Its All Your Fault, Dave!!
Dave,
I am going to wind the clock back and reveal how I got myself into this predicament.
After I moved to Sydney, Australia in June 2001, I had to put a audio system together, since I had left my system in my place in the States. I went to see an older gentlemen who had the largest collection of Hi-Fi gear I have ever seen. He must have had 40 pairs of speakers, and dozens of amp, CD players, turntables, tape decks, etc. all good stuff from all vintages. Anyway, I was looking at his speakers and he pointed to a big speaker and said, "That is the speaker you need, it has one 12" driver." I laugh and said, "Yeah, right" and discounted it as one those old things, like those old tube amps. Well..... If I had known then what I know now, it was a big baffle speaker with a 12" Goodman. That planted the seed. Then I stumbled onto your site, t-linespeakers.org, and I was intrigued. Well, too cut the story short, I just had to see for myself. I found a pair of 8" full range-drivers from out of an old console unit(Miller & Kriesler?) along side the road. I picked up an old no name Class A amp from a scrap pile. Talk about cheap, but I was skeptic and did not want to spend any money on something I did not think would work. I stuck the drivers in T-line similiar to your Toobz, wired everything up, unbelievable, I could not believe what I was hearing. I retired my big three-ways after I played with the line and driver a bit. I could tweak it more, but I am hooked on the sound of no-cross-over or almost no cross-over, and want to build a "reference" set of speakers. So I have you to blame because of your enthusiasm about vintage and wide-range drivers and t-lines that motivated me to give it a try. I have been salvaging vintage drivers from everywhere, but have not yet run into any of your favorites the Fostex FE103A.
So I have been going through real transition, from big mega watt systems to wanting to build one of those "old" tube amps and all I can think about is how good it will sound with an efficient system.
I am aware that driver companies spend a huge amounts of money improving their drivers, and there is not a question that the woofers we have today have no equal, and tweeters we could only dream of for years. And, of course, these advancements cost money. But.... that does not mean that there are not vintage drivers of exception quality.
So there you have it, and you can bear the full brunt of guilt of my affliction!!!
Cheers,
Lynn
Dave,
I am going to wind the clock back and reveal how I got myself into this predicament.
After I moved to Sydney, Australia in June 2001, I had to put a audio system together, since I had left my system in my place in the States. I went to see an older gentlemen who had the largest collection of Hi-Fi gear I have ever seen. He must have had 40 pairs of speakers, and dozens of amp, CD players, turntables, tape decks, etc. all good stuff from all vintages. Anyway, I was looking at his speakers and he pointed to a big speaker and said, "That is the speaker you need, it has one 12" driver." I laugh and said, "Yeah, right" and discounted it as one those old things, like those old tube amps. Well..... If I had known then what I know now, it was a big baffle speaker with a 12" Goodman. That planted the seed. Then I stumbled onto your site, t-linespeakers.org, and I was intrigued. Well, too cut the story short, I just had to see for myself. I found a pair of 8" full range-drivers from out of an old console unit(Miller & Kriesler?) along side the road. I picked up an old no name Class A amp from a scrap pile. Talk about cheap, but I was skeptic and did not want to spend any money on something I did not think would work. I stuck the drivers in T-line similiar to your Toobz, wired everything up, unbelievable, I could not believe what I was hearing. I retired my big three-ways after I played with the line and driver a bit. I could tweak it more, but I am hooked on the sound of no-cross-over or almost no cross-over, and want to build a "reference" set of speakers. So I have you to blame because of your enthusiasm about vintage and wide-range drivers and t-lines that motivated me to give it a try. I have been salvaging vintage drivers from everywhere, but have not yet run into any of your favorites the Fostex FE103A.
So I have been going through real transition, from big mega watt systems to wanting to build one of those "old" tube amps and all I can think about is how good it will sound with an efficient system.
I am aware that driver companies spend a huge amounts of money improving their drivers, and there is not a question that the woofers we have today have no equal, and tweeters we could only dream of for years. And, of course, these advancements cost money. But.... that does not mean that there are not vintage drivers of exception quality.
So there you have it, and you can bear the full brunt of guilt of my affliction!!!
Cheers,
Lynn
The Australian Fostex Agent is:
<a href="http://www.syntec.com.au/">Syntec Australia</a>
60 Gibbes Street
Chatswood NSW 2067 AUSTRALIA
Phone: +61 (02) 9417 4700
Fax: +61 (02) 9417 6136
eMail: sales@syntec.com.au
service@syntec.com.au
The Fostex link just sends you to Fostex.com, Syntec mainly handle studio equipment.
<hr width="95%" align=center>
Not sure if you are aware that the Bandors are made by Ted Jordans Ex-wife, the intellectual property was split in the settlement.
Regards
James
<a href="http://www.syntec.com.au/">Syntec Australia</a>
60 Gibbes Street
Chatswood NSW 2067 AUSTRALIA
Phone: +61 (02) 9417 4700
Fax: +61 (02) 9417 6136
eMail: sales@syntec.com.au
service@syntec.com.au
The Fostex link just sends you to Fostex.com, Syntec mainly handle studio equipment.
<hr width="95%" align=center>
Not sure if you are aware that the Bandors are made by Ted Jordans Ex-wife, the intellectual property was split in the settlement.
Regards
James
If you are interested, I have a couple of pairs of the RS 40-1197's (nee - FE 103) that are now surplus to my needs. Both pairs have been treated with doping of the cone and one pair sans dustcap with phase plug fitted reside at the moment in a pair of Buschorn MKII rear loaded horns. The phase plug flattened the peak at the top end quite nicely. Fortunately I can verify all mods through my IMP Audio Analyzer... The sound is simply amazing from what is a tiny driver, but I am moving on to bigger ( though not necessarely better! ) things. I live in South Oz, so if you are interested let me know, otherwise I'll be putting them up on ebay sometime in the near future...
tomcat
tomcat
It's funny how so many people are leaning toward this type of design... I find myself being one of them.
My take on it is this: Use a very small 3-4" drivers for the mid, and use a bunch of them spaced as close together as possible... this should cause the IM distortion to decrease as a result of the shared power handling and lower excursion among the drivers. I'm not talking line array here- maybe more of a "grouped" array, with the drivers not extending vertically any farther in the vertical axis than where they can produce a flat response at that position referenced to the listener. I would cross to a ribbon tweeter, probably 2nd order, for a good compromise of stifling harsh highs in the mids and ease of design- the frequency would be limited by the dispersion characteristics of the mids, of course. I would use a fourth order electronic crossover somewhere in the 100-200Hz range, dependant on the mids resonant frequency, and cross to two 8 or 10 inch woofers.This is just my take on it.
I really like the idea of the mid driver creating the tone of the system, and augmenting it with suitable drivers to fill in the extremes of the audio spectrum. I believe the magic is to be found in the mids, and it's too often compromised in traditional systems- seems like it should be the focal point of the system.
Steve
My take on it is this: Use a very small 3-4" drivers for the mid, and use a bunch of them spaced as close together as possible... this should cause the IM distortion to decrease as a result of the shared power handling and lower excursion among the drivers. I'm not talking line array here- maybe more of a "grouped" array, with the drivers not extending vertically any farther in the vertical axis than where they can produce a flat response at that position referenced to the listener. I would cross to a ribbon tweeter, probably 2nd order, for a good compromise of stifling harsh highs in the mids and ease of design- the frequency would be limited by the dispersion characteristics of the mids, of course. I would use a fourth order electronic crossover somewhere in the 100-200Hz range, dependant on the mids resonant frequency, and cross to two 8 or 10 inch woofers.This is just my take on it.
I really like the idea of the mid driver creating the tone of the system, and augmenting it with suitable drivers to fill in the extremes of the audio spectrum. I believe the magic is to be found in the mids, and it's too often compromised in traditional systems- seems like it should be the focal point of the system.
Steve
I found another speaker using the Bandor Drivers in a modular line array, <a href="http://www.audience-av.com/speakers.htm">audience-av</a>.
I was hoping to find some details on the speaker Mataxas made using the 50mm module, that way you could possibly audition one, but now he seems just to have his electrostats.
Regards
James
I was hoping to find some details on the speaker Mataxas made using the 50mm module, that way you could possibly audition one, but now he seems just to have his electrostats.
Regards
James
I Am Digging My Heels In!!
I am going to show my stubborn streak here, but I am not having a crossover to the woofer any higher than 90HZ and I starting to feel like I will try to push it as low as 80Hz.
Why am I insistent on this? If you do your home work, you will find that Middle C or C4 is 261.63Hz. Now if you know anything about music, you know that the entire music scale revolves around this frequency. When you read or write music, you have C4 squarely in the middle(hint, that is why it is called middle C) between the Treble(G)-Clef staff and Bass(C)-Clef staff(OK, I am sure someone will try to remind me of the Alto-Clef, which is used for instruments and singers in the Alto range and has Middle C as the middle staff line). You have Bass below Middle C and Soprano above Middle C with Tenor overlapping from the bottom and Alto overlapping from the top. All instruments and vocals are referenced in this way. So, human vocals range from C2@65HZ or 2 Octaves below middle Middle C or C4@261Hz at the extreme low end to C7@2,093Hz or 3 Octaves above Middle C or C4@261Hz at the extreme high end. The average would from F2@87Hz to G6@1,567Hz. These are the fundamental frequencies, and if you check your references, you will find that a violin only goes several notes higher than the best soprano along with a flute, piano, organ and a few other wind and reed instruments.
Traditionally mid-range has been classified from 300Hz to 3,000Hz, but if you look at the following link - http://www.modernrecording.com/resources/charts/freqs.shtml - which shows the fundamental frequencies laid on a piano keyboard , you will see that 300Hz is very close to D4@293Hz or about one step above Middle C. That is the top of the Bass range and any tenor will be very comfortable singing that note, hardly the bottom of the vocal range, closer to the middle. I am proposing for this project that we classify mid-range as the fundamental range of the human voice, which actually covers most of fundamental range of most instruments, with exception of your bass range instruments like the bassoon, bass guitar and such.
I know this is redundant from my first post, but I believe that if you listen to any acapella music you will hear why I am taking this stance. Stringed and wind instruments have a large amount of second and higher harmonics which identifies them to your ear, but in my experience, the human voice has much fewer harmonics and is closer to the fundamental note and this makes it easier to hear the different notes being sung. When you change a half-step, a flat or a sharp, in music it makes a huge difference, very audible difference. Many conductors and voice teachers will tell you that when you sing up the scale you must hop up and land on the next note from the top, or you will have the tendency to flatten the note, or if you are going down the scale you must step down onto the next note squarely or you will sharpen the note, which is audible, although in reality it may on be only a few hertz difference. A sharp or flat, raises or lowers the scale by a half of step, which in the bass range can be as little as 5Hz to as much as 80Hz in the Soprano range. These diffences are clearly audible, you have to be tone deaf not to hear the difference, but in many speakers these are hard to discern, especially below 120Hz. Play some acapella music that covers most vocal range and see if you can hear when a bass singer makes a move from a C to C# or even D. Without the overlapping harmonics of instruments, it should stick out like a sore thumb, if not your speakers need rebuilt. Mine do. We are after clean, clear bass, not this one-note stuff.
I am sure that I have bored some of you to death by now, but this was all triggered by me receiving a CD from a friend in the States with acapella music being sung by one of the best choruses in the East. I know the sound engineer personally and know that he is a real stickler for maintaining originality and purity in his recordings. I have actually been with him and helped with recordings in his studio. So when I received this CD and started listening, I decided it was time to find new speakers. I have tried it on every pair I own, including 2-way towers, three-ways and my full-ranges.
So back to the start of this rant, I am looking for a driver that covers from <90Hz to >4,000Hz in one blow, with a minimum of IM and dipersion problems. This is one parameter of this project we can set in stone. I said in a post before that we may have to stretch the envelope a bit. Now you know why.
Having said all of the above, I am not discounting the importance of the second, third and etc. harmonics, which range all the way to 20,000Hz, and are absolutely vital for the identification of different voices and instruments. Each individual human or animal voice and instrument has its own unique signature of harmonics, without which you would not be able to identify who was talking to you without seeing their face or what instrument is playing. Basically, music is your fundamental note with the signature of the source overlaid.
James. I have been in touch with Syntec, and am waiting for them to reply. And thanks for the link. I am still waiting to hear from Bandor.
Mark, the FF225K is a possiblity, but again I am waiting for details on the availability of Fostex drivers here in OZ.
Tomcat, E-mail me and we will dicuss the 40-1197's that you have. I would also be interested in seeing your specs on these drivers with the mods you have made to them.
Steve, I am not opposed to your idea of a group array or some other multiple driver idea, but it must be able to reach down too at least 90Hz.
I know I sound obstinate and I am, but anything else will just be another 3 way system. I also promise not to repeat this rant again.
Lynn
I am going to show my stubborn streak here, but I am not having a crossover to the woofer any higher than 90HZ and I starting to feel like I will try to push it as low as 80Hz.
Why am I insistent on this? If you do your home work, you will find that Middle C or C4 is 261.63Hz. Now if you know anything about music, you know that the entire music scale revolves around this frequency. When you read or write music, you have C4 squarely in the middle(hint, that is why it is called middle C) between the Treble(G)-Clef staff and Bass(C)-Clef staff(OK, I am sure someone will try to remind me of the Alto-Clef, which is used for instruments and singers in the Alto range and has Middle C as the middle staff line). You have Bass below Middle C and Soprano above Middle C with Tenor overlapping from the bottom and Alto overlapping from the top. All instruments and vocals are referenced in this way. So, human vocals range from C2@65HZ or 2 Octaves below middle Middle C or C4@261Hz at the extreme low end to C7@2,093Hz or 3 Octaves above Middle C or C4@261Hz at the extreme high end. The average would from F2@87Hz to G6@1,567Hz. These are the fundamental frequencies, and if you check your references, you will find that a violin only goes several notes higher than the best soprano along with a flute, piano, organ and a few other wind and reed instruments.
Traditionally mid-range has been classified from 300Hz to 3,000Hz, but if you look at the following link - http://www.modernrecording.com/resources/charts/freqs.shtml - which shows the fundamental frequencies laid on a piano keyboard , you will see that 300Hz is very close to D4@293Hz or about one step above Middle C. That is the top of the Bass range and any tenor will be very comfortable singing that note, hardly the bottom of the vocal range, closer to the middle. I am proposing for this project that we classify mid-range as the fundamental range of the human voice, which actually covers most of fundamental range of most instruments, with exception of your bass range instruments like the bassoon, bass guitar and such.
I know this is redundant from my first post, but I believe that if you listen to any acapella music you will hear why I am taking this stance. Stringed and wind instruments have a large amount of second and higher harmonics which identifies them to your ear, but in my experience, the human voice has much fewer harmonics and is closer to the fundamental note and this makes it easier to hear the different notes being sung. When you change a half-step, a flat or a sharp, in music it makes a huge difference, very audible difference. Many conductors and voice teachers will tell you that when you sing up the scale you must hop up and land on the next note from the top, or you will have the tendency to flatten the note, or if you are going down the scale you must step down onto the next note squarely or you will sharpen the note, which is audible, although in reality it may on be only a few hertz difference. A sharp or flat, raises or lowers the scale by a half of step, which in the bass range can be as little as 5Hz to as much as 80Hz in the Soprano range. These diffences are clearly audible, you have to be tone deaf not to hear the difference, but in many speakers these are hard to discern, especially below 120Hz. Play some acapella music that covers most vocal range and see if you can hear when a bass singer makes a move from a C to C# or even D. Without the overlapping harmonics of instruments, it should stick out like a sore thumb, if not your speakers need rebuilt. Mine do. We are after clean, clear bass, not this one-note stuff.
I am sure that I have bored some of you to death by now, but this was all triggered by me receiving a CD from a friend in the States with acapella music being sung by one of the best choruses in the East. I know the sound engineer personally and know that he is a real stickler for maintaining originality and purity in his recordings. I have actually been with him and helped with recordings in his studio. So when I received this CD and started listening, I decided it was time to find new speakers. I have tried it on every pair I own, including 2-way towers, three-ways and my full-ranges.
So back to the start of this rant, I am looking for a driver that covers from <90Hz to >4,000Hz in one blow, with a minimum of IM and dipersion problems. This is one parameter of this project we can set in stone. I said in a post before that we may have to stretch the envelope a bit. Now you know why.
Having said all of the above, I am not discounting the importance of the second, third and etc. harmonics, which range all the way to 20,000Hz, and are absolutely vital for the identification of different voices and instruments. Each individual human or animal voice and instrument has its own unique signature of harmonics, without which you would not be able to identify who was talking to you without seeing their face or what instrument is playing. Basically, music is your fundamental note with the signature of the source overlaid.
James. I have been in touch with Syntec, and am waiting for them to reply. And thanks for the link. I am still waiting to hear from Bandor.
Mark, the FF225K is a possiblity, but again I am waiting for details on the availability of Fostex drivers here in OZ.
Tomcat, E-mail me and we will dicuss the 40-1197's that you have. I would also be interested in seeing your specs on these drivers with the mods you have made to them.
Steve, I am not opposed to your idea of a group array or some other multiple driver idea, but it must be able to reach down too at least 90Hz.
I know I sound obstinate and I am, but anything else will just be another 3 way system. I also promise not to repeat this rant again.
Lynn
I Ran Some Numbers
Ok, here is what I came up after plugging in some numbers into Uni-box.
The Fostex drivers will just not get down as low as I want without a horn or vent. I really want to use a sealed box for the midrange to keep the response as clean as possible.
I am left with the following drivers -
Bandor 50 AFS W/8 - A sealed 16 liter box with heavy fill gives a QTC of .707 and F3 of 68HZ. With a F3 well under my target and dispersion of minimal concern, this driver is my first choice except for its gross inefficiency of around 85db. The factory response graph show a nice clean, flat response in the lower frequencies.
Bandor 100 DW 8A - A sealed 9 liter box with heavy fill gives a QTC of .708 and a F3 of 63Hz. This driver gives better efficiency, but we have serious dispersion concerns starting around 2,000 to 3,000Hz.
Jordan JX92S - A sealed 1.7? liter box with minimal fill gives a QTC of .711 with a F3 of 74Hz. A great driver but have the same dispersion concerns as the Bandor 100.
It is after midnight, so I have no problems if you run the numbers and find I have made an error. All the above drivers are really great, high quality goods, but I am not happy with the efficiencies all below 90db. Because I ultimately want to power all this with tubes, I was looking for efficiency in the low 90's.
Any better suggestions?
Lynn
Ok, here is what I came up after plugging in some numbers into Uni-box.
The Fostex drivers will just not get down as low as I want without a horn or vent. I really want to use a sealed box for the midrange to keep the response as clean as possible.
I am left with the following drivers -
Bandor 50 AFS W/8 - A sealed 16 liter box with heavy fill gives a QTC of .707 and F3 of 68HZ. With a F3 well under my target and dispersion of minimal concern, this driver is my first choice except for its gross inefficiency of around 85db. The factory response graph show a nice clean, flat response in the lower frequencies.
Bandor 100 DW 8A - A sealed 9 liter box with heavy fill gives a QTC of .708 and a F3 of 63Hz. This driver gives better efficiency, but we have serious dispersion concerns starting around 2,000 to 3,000Hz.
Jordan JX92S - A sealed 1.7? liter box with minimal fill gives a QTC of .711 with a F3 of 74Hz. A great driver but have the same dispersion concerns as the Bandor 100.
It is after midnight, so I have no problems if you run the numbers and find I have made an error. All the above drivers are really great, high quality goods, but I am not happy with the efficiencies all below 90db. Because I ultimately want to power all this with tubes, I was looking for efficiency in the low 90's.
Any better suggestions?
Lynn
Lynn
Have a look at the Audax range:
http://www.audax.com/doit/index.shtml
The HD-A 4" mid-range (HM100ZO) probably won't go as low as you are looking for but is otherwise excellent. The 5.25" (HM130ZO) goes somewhat lower and doesn't lose too much at the top end. There are now several varieties of the 5.25" driver so you will need to check which one has the best performance compromise for your needs.
My datasheets are now 8 years old so there may have been changes, but the 5.25" and 6.5" carbon fibre coned drivers (HM130CO and HM170CO) seem to have a wider usable bandwith than the HD-A cones. Unfortunately the Audax site does not have the datasheets for these but I can scan them for you if you are interested. The carbon fibre drivers are 90dB/W and the HD-A 92 & 93dB/W.
Geoff
Have a look at the Audax range:
http://www.audax.com/doit/index.shtml
The HD-A 4" mid-range (HM100ZO) probably won't go as low as you are looking for but is otherwise excellent. The 5.25" (HM130ZO) goes somewhat lower and doesn't lose too much at the top end. There are now several varieties of the 5.25" driver so you will need to check which one has the best performance compromise for your needs.
My datasheets are now 8 years old so there may have been changes, but the 5.25" and 6.5" carbon fibre coned drivers (HM130CO and HM170CO) seem to have a wider usable bandwith than the HD-A cones. Unfortunately the Audax site does not have the datasheets for these but I can scan them for you if you are interested. The carbon fibre drivers are 90dB/W and the HD-A 92 & 93dB/W.
Geoff
Audax
Geoff,
I have looked at the Audax web-site several times, but I have not been able to find any spec sheets for their drivers. I would love to see the spec sheets you just mentioned, if it is not too much trouble. Do you know of anywhere that has a complete set of spec sheets for their drivers?
Here is my E-mail - longboard@froggy.com.au
Thanks,
Lynn
Geoff,
I have looked at the Audax web-site several times, but I have not been able to find any spec sheets for their drivers. I would love to see the spec sheets you just mentioned, if it is not too much trouble. Do you know of anywhere that has a complete set of spec sheets for their drivers?
Here is my E-mail - longboard@froggy.com.au
Thanks,
Lynn
Lynn
The HD-A spec sheets are on Audax's website. From the products page, select say 5.25" and HD-A. In the resulting list, you can click on a particular model and will get a specification table and the options to display a response curve and waterfall plot.
I have your email address from previous correspondence. The carbon fibre datasheets will be in your mailbox when you get up tomorrow (assuming that you are going to go to bed sometime
Geoff
The HD-A spec sheets are on Audax's website. From the products page, select say 5.25" and HD-A. In the resulting list, you can click on a particular model and will get a specification table and the options to display a response curve and waterfall plot.
I have your email address from previous correspondence. The carbon fibre datasheets will be in your mailbox when you get up tomorrow (assuming that you are going to go to bed sometime
Geoff
The Focal 5" 5k3211b midbass unit has excellent sound and dispersion characteristics(3db max. deviation) up to about 4.2-4.5 Khz. In a sealed enclosure, they exhibit F3 as low as approx. 90 Hz. (Of course, don't expect high output levels at this low frequency without a very steep crossover to limit lower freq. information.) Another benefit of this driver is the damping core sandwhiched between the kevlar which prevents the predominant resonance problems associated with most other super stiff kevlar, carbon fiber, etc. cones.
-Chris
-Chris
A Whimsical Suggestion
From what I have read, vertical arrays have comb effects.
I also read that these effects come from the distance between the centers being a wavelength and half wavelength apart at various frequencies, giving reinforcement and cancellation effects.
What would happen if there were three 4 inchers in a vertical array? At 3400 Hz, for instance, the middle speaker is reinforcing with the top speaker and the bottom speaker. But the top and the bottom speaker are cancelling each other because it they are a half wavelength apart. Hopefully, everything works out.
I have no experience actually doing this, but it might be a way to get more vibrating area for the midrange while not limiting the horizontal dispersion. If it works.
Just a suggestion to maybe experiment with.
From what I have read, vertical arrays have comb effects.
I also read that these effects come from the distance between the centers being a wavelength and half wavelength apart at various frequencies, giving reinforcement and cancellation effects.
What would happen if there were three 4 inchers in a vertical array? At 3400 Hz, for instance, the middle speaker is reinforcing with the top speaker and the bottom speaker. But the top and the bottom speaker are cancelling each other because it they are a half wavelength apart. Hopefully, everything works out.
I have no experience actually doing this, but it might be a way to get more vibrating area for the midrange while not limiting the horizontal dispersion. If it works.
Just a suggestion to maybe experiment with.
To: Planet 10 and SSS
Paul and Lyn,
At this stage I can't provide any pictures of the modified
RS 40-1197 as I don't have any photos nor do I have a scanner, but I will be getting lend of a digital camera from a friend at a later date as I have a few bits'n'peices I want to put on ebay. I have before and after frequency response plots that I can fax you guys if you have access to one. Email me the number and I'll send it through to you guys with some explanationary notes... As an interesting aside, I'm not at all surprised at the similarity between the Bandor and Jordan units since Bandor is manufactured by Ted Jordans ex, Doreen. I remember a constructional article penned by Ted Jordan in the 70's and published in "Practical Hi-Fi" featuring these units, at the time refered to as modules by him. The design was a line array of four of these units in a sealed enclosure on top of a reflex loaded Jordan woofer, the whole lot tied together through a very simple 1st order 'series' x/over with just one cap and one large value inductor @ 150Hz. At the time I scoffed at the whole concept including the x/over because it was becoming fashionable at the time to use more complex 3rd & 4th order networks. Yet laterly the more I play around with speakers and x/overs the more I am convinced that he was on the right track in many areas ( he must have been since he is still around making the same drivers almost 30 years later! ) not the least of which is the use of series, self ballancing networks....
but that's another story entirely
tomcat
Paul and Lyn,
At this stage I can't provide any pictures of the modified
RS 40-1197 as I don't have any photos nor do I have a scanner, but I will be getting lend of a digital camera from a friend at a later date as I have a few bits'n'peices I want to put on ebay. I have before and after frequency response plots that I can fax you guys if you have access to one. Email me the number and I'll send it through to you guys with some explanationary notes... As an interesting aside, I'm not at all surprised at the similarity between the Bandor and Jordan units since Bandor is manufactured by Ted Jordans ex, Doreen. I remember a constructional article penned by Ted Jordan in the 70's and published in "Practical Hi-Fi" featuring these units, at the time refered to as modules by him. The design was a line array of four of these units in a sealed enclosure on top of a reflex loaded Jordan woofer, the whole lot tied together through a very simple 1st order 'series' x/over with just one cap and one large value inductor @ 150Hz. At the time I scoffed at the whole concept including the x/over because it was becoming fashionable at the time to use more complex 3rd & 4th order networks. Yet laterly the more I play around with speakers and x/overs the more I am convinced that he was on the right track in many areas ( he must have been since he is still around making the same drivers almost 30 years later! ) not the least of which is the use of series, self ballancing networks....
but that's another story entirely
tomcat
Did you say that you planned to cross over at 6K? This is a discontinued Vifa model, available at Parts Express for $25. I am not sure if this is the one that Tomcat mentioned earlier. Flat to 4K, natural rolloff right at the 6K area. You might want to let this roll off naturally in the crossover area, setting your crossover components for farther up the scale, thereby ameliorating the phase distortion that occurs with crossovers.
Parts Express number 299-243
Vifa P11 WG-008
http://www.partsexpress.com/pe/showdetl.cfm?st=0&st2=0&st3=0&DID=7&Product_ID=67940&DS_ID=3
Listed sensitivity is 86 dB@1W/1M. 8 ohm. Hook them up in parallel, and the sensitivity goes up 3 dB or 6 dB, depending on whether you are measuring 1 genuine watt or 2.83 volts.
Parts Express has them on a buyout, but some places in Australia might still have them in stock. Of course, if there is an Audax that is currently being made that offers similar performance, it is to your advantage to go in that direction, for replacement purposes.
Anyway, here is the response chart, complete with 30 deg and 60 deg off-axis response. The off-axis response probably applies as much to any 4 inch driver as it does to the Vifa.
Parts Express number 299-243
Vifa P11 WG-008
http://www.partsexpress.com/pe/showdetl.cfm?st=0&st2=0&st3=0&DID=7&Product_ID=67940&DS_ID=3
Listed sensitivity is 86 dB@1W/1M. 8 ohm. Hook them up in parallel, and the sensitivity goes up 3 dB or 6 dB, depending on whether you are measuring 1 genuine watt or 2.83 volts.
Parts Express has them on a buyout, but some places in Australia might still have them in stock. Of course, if there is an Audax that is currently being made that offers similar performance, it is to your advantage to go in that direction, for replacement purposes.
Anyway, here is the response chart, complete with 30 deg and 60 deg off-axis response. The off-axis response probably applies as much to any 4 inch driver as it does to the Vifa.
Attachments
The Vifa, while having adequate HF response characteristics would not seem to be able to meet surf's outlined LF requirements for a mid driver.
In a sealed box, a maximum output of well under 100db/1m, at 95 Hz...with very rapid overexcurcion occuring as soon as 90 Hz at 96db, even 2 of these per cabinet would provide inadequate output levels IMO.
Maybe if LF demands were not so stringet, this would work adequately crossed at around 120-130 Hz, or if surf wished to compromise this critical range by using a ported alignment, it could be crossed 100-110 Hz.
-Chris
In a sealed box, a maximum output of well under 100db/1m, at 95 Hz...with very rapid overexcurcion occuring as soon as 90 Hz at 96db, even 2 of these per cabinet would provide inadequate output levels IMO.
Maybe if LF demands were not so stringet, this would work adequately crossed at around 120-130 Hz, or if surf wished to compromise this critical range by using a ported alignment, it could be crossed 100-110 Hz.
-Chris
Kelticwizard... this is not the Vifa driver
Sorry, this is not the driver I was refering to... the one I had in mind had a white cone and went past 10k and about 86dB. It was a one off special Vifa made as an OEM that Pts Xps baught up. I did a search and it seems that it is no longer available... Pity 'bout that.
Sorry, this is not the driver I was refering to... the one I had in mind had a white cone and went past 10k and about 86dB. It was a one off special Vifa made as an OEM that Pts Xps baught up. I did a search and it seems that it is no longer available... Pity 'bout that.