What's Phase Shift Controller Do??

[A20 LEE 0]

As above and do i need one? Heard there pretty cool.

[dr_mat 0]

I'm guessing you don't mean in the audio sense...

[A20 LEE 0]

I'm guessing you don't mean in the audio sense...

 

Definately in the car audio sense. Lookin' through brochures, looks cool, doesn't say what it does.

[Supercharged 2]

I would have thought it would adjust the timing on the signal going to different components like a sub so you can move it's phase in time with the rest of the setup, say if its on it's own amp and its response is a bit slow etc...

[dr_mat 0]

That would make sense. Particularly if you have a stretch limo with the sub in the boot... In a corrado though? Suppose it makes sense for high frequencies, to retain stereo imaging, but not the bass. The wavelength is >> length of car..

[Kevin Bacon 5]

Phase shift comes built in to most headunits. Not sure what you mean by 'controller' though.... It saves you having to climb in the boot and swap the sub's speaker wire polarity over.

 

Most people find flipping the sub 180 degrees out of phase deepens the bass and opens up the front stage considerably.

[dr_mat 0]

You mean it decouples the sound from what's coming out of the front speakers, in the same way that listening to dolby pro-logic encoded sounds on a non-pro-logic playback system sounds like it has a weird gap in the middle? Or do you mean it's used because it's easier to hit the phase invert switch than to swap the wires over?

I'm not an expert, but I have to say it sounds like snake oil to me... ;)

I know "serious" hifi often has a phase invert switch, but that's to invert the WHOLE phase at the same time, you never see people suggesting splitting the signal and inverting bits of it and not other bits, the idea is that it forms a cohesive whole, not a disjointed bunch of sounds.

[Kevin Bacon 5]

Yes, easier to hit the switch than swap the wires over! I know exactly where you're coming from with the other bumpf, being an avid domestic audio fan myself, but I'm afraid it's meaningless in a car.

 

Domestic Audio is a piece of P to set up. ICE is a totally different ball game....

 

Some Hi end headunits also allow you to invert the phase on each channel, not just the sub. I run my sub out of phase and also the tweeters and it sounds a lot better. I've also time delayed the offside components by 0.5ms to shift the staging into the centre of the screen. When I get round to full active, I will also be able to time delay the mids in relation to the tweeters to overcome the delays due to their positioning to eachother..... cool stuff 8)

[dr_mat 0]

Home audio is only simple because it's designed that way - you have one box, with all the speakers in it, so all the frequenciesof sound come from the same place!

[Kevin Bacon 5]

Well yeah and you don't have 70mph road rumble to contend with either!

[dr_mat 0]

Unless the wide boy with the LOUD beetle is trying to park (badly) outside your living room window (the joys of terraced housing)... Forget road rumble it's not as intrusive as "crap exhaust" noises... :)

[pablo_vr6 0]

the more advanced controllers allow an analogue phase shift - not just a simple 180 swap. I believe the idea is to allow integration of the sub to the front speakers as the sub should appear to come from the centre of the dash and SHOULDNT sound like its coming from the boot.

 

obviously the distance from front to sub will be different for each car so an analogue adjustment is ideal.

 

never used it much myself tho. swapped the phases around on speakers sure but never had call for the fancy gubbins.

[coolrado 0]

bass is not as directional as mid range and treble so it would be difficult to make the sub sound like it was in the dash. the bass should really sound as if it is around you not in front of you.

when i had my sub inverted (basket out) it did sound better when i flipped the phase by 180, but when i put the sub back in the normal way round it sounded like it was fighting against the other drivers and sounded pretty bad untill i flipped the phase back to normal.

 

it can be very difficult to set up home audio especially when you start getting into dts ES or full THX EX systems where the placement of the speakers is crucial to the overall sound.

and when you have one of these it gets even more tricky :lol:

[Kevin Bacon 5]

The bass will always sound like it's coming from the back - because it is in the back. You just need to be careful with where you cross it over as bass becomes directional at about 80Hz... X it over low enough and it won't be so *noticably* in the boot!

[pablo_vr6 0]

damn thats COOL!!

 

the bass should sound ike its coming from the stage which should be on the dash ;)

[coolrado 0]

damn thats COOL!!

 

the bass should sound ike its coming from the stage which should be on the dash ;)

 

when you go to see most bands play live the bass is very hard to localise it dosnt appear to come from one spot

 

a mate of mine who is a drummer and producer for quite a well known 90's band has spoken to me about this before and said that when they set up the bass drivers at most of the gigs they place them more towards the side of the stage and audience as the bass is not directional, he said if you close your eyes when a bass note is being played it should be difficult to pin point where the sound is coming from

 

but as a car is more enclosed i suppose its harder for the bass to spread as much and so will sound more localised

[pablo_vr6 0]

as long as it doesnt sound like a big thump from the boot all is good :)

[dr_mat 0]

Bottom string on a bass guitar is around 53Hz (IIRC), so the fundamental tone won't be locateable to the human ear (which works by phase-shift differentiation aswell as pure amplitude differentiation). All the harmonics *will* be locateable, however, but they should be being delivered by your front speakers, not your subwoofer.

Long and short is that if your sub sounds like it's in the boot, the frequency cut-off is set too high!

 

Be interested to see how you do an analogue variable phase shift circuit too! Frequency dependant time delays?

[Supercharged 2]

A20 LEE, I bet you wished you never asked! :lol:

[A20 LEE 0]

A20 LEE, I bet you wished you never asked! :lol:

 

Interesting to get other opinions. From what i understand though lookin' on a few forums seems its more to do with full range rather than bass. I think jist of the box is a left to right fader with phase shifting and a variable delay. I'm guessing its all about balance the front components.

[pablo_vr6 0]

Ive only really seen them on bass/sub controllers tho. maybe its just me

[CoxyLaad 0]

f*ck me, and I thought phase shift was something that occured once on an episode of star trek.....

[dinkus 10]

Phase is just the delay between one signal and another, so a phase 'shift' box controller just introduces more or less delay. Nowt that exciting, but it does have to be pretty accurate ;)

 

Now optical delay units that used to be used as anaolgue frame stores for video... now that's one clever bit-o-kit :D