Question regarding a new header

I have recently installed a header on my car. After installing it, there were no apparant leaks. While driving it though and accelerating, I hear kind of like a "whining, bumble bee" kinda noise. That's the best way I can describe it. To me it sounds like a small leak, but in talking to others, they say it's probably normal and it's just the air passing through the header. I plan on removing it and reinstalling it to see if the donut by the cat may not be seated properly. Before I do though, I was wondering if anyone had any feedback, or if they have the same noise in their car after installing a header. Any help would be greatly appreciated. Thanks.

Hey man, i installed a DC Header on my 03 civic ex and I had no problems at all. I recently installed a catback and I hear the same type of noise coming from it. Take it step by step and try to pinpoint exactly where the problem is.

So does that mean it's normal or a leak? I have a CAI and a cat back as well.

its most likely normal. sometimes, aftermarket stuff doesnt bolt up to stock as expected, so somewhere (probably at the cat) its leaking and there is really nothing you can do about it.

it is completely normal......you have more air flowing thru so it sound diff from your stock exhaust manifold....every car that i have put header/headers (i owned a few mustangs ) have sounded like that.....nothing to worry, but if you notice a lot of decrease in power then check it out.......but it sounds like nothing is wrong.