Computer speakers keep going into "standby"

WannabeGeek_13

Honorable
Jun 8, 2012
1
0
10,510
I'm not sure if this is the best place to post this question, but here goes....

I have a set of Monsoon flat panel speakers + subwoofer that I have used with my computer for several years. They attach to the audio out via a standard 1/8" stereo plug.

When they used to work properly, if they didn't receive an audio signal for a certain amount of time, they'd go into what I call "standby mode." So if I left the computer for 15 minutes, then came back, the first sound that the computer made would have the first quarter-second or so chopped off and a quick "pop" sound from the speakers as they came up out of standby.

Or, if I played a music file that started out really quietly, the signal going to the speakers was not loud enough and they would then come on later when the music got loud enough to trigger the "wake up from standby" threshhold. Once they woke up, if the music got really quiet again, they would continue playing the music the way they were supposed to.

Anyways, they no longer wait before going to sleep, so if I am watching a spoken word video or lecture, they are going to "sleep" and waking up several times in one sentence, in the pauses between the words.

If I play rock music, they sound fine, since the constant audio out keeps them from sleeping.

Does this description make sense? What can I look into to try to fix these? THey are great speakers and even though they're old, I'd love to continue using them.

Thanks for any tips.

Edit - I know it's not a computer hardware or software problem since I just got a new computer and it was doing it on the old computer as well.
 
Solution
So, my wife has had a set of Monsoon MH-500 speakers for more than 13 years. These thin speakers and accompanying sub-woofer deliver sound quality comparable to high-end Bose speakers, but they started popping and crackling over the last year or so. After listing to music and movies on some cheap, unshielded pieces of crap that hum and emit high-pitched whining whenever there is Wi-Fi traffic, I decided fixing the Monsoons was a priority.

There is a "standby" mode that autodetects a signal, and then turns the amp on when one is present. This circuitry was getting flakey and causing the pops and crackles, so after pulling the sub-woofer apart, tracing things around from the indicator LED, and googling some datasheets it amounted to...

stefangriebel

Honorable
Jan 30, 2014
1
0
10,520
So, my wife has had a set of Monsoon MH-500 speakers for more than 13 years. These thin speakers and accompanying sub-woofer deliver sound quality comparable to high-end Bose speakers, but they started popping and crackling over the last year or so. After listing to music and movies on some cheap, unshielded pieces of crap that hum and emit high-pitched whining whenever there is Wi-Fi traffic, I decided fixing the Monsoons was a priority.

There is a "standby" mode that autodetects a signal, and then turns the amp on when one is present. This circuitry was getting flakey and causing the pops and crackles, so after pulling the sub-woofer apart, tracing things around from the indicator LED, and googling some datasheets it amounted to simply shorting the "Stand-by/Mute" pin 11 of the TDA1516CQ to Vp pin 10 (Supply Voltage). This forces Stand-by mode off and now there is no annoying lag when starting music, no annoying shut-off for low-volume music, and most importantly no popping and crackling.

Of course, while trying to show-off the fix to my wife by shorting the pins with a DMM probe, I accidentally touched one of the power rails and blew up an 8-pin DIP IC. This was a TI-555 timer chip, so I went digging in my box of logic circuits and components from college, found a Motorola version (LM555CN) de-soldered the blown one, soldered in the new one, then did a crappy jumper wire solder job and Voila!! So stoked I just had to share.

Link with pictures here:
https://www.facebook.com/stefangriebel/posts/10152218322469587?stream_ref=10
 
Solution