Noob Speaker design question... Starting from scratch.

[im_gumby]

Hi,

Had some spare time over the holidays and I kinda started looking at my speakers.
Was surfing da web and landed on a hi fi site and this speaker caught my eye.

Fyne Audio F1-8 Bookshelf Loudspeaker. Ok, its 10.5K (USD) and a bit out of my price range.
But I thought about building something similar. Like a poor man's version.

I wanted to build it around Radian's 2CRF6430 12”coaxial with planar ribbon HF driver.
(The data sheet even has a crossover recommended.)

So assuming that the driver and cross over are selected... I was curious about the speaker cabinet.
The Fyne has a downward facing port that hits a cone, and I was thinking that it would be possible to print the entire cabinet using a 3D printer.
There's a lot of videos on the topic of 3D printing and I think its something I can experiment with.
Its also an excuse to get a 3D printer... or I could just bug my nephew and buy him the PLA.

My question(s)...
1) Is this insane? The drivers are ~$450 each and the crossover is ~$105 each.
2) In terms of frequency range... good enough for a bookshelf. 40Hz-30KHz.
3) Passive vs DSP. Since its a coaxial, w a recommended known crossover... why would you consider a DSP?
4) What test equipment should I buy?
5) I like the design, but would it make sense to start w a standard box?


Note: This is something I thought about doing... I figure its going to be at least a grand on the drivers/crossover / wiring, then the cost of the cabinet.
(Printing because I gave away my woodworking tools and I'd need to get a new router.)
Also, if I had to buy speakers, I'd consider the KEFs Meta R3 which is roughly 2 the price. The idea of building is part hobbyist if I have the time.
The KEF LS50Meta are roughly the same price as this build... could do a cabinet like theirs as an option. (Although the Fynes look cool)

Thx.

 

[Rick Sykora]

Unless you plan to build more speakers, imo, does not make sense to invest in time and measurement equipment for a one off.

Have heard some folks acquiring KEF drivers, so if you can find a completed design you like, might be worthwhile to build.

 

[im_gumby]

Unless you plan to build more speakers, imo, does not make sense to invest in time and measurement equipment for a one off.

Have heard some folks acquiring KEF drivers, so if you can find a completed design you like, might be worthwhile to build.

Thanks for the quick response.
I was first trying to mimic the Fyne, which appears to be a step or two above the KEF R3 Meta.
Honestly, it would be cheaper to just buy the R3 Meta, but was thinking about this as a hobby.

I saw some of the KEF Meta drivers on e-bay... sold one at a time.
I'm a bit skeptical of those drivers. Tend to prefer buying parts from retailers.

I agree that buying testing equipment may be a waste... depending on the cost...
But I am curious about the cabinet design. That's why I was curious about testing equipment.

I mean I can print the cabinet, but everything I'm seeing is that there needs to be additional dampening of the cabinet itself.
Was going to try some experiments in terms of wall design.

 

[DVDdoug]

My main recommendation is always use speaker design software to optimize & model the cabinet (with the particular driver's Thiele-Small parameters). I've used WinISD (free).

I mean I can print the cabinet, but everything I'm seeing is that there needs to be additional dampening of the cabinet itself.

It needs to be stiff, which can mean dense and/or braced, etc., and you generally need some lining or stuffing to reduce internal reflections/resonances. Otherwise, the main characteristics are volume, and port dimensions if it's ported. With some drivers, a sealed cabinet works better and the software will help with that. And there is usually a trade-off between the cutoff frequency, which can be lower with a tuned port, and the roll-off slope which isn't as steep in a sealed cabinet.

 

[Rick Sykora]

If you have the time and the space (for measurement rig), you will spend at least another $300-400 on an audio interface, microphone, mic stand and cables. A solid design from scratch is a lot of time calibrating test equipment, measuring, designing and iterating a few times. Suggest you look at the Directiva r1.2 thread as a reference. Depending on your technical chops and tenacity, you are looking at least that amount of effort. That design also has the advantage of using r1 as a springboard.

I think many tend to underestimate what goes into a speaker design. Even one seemingly as reasonable as the LS50 meta is not insignificant. Your target is beyond that and so if you intend to achieve that level of performance, should plan to devote serious time to it. If that is what you want to do, please carry on. Otherwise, would look for a Troels or other established designer and build one of theirs. Tbh, a Fyne knockoff using different parts is a major effort for even an experienced designer.

 

[617]

Given what you seem to know about loudspeaker design, I would not recommend you initiate a design. You will be able to make something that sounds cool, but if you want something that will sound excellent which you will be able to enjoy for the rest of your life, I would not go down that path. I have designed and built more speakers of various types than I can easily remember, and I don't think I've ever built something that performs as well as $500 active monitors that are available these days. Designing speakers requires a lot of knowledge, not just of drivers and crossovers and acoustics, but measurement as well. Measuring and simulating the summation of drivers in space is incredibly tricky and requires a lot of time and a lot of space.

If you want to build a state of the art speaker, you have a lot of good options in the form of kits and proven designs.

For a small speaker, look at the 'Directiva' project here. For a slightly larger project, look for the Philharmonic BMR speaker, which comes as a kit or finished unit. For a large speaker, consider combining one of the previous designs with subwoofers (a far more approachable project for a first-timer). In addition to these designs, there are dozens of designs using high end drivers you can try; perhaps the Kairos speaker or the Spirit Wind monitor, both designed by the late Jeff Bagby.

If you want a taste of the best of esoteric audio, consider the Linkwitz LX521 design, which can be purchased as a kit. Be warned, it requires lots of outboard electronics and amplifiers, but it does things other speakers cannot do.

I relate to your confidence - I felt the exact same way you do once. Surely I can build speakers as good as some $10K design! And I can! And so can you. But you're going to spend an enormous amount of time and money doing it, and unless you want to make this a profession, you'll be happier letting someone else do the design.

 

[kemmler3D]

Tbh, a Fyne knockoff using different parts is a major effort for even an experienced designer.

Bears repeating. If knockoffs were so easy, all knockoffs would be good. In practice it's a minority of knockoffs that get close to the original. And we're talking knockoffs by professionals with access to factories and labs and stuff. The entire (wildly varied) history of LS3/5a units speaks to this.

 

[kemmler3D]

Surely I can build speakers as good as some $10K design! And I can! And so can you.

If you are willing to spend $7K on the parts, it makes it easier.

 

[617]

If you are willing to spend $7K on the parts, it makes it easier.

For me it isn't the money I regret but the time I could have been doing something else. I know so much about making speakers and I'll never make a dime or get girls with that knowledge.

The money is a bitch too though. Paying a guy to deliver Baltic birch. Paying a guy to cnc it. Buying lacquer. Buying felt. Buying a crimping tool. Endless rabbit hole.

 

[AudioSQ]

You say the data sheet has a crossover recommended.. is this already a design you'll just be copying? Or is it just a recommended crossover for one of the drivers?

I don't know a ton about 3D printing boxes but if you're using a 12" driver that is a pretty big box. I would think to make it inert would take an obscene amount of spools of PLA. You see a lot of cheap plastic computer speakers, you don't see too many high end speakers in plastic boxes.

If you want to get into the hobby of speaker designing, go for it, but I'd probably start off much smaller and with a kit. Like anything you have to learn and improve your skills. It won't be cheaper, but it will be fun.. maybe.

If you just want more bang for your buck then do a proven design. There are even several kits with boxes so you don't have to get all the tools.

Then again sometimes it's just fun to go for it and enjoy the ride.

 

[voodooless]

I don't know a ton about 3D printing boxes but if you're using a 12" driver that is a pretty big box. I would think to make it inert would take an obscene amount of spools of PLA

Well, you can just make the walls hollow and fill it with sand. That saves a lot of material and will make an inert enclosure.

A lot has already been said. As for the recommended filter:

It will not yield a very smooth frequency response. This is where an active design would most certainly excel. Also, the off-axis drop-off above 10 kHz is quite severe. Probably due to the planar ribbon driver. A normal compression driver may do a better job.

For Hifi, you’ll probably also want lower tuning otherwise you won’t make the 40Hz. That will also lead to you needed (more) baffle step compensation. You’ll loose quite a bit of efficiency.

 

[Rednaxela]

Out of interest, is this your first speaker build? If so, in your position I think I would get a pair of cheap second hand KEF Q100s, Q150s or Q350s. Find or work out the T/S parameters of their Uni-Q drivers and see how far you can get with those.

This approach has many advantages:

1) The initial outlay is relatively low
2) There is a lot of measurement data available about the speakers in their original form, so you will have a very well documented reference you can compare your efforts against, starting with just your measurement efforts
3) In all three speakers the drivers do not seem to be the limiting factor, so it does actually pay to optimize cabinet, port and crossover design
4) There are excellent and well documented examples of people who did exactly this
5) You have a working crossover that you won’t have to worry about initially, for instance when your first step would be to move the port to the bottom
6) The cabinets will probably be a lot smaller than what’s required for 12” drivers so easier to 3D print prototypes
7) Once you can prove with measurements that you have truly outdone KEF, you will most certainly be able to answer your five questions yourself. On the other hand, as long as you can’t, it’s quite unlikely you’ll be ready to make your poor man’s Fynes the success you’re now hoping them to be. In short it would be a great little project to find out if you have it in you in the first place, if this makes sense. (FWIW I know I don’t.)

Hope this helps and good luck!

 

[im_gumby]

If you have the time and the space (for measurement rig), you will spend at least another $300-400 on an audio interface, microphone, mic stand and cables. A solid design from scratch is a lot of time calibrating test equipment, measuring, designing and iterating a few times. Suggest you look at the Directiva r1.2 thread as a reference. Depending on your technical chops and tenacity, you are looking at least that amount of effort. That design also has the advantage of using r1 as a springboard.

I think many tend to underestimate what goes into a speaker design. Even one seemingly as reasonable as the LS50 meta. Your target is beyond that and so if you intend to achieve that level of performance, should plan to devote serious time to it. If that is what you want to do, please carry on. Otherwise, would look for a Troels or other established designer and build one of theirs. Tbh, a Fyne knockoff using different parts is a major effort for even an experienced designer.

I don't know that calling it a knockoff is correct. More inspired by their design...
I know I won't get the same level of components or the sound. It was more the aesthetics and the goal of producing good sounding speakers for the price.
Also being realistic it would be cheaper to buy the actual speaker than trying to duplicate it. I mean the KEFs sound great.

In my home office, I have a small Arcam Solo Uno driving my old Vienna Accoustic Haydens (Bookshelf) that I got on fire sale many moons ago. (Store was going out of business.) It still does the job, but got the itch to build something new.

And to your point, before I do anything its a thought exercise on cabinet design. (Shape, volume, etc... )

 

[im_gumby]

Out of interest, is this your first speaker build? If so, in your position I think I would get a pair of cheap second hand KEF Q100s, Q150s or Q350s. Find or work out the T/S parameters of their Uni-Q drivers and see how far you can get with those.

This approach has many advantages:

1) The initial outlay is relatively low
2) There is a lot of measurement data available about the speakers in their original form, so you will have a very well documented reference you can compare your efforts against, starting with just your measurement efforts
3) In all three speakers the drivers do not seem to be the limiting factor, so it does actually pay to optimize cabinet, port and crossover design
4) There are excellent and well documented examples of people who did exactly this
5) You have a working crossover that you won’t have to worry about initially, for instance when your first step would be to move the port to the bottom
6) The cabinets will probably be a lot smaller than what’s required for 12” drivers so easier to 3D print prototypes
7) Once you can prove with measurements that you have truly outdone KEF, you will most certainly be able to answer your five questions yourself. On the other hand, as long as you can’t, it’s quite unlikely you’ll be ready to make your poor man’s Fynes the success you’re now hoping them to be. In short it would be a great little project to find out if you have it in you in the first place, if this makes sense. (FWIW I know I don’t.)

Hope this helps and good luck!

I guess in terms of 'cutting corners' I wanted to do a coaxial speaker because it had a recommended matching cross over. You are right I don't have to go with the 12" but the smaller speakers didn't have the lower range. My current Hayden s are spec'd to do 40-20K. (Although that's for the newer model, mine is ~20 yrs old)

To your point...
Yes, these are my first build. I guess I could start small, do a coaxial pair of desktops to test out the cabinet build.
All of my wood working stuff is split between my nephews and my router got lost in a move several years ago. Hence 3D printing.
I've seen Hexibase ?sp? videos and he adjusted the fill on an all pla print. I was thinking of using modeling clay in the cabinet walls to help deaden the sound but haven't seen anyone try that. Then internally use something else. (Also internal bracing.)

The thing I liked about the Fyne is that your driver is off center (higher) and the curves.

 

[Rick Sykora]

I don't know that calling it a knockoff is correct. More inspired by their design...
I know I won't get the same level of components or the sound. It was more the aesthetics and the goal of producing good sounding speakers for the price.
Also being realistic it would be cheaper to buy the actual speaker than trying to duplicate it. I mean the KEFs sound great.

In my home office, I have a small Arcam Solo Uno driving my old Vienna Accoustic Haydens (Bookshelf) that I got on fire sale many moons ago. (Store was going out of business.) It still does the job, but got the itch to build something new.

And to your point, before I do anything its a thought exercise on cabinet design. (Shape, volume, etc... )

Ok, call it a derivative if you prefer, most of what I posted still applies...

Certainly, part of the speaker cost is the fabrication and you can absorb that yourself. However, as a speaker is a system design, KEF (and others) apply CAD, do vibration analysis and apply materials beyond what most of us hobbyists can. This keeps them from doing expensive redesigning. From experience, I have more than a few drivers around that did not fit my design plans in the end. If you are putting in the effort, plan to buy spares too. You may blow one during design or in later use. The hobbyist is also their own service and support. I get I may sound discouraging but hope you (and others) choose to pursue the effort knowing the full set of challenges.

 

[fpitas]

pursue the effort knowing the full challenges.

That's the main thing: it's a great hobby, but very daunting especially if you're not already an engineer. Then it's just frustrating

 

[Middle Earth]

Speakers, especially on the high end must have more than generous profit margins
CSS and Madisound have nice kits that maximize your $$$
If you are wanting to build something
These are typically proven designs and have cabinet designs and dimensions
The cross-overs are assembled or ready to assemble
It is a fun thing to do

 

[fpitas]

Some good reading here:

My experience with DIY and it's many frustrations that are not talked about.

Howdy, I don't feel this website is the most active in terms of DIY speakers, but I feel my opinions may be of more value here than other sites. This will probably be quite scatter brained and I'm going to be as open as I can be maybe touching on some deeper personal issues in the end. I got...

www.audiosciencereview.com

 

[hex168]

Some good reading here:

My experience with DIY and it's many frustrations that are not talked about.

Howdy, I don't feel this website is the most active in terms of DIY speakers, but I feel my opinions may be of more value here than other sites. This will probably be quite scatter brained and I'm going to be as open as I can be maybe touching on some deeper personal issues in the end. I got...

www.audiosciencereview.com

Also here:

But you want to design your own loudspeaker

My take on DIY, of which I've done a lot, although mostly in the 80's and 90's when it was easier to do as well as the best designers out there: It is worthwhile as a challenge and learning experience. It is a good solution when you want something that is not adequately addressed by the market, such as a speaker designed for a specific placement, a particular size to fit a difficult spot, or an unusual but valid design principle such as CBT, floor-to-ceiling line array, or dipole. Or floor-to-ceiling dipole line array. Also for very large speakers where much of the expense in retail is in moving the thing. Normal speakers are more cost-effectively bought than built, particularly given the "known good" aspects of speakers tested here or by Erin.

 

[DVDdoug]

you will spend at least another $300-400 on an audio interface, microphone, mic stand and cables.

You can get a calibrated USB measurement mic for about $100 USD and REW (software) is FREE.

And... measurement isn't going to help that much unless you are going to experiment with different drivers or modifying the crossover, etc. It could help with tweaking the port but you'd need to make the measurements outdoors to eliminate room effects, and the design software should give you a pretty good idea of the bass response.

I would also generally recommend building your first speaker with more affordable components, but it's your money and you know what you can comfortably afford... And I kind-of like the idea of a coax speaker because the woofer & tweeter are matched and made to work together.