intended for wall mounting in this way come with bolt holes already in place (the PMC DB1 and Genelec 1029, for example). However, if you plan to do the mounting yourself, take great care — the crossover of passive speakers is often mounted internally on the back panel behind the terminal plate, so it might be safer to bolt onto the base of the speaker instead. You can easily check by removing the connector panel and having a peek inside the back of the speaker.
If wall-mounting is impractical, then floor stands are better than table stands, again because they're better at controlling vibrations. If you have to go down the table-mounting route, some form of high-mass damping is usually a good idea. Try either placing the monitors on high-density foam isolators, such as the Auralex Mo Pads, or putting some Spectra Dynamics Deflex anti-vibration sheeting on the table. Place a small concrete paving stone or heavy quarry tile on top of the foam, and Blu-tak the speaker on top of that. The extra mass of the slab will help control and damp vibration, and the foam will help prevent low-frequency vibrations from passing into the table structure.