12 replies to this topic

[Brucee]

Hi guys, just a quick question, when u set your car audio, do u set the TA first or the EQ first? i found it very confusing, cos when you set the TA first, then EQ the car using RTA, the TA will be change, but if u EQ first using RTA then TA, when you see the result using RTA, the whole nice flat EQ before the TA will be change dramaticly

so should the TA follow the EQ or the other way? thanks

[shiny_car]

i always set the TA first. it doesn't 'change' when you tune the EQ in alpine HUs. not sure what you mean there.

[Pulse-R]

TA first, otherwise you have "group delay nulls" (sort of phase cancellation at the crossover frequency), which the EQ cannot 'fix' without causing much yuck.

if you can set the TA to give peaks at the crossover frequency, this is often a good indication that the TA is correct. however, you then may need to 'underlap' the crossovers to reduce the peaks but EQ can do this too.

changing the crossover frequency can also change the phase of the signal at the crossover by some amount, so the TA may seem wrong, but instead it is the crossover which needs to be changed.

the acoustic crossover point is often not the same as the electrical crossover point, due mainly to the frequency response of the speakers, and the car's acoustic environment.

you need sophisticated test gear, or good ears, to set the crossovers properly...

[Juls]

I always do it in this order.

1. Basic Time Alignment (as per manual)
2. Basic EQ (get reasonably nice response)
3. Advanced Time Alignment (for staging and imaging)
4. Advanced EQ (For sound linearity, and image definition, Staging accuracy.)

if your using active crossovers, then there is a modified approach, which requires about 7 steps or so.

Juls

[Brucee]

thanks for your help guys, i'm using ATB PC RTA to analyse the graph, also when i'm using the formula longest distance speaker(in M)-speaker that when want to measure divide by 343 and times 1000 (basic formula for TA) i always get the feeling that the singer is right in front of me, not in the centre of the dasboard, how to fix this? so far i always fix it manualy (ex add another 1 or 2 ms to the right speaker), is there any other way?

btw the system is full active using Alpine F#1, so there's no pasive crossover, so far my main problem is to properly set the TA.

Also in my F#1, there SSSSSSSSSSSSSSSSSSSSSSS noise, quite loud, why is that? before i use Pioneer DEQ P9, with same system, same wiring, there's no noise, is it my F#1 defect or is there another couse?

thanks

[Powerband]

First of all agree with above, TA first then EQ

Brucee, on Jan 1 2007, 12:59 AM, said:

...I always get the feeling that the singer is right in front of me, not in the centre of the dashboard, how do I fix this? so far I always fix it manualy (eg add another 1 or 2 ms to the right speaker), is there any other way?

Could be the speaker position, ie Are the speakers facing each other or toward you?

Sometimes one way is better than the other, depends on what type of speakers you have. Some speakers don't have very good sound from the side (there's a term for it, can't remember right now) EDIT: "off axis response"

Brucee, on Jan 1 2007, 12:59 AM, said:

Also in my F#1, there SSSSSSSSSSSSSSSSSSSSSSS noise, quite loud, why is that?...does my F#1 have a defect or is there another cause?

I got a bit of this when I first installed my HX-D2 but didn't notice it after a while. I'm sure its something to do with running active. It has been discussed in the forum before, so do a search and you may find the answer. (look for "sibilance", not correct but might steer you in the right direction) I think it is solved with equalising but hopefully someone can give you a more accurate answer

cheers

Edited by powerband, 02 January 2007 - 02:30 AM.

[Pulse-R]

what F#1 ?
should be no noise.

[shiny_car]

Brucee, on Jan 1 2007, 01:59 AM, said:

so far i always fix it manualy (ex add another 1 or 2 ms to the right speaker), is there any other way?

i always finetune 'manually'. no better way.

however, have you tried the F#1 auto setup features? how did that sound?

[Brucee]

yup, i've try the auto set up, sound quite flat, with singer right in my face, nothing special, the auto set up work exacly like PXA-H700 btw this is the new F#1 (somehow i got the feeling that the old F#1 is better lol)

the speaker location are
tweeter in the dasboard on-axis,
mid range in the upper door, facing each other
mid bass in the factory location

speaker is visaton (mht 12 ribbon tweeter, ti 100 titanium midrange & al 170 alumunium midbass) with each pair drive by phass re 50
the car is honda new civic 2006

i still can find the cause of the SSSSSSSSSS noise, i change back the HU to the pioneer DEQ P9 and the SSSSSSSS noise is gone, change back to F#1 and the noise is there, realy drive me crazy

btw in my area , my car is the only one that running active using F#1, is this realy the cause of the SSSSSS noise? cos i heard another car also using F#1 but running pasive, and there's no noise

[Brucee]

one more thing, i've put the amp gain to zero, turn off the speaker from the HU , and the SSSSSSSSSS noise is still there, so definetly this got nothing to do with EQ, i mean the amp gain is ZERO and the speaker is off, but why still got SSSSSS noise? doesn't make any sense

[Powerband]

It's something to do with being active

I've read other people have the same problem but I can't remember the remedy. Can you try your system passive to see if the hiss is still there?

I just did a search using 'ssss noise active' and came up with these

http://www.caraudioaustralia.com/forums/in...se+active+sssss

http://www.caraudioaustralia.com/forums/in...=69952&st=0

http://www.caraudioaustralia.com/forums/in...se+active+sssss

http://www.caraudioaustralia.com/forums/in...se+active+sssss


Hope you find some answers

cheers

Edited by powerband, 02 January 2007 - 02:52 AM.

[Pulse-R]

maybe the input impedance of the amps is not matched to the Alpine output - just a thought, so you don't get full quieting of the outputs... I saw something about this on another car audio forum - they pull apart the F#1 and some other stuff and look at the guts and comment on it.

[Brucee]

ok, thanks for your helps guys, apreciate it