I've got an SMS-1 and it has started to only partially work. Bass output is severely reduced to the point of being inaudible even though the driver appears to be somewhat vibrating. Here's the weird part, to get full, normal bass output I have to crank the bass level on the receiver to about +10, then crank the main volume to about -8 until I get a sudden shock of bass that rumbles the whole house. Once I shock the system into operation, I can turn down the volume and bass level to their pre-calibrated settings and everything works fine from then on, until I turn the system off and have to do it all over again.

At first, I blamed the sub for the issue but I've monitored the situation for some time now. When I disconnect the SMS-1 from the system and run the sub directly from the receiver the sub always operates properly, so I don't think I can blame the sub.

What could be wrong with the SMS-1 to cause this situation and what can be done to fix it????

Without more information about your system or settings, my guess is that it sounds as if your sub's "auto on" was not being triggered (if that is how your sub is setup). That's just a guess.

Have you tried the SMS-1 in bypass mode? (I think that's mode 5 if I remember correctly)

Like garcianc2003, I wondered about the sub's auto on mode and a possible conflict with the signal being provided by the SMS-1. An easy test for that would be to set the sub to be always on and leave it that way for a few days. I'd also make sure the SMS-1 isn't in any sort of mode that would cause it to be shut down (such as the 12V trigger mode) or in Night mode (which creates an adjustable "partial muting" of the sub channel).

Thanks for the replies.

To your points, my sub is set to auto on, but even though the light is green and the driver is vibrating it is not being driven enough to be audible. The insanely high level of input signal to "shock" the system into normal operation is far, far more than any auto on function would require. I have set the sub to always on and the symptom still persists.

I also use the 12v trigger on the SMS-1. It seems to turn on and off properly at least as far as the display panel is concerned. I have never used the night mode and have never had to adjust the SMS-1 settings in order to make it work properly. All it takes is increasing the input from the receiver until it works.

I did have one odd experience while running the bass sweeps. For some unexplained reason during the sweeps, I had a sudden dropoff of all bass response from about 40-50Hz and below. Then it started working properly again for an equally unknown reason. I don't know if this is related, but it would appear to me that losing all the lower frequencies would create all the symptoms I describe. Is there a known condition where the SMS-1 will lose the lower part of the signal from time to time???

I can leave the sub and the SMS-1 both in an always on condition, but I assure you that that cannot become a permanent condition. The SMS-1 must be able to be turned on and off with the rest of the system. I'll try these different connections and some different settings to see what works.

There is of course one possibility that we haven't mentioned: a defect. If you bought your SMS-1 from Outlaw, I'm pretty sure that they can help with service or warranty work.

Unfortunately, I purchased the unit used from a member of another forum. I guess that leaves me with 2 issues, confirming the unit is defective and/or finding somewhere to have it serviced. I don't know the warranty status of the unit, but I certainly like using it and would pay to have it repaired if it is defective and out of warranty. Does Outlaw offer this service?

The Velodyne warranty is listed as being non-transferrable (checked the Velo manual). You might still give Outlaw a call and ask them what they can tell you about servicing - even if they're not an authorized service center, they probably know where to find one.