Ignorance is bliss, so I must be in bliss.
I will attempt to turn a 4" and a 8" carbon fiber woofer into a 4" and 8" full range drivers.
Gjee Whizzers.
Almost reaching as high as 10khz, they just have another 10 to go.
I expect what ever I do shall suffer beaming or shouting issues, so I also plan to incorporate some sort of blocker/diffuser into the final design. I imagine a sphere or half-sphere hovering over the cone/whizzer area.
Much to my surprise the CF drivers are very dry and paper-like. There is very little resin on them. So little resin in fact that part of my design may be to add epoxy resin to either the front or back and stiffen it up. Which in turn should raise the frequency response, be it at perhaps a more jagged or peaky level.
If you want to hold your opinion until after I do things, that is fine. I do plan to experiment on a big cardboard box full of spare drivers before touching the CF drivers I actually spent money on and not found on the curb when the college students moved out of town last spring.
Anyway here is the MCM 4" and 8" carbon fiber drivers selling for what I think is a fair price. All I can say about MCM is that one of my $6 back-up tweeters I bought in case I fail at producing a super whizzer came in damaged from shipping. I called them and they are mailing me a new one - just like that.
Pictures: Yes that is a vented pole piece on the 8" driver, just like the big boys have.
8"
4"
Both
Poor little tweeter.................
I'm not sure, but I think that the light coming through the drivers is actual air hole openings in the CF weave, and not just translucent resin. I will take a close look when I have more time. Somehow this just feels wrong, I'm open to hearing your opinions on this as it could be not normal.
I hooked them up and they play, only did low levels for a few short minutes but already have some first impressions "in free air".
1. The 8" driver has a rich deep sound and nice fast bass, but I will be hard pressed into converting this into a full-range unit. Vocals are good, bass has depth, just no zing at the top end "as is".
2. The 4" driver lacks the large uncongested openness of the 8" driver but should be a breeze to convert the upper frequencies. Vocals are there, not as rich as the larger driver though.
3. I also hooked up the tweeters to test them, they are not very efficient compared to the sound levels at the same location on the volume control. It will be interesting trying to match sound levels with the mid-woofers, if I go that route as a last resort.
Link to CF drivers below (the top two), PDF's in link provide frequency response charts.
Search results for "mcm die cast woofer 55-3*"
That is all, except you might want to see the Whizzer Thread where I posted some research images and links.
http://www.diyaudio.com/forums/full-range/180690-whizzer-thread.html
I will attempt to turn a 4" and a 8" carbon fiber woofer into a 4" and 8" full range drivers.
Gjee Whizzers.
Almost reaching as high as 10khz, they just have another 10 to go.
I expect what ever I do shall suffer beaming or shouting issues, so I also plan to incorporate some sort of blocker/diffuser into the final design. I imagine a sphere or half-sphere hovering over the cone/whizzer area.
Much to my surprise the CF drivers are very dry and paper-like. There is very little resin on them. So little resin in fact that part of my design may be to add epoxy resin to either the front or back and stiffen it up. Which in turn should raise the frequency response, be it at perhaps a more jagged or peaky level.
If you want to hold your opinion until after I do things, that is fine. I do plan to experiment on a big cardboard box full of spare drivers before touching the CF drivers I actually spent money on and not found on the curb when the college students moved out of town last spring.
Anyway here is the MCM 4" and 8" carbon fiber drivers selling for what I think is a fair price. All I can say about MCM is that one of my $6 back-up tweeters I bought in case I fail at producing a super whizzer came in damaged from shipping. I called them and they are mailing me a new one - just like that.
Pictures: Yes that is a vented pole piece on the 8" driver, just like the big boys have.
8"
4"
Both
Poor little tweeter.................
I'm not sure, but I think that the light coming through the drivers is actual air hole openings in the CF weave, and not just translucent resin. I will take a close look when I have more time. Somehow this just feels wrong, I'm open to hearing your opinions on this as it could be not normal.
I hooked them up and they play, only did low levels for a few short minutes but already have some first impressions "in free air".
1. The 8" driver has a rich deep sound and nice fast bass, but I will be hard pressed into converting this into a full-range unit. Vocals are good, bass has depth, just no zing at the top end "as is".
2. The 4" driver lacks the large uncongested openness of the 8" driver but should be a breeze to convert the upper frequencies. Vocals are there, not as rich as the larger driver though.
3. I also hooked up the tweeters to test them, they are not very efficient compared to the sound levels at the same location on the volume control. It will be interesting trying to match sound levels with the mid-woofers, if I go that route as a last resort.
Link to CF drivers below (the top two), PDF's in link provide frequency response charts.
Search results for "mcm die cast woofer 55-3*"
That is all, except you might want to see the Whizzer Thread where I posted some research images and links.
http://www.diyaudio.com/forums/full-range/180690-whizzer-thread.html
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Hi!
Does that woofer have a hole in the middle?
Then remove the dustcap and poke a tweeter behind down the hole . . . and put two 3.3uF capacitors in parallel in series with the tweeter, possibly antiphase electrically to the woofer . . . and you might be surprised at the result.
Provided the crossover is gentle then you can get the sound from the two units really to coalesce in a way that's near impossible with two separate units. Two units giving same frequencies give interference patterns - but coaxially, no interference and the tweeter can simply add to the woofer and take over where the woofer falls off mechanically.
Best wishes
David P
Does that woofer have a hole in the middle?
Then remove the dustcap and poke a tweeter behind down the hole . . . and put two 3.3uF capacitors in parallel in series with the tweeter, possibly antiphase electrically to the woofer . . . and you might be surprised at the result.
Provided the crossover is gentle then you can get the sound from the two units really to coalesce in a way that's near impossible with two separate units. Two units giving same frequencies give interference patterns - but coaxially, no interference and the tweeter can simply add to the woofer and take over where the woofer falls off mechanically.
Best wishes
David P
I've seen the tiny Piezo tweeter modification in the middle of the woofer hole. I thought they used a "choke".
I'm not sure what this "choke" really is but assumed it was some sort of frequency filter filtering out the lows and not a full blown crossover.
I do not know what is behind the dust cover of either woffer driver.
I want to play with the super whizzer concept because I don't think anybody has done it with a beam blocker type diffuser in mind from the start.
I'm wondering if the voice coil inductance on the 8" driver would attenuate HF response significantly in addition to the other problems you may encounter..
As to those light spots take a small pin and use it to see if there is resin there or not, if not it will go right through, if there is it won't unless you deliberately force it. Don't..
As to those light spots take a small pin and use it to see if there is resin there or not, if not it will go right through, if there is it won't unless you deliberately force it. Don't..
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Maybe the annular ring on this vintage Goodman diffused a hot spot from the lip of that horn-like throat.
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Ãëàâíàÿ :: Site Jeen University Speakers JBL Pioneer FRS Norelco Altec Range Voice Electrostatic JansZen Jensen Electro KLH Lorenz Stentorian page Sonax Speaker Duplex Coaxial R&A comment Stephens 700 Tannoy PIM and SONIC TRU KwiKits press Audette Tw
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Ãëàâíàÿ :: Site Jeen University Speakers JBL Pioneer FRS Norelco Altec Range Voice Electrostatic JansZen Jensen Electro KLH Lorenz Stentorian page Sonax Speaker Duplex Coaxial R&A comment Stephens 700 Tannoy PIM and SONIC TRU KwiKits press Audette Tw
An externally hosted image should be here but it was not working when we last tested it.
Fun project, even if it does not end-up working, it'll be educative at least.
The coaxial tweeter trick solves the point-source problem, but then time-alignement become more important IMHO. I guess I shall see, as I'm also experimenting with drivers, putting together some coax units.
Good luck and keep us posted!
IG
The coaxial tweeter trick solves the point-source problem, but then time-alignement become more important IMHO. I guess I shall see, as I'm also experimenting with drivers, putting together some coax units.
Good luck and keep us posted!
IG
Hi
Nice experiment. FR drivers needs very light cones and loose suspensions, and woofers usually needs the opposite, seems you will need to lighten the cones and soften the suspensions and spiders.
AudioNirvana are very sensible prices, but would be interesting see a 15 inches woofer as the Eminence Alpha15A or Elegance DIPOLE-15 turn into a FR.
Good Luck, Gustavo
Nice experiment. FR drivers needs very light cones and loose suspensions, and woofers usually needs the opposite, seems you will need to lighten the cones and soften the suspensions and spiders.
AudioNirvana are very sensible prices, but would be interesting see a 15 inches woofer as the Eminence Alpha15A or Elegance DIPOLE-15 turn into a FR.
Good Luck, Gustavo
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Hi there: Have you considered that the designer of the 8-inch MCM 55-3550 carbon fiber cone speaker has used the perforated cone as a compromise to provide a suspension system with complience that varies with frequency. If so, altering (closing) the preforations may adversly affect the existing extended response of the driver. This extended range driver may respond in HF range to the addition of a wizzer and phase plug/difussor as other have done, however it does not seem to be a canidate for full range. (what is your definition of full range). ... hpoe you keep is posted, and provide listening experience....regards, Michael
Excellent point, when you change one thing it is bound to affect other things - it all works together as a system. You insights are appreciated. This is not my area of study, I'm just jumping in and having some fun.
I'm always amazed at the prices until I do the mental correction to put things in perspective.
I would post these crude experiments in the "Whizzer Thread" but I intended that thread to be more a picture posting of what others have done.
It's as easy as A-B-C as a young Michael Jackson once sang.
Comments:
A: "A" is the strainer screen form the dollar store 2-part plastic epoxied on. Yes, I get more highs but not a huge amount and there is a slight canning affect.
B: "B" is the tall open top cone made of craft store brass which might not be real brass. It is the stuff you press down on to get embossed reliefs. More highs than the screen, plus it seems to clean up the sound of the speaker. The sound out of the cone beams straight out and can be deflected by a sphere, and the off axis sound is much better balanced than I expected.
C: "C" is the driver still hooked up to a choked tweeter (16 ohm Panasonic on the back listing). This was good to do with a tweeter hooked up because I could directly compare the sound out the the crown looking whizzer to the sound coming out the the tweeter. They were similar but the whizzzer actually sounded cleaner and more extended than the tweeter close up. The wavy crown top shape comes out of my hovercraft project where I made the splitter wavy. I succeeded in breaking up sound nodes and made the craft more quieter (half as noisy now). To do this on a whizzer was to knock down any single frequency beaming. The sound is directional, but like the open top cone model really good off axis, better than the original driver in fact. The original driver is rather horn like sounding with it's deep fluted shape. So far this is my favorite configuration, but not my last, not by a long shot. I have not made a "Super Whizzer", only a whizzer. A "Super Whizzer" by my definition is equal to a tweeter and maybe even a super-tweeter's performance.
What's Next?
1. I have to do a version of a traditional whizzer to get a baseline comparison.
2. I still want to play with fine brass screen mesh material, they don't carry it at the craft stores anymore, so I'll have to order some off the Internet.
3. I've had some fun but need to get some projects out the door and make some money. I'll post later when I have the time to resume this experiment.
PS: No measurements, because I trust my ears.
It's as easy as A-B-C as a young Michael Jackson once sang.
Comments:
A: "A" is the strainer screen form the dollar store 2-part plastic epoxied on. Yes, I get more highs but not a huge amount and there is a slight canning affect.
B: "B" is the tall open top cone made of craft store brass which might not be real brass. It is the stuff you press down on to get embossed reliefs. More highs than the screen, plus it seems to clean up the sound of the speaker. The sound out of the cone beams straight out and can be deflected by a sphere, and the off axis sound is much better balanced than I expected.
C: "C" is the driver still hooked up to a choked tweeter (16 ohm Panasonic on the back listing). This was good to do with a tweeter hooked up because I could directly compare the sound out the the crown looking whizzer to the sound coming out the the tweeter. They were similar but the whizzzer actually sounded cleaner and more extended than the tweeter close up. The wavy crown top shape comes out of my hovercraft project where I made the splitter wavy. I succeeded in breaking up sound nodes and made the craft more quieter (half as noisy now). To do this on a whizzer was to knock down any single frequency beaming. The sound is directional, but like the open top cone model really good off axis, better than the original driver in fact. The original driver is rather horn like sounding with it's deep fluted shape. So far this is my favorite configuration, but not my last, not by a long shot. I have not made a "Super Whizzer", only a whizzer. A "Super Whizzer" by my definition is equal to a tweeter and maybe even a super-tweeter's performance.
What's Next?
1. I have to do a version of a traditional whizzer to get a baseline comparison.
2. I still want to play with fine brass screen mesh material, they don't carry it at the craft stores anymore, so I'll have to order some off the Internet.
3. I've had some fun but need to get some projects out the door and make some money. I'll post later when I have the time to resume this experiment.
PS: No measurements, because I trust my ears.
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I have four of these from around 1988, three of them might get "whizzered", although I should experiment on more junk from the recycle store first.
http://s184.photobucket.com/albums/x295/kach22i/Stereo/
http://s184.photobucket.com/albums/x295/kach22i/Stereo/
Last weeks whizzers.............................
Modified, this weeks whizzers...........................
I have one developed out of this (not posted), one with little parts of everything more or less which I've mounted to my largest scarp driver for further development.
I could tell you which ones do what and how they sound. However if you really want to have some fun you will build your own and find out for yourself.
Because these drivers were in storage for over 20 years or found on the side of the road this spring, I'd estimate that the glues, brass and other materials set me back about the cost of a fill up of gas in my S-10 or vintage Porsche.
100 years ago some guy did the same thing before the mold of whizzer design was cast. They had more fun than the guys doing it on a computer these days - just my opinion.
Sorry no measurements, I'm trusting my ears on this one. I will say that the two-way in the line-up which I added the stove pipe to keeps kicking the one way full range whizzers ****. I'm still hoping to change this and feel there is still a slight chance of pulling it off.
Modified, this weeks whizzers...........................
I have one developed out of this (not posted), one with little parts of everything more or less which I've mounted to my largest scarp driver for further development.
I could tell you which ones do what and how they sound. However if you really want to have some fun you will build your own and find out for yourself.
Because these drivers were in storage for over 20 years or found on the side of the road this spring, I'd estimate that the glues, brass and other materials set me back about the cost of a fill up of gas in my S-10 or vintage Porsche.
100 years ago some guy did the same thing before the mold of whizzer design was cast. They had more fun than the guys doing it on a computer these days - just my opinion.
Sorry no measurements, I'm trusting my ears on this one. I will say that the two-way in the line-up which I added the stove pipe to keeps kicking the one way full range whizzers ****. I'm still hoping to change this and feel there is still a slight chance of pulling it off.
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I'm making some progress, the latest effort is not shouty and has some fair highs but the mid-range vocals are a little recessed. Not a bad balance just not as efficient or dynamic as I would like. Therefore I'm considering some alternatives and one of those alternatives includes making my plastic dust cap cover more stiff to increase the highs.
Has everyone seen this?
Accuton Loudspeakers from Madisound
What if I brushed on some epoxy to the plastic dust cap and sprinkled some metal or ceramic powder on it?
Link:
Lifecasting, Mold Making, Molding Materials, and Casting Materials from EnvironMolds
I'm sure someone has tried this. .....or not.
So what was the long term results of all the heat and vibration in a loudspeaker environment? More importantly was the result pleasing sound wise?
I don't want to buy a pound of metal dust to find out, but may experiment on what ever I come up with first which is cheap to play with.
I've considered gold leaf from the craft store, but think it would just flake off. Besides all that glue and soft gold may just add mass and not make it any stiffer.
Has everyone seen this?
Accuton Loudspeakers from Madisound
What if I brushed on some epoxy to the plastic dust cap and sprinkled some metal or ceramic powder on it?
Link:
Lifecasting, Mold Making, Molding Materials, and Casting Materials from EnvironMolds
I'm sure someone has tried this.
.....or not. So what was the long term results of all the heat and vibration in a loudspeaker environment? More importantly was the result pleasing sound wise?
I don't want to buy a pound of metal dust to find out, but may experiment on what ever I come up with first which is cheap to play with.
I've considered gold leaf from the craft store, but think it would just flake off. Besides all that glue and soft gold may just add mass and not make it any stiffer.
"Sorry no measurements, I'm trusting my ears on this one."
nothing against that, but fr response measurement is something you can objectively have for different speakers and different whizzers, and easy store in the computer, overlay, compare, share, post...and so on
what you say about sound is quite irrelevant to others
plus, you can not objectively remember the sound of one modification few days later, its not possible to remember the sound, yet its easy to store fr response plots
I use holm impulse from holm acoustic web, great free software
ed
nothing against that, but fr response measurement is something you can objectively have for different speakers and different whizzers, and easy store in the computer, overlay, compare, share, post...and so on
what you say about sound is quite irrelevant to others
plus, you can not objectively remember the sound of one modification few days later, its not possible to remember the sound, yet its easy to store fr response plots
I use holm impulse from holm acoustic web, great free software
ed
Thanks for the lead, I'll look into it.
Right now I think that I've added too much mass.
All of the whizzers I've posted shout compared what I'm working on now. I've just swung too far in one direction and need to swing it back a bit.
In the end I might not be able to beat just adding a tweeter, but it's about the journey, right?
Any "whizzer" not made from a very light material will reduce the overall high frequency output aside from resonant spikes which add un-natural coloration to the sound.
I'm willing to bet that there IS some kind of glue/resin filling the holes between the weave on your carbon fiber woofers. See if you can't blow through the cone if you press your lips onto it.
I'm willing to bet that there IS some kind of glue/resin filling the holes between the weave on your carbon fiber woofers. See if you can't blow through the cone if you press your lips onto it.
I'd suspect that with wideband drivers as small as the RS pictured,( or those in your experiments if other) the effective moving mass of additional material shown on some of the more elaborate "whizzers" could equal or exceed that for which the motor was designed.
They'll still move air of course, but most likely with substantially reduced output, limited excursion and very interesting tonal balance, resonance and dispersion patterns.
From my personal experience, many of the 3-4" widebanders of this class don't particularly need help in this area.
They'll still move air of course, but most likely with substantially reduced output, limited excursion and very interesting tonal balance, resonance and dispersion patterns.
From my personal experience, many of the 3-4" widebanders of this class don't particularly need help in this area.
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Do they have to be passive?
If you want to make them with in-board amplification, the technique of putting a current sensing resistor in one of the speaker lines, and using that to provide positive feedback to the power amp, can provide a big extension to the frequency response, like 22kHz from an ordinary 8-inch.
If you want to make them with in-board amplification, the technique of putting a current sensing resistor in one of the speaker lines, and using that to provide positive feedback to the power amp, can provide a big extension to the frequency response, like 22kHz from an ordinary 8-inch.
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