maniak

I've seen video of the difference between the stock v6 and the gt take off (single) muffler.. But it was still hard to tell the difference in sound (quantity)..

So....

I took some video of before and after installing a single GT take off.. The catch is, the video is of my SPL meter so you can "see" the difference in sound quantity..

I have a .wmv and .mpg...

wmv link is... http://mark.legendz.com/mustang/v6-compare-1.wmv
mpg link is... http://mark.legendz.com/mustang/v6-compare.MPG

For those of you that are bandwidth challenged (like I am when home).. The short answer is that the GT muffler is 2db louder at idle (750 rpms and 1000-1200 rpms).. But at close to 3k rpms (highest you can go when in neutral) it is 11 db higher..

~Mark

Gash05

That's really cool how you did that, how much did that meter cost?

maniak

It an old radio shack analog meter.. I don't remember how much I paid for it.. I got it Years ago when I used to do competition sound systems..

That meter, with a spread sheet and a test disc and I could get frequencies perfectly flat..

~Mark

Gash05

NICE I'll have to pick up one to compare DB's once I get my exhaust set up

Hambone

Nice work! What a great comparison...thanks for sharing it!!

What about frequency differences between the two? I think there is a whole lot more low frequency with the GT muff(s)...do you agree?

Hambone

Oh..another question---isn't dB a log scale? So, 3 dB is double, and the next 6 dB is double that (9 dB)? Hrm, been a while for me, I forget!!

So--doesn't 11 dB (@ 3000 RPM) 'translate' into something like 3 times more sound from the GT muff than stock?

Hrm...or is 10 dB 10x as much sound, and 20 dB takes 100x as much sound.

Or maybe you can help translate from dB into how much "more" sound it is to our ears?

maniak

Yes it is a logarithmic scale...

It takes twice as much power to make a 3db gain, and it takes 10x the power to make a 10db gain.

Yes the frequencies are slightly different.. Which also throws in a monkey wrench...

The Radio Shack analog SPL meter does not read the same SPL for different frequencies.

I have a chart I use which shows me how far off the Radio Shack meter is at certain frequencies. E.g. When I'm testing 30hz I may add 6 DB to the reading, but when I'm testing 150hz I may not have to add anything. But for general, just getting an idea, the SPL meter worked.

What I really need to do a better comparison is an RTA (Real Time Analyzer).. That would show me how may SPL the exhaust had, and at which frequencies, but I don't have access to one of those..

You might be able to find a smaller stereo shop that has an RTA that would test the exhaust for a small fee (if any). They come back with the next exhuast and have them check it again.. I live too far in the boonies to do something like that.

~Mark

Hambone

Hey, thanks for the additional info. Your study is plenty scientific for me Thanks again for measuring the numbers.

I'm really thrilled to be able to tell any stock V6 dude that "my GT takeoffs are 11 dB louder than yours at 3k RPM" hehehehe. Sounds sufficiently geeky to me!

hamidlmt

This was a dandy idea to compare the two! Nice job!

TorchRedV6

Thanks for the innovative comparison. Well timed for me since my GT muffler goes on tomorrow. Got my GT bumpers and rocker panels put on today and tomorrow they are putting on just the single muffler tomorrow until I get paid and go with true duals with an h-pipe!!