From a psychological and physiological standpoint, using free or ripped versions of the Hemi-Sync tapes carries the same inherent risks and benefits as using the official versions. The audio cannot "brainwash" a listener, but the deep meditative states it induces can be intense.
If you cannot afford the official tapes, use the legitimate free trials (the Monroe Institute YouTube channel has several pure signal samples). Use the Expand app's free tier. gateway hemisync tapes cracked