Pulsing LED's to music?

[Two-Six]

I am building a couple of boxes to hold sub-woofers in and I have a few stick-on strips of 12V LED's.  I am considering putting the LED into the sub boxes (with a little window) to at least give out a nice warm glow (they are orange). I could go with just a simple on/off switch, switching 12 volts but it would be nice if they pulsed to the bass.

So, I wonder firstly what would happen if I connected them onto the speaker outputs from the amp, would that do anything or would it break them?  It would be AC and perhaps might peak at 15-20 volts....not sure about that...

Failing that as an idea can anybody think of any way of making them pulse or flash?  Is there any cheap and simple off-the-peg things that could be employed?
 
I might possibly be able to make a circuit using some super simple bits but electronics is not an area I am that good at.

Perhaps a normal bulb or two might be more the thing...

Actually as a side, I got the speakers from an early 90's sub woofer box and it had two blue neon tubes in it that still work when given 12 volts. 

I accidentally connected these to the speaker outputs from the amp and they flashed to the beat (a bit).  They might even have some electronic bits in them to make them flash/pulse..Not sure about that either...

[shawdreamer]

for simple straight forward pulsing you can use any of these variants....
https://www.ebay.co.uk/itm/3-Key-USB-12V-24V-RGB-LED-Cable-Controller-Dimmer-For-Strip-Light-SMD-Lights/272899646531?hash=item3f8a162443%3Ag%3A7Q0AAOSwyXNZ7vl8&LH_BIN=1
theres nothing to complicated about them, just 12v in one end and strip connected to the other, then just cycle press the buttons till you get the effect your after.....job done for pulse or strobe effect.

If you want something a bit more customizable then just use RGB strips and one of the remote versions that allow you to tailor the exact colour you want and offer a few pre-programmed cycle effects aswell as strobing and pulsing obviously...
https://www.ebay.co.uk/itm/24-44-Key-Remote-Controller-USB-Strip-Smart-Mini-RGB-12V-Receiver-LED-Light-UK/174075405883?hash=item2887b3e63b%3Am%3AmttXr2c6zUsj2QCgjklSSwA&LH_BIN=1

there is also a sound responsive version of the upper controller....
https://www.ebay.co.uk/itm/Sound-Sensor-Music-RGB-Controller-LED-Strip-String-Light-20Key-24Key-44Key/153594127323?hash=item23c2ec63db%3Am%3Am4UbV65kJoLBNw4heRuET-w&LH_BIN=1
which will give you the bass pulsing effect you mentioned aswell as the other options the above one gives.

finally theres the bluetooth/wifi versions which I often use which allow you to control the lights via BT & Wifi obviously but in addition to controlling the lights If you controlling source is also producing the sound (eg android car stereo, smartphone etc etc) it can also be set to respond directly to the music/sound being played by that device...
https://www.ebay.co.uk/itm/Mini-Bluetooth-Wifi-LED-Controller-RemoteFor-5050-3528-RGB-RGBW-LEDStrip-U-pp/233364135725?hash=item3655961f2d%3Ag%3AOHoAAOSwUalb2Xhs&LH_BIN=1

[Two-Six]

Thanks for the info I will have a look at these gadgets, they sound pretty much like what I am after. 

I have nearly build the boxes but actually they are in prototype stage the first one is a bit crap, the 2nd one is better and I could do with slowing down a bit with them.

However I really can't wait until they are finished, its gonna sound awesome.  My Disco-van.

Anyway....I might build some perspex windows in them and I might test out a ported and sealed variant.

I think I am going to need a solar upgrade too to power it all for more than 5 minutes.