Low Frequency Filtering (Off Topic)

by jdubs @, Sunday, April 23, 2006, 22:47 (4286 days ago)
edited by unknown, Sunday, April 23, 2006, 22:59

Hello All

I'm currently using Oris 150s with AER MD-3 drivers.

I listen to all sorts of music at varying volume levels. I'm currently running the horns at full-range, but would like to try to filter the really low frequencies in an effort to protect the drivers.

What is the best way of accomplishing this?

Thanks!
Jim

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Low Frequency Filtering

by Bert @, Monday, April 24, 2006, 00:24 (4286 days ago) @ jdubs

Hi Jim,

I'm currently using Oris 150s with AER MD-3 drivers.

Do you use the passive line filter approach or do you use an active filter for the bass?

What is the best way of accomplishing this?

If you use the passive line filter then you could add a effective 12dB passive filter in between the AER and the connections going to your bass amplifier. To make this filter work you'll also have to add an RCL impedance correction to reduce the impedance peak around 150Hz. If you do not do this then the filter will not work properly and is practically boosting this frequency....

If you have an active filter then the most simple way is to add a passive line filter in front of the amp that is driving the AER's. In that case there is no problem to expect with impedance peaks.

This peak is not always the same, it changes when you use the back cover or not and if you use the reflex port or not....

How is your back chamber configured?

Ciao,

Bert

--
BD-Design - Only the Best!

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Low Frequency Filtering

by jdubs @, Monday, April 24, 2006, 03:56 (4286 days ago) @ Bert

Thanks Bert! I'm using a Marchand XM-44 in front of the amp driving my bass cabinets. Crossover is at 160hz. with a 12 db. slope. The crossover is driven off of one set of preamp outs....the other set of preamp outputs drives the amp which then drives the horns (full range).

Do you have the recommended specs for such a filter?

Do you think I should even bother given that I'm not watching movies with these speakers?

Btw, the back cover is currently on and the reflex port is in place...but it doesn't sound like that matters given that I'm using an active solution in front of the bass cabinets.

Thank you Bert.

-Jim

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Low Frequency Filtering

by Bert @, Monday, April 24, 2006, 09:39 (4285 days ago) @ jdubs

Hi Jim,

Do you have the recommended specs for such a filter?

In your situation you can replace the input capacitor of your amplifier (for the AER's) to a much smaller one. That will already limit the lowest frequencies. The value needed depends on the input impedance of that amp but you can try to decrease the value until you detect changes in the low mids (less bodied). With that value you have protected the driver more and made life more easy for the amp too.

You can start with 100nF and double or half the value until you have found the smallest without hearing too much change.

Do you think I should even bother given that I'm not watching movies with
these speakers?

A simple test is to play a record with very deep bass and turn up the volume while checking the movement of the AER. If it is not moving much on your listening level then there is nothing to worry about... :)

Ciao,

Bert

--
BD-Design - Only the Best!

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Thanks Bert!

by jdubs @, Tuesday, April 25, 2006, 03:55 (4285 days ago) @ Bert

Hi Jim,

Do you have the recommended specs for such a filter?


In your situation you can replace the input capacitor of your amplifier
(for the AER's) to a much smaller one. That will already limit the lowest
frequencies. The value needed depends on the input impedance of that amp
but you can try to decrease the value until you detect changes in the low
mids (less bodied). With that value you have protected the driver more and
made life more easy for the amp too.

You can start with 100nF and double or half the value until you have found
the smallest without hearing too much change.

Do you think I should even bother given that I'm not watching movies

with

these speakers?


A simple test is to play a record with very deep bass and turn up the
volume while checking the movement of the AER. If it is not moving much on
your listening level then there is nothing to worry about... :)

Ciao,

Bert

Great, thank you Bert! You know...I've RARELY seen those AERs move...and when they do, its such a minute amount! I think I'll keep them going full-range for now. :smile:

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