I tend to disagree. Yes, there will probably be only one (or a very small number) of builders for the prototypes. Yet, the whole project will loose a lot of its appeal if it's just a guy building his speakers, helped by some comments from a bunch of diyAudio members. I strongly believe a poll of what you want to achieve would help tremendously to get a sense of what people want / need, and what makes the project attractive. With a bit of luck, this will align with what the prototype builder(s) want to do during their hobby time.
I think you're jumping the gun here. There is a gazillion of woofers out there, and they all work. Narrowing this down would require some constraints regarding box size/volume, efficiency, low-frequency extension, looks, etc. Again, a proper list of well-founded design targets would help a lot.
I seem to be playing a somewhat more prominent role than I intended and people seem to be wanting to pin down a specific design much faster than I expected. Nonetheless the theme/vision thing does need to be clear if people are to know if they are in, out or casually monitoring.
To me a monkey coffin conjures up an image of a large 3/4 way domestic speaker from the 70s with dimensions something like 750 x 450 x 350mm (height, width, depth), plain wooden finish with a plain grille and sitting on a short stand. The sort of speaker I wanted when young but couldn't afford.
Modern commercial examples of monkey coffins would seem to be:
The intention for my build (if it happens) would be to combine retro cosmetics with modern studio monitor technical performance. The cosmetics can be varied to taste with a DIY project and therefore isn't a significant part of the spec. Others prefer to have drivers on a flat baffle in the manner of the Dovedale and so the proposal is to design a removable half baffle to support different midrange/tweeter combinations and orientation. Of course there is no need to build a speaker with a removable half baffle if it is not wanted but including one potentially widens the appeal of the group project and, if we can get the design right, should improve the vibrational behaviour of the cabinet.
I personally want to start messing about with the design and manufacture of mid and tweeter waveguides in order to get a technical performance w.r.t. radiation pattern approaching those of the best studio monitors. Likely a touch down on clean SPL due to the use of standard range drivers but this should be OK in the home. Others in the forum know a lot more than me about the DIY manufacturing side of such things using addititive and/or subtractive NC machines available to DIYers and so I hope they take an interest and contribute even if they have no wish to build a full speaker.
I have little experience and little interest in passive crossovers and would rely on others to contribute here given many prefer passive crossovers. On the active side people go about things in a number of different ways and with very different costs. I would like to learn a bit more about the pros and cons of the alternatives.
My manufacturing skills are modest and so if the builds turn out well I can hopefully follow what some others are doing.
Where I hope to make a contribution to the project initially is on the detailed design side via 3D simulation of the acoustics and vibration. As I have mentioned elsewhere I am in the early stages of developing some software in this field and also run one or two open source 3d packages. A project like this could be useful in determining what relevant questions can or cannot be answered in a satisfactory quantitative manner.
At this early stage I would suggest we gather information about configurations people have a significant interest in before examining some of their pros and cons via simulation and possibly drivers availability. At this point in the discussion I think we may have settled on but please chime in if I am assuming too much:
Note an optional removable rotatable baffle will constrain the height-to-width ratio to be roughly 2:1. The Gema above for example would need to be a bit taller and less deep particularly with a port located below the woofer.
The above seems a reasonable set of options to me to explore before pooling results and seeing which configurations people are keen to take further. There is no need for a single configuration indeed the project would likely be more interesting with several. There is a need though within a group project for much of the speaker to be common such as the same woofer module with different tweeter/midrange modules.
If we post a poll now what might be useful information to gather? Perhaps strength of interest in:
To me a monkey coffin conjures up an image of a large 3/4 way domestic speaker from the 70s with dimensions something like 750 x 450 x 350mm (height, width, depth), plain wooden finish with a plain grille and sitting on a short stand. The sort of speaker I wanted when young but couldn't afford.
Modern commercial examples of monkey coffins would seem to be:
- classic retro speakers like those from Harbeth, Spendor, Graham Audio,...
- modern retro like the Wharfedale Dovedale which is a modern speaker with retro cosmetics
- midfield studio monitors like those from Neumann, Genelec, JBL,...
The intention for my build (if it happens) would be to combine retro cosmetics with modern studio monitor technical performance. The cosmetics can be varied to taste with a DIY project and therefore isn't a significant part of the spec. Others prefer to have drivers on a flat baffle in the manner of the Dovedale and so the proposal is to design a removable half baffle to support different midrange/tweeter combinations and orientation. Of course there is no need to build a speaker with a removable half baffle if it is not wanted but including one potentially widens the appeal of the group project and, if we can get the design right, should improve the vibrational behaviour of the cabinet.
I personally want to start messing about with the design and manufacture of mid and tweeter waveguides in order to get a technical performance w.r.t. radiation pattern approaching those of the best studio monitors. Likely a touch down on clean SPL due to the use of standard range drivers but this should be OK in the home. Others in the forum know a lot more than me about the DIY manufacturing side of such things using addititive and/or subtractive NC machines available to DIYers and so I hope they take an interest and contribute even if they have no wish to build a full speaker.
I have little experience and little interest in passive crossovers and would rely on others to contribute here given many prefer passive crossovers. On the active side people go about things in a number of different ways and with very different costs. I would like to learn a bit more about the pros and cons of the alternatives.
My manufacturing skills are modest and so if the builds turn out well I can hopefully follow what some others are doing.
Where I hope to make a contribution to the project initially is on the detailed design side via 3D simulation of the acoustics and vibration. As I have mentioned elsewhere I am in the early stages of developing some software in this field and also run one or two open source 3d packages. A project like this could be useful in determining what relevant questions can or cannot be answered in a satisfactory quantitative manner.
At this early stage I would suggest we gather information about configurations people have a significant interest in before examining some of their pros and cons via simulation and possibly drivers availability. At this point in the discussion I think we may have settled on but please chime in if I am assuming too much:
- a large monitor with a height around twice the width and a depth likely a bit less than the width
- 3 way with 10" or 12" woofer
- removable tweeter/midrange baffle (optional)
- no waveguides, waveguide on tweeter, waveguide on tweeter and midrange
- ported or sealed
- active or passive crossover
- standard range drivers implying a driver budget in the range £500-1000
Note an optional removable rotatable baffle will constrain the height-to-width ratio to be roughly 2:1. The Gema above for example would need to be a bit taller and less deep particularly with a port located below the woofer.
The above seems a reasonable set of options to me to explore before pooling results and seeing which configurations people are keen to take further. There is no need for a single configuration indeed the project would likely be more interesting with several. There is a need though within a group project for much of the speaker to be common such as the same woofer module with different tweeter/midrange modules.
If we post a poll now what might be useful information to gather? Perhaps strength of interest in:
- a removable tweeter/midrange half baffle
- sealed cabinet
- budget drivers
- 10" driver
- passive crossover
The Revival Atalante 5 might be worth a look for inspiration from a whole speaker manufacturer. Not sure what the drivers are but the blurb talks about RASC technology.
https://revivalaudio.fr/atalante-5/
https://revivalaudio.fr/atalante-5/
On the passive crossover i and many can help, if you supply us with good measurments of the drivers in the box. But a passive crossover is mandatory for me to call it a monkey coffin. it's part of the design concept of that type of speaker. All the original models had it, and a big part of the monkey coffin speaker is that it runs from any standard amplifier that is powerfull enough, and especially from classic integrated amps like popular in that time.
Which does not mean that your personal copy couldn't be active, but for a finished monkey coffin design there should be a passive crossover option also, that is mandatory. If you can't do that, delegate it someone (or many) tha can do that.
Which does not mean that your personal copy couldn't be active, but for a finished monkey coffin design there should be a passive crossover option also, that is mandatory. If you can't do that, delegate it someone (or many) tha can do that.
If you are trying to keep total driver costs to €250-€300 per side and we go with a 12" woofer, want low distortion and have an F3 of 40Hz I'm not sure there are more woofers than you can count on two hands.
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Other things that come from the original design is that it's very flexibel in placing it for a half decent sound, so port in the front, and with a slow slope on the woofer lowcut that fits standing against a wall. A sealed could be perfect for that indeed, but also some kind of damped ported cabinets can do that.
+ Keeping cost modest.
^^I think there are a LOT of people who don't design their own speakers but like DIY that would like a speaker like this.
Are you considering optional drivers? For example, lets say that a 5.25" mid is selected. It might not be hard to make a crossover for more than one 5.25" mid, and even for different tweeters. I'm not suggesting a multitude of designs, but maybe two or three. There would be extra work making measurements, but x-over Sims should not be very difficult. It's hard to satisfy everybody, but a lower cost option might be attractive to some builders. I have no desire to build this for myself, so I have no bias in the budget, or size.
I guess it's obvious, but future driver availability could be a factor. I used to buy Peerless, but now the brand is hard to get. For example, Peerless has a very cheap 5.25" woofer, that I'm told makes a decent mid. I think it's under $25, and doesn't need elaborate filtering.
I guess it's obvious, but future driver availability could be a factor. I used to buy Peerless, but now the brand is hard to get. For example, Peerless has a very cheap 5.25" woofer, that I'm told makes a decent mid. I think it's under $25, and doesn't need elaborate filtering.
Perhaps this begins with a frequency and an angle. Ie, fitting the angle above that frequency, and falling back to half space below until the baffle opens to full space.
While these two waveguide constraints could be chosen for auditory reasons, it's possible they would fall back to practical reasons. For example, there's a lower limit when using domes, not to mention the size the waveguide should be. It would also dictate the size of the mid needed.
The two steps to half then full space could also be chosen and designed for.
You could default to offering transfer functions. Anyone could configure their own DSP for that.. or use the standard speaker level crossover on offer.
This is the Peerless driver.
https://www.parts-express.com/pedocs/specs/264-1078--tymphany-sds-p830656-spec-sheet.pdf
I kind of like this tweeter for the money. https://www.parts-express.com/pedocs/specs/264-1386--tymphany-h26tg45-06-spec-sheet.pdf
https://www.parts-express.com/pedocs/specs/264-1078--tymphany-sds-p830656-spec-sheet.pdf
I kind of like this tweeter for the money. https://www.parts-express.com/pedocs/specs/264-1386--tymphany-h26tg45-06-spec-sheet.pdf
The questions of "sealed vs. ported" and "size of woofer" are quite technical. I wouldn't use this as part of the design targets, but rather focus on how / where people would (not) want to use the speakers. Targets that relate more directly to WAF and existing equipment may be more meaningful as design targets. These will then dictate part of the implementation (choice of woofer, sealed vs. ported, etc.).
I have a pretty strong opinion on the passive vs. active x-over for such a project, but I am happy to respond to this question in the poll.
On a more general thought for the project, I guess it will be important that the person(s) building the prototypes will also be able to make good measurements to validate the design / models.
I won't say that this project is impossible, but likely improbable.
I've followed some of HifiJim's projects and believe the way he's done it is sensible. He defines his objectives, takes input from members, analyses their ideas and then makes a decision as to whether it enhances, or detracts from, his initial objective and moves on. The critical aspect is that it is one person's concept, their idea, their vision.
If the OP has defined his objectives, he should proceed. Whether people agree, or disagree, is their choice.
What further complicates this is the regional affordability, or in some cases, the availability, of drivers. This is particularly relevant for an 'economical' system.
Just my thoughts ...
I've followed some of HifiJim's projects and believe the way he's done it is sensible. He defines his objectives, takes input from members, analyses their ideas and then makes a decision as to whether it enhances, or detracts from, his initial objective and moves on. The critical aspect is that it is one person's concept, their idea, their vision.
If the OP has defined his objectives, he should proceed. Whether people agree, or disagree, is their choice.
What further complicates this is the regional affordability, or in some cases, the availability, of drivers. This is particularly relevant for an 'economical' system.
Just my thoughts ...
^Regarding regional affordability....definitely something to keep in mind.
I think most people are aware the Dayton Audio products are priced pretty much below other brands in the US. Dayton and SB Acoustics are two of the best values, but Dayton is pretty significantly less than SBA here in the US.
I was checking SoundImports earlier this week to see how much the 10" Dayton Audio Reference woofer was in Europe and was shocked to see how close it was to the Scan-speak discovery woofer.
SoundImports (Netherlands)
Dayton Audio RS270-8 € 170
Scan-speak 26W/8534G00 € 180
In the US
Dayton € 128 (From Parts Express, and pretty easy to get 10% or more off of this price)
Scan-speak € 200 (from Madisound)
I think most people are aware the Dayton Audio products are priced pretty much below other brands in the US. Dayton and SB Acoustics are two of the best values, but Dayton is pretty significantly less than SBA here in the US.
I was checking SoundImports earlier this week to see how much the 10" Dayton Audio Reference woofer was in Europe and was shocked to see how close it was to the Scan-speak discovery woofer.
SoundImports (Netherlands)
Dayton Audio RS270-8 € 170
Scan-speak 26W/8534G00 € 180
In the US
Dayton € 128 (From Parts Express, and pretty easy to get 10% or more off of this price)
Scan-speak € 200 (from Madisound)
I am one of the ones you are talking about no doubt... I do tend to make decisions quickly, and I am also always open to revision. I recognize that in a collaborative project, we all think/work/decide at a different pace. As for your "somewhat more prominent role", well it is your vision. It is a good one, very realistic and doable, and also one which probably has a broad interest as @A4eaudio mentioned.
This sounds very good to me. Not to constraining, but enough constraint/guidance to get us started. If no one posts any alternate ideas, we may assume that we have a consensus... but at some point I recommend that you make a definitive statement about the initial design constraints.
I look forward to seeing what you come up with. I always thought that with your background and experience, you could make a valuable contribution to the DIY tool set.
j.
How do you voice a monkey coffin, that sits close to the wall? If I have an 87dB mid, and can cover 400hz and up with it, and the tweeter, then what would be the maximum woofer sensitivity without the bass being overwhelming? If a 12" woofer shows 92dB at 100hz, is that going to be too much for an 87dB mid? The 12" woofers that I looked at seem to be around 90dB, or higher. I would prefer 87dB, and pad the mid if needed. I've not placed speakers near the wall for years, and generally make mine with full BSC, or close to it.
How costly is an active DSP setup, if you already have amps in an AVR?
How costly is an active DSP setup, if you already have amps in an AVR?
Yes, and I think the situation is reversed with respect to Wavecor, which is more affordable in Europe than in the US.
I know our friends in India are partial to SBA and Satori because they are widely available and priced nicely compared to other brands.
It is very hard to say in advance if a project will flow to completion. Yes it is true that I have had several successful projects, but my way of doing things is not the only way, and probably not the best way for a collaborative project, but it is the best way for me.
I see your point. If the project is going to appeal to a wide group, it needs to be a design which meets the needs of many people. But this is actually quite rare, and most DIY designs end up being one of a kind. Your OSMC and the Elsinore are two of the rare exceptions. In my view, getting the first set designed, developed, built, tested, voiced, and optimized is the biggest hurdle. In order to clear that hurdle, the project needs at least one passionate leader who is willing to do the work and spend the money on the first prototype. The speaker must have a strong appeal to that person in particular, or there will be no motivation to complete the project.
Jim is perfectly rigth. It belongs to Handy to focus little by little on the choices.
What however could be discusted aside, is not the personal choices that stay the target, but instead general considerations to help further more on the choices.
For instance : form factor at iso volume load; sizing of the drivers according the room volume, wave guide or not according the layout of the loudspeakers in the room shape and size ; wwhere to focus the budget on the drivers, more towards the bass unit, more towards the mid... ; should one mix cone material in the design, etc .
Active or passive and it is not the same project anymore.
We know the budget already, the maximum flat (-f3), not yet the F6/F10 which matter more imho; and the load : vented; and more or less the size and form factor (for aesthical, my understanding; so should be added the stand price).
When the most difficut will be chosen, i.e. the bass driver, then the thread will focus a lot of the design and there will be less general considerations and method advices and more computed datas.
My 2 cents
What however could be discusted aside, is not the personal choices that stay the target, but instead general considerations to help further more on the choices.
For instance : form factor at iso volume load; sizing of the drivers according the room volume, wave guide or not according the layout of the loudspeakers in the room shape and size ; wwhere to focus the budget on the drivers, more towards the bass unit, more towards the mid... ; should one mix cone material in the design, etc .
Active or passive and it is not the same project anymore.
We know the budget already, the maximum flat (-f3), not yet the F6/F10 which matter more imho; and the load : vented; and more or less the size and form factor (for aesthical, my understanding; so should be added the stand price).
When the most difficut will be chosen, i.e. the bass driver, then the thread will focus a lot of the design and there will be less general considerations and method advices and more computed datas.
My 2 cents
EUR 30 difference. I'd say that's just zilch once you consider a complete loudspeaker system. You'll want the right part for the job. I'd hate to save 30 EUR and get the wrong part.