I use a JVM410H through a 4x12 cab in my bedroom and I don't use an attenuator.
There are different qualities of attenuators as well. Attenuators are used to divert and dissipate some or all of the amplifier's excess or unneeded power in order to reduce the volume of sound produced by the speaker.
Depending on how the attenuator functions, you may get the entire pre-amp and power amp tube distortion at lower volumes. However, this usually comes at some amount of tone loss. Sound=air particles vibrating; therefore less volume would have an effect on your EQ.