Solved! to add bass guitar amp subwoofer, what splitter

[bridgestone-tired]

Current Set Up: Self powered 4" monitors (two bookshelf speakers)
audio out from TV goes straight to monitors

Desired addition:
[bookshelf speakers] + [bass guitar amp subwoofer! yea!!]
tired of those little speaker sounds I want the real deal!
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I want to put a splitter inline on my audio out from the TV and then send a mono signal to the bass guitar amp. To use it as a subwoofer.

I need something that combines the stereo into mono then I can convert to 1/4' guitar plug for the amp.

I had one with an old computer that had a small box in line between the computer and the desktop speakers that had an extra out labeled subwoofer.
What do i have to search to find something like this. I'm surprised its not more standard or I guess I'm just having troubles as usual.

Please help!
Bradley

 

[americanaudiophile]

This may help
http://techtalk.parts-express.com/forum/tech-talk-forum/60443-stereo-to-mono-summing-circuit
Before worrying about getting both channels into the mono bass guitar amp I would try it by splitting one channel of the TV output.
You won't get the same effect as a real subwoofer using a guitar amp/speaker. It's a completely different animal. No crossover so the amp/speaker will be reproducing the full range not just the bass. Different kind of speaker and cabinet too. The input you need for the TV isn't the same as the one you need for a bass. Levels and impedances are completely different.

 

[bridgestone-tired]

i didn't know sub woofers were so different. I've only used large cabinet speakers before. I was hoping I would be able to get a good sound just by equalizing the signal with the knobs on the amp.but thinking about it now im sure that subwoofers are a lot more tuned . i might do better just finding one thats made to supplement an existing system

 

[americanaudiophile]

I agree.
Since your monitors have 4" woofers you don't need to go larger than an 8" or 10" subwoofer to keep up with the upper part of the bass that they still reproduce.
If you can find a sub that has a line level high pass crossover built in that will reduce the range of bass that the bookshelf speakers have to play. That will allow them to play louder and cleaner.
Don't worry about the power rating of the sub. Many manufacturers aren't accurate at this rating and it doesn't tell you how loud the sub will play anyway.