Passive Line level crossovers are available
the XM46 by Marchand is a passive line level crossover for specified frequencies.
http://www.marchandelec.com/xm46.htm
This looks like pretty good value. There will be some insertion loss which should not be a problem if your preamp has enough gain.
Looks good enough to me that I am very close to purchasing several.
Most Plate amp crossovers wil not go as high as 200hz crossover point, plus the plate amp itself usually rolls off at a pretty steep rate - this might be good or bad depending on what you are trying to achieve -
HTH
Ken L
the XM46 by Marchand is a passive line level crossover for specified frequencies.
http://www.marchandelec.com/xm46.htm
This looks like pretty good value. There will be some insertion loss which should not be a problem if your preamp has enough gain.
Looks good enough to me that I am very close to purchasing several.
Most Plate amp crossovers wil not go as high as 200hz crossover point, plus the plate amp itself usually rolls off at a pretty steep rate - this might be good or bad depending on what you are trying to achieve -
HTH
Ken L
A pretty inexpensive solution seems to be available here. This website is run by Planet 10, the moderator on this forum:
http://www.t-linespeakers.org/tech/filters/passiveHLxo.html
These are useful if you have an amp just to run the subwoofer. They are placed before the subwoofer amp. I haven't tried one, but if this is the way you want to go, try listing the values that you plan to use and the electronics mavens on the board will be glad to check them out for you.
Do you have an extra amp or reciever just to drive the subwoofer, or are you trying to run subwoofer, woofer, mid, (if any) and tweeter off one single stereo amp?
If you don't have an extra amp, then as recommended earlier, these sub amps/crossovers definitely seem to be the way to go. the amounts of money you would have to lay out to buy passive components would cost more-why pay more for passive when active crossovers are so much better?
Here are some examples. Note the prices are reasonable:
http://www.partsexpress.com/webpage.cfm?&DID=7&WebPage_ID=3
www.madisound.com Click "catalog" on right, then "Keiga subwoofer amps".
www.bkelec.com Click "Modules and Hybrids".
As to what is cheaper to Reunion Island, I cannot say. Perhaps a quick look at some French speaker mail order houses?
http://www.t-linespeakers.org/tech/filters/passiveHLxo.html
These are useful if you have an amp just to run the subwoofer. They are placed before the subwoofer amp. I haven't tried one, but if this is the way you want to go, try listing the values that you plan to use and the electronics mavens on the board will be glad to check them out for you.
Do you have an extra amp or reciever just to drive the subwoofer, or are you trying to run subwoofer, woofer, mid, (if any) and tweeter off one single stereo amp?
If you don't have an extra amp, then as recommended earlier, these sub amps/crossovers definitely seem to be the way to go. the amounts of money you would have to lay out to buy passive components would cost more-why pay more for passive when active crossovers are so much better?
Here are some examples. Note the prices are reasonable:
http://www.partsexpress.com/webpage.cfm?&DID=7&WebPage_ID=3
www.madisound.com Click "catalog" on right, then "Keiga subwoofer amps".
www.bkelec.com Click "Modules and Hybrids".
As to what is cheaper to Reunion Island, I cannot say. Perhaps a quick look at some French speaker mail order houses?
Here are some cheap practical solutions from the folks over at Parts Express
Inline Passive Crossover @ 100Hz Low Pass and 80Hz Low Pass. Both come in 4 and 8 Ohm versions @ 12dB per octave roll off. ~$16 ea.
Line Level Passive Crossovers @ 100Hz Low Pass and @ 70Hz Low Pass. These are 12dB per octave roll off, but you get two for ~$26...so if your feeding the sub off of one amplifier channel (LFE output) you can daisy chain them and get 24dB roll off.
If your just integrating these with your mains the first ones would be more practical....the 80Hz low pass would make them just fill in the bass demand and not interfere with the midrange as much.
Inline Passive Crossover @ 100Hz Low Pass and 80Hz Low Pass. Both come in 4 and 8 Ohm versions @ 12dB per octave roll off. ~$16 ea.
Line Level Passive Crossovers @ 100Hz Low Pass and @ 70Hz Low Pass. These are 12dB per octave roll off, but you get two for ~$26...so if your feeding the sub off of one amplifier channel (LFE output) you can daisy chain them and get 24dB roll off.
If your just integrating these with your mains the first ones would be more practical....the 80Hz low pass would make them just fill in the bass demand and not interfere with the midrange as much.
Passive line-level filter questions
I'm looking at the passive line-level approach to filtering subwoofers, specifically I'm looking for 24dB/octave (daisychain 2 x 12dB/octave) and I have some questions:
1. Does it require a preamplifier with two outputs?
2. Is some gain lost and do you need power amplifiers with gain controls to adjust the relative sound levels?
3. If you're using one subwoofer in mono, do you need a buffer stage before the filter to avoid messing up separation on the full-range speaker input?
4. Aren't the filter components dependent on the input impedance of the power amp and so vary for each application?
Can anyone help?
Steve
I'm looking at the passive line-level approach to filtering subwoofers, specifically I'm looking for 24dB/octave (daisychain 2 x 12dB/octave) and I have some questions:
1. Does it require a preamplifier with two outputs?
2. Is some gain lost and do you need power amplifiers with gain controls to adjust the relative sound levels?
3. If you're using one subwoofer in mono, do you need a buffer stage before the filter to avoid messing up separation on the full-range speaker input?
4. Aren't the filter components dependent on the input impedance of the power amp and so vary for each application?
Can anyone help?
Steve
moi said:
Moi:
Having trouble following your setup.
A) Are you powering all this from ONE A/V surround sound receiver? If so, please give details as to make, model, and most important, how many channels.
B) I realize that English is not the basic language on Reunion Island, but I am having difficulty understanding such things as:
"1denon 2*70 front speakers dynamic"
"1 toshiba 2*50 rear speakers"
"3 jamo rear speakers 40w each"
I don't know if that means you have 7 rear speakers or five.
C) This is important. Mny A/V receivers have a jack at the back which says "Subwoofer OUT". However, that jack is just a low-level signal, like a tape output. It cannot power anything. It is designed to go to an amplifier that actually powers the subwoofer.
Most of those "Subwoofer OUT" jacks have a high cutoff of 80 Hz, (cuts off the frequencies above 80 Hz). So if you have an old, spare receiver hanging around, you can just run a cable from the "Subwoofer OUT" jack to the "CD in" jack or "Tape in" or your spare receiver, and you have a subwoofer up and running. No crossover necessary.
Does your A/V receiver hava an actual powered output for the subwoofer, or merely a jack to send the signal?
Re: Passive line-level filter questions
Steve:
I haven't used the Passive Line Level crossovers, but I will take a stab at your question-others please correct me if I am wrong.
I don't believe that the impedance of the power amp needs to be known as long as the power amp impedance 10 times or more the value of the R in your crossover circuit.
In my little experience building amps, I came across the "Ten Percent Rule" which says that an output stage of a preceding stage does not "bog down" the input of the following stage as long as the input impedance of the last stage is more than 10 times the preceding stage's output impedance.
If stage A has an output impedance of 1K ohm and stage B has an input impedance of 10K ohm, you should have no problems. If stage A has an output impedance of 5K ohms, and stage B has an input impedance of 10K ohms, then you do have problems.
Most solid state amps have an input impedance of 10K ohms or more, usually above 50K. I do not know about tube amps.
Without having practical experience with these crossovers, I would suggest that as long as the R in the crossover circuit is 1K ohms or less, you should not have anything to worry about in solid state amps or any amp with an input impedance of 10K or above.
I would even speculate that if you are going to daisy-chain several filters, if the total R of all the filters added together is 10 percent or less of the power amp's input impedance, (which we can safely assume to 10K or above in solid state amps), then you might be able to eliminate the insertion loss in higher value, (above 12 dB), filters that Peter Rettweiler referred to in that link.
http://www.t-linespeakers.org/tech/filters/passiveHLxo.html
However, the last assertion is complete speculation on my part. Just a guess.
7V said:
Steve:
I haven't used the Passive Line Level crossovers, but I will take a stab at your question-others please correct me if I am wrong.
I don't believe that the impedance of the power amp needs to be known as long as the power amp impedance 10 times or more the value of the R in your crossover circuit.
In my little experience building amps, I came across the "Ten Percent Rule" which says that an output stage of a preceding stage does not "bog down" the input of the following stage as long as the input impedance of the last stage is more than 10 times the preceding stage's output impedance.
If stage A has an output impedance of 1K ohm and stage B has an input impedance of 10K ohm, you should have no problems. If stage A has an output impedance of 5K ohms, and stage B has an input impedance of 10K ohms, then you do have problems.
Most solid state amps have an input impedance of 10K ohms or more, usually above 50K. I do not know about tube amps.
Without having practical experience with these crossovers, I would suggest that as long as the R in the crossover circuit is 1K ohms or less, you should not have anything to worry about in solid state amps or any amp with an input impedance of 10K or above.
I would even speculate that if you are going to daisy-chain several filters, if the total R of all the filters added together is 10 percent or less of the power amp's input impedance, (which we can safely assume to 10K or above in solid state amps), then you might be able to eliminate the insertion loss in higher value, (above 12 dB), filters that Peter Rettweiler referred to in that link.
http://www.t-linespeakers.org/tech/filters/passiveHLxo.html
However, the last assertion is complete speculation on my part. Just a guess.
all right
my dvd player(sony 735 dolby digital/dts) has
1out for the front speaker- to the denon ampli -to the "dynamic speaker" front speakers
1 out for the rear speakers- to the toshiba ampli -to the b&w rear speakers
- to the 3 jamo speakers
1out for the centre speaker-to the samsung ampli(left channel)- to the altai centre speaker
1 out for the sub-to the samsung ampli(right channel)-to the sub
hard to tune but whaooouu the sound is here and like you want
as all the speakers are 3ways (exept the 3 jamo) i'm looking for a very low filter for the sub
i think only 20-80 hz tunable
bye
my dvd player(sony 735 dolby digital/dts) has
1out for the front speaker- to the denon ampli -to the "dynamic speaker" front speakers
1 out for the rear speakers- to the toshiba ampli -to the b&w rear speakers
- to the 3 jamo speakers
1out for the centre speaker-to the samsung ampli(left channel)- to the altai centre speaker
1 out for the sub-to the samsung ampli(right channel)-to the sub
hard to tune but whaooouu the sound is here and like you want
as all the speakers are 3ways (exept the 3 jamo) i'm looking for a very low filter for the sub
i think only 20-80 hz tunable
bye
OK, then I get it. 
You have both a dedicated amp and filter. The sub filter is most likely incorporated in your receivers cirquits, probably in the digital domain. The receivers often perform "bass management" as well, applying high pass filters on the channels you select not capable of very deep bass and sending these signal to the sub.
My advice: Hook it all up as per the receiver manual and go for it.
You have both a dedicated amp and filter. The sub filter is most likely incorporated in your receivers cirquits, probably in the digital domain. The receivers often perform "bass management" as well, applying high pass filters on the channels you select not capable of very deep bass and sending these signal to the sub.
My advice: Hook it all up as per the receiver manual and go for it.
moi said:i'm looking for a very low filter for the sub
i think only 20-80 hz tunable
bye
I assume that 20-80 Hz tunable filter is on the Samsung amp.
I am a lttle suspicious what that filter might be. Few subs can actually go down to 20 Hz, let alone play well in an area below 20 Hz and need a filter to crossover to another speaker that plays from 20 Hz on up. If the filter on your amp is tunable from 20 to 80 Hz, I am thinking that it probably is a filter that cuts off the output beneath the stated frequency, not above it. In other words, if you set that filter to 50 Hz, it will cut off the frequencies underneath 50 Hz and leave the 60 Hz, 80 Hz, 100 Hz and above alone.
Such a filter would be useful as a "rumble filter" for turntables, (yes, some of us still use them, LOL,
) or in case you want to use the Samsung amp to your main speakers, and have a subwoofer with it's own built in amp and adjustable crossover meet your main speakers at whatever frequency between 20 Hz and 80 Hz that you choose.Good grief, if that is true, then if your Sony dvd player has a jack for the subwoofer that cuts off frequencies above 80 Hz, and your Samsung amp has a filter that cuts off frequencies below 80 Hz, then you are getting no output from the subwoofer.
No wonder you are having problems!
Two suggestions.
A) Can you please consult your Samsung manual and tell us if that 20-80 Hz tunable filter cuts off frequencies above or below the selected frequency?
B) Tell us the model of the Samsung amp?
If it turns out that I am wrong and the amp does indeed cut frequencies beneath the selected frequency, there are still options we can do. But first, I want to get this filter matter straightened out.
Re: Passive line-level filter questions
let me get this straight....
sony 735 feeds 3 amps. 1 denon amp, 1 toshiba amp and 1 samsung amp. the denon amp feeds a "dynamic speaker" the toshiba amp feeds 5 sepakers 2 B&W and 3 Jamo (I dont know hwo this is connected) and the samsung amp feeds a center speaker and you have a spare amp channel for the sub. RIGHT????
U need 2 outputs a Y connector on the pre out of your pre amp. gain lost is minimalif at all. but all youneed is one amp with a gain control to set levels. the othr amp is the reference level. u cannot use passive in mono. dont worry about impedances in teh BJT/FET domain. tubes are another matter but then if you are a SE affocianado you wont be doing this.
if you are going to use teh samsung amp and the sub out from the vd player you are stuck with a range of 20-80Hz. however there is one way.
you have 3 2 channel amps right? that makes 6 channels of power. if you can get a 4th 2 channel amp you could take the output of the 735 split it with a Y connector and then use 2 amps one amp for the B&W and the second for the subs. again remember with pasive XO I do NOT advise in mono subs. you cannot sum channels.
moi said:
let me get this straight....
sony 735 feeds 3 amps. 1 denon amp, 1 toshiba amp and 1 samsung amp. the denon amp feeds a "dynamic speaker" the toshiba amp feeds 5 sepakers 2 B&W and 3 Jamo (I dont know hwo this is connected) and the samsung amp feeds a center speaker and you have a spare amp channel for the sub. RIGHT????
7V said:
U need 2 outputs a Y connector on the pre out of your pre amp. gain lost is minimalif at all. but all youneed is one amp with a gain control to set levels. the othr amp is the reference level. u cannot use passive in mono. dont worry about impedances in teh BJT/FET domain. tubes are another matter but then if you are a SE affocianado you wont be doing this.
moi said:my dvd player(sony 735 dolby digital/dts) has
1out for the front speaker- to the denon ampli -to the "dynamic speaker" front speakers
1 out for the rear speakers- to the toshiba ampli -to the b&w rear speakers- to the 3 jamo speakers
1out for the centre speaker-to the samsung ampli(left channel)- to the altai centre speaker
1 out for the sub-to the samsung ampli(right channel)-to the sub
hard to tune but whaooouu the sound is here and like you want
as all the speakers are 3ways (exept the 3 jamo) i'm looking for a very low filter for the sub
i think only 20-80 hz tunable
bye
if you are going to use teh samsung amp and the sub out from the vd player you are stuck with a range of 20-80Hz. however there is one way.
you have 3 2 channel amps right? that makes 6 channels of power. if you can get a 4th 2 channel amp you could take the output of the 735 split it with a Y connector and then use 2 amps one amp for the B&W and the second for the subs. again remember with pasive XO I do NOT advise in mono subs. you cannot sum channels.
now i get it after reading all the responses that came after i responded......
you want a summing circuit for the 2nd channel of teh samsung amp.....so yo can use 1 sub.....
well these ar quite simple. i dont know where to find one off hand but all yo have to do is use a summing opamp. what really happens is that one channel is inverted and then both channels are summed. you can use 2 opamps to do this too. input one is the -ve of opamp 1 and input 2 is +ve of opamp 2. this inverts the signal. and then you use a 3rd opamp to sum the channels.
you want a summing circuit for the 2nd channel of teh samsung amp.....so yo can use 1 sub.....
well these ar quite simple. i dont know where to find one off hand but all yo have to do is use a summing opamp. what really happens is that one channel is inverted and then both channels are summed. you can use 2 opamps to do this too. input one is the -ve of opamp 1 and input 2 is +ve of opamp 2. this inverts the signal. and then you use a 3rd opamp to sum the channels.
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