Loud Audio thump on boot up

[Amp Doc]

Whenever I start the PC, if the monitor amp is on, there is a very loud thump when the drivers load to my mbox mini. It does the same thing when powering down the PC. This happens about 1 sec. before the green led comes on during bootup. Is there a firmware update for this? Has someone come up with a mute circuit? if not, I will design one and share it with anyone that wants it. Thanks for reading.

PCTOOLS LE 8.04
OS: WIN 7 HOME PREM. SP1 32 BIT
RAM: 3GB
CPU: INTEL DUAL CPU 2.2GHZ
ONE HD
MBOX MINI VER 1 ON USB
NO OTHER USB DEVICES EXCEPT A PRINTER.

[sunburst79]

Originally Posted by Amp Doc

Whenever I start the PC, if the monitor amp is on, there is a very loud thump when the drivers load to my mbox mini. It does the same thing when powering down the PC. This happens about 1 sec. before the green led comes on during bootup. Is there a firmware update for this? Has someone come up with a mute circuit? if not, I will design one and share it with anyone that wants it. Thanks for reading.

PCTOOLS LE 8.04
OS: WIN 7 HOME PREM. SP1 32 BIT
RAM: 3GB
CPU: INTEL DUAL CPU 2.2GHZ
ONE HD
MBOX MINI VER 1 ON USB
NO OTHER USB DEVICES EXCEPT A PRINTER.

Hello Doc. Welcome to the forum.

What you describe is a fairly common problem. In general and not limited to the MBox or any particular brand of interface. Depending on your system some people recommend turning the monitors on last to avoid this. And turning them on first. Other monitors like mine are supposed to stay on and plugged into the wall 24/7 to avoid thumping when turned on and to ensure they have nothing restricting there power draw. Stuff like this kinda needs to be looked at on a case by case basis. I can't say as I heard a lot of complaints about this. There is no firmware update im aware of to take care of any turn on transients.

There was a thread in the ElevenRack section about turn on thump not to long ago. I bet those guys would be interested in something like that that was also capable of blocking phantom power from frying the XLR outs.

[albee1952]

One solution is to put your speakers on their own power strip/switch so you can power them up AFTER the system boots, and power them off BEFORE.

I recommend going a bit father though. I would buy a good APC UPS unit($169-$199 at Best Buy) to feed your computer and anything else on your setup, EXCEPT the speakers. I would give them their own power strip plugged into the wall. If you have a power failure or glitch, its not so important that the speakers stay on(but it can and will save data from corruption!!). I found some nice rack-mounted power strips with 10-12 outlets on the back, with a handy power switch on the front

[Craig F]

the other option would be some form of monitor box that has Volume Control and a Mute button at least
maybe source and speaker switching also for growth

[Amp Doc]

Thanks guys for all the suggestions. I have a separate power switch for my audio amp. What I was talking about was an automatic mute circuit for the M-box so in case I forget to power down the speakers or the PC goes to sleep, I wouldn't hear the sound of a small bomb from the sound system. I will come up with something and post it here.

[sunburst79]

Originally Posted by Amp Doc

Thanks guys for all the suggestions. I have a separate power switch for my audio amp. What I was talking about was an automatic mute circuit for the M-box so in case I forget to power down the speakers or the PC goes to sleep, I wouldn't hear the sound of a small bomb from the sound system. I will come up with something and post it here.

Looking forward to that.