| Author | Message | ||
     Andros |
I have the Jardine RT5 can and it sounds really aggressive and tough but bit too loud. I love the sound though buy for city driving its a bit too loud and gets me too much unwanted attention from the cops. I want to build a db killer for it but want to maintain the deepness and rumble of the sound. I'm looking to change the overall volume of the sound not the tone in any way. Have any of you got any ideas on what shape an insert should be? Long, short, perforated, cone in or outwards, little or big hole? The objective is to reduce volume not reducing particularly the bass. | ||
| Jdugger |
Oh, boy. Small volume work is such trial and error, honestly. I can suggest you do some research on Helmholtz resonators to get started, in particular the tube variety. Get out your calculator. http://en.wikipedia.org/wiki/Helmholtz_resonance | ||
| Andros |
Thanx but a little too hairy for me... hheheh =) | ||
| Zac4mac |
Anders - I dropped the sound of my Drummer by rolling up some SS screen and sticking the tube in the muffler. Didn't even need to secure it, as the exit is angled, the tube of screen doesn't move. Z | ||
| Andros |
Great idea. I assume that ss screen is some kind of wire mesh? | ||
| Hellgate |
Andros - I mailed the DB Killer to you today. They said about 10 days. Let me know what you think. Pete | ||
| Bob_thompson |
Andros, check out these two websites (below)for pretty good info on how to reduce sound and NOT loose performance. Well proven and what I have used to a good extent on both cars and my M2 and 1125R. I've had to make them myself to get a small enough size but doable. They do work. Bob http://www.afabcorp.com/AFCO_Dynatech_USbrake/merc hant.mvc?Screen=CTGY&Store_Code=Dynatech&Category_ Code=Mufflers http://www.carchemistry.com/ | ||
| Hellgate |
Here's the Jardine DB Killer/Spark Arrestor. As you can see it isn't large at all. They claim a 6 to 8 db drop but it is more like 1, maybe. It also moves the tone up higher. To install it you simply remove the three cap screws to the cap of the muffler, place the db killer in (cone pointed in) then replace the muffler cap. I think for this to work better the tube inside the wire cone needs to be longer, like about 5 to 6 inches, with a washer welded on the end. I can see how it would help with a thumper but not for this bike. I like the screen idea that Zack used, simple and cheap.  (Message edited by Hellgate on October 23, 2009) | ||
| Andros |
Thank you all i will try some different things out when i get the db killer from you. Will try the ss screen as well to see what gives the best sound. | ||
| Xl1200r |
You're probably not going to quiet the bike down AND keep the strong bass. Anything you do is essentially going to result in passing the exhaust through smaller holes than the straight through design of the Jardine. Think about a speaker - big speaker means lots of bass, small speaker not so much. Same principle applies. To make a muffler that will keep the bass, you either need a larger canister so you put large and spaced out deflectors in place, or create multiple open chambers. | ||
| Zac4mac |
The screen I used was from the "shale shaker" from an offshore drilling rig I worked on 35 years ago. It's about the same mesh as window screen, but the wire is heavier. I'll go pull it apart and take some pix. Z | ||
| Bettybuell |
I don't think the mufflers designed as straight through glasspacks will be quiet on the 1125r. I bought the TM Torque Hammer from Grandstand Design. and it is reasonably quiet, not real quiet and deep. Also the Drummer exhaust works. Both these are mufflers with tubes inside and no packing. I am very happy with the performance and sound of my TM Torque Hammer. I'v had it on track days and the bike is faster than any other twin I have come up on such as RC 51, Super Duke, Aprilia some Ducati's, but I don't think 1198. | ||
| Andros |
How about stuffing a bit of packing in there? Wouldnt it do the same as the screen? | ||
| Bob_thompson |
Andros, one of the things I found in my research for muffler inserts is that you want to fill the whole diameter of the pipe with an insert but any holes you have have to be at least the same square area of the pipe itself. On the cone types I found perforated screen with the size holes and spacing I wanted. I then calculated a given length of the cone to have enough holes to be about 1.5 times the square area of the square area of the pipe or muffler outlet. I ended up with a cone that fit the pipe tightly and was about 6 inches long. It still flows the same amount of air, or exhaust, but cancels out much of the noise. It really does work but takes fabrication and computing the area of the holes. A fair sheet metal worker can make one easily. The one I made was similar to the one below but perforated holes only and longer and narrower. Bob  | ||
| D_adams |
Bob, I'll tell you what, drilling out those damn holes is a freakin pita! Just trying to get them all lined up like that is a real bear of a job.  | ||
| Zac4mac |
I'm pretty sure my Drummer has packing inside the perforated liner. Here's what I did to it -     I decided that while I had it apart, I'd use the dB Meter app I have on my iPhone and check sound levels, with and without. Well, the meter showed virtually no difference at idle(my ears say it IS quieter with) so I left it out for now. Zack |
