I have a question about something being heard in the song Ursus Arctos by the sludge/doom metal band Omega Massif

http://www.youtube.com/watch?v=8CKXLNL5YlA

My question is about the beginning; the first two minutes or so, and it's about the background guitars. I'm not too sure how exactly they are getting that effect. It's as if they are merely getting feedback from their amps, but are changing tones with a sort of fading in and out effect. I asked them on their Facebook page how they were getting that effect and they replied "i use distortion, delay, hall, volume pedal for this!". Now keep in mind they are German and the translations may not be all that accurate, but for the most part this makes sense, although I don't exactly know what "hall" is, and in any case I'm still not exactly sure how you would go about doing this type of effect. Can anyone help me out?

My guess is "hall" refers to a reverb effect.

I believe "hall" is a rough mistranslation of reverb/echo.

Even with that in mind though I'm still not really sure how you would go about performing that effect

With a reverb pedal, or post-processing by adding a reverb effect in production.

It sounds to me like he's playing the chord with the volume pedal cutting off the sound, and then bringing the actual sound level up fairly quickly. By using delay and reverb, it gives it that big, massive sound, which also helps to cover up the usage of the volume pedal. Might not be right, but that's how I'd try and replicate it.

I'm going to be practicing with my band today and I'll try that out, we'll see how it goes

I was able to get something very similar to it. Thanks everyone for your advice!