phase cancellation ?

[JCsAudio]

Come on guys! Don’t turn this into another caraudioforum where you get attacked if you don’t word the question right or ask the right question. This place will die out if that happens.

Queef, I’ve experience what you call SBIR, also referred to many times as a null on DIYMA that in my case causes a big dip in the response around 500 Hz that no amount of EQ can fix. Where did you come up with that graph?

[Jdunk54nl]

Come on guys! Don’t turn this into another caraudioforum where you get attacked if you don’t word the question right or ask the right question. This place will die out if that happens.

Queef, I’ve experience what you call SBIR, also referred to many times as a null on DIYMA that in my case causes a big dip in the response around 500 Hz that no amount of EQ can fix. Where did you come up with that graph?

But there wasn't a question asked, that was the issue...Just some statements posted with just enough good information to get someone to believe it, but also a lot of mis-information. That is why I asked in post #2 what question he had on phase so we could answer it.

Also if you look at post #3, Justin called this happening. We are having a "roaring" debate about nothing

[JCsAudio]

Jdunk54nl, I hear you man and hopefully what Justin said doesn’t happen and I agree it should be phrased more as a question. Just trying to steer this away from going negative. This place has become more active since the DIYMA debacle with Nick so I don’t want to see it go in the wrong direction.

[Queef]

My Bad ! I apologize for not explaining , spelling out exactly why I was addressing this issue

[Jdunk54nl]

So. Let's try this again. What questions do you have about phase?

Also, carpeting, padding, dash mats in vehicles isn't going to do a whole lot for subwoofer frequencies, which seems to be your focus. Mainly due to the amount needed to make a difference would make the vehicle unsafe for road travel.

Then your example of path length differences, look at those distances, 11 feet and 18 feet. How big is your car cabin? Go out to your vehicle and measure and figure out the path the sub frequencies would have to travel to get to 11 feet and 18 feet. I highly doubt you will get an 11ft direct path length...

A lot of people will get this in the ~400hz area if they have a center console and door mounted mids. Center consoles are about 18-24" away from the door. An 18" path length difference would be a 400hz cancellation. A 24" path length difference would be about a 280hz cancellation.

Also, sound follows the inverse square law, so every time we double the distance, the sound gets cut by about 6db. My wife's SUV has the sub at 4'8" away from the listening position. It is about 2' from the back hatch. So to go to the back hatch and back, the sound gets cut by ~6db. This 4' path length difference gives a cancellation frequency of 140hz. So, at 140hz, which is already cut by 24db since her crossover is at ~70hz, has the reflected sound cut by an additional 6db.

[Jdunk54nl]

Come on guys! Don’t turn this into another caraudioforum where you get attacked if you don’t word the question right or ask the right question. This place will die out if that happens.

Queef, I’ve experience what you call SBIR, also referred to many times as a null on DIYMA that in my case causes a big dip in the response around 500 Hz that no amount of EQ can fix. Where did you come up with that graph?

That graph is here
http://www.acousticfrontiers.com/wha...-interference/

[Justin Zazzi]

My Bad ! I apologize for not explaining , spelling out exactly why I was addressing this issue

So, what is your question? What do you want to learn? [intelligent question] <<<like this

[Queef]

I was not asking a question. I cut and pasted what apparently to some is BS. I was attempting to post a little insight into a problem another member seemed to think might have been "cancellation".

If I do require help, I will pm you on it.
Thank you, Justin.
P. S. Please feel free to search the internet and explain to the people I have used "what you know" ?

[Queef]

Justin Zazzi

Wave ShepherdPost Thanks / Like LocationTempe, AZPosts31Join DateAug 2018Feedback Score

Re: phase cancellation ?

This looks like a copy/paste of different conversations with just enough incorrect claims to spawn a few pages of roaring debate about nothing.

[QUOTE=Queef;47561]phase coherency is necessary for maximum enjoyment . [/QUOTE]< I posted this, my thoughts

It destroys impact and obliterates low end. It makes musical tracks sound thin and lifeless . [/QUOTE]< not me = truth or fiction ?

Phase cancellation is a an audio phenomenon where the waves of multiple tracks work against each other to eliminate certain frequencies. The resultant sound is often flat or dull.[/QUOTE]<not me = truth or fiction ?


Phase cancellation occurs when two signals of the same frequency are out of phase with each other resulting in a net reduction in the overall level of the combined signal. If two identical signals are 100% or 180 degrees out of phase they will completely cancel one another if combined.

not me = truth or fiction ?

Please call out what you saw as incorrect ?

[Queef]

If either of you would care to add more to this thread or start a new one on ways you sort out phase (pink noise, white noise, reversing polarity, etc.., ) . I for one , am looking forward to your responses, Justin and Justin?