Why DON'T You Like About Your Eisenman or A.A?

[linsm3]

The Eisenmann is sometimes a bit too loud for me but it really sounds great with acceleration, at this point I have it so I'd better get used to it. If you want a great sound and are willing to spend the money I don't think you'll regret getting it.

[M3 Montreal]

[u2b]www.youtube.com/watch?v=v000BRGTUiU[/u2b]

THis video will give you a better idea of what the AA X-pipe and exhaust sound like on load and throttle.

The video on the previous page is not indicative of the true sound at all in my opinion.

Hmmm video not showing heres a link...

[dcstep]

Originally Posted by frankzlin79

Okay I have a sound pressure meter with me now. With a passenger taking the readings, I found that cruising from 60 mph - 70 mph, the sound levels were hovering around 92-94 dbs. When I was slowly accelerating from 0 mph to around 30 mph, I saw a spike at 99 db..but it stayed close to around 97 dbs. I'll try to post an HD video and maybe come up with a simple chart for you guys.

Ok, I think that I see the problem. I'm using A-weighting and you're using C-weighting. I was confirming my readings and thought to try the C-weighting and did indeed get readings in the 90+ dB range. However, A is the most commonly used weighting because it mimics how we hear and is the standard measure for determining potentially dangerous sound levels. See the excerpt below from Wikipedia:

"The curves were originally defined for use at different average sound levels, but A-weighting, though originally intended only for the measurement of low-level sounds (around 40 phon), is now commonly used for the measurement of environmental noise and industrial noise, as well as when assessing potential hearing damage and other noise health effects at all sound levels; indeed, the use of A-frequency-weighting is now mandated for all these measurements, although it is badly suited for these purposes, being only applicable to low levels so that it tends to devalue the effects of low frequency noise in particular[1].

A-weighting is also used when measuring noise in audio equipment, especially in the U.S.A. In Britain, Europe and many other parts of the world, Broadcasters and Audio Engineers more often use the ITU-R 468 noise weighting, which was developed in the 1960s based on research by the BBC and other organizations. This research showed that our ears respond differently to random noise, and the equal-loudness curves on which the A, B and C weightings were based are really only valid for pure single tones."

[frankzlin79]

Oh, good point. I was in fact using C-weighting. I thought that was what I was suppose to use. My home theater was also calibrated with C-weighting. This puts a new twist on all the other db values we've seen in the past! When people say, they get 95 dbs, for example, I wonder if that is on A or C weighting?

[dcstep]

Originally Posted by frankzlin79

Oh, good point. I was in fact using C-weighting. I thought that was what I was suppose to use. My home theater was also calibrated with C-weighting. This puts a new twist on all the other db values we've seen in the past! When people say, they get 95 dbs, for example, I wonder if that is on A or C weighting?

I was amazed at how large the difference is, almost 20dB. Shows how important it is to be on the same page. We were both "right".

Dave