Passive Line Filters (BD-Design)
by Bert 
, Friday, February 16, 2007, 16:34 (6289 days ago)
For people who do not understand how passive line filters work as implemented within all of our systems. I copied the text from a page present at the BD-Design site for a long time already:
All Oris DIY bass systems are "active" designs, requiring a dedicated amplifier (we recommend our BD30 DIY) and an active or passive (recommended) line level filter to match the bass system to an Oris horn.
The need for a separate amplifier is due to the very high sensitivity of the Oris horn (ranging from 103dB to 112dB depending on drive unit). A separate bass amplifier allows matching the lower sensitivity bass systems to the higher sensitivity horns. It also allows avoidance of the degrading effects of passive crossover networks, which are particularly bad for bass performance.
The active approach does require a line level filter to tune the bass to match the main horns. For this we recommend a passive filter design that draws a speaker level signal from the amplifier driving the main horns. This approach uses the bass amplifier as a "signal booster", reflecting the sonic characteristics of the main amplifier, and allowing for easy bass integration and some fine tuning of performance through the choice of amplifier.
I hope this helps to explain...
Ciao,
Bert
--
BD-Design - Only the Best!
Line Filters but related to SWINGS
Bert
Dare you to expose what plans you have with the RCA input on the control panel on the SWINGs. I understood it were dedicated for future digi-filters, replacing the passive ones?
Or does the question come too early?
GC
PS! Not manny letters can be inserted in the "Subject window". Might be useful for seperating the cross-talking and the real advert of the post?
Extension could maybe solve, to a certain extend, the disorientation among the threads.
Or is there a SW-based GPS device we could download.
Oh boy..this comment belongs to the "FORUM" topics... sorry....
Line Filters but related to SWINGS
by Bert , Friday, February 16, 2007, 21:28 (6289 days ago) @ GC
First, there is a Swing category you should use for this question, secondly (as mentioned by you also) there is also a category called Forum.
So why not use those options next time? 
Dare you to expose what plans you have with the RCA input on the control
panel on the SWINGs. I understood it were dedicated for future
digi-filters, replacing the passive ones?
The option I had in mind does not come through but still, the RCA gives you freedom to use a digital EQ, by-passing the passive line filter or whatever if you feel you need to experiment.
PS! Not manny letters can be inserted in the "Subject window". Might be
useful for seperating the cross-talking and the real advert of the post?
If made longer then the length will not fit in the board view overview (did you get that?) :wink:
Just open a new thread or topic if you feel that it is not on topic anymore. With a good chosen name then it will be clear and more easy to find back.
Ciao,
Bert
--
BD-Design - Only the Best!
Line Filters but related to SWINGS
GC,
Hi Bert
First, there is a Swing category you should use for this question,
secondly (as mentioned by you also) there is also a category called
Forum.
So why not use those options next time?
Why? Peter, what else?
Dare you to expose what plans you have with the RCA input on the
control
panel on the SWINGs. I understood it were dedicated for future
digi-filters, replacing the passive ones?
The option I had in mind does not come through but still, the RCA gives
you freedom to use a digital EQ or whatever if you feel you need to
experiment.
I have a suggestion. But you have to addess the "trash bin" topic to exchange the ideas. Dispite the heavy smooke in this department, torture and unfair low alcoholic drinks for the beef steaks are intoxicating this room.
Have you heard about the e-mail. And old recognised telegraf.
PS! Not manny letters can be inserted in the "Subject window". Might be
useful for seperating the cross-talking and the real advert of the
post?
If made longer then the length will not fit in the board view overview
(did you get that?) :wink:
Get another web-designer. No offence. Or is this also a DIY topic?
Just open a new thread or topic if you feel that it is not on topic
anymore. With a good chosen name then it will be clear and more easy to
find back.
Oke Doke. I'll do that.
GC
Passive Line Filters
Bert
it would help if you would also show the values for the filter components.
someone at CES did calculate these values for me for cut 220hz to mach the orpheans, and a friend of mine made them for me. but they don't work. I don't know the reason, if it is because the values are wrong, ore something else.
It seems very easy to built, but for people like me who do not understand anything abought building filters, it's not. If you would offer it ready for sell, i think many customers would prefere to buy them from you, instead to make them by their own, ore search someone to built them.
rds Angelo.
Passive Line Filters
by Bert , Saturday, February 17, 2007, 09:34 (6288 days ago) @ angeloitacare
Hi Angelo,
it would help if you would also show the values for the filter components.
That will be of no use if the filter is used with something else than what I am offering. As far as I can remember you are using Klipsch corner horns for the bass and as I told you before, these do not work optimallly due to some basic problems.
Their path length is too long (time delay) and their frequency response is hardly flat (frequency and phase) especially when used in a small room.
It is impossible for me to make a filter for such a situation simply because it has to be specifically tuned for your room.
someone at CES did calculate these values for me for cut 220hz to mach the
orpheans, and a friend of mine made them for me. but they don't work. I
don't know the reason, if it is because the values are wrong, ore
something else.
Can you send me a drawing or picture of that filter and the connections you made? What do you mean it does not work, no sound?
Ciao,
Bert
--
BD-Design - Only the Best!
Passive Line Filters
hi Bert
i am well aware of the problems of the K-horns, . i thought that using your filter, it would get things a little better. i do not have the values of the capacitors anymore, i left them with my friend. rds Angelo
![[image]](images/uploaded/image213.jpg)
Passive Line Filters
by Bert , Saturday, February 17, 2007, 13:29 (6288 days ago) @ angeloitacare
Hi Angelo,
i am well aware of the problems of the K-horns, . i thought that using
your filter, it would get things a little better. i do not have the values
of the capacitors anymore, i left them with my friend. rds Angelo
Looking at the capacitors.... you use very high values! Are you sure that the calculations were done properly? What is the value of the resistors? The picture is not clear enough to see the colour of the code rings...
Normally I use 1/1000th value for the C's than the ones shown on your picture and also better quality ones and certainly not electrolic types.
Ciao,
Bert
--
BD-Design - Only the Best!
Passive Line Filters
Bert
Looking at the capacitors.... you use very high values! Are you sure that the calculations were done properly?
i really dont know. i just gave the values the guy calculated for me to my friend and asked him to make the filter with the informed values.
What is the value of the resistors? The picture is not clear enough to see the colour of the code rings...
the black one says log 25ml 50 vcc the gray ones say 25v 33micro farad, and the 3 small ones have no numbers, only the ring colors.
Normally I use 1/1000th value for the C's than the ones shown on your picture and also better quality ones and certainly not electrolic types.
u see, not even using the right components, makes things even worse, to get a decent result.
aes kassel is offering a line filter from you ( i dont know why u dont offer it at your own site too )
Der Line-Filter arbeitet mit einer Flankensteilheit von 24dB/Oct. , und das nahezu Phasenstarr, was man sonst eigentlich nur von Aktivweichen her keGCt. Die obere Grenzfrequenz wurde für die jeweiligen Oris-Hörner wie 150, 200, 250 bzw. dem Orphean optimiert. Dieser Filter ist somit ein unbedingtes "muß" für jede Hornkombination.
would it not resolve what i want to do ?
rds angelo
Passive Line Filters
by Bert , Saturday, February 17, 2007, 15:55 (6288 days ago) @ angeloitacare
Angelo,
aes kassel is offering a line filter from you ( i dont know why u dont
offer it at your own site too )
I wish life would be that easy...
If it would be that simple then I would have such a basic filter for sale too. The filters I supply in combination with my products work as they should, using other components will make the filters hardly optimal.
I prefer to support my own products and spend my time with that (I know what these are all about and therefore perfectly able to find a solution).
Do not expect me to help people with their problems for choosing other components from which I do not have any specification or experience with.
It is not that I do not want to help, I simply can't. Too many unknown parameters to work with...
Der Line-Filter arbeitet mit einer Flankensteilheit von 24dB/Oct. , und
das nahezu Phasenstarr, was man sonst eigentlich nur von Aktivweichen her
keGCt. Die obere Grenzfrequenz wurde für die jeweiligen Oris-Hörner wie
150, 200, 250 bzw. dem Orphean optimiert. Dieser Filter ist somit ein
unbedingtes "muß" für jede Hornkombination.would it not resolve what i want to do ?
Perhaps at AES they found the solution for all problems with their basic filter, so ask them.
Their filter solution might look similar to the ones I use but they did not get their filter idea (for general use) from me, neither did they asked me if that could work well.
Ciao,
Bert
--
BD-Design - Only the Best!
Passive Line Filters
Angelo...sorry for interupting here...
the black one says log 25ml 50 vcc the gray ones say 25v 33micro farad,
and the 3 small ones have no numbers, only the ring colors.
My man..What is the input impedance of the amp this line filter is used for?
Is it a "normal" 10 or 47 KOhm or?Ohm? input?
The guy who calculated this filter for you, must have asked you before calculation.
I think I passed a few hints to you discussing your commercial project.
I'm just guessing wild now: You might have consulted the wrong "expert" here. (Not you Bert)
You caNot calculate a filter that would be of any use for anything at all.
Take this advice: Draw some bucks out of your wallet and find one who really knows what he's doing. And pay him what it takes.
Der Line-Filter arbeitet mit einer Flankensteilheit von 24dB/Oct. , und
das nahezu Phasenstarr, was man sonst eigentlich nur von Aktivweichen her
keGCt. Die obere Grenzfrequenz wurde für die jeweiligen Oris-Hörner wie
150, 200, 250 bzw. dem Orphean optimiert. Dieser Filter ist somit ein
unbedingtes "muß" für jede Hornkombination.would it not resolve what i want to do ?
But who could know that when the amps impedance is not known? Neither the freq. behaviour of your Klipsh horns.
Angelo...what are you doing with all respect?
GC
Passive Line Filters
GC
this has nothing to do with my commercial project.
i use k-horn bass at home, but since i have the orpheans, it works without crossover. so i want to built a filter for them to perform better.
rds Angelo
Passive Line Filters
by Bert , Saturday, February 17, 2007, 18:53 (6288 days ago) @ angeloitacare
Dear Angelo,
Try this filter.
![[image]](images/uploaded/image37.gif)
And let me know how this sounds (and where the sound should be improved). The 100k resistor should be a potentiometer to control the volume of the bass if your bass amp doesn't have its own.
The used resistors as shown on your picture will do, the capacitors should be minimal MKT's.
The Orphean should be connected in the same polarity as the K-horns but for the experiment you can also try it in the opposite phase.
Ciao,
Bert
--
BD-Design - Only the Best!
Passive Line Filters
hi Bert
thanks for your help and effort. I will see if i find the components ,let it build locally from someone, and see if it improoves the sound.
rds angelo
Passive Line Filters
by Bert , Saturday, February 17, 2007, 19:26 (6288 days ago) @ angeloitacare
Angelo,
thanks for your help and effort. I will see if i find the components ,let
it build locally from someone, and see if it improoves the sound.
My pleasure, but do not expect that this filter will work optimal at first. I will need some specific feedback after you have experimented with the filter so that I can give some suggestions to improve it.
Just telling me that is sounds worse or better doesn't do it for me if you want to get most out of your less optimal situation.
I do hope that you understand where and how to connect the filter? Here is a reminder...
http://www.bd-design.nl/index.html?lang=en-uk&target=d89.html
Ciao,
Bert
--
BD-Design - Only the Best!
Passive Line Filters
Hi Bert..
I just found that thread, what can i say...
i think i bought something wrong with my AES-LineFilter, nobody asked me about what amp follows.
This is what i found inside my LineFilter:
![[image]](images/uploaded/image418.jpg)
The following amps are SAC Igel 50T (upgraded):
Input resistance: 22kOhm
Input voltage / output: 1 Volt
Output resistance: 3mOhm
Damping factor (20Hz-20kHz): >600
It must be a little wonder if that works right:wink:
Of course i saw your posts above about AES-products, even this LineFilter. And of course i understand your position. But i don´t want to buy something wrong again, so i ask your for help
Best Rgds..
Ralph
Passive Line Filters
by Bert , Wednesday, February 06, 2008, 10:07 (5934 days ago) @ Balthasar
Hi Ralph,
I can't help much but I am sure that AES tested this with their bass system and your Oris horns/drivers.
You can always try to tune it by changing one or more values for the capacitors and listen if things improve. Having a different input impedance with your amplifier does change the filter character but to which extend (and if it is working less optimal) depends on the situation.
The effect of making the capacitors bigger lowers the crossover frequency (less midbass or overlap), making the smaller will cross higher (more midbass or overlap).
Bert
--
BD-Design - Only the Best!
Passive Line Filters
Hi Angelo
this has nothing to do with my commercial project.
I know.
:wink:
i use k-horn bass at home, but since i have the orpheans, it works without
crossover. so i want to built a filter for them to perform better.
I can see from Bert's filter suggestion you have a seperate amp driving the K-horns.
You also see that the suggestion from Bert difers quite a lot from the filter the other guy suggested you.
I feel 250% sure that Bert's proposal will improve the sound by miles.
Enjoy 
GC