[Wayne A. Pflughaupt]

Micheallong wrote:

It would be very nice if you could help me to understand the following thing. I really get this wrong i think.

-For example if there is a delay from a nearby wall causing a reflection that is 6ms later than the direct signal - making a dip at 83hz for about 6db and i will help it with an equalizer a little bit (for example a 4db boost)...
...would it be possible that our ear could notice this boost as an overemphasis on short signals (basedrum) arriving our ear earlier than this reflection at 6ms (or perhaps even later). Or isn´t the ear able to seperate in this short durations because it really needs to avarage for a longer time.

Well, I don't think even "short" signals from a kick drum are as short as 6ms. As to the prospects of equalizing a dip caused by delayed vs. direct signals, time-domain issues such as this are also known as phase issues. Typically there are two causes for dips in response: Nulls, which are wholesale cancellations that cannot be equalized, and phase issues, which can.

Indeed, we typically see people successfully equalize phase issues around the crossover region all the time, so the answer to your question is probably "yes." The reason it will work is that equalizer filtering also introduces phase shift. To further explain, here's a quote from Rane's Exposing Equalizer Mythology tutorial (bold emphasis mine):

The frequency response of most performing rooms looks like a heart attack victim's EKG results. Associated with each change in amplitude is a corresponding change in phase response. Every time the amplitude changes so does the phase shift. In fact, it can be argued that phase shift is the stuff that causes amplitude changes. Amplitude, phase and time are all inextricably mixed by the physics of sound. One does not exist without the others.

An equalizer is a tool. A tool that allows you to correct for a room's anomalies. It must be capable of reproducing the exact opposite response of the one being connected. This requires precise correction at many neighboring points with the associated phase shift to correct for the room's opposing phase shift. It takes phase shift to fix phase shift. Simple as that.

Regards,
Wayne