Zen Mod said:
Oh, sorry Zen, I misunderstood. You were just calculating the corner frequency and you are of course correct.
In case anyone doesn't know what we're talking about, changing the load impedance will change the shape or Q of the rolloff but not the corner frequency of the filter. The pic shows two 2nd order lowpass crossovers feeding a resistor (not a real driver.) The only difference is the resistor is twice as big in the blue curve.
Attachments
Changing driver impedance will change the corner frequency of first order networks. As the order of the networks goes up the driver has less and less effect on corner frequency.
There are many programs to simulate drivers and crossovers, I don't know of any good free ones (doesn't mean they don't exist). I am lucky enough to have a friend who owns both Leap and MLSSA.
I am also reluctant to tell anyone that the problem is too complicated to tackle without those excellent tools. Determination and segmented aproaches will get you a large part of the way there.
The LT spice simulator will do a good job and even better if driver electrical parameters are included in the model. Like I said before the simulator knows nothing about acoustic properties of drivers or the box they're mounted in. In spite of this, the electronic model is accurate and will display the applied driver voltage.
If you need to go further, a number of papers exist on the internet explaining how to add mechanical models to the spice simulator, these get very complex and given sufficient understanding can end up modeling acoustic output, cone displacement etc.
There are many programs to simulate drivers and crossovers, I don't know of any good free ones (doesn't mean they don't exist). I am lucky enough to have a friend who owns both Leap and MLSSA.
I am also reluctant to tell anyone that the problem is too complicated to tackle without those excellent tools. Determination and segmented aproaches will get you a large part of the way there.
The LT spice simulator will do a good job and even better if driver electrical parameters are included in the model. Like I said before the simulator knows nothing about acoustic properties of drivers or the box they're mounted in. In spite of this, the electronic model is accurate and will display the applied driver voltage.
If you need to go further, a number of papers exist on the internet explaining how to add mechanical models to the spice simulator, these get very complex and given sufficient understanding can end up modeling acoustic output, cone displacement etc.
Speaker Workshop is freeware and very powerful. It's got a bit of a learning curve though.
http://www.audua.com/
Test and Measure
Driver Impedance
Passive Components
Transfer Function
Driver Acoustic Response
Harmonic Distortion
Design
Enclosures
Stock Crossovers
Custom Crossovers
Impedance Compensation Circuits
Analytical Tools
FFT
Inverse FFT
Scaling
Splicing
Filtering
Charting
Crossover Optimization
http://www.audua.com/
Test and Measure
Driver Impedance
Passive Components
Transfer Function
Driver Acoustic Response
Harmonic Distortion
Design
Enclosures
Stock Crossovers
Custom Crossovers
Impedance Compensation Circuits
Analytical Tools
FFT
Inverse FFT
Scaling
Splicing
Filtering
Charting
Crossover Optimization
For just doing crossovers, it's hard to beat Jeff Bagby's free Passive Crossover Designer for Excel. Dead simple to use and it will import driver files.
http://www.pvconsultants.com/audio/crossover/pcd.htm
http://www.pvconsultants.com/audio/crossover/pcd.htm
Though many "complete" speakers sound very good, getting the whole combination function really well is not easy.
I've tried many passive crossovers in the past. Designed many that sounded much better than the original.
Invested a lot of money in expensive caps and coils for my own speakers, discovered that only a few drivers (mostly costly ones) can reveal the better quality of them (for instance a KP-SN (tinfoil) cap in comparison to a MKP cap (MUCH cheaper though still a very fine quality).
Haveing had the opportunity to work with hundreds of factory made loudspeakers and equipment of very high quality working as an engineer for a high-end audio shop (doing custom mods etc.) I don't understand that bi-amping is not getting a lot more popular in the DIY realm.
I was GLAD they invented a very fine sounding AND affordable type of amplifier called the "class T" amp (actually a "class D" but finally one that sounds good........, no great.........., no extraordinary!).
This amp produces sound in a way that I've never heard before, many expensive amps can do a lot of things better, but no amp has ever given me so much possibilities and listening enjoyment! It produces sound in a 3D manner that no amp in this pricerange EVER did! It's simply lightening fast and "multi-megapixel" sounding....
Why I'm posting this is that filtering on the inputs of a power amp would always have my recommendation, the components needed can be kept small (and affordable) and will never have to work even near their limits, improveing sound quality.
I would say:
Use one of those:http://www.marchandelec.com/xm46.html
And a nice pile of amplifiers, each driver haveing their own filtered channel.
Amps can be found here:
http://www.41hz.com
http://www.audiodigit.com
Reviews:
http://www.tnt-audio.com
Now some like cake and some like pie, so I'm merely posting my own preference I've developed in the past 25 years, no offense to anyone else's preferences....
My current system cost me just a few hundred bucks and amuses the hell out of me....
I find it even strange myself, always haveing had a preference for discretely built amps, old equipment (well worn-in...).
Still use my old (50's) quad esl-57 panels ("slightly" modified them though......
) , in a way nothing can beat them (yet)....
I've tried many passive crossovers in the past. Designed many that sounded much better than the original.
Invested a lot of money in expensive caps and coils for my own speakers, discovered that only a few drivers (mostly costly ones) can reveal the better quality of them (for instance a KP-SN (tinfoil) cap in comparison to a MKP cap (MUCH cheaper though still a very fine quality).
Haveing had the opportunity to work with hundreds of factory made loudspeakers and equipment of very high quality working as an engineer for a high-end audio shop (doing custom mods etc.) I don't understand that bi-amping is not getting a lot more popular in the DIY realm.
I was GLAD they invented a very fine sounding AND affordable type of amplifier called the "class T" amp (actually a "class D" but finally one that sounds good........, no great.........., no extraordinary!).
This amp produces sound in a way that I've never heard before, many expensive amps can do a lot of things better, but no amp has ever given me so much possibilities and listening enjoyment! It produces sound in a 3D manner that no amp in this pricerange EVER did! It's simply lightening fast and "multi-megapixel" sounding....
Why I'm posting this is that filtering on the inputs of a power amp would always have my recommendation, the components needed can be kept small (and affordable) and will never have to work even near their limits, improveing sound quality.
I would say:
Use one of those:http://www.marchandelec.com/xm46.html
And a nice pile of amplifiers, each driver haveing their own filtered channel.
Amps can be found here:
http://www.41hz.com
http://www.audiodigit.com
Reviews:
http://www.tnt-audio.com
Now some like cake and some like pie, so I'm merely posting my own preference I've developed in the past 25 years, no offense to anyone else's preferences....
My current system cost me just a few hundred bucks and amuses the hell out of me....
I find it even strange myself, always haveing had a preference for discretely built amps, old equipment (well worn-in...).
Still use my old (50's) quad esl-57 panels ("slightly" modified them though......
) , in a way nothing can beat them (yet)....We agree, its a complex thing, making good sound, and we may end up with something very "simple"
I remember reading about TroelsGravesens newest speaker....
First filter measured fine but sounded awfull... but he didnt give up on drivers as many would have.... instead he made a different filter wich measured alike.... but sounded much better
I remember reading about TroelsGravesens newest speaker....
First filter measured fine but sounded awfull... but he didnt give up on drivers as many would have.... instead he made a different filter wich measured alike.... but sounded much better
Willitwork said:
I nominate v-bro for this year's Stating Of The Obvious Award
Sorry man, I just couldn't resist
Many times good sound can be found in the obvious....
I didn't make lots of line level filters yet, but made lots of those L/C filters. And they'll work fine, just like a huge concrete dam stopping an avalange, I'd rather stop the snowball at the top of the mountain....
The dam would seem more simple than it is, believe me I've built a lot of loudspeakers like Troels gravesens design, very typical european designing style. The drivers that are used are very common and easy to get by in my country, and so is self-adhesive bitumen
.I have for example made all the pre-designed vifa loudspeakers from the intertechnik (distributor) design book, modified at least 50 pair of B&W dm-602 loudspeakers, going even as far as recone-ing the tweeter with a soft-dome (vifa ht-275 dome) and modifying the whole filter top to bottom, the endresult is a loudspeaker sounding 4 times the price (costing only 100 euro's for the mod.) They messed up on some values in the "newer" (the one with the nautilus backloaded tweet...or better known as the one with the silver dome instead of gold dome) dm-602 filter making it sound "louder".....And designed, built and modded many more.......
Bottom line is that I often felt not entirely satisfied (feel the urge to keep switching to different values/qualities) about the result. The large components seem to be so dependent on quality and as many aproaches can lead to similarly good or bad results I always felt it as a compromise.
Amps are way better off driving resistive loads only.
v-bro said:
Many times good sound can be found in the obvious....
I didn't make lots of line level filters yet, but made lots of those L/C filters. And they'll work fine, just like a huge concrete dam stopping an avalange, I'd rather stop the snowball at the top of the mountain....
The dam would seem more simple than it is, believe me I've built a lot of loudspeakers like Troels gravesens design, very typical european designing style. The drivers that are used are very common and easy to get by in my country, and so is self-adhesive bitumen
I have for example made all the pre-designed vifa loudspeakers from the intertechnik (distributor) design book, modified at least 50 pair of B&W dm-602 loudspeakers, going even as far as recone-ing the tweeter with a soft-dome (vifa ht-275 dome) and modifying the whole filter top to bottom, the endresult is a loudspeaker sounding 4 times the price (costing only 100 euro's for the mod.) They messed up on some values in the "newer" (the one with the nautilus backloaded tweet...or better known as the one with the silver dome instead of gold dome) dm-602 filter making it sound "louder".....And designed, built and modded many more.......
Bottom line is that I often felt not entirely satisfied (feel the urge to keep switching to different values/qualities) about the result. The large components seem to be so dependent on quality and as many aproaches can lead to similarly good or bad results I always felt it as a compromise.
Amps are way better off driving resistive loads only.
Ah, but I had no intention of implying any shortcomings on your part.
I have built a few Troels designs myself, fortunately in Canada Solen carries most of the drivers he uses (sometimes with different model numbers though). They also carry bitumen pads (called tar felt here) but unfortunately those are quite expensive here so most people use roofing felt instead, what a mess
Now, if only Troels would do a design using HiVi or Silver Flute drivers, I'd be in Heaven
v-bro said:
I intend to but first I'm trying to resolve a driver supply issue. Unfortunately, it appears that Hi-Vi drivers are not widely distributed in Europe , maybe because of patent issues. And when they are available in Europe, Hi-Vi drivers appear to be much more expensive than they are here and I'm not sure Troels would be interested in designing a project that would cause sourcing problems to European builders and could only qualify as "low-cost" to North American DIY'ers.
But even if this situation lasts I'll try my luck with him anyway, after all European audiophiles do buy commercial speakers with those drivers (Totem, for example) so there should be some interest
Low cost is only a matter of time, before you know the smoke comes from the pipes of a bigger factory Or some european subcontractor.....
Anyway, how's the progress on the delivery of the drivers GCM?
What's your amp like?
To Dave (planet10): on that t-linespeakers.org site is very helpful info!
Would love to know more about how to make a better (the best
) filter like this:http://www.t-linespeakers.org/tech/filters/passiveHLxo.html
Found little more on the net than the raw basics of it......
Applying the raw basics has nevertheless lead to pretty satisfying results allready...
Or some european subcontractor.....Anyway, how's the progress on the delivery of the drivers GCM?
What's your amp like?
To Dave (planet10): on that t-linespeakers.org site is very helpful info!
Would love to know more about how to make a better (the best
) filter like this:http://www.t-linespeakers.org/tech/filters/passiveHLxo.htmlFound little more on the net than the raw basics of it......
Applying the raw basics has nevertheless lead to pretty satisfying results allready...
v-bro said:Would love to know more about how to make a better (the best
Found little more on the net than the raw basics of it......[/B]
It is a pretty basic concept... the only icing is to actually build them into the amps... in the case of the hi-pass this means just shrinking a coupling cap (for a 1st order filter). If your amp is 2 stages, you can make a 2nd order filter without the droop of a regular passive 2nd order, just shrink 2 coupling caps.
The next thing that could be explored are PLL LC filters -- we need to source some suitable large value indictors thou.
Like the Marchand XM46 http://www.marchandelec.com/xm46.html
dave
No Drivers yet... but I was told that the woofer is 6ohm...
Still waiting for the package and I really know very little about what it will bring.
A friend sent me the schematic via email and said the rest would arrive next(this) week.
As for amplifiers, I run two Bel Canto evo 200.2 amps bridged as monoblocks... although, I have been reading the class D section.......
Once again, Thanks to all for your help and insight... GCM
Still waiting for the package and I really know very little about what it will bring.
A friend sent me the schematic via email and said the rest would arrive next(this) week.
As for amplifiers, I run two Bel Canto evo 200.2 amps bridged as monoblocks... although, I have been reading the class D section.......
Once again, Thanks to all for your help and insight... GCM
v-bro said:Low cost is only a matter of time, before you know the smoke comes from the pipes of a bigger factory
What I suspect is happening is that due to the fact that some Hi-Vi drivers tend to replicate well-known European speakers (Dynaudio and Focal mainly) the company may be hesitant to distribute its drivers in Europe for the moment, fearing these maufacturers may invoke patent infringement. But with Dynaudio and Focal both pulling out of the OEM market this situation will likely resolve itself in the near future.
Surprise surprise, what are those freaking nice amps goin' to drive? Your amp uses the same chipbrand (Tripath) as my amp, and I love the sonic character of those chips!
Thanks Dave, presently my input caps (that is the "coupling cap" right?) are 1.2uF... Should I shrink those?
If I don't shrink them, do I have to low Q?
Does PLL LC filter stand for "passive line level" LC filter? Is there some link to more info on this you could provide? I can only find links to broadcasting purpose filters, nothing specific to audio purposes
LC filters have less insertion loss right? Marchand seems to prefer this type of filter, are the audio qualities of LC better than RC or is it only a matter of "loss"?
Thanks again...
To Willitwork: Morel also produces drivers with the Dynaudio design, they are produced in Israel (company started with former Dynaudio staff). They are however distributed in Europe...
Thanks Dave, presently my input caps (that is the "coupling cap" right?) are 1.2uF... Should I shrink those?
If I don't shrink them, do I have to low Q?
Does PLL LC filter stand for "passive line level" LC filter? Is there some link to more info on this you could provide? I can only find links to broadcasting purpose filters, nothing specific to audio purposes
LC filters have less insertion loss right? Marchand seems to prefer this type of filter, are the audio qualities of LC better than RC or is it only a matter of "loss"?
Thanks again...
To Willitwork: Morel also produces drivers with the Dynaudio design, they are produced in Israel (company started with former Dynaudio staff). They are however distributed in Europe...
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