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Full Version: Maz's sound quality tip for the day!!
Mobile Electronics Australia > Mobile Electronics Discussion > Sound Quality Discussion
Maz
for those who dont have time delay or advance phasing adjustments, heres a tip.

Run your front stage with an 18db high pass crossover using caps and coils avilable from jaycar, anywhere from 70-85hz would be good, depending how good ur splits are.

wanna know why?

There is a path difference of about 3 metres between the sub and front stage, and the length of a 70-85hz wave is between 4 and 5 metres. SO the front speakers will be close 270degrees out of phase with the subs. By changing the polarity of the speakeryou can only go betwee0 180 and 360degrees out of phase.

so how does 18db crossovers help?

18db crossovers change the phasing of the speakers negative 90degree, so if you wire the subs to 360degrees phase with the sub the 90degree phase shift makes teh front stage 270degrees out of phase with the sub. As the front speakers due to the path difference of 270degree's also, there will be far greater constructive interfearance at the crossover frequency.

so whats this do? the midbass at the crossover frequency will improve, noticeably making the bass appear tigher and cleaner.

SO now the poor peopel can overcome the problem of awkward phasing.

*edit* this applies to all big large sedans that are either rearloading or firing directly into the cabin. I dunno the path difference of a hatch rear loading, i think it would be exactly 180degree delay.

Sedan rearloading, 270dgeree delay.
Sedan firing forward, 90degree delay
Hatch rear laoding would be inbetween so 180degree delay

laters

[ December 11, 2002, 14:46: Message edited by: Maz ]
raziel
can anyone tell me what an Alpine DREA-200 active crossover slopes at ? I thought it was 12dB - am I wrong ? I might give this a try ... I need something to do this weekend
shiny_car
yeah, 12dB/oct for both HP and LP.
JohnA
Are you sure about that Richard?????
shiny_car
smart@rse! *this is an 'in joke', sorry Members*



/spam
Wilf55
Another thing we dont get to know about by not being moderators...

Oh well, at least we dont have to pay 'mod fees' """
Maz
This is a simple test you can do to check if the 18db crossover will defintiely and noticable work.

Change the negative and positive of your sub and if the difference isn't very noticable then this is because the phase is inbetween 0 and 180 and somehwre close to 90degrees.

If you then put the 18db crossove ron and then swap the terminals over there should be a huge contrast when swapping teh sub phase around
Nikki
hey ok!! i dont know what anything of that mean
oh wells!
have a good one maz nik
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