Audio Systems: wireless receivers in rack mount, sound reinforcement system, wall warts

Question
QUESTION: I have 3 wireless receivers. 2 are identical Sennheiser Freeport models for my guitars. 1 is a Samson older UHF for my voice. In addition, I have an ART pre-amp that is connected to the Samson for voice. I just put those in a rack mount last nite, Sennheisers underneath the others. I tested everything last nite at home to make sure it worked.
When I got to church this a.m. I didn't have much volume on the guitars. I ended up going direct for the guitars, and using only the samson in the rack box. any ideas?
thx

ANSWER: Did you change the batteries? If you are using a preamp to boost the gain from the voice receiver how do you suggest that the guitar receivers can get the extra gain. Not to say that this is the correct or incorrect method. But you need to measure the gain for each device at the input to your sound reinforcement system. The average voltage should be equal.

---------- FOLLOW-UP ----------

QUESTION: thx much for your reply. I have used these for the last year. just got the rack box. was curious if there is a problem mounting them and the power strip all in the same box. I coiled the power cords up, and plugged the "wall warts" into a power strip. All antennaes are front mounted. I use the ART pre-amp for "coloring" the vocal sound not so much boosting it.

thx

Answer
The rack and antennas will not cause gain problems. If they did create problems it would relate to reception, not volume. I assume that the Sennheisser wireless are diversity. Even if they weren't, gain would not be affected. You would lose or have poor reception and hear FM noise.