Roms SQ Diary

[kzaki]

Nopes zaki bhai, time is constant and the 180 degree shift (Inverted polarity) only shifts the amplitude of wave at certain frequency.

sir actually reversing the polarity does work in bringing much of the frequencies back to phase but it doesn't do the same thing as a proper T/A device.
By moving inward first then outward (instead of outward as soon as it receives a signal), we can assume that it is 180? out of phase, which translates to about 1.0ms but again this is a simplified version and swapping polarities really doesn't work exactly like T/A (where you add some delay to the signal) .

[roms]

sir actually reversing the polarity does work in bringing much of the frequencies back to phase but it doesn't do the same thing as a proper T/A device.
By moving inward first then outward (instead of outward as soon as it receives a signal), we can assume that it is 180? out of phase, which translates to about 1.0ms but again this is a simplified version and swapping polarities really doesn't work exactly like T/A (where you add some delay to the signal) .

I am loving it Zaki Bhai,

The 180 degree you are referring to is known as compression or rarefaction. One driver at zero degree and one driver at 180 degree will do the phase offset and merely sets the amplitude.

Inverse of the wave will be created If you were to shift it in time and that would shift all parts of the wave in same amount and for whole wave.
As you said, time delay the wave. A phase shift will not do that - it will merely alter the amplitude at a given time. Apply a 180 degree phase shift and you have treated the amplitude such that at a given time, t, it is now the inverse of what it is on the original waveform. ie whatever it was on the original it is now the same value but with the opposite sign.

[roms]

Rear Fill Speakers

How many of us use Rear Fill Speakers ? few
If you dont have a processor and stage is pulled backwards when you fire up your refills then i have a solution for you guys.

Ever heard L -R Signal ?

With a processor it is very easy derive L-R using a set of a modern head unit's amplified outputs. Only. You need bridged outputs! You see, the amplifier outputs of a head unit do not reference ground. They are bridged internally to provide more power to your speakers. Instead of a positive feed and a ground per channel, you get a positive feed and the opposite feed which is 180 degrees out of phase (or a bridged channel). Tie your rear speakers in series then wire them across left channel + and right channel +.
That's all you need to get L-R.

The same thing can be done if you have a spare 4 channel amp you can hook up to the rears only. The amp must be bridgeable without needing to use a switch to bridge. If you have an amp that you need to flip a switch to bridge then you only need 2 channels. See my comments in an earlier post in this thread regarding the 2 channel amplifier solution. Basically, the same principle applies as with the head unit.

[roms]

You combine L in phase with R out of phase, So you are adding (L)+(-R)... Mmm Kay? Now anything that is L+R, or panned dead center will be canceled out because in the summing it will net 0. If something is panned, say 1 dB in one direction then the result of the summing will cause it to have a 1 dB level over the receiving device. Anything panned hard right or left will result in full output.

The DSP guys can delay this signal for almost 20-22 ms and it will :

Raise sound stage

Help minimize rainbow effect.

Add ambiance

Widen stereo image

Lower distortion... the rears carry less information and so inherently have less distortion.

Give you a 3-dimensional sound field.

not hurt the front stage, it will enhance it.

[roms]

Surround from Rear Fill:
This method was used before the processing world came into play. It is Known as "Hafler's Matrix"
If you want to experience even more surround-type effects, wire your rear speakers according to the "Hafler principle":

1) Connect your front speakers normally to your amp.
2) Connect another speaker wire from the + terminal of your front right speaker to the + terminal of your rear right speaker.
3) Connect another speaker wire from the + terminal of your front left speaker to the + terminal of your rear left speaker.
4) Connect another speaker wire from the - terminal of your rear right speaker to the - terminal of your rear left speaker.

[mughal90]

Surround from Rear Fill:
This method was used before the processing world came into play. It is Known as "Hafler's Matrix"
If you want to experience even more surround-type effects, wire your rear speakers according to the "Hafler principle":

1) Connect your front speakers normally to your amp.
2) Connect another speaker wire from the + terminal of your front right speaker to the + terminal of your rear right speaker.
3) Connect another speaker wire from the + terminal of your front left speaker to the + terminal of your rear left speaker.
4) Connect another speaker wire from the - terminal of your rear right speaker to the - terminal of your rear left speaker.

After that will b a big explosion and there will b lots of sounds in ur surrounding

[mughal90]

Just kidding (H) have u tried this principle ?

[moonjee]

I like it, 99% of car audio in our market is coming from behind, I hope someone would take advantage of this informative thread and bring a revolution to his surround setup

Roms, please post implementation and results if you have already tried it. And keep it up, you are saving us a lot of time to go thorough long threads on diy hehe..

[roms]

Just kidding (H) have u tried this principle ?

I am running this setup and loving it

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[roms]

I like it, 99% of car audio in our market is coming from behind, I hope someone would take advantage of this informative thread and bring a revolution to his surround setup

Roms, please post implementation and results if you have already tried it. And keep it up, you are saving us a lot of time to go thorough long threads on diy hehe..

Yes i have tried it. The major plus u get is that the stage width and depth goes far beyond the boundaries of the vehicle. Thats what we want. By delaying a signal 20 to 22 ms or just before the Haas effect. The processor geeks have to invert one of rear channel from dsp to gain a perfect vocal cancellation effect. Because one channel is automatically inverted when bridge mode is used. This way you will get L -R signal.
The guys without a processor will use a Hafler's matrix method to get surround.

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[moonjee]

True, those who prefer rear speakers should go for this configurations since its tried and works well, would love to listen to your setup sometime, will give you a shout when I am around..

Processor guys don't all use surround, like myself.. No sound from the back boy.. We guys are always running short of channels on the DSP..

Yes i have tried it. The major plus u get is that the stage width and depth goes far beyond the boundaries of the vehicle. Thats what we want. By delaying a signal 20 to 22 ms or just before the Haas effect. The processor geeks have to invert one of rear channel from dsp to gain a perfect vocal cancellation effect. Because one channel is automatically inverted when bridge mode is used. This way you will get L -R signal.
The guys without a processor will use a Hafler's matrix method to get surround.

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[roms]

True, those who prefer rear speakers should go for this configurations since its tried and works well, would love to listen to your setup sometime, will give you a shout when I am around..

Processor guys don't all use surround, like myself.. No sound from the back boy.. We guys are always running short of channels on the DSP..

As you are running 3 way active with sub stage, if you can get 2 more channels from the dsp than you will be amazed how refills can change the game. Delaying them 20 ms, band pass them from 200 hz to 7khz with -6 db of attenuation will do the trick. The process i told without DSP is Hafler's matrix but you can do it even better to flip one rear channel to extract the L -R signal for surround.

[mughal90]

Roms bhai i think instead of climbing the SQ ladder one step at a time u should take a giant leap n get urself a DSP This statement is in response to the pic other day u sent me on wtsapp (H)

[roms]

Roms bhai i think instead of climbing the SQ ladder one step at a time u should take a giant leap n get urself a DSP This statement is in response to the pic other day u sent me on wtsapp (H)

Giant Leap ? No...Gradually ... Yes Because it gives more pleasure
I ain't gonna be using that thing, something else very soon

[asamieh]

Bro

U have an ideal system.. Inshallah will be building some what similar system soon.. currently busy in a couple of things by end of march or start of april will build a decent SQ system... I ll love to get a demo from you to listen to focal quality

[abdulwq]

Well described L-R signals:) you went thorugh whole thread on diy(A).L-R will fly from top, with most of us but it really enhances the system......Other simple way to enhance sound is to bridge refills in mono mode or using LP on refills will less interfere higher freq.

[roms]

Well described L-R signals:) you went thorugh whole thread on diy(A).L-R will fly from top, with most of us but it really enhances the system......Other simple way to enhance sound is to bridge refills in mono mode or using LP on refills will less interfere higher freq.

Well google is a teacher for all of us. The DSP can provide a straight solution for L -R, or Pro logic similar, the idea was to use refills to get the surround like we get in cinema and concerts.
The old method was the Hafler's matrix which i described earlier in thread. If none of above works for you than simply band passing the refills in between 200hz to 8khz with a delay of 22 ms or till the haas effect.

[Talhadon]

My detailed reply on auditioning this setup is still due on this thread ...... My DSL is simply annoying

[Bad_Cheetah]

Waiting for it Don

I spoke to haariso the other day, he told me some very nice things about the setup and Taimour Bhai's personality. I missed though, but InshALLAH next time

[roms]

My detailed reply on auditioning this setup is still due on this thread ...... My DSL is simply annoying

Talha i would love to take your feed back. Sort out your dsl

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