If I use the second sub out connection on my avr, do I need to do anything as far as delay goes?
This will depend on several factors:
1. How far away your subwoofer is from your seating,
2. What amp you use to drive the Buttkicker,
3. How your Buttkicker is connected to the amp,
3. What amp your subwoofer uses.
All of these factors can add some latency, (delay), to the signal. If your sub is nearfield, (very close to the seating), there will be a little "propagation delay," (the time it takes the soundwaves to propagate across the space to reach your ears. However, if the sub is across the room from you, there'll be approximately 1 ms of propagation delay for every foot of distance the sub is away from you. If it's 12' away, there'll be about 12 ms of delay from the time the subproduces the sound wave until you hear it. If the Buttkicker is not delayed by the same amount, you'll feel the shaking before you hear the bass. 12 ms of mistiming between the shakers and the bass sound would definitely be noticeable. However, if you're using the Wireless kit it will delay the Buttkicker by 9 ms. If the amp driving the Buttkicker has a little latency in it, it could delay the signal another 3 ms, and then they would be perfectly timed. However, if the subwoofer amp has a little latency in it, it will delay the subwoofer a little bit, and you'll be slightly mis-timed again.
Also, will I need to re-run audyssey after connecting the buttkicers to the avr?
If you just have one subwoofer, then Audyssey doesn't apply Room Correction to the 2nd subwoofer output, so you don't need to re-run Audyssey. You can just plug your shaker into Sub2 and you're good to go. However, if you have 2 or more subs, and you previously were using both subwoofer outputs to run the subs, then Audyssey RC would be applied to both outputs. Transducers don't benefit from RC, so you don't want it applied to the transducers. Therefore, you would hook all subwoofers up to the Sub1 output, then re-run Audyssey with the transducers off, and then turn the transducers on again after running Audyssey.
You can also use the Sub2 Distance control in your receiver to adjust the relative delays for the transducers. Just put on some bass-heavy music and play around with the Sub2 Distance setting. You'll be able to tell when the settings are getting further off, and when they're getting better. When they''re "just right" the bass will hit at the exact same time as the shaking, and it will feel like the shaking is a natural part of the sound.
Craig