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Old 27th December 2007, 10:05   #16
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Originally Posted by clipto333 View Post
Navinji, what will happen if one just use a single resistor in series or parellel? i think only the impedance will go up. do amps have a problem driving high impedance speakers?
There is a good reason why Lpad have a parallel and series resistor. Usually Lpad are palced between the tweeter and it's crossover. why? really I have no answer to that. it maybe be becuase at this point since much of the energy is HPFed you can use smaller components.

Anyway when a Lpad is so placed (between tweeter and it's crossover) the crossover see the effective impedance of teh Lapd+tweeter. If one only used a series resistor to execute a "Lpad" the effective resistnace would change and the crossover would be now operating a frequency different from the one it was suppsoed to operate at. using a series+parallel combo ensures that while the tweeter is attenuated the efffective resistance as seen by the tweeter's corssover is still the same.

let see...
assume a 4 ohm tweeter. now if you add a 4 ohm resistor in series to it the corssover will see 4+4 ohms = 8 ohms. Instead if you add a 1 ohm resistor in series and a 12 ohm resistor in parallel with the tweeter the corssover will see 4 ohms. (4//12 = 3ohms + 1 ohm = 4 ohms).

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Originally Posted by maverickzCar View Post
Navin ji, pls check the above pics. What do you think of such setup?
I see 2 problems
1. some smear from the windshield
2. if your car clear is over zealous it might knock the tweeter off.
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Old 27th December 2007, 11:40   #17
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... I see 2 problems
1. some smear from the windshield
2. if your car clear is over zealous it might knock the tweeter off.
Smear apart, intuitively it looks like the tweeters will dump their total energy ON-AXIS (efficient reflection from the windscreen glass) into the listeners' ears in the current location.

Perhaps a simpler solution for him would be to shift them to the mirror pod or the bottom of the A-pillar FRP cap or the door pad (whichever is convenient), as long as they are facing each other.
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Old 27th December 2007, 13:59   #18
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Navin sir, can u pls give your thoughts on my other ques as well - how much SQ will be affected by going for 6x9? Any specific negatives with such setup (except enduring a tray module in already cramped rear view)??

DerAlte, dont know if you wud call it noob-ism, but am not able to get hold of these locations (bottom of the A-pillar FRP cap or the door pad). I saw a post by HorsePower where he has placed tweeters at the bottom near door-speakers (http://www.team-bhp.com/forum/sound-...tml#post476487)

Are you referring to the same? Also, you recommended mirror pod...aint my tweeters near mirror pod right now also?? There must be an ideal location for tweeters for a car like Swift, can someone shed light on that?
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Old 27th December 2007, 15:46   #19
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Originally Posted by maverickzCar View Post
Navin sir, can u pls give your thoughts on my other ques as well - how much SQ will be affected by going for 6x9?

Are you referring to the same? Also, you recommended mirror pod...aint my tweeters near mirror pod right now also?? There must be an ideal location for tweeters for a car like Swift, can someone shed light on that?
ref 6x9: the Swift has very little room on the rear deck for the 6x9s. 6x9s on a MDF rear deck will provide more bass than 6" in the door but from what Gunbir tells me the difference is marginal. I dont own a Swift and hence am inclined to belive him.

ref tweeters: angle the tweeters so that the driver's left ear is on axis with the left tweeter and the passenger's right ear is on axis with the right tweeter. this will automatically ensure that the tweeters are not facing the windshiield.
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Old 27th December 2007, 18:09   #20
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Originally Posted by navin View Post
There is a good reason why Lpad have a parallel and series resistor. Usually Lpad are palced between the tweeter and it's crossover. why? really I have no answer to that. it maybe be becuase at this point since much of the energy is HPFed you can use smaller components.

Anyway when a Lpad is so placed (between tweeter and it's crossover) the crossover see the effective impedance of teh Lapd+tweeter. If one only used a series resistor to execute a "Lpad" the effective resistnace would change and the crossover would be now operating a frequency different from the one it was suppsoed to operate at. using a series+parallel combo ensures that while the tweeter is attenuated the efffective resistance as seen by the tweeter's corssover is still the same.

let see...
assume a 4 ohm tweeter. now if you add a 4 ohm resistor in series to it the corssover will see 4+4 ohms = 8 ohms. Instead if you add a 1 ohm resistor in series and a 12 ohm resistor in parallel with the tweeter the corssover will see 4 ohms. (4//12 = 3ohms + 1 ohm = 4 ohms).
that could be the reason. otherwise one will have to use higher wattage resistors and they are quite huge.

thanks for the explanation. you are really an institue. :-) is there a tolerance level? like in %? one can't get the exact resistance. there will always be a marginal error IMO.

thanks again. how do you calculate attenuation? what will be the att if we add the above resistor i.e. 12 ohm in parallel and 1 ohm in series?

cheers
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Old 27th December 2007, 18:45   #21
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Originally Posted by clipto333 View Post
thanks for the explanation. you are really an institue. :-)

thanks again. how do you calculate attenuation? what will be the att if we add the above resistor i.e. 12 ohm in parallel and 1 ohm in series?
yes my wife tell me something similar too "you ought to be instituted"! :-)

calculating attentuation is rather simple.

first you use Kirchoff's current law
say 4//12 that means 1/4th of the current will pass through the 12ohm resistor and 3/4th through the 4 ohm resistor. so say you have 3W across the tweeter/12 ohm resistor combo (3 ohms = 1A) only 0.75amps is going thru the tweeter...I dont have the log tables but you can figure out the attenution in db using that.

when you have 1ohm in series with 3 ohms use Kirchoff voltage law...and you get further attention..

or if you are really lazy go here
L-Pad (Driver Attenuation Circuit) Designer / Calculator

you will find my numbers will give you about 2.5db (close enouugh an approximation for 3db) attenuation. the thing is I have been doing this stuff so long the numbers just come as i type. sorry for not providing an explanation earlier.

Last edited by navin : 27th December 2007 at 18:47.
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Old 27th December 2007, 21:00   #22
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Originally Posted by maverickzCar View Post
Guys, After lots of late night sittings on TeamBHP, finally for my Swift, I got Pioneer 7950UB and Hertz speakers installed this monday from Driven. And somehow, it seems, sound is not at all convincing...

Right now, am not going for an Amp...hence speakers is all i got to give me a smile! So, kindly dont suggest an Amp as solution to all these pains...or is it something just inevitable??? I will go to Driven again so will try out any changes that you guys here suggest - brand, location of speakers, anything...But, give me some sound which allows me to shake my head without buring pocket holes!

at the cost of sounding stupid, pl check the bass and treble levels, or any other pre-set EQ in the HU. i'm not sure if in deici the crossover has levels, you could set them up as well. getting a pre-amped base thingy would a better solution than 6x9s esp for swift. a 4 channel amp would be ideal, with 2 channels for the front comps, one for the sub, and rear co-axs on HU. check if the woofers + and - have been wired correctly from each crossover... it's human to err and divine to forgive.
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Old 28th December 2007, 01:03   #23
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at the cost of sounding stupid, pl check the bass and treble levels, or any other pre-set EQ in the HU.
Maverick, please let me know next time you visit DRIVEN. I will drop by and see whats wrong.

Cheers!
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Old 28th December 2007, 10:58   #24
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Maverick, please let me know next time you visit DRIVEN. I will drop by and see whats wrong.

Cheers!

see! thats the best part of being a TBhpian....
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Old 28th December 2007, 15:15   #25
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Montyguru, I did all those EQ trials already.

Gunbir, sure man, will keep you in loop regarding my Driven visit. Thnx.
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