Love to have some advice on dispersion. My wife loves the old console that I grew up with in the seventies (although no longer sporting the delightful free-standing 8-track deck). She likes the retro look.
Right now, it is incredibly muffled-sounding, as the caps and paper drivers are (only slightly) older than I am. So, that's one job.
But I really want to punch it up a notch with the closest approximation to great speakers that this thing can field (within a certain budget, naturally). Having drivers firing at the knee caps certainly hinders the quality of the audio reproduction...as likely does these odd foam boxes.
I suppose my design goal doesn't include the ultimate clinical listening experience--I sit in front of studio monitors almost everyday I'm not traveling--so I just want a nice, even, room-filling, and effortless sound (when paired with a sub). But because of the weirdness of it all, this presents a challenge. Especially when confronted by the smallish dimensions of the available opening.
Three directions immediately spring to mind. Most require building at least part of box inside the cabinet. Any thoughts on which would end up best?
An externally hosted image should be here but it was not working when we last tested it.
Right now, it is incredibly muffled-sounding, as the caps and paper drivers are (only slightly) older than I am. So, that's one job.
But I really want to punch it up a notch with the closest approximation to great speakers that this thing can field (within a certain budget, naturally). Having drivers firing at the knee caps certainly hinders the quality of the audio reproduction...as likely does these odd foam boxes.
An externally hosted image should be here but it was not working when we last tested it.
I suppose my design goal doesn't include the ultimate clinical listening experience--I sit in front of studio monitors almost everyday I'm not traveling--so I just want a nice, even, room-filling, and effortless sound (when paired with a sub). But because of the weirdness of it all, this presents a challenge. Especially when confronted by the smallish dimensions of the available opening.
An externally hosted image should be here but it was not working when we last tested it.
Three directions immediately spring to mind. Most require building at least part of box inside the cabinet. Any thoughts on which would end up best?
- MTM - But maybe the tweet canted up at a small angle to assist dispersion?
- Dipole - Open up the three sides on each end with nothing but grille...
- OEM - Put two woofers in each side and a horn pointing forward as originally designed.
I'd suggest finding a small bookshelf cabinet design you like and simply put it in the console, angled up to your listening position.
I have a pair of full range 8" in Karlson cabinets that already have an up angle I'd sell cheap, they actually measure fairly decent using Smaart, and have a good "retro" sound.
If you have any interest, I'll measure the size and see if they would drop in.
By the way, I grew up with both the Magnavox and the Karlsons my dad built circa 1961, the Karlson sounded way better than the goofy Magnavox side fireing woofer and front mounted Heppner horn!
Art Welter
I have a pair of full range 8" in Karlson cabinets that already have an up angle I'd sell cheap, they actually measure fairly decent using Smaart, and have a good "retro" sound.
If you have any interest, I'll measure the size and see if they would drop in.
By the way, I grew up with both the Magnavox and the Karlsons my dad built circa 1961, the Karlson sounded way better than the goofy Magnavox side fireing woofer and front mounted Heppner horn!
Art Welter
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don't do a mtm on the floor.
You could make speakers that sit on it or next to it, but that would ruin the looks.
Not many speaker designs sound good when firing straight ahead sitting on the floor (beign above the main axis). But a 2 way would be better than an mtm.
You could use full range drivers that have an increasing high end (such as a fostex fe206e). They measure flatter off axis (you standing) due to their size (greater than 6.5"). But the 206e would have zero bass in an open baffle.
And / or leave the back off, add some foam, and use it as an open backed cabinet (like most were).
Norman
You could make speakers that sit on it or next to it, but that would ruin the looks.
Not many speaker designs sound good when firing straight ahead sitting on the floor (beign above the main axis). But a 2 way would be better than an mtm.
You could use full range drivers that have an increasing high end (such as a fostex fe206e). They measure flatter off axis (you standing) due to their size (greater than 6.5"). But the 206e would have zero bass in an open baffle.
And / or leave the back off, add some foam, and use it as an open backed cabinet (like most were).
Norman
Well, that's essentially my plan. Except, I do want the fun of actually building the loudspeaker system directly into the cabinet.
So, that's one vote for full range--which I hadn't truly considered. I have no experience with FR. High end worries me there--just in general. Particularly so near the floor, but I'll be honest, that's purely a gut reaction not a considered opinion. So, let me give it some thought.
I'll bet! Thanks for the reply, Art!
Wow! That looks great!
Can you provide a drawing of the singing furniture?
I would definitely go for a three way open baffle.
Even an 8 inch wide range driver does not have to be angled towards the listener up until 1000-1500-2000 hz, this opens the way for Fane and Eminence 5 to 8 inch midranges. Those are known to go pretty flat up to 5 Khz and more.
Then you can have a tweeter tilted up and a 12 or 15 inch OB bass drivers on the sides of the thing.
Having in mind that the console has a back plate of some kind, this could be simulated as an U-frame with damped rear chamber (you will add damping inside).
It isn't an issue that the openings are a little shy of 15 inches, as we lately understood, restricting some of the cone area is only beneficial as it lowers Fs and rises impact energy of the output.
The only issue I see is the woofer pressure modulating the midrange if the back is not open enough.
The best part is that it can be cheap and ugly on the inside since it is so beautiful outside
I'm excited!
Can you provide a drawing of the singing furniture?
I would definitely go for a three way open baffle.
Even an 8 inch wide range driver does not have to be angled towards the listener up until 1000-1500-2000 hz, this opens the way for Fane and Eminence 5 to 8 inch midranges. Those are known to go pretty flat up to 5 Khz and more.
Then you can have a tweeter tilted up and a 12 or 15 inch OB bass drivers on the sides of the thing.
Having in mind that the console has a back plate of some kind, this could be simulated as an U-frame with damped rear chamber (you will add damping inside).
It isn't an issue that the openings are a little shy of 15 inches, as we lately understood, restricting some of the cone area is only beneficial as it lowers Fs and rises impact energy of the output.
The only issue I see is the woofer pressure modulating the midrange if the back is not open enough.
The best part is that it can be cheap and ugly on the inside since it is so beautiful outside
I'm excited!
OK. I planned to kick the baffle back at a small angle rather than exactly perpendicular to the floor. Does that alter your thoughts in any way? (I'll knock together a quick sketchup diagram.)
My thoughts behind the MTM were really more like an TM+M (if that's even a thing
). Because of the overall size available in the grille, I imagined dividing up the surface area would offer more flexibility in placement. But that may just be wrong-headed.My goal isn't necessarily audiophile sound in any one sweet spot, it's good room-filling and articulate sound.
Two votes for full range. I had not anticipated that.
Thanks for the reply, Norman!
welcome, I'm always happy to express my opinion on everyone !!!! lol !!!!
Room filling sound = wide dispersion
Full range driver will be more intelligibile but it is a trade-off. Sometimes I need a bit more oomph than a pair of 4" can give me.
Yea, a 2-way with baffle step, but you probably don't need it because it is close to the wall and on the floor.
If you want a nice floppy qts driver, try the betsy driver from wild burro. It would work well mounted to the face but maybe aimed up a bit. You may need a bit of hf boost for a bit of off axis listening.
But good luck !!!!!!!!!!
and keep us updated !!!!!!!!
Norman
Room filling sound = wide dispersion
Full range driver will be more intelligibile but it is a trade-off. Sometimes I need a bit more oomph than a pair of 4" can give me.
Yea, a 2-way with baffle step, but you probably don't need it because it is close to the wall and on the floor.
If you want a nice floppy qts driver, try the betsy driver from wild burro. It would work well mounted to the face but maybe aimed up a bit. You may need a bit of hf boost for a bit of off axis listening.
But good luck !!!!!!!!!!
and keep us updated !!!!!!!!
Norman
Count my vote for selling the Karlsons, not for full range ;^).Two votes for full range. I had not anticipated that.
Thanks for the reply, Norman!
That said, by bookshelf I was more thinking along the lines of a small 2-way or co-ax.
If you are not using the record storage bin in the center of the Magnovox, there is plenty of room for a sub, so the top speakers don't need to carry a lot of weight.
Here was my favorite sounding speaker system until I sold my sailboat:
Seas P 17 Coax with Vifa bass assist cone:
+ -----RP1-----C1----------C2----------- +
---------------------------L1---------RP2--- CoaxTweeter
- -------------------------------------------- -
C1 = 3 uf
C2 = 7 uf
L1 = .43 mH
RP1 = 2 Ohm
Rp2 = 13 Ohm
______________________________________________
+ ------L1----------------------------------- +
-----------------C1-------CJ-------------------Coax
---------------------------- RJ-------------------Woofer
- -------------------------------------------- -
L1 = .36 mH
C1 = 16 uf
CJ = 39 uf
RJ = 8 Ohm
______________________________________________
+-------L1--------------------------------- +
------------------------C1-------------------bass assist cone
- ------------------------------------------ -
L1 = 13.5 mH
C1 = 120 uf
or
L1 = 9.5 mH
C1 = 170 uf I think I went with this choice, good chokes get real expensive, and the bypass cap is not very critical.
Cabinet and crossover were designed by Bob Oswood.
The P 17 coax goes in a .4 cubic foot box tuned to 45 HZ, a port 6 square inches, 12 inch deep.
The Vifa woofer (bass assist cone), the model number which has escaped me, goes in a 1 cubic foot box tuned to 37.5 HZ, a port 8 square inches, 11.2 inches deep.
These ports are rather large, and the area they take up is added to the box volume, as are the cone displacement. Fiberglass insulation was put on two sides of the interior.
Don't know if those cones are still available, if not I also have some tweeters that could be added to the Karlson...
Art
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Here's one version of the idea clanging around inside my skull. I needed to teach myself Sketchup, anyway, so might as well use it here. And while spending my day listening to conference calls, I found plenty of opportunity.
This allows for a 12.5 degree angle, a 6" or so full-range, and a traditional piezo tweeter. I drew a complete enclosure with slightly less than 17 cu. inches (intrusion of the baffle). The 12.5 is pure guesstimation, BTW, may end up a bit steep.
So, I could leave an open back...and even the end, if required. I don't know enough about transmission lines or quarter waves to even make an attempt at sounding intelligent, but looking down into the box, I wonder if it would be worth while to try to chop it up and vent out the end (mirrored on the other side)? I'll have to read up on it.
Thanks for the replies to all, and please keep them coming. I'm just conversant enough to be truly dangerous.
An externally hosted image should be here but it was not working when we last tested it.
This allows for a 12.5 degree angle, a 6" or so full-range, and a traditional piezo tweeter. I drew a complete enclosure with slightly less than 17 cu. inches (intrusion of the baffle). The 12.5 is pure guesstimation, BTW, may end up a bit steep.
An externally hosted image should be here but it was not working when we last tested it.
So, I could leave an open back...and even the end, if required. I don't know enough about transmission lines or quarter waves to even make an attempt at sounding intelligent, but looking down into the box, I wonder if it would be worth while to try to chop it up and vent out the end (mirrored on the other side)? I'll have to read up on it.
An externally hosted image should be here but it was not working when we last tested it.
Thanks for the replies to all, and please keep them coming. I'm just conversant enough to be truly dangerous.
Ah, gotcha. And I hadn't considered coax yet. I always think of the big Tannoys that I loved back in the 24-track analog studio days when I hear "coax".
Already had the same thought.
I'll look into that. So, I'm taking it that you'd suggest a coax setup rather than full-range plus tweeter?
Thanks again.
That cavity looks suspicious to me. It could induce all kinds of artefacts in the sound.
You could avoid it by using the bass/midrange driver only up to the point in frequency where it no longer emits in the full front hemisphere and then crossover to a HF or wide range driver that will inevitably beam at higher frequencies.
You could tilt only the HF driver and leave the baffle vertical.
Or you should fill the cavity heavily with sound absorbing, but that is too much complication since you can avoid it with simple planning.
There are enough 8 inch drivers that go past 1 kHz with 180 degree emission.
It should be as simple as possible. So what about a guitar low Fs driver and a cheap HF horn that goes down to 1 kHz? Why build enclosure when there are so many beautifully voiced cheap high Qts drivers suitable for OB and the likes?
Which driver goes above and which below is a matter of simulation of the crossover after the drivers are chosen. The lagging (by phase) driver goes above and the leading below. Thus an upwards beaming parallel to the axis of the tilted driver could be achieved in the crossover region.
Best regards!
You could avoid it by using the bass/midrange driver only up to the point in frequency where it no longer emits in the full front hemisphere and then crossover to a HF or wide range driver that will inevitably beam at higher frequencies.
You could tilt only the HF driver and leave the baffle vertical.
Or you should fill the cavity heavily with sound absorbing, but that is too much complication since you can avoid it with simple planning.
There are enough 8 inch drivers that go past 1 kHz with 180 degree emission.
It should be as simple as possible. So what about a guitar low Fs driver and a cheap HF horn that goes down to 1 kHz? Why build enclosure when there are so many beautifully voiced cheap high Qts drivers suitable for OB and the likes?
Which driver goes above and which below is a matter of simulation of the crossover after the drivers are chosen. The lagging (by phase) driver goes above and the leading below. Thus an upwards beaming parallel to the axis of the tilted driver could be achieved in the crossover region.
Best regards!
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If I ever start another garage band, that's the new name.Wow! That looks great!
Can you provide a drawing of the singing furniture?
Interesting. What do you think about using an 8 flat on the front with angle tweeter (as you say), and then a single dvc sub in the center? It would certainly be simple enough to build--only a sidewall to separate the subwoofer chamber.
The back is a thin "peg board" type material. Basically held on with a few screws and ventilated with half-inch holes. I figured to either use it whole if I build boxes inside, or cut it out for grilles if using "open" baffle.
How did you envision the damping in this case? Or do you mean attach damping TO the inside back of the console?
OK, I guess my question is, would you do this in ADDITION to a sub? (I'll post a picture of the middle section I planned to modify for a down-firing box.)
I think I can get it pretty open. Probably just mount cloth directly to the openings...somehow. I'll snap a picture of it.
Well, it certainly is "something", anywayThe best part is that it can be cheap and ugly on the inside since it is so beautiful outside
I'm excited!
It certainly isn't the way I'd build a great audio system, but it IS fun and retro. When we brought it home a few weeks ago I was hit by a palpable wave of nostalgia when I saw the back-lit tuner dial in the dark. I felt like I was five years old again. People say that kind of thing all the time, but I almost had to sit down.I think you're selling me on the idea. I love the simplicity of it.
With no box inside the ends, I can use the arch in the cabinet for the tweeter at any particular angle. Might even be able to place it on a piano-hinge and make it adjustable.
Were you thinking consumer-class or professional for the horn? Foster makes one that looks VERY attractive in price that does all way to 1 kHz. It is a wide dispersion (3x7)...there are constant directivity horns as well, but with the up angle, I'm not sure I need them. And I would have to countersink to keep the buttocks out of the grille.
EDIT: Just noticed that those Foster horns only go up to 18000...most of the others hold a range from 1500 to 30000.
(Man, if I had a nickle for everything I said that...)
Sounds like more research for me. You wouldn't happen to have a link that would help me out with the concept of lagging...you've found one of the many gaps in my knowledge.
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Sources in the vast majority will be FLAC, MP3, and Rhapsody via custom DAC. I will probably revamp the turntable just to make sure it works, but I'll probably never use it.
I imagine amplification configured as needed, but firmly in the solid state world. Custom amps, kits, or whatever works, but with active crossovers. That is unless the final setup is so obvious that coming down firmly on a particular passive xover makes sense. And it may NEVER make sense, as this thing is always pushed up against a wall and moved to different locations constantly with the furniture.
One thing's certain, it will never be in the optimal source position in any room it might visit.
The goal is to have fun rebuilding a retro 60's oddity (the console stereo). I want to spend as little as possible (naturally) while trying to make the audio articulate and widely dispersed throughout the room. Since the cabinet itself constrains many of the choices, I decided to start with the drivers and configuration there rather than the other way round.
So, therefore, power and impedance choices follow the final speaker design. Save for a subwoofer plate amp for the pure KISS of it. To finish up, I'll rebuild the tuner and eq circuits (new caps, etc.) and tap in before the power stage of the original system.
Thanks for the reply and the questions! Sure, it's a Frankensteinian monster, but an off-beat and wacky one.
This is the center of the cabinet for any interested. And yes, those things on the floor are, I believe, the simple filters the console uses as the only xover. I'm pretty sure the plastic album bin will snap out easily and leave room for a sub. The main circuit board hangs down on the left side, but I think I can figure that out.
An externally hosted image should be here but it was not working when we last tested it.
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Hi,
Well one option is a high power DC supply and to use car amplifiers with
built in active crossover functions depending on what your really after,
or car amps with graphic EQ can also be useful. Its a useful approach
for jukeboxes or games cabinets with lots of different drivers.
I'm certain the polystyrene sections are not original and probably don't help.
Side firing bass units and forward horns are not a bad idea in principle.
Are the horns still working properly ?
http://www.diyaudio.com/forums/multi-way/207530-vintage-style-stereo-console-design.html
Is a thread where I discuss a miles better alternative to an MTM,
and probably the best quality alternative of all your likely to find,
for a room filling wide dispersion sound at seated ear height.
T/M/B on the front, 0.5 B on the side, well braced boxes.
rgds, sreten.
Well one option is a high power DC supply and to use car amplifiers with
built in active crossover functions depending on what your really after,
or car amps with graphic EQ can also be useful. Its a useful approach
for jukeboxes or games cabinets with lots of different drivers.
I'm certain the polystyrene sections are not original and probably don't help.
Side firing bass units and forward horns are not a bad idea in principle.
Are the horns still working properly ?
http://www.diyaudio.com/forums/multi-way/207530-vintage-style-stereo-console-design.html
Is a thread where I discuss a miles better alternative to an MTM,
and probably the best quality alternative of all your likely to find,
for a room filling wide dispersion sound at seated ear height.
T/M/B on the front, 0.5 B on the side, well braced boxes.
rgds, sreten.
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I'd rather you would buy my full range Karlsons and a pair of tweeters from me, but the Seas coax with helper subs sound better, and have wider dispersion and frequency range.
Getting the crossover right is what really makes a difference between "so-so" and great sounding speakers, if you don't plan on going active or getting a measurement set up it is best to go with a proven design like the one I suggested.
Sreten,
I spent many nights in my youth listening to a Magnovox console much like the one pictured,my head between the horns, thought it was a great experience. Can still remember a radio program with Jimi Hendrix live, lots of mind-blowing panned effects, never have heard the same version again.
As an adult, after hearing what good sound was all about, when my parents decided to get rid of the console, I turned it on again.
It was laughable in terms of frequency response, imaging, and output before gross distortion.
Believe me, if the Heppner horns work, they still won't be "proper"
.Art
It was laughable in terms of frequency response, imaging, and output before gross distortion.
Believe me, if the Heppner horns work, they still won't be "proper"
Art
Hi,
Fair enough. Just wondering about the "muffled" sound.
I've heard some dreadful old valve stuff, but if you can forget about
real bass and treble, imaging and high output, also some nice stuff.
rgds, sreten.
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