Changing the Subs LPF frequency range . - AVS Forum | Home Theater Discussions And Reviews
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post #1 of 8 Old 10-31-2008, 03:09 PM - Thread Starter
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Hi.

Can I lower the frequency range of the LPF from say 50-100HZ
to 40-80??

Anyone did it before?
Should i decrese the value of the resistor after the potentiometer by 20%?


Thanks!
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post #2 of 8 Old 10-31-2008, 06:01 PM
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Huh? To what resistor are you referring??

If you're using a plate amplifier built into your subwoofer, are you saying that it's adjustable crossover only can be set between 50 and 100Hz? If so, to what frequency are you wanting to set it? Do you think there will be a significant difference using 40Hz as opposed to 50Hz?

Regardless of all that, if you're using a 5.1/7.1 capable surround receiver/preamp to feed the subwoofer, then it will have it's own crossover built-in, and you don't need to use the one within the subwoofer amplifier at all.

So what exactly are you trying to achieve?
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post #3 of 8 Old 11-01-2008, 01:56 AM - Thread Starter
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Yes, the one at the plate amp...
I have a monitoring system which is capable till 45HZ and i wanna extand it
with subwoofer to 20HZ.

all i need to do is to adjust the frequency range of the sub from 50-100 to 40-80HZ
in order to calibrate it to my monitors...

is it that simple? just changing the resistor?
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post #4 of 8 Old 11-01-2008, 12:28 PM - Thread Starter
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p.s

i'm talking about the keiga KGD-5230.
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post #5 of 8 Old 11-01-2008, 12:33 PM
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Quote:
Originally Posted by -Barak- View Post

Yes, the one at the plate amp...
I have a monitoring system which is capable till 45HZ and i wanna extand it
with subwoofer to 20HZ.

all i need to do is to adjust the frequency range of the sub from 50-100 to 40-80HZ
in order to calibrate it to my monitors...

is it that simple? just changing the resistor?

You still didn't mention what kind of receiver/preamp you're using. If it's anything recent, it likely already has a subwoofer crossover built in, possibly adjustable.

If you want to change the subwoofer amplifier's crossover, you'll need to get technical documentation describing such modifications. So which amplifier is your subwoofer using?
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post #6 of 8 Old 11-01-2008, 12:54 PM - Thread Starter
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http://www.keiga.com.tw/20070116_KGD...KGD5230_X2.pdf

Don't have recievers/Preamps...
just 2 powered monitors fed by DAC ("Apogee mini-dac")
i wanna use the other "line out" output of the dac to connect the powered sub and cut it around
45HZ... (maybe 1-2HZ lower)
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post #7 of 8 Old 11-01-2008, 04:57 PM
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I really do not think most people could hear a difference in a 45hz crossover compared to 50hz.

You could run your speakers full range (seems you don't have a way to cross them) and then just cross your sub at 50hz, that shouldn't sound bad at all. For most crossovers, the actuall crossover point is already -3dbs down anyways. So if you were to cross at 50 hz, you might have about 1dbs extra output from 45-50 hz, and I really don't think that is noticable at all.

But thats just me, i suppose if you keep searching you can figure out how to make a 43-45 hz crossover possible.

But if you havn't listened to it already I would suggest doing that first, it may be just fine.
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post #8 of 8 Old 11-01-2008, 05:39 PM - Thread Starter
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I tried what you said last week with sub i took from
a friend. it has same 50HZ minimum cut...

It seems that one note of the bass guitar/contrabass and some +-50HZ
bass drums sounds clearly louder, i'd rather mix without a sub than
mix badly.

i know i will be able to tune it right, if i had a little lower frequency cut.
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