Multiple mics, multiple transducers, a digital signal priocessor and lots of critically placed damping material on the chassis to minimize NVH plus some alterations to the sheetmetal structure to enhance rigidity and minimized resonance. Quite a few alterations really. And nothing plumbed directly into the exhaust, the concerns were noise radiating from the exterior of the pipe.

Also....

I use "quite steel" in some of my designs/alterations. Are you familiar with quiet steel?

No, never heard of it.

Quiet steel consists of two sheets of high grade maleable carbon steel with a sheet of polymer laminate "laminated in between".

The result is virtually resonance free steel. Somewhat sound absorbing even.

I have samples here that are credit card sized. The steel sample when thrown on the table sounds like a plastic credit card. It's amazing.

Ford started using the material in valve covers to reduce emission of valvetrain noise, and they've added it to some parts of their trucks and cars now. The newest F150/F250 is amazingly quiet!

You must be joking, haha - excellent!

I got the perfect little amp for that and it's stereo the heatsink might be a little big though it's good for about 15 rms a channel.

Jeff

Whoa! A whopping 15w rms/ch would blow my tiny speaker. :smile:

Oh no you just need more speakers..........and stronger springs.:yes:

Jeff

Thats so cool! but really you have too much time on your hands. Reminds of back in 1986 when I had 2 15" pyle pros and a kenwood 1020 bridged in the back of my 1976 toyota corolla station wagon. Stereo was worth more than the car. But It was the loudest in town. Now I cant stand those kids with the loud systems now now I guess I am getting old.

Wow a 1020 that was SOTA back then high steppin! I remember when my mom bought a 84' Caprice Estate Wagon it had a Yahama YCT800, and a set of proton 3 1/2's with a Proton 222 and in the rear were a set of A/D/S 300I plates driven by a Power Plate 120.

Jeff

What funny you dont see many amps now that had as low of a harmonic distortion as that amp did. It was anextremly clean amp. Not much power though. I think back then it was over $1000. I picked it up for ~$600.

Pretty cool Brian, I like it.

It's been a while since I was really into car audio but I was there when the stuff first came out and got to watch the progression until the DB Drag stuff started then I was pretty much out. Everything seems optomized to run at 2 ohms and in some cases even lower so I think that had a lot to do with it, that and the poor quality of the designs. I remember when you opened up an amp it was full of componets then a lot of cheap manufacturers would use IC amps like in Brians design to drive their output stage directly and the specs on those are not the greatest the quality suffered as well. The only one I knew that had anything close to a quality amp was Matts they used the LM10 and 12 to drive their output stage and they were pretty good. About a year before they came out I was looking through the Digi Key catalog (when it looked like a magazine instead of a phone book) and ran across that chip and was like that would be great to run straight to the output stage. Well that IC was about $75 and I didn't have the money to get one (If I knew about samples back then :party:) I would have taken that and the TIP 35/36 and made an amp while I was still in highschool. I ended up making an amp when I went to tech school, but that one used 2 2N3055's for the output stage.

Ahh memories.

Jeff

waterproof-ed?

Now that is serious extra time but the thought did cross my mind for a rc to ride withe music but it was funny what if it played music to actually do it is awesome great ingenuity Only on RCM you find stuff like this to see it created. Next I would like to see an amphibian RC so who is going to make it? Brian:whistle:

Wow, this thread somehow got brought back from the dead!

j57ltr: Those "amps on a chip" have their advantages and disadvantages. The good thing about them is that 90% of the circuit is integrated, so it takes less space, can have better noise rejection, and is simpler. The bad thing about them is that the heavy current stage is also on there, is generally pretty weak, and you might run into thermal issues since it's so compact. However, you could use the chip to replace the differential input, voltage amplification, and pre-output stages, and use outboard transistors for the final stage.

edep345: No, not waterproofed. Although, it wouldn't be all that difficult to do. A little silicone around the various openings of the amp, and a weatherproof speaker would be all that's needed.

swiftneed: You mean like a boat with wheels?