Hi,
I want to convert the attached HP crossover of my Infinity RS-1B speaker system from passive to active. My knowledge concerning crossovers is limited to very basic theory, so I need help and examples of a converted version. Any help is greatly appreciated.
Thanks in advance.
I want to convert the attached HP crossover of my Infinity RS-1B speaker system from passive to active. My knowledge concerning crossovers is limited to very basic theory, so I need help and examples of a converted version. Any help is greatly appreciated.
Thanks in advance.
Attachments
I want to convert the attached HP crossover of my Infinity RS-1B
You haven't given us much to go on.
How basic is your knowledge?
Do you want a completely active crossover with four sets of stereo amplifiers?
Do you want to use commercial active crossovers or design your own? If yes to the second part, have you done any active filter design?
How much equipment for measurement do you have for measuring the acoustic and electrical frequency response.
This is a hell of a big project. Even with my knowledge and equipment it could take months depending on the amount of it that you actual what to build from scratch.
Fred
You haven't given us much to go on.
How basic is your knowledge?
Do you want a completely active crossover with four sets of stereo amplifiers?
Do you want to use commercial active crossovers or design your own? If yes to the second part, have you done any active filter design?
How much equipment for measurement do you have for measuring the acoustic and electrical frequency response.
This is a hell of a big project. Even with my knowledge and equipment it could take months depending on the amount of it that you actual what to build from scratch.
Fred
This is a hell of a big project.
I was looking at that thread and didn't know what to say. I would probably start from looking at the specs of your speakers and find out the crossover freq.
Next thing I would use forum's search engine and find out all the available info on active crossovers. There is quite a lot out there with good examples. If you decide on particular approach, let us know.
I was looking at that thread and didn't know what to say. I would probably start from looking at the specs of your speakers and find out the crossover freq.
Next thing I would use forum's search engine and find out all the available info on active crossovers. There is quite a lot out there with good examples. If you decide on particular approach, let us know.
Re: This is a hell of a big project.
If you really want to mutate this I'd start one step at a time and work my way up. 1st step would be to just biamp. Lose the low pass on the upper midrange and the entire XO on the lower mid. Everything is 2nd order. You'd want to stick to that, and the same XO frequencies unless you have at least some of the kit Fred mentions.
And this question needs asking -- where are the woofers? Already active.
My personal take would be that you'd probably be way ahead to just start from scratch. This sucker is a 5-way with a back-fill tweeter -- way too many crossoover points to get things seemless.
dave
If you really want to mutate this I'd start one step at a time and work my way up. 1st step would be to just biamp. Lose the low pass on the upper midrange and the entire XO on the lower mid. Everything is 2nd order. You'd want to stick to that, and the same XO frequencies unless you have at least some of the kit Fred mentions.
And this question needs asking -- where are the woofers? Already active.
My personal take would be that you'd probably be way ahead to just start from scratch. This sucker is a 5-way with a back-fill tweeter -- way too many crossoover points to get things seemless.
dave
I've decided to do some research on this topic
Great! Exactly the course to take!
And what do we have for our winner Johnny?
Here are some links and feel free to ask further questions. I did not mean to scare you off but just to place you at the proper destination for the start of your journey.
http://www.termpro.com/articles/xover.html
http://www.crossovers.com/links_to_other.html
http://www.tubecad.com/articles_2001/Active_Crossovers_and_Filters/index.html
http://www.tubecad.com/articles_2001/Active_Crossovers_and_Filters/index.html
Fred
P.S. Other suggestions and info on the RS-1s that might help, anyone?
"Please don't leave me in suspense"
No.... leave him in suspense
Then maybehe might run a search engine and find
http://www.bobbyshred.com/infinity.html
Great! Exactly the course to take!And what do we have for our winner Johnny?
Here are some links and feel free to ask further questions. I did not mean to scare you off but just to place you at the proper destination for the start of your journey.
http://www.termpro.com/articles/xover.html
http://www.crossovers.com/links_to_other.html
http://www.tubecad.com/articles_2001/Active_Crossovers_and_Filters/index.html
http://www.tubecad.com/articles_2001/Active_Crossovers_and_Filters/index.html
Fred
P.S. Other suggestions and info on the RS-1s that might help, anyone?
"Please don't leave me in suspense"
No.... leave him in suspense
Then maybehe might run a search engine and find
http://www.bobbyshred.com/infinity.html
Hi Fred,
Will take a look at links provided.
For Dave and others intersted in the complete
schematic of the RS-1B which has an active controller for the woofers, the PDF sheet can be watched or downloaded here:
http://www.cae-cd.com
Franklin
Will take a look at links provided.
For Dave and others intersted in the complete
schematic of the RS-1B which has an active controller for the woofers, the PDF sheet can be watched or downloaded here:
http://www.cae-cd.com
Franklin
Here are two links on crossovers that I find useful:
http://www.diyaudio.com/forums/show...8&perpage=15&highlight=crossover&pagenumber=2
http://www.diyaudio.com/forums/showthread.php?s=&threadid=4209&highlight=crossover
http://www.diyaudio.com/forums/show...8&perpage=15&highlight=crossover&pagenumber=2
http://www.diyaudio.com/forums/showthread.php?s=&threadid=4209&highlight=crossover
hi,
the short answer is : don't do it... it's impossible - only a few on this earth really know how to design loudspeakers.
but!!!!!!!!! if you like to fool arround and you are having fun working with speakers : do it.
but if you think you can save a few bucks or make a better speaker, it will be a total waste of both time and money.
good luck,
troels
ps if "cost is no object" check out the bigger atc active speakers.
the short answer is : don't do it... it's impossible - only a few on this earth really know how to design loudspeakers.
but!!!!!!!!! if you like to fool arround and you are having fun working with speakers : do it.
but if you think you can save a few bucks or make a better speaker, it will be a total waste of both time and money.
good luck,
troels
ps if "cost is no object" check out the bigger atc active speakers.
Re: I've decided to do some research on this topic
And here is a link to a page of
Active XO Links that Fred missed.
Nice link Fred, it does have an earlier version of speaker in question. It clearly points out that what we actually have is a 3 way with rear firing tweeter, tapered mid & tweeter arrays and an active woofer. Now i'd be even less likely to bother rejigging the speaker, better to use it as inspiration and start fresh.
Fred, all this moderating keeps me busy busy. Thankfully we have you fishing the links up... you ever tried using Sherlock? Makes finding things even easier.
dave
Fred Dieckmann said:
And here is a link to a page of
Active XO Links that Fred missed.
No.... leave him in suspense
Then maybehe might run a search engine and find
http://www.bobbyshred.com/infinity.html
Nice link Fred, it does have an earlier version of speaker in question. It clearly points out that what we actually have is a 3 way with rear firing tweeter, tapered mid & tweeter arrays and an active woofer. Now i'd be even less likely to bother rejigging the speaker, better to use it as inspiration and start fresh.
Fred, all this moderating keeps me busy busy. Thankfully we have you fishing the links up... you ever tried using Sherlock? Makes finding things even easier.
dave
A complete and very informative Infinity webiste can be found here:
http://oellerer.net/infinity_classics/
My idea to try and see if the x-over on the RS-1B which I own, can be improved lies in the fact that the audio signal has to travel trough a lot of capacitors and coils. An active x-over could simplify things and lessen the need for the space needed to place those components in the x-over
housing behind the screens. On the other hand it will take a 5-channel power amp to drive all seperate x-overs.
Franklin
http://oellerer.net/infinity_classics/
My idea to try and see if the x-over on the RS-1B which I own, can be improved lies in the fact that the audio signal has to travel trough a lot of capacitors and coils. An active x-over could simplify things and lessen the need for the space needed to place those components in the x-over
housing behind the screens. On the other hand it will take a 5-channel power amp to drive all seperate x-overs.
Franklin
Franklin,
I've done a passive-to-active conversion on a number of speaker systems. It's not a trivial job, but it can be done. You'd need to make terminal measurements at each of the drivers to generate "target curves" for the electrical response that an active crossover would have to match. Alternately, you could measure the impedance curve of each raw driver and then "construct" the crossover with a simulation program to generate the target curves.
This, of course, is assuming you actually WANT to recreate the original the crossover with an active version. I think it's certainly possible that an active crossover system would allow you to improve upon the original design.
The whole thing could get pretty complicated, but the tools (software programs and measuring systems) are out there to accomplish this project should you decide to proceed.
I agree with some of the other posters. Most of the benefit from going active can be gained by concentrating on just the lower crossover points.
Cheers,
Davey.
I've done a passive-to-active conversion on a number of speaker systems. It's not a trivial job, but it can be done. You'd need to make terminal measurements at each of the drivers to generate "target curves" for the electrical response that an active crossover would have to match. Alternately, you could measure the impedance curve of each raw driver and then "construct" the crossover with a simulation program to generate the target curves.
This, of course, is assuming you actually WANT to recreate the original the crossover with an active version. I think it's certainly possible that an active crossover system would allow you to improve upon the original design.
The whole thing could get pretty complicated, but the tools (software programs and measuring systems) are out there to accomplish this project should you decide to proceed.
I agree with some of the other posters. Most of the benefit from going active can be gained by concentrating on just the lower crossover points.
Cheers,
Davey.
Franklin:
First I have to say that I`m really a fan of active speakers and I hardly do anything passive anymore.
Although said this, I wouldn`t change this crossover to active because I don`t see much benefits doing so in this particular case.
The reason is that this drivers are isoplanar drivers (or magnetostatic) and IMO those do not benefit as much as moving coil speakers from an "activation" and the (moving coil) woofers are already driven directly (active) .
The main advantages (besides others) from active driven moving coil speakers over passive is better electrical damping and less "thermal modulation" as I would call it.
Magnetostatic drivers do not benefit from electrical damping because they are completly mechanically damped.
About "thermal modulation":
The voice coil resistance (or better to say impedance which is it`s AC-resistance) of a moving-coil speaker is heat respectively temperature dependend. With changing power input the voice coil heats up and down. And remember: speakers in most cases are very, very low effciency devices - at 100W input and @1% effeciency (which is quite high already) the voice coil dissipates 99W into heat and only the rest into acoustic energy. This is not a trivial disadvantage of moving coil speakers when used with passive x-overs.
Now what has this to do with active versus passive crossovers and in this particular case?
The proper function of a passive crossover is dependend of it`s (constant) termination resistance which is the drivers impedance.
As the voice coil temperature and therefore it`s resistance (impedance) is going to change according the momentary power input from the amplifier the passive crossover do not "see" a constant termination resistance anymore and "thermal modulation" of the crossovers properties (concerning: xover point, slope, phase response, attenuation) happens.
All this do not apply (or almost not) to magnetostatic drivers as they do not have a voice coil in the common sense (I mean mounted in a narrow air gap with bad heat dissipation transfer) and their "air cooled" diaphragms with the conductors are much less sensitive to temperature changes due to changing power consumption thus the mentioned "thermal modulation" is much less an issue.
If You still want to make anything better I would suggest "just" to drive each range with an individual amplifier (multiamping) and leave the passive crossover as it is (of course You have to diconnect the nodes at the x-over input terminal in order to make seperated inputs for the individual ranges).
Not only that You avoid the "hell of a big project" as mentioned already by Fred, I really doubt that You gain much (if at all or making it even worse) by completly changing THIS x-over to active due to the mentioned reasons.
First I have to say that I`m really a fan of active speakers and I hardly do anything passive anymore.
Although said this, I wouldn`t change this crossover to active because I don`t see much benefits doing so in this particular case.
The reason is that this drivers are isoplanar drivers (or magnetostatic) and IMO those do not benefit as much as moving coil speakers from an "activation" and the (moving coil) woofers are already driven directly (active) .
The main advantages (besides others) from active driven moving coil speakers over passive is better electrical damping and less "thermal modulation" as I would call it.
Magnetostatic drivers do not benefit from electrical damping because they are completly mechanically damped.
About "thermal modulation":
The voice coil resistance (or better to say impedance which is it`s AC-resistance) of a moving-coil speaker is heat respectively temperature dependend. With changing power input the voice coil heats up and down. And remember: speakers in most cases are very, very low effciency devices - at 100W input and @1% effeciency (which is quite high already) the voice coil dissipates 99W into heat and only the rest into acoustic energy. This is not a trivial disadvantage of moving coil speakers when used with passive x-overs.
Now what has this to do with active versus passive crossovers and in this particular case?
The proper function of a passive crossover is dependend of it`s (constant) termination resistance which is the drivers impedance.
As the voice coil temperature and therefore it`s resistance (impedance) is going to change according the momentary power input from the amplifier the passive crossover do not "see" a constant termination resistance anymore and "thermal modulation" of the crossovers properties (concerning: xover point, slope, phase response, attenuation) happens.
All this do not apply (or almost not) to magnetostatic drivers as they do not have a voice coil in the common sense (I mean mounted in a narrow air gap with bad heat dissipation transfer) and their "air cooled" diaphragms with the conductors are much less sensitive to temperature changes due to changing power consumption thus the mentioned "thermal modulation" is much less an issue.
If You still want to make anything better I would suggest "just" to drive each range with an individual amplifier (multiamping) and leave the passive crossover as it is (of course You have to diconnect the nodes at the x-over input terminal in order to make seperated inputs for the individual ranges).
Not only that You avoid the "hell of a big project" as mentioned already by Fred, I really doubt that You gain much (if at all or making it even worse) by completly changing THIS x-over to active due to the mentioned reasons.
Why not build new speakers?
Franklin
I have been down your thought road with my two way speakers, and come up with the conclusion that it would be better not to mess with a good commercial design but to take the opportunity of upgrading to something better by building my own and going active at that time.
Why?
By taking out the current passive XO, you are throwing away its value. In your speaker the XO probably cost a fair bit of its purchase price, and so taking it out means that that value is "lost", until you put it back in of course.
Assuming that you want a better sounding speaker, you can experience lots more fun by building your own more simple design (eg two way) and going active, putting in some high class drivers and using a good cabinet design to give you an upgrade from your Infinities.
You can then sell your current speakers, use them as rear speakers or in another room.
Having said all this, it sounds like the Inifinities would have a fairly unique sound, that you may particularly like, so a standard 2 or 3 way may not be your cup of tea.
Mick
Franklin
I have been down your thought road with my two way speakers, and come up with the conclusion that it would be better not to mess with a good commercial design but to take the opportunity of upgrading to something better by building my own and going active at that time.
Why?
By taking out the current passive XO, you are throwing away its value. In your speaker the XO probably cost a fair bit of its purchase price, and so taking it out means that that value is "lost", until you put it back in of course.
Assuming that you want a better sounding speaker, you can experience lots more fun by building your own more simple design (eg two way) and going active, putting in some high class drivers and using a good cabinet design to give you an upgrade from your Infinities.
You can then sell your current speakers, use them as rear speakers or in another room.
Having said all this, it sounds like the Inifinities would have a fairly unique sound, that you may particularly like, so a standard 2 or 3 way may not be your cup of tea.
Mick
Knowing that Arnie Nudell the designer of the best Infinity speaker systems consciously has chosen for a passive x-over for the screens, who am I to question his choice. On the other hand, knowing that these speakers are 22 year old desings and technology has advanced over the years, my approach is/was to look at what can be improved in this system and if the improvement turns out to be what I expected or even better it's worth the effort.
I have also been thinking of building a clone of the Wisdom Audio Adrenaline which uses a modified B&G RD75 driver with a completely active x-over. Already dropped this idea in the B&G DIY forum, but most builders there are working on different configurations with the B&G drivers. It would be nice to backengineer this system and if there are others here interested in doing so, it would be best to start another thread and share the info I have gathered over several months on this design. As a lover of dipoles I will always have such a system due to my broad listening range of music. I've had Maggies for a couple of years, but they lacked a lot of bass which in classical music is very important.
For those not familiar with the Wisdom Audio Adrenaline I have attached a picture. They currently have other systems in their product range, but the Adrenaline was of of their first outstanding products.
Franklin
I have also been thinking of building a clone of the Wisdom Audio Adrenaline which uses a modified B&G RD75 driver with a completely active x-over. Already dropped this idea in the B&G DIY forum, but most builders there are working on different configurations with the B&G drivers. It would be nice to backengineer this system and if there are others here interested in doing so, it would be best to start another thread and share the info I have gathered over several months on this design. As a lover of dipoles I will always have such a system due to my broad listening range of music. I've had Maggies for a couple of years, but they lacked a lot of bass which in classical music is very important.
For those not familiar with the Wisdom Audio Adrenaline I have attached a picture. They currently have other systems in their product range, but the Adrenaline was of of their first outstanding products.
Franklin
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