I bought something called a Zebra Box for noise cancellation. I can take a picture and upload online here if that helps with the ongoing noise troubles with the electronic pumps. I recently bought a VacuTech Pulsar and experienced the same concerns even though its rated at 54 decibels. Due to a heavy travel schedule the size and weight was a major factor in avoiding the DP 4000 and the QS-7. I would be interested in hearing a comparison of the DP 4000 and the QS-7 once they finish with the upgrades as they sound very competitive with each other. If anyone is interested in seeing the pictures of this noise cancellation box just let me know. It was only $25 which I felt was well worth it.
Likely worth posting in a different thread but many experienced members have talked about the importance of the accuracy of the tube compared to actual girth size to force length gains but the actual length of the tube.. As a discussion would be interesting as I am very tempted to reduce size from the standard 9 inches in the future and go for 8-8.5 if this would possibly increase length gains more efficiently.
Cheers.