Possible to make a bass shaker amp?

dhp78

Member
2005-04-26 8:01 pm
NY
Hello,

I am new to the DIY world and definitely have much to learn. For now I am just shooting from the hip on some ideas that get into my head. Something I have recently been working on is a racing/flight sim cockpit. Yesterday, I added 2 25W base transducers to the seat for a little touch of teeth shattering vibration.

To drive these I have just my stereo sound output. From there I send the signal thru a car audio crossover that is on a 12V transformer. I use the sub output on the crossover and run it thru another home receiver and then to the transducer. My problem is that I am utilizing a bunch of bulky and relatively expensive equipment to do this.

I would like to know if it is possible to make some sort of low pass filter and single channel 50w amp to do this instead. I have done searches, but not exactly what I am looking for. I would like a predestined circuit that would allow me to get my hands dirty and get me started building some components. If someone could direct me to a well suited schematic it would be much appreciated.

Regards,

dhp
 
well for starters, im pretty much a noob here to, but ive been lurking around and looking to do something similar. what i plan to do is use an old PPI preamp from around '92 to drive a 2-ch 2.5 watt or so headphone amp and a chip amp for a bass shaker on the chair. go to the chip amp section and have a look at brianGT's chip amps. there small, simple, and put out about 50 - 60 clean watts of power. from what it looks like there 4ohm stable, as long as you dont bridge or parallel them, then it gets more complex. i also plan to use a simple active x-over between the preamps rear out and the chip amp so i could adjust frequenceys around 60 - 120 Hz. one of the things im still contemplating is either to use a simple DAC from the computer to the preamp or to just use the analogue outputs of my nforce mobo.

for a crossover... well im still looking, but ill find something suitable... just still looking at amps and power supplys.

i hope this helps and your project goes well. later
 
Some of the chip amps that have circuit boards available here are available in that power. They are also called gainclones, you might search on both.

There is nothing cheaper than a stereo receiver from Goodwill or some such and it would be easy to find one that puts out 25 w /ch for $30 at most. still really bulky though...

I didn't realize you had to filter out the highs- makes sense . What happens if you send higher notes throught the things- do you feel I high frequency tingling?
 

dhp78

Member
2005-04-26 8:01 pm
NY
Thanks for the response guys. I was unaware of the gainclone until it was pointed out. I still do not fully understand it but looks interesting do far. I still have much investigating to do so that I understand what it is capable of.

I thought about the sub amp or the good will amp but I thought it might be fun to try to put something together. I am sure I would mess it up and waste a bunch of cash, but I do that often and usually learn something as a result, so it is somewhat worth it.

I just assumed I will need a low-pass filter. The data sheet that came with the transducers gave a max frequency input so I kept it below that number. Also, I wanted them to energize only when “driving” over gravel, rumble strips, or during a collision, etc. It is not working exactly like that, but is giving a decent effect so far. I assume that if I applied an unfiltered signal they would shake nonstop, and maybe even buzz a bit. I suppose I could find out easy enough.

So far I have the transducers mounted directly to a hard plastic boat seat that I got at wal-mart for $7. I have one mounted in the back and one underneath in a series circuit. I may have to move the on the back because the effect is pretty extreme. It feels like it is shattering vertebrae and gives the feeling of motion sickness. Maybe I will reduce the volume and see how that works.

I hope to build a complete frame to mount all the hardware soon. I also hope the wife will apply some upholstery to the seat for comfort and dampening. If I ever finish I will try to link some pics so you guys can shake your heads and wonder what would possess someone to take the time to make such a contraption.
 
Tragically, we understand you perfectly :D

I am constantly tempted by those Aura shakers for EXACTLY the purpose you are considering. I figured I could attach them to a cool bucket style chair for my son to use for his x- box. What has stopped me is the knowledge that the next thing needed will be one of those packages with a joystick for the right hand and a throttle for the left- one on each chair arm!! Then we would need some speakers and an amp for the regular sound - although it suddenly occurs to me that headphones might actually be cooler.... but non- directioal. So I think you might as well make about 5 of the amps channels so you can at least have 4 channel sound.

And what fun is all that without 3 19" LCD panels across the front? This is getting pricey!

I've got too many projects going at the mmoment , so I'm exercising SOME control- Also he isn't reallly addicted to video games yet, and I wonder why I would ewant to encourage it!!!

Anyway the chip amps are easy to make, and you have no need to get any sort of premium componants. Even the power supply transformer could be anything that works-

The crossover? You can use a electrolytic non- directional cap - something we normally hate, but is cheap, AND an inductor with a core- but that still might get really pricey. The auto crossover is easy. Mybe someone could calc the size of passive components for the INPUT of your amp- that can work fine..

I'll look for some links- but too busy a this moment..