Hi,
This is currently more of a thought exercise on designing and building cabinets for full range speakers.
I don't have a specific driver in mind... and my questions are pretty basic.
I was looking at the Fyne F1-8s (8" coax) in a compact 'bookshelf' speaker. (Their F1-5s are the same design in a smaller package and are bookshelf speakers)
They have a downward ported base, and I think I know how I can do that... Its the cabinet itself that I need to focus on...
I want to CNC the cabinet in layers. I can calculate the number of layer and use either MDF / Plywood, or a mix of both.
My first question is shape. While the Fyne's have the driver in a cylindrical shape protruding from the cabinet, the cabinet is also shaped a bit like a tear drop.
Now does the internal shape matter? I mean I could design the speaker to have the internal walls follow the same contour or be a box inside. (So side walls would be thicker.) This would reduce the need for internal bracing. Or I could make it where I follow the contour, and then do internal bracing...
(The bracing opens up some other questions in term of creating box tubes... ) In terms of ports, I plan on 3D printing.
The other thing I am curious about is dimensions. It seems that w CoAx or full range drivers, the rule of thumb is that the cabinet should be 2x the diameter?
(e.g an 8" driver has a cabinet depth of 16". )
Again this is just a thought exercise. (For now) If I go w a smaller speaker driver, will have to pair it w a small powered sub.
And other thoughts... Two listening rooms. My office (11x13) ish or the main room (living/dining combo) 17x40 ish.
All types of music... and not very loud.
Also just to add.
One of my nephews is a Mech E and I plan on bribing him for his help w the cad drawings and what not.
Any and all input is appreciated.
This is currently more of a thought exercise on designing and building cabinets for full range speakers.
I don't have a specific driver in mind... and my questions are pretty basic.
I was looking at the Fyne F1-8s (8" coax) in a compact 'bookshelf' speaker. (Their F1-5s are the same design in a smaller package and are bookshelf speakers)
They have a downward ported base, and I think I know how I can do that... Its the cabinet itself that I need to focus on...
I want to CNC the cabinet in layers. I can calculate the number of layer and use either MDF / Plywood, or a mix of both.
My first question is shape. While the Fyne's have the driver in a cylindrical shape protruding from the cabinet, the cabinet is also shaped a bit like a tear drop.
Now does the internal shape matter? I mean I could design the speaker to have the internal walls follow the same contour or be a box inside. (So side walls would be thicker.) This would reduce the need for internal bracing. Or I could make it where I follow the contour, and then do internal bracing...
(The bracing opens up some other questions in term of creating box tubes... ) In terms of ports, I plan on 3D printing.
The other thing I am curious about is dimensions. It seems that w CoAx or full range drivers, the rule of thumb is that the cabinet should be 2x the diameter?
(e.g an 8" driver has a cabinet depth of 16". )
Again this is just a thought exercise. (For now) If I go w a smaller speaker driver, will have to pair it w a small powered sub.
And other thoughts... Two listening rooms. My office (11x13) ish or the main room (living/dining combo) 17x40 ish.
All types of music... and not very loud.
Also just to add.
One of my nephews is a Mech E and I plan on bribing him for his help w the cad drawings and what not.
Any and all input is appreciated.
Translam? A huge waste. The only thing it gets you are more exotic shapes.
Takes way more material to end up with a lower performance enclosure.
Not awhole lot. Outer shape will largely dictate the diffration signature.
That gets you nowhere. Fs, Vas, Qts are largely what determines cabinet size.
The cylinder holding the driver in this one is really good at making for an ugly diffraction signature. The firstthing that struck me with the Fynns, was this, i’m guessing, someone in the marketing department.
A translam probably need sto be twice as thick as if the material was used in the direction it was designed to be used, and due to the slices more bracing is probably required. I have yet to see a translam that approaches bracing in a decent manner.
That is the way to get exotic shapes.
dave
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@Dave,
Thanks for the quick response.
I was thinking translam because of the interesting shapes.
I mean you could do a box, double the thickness of the walls, and then use a CNC to shape the wall.
(That would be one way to do it. and maybe do a translam for the back wall as a solid piece. )
I'm just working thru it. W MDF, you don't have a direction to the panel.
It could be that because I'm looking at a large driver (8") for a book shelf ( less than 24" tall) that must have a certain number of liters of space that I see deeper cabinets.
I was trying to use the DYI Speaker Box calculator: https://www.diyaudioandvideo.com/Calculator/SpeakerBoxEnclosure/
For:
https://www.madisoundspeakerstore.c...as-exotic-x1-08-f8-8-ohm-8-full-range-driver/
(Note: I also checked w Seas's website and changed the numbers a bit to match.)
I'm at a loss on the Qtc and just plugged in .707
So the box says 62 liters If I did a cabinet matching the Fyne F1-8 (Not the S which is taller, that was a plural s) ... and I calc the volume of the box...
I'm somewhere around 45L.
Also the port length is a negative number while the width is 3" ???
(So I know its me. )
Also I know that if I choose a different speaker.. I will get different values.
So what happens if you build too small a box?
I mean I pulled up the Seas Exotic as a over the top driver
I know that there is TangBang, Dayton Audio, etc... so right now not tied to anything.
Ok...
So Fyne has this F1 as their 'Flagship reference model' and then they make other series that are not as shaped.
Now I know to take the reviews from YouTube audiophiles with a grain of salt, but they seem to be extremely positive.
(If they sounded like carp [sic] then how could they get ~11K a pair?
It looks like the edge of the cone is further out than the baffle?
(Again I'm still learning about the front baffle and designs..)
Thx again... this is a learning process for me.
On a separate note... the downward port is interesting.
It looks like they have two aluminum plates separated by the three cylinders and then the front two have plastic "wave guides" (for a lack of a better term, and then their cone in the center attached to the base plate, protruding up in to the upper plate and into the port tube. Then the back is closed off where the speaker post connection plate is located. (So air moves to the side and front. ) Thought that kinda smart.
Thanks for the quick response.
I was thinking translam because of the interesting shapes.
I mean you could do a box, double the thickness of the walls, and then use a CNC to shape the wall.
(That would be one way to do it. and maybe do a translam for the back wall as a solid piece. )
I'm just working thru it. W MDF, you don't have a direction to the panel.
Doesn't this determine the volume?
It could be that because I'm looking at a large driver (8") for a book shelf ( less than 24" tall) that must have a certain number of liters of space that I see deeper cabinets.
I was trying to use the DYI Speaker Box calculator: https://www.diyaudioandvideo.com/Calculator/SpeakerBoxEnclosure/
For:
https://www.madisoundspeakerstore.c...as-exotic-x1-08-f8-8-ohm-8-full-range-driver/
(Note: I also checked w Seas's website and changed the numbers a bit to match.)
I'm at a loss on the Qtc and just plugged in .707
So the box says 62 liters If I did a cabinet matching the Fyne F1-8 (Not the S which is taller, that was a plural s) ... and I calc the volume of the box...
I'm somewhere around 45L.
Also the port length is a negative number while the width is 3" ???
(So I know its me. )
Also I know that if I choose a different speaker.. I will get different values.
So what happens if you build too small a box?
I mean I pulled up the Seas Exotic as a over the top driver
I know that there is TangBang, Dayton Audio, etc... so right now not tied to anything.
Ok...
So Fyne has this F1 as their 'Flagship reference model' and then they make other series that are not as shaped.
Now I know to take the reviews from YouTube audiophiles with a grain of salt, but they seem to be extremely positive.
(If they sounded like carp [sic] then how could they get ~11K a pair?
It looks like the edge of the cone is further out than the baffle?
(Again I'm still learning about the front baffle and designs..)
Thx again... this is a learning process for me.
On a separate note... the downward port is interesting.
It looks like they have two aluminum plates separated by the three cylinders and then the front two have plastic "wave guides" (for a lack of a better term, and then their cone in the center attached to the base plate, protruding up in to the upper plate and into the port tube. Then the back is closed off where the speaker post connection plate is located. (So air moves to the side and front. ) Thought that kinda smart.
Qtc is for sealed, otherwise leave blank and input T/S specs.
Too small = over-damped, ergo too big = under-damped.
'Sound is round', so try to visualize a sound frequency 'bubble' vibrating back n' forth at the speed of sound (~1128 ft_sec) over a very rounded edge that doesn't deform it Vs a very sharp one that distorts it, creating an eddying bandwidth (BW) of higher frequencies.
Anything but an accurate reproduction, but due to the way we hear it can make for a more euphonic sounding speaker, so likely the reason for the design and with the round base that allows all the BW below the driver's effective diameter BW, further emphasizes this euphonic distortion.
Too small = over-damped, ergo too big = under-damped.
'Sound is round', so try to visualize a sound frequency 'bubble' vibrating back n' forth at the speed of sound (~1128 ft_sec) over a very rounded edge that doesn't deform it Vs a very sharp one that distorts it, creating an eddying bandwidth (BW) of higher frequencies.
Anything but an accurate reproduction, but due to the way we hear it can make for a more euphonic sounding speaker, so likely the reason for the design and with the round base that allows all the BW below the driver's effective diameter BW, further emphasizes this euphonic distortion.
That is frequency dependent.
Following the baffle visually doesn't always make sense when following the wavefronts will show you the baffle situation.
Following the baffle visually doesn't always make sense when following the wavefronts will show you the baffle situation.
You're welcome!
https://www.google.com/search?q=over,+underdamped+speaker&rlz=1C1AVNG_enUS675US675&oq=over,+underdamped+speaker&aqs=chrome..69i57j33i160l2.11714j0j4&sourceid=chrome&ie=UTF-8
As Allen noted, the driver is a baffle and it has a pipe end correction = 0.61r, so for an 8" frame = 4*0.61 = 2.44" + 8" = 10.44" effective dia..
This WL and larger fold back and reflect off the cylinder further increasing it's effective baffle response to some extent and as it goes lower the vertical pipe adds a stepped response to lower still, i.e., Allen's 'follow the waves'. 😉
Yes if by 'crisper' you mean more 'forward'/'pronounced' in the driver's pistonic BW.
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1/ MDF is a crappy speaker building material, and yes it does have an orientation.
The surface is at least slighly different than inside giving a “constrained layer”. With translam you are exposing the insides to th eoutside.
Driver size only loosly relates to box size (as bigger drivers tend to need bigger boxes). But a 6.5” driver may need more volume than a 12”.
Note that it only asks for Fs, Vas, Qts, and there is no reference to driver size.
dave
@planet10 ,
Ok....
So two things.
MDF has no orientation. So your fresh cut side would be the same as if you took off the sealed surface.
W.R.T plywood, yes you're exposing the sides which if you paint the inside of the cabinet w an acoustic absorbing paint. (I've seen it done in some videos...) This seals the edge. YMV depending on the quality of the plywood.
In either case... you are able to get some interesting shapes, but in terms of resonance, I would wager that a panel vs translam of the same thickness, the translam would have less resonance.
I agree that translam wastes more material and its a trade off when it comes to cabinet shape.
W.R.T. MDF vs Plywood.. I've seen a lot of speaker makers go that route. (Cost maybe?)
Now this brings me to another problem. My wife.
She doesn't care about sound. She cares about aesthetics.
She hates big boxy speakers.
(Or the color of the speaker cabinet. but that's another story... )
She'd rather use the Pandora App on our TV and listen to the music thru a soundbar (which she hates btw) than a stereo.
So if I'm going to build something... it has to look nice. I mean she'd prefer the look of an ikea bowl speaker over something that was a box and sounded better.
I mean... looking at the CSS DIY kits... I could see building one of those and then painting it (letting the wife pick the color). [I get veto power].
Ok....
So two things.
MDF has no orientation. So your fresh cut side would be the same as if you took off the sealed surface.
W.R.T plywood, yes you're exposing the sides which if you paint the inside of the cabinet w an acoustic absorbing paint. (I've seen it done in some videos...) This seals the edge. YMV depending on the quality of the plywood.
In either case... you are able to get some interesting shapes, but in terms of resonance, I would wager that a panel vs translam of the same thickness, the translam would have less resonance.
I agree that translam wastes more material and its a trade off when it comes to cabinet shape.
W.R.T. MDF vs Plywood.. I've seen a lot of speaker makers go that route. (Cost maybe?)
Now this brings me to another problem. My wife.
She doesn't care about sound. She cares about aesthetics.
She hates big boxy speakers.
(Or the color of the speaker cabinet. but that's another story... )
She'd rather use the Pandora App on our TV and listen to the music thru a soundbar (which she hates btw) than a stereo.
So if I'm going to build something... it has to look nice. I mean she'd prefer the look of an ikea bowl speaker over something that was a box and sounded better.
I mean... looking at the CSS DIY kits... I could see building one of those and then painting it (letting the wife pick the color). [I get veto power].
I con’t think that the case. Let’s let the experts weigh in.
You would lose.
Far too many speakers are made of MDF. Its only asset is cheap.
There are many examples of these. I have designed a few for people.
Given the WAF perhaps a small loudspeaker with subwoofers?
dave
@planet10
<rant>
My wife took my old Vienna Accoustic Hayden bookshelf speakers and painted them (poorly) black because she didn't like their color in my office on my bookshelf. 😡
I bought them when a stereo store was going out of business and they were floor models... great price. She didn't like my towers.
She fought me over having a sound bar and sub woofer for our TV because she didn't like how it looked.
(She hates the sound too.) 🙄
Now I am looking at potentially replacing the Haydens and am considering a DIY option.
(I can fix the Hayden s by repainting them myself. )
</rant>
Note, the Haydens still sound ok. Nothing a powered sub couldn't fix.
If I bought a new set of speakers... KEF R3 Meta.
If I bought a kit. one of CSS's w the high end crossover. ( Its only a 1 day ground ship to me.)
Note: The KEFs are $2200 and the CSS Criton 1TD-X fully built is $2350 while the kit is $1334 and the 2TD-X is $1694 either will need to be painted/finished.
But I've got the itch to build something different.
While looking at speakers... I saw the shape and design of a couple and thought about how to reverse engineer what I saw into something that could be built. Thought about the full drivers which avoid crossovers ... The Fyne F1 series looked interesting. Thought about the F1-8 because it would still be a 'bookshelf' albeit 20" tall, and the F1-5 but that would probably need a powered sub.
There were some other designs too, but the F1-8 stood out.
That's why I started asking about the cabinet internals.
There's more like w the loaded horn designs... like if you consider that to be part of the volume or is it separate?
<rant>
My wife took my old Vienna Accoustic Hayden bookshelf speakers and painted them (poorly) black because she didn't like their color in my office on my bookshelf. 😡
I bought them when a stereo store was going out of business and they were floor models... great price. She didn't like my towers.
She fought me over having a sound bar and sub woofer for our TV because she didn't like how it looked.
(She hates the sound too.) 🙄
Now I am looking at potentially replacing the Haydens and am considering a DIY option.
(I can fix the Hayden s by repainting them myself. )
</rant>
Note, the Haydens still sound ok. Nothing a powered sub couldn't fix.
If I bought a new set of speakers... KEF R3 Meta.
If I bought a kit. one of CSS's w the high end crossover. ( Its only a 1 day ground ship to me.)
Note: The KEFs are $2200 and the CSS Criton 1TD-X fully built is $2350 while the kit is $1334 and the 2TD-X is $1694 either will need to be painted/finished.
But I've got the itch to build something different.
While looking at speakers... I saw the shape and design of a couple and thought about how to reverse engineer what I saw into something that could be built. Thought about the full drivers which avoid crossovers ... The Fyne F1 series looked interesting. Thought about the F1-8 because it would still be a 'bookshelf' albeit 20" tall, and the F1-5 but that would probably need a powered sub.
There were some other designs too, but the F1-8 stood out.
That's why I started asking about the cabinet internals.
There's more like w the loaded horn designs... like if you consider that to be part of the volume or is it separate?
All,
I do have to apologize in that I'm all over the place on this...
I'm still trying to get ideas and to better understand some of the issues w speaker cabinet designs.
Like I said, this is a thought exercise at the moment. It may come to nothing. Or if I still have the free time... maybe I can build it.
-Mike
I do have to apologize in that I'm all over the place on this...
I'm still trying to get ideas and to better understand some of the issues w speaker cabinet designs.
Like I said, this is a thought exercise at the moment. It may come to nothing. Or if I still have the free time... maybe I can build it.
-Mike
Way more degrees of freedom than simpler boxes so the designer needs different tools and lots more experience.
dave
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Dave,
On thing I was thinking about testing...
Imagine you created a translam cabinet w a thicker wall.
Just to keep it simple, think of cutting a D shape, where you are placing the drivers on the flat side of the D.
You're using 3/4" MDF (or similar)
In two of the rings, you cut a channel in the center. Lets say 1/8" deep.
Now if you print a spline that is 1/4" in height and then in the middle you have a flat part that had some width (1/16") so you end up w a gasket, and place it in between the two rings.
Would that reduce the resonance? In theory you're decoupling the two sections w a different material and you should retain a good air seal, even if not glued.
-Mike
On thing I was thinking about testing...
Imagine you created a translam cabinet w a thicker wall.
Just to keep it simple, think of cutting a D shape, where you are placing the drivers on the flat side of the D.
You're using 3/4" MDF (or similar)
In two of the rings, you cut a channel in the center. Lets say 1/8" deep.
Now if you print a spline that is 1/4" in height and then in the middle you have a flat part that had some width (1/16") so you end up w a gasket, and place it in between the two rings.
Would that reduce the resonance? In theory you're decoupling the two sections w a different material and you should retain a good air seal, even if not glued.
-Mike
Yes, saw some of the calculations.
Again... that's kinda why I started this thread...
Can you build something that has a cool look over the standard box, and still punch above its weight?
(You know those videos of people building open baffles for ~$1200 in parts but claim it sounds like a $10K or better speaker)
To me, that's the challenge.
(Ok, its an excuse as a distraction from my day job...)
MDF is like thick paper made from a goop of wood fibre and water-soluble glue. A lot of glue. It gets its stiffness from dry material bulk and fibre length is not long enough to be structural. Think of it as woody plastic which will start vibrating at certain frequencys and power. I have a high excursion 7" in a ported MDF box smaller than a cubic foot. At a good volume the cab buzzes like cardboard but same thing happens with plywood at little further up the volume. Try to brace with something that itself wont vibrate at certain frequencies or power otherwise an MDF brace can even play the box like a guitar string 😀
Its fine if you not using enough power to get it to vibrate
Its fine if you not using enough power to get it to vibrate