Hello!
I have long been fascinated of the Dunlavys and would likte to build omething alike the SC IV.
Ia hve read and read and read everything i can about them and alo ought out what drivers they used. I didnt find exactly all drivers but a fair deal of them, but they are all out of production except their D27TG35 tweeter. I think their mids were Vifa M13 of some variant, and P13 in the SC6. I would like to build a pair for myself and my studio If i could buy the original driver i would have done that, but it is out of question.
So, I turn to you. I can get hold of the PDFs of the original drivers used in the SC, but my thinking is this that these drivers are atleast 30 year old designs. There has to be similiar driver today that are a bit more modern, with for example ventilation under the spider, copper in the motor, and more evolved motors and hopefully other upgrades.
Iam quite knowledgeable of speaker building and these arent my first project, far from it. Im able to simulate and create crosovers with my Line Audio OM1 meaurement microphone and Holmimpule and ARTA, crosovers I simulate at the moment with Xsim until i have learnt vituixcad.
The SC uses an ordinary old Vifa D26/7, my idea is to change it out to a waveguided tweeter with the 105mm diameter as D27 has, probably the Wavecore TW030WA11 or 12 depending on what the ohter drivers will be 4 or 8 ohm.
But, I am kind of stuck on what to use as mids and woofers.. One idea I had was using Peerless SLS as woofers as they shall be closed boxes true to Mr. Dunlavys ideal.
But when it comes to mids, I really dont know what tp go with.. Can you give me some ideas, but REMEMBER, all drivers suggested should be suitable for first order crossovers.
Im fully aware that there will be alot of components in the crosssover to beat the drivers in form for true first order crossovers.
What do you think?
I aim for a height of the speakers at around 150-160cm high, with about 30cm baffle width. Depth, will be whats necessary.
True to Dunlavys ideas, the baffle will be stepped and drivers time aligned, that is just a must in all speakers i build, the benefits are so good that i realla cant understad why people dont do it...
Sounds like a good idea in my head, but what do you guys feel?
Best wishes, MIJK
I have long been fascinated of the Dunlavys and would likte to build omething alike the SC IV.
Ia hve read and read and read everything i can about them and alo ought out what drivers they used. I didnt find exactly all drivers but a fair deal of them, but they are all out of production except their D27TG35 tweeter. I think their mids were Vifa M13 of some variant, and P13 in the SC6. I would like to build a pair for myself and my studio If i could buy the original driver i would have done that, but it is out of question.
So, I turn to you. I can get hold of the PDFs of the original drivers used in the SC, but my thinking is this that these drivers are atleast 30 year old designs. There has to be similiar driver today that are a bit more modern, with for example ventilation under the spider, copper in the motor, and more evolved motors and hopefully other upgrades.
Iam quite knowledgeable of speaker building and these arent my first project, far from it. Im able to simulate and create crosovers with my Line Audio OM1 meaurement microphone and Holmimpule and ARTA, crosovers I simulate at the moment with Xsim until i have learnt vituixcad.
The SC uses an ordinary old Vifa D26/7, my idea is to change it out to a waveguided tweeter with the 105mm diameter as D27 has, probably the Wavecore TW030WA11 or 12 depending on what the ohter drivers will be 4 or 8 ohm.
But, I am kind of stuck on what to use as mids and woofers.. One idea I had was using Peerless SLS as woofers as they shall be closed boxes true to Mr. Dunlavys ideal.
But when it comes to mids, I really dont know what tp go with.. Can you give me some ideas, but REMEMBER, all drivers suggested should be suitable for first order crossovers.
Im fully aware that there will be alot of components in the crosssover to beat the drivers in form for true first order crossovers.
What do you think?
I aim for a height of the speakers at around 150-160cm high, with about 30cm baffle width. Depth, will be whats necessary.
True to Dunlavys ideas, the baffle will be stepped and drivers time aligned, that is just a must in all speakers i build, the benefits are so good that i realla cant understad why people dont do it...
Sounds like a good idea in my head, but what do you guys feel?
Best wishes, MIJK
The most important part is the x-over, you can only reach that flat phase response with 6dB/octave filters between mid/high drivers.
Do you have the X-over values?
That means the mid must have a flat FR until very high freq. a full-range rather.
https://www.scan-speak.dk/datasheet/pdf/12mu-8731t00.pdf
https://www.scan-speak.dk/datasheet/pdf/22w-8534g00.pdf
Do you have the X-over values?
That means the mid must have a flat FR until very high freq. a full-range rather.
https://www.scan-speak.dk/datasheet/pdf/12mu-8731t00.pdf
https://www.scan-speak.dk/datasheet/pdf/22w-8534g00.pdf
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Interesting idea. 
I've answered your PM, there should be a lot of info hidden in the links I've send to you.
Vituixcad will be a good idea to use. But how large is your room? To get the best out of these, you'd need some distance between you and the speaker.
X-over values from existing Dunlavy speakers would be almost useless. As each crossover was tailored to that specific speaker. So hardly ever two crossovers were exactly alike. It will be foor for thought though. Lots of info is out there as learning material. Be prepared to spend a lot of time on it, to learn what he was doing and why.
I've answered your PM, there should be a lot of info hidden in the links I've send to you.
Vituixcad will be a good idea to use. But how large is your room? To get the best out of these, you'd need some distance between you and the speaker.
X-over values from existing Dunlavy speakers would be almost useless. As each crossover was tailored to that specific speaker. So hardly ever two crossovers were exactly alike. It will be foor for thought though. Lots of info is out there as learning material. Be prepared to spend a lot of time on it, to learn what he was doing and why.
Modern way is to use active FIR instead of acoustical 1st order passive. Long list of advantages compared to passive which does not have much good for that type of application.
+1.
That's what Dunlavy himself was doing to improve the SV-VI......a speaker he named Magnus.
Flat baffle, amp for each driver, dsp .... Loudspeaker designer John Dunlavy: By the Numbers... Page 5 | Stereophile.com
Best of both worlds, a truly excellent acoustic speaker design made to perform even better, by simply using modern methods.
Last effort of Dunlavy's was to port his passive design to active filtering. It never happened because of illness he developed.
That said he talked about delaying drivers in order to easier the box built, transcribe his filter design to dsp,...
Sure if he had access to FIR he would have used it i bet.
Edit: Mark was faster than me!
That said he talked about delaying drivers in order to easier the box built, transcribe his filter design to dsp,...
Sure if he had access to FIR he would have used it i bet.
Edit: Mark was faster than me!
Vandersteen believes that as well as Dunlavy did. Other commercial speaker vendors as well, of course. This is probably the single most fundamental decision of a multi-driver speaker design, the objective engineering compromise to choose or not a 1st order crossover.
Any how, I'm wondering whether you are referring to objective or subjective benefits? You seem fairly convinced about this design choice. We well know the objective benefits (and compromises) of 1st order crossovers, so if you are referring to subjective benefits, I'd certainly be interested to read your subjective description of what you feel that you hear via 1st order crossovers that you do not hear via higher order ones. Please understand, that I'm not looking to challenge your decision to go with 1st order. I just want to read about your personal designer's reasons for that choice.
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Asking myself if a Duelund filter type have better subjective better transcient than a 1st order. Imho if only the discussion is about the soundstage then 1st slope is harder.
Are there many commercial designs that used passive coils for timing alignment at he crossover frequencies ? Or did they just use physical offset in the tweet/mid section for impulse behavior ?
Are there many commercial designs that used passive coils for timing alignment at he crossover frequencies ? Or did they just use physical offset in the tweet/mid section for impulse behavior ?
I think the modern day equivalent of a Dunlavy speaker is a Danley speaker.
Here's the polar response, frequency response and phase response of my latest speaker. I think it's in the ballpark of the Dunlavy designs.
It still needs work, but you can do some neat things with higher order filters if you physically compensate for the additional delay introduced by the xover filter.
Here's the polar response, frequency response and phase response of my latest speaker. I think it's in the ballpark of the Dunlavy designs.
It still needs work, but you can do some neat things with higher order filters if you physically compensate for the additional delay introduced by the xover filter.
Dunlavy.
I have been a fan of Dunlavy’s loudspeakers all the way back to 97?
When his SCVI was reviewed in Stereophile magazine.
It rocked the “Audiophile “ world.
Madisound has a replacement list and a new substitute listing.
All the original drivers were mostly Vifa . Their specs can still be found on line.
In later years, he was working on “Tri-amping” a 3 way design called the “Magnus”. Using 1”, 5”, and a 12”.
Flat baffle all drivers on same flat surface.
He was using an experimental digital crossover.
In my 3 way design, I use the “Mini dsp” 4x10 digital crossover.
It’s great. Everything can be set from a laptop,gain, slopes, and most importantly,
time alignement.
Good luck with your speaker.
I have been a fan of Dunlavy’s loudspeakers all the way back to 97?
When his SCVI was reviewed in Stereophile magazine.
It rocked the “Audiophile “ world.
Madisound has a replacement list and a new substitute listing.
All the original drivers were mostly Vifa . Their specs can still be found on line.
In later years, he was working on “Tri-amping” a 3 way design called the “Magnus”. Using 1”, 5”, and a 12”.
Flat baffle all drivers on same flat surface.
He was using an experimental digital crossover.
In my 3 way design, I use the “Mini dsp” 4x10 digital crossover.
It’s great. Everything can be set from a laptop,gain, slopes, and most importantly,
time alignement.
Good luck with your speaker.
Maybe the Elsinore thread is wothing the reading for the op ?
If the op has also some good souvenirs of the dunlavy sound, it should not give up the idea to stay with close (ScanSpeak equivalent , perhaps HDS Nomex if flat enough or SB Mdf) drivers and same tweeter whatever the boxing and filtering technonology : passive or active.
But for something very serious on the sound quality and soundstage sides, in the shoes of the op, I will have a look to the P-B Danle(v)y idea... totally active and indeed why not with some FIR correction at the end. Certainly a long project.
At least that's what I would do if I had the know how & savoire faire.
If the op has also some good souvenirs of the dunlavy sound, it should not give up the idea to stay with close (ScanSpeak equivalent , perhaps HDS Nomex if flat enough or SB Mdf) drivers and same tweeter whatever the boxing and filtering technonology : passive or active.
But for something very serious on the sound quality and soundstage sides, in the shoes of the op, I will have a look to the P-B Danle(v)y idea... totally active and indeed why not with some FIR correction at the end. Certainly a long project.
At least that's what I would do if I had the know how & savoire faire.
The Dunlavey used 1st order crossovers which require drivers that are inherently flat response and very wide band. You want smooth response at least 2 octaves beyond XO frequency. One thing to try is use a passive Harsch XO between the midbass and tweeter. This allows a 2nd order for tweeter to give it more protection from burning out. If you cross high like 5.5kHz, the physical setback requirement is decreased.
I would use 4x RS225-8 in series parallel (400Hz) and two PTT6.5 mid bass and a single RST28F in WG-300 waveguide (5.5kHz). I know the XO between PTT6.5 and RST28F works already.
Overall sensitivity after baffle step is about 90dB 2.83v 1m. The PTT6.5 has superb mid range clarity.
I would use 4x RS225-8 in series parallel (400Hz) and two PTT6.5 mid bass and a single RST28F in WG-300 waveguide (5.5kHz). I know the XO between PTT6.5 and RST28F works already.
Overall sensitivity after baffle step is about 90dB 2.83v 1m. The PTT6.5 has superb mid range clarity.
thoughts & question please X :
if first order, does the H5 of the RS225 not a problem as well as the little coqueterie of its high-end for the mid/tweet band (will this coqueterie low enough ? to rephrase : we need flat but also very low distorsion beyond the 2 octaves of the XO ( and some claims for almost 3 octaves) ?
Does the important offset recess of the Harsch XO will not introduce too much cabinetry offset between the mid and the tweeter, so all sort of diffraction made passively?
How 's the vertical lobbing and soundstage with a 5000 hz XO (we are very far of the theoric 1/4 WL).
Always asked myself, cause my understanding is Dunlavy was indeed applying very high crossover point between the tweeter and the mid... soundstage was fantastic from my memory !
I'm always fascinated by the easy way of electronic delay with active filtering, what a great thing, I really have to try one soon day.
if first order, does the H5 of the RS225 not a problem as well as the little coqueterie of its high-end for the mid/tweet band (will this coqueterie low enough ? to rephrase : we need flat but also very low distorsion beyond the 2 octaves of the XO ( and some claims for almost 3 octaves) ?
Does the important offset recess of the Harsch XO will not introduce too much cabinetry offset between the mid and the tweeter, so all sort of diffraction made passively?
How 's the vertical lobbing and soundstage with a 5000 hz XO (we are very far of the theoric 1/4 WL).
Always asked myself, cause my understanding is Dunlavy was indeed applying very high crossover point between the tweeter and the mid... soundstage was fantastic from my memory !
I'm always fascinated by the easy way of electronic delay with active filtering, what a great thing, I really have to try one soon day.
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I've been trying for a mtm using the cat378 morel.
With its 5.6uF, it is 6db down at 2khz, and 12db down at 1khz.
Now for a couple of 6.5" or smaller to match the 92db spl 1w/1m...………
The ptt6.5 costs how much ?
Finding drivers with a flat impedance curve also helps make the 6db crossover (woofer or midrange) much easier.
Tweeters can be tricky with 6db crossovers due to their FS that would need to be notched out unless it is 2.5-3 octaves below crossover point (I think).
With its 5.6uF, it is 6db down at 2khz, and 12db down at 1khz.
Now for a couple of 6.5" or smaller to match the 92db spl 1w/1m...………
The ptt6.5 costs how much ?
Finding drivers with a flat impedance curve also helps make the 6db crossover (woofer or midrange) much easier.
Tweeters can be tricky with 6db crossovers due to their FS that would need to be notched out unless it is 2.5-3 octaves below crossover point (I think).
...with 4 ptt6.5 you can buy a Dunlavy second hand, lol ! (you need a group buy and bought them by 10 units, it's a little Acuton priced, it will purify your wallet !)
the sb17 mfc Joe Rasmusen is using seems the ideal candidate to what you describe and cheap, perhaps a little matier as it's plastic vs paper with the old Vifa ?
the sb17 mfc Joe Rasmusen is using seems the ideal candidate to what you describe and cheap, perhaps a little matier as it's plastic vs paper with the old Vifa ?
The original SCIV used 5.5" poly cone Vifa drivers that I don't think are available but
the P17 version is:
ScanSpeak Classic P17WJ00 6.5" Woofer
Dunlavy was smart in choosing drivers with inherently flat responses in order to simplify
the crossover design. And that P17 also has a very flat response. I'm considering using
them myself.
If you must have 5.5" drivers there are classic SEAS drivers with very similar specs:
SEAS Prestige CA15RLY (H1216) 5.5" Coated Paper Cone Woofer
Madisound claims that this is the Vifa tweeter but I believe that there are better choices:
ScanSpeak Discovery D2606/9220, 1" Textile Dome Tweeter
I'd use this: SB Acoustics SB26STAC-C000-4 1" Textile Dome Tweeter
Or even better this:
SB Acoustics SB26STCN-C000-4 tweeter, 4 ohms
The schematic is here, see post #4 and note the resistors across the cap to the mids, there is very little
attenuation at LF to the mids making it a good idea to go to the P17:
Dunlavy SC IV schematics ?
the P17 version is:
ScanSpeak Classic P17WJ00 6.5" Woofer
Dunlavy was smart in choosing drivers with inherently flat responses in order to simplify
the crossover design. And that P17 also has a very flat response. I'm considering using
them myself.
If you must have 5.5" drivers there are classic SEAS drivers with very similar specs:
SEAS Prestige CA15RLY (H1216) 5.5" Coated Paper Cone Woofer
Madisound claims that this is the Vifa tweeter but I believe that there are better choices:
ScanSpeak Discovery D2606/9220, 1" Textile Dome Tweeter
I'd use this: SB Acoustics SB26STAC-C000-4 1" Textile Dome Tweeter
Or even better this:
SB Acoustics SB26STCN-C000-4 tweeter, 4 ohms
The schematic is here, see post #4 and note the resistors across the cap to the mids, there is very little
attenuation at LF to the mids making it a good idea to go to the P17:
Dunlavy SC IV schematics ?
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I can't find info about dsp SC-VI, obviously it was never finished. John Dunlavy died in 2007 and all present models are passive with analog xo Home - Duntech
I have never heard them, but I believe they are masterpieces. Large WMTMW 3-ways can't be installed in most home environments and aren't even very popular as diy projects. Narrow vertical directivity is key factor for the sound in-room I guess.
My dsp 4/3-way projects have ended with acoustic LR2 responses, without FIR. Dsp makes it easy to controur responses flat and acoustic slopes easily turn to elliptic (Duelund), which helps to reduce low end distortion and breakup modes on high end of passband. Smoother phase changes/GD seems to make acoustic instruments' sound more natural compared to 4th order system. With a 2-way speaker this is not so audible difference to me, I prefer 4th order for those.
Distortion is showing itself when I try 1st order slopes, doubling mid drivers would help. With so many overlapping drivers/slopes I guess IMD might be a problem too, especially off-axis. I gave up trying...
I have never heard them, but I believe they are masterpieces. Large WMTMW 3-ways can't be installed in most home environments and aren't even very popular as diy projects. Narrow vertical directivity is key factor for the sound in-room I guess.
My dsp 4/3-way projects have ended with acoustic LR2 responses, without FIR. Dsp makes it easy to controur responses flat and acoustic slopes easily turn to elliptic (Duelund), which helps to reduce low end distortion and breakup modes on high end of passband. Smoother phase changes/GD seems to make acoustic instruments' sound more natural compared to 4th order system. With a 2-way speaker this is not so audible difference to me, I prefer 4th order for those.
Distortion is showing itself when I try 1st order slopes, doubling mid drivers would help. With so many overlapping drivers/slopes I guess IMD might be a problem too, especially off-axis. I gave up trying...
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