frequency response curve

[Micheallong]

Hello,

i´ve noticed the programm etf or rplusd gives a psychoacoustic response curve which should be more acurate to what the human ear would percive (different intergration times//gate times). Is there an equal help in REW or comes it really close to our perception...

thank you

[Wayne A. Pflughaupt]

This is probably a question for John M. If he doesn't reply, send him a PM.

Regards,
Wayne

[JohnM]

Sorry for the delayed reply, been travelling for the last 20 hours. There isn't an equivalent feature at the moment but it is being looked at.

[Micheallong]

Hey John & Wayne),

thx for your reply.
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.
It would be nice if you could help me

thank you so much

[brucek]

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

So, if the direct signal is being cancelled by the reflected signal (causing a dip), adding gain to the direct signal will also add gain to the reflected signal. There's no winning with dips and adding gain. Positioning would help much more.

brucek

[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

[JohnM]

Above 200Hz or so the gate time that approximates the way our ears work is about 5ms, which is to say that reflections inside 5ms tend to be perceived as part of the initial arrival and so their effect on the response colours our perception of that direct signal, whereas after 5ms the arrivals are perceived as distinct from the initial arrival and correcting for them would overall have a detrimental effect on the perceived balance.

[Micheallong]

ouh....aha..

thx for your answers!!...very interesting.