Hey Everyone,
I am currently building my first three way speaker system and am basing it on a design from the late fifties. The speakers will use a vintage CTS 15 inch ceramic magnet woofer with an early Trio 8 inch mid/woof and probably a B-G planar transducer for the highs. I have built a few two ways and regularly use military spec hermetically sealed capacitors for my crossovers. They aren't cheap but are very smooth and clean sounding. I want to create the simplest three way crossover possible. I definitely prefer a minimum of components. The 15 will only be used to 500 Hz while the eight will go up to a max of 2500 Hz. Any help with crossover design would be greatly appreciated. Thanks in advance.
--Rlabomb
I am currently building my first three way speaker system and am basing it on a design from the late fifties. The speakers will use a vintage CTS 15 inch ceramic magnet woofer with an early Trio 8 inch mid/woof and probably a B-G planar transducer for the highs. I have built a few two ways and regularly use military spec hermetically sealed capacitors for my crossovers. They aren't cheap but are very smooth and clean sounding. I want to create the simplest three way crossover possible. I definitely prefer a minimum of components. The 15 will only be used to 500 Hz while the eight will go up to a max of 2500 Hz. Any help with crossover design would be greatly appreciated. Thanks in advance.
--Rlabomb
Well, really a 3-way crossover is just two 2-way crossovers.
Here is a place with a 2-way and 3-way crossover designer -
2-Way XO -
http://www.lalena.com/Audio/Calculator/XOver/Help.aspx
3-Way APC XO -
http://www.lalena.com/Audio/Calculator/APCXOver/
Another 2- Way crossover designer -
http://www.apicsllc.com/apics/Misc/filter2.html
to use two 2-way crossovers -
Calculate the low crossover point and this will give you the values for the woofer and the highpass of the mid.
Calculate the high crossover point, and this will give you the low pass for your Mid and the high pass for your tweeter.
Just a few thoughts.
Steve/bluewizard
Here is a place with a 2-way and 3-way crossover designer -
2-Way XO -
http://www.lalena.com/Audio/Calculator/XOver/Help.aspx
3-Way APC XO -
http://www.lalena.com/Audio/Calculator/APCXOver/
Another 2- Way crossover designer -
http://www.apicsllc.com/apics/Misc/filter2.html
to use two 2-way crossovers -
Calculate the low crossover point and this will give you the values for the woofer and the highpass of the mid.
Calculate the high crossover point, and this will give you the low pass for your Mid and the high pass for your tweeter.
Just a few thoughts.
Steve/bluewizard
Hi,
Those calculators are basically completely
wrong and not the simplest way to do it.
If the drivers are not matched for sensitivity L-pads may be needed.
There have been some interesting posts on minimal series 3-way
crossovers, by Andy Graddon I think, but the search function here
is useless and the links to his pages no longer work.
/sreten.
Those calculators are basically completely
wrong and not the simplest way to do it.
If the drivers are not matched for sensitivity L-pads may be needed.
There have been some interesting posts on minimal series 3-way
crossovers, by Andy Graddon I think, but the search function here
is useless and the links to his pages no longer work.
/sreten.Sreten,
with all due respect, and I do respect you; your knowledge and experience are infinite compared to mine.
But...how have you helped?
At least I pointed the guy to some resources to actually get the job done.
You claim -
"Those calculators are basically completely wrong and not the simplest way to do it."
But again...no explanation and no alternate resources. And really...what could be simpler than entering the speaker values and getting the L and C values in return.
One of the links calculates Linkwitz-Riley, Butterworth, and Bessel filters. Am I really to believe that those calculation are utterly and completely wrong?
If they are wrong, then point the person to some that are right.
Again, with all due respect...how have you helped?
Steve/bluewizard
with all due respect, and I do respect you; your knowledge and experience are infinite compared to mine.
But...how have you helped?
At least I pointed the guy to some resources to actually get the job done.
You claim -
"Those calculators are basically completely wrong and not the simplest way to do it."
But again...no explanation and no alternate resources. And really...what could be simpler than entering the speaker values and getting the L and C values in return.
One of the links calculates Linkwitz-Riley, Butterworth, and Bessel filters. Am I really to believe that those calculation are utterly and completely wrong?
If they are wrong, then point the person to some that are right.
Again, with all due respect...how have you helped?
Steve/bluewizard
The 3-way series x-o stuff is no longer on my web site due to the limited amount space given by my isp. Also time for upkeep and update is an issue.
(If anyone want the series x-o pages, feel free to email me, I've still got them somewhere)
If you can post the frequency response curves of the drivers , I can see if a simple 3-way series might work, and maybe give some ideas for some starting point values.
(If anyone want the series x-o pages, feel free to email me, I've still got them somewhere)
If you can post the frequency response curves of the drivers , I can see if a simple 3-way series might work, and maybe give some ideas for some starting point values.
BlueWizard said:
Sreten is correct. these things are "text book" cross-overs, which only work with "text book" drivers.. and I don't think there are many drivers that come close to being that !!
Many some of the Peerless nomex, which are flat as, but most drivers have issues that need to be addressed or avoided.
You CANNOT just take random drivers and apply text book calculations and hope to achieve much more than mediocre, but more likely........ yuck !!!
Thanks AG for the response, and thanks Sreten for not taking offense, or at least, not showing offense. Again, it was said ...with all due respect and a great deal of respect is certainly due.
But, I think we might be up against the $1,000 response to a $100 question.
This person made it clear he wants a basic straight forward 3-way crossover. Since he is using what I assume is an old CTS woofer, he likely doesn't have and can't get the specs on it.
So, his choices are work off of generic values or test the speakers to find the T/S parameters and get a frequency response graph.
Which brings up the next question, does this person have a computer, design- modeling- testing-software, and all necessary gizmos and gadgets (all of which cost money, and take time to learn) to test for the parameters? And how much time and money is he willing to spend to get all these gizmos and gadgets necessary to do detailed testing. The basic Dayton woofer tester (WT3) is only about $100 or so, is he willing to spend that much to get it perfect or more perfect?
I think the first step is to make a determination of resources. Which I admit I didn't do in this case any more than you. Then tailor the response to the person's skill and resource level, though with encouragement to move both skill and resource upward.
If he has the material resources, then he should certainly use them. But if not, I think the response should be tailor to the resources he does have.
You say generic calculation won't produce more than mediocre results. But 'mediocre' relative to what? Mediocre relative the the absolute level of perfection you are striving for, or mediocre relative to common low to mid priced consumer speakers?
I think, as a first step, we need to question the selected crossover points. Did this person select these because he has some knowledge that they are workable with these speakers, or did he pick them because they seemed like cool values.
So, more than anything, I think questioning the crossover points is the first step.
The low crossover seems reasonable at 500hz. Certainly that is well within the working range of the 15" woofer, and likely within the working range of the 8" MidBass. But in a 3-way, the workable frequency span is pretty wide.
The high crossover could be a problem though. First, do we have some assurance that the 8" MidBass is functioning well at 2,500hz? Not just functioning, but functioning well. For most midbass, 2,500hz is pushing pretty close to the upper limit.
Next, the B-G planar transducer, are we sure the 2,500hz crossover points is well within the working range of this tweeter?
At this point it might be nice to remind people that rated or stated frequency response is pretty much meaningless. Just because a spec sheet says 2,000 - 20,000hz doesn't mean the speaker is functionally usable across that range. Likely you would have to have a significantly higher crossover than 2,000hz to safely and effectively use this speaker.
So, we need some answers from the original poster.
First is some assessment of his skill and resources. Exactly how much equipment does he have and how much work is he willing to do to optimize the crossovers for these specific speakers?
Next, we need some assurance, that the given speakers (model numbers would be ideal) can actually functionally operate in the selected range.
Once we determine what crossover can be made, then we can move on to how it is made.
Does that sound like a reasonable approach?
EDITED:
Oops, forgot this link-
Elliot Sound Products - Passive Crossover Network Design
http://sound.westhost.com/lr-passive.htm
A pretty good primer for anyone starting out.
Also, here is a link to a discussion on Crossover design with links to other discussions on crossover design.
http://www.diyaudio.com/forums/showthread.php?s=&threadid=90490&highlight=
Scroll down to post #14 for more links.
Here is another crossover discussion that goes on for several pages -
http://www.diyaudio.com/forums/showthread.php?threadid=88567&highlight=
Steve/bluewizard
But, I think we might be up against the $1,000 response to a $100 question.
This person made it clear he wants a basic straight forward 3-way crossover. Since he is using what I assume is an old CTS woofer, he likely doesn't have and can't get the specs on it.
So, his choices are work off of generic values or test the speakers to find the T/S parameters and get a frequency response graph.
Which brings up the next question, does this person have a computer, design- modeling- testing-software, and all necessary gizmos and gadgets (all of which cost money, and take time to learn) to test for the parameters? And how much time and money is he willing to spend to get all these gizmos and gadgets necessary to do detailed testing. The basic Dayton woofer tester (WT3) is only about $100 or so, is he willing to spend that much to get it perfect or more perfect?
I think the first step is to make a determination of resources. Which I admit I didn't do in this case any more than you. Then tailor the response to the person's skill and resource level, though with encouragement to move both skill and resource upward.
If he has the material resources, then he should certainly use them. But if not, I think the response should be tailor to the resources he does have.
You say generic calculation won't produce more than mediocre results. But 'mediocre' relative to what? Mediocre relative the the absolute level of perfection you are striving for, or mediocre relative to common low to mid priced consumer speakers?
I think, as a first step, we need to question the selected crossover points. Did this person select these because he has some knowledge that they are workable with these speakers, or did he pick them because they seemed like cool values.
So, more than anything, I think questioning the crossover points is the first step.
The low crossover seems reasonable at 500hz. Certainly that is well within the working range of the 15" woofer, and likely within the working range of the 8" MidBass. But in a 3-way, the workable frequency span is pretty wide.
The high crossover could be a problem though. First, do we have some assurance that the 8" MidBass is functioning well at 2,500hz? Not just functioning, but functioning well. For most midbass, 2,500hz is pushing pretty close to the upper limit.
Next, the B-G planar transducer, are we sure the 2,500hz crossover points is well within the working range of this tweeter?
At this point it might be nice to remind people that rated or stated frequency response is pretty much meaningless. Just because a spec sheet says 2,000 - 20,000hz doesn't mean the speaker is functionally usable across that range. Likely you would have to have a significantly higher crossover than 2,000hz to safely and effectively use this speaker.
So, we need some answers from the original poster.
First is some assessment of his skill and resources. Exactly how much equipment does he have and how much work is he willing to do to optimize the crossovers for these specific speakers?
Next, we need some assurance, that the given speakers (model numbers would be ideal) can actually functionally operate in the selected range.
Once we determine what crossover can be made, then we can move on to how it is made.
Does that sound like a reasonable approach?
EDITED:
Oops, forgot this link-
Elliot Sound Products - Passive Crossover Network Design
http://sound.westhost.com/lr-passive.htm
A pretty good primer for anyone starting out.
Also, here is a link to a discussion on Crossover design with links to other discussions on crossover design.
http://www.diyaudio.com/forums/showthread.php?s=&threadid=90490&highlight=
Scroll down to post #14 for more links.
Here is another crossover discussion that goes on for several pages -
http://www.diyaudio.com/forums/showthread.php?threadid=88567&highlight=
Steve/bluewizard
Hi,
$1000 answer for a $100 question ? My first one ?
What seems reasonable to you, might not seem reasonable to me ...
Though the questions that need to be asked are starting .....
How old is the trio 8" ? designed for a tweeter or not perhaps ?
I do find crossover primers incredibly dull and misleading.
Getting the original poster to understand to a degree what is going
on is the only way to get near the simplest 3-way possible that is
also not very likely very wrong.
/sreten.
$1000 answer for a $100 question ? My first one ?
What seems reasonable to you, might not seem reasonable to me ...
Though the questions that need to be asked are starting .....
How old is the trio 8" ? designed for a tweeter or not perhaps ?
I do find crossover primers incredibly dull and misleading.
Getting the original poster to understand to a degree what is going
on is the only way to get near the simplest 3-way possible that is
also not very likely very wrong.
/sreten.
my guess is that the simplest way would be to grab some electrolytics caps and some variable L-pads, use a cap size for protection designed for around 4k on the BG, and a cap on the 8"so it doesn't confuse the bottom end.
L-pads on both to balance them. Maybe put a coil on the woofer to roll it off at its top end.
It is likely that these older style drivers will actually work quite well that way.
Trying to design higher order x-os for drivers with unknown frequency response is a mugs game, and not worth the drama.
Either do the full measurement thing or go 1st order protection and hope !!.
L-pads on both to balance them. Maybe put a coil on the woofer to roll it off at its top end.
It is likely that these older style drivers will actually work quite well that way.
Trying to design higher order x-os for drivers with unknown frequency response is a mugs game, and not worth the drama.
Either do the full measurement thing or go 1st order protection and hope !!.
"I do find crossover primers incredibly dull and misleading" - can we look forward to an interesting and accurate primer from you, or perhaps an example of how you've solved the problems involved in an actual implimentation of a crossover would be more instructive?
The last calculator that BlueWizard linked in post 2 is actually quite useful if you've done an impedance plot. And naturally you need FR plots to choose the xover points.
So Rlabomb needs some method of measuring his drivers - I recommend Synrta for FR plots, and the LIMP module of ARTA for other T/S parameters, both are easy to set up and use
The last calculator that BlueWizard linked in post 2 is actually quite useful if you've done an impedance plot. And naturally you need FR plots to choose the xover points.
So Rlabomb needs some method of measuring his drivers - I recommend Synrta for FR plots, and the LIMP module of ARTA for other T/S parameters, both are easy to set up and use
tipicreeper said:
Chuckle.. I think it is important that "newbies" realise that x-o design is something that requires a bit of learning.
If you want worthwhile sounding speakers, anyway.
Fortunately, older drivers often tended to have reasonably flat response curves, so he MIGHT get lucky, and be able to produce something without all the measurements..maybe, perhaps...
Then again.. he might win the lottery next week !
Well as Tinutus flat out says, and as Andy and Sreten imply -
"Simplicity is not that simple."
No matter how much (or how little) you know, there is always infinitely more knowledge to be learned. But you don't become an astronaut until you learn to fly a plane first. And you don't become a designer of near perfect speakers until you've built a few so-so speakers first.
So again, I think it is necessary to tailor the response to the questioner's skill and resource level. If he needs to know the impedance of the speakers at the crossover frequency, he can simply record test tones onto a CD, and put a resistor in series with the speaker. Then while the tone plays, measure the total applied voltage and the voltage across the resistor and the voltage across the speaker. That should give him enough to determine the impedance with reasonable accuracy. And more importantly it only requires about $30 in parts and equipment (not counting the CD player). That doesn''t require heaps of skill, knowledge, or equipment, and simply needs to be tempered with a dash of common sense.
Again, what we really need is a response from the original poster to give us some idea of his skill and resources, and some idea of the likelihood that his chosen crossovers are correct.
As to will a 'textbook' crossover work, there are plenty of fairly good consumer speakers out there that have basic straight forward 12db crossovers in them, and even a few speaker across quite a range of quality that have a simple single capacitor crossover.
Again, if you are trying to reach a level of perfection, then every little detail must be considered and corrected in the design. But if the person is simply looking for a basic level of function in the crossover, that can still produce a good sounding speaker; good sounding from the perspective of typical consumers, though admittedly falling far short of the level of perfection that most Obsessive-Compulsive DIY designers seek.
Again, my point out '$100 question and $1,000 answers' was not directed at Sreten personally, but simply a general plea for perspective. We need to answer the question from the perspective of the needs, skills, and resources available to the questioner. It does no good to tell him he needs 1,000 of hours of training and $1,000 of equipment, if he is simply not in a position to obtain those. Though certainly even I would encourage him to eventually obtain that.
In the case of this person's needs, and based on some assumptions I am making, I would have no trouble recommending an off-the-shelf crossover as a solution. I'm sure both Andy and Sreten are horrified by the idea, but, like it or not, it would produce a pleasant, workable, and even likable result. Though admittedly, it wouldn't produce at or near the level of perfection that they typically strive for.
Finally, we really need to know the likelihood that all these selected speaker really are capable and functional at the selected crossover points?
Finally...finally...(finally....sigh)... if our approach to crossover design is wrong, then no point is served unless you can point us to a better one.
Hey...I'm just saying...
Steve/bluewizard
"Simplicity is not that simple."
No matter how much (or how little) you know, there is always infinitely more knowledge to be learned. But you don't become an astronaut until you learn to fly a plane first. And you don't become a designer of near perfect speakers until you've built a few so-so speakers first.
So again, I think it is necessary to tailor the response to the questioner's skill and resource level. If he needs to know the impedance of the speakers at the crossover frequency, he can simply record test tones onto a CD, and put a resistor in series with the speaker. Then while the tone plays, measure the total applied voltage and the voltage across the resistor and the voltage across the speaker. That should give him enough to determine the impedance with reasonable accuracy. And more importantly it only requires about $30 in parts and equipment (not counting the CD player). That doesn''t require heaps of skill, knowledge, or equipment, and simply needs to be tempered with a dash of common sense.
Again, what we really need is a response from the original poster to give us some idea of his skill and resources, and some idea of the likelihood that his chosen crossovers are correct.
As to will a 'textbook' crossover work, there are plenty of fairly good consumer speakers out there that have basic straight forward 12db crossovers in them, and even a few speaker across quite a range of quality that have a simple single capacitor crossover.
Again, if you are trying to reach a level of perfection, then every little detail must be considered and corrected in the design. But if the person is simply looking for a basic level of function in the crossover, that can still produce a good sounding speaker; good sounding from the perspective of typical consumers, though admittedly falling far short of the level of perfection that most Obsessive-Compulsive DIY designers seek.
Again, my point out '$100 question and $1,000 answers' was not directed at Sreten personally, but simply a general plea for perspective. We need to answer the question from the perspective of the needs, skills, and resources available to the questioner. It does no good to tell him he needs 1,000 of hours of training and $1,000 of equipment, if he is simply not in a position to obtain those. Though certainly even I would encourage him to eventually obtain that.
In the case of this person's needs, and based on some assumptions I am making, I would have no trouble recommending an off-the-shelf crossover as a solution. I'm sure both Andy and Sreten are horrified by the idea, but, like it or not, it would produce a pleasant, workable, and even likable result. Though admittedly, it wouldn't produce at or near the level of perfection that they typically strive for.
Finally, we really need to know the likelihood that all these selected speaker really are capable and functional at the selected crossover points?
Finally...finally...(finally....sigh)... if our approach to crossover design is wrong, then no point is served unless you can point us to a better one.
Hey...I'm just saying...
Steve/bluewizard
Thanks to everyone for the great input!!! I think I may have started a thread that may answer some questions for some others, as well.
As far as the 15" woofer goes it is a mid sixties CTS that was originally a part of a three way system in a console. The 500 Hz number comes from the original speaker cabinet design that mine are based on.
The Trio 8" is from a small Kenwood two way and I planned to use 2500 Hz as a crossover point because the original speaker used it as well.
Both drivers have an 8 ohm impedance.
I planned on using a B-G planar or other type of ribbon tweeter for the high end but that could change and hoped for a usable response to about 18,000 Hz.
I don't really have a budget and am willing to spend what it takes to make these cabinets sing. They measure 48"H X 36"W x 24"D so obviously size isn't an issue. My only real issue is not wanting 30-40 passive components for speakers driven by tube amps with less parts. Rightly or not, I have always thought that simplicity is the best solution for the purest signal. Thanks so much for the previous insights.
As far as the 15" woofer goes it is a mid sixties CTS that was originally a part of a three way system in a console. The 500 Hz number comes from the original speaker cabinet design that mine are based on.
The Trio 8" is from a small Kenwood two way and I planned to use 2500 Hz as a crossover point because the original speaker used it as well.
Both drivers have an 8 ohm impedance.
I planned on using a B-G planar or other type of ribbon tweeter for the high end but that could change and hoped for a usable response to about 18,000 Hz.
I don't really have a budget and am willing to spend what it takes to make these cabinets sing. They measure 48"H X 36"W x 24"D so obviously size isn't an issue. My only real issue is not wanting 30-40 passive components for speakers driven by tube amps with less parts. Rightly or not, I have always thought that simplicity is the best solution for the purest signal. Thanks so much for the previous insights.
Regarding the Trio 8"; when you say "...The Trio 8" is from a small Kenwood two way..." do you mean it is a single raw speaker (a coaxial, two speaker in one) or do you mean it is a speaker-CABINET with a woofer and a tweeter. If it is a single wide range speaker, you might be able to make this work.
If you build a straight forward 3-way 12db crossover to start with, you can then make some additional tweaks to smooth things out later.
If you have you computer rigged up to test speakers, then you are ahead of the game. If not, just build them straight up, then later when you can afford the test equipment, you can work on smoothing them out.
For reference, using free software, I think a person could have a rig up and running for about $150 to $200 (mic, pre-amp, wires, resistors, misc...).
If you are going to pay for software, while I don't know which is best, I would think you would be in the range of $500 to $5000. Though $5000 would only be for a serious designers.
3-way off the shelf crossovers are not going to give you the crossover values you need, but a DIY based on the same principles is going to give you good working results, as are found in many commercial speakers.
I agree with Sreten and Andy, DIY for generic designs will not give you perfection, but they are a step on the road in that direction.
If your midrange is as you imply a general full range single raw speaker, then the selected crossover is probably OK, but higher would actually be better assuming the speaker is capable.
The Tweeter, which everyone you select, must extend down below the selected crossover frequency. The closer the crossover is to the low stated frequency response, the sharper the slopes for the crossover are needed.
Just as an illustration, if you crossover at 2500hz, then you tweeter needs to go down to about in the range of 1500hx to 2000hz. It's more complicated than that, but that is a starting point.
Good Luck.
steve/bluewizard
If you build a straight forward 3-way 12db crossover to start with, you can then make some additional tweaks to smooth things out later.
If you have you computer rigged up to test speakers, then you are ahead of the game. If not, just build them straight up, then later when you can afford the test equipment, you can work on smoothing them out.
For reference, using free software, I think a person could have a rig up and running for about $150 to $200 (mic, pre-amp, wires, resistors, misc...).
If you are going to pay for software, while I don't know which is best, I would think you would be in the range of $500 to $5000. Though $5000 would only be for a serious designers.
3-way off the shelf crossovers are not going to give you the crossover values you need, but a DIY based on the same principles is going to give you good working results, as are found in many commercial speakers.
I agree with Sreten and Andy, DIY for generic designs will not give you perfection, but they are a step on the road in that direction.
If your midrange is as you imply a general full range single raw speaker, then the selected crossover is probably OK, but higher would actually be better assuming the speaker is capable.
The Tweeter, which everyone you select, must extend down below the selected crossover frequency. The closer the crossover is to the low stated frequency response, the sharper the slopes for the crossover are needed.
Just as an illustration, if you crossover at 2500hz, then you tweeter needs to go down to about in the range of 1500hx to 2000hz. It's more complicated than that, but that is a starting point.
Good Luck.
steve/bluewizard
OK, a couple of people have asked, so I have done a quick cull of parts of my old series x-o pages, and put the rest back up on my site.
The page "rlabomb" should look at is
http://members.optusnet.com.au/~gradds55/SeriesXO/series_cross-overs8b.htm
This will be your easiest way of getting a decent sounding speaker, ASSUMING that the drivers have reasonably flat response. You will need to know the impedances, and you will need to use some L-pads on the mid and tweeter to balance the levels.
I use this style of x-os in all my three way designs, but I do choose my drivers VERY carefully first.
Have fun.
ps.. I think I agree with Blue Wizard that the BG ribbon probably needs to come in quite a bit higher. If its an old style 8" it probably reaches up to allow a x-o of around 5k.
The page "rlabomb" should look at is
http://members.optusnet.com.au/~gradds55/SeriesXO/series_cross-overs8b.htm
This will be your easiest way of getting a decent sounding speaker, ASSUMING that the drivers have reasonably flat response. You will need to know the impedances, and you will need to use some L-pads on the mid and tweeter to balance the levels.
I use this style of x-os in all my three way designs, but I do choose my drivers VERY carefully first.
Have fun.
ps.. I think I agree with Blue Wizard that the BG ribbon probably needs to come in quite a bit higher. If its an old style 8" it probably reaches up to allow a x-o of around 5k.
Hi,
FWIW I agree with AG, capacitors and L-pads, regarding which
an oversize inductor (or offset bass/mid c/o point) on the bass
unit would probably be a good idea.
L-pad mid and treble.
First order series mid / treble c/o at > 6kHz for the B-G possibly ....
The bass / mid should be 1st order parallel and assymetric.
Then again 4ft x 3ft x (2ft) cabinets do not need much BSC ....
The series 3-way on AG's page might work ....
BW seems to be taking the high ground ....
I thought that was my job ....
A "straightforward" off the shelf 3-way c/o is IMO a waste of time.
And certainly not very 50'ies style (= as AG said 2 capacitors).
FWIW the simplest measuring equipment is either side of your
head, there is a lot you can surmise using tests bands on a CD.
http://www.zaphaudio.com/Waveguidetmm.html
If the trio 8" is flat (big if) going with a 1" dome in a wave guide
might be an idea. If the Trio is ok then then the values for Zaphs
minimal c/o would be a good (ignoring L5) as a starting point.
This is electrically as simple as it gets, and one of the only ways
to get a reasonably low c/o point, noting the electrical c/o point
is far higher than the acoustical. (which is 2nd order)
(Another example of assymetric electrical c/o points)
(BS = baffle step, C = compensation)
Bass / mid might be more problematic. Its a big cabinet so whilst
BSC is not really a problem the "hump" causes by BS might be.
Another case where electrically assymetric c/o points are needed.
The bass unit also might need zobelling / parallel
capacitor to reduce any midrange bleeding through.
1st order parallel networks are easier to tune and it is far easier
to manipulate assymetric c/o points than the series configuration.
They can also to a degree compensate for response irregularities.
Which using 1/3 octave bands are easy to spot.
If you want it simple and effective ignore "textbook" crossovers.
(noting Zaphs c/o above is ~ 2nd order L/R acoustic but the
crossover components indicate assymetric 1st order electrical)
/sreten.
FWIW I agree with AG, capacitors and L-pads, regarding which
an oversize inductor (or offset bass/mid c/o point) on the bass
unit would probably be a good idea.
L-pad mid and treble.
First order series mid / treble c/o at > 6kHz for the B-G possibly ....
The bass / mid should be 1st order parallel and assymetric.
Then again 4ft x 3ft x (2ft) cabinets do not need much BSC ....
The series 3-way on AG's page might work ....
BW seems to be taking the high ground ....
I thought that was my job ....
A "straightforward" off the shelf 3-way c/o is IMO a waste of time.
And certainly not very 50'ies style (= as AG said 2 capacitors).
FWIW the simplest measuring equipment is either side of your
head, there is a lot you can surmise using tests bands on a CD.
http://www.zaphaudio.com/Waveguidetmm.html
If the trio 8" is flat (big if) going with a 1" dome in a wave guide
might be an idea. If the Trio is ok then then the values for Zaphs
minimal c/o would be a good (ignoring L5) as a starting point.
This is electrically as simple as it gets, and one of the only ways
to get a reasonably low c/o point, noting the electrical c/o point
is far higher than the acoustical. (which is 2nd order)
(Another example of assymetric electrical c/o points)
(BS = baffle step, C = compensation)
Bass / mid might be more problematic. Its a big cabinet so whilst
BSC is not really a problem the "hump" causes by BS might be.
Another case where electrically assymetric c/o points are needed.
The bass unit also might need zobelling / parallel
capacitor to reduce any midrange bleeding through.
1st order parallel networks are easier to tune and it is far easier
to manipulate assymetric c/o points than the series configuration.
They can also to a degree compensate for response irregularities.
Which using 1/3 octave bands are easy to spot.
If you want it simple and effective ignore "textbook" crossovers.
(noting Zaphs c/o above is ~ 2nd order L/R acoustic but the
crossover components indicate assymetric 1st order electrical)
/sreten.Hi,
I'll just add as a further note, using Zaphs design as an example :
The design is 2nd order L/R at 3KHz - Acoustic
You will find this in "crossover cookbooks" but only in electrical form,
and it will generally assume the drivers are the same sensitivity,
impedance and both are flat in response over the crossover region.
This is hardly ever true, so a cookbook 2nd order L/R is pointless.
If you use one you have no idea of the acoustic function you have.
the design is 1st order electrical, assuming 8 ohm drivers,
ignoring the BSC 0.5 driver, and looking at the mid/treble c/o :
The lowpass is set to 1.8kHz and the highpass to 9kHz.
Try finding that in a cook book.
In particular the 1st order electrical on the tweeter works well
because it is so high, negating tweeter power handling issues
with low order electrical networks.
Nowhere in any "cookbook" will lead you to the
simplicity and sophistication used in Zaphs design.
Contrary to what was previously started there are not plently
of commercial speakers with "straightforward" 12dB crossovers.
I've previously opined crossover "cookbooks" are the devils spawn.
They miss the point entirely and let you pretend you know what you are doing.
Having some idea of what is actually going on is more important.
/sreten.
I'll just add as a further note, using Zaphs design as an example :
The design is 2nd order L/R at 3KHz - Acoustic
You will find this in "crossover cookbooks" but only in electrical form,
and it will generally assume the drivers are the same sensitivity,
impedance and both are flat in response over the crossover region.
This is hardly ever true, so a cookbook 2nd order L/R is pointless.
If you use one you have no idea of the acoustic function you have.
the design is 1st order electrical, assuming 8 ohm drivers,
ignoring the BSC 0.5 driver, and looking at the mid/treble c/o :
The lowpass is set to 1.8kHz and the highpass to 9kHz.
Try finding that in a cook book.
In particular the 1st order electrical on the tweeter works well
because it is so high, negating tweeter power handling issues
with low order electrical networks.
Nowhere in any "cookbook" will lead you to the
simplicity and sophistication used in Zaphs design.
Contrary to what was previously started there are not plently
of commercial speakers with "straightforward" 12dB crossovers.
I've previously opined crossover "cookbooks" are the devils spawn.
They miss the point entirely and let you pretend you know what you are doing.
Having some idea of what is actually going on is more important.
/sreten.- Status
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