I'd be spending at least the same on the midrange as the woofer.
The midrange is probably the most important driver, depending on how easy it is to work with, but more importantly how resolving it is while being able to deliver a wide dynamic range. How low you can cross it is another criteria. A higher price tag should equate to better resolution and an acceptably easy to tame FR using basic passive filtering.
The woofer should have alot of xmax, low distortion and the ability to play low in a reasonable size enclosure. Try to aim for 90+ dB/W. If a ported design is preferred, aim for a Qts of .35 to .42 but make sure you budget for an.enclosure volume similar to the Vas of the woofer.
"I'd be spending at least the same on the midrange as the woofer.
The midrange is probably the most important driver, depending..."
The difference is, there seems to be plenty of good midranges around $75. Not many (any?) high quality 12" woofers.
There may be better choices, but as an example, here are two midranges that offer a lot of sound quality for the price:
Peerless NE149 $76
Aurum Cantus AC-130F1 $71
The midrange is probably the most important driver, depending..."
The difference is, there seems to be plenty of good midranges around $75. Not many (any?) high quality 12" woofers.
There may be better choices, but as an example, here are two midranges that offer a lot of sound quality for the price:
Peerless NE149 $76
Aurum Cantus AC-130F1 $71
I have posted a spec in the OP. Please post suggestions for improvements.
Some comments:
The output requirement is to allow the speakers to be included as 2 of the subs in a distributed sub system or to operate reasonably as a standalone pair of speakers without subs. A ported 12" woofer should be comfortable, a modern ported 10" woofer is also likely suitable but sealed may not be.
If the drivers are adequately sized and adequately designed for low distortion within the operating range then the sound radiation pattern and how it interacts with the room dominates the perception of sound quality. Controlling the sound radiation pattern is therefore intended to be a significant part of the project.
The motivation for most configuration being suitable for passive crossovers is because many DIYers prefer passive crossovers. Not all allows for the flexibility of DSP to be used to achieve more optimum sound radiation patterns.
The motivation for straightforward to build versions with drivers bolted to a flat baffle is because this is what many DIYers prefer. It also acts as something to measure against for the more complex waveguide versions.
The flexible placement follows from the rotatable mid/tweeter assembly, front ports and to some extent a configurable crossover. All are optional. The baffle could be solid, the ports in the rear and the crossover a fixed passive one.
The use of standard range drivers sets a driver budget in the range £500-1000.
Some comments:
The output requirement is to allow the speakers to be included as 2 of the subs in a distributed sub system or to operate reasonably as a standalone pair of speakers without subs. A ported 12" woofer should be comfortable, a modern ported 10" woofer is also likely suitable but sealed may not be.
If the drivers are adequately sized and adequately designed for low distortion within the operating range then the sound radiation pattern and how it interacts with the room dominates the perception of sound quality. Controlling the sound radiation pattern is therefore intended to be a significant part of the project.
The motivation for most configuration being suitable for passive crossovers is because many DIYers prefer passive crossovers. Not all allows for the flexibility of DSP to be used to achieve more optimum sound radiation patterns.
The motivation for straightforward to build versions with drivers bolted to a flat baffle is because this is what many DIYers prefer. It also acts as something to measure against for the more complex waveguide versions.
The flexible placement follows from the rotatable mid/tweeter assembly, front ports and to some extent a configurable crossover. All are optional. The baffle could be solid, the ports in the rear and the crossover a fixed passive one.
The use of standard range drivers sets a driver budget in the range £500-1000.
I am collecting some useful example speakers. Suggestions?
12" woofer
10" woofer
12" woofer
- Harbeth M40 (750 x 432 x 388)
- Spendor Classic 100 (700 x 370 x 433)
- Revival Audio Atlante 5 (710 x 420 x 355)
- K&H O 500C (750 x 400 x 447)
- Genelec 1237A (680 x 400 x 380)
- ATC SCM100ASL Pro (832 x 398 x 581)
- OSMC (682 x 368 x 420)
- SB Acoustics Gema (720 x 430 x 360)
- TG Faital-12-430 (680 x 375 x 400)
10" woofer
- Wharfedale Dovedale (660 x 370 x 447)
- Neumann KH 420 (645 x 330 x 444)
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Thoughts on an initial study to get things going and to provide a basis for making decisions and running possible polls.
Sort out how to organise, collect and share the work on the project.
Collect a list of similar speakers for guidance on technical and aesthetic aspects and to measure performance against.
Given the baffle will be wide what are the pros and cons of a minimum reasonable width or a significantly wider one?
For a wide baffle and optionally waveguides are the technical disadvantages of sharp baffle edges significant?
Is it viable to stiffen the woofer cabinet sufficiently to raise the frequency of the lowest mode/resonance of significance (i.e. driven and radiating towards the listener) above the passband of the woofer? If not, what is an effective way to damp the significant modes/resonances and/or reduce the amount they are driven.
How beneficial is passive isolation of the midrange/tweeter baffle from the woofer structure?
If the midrange/tweeter baffle is passively isolated how much of a problem is movement due to internal pressure on the rear of the baffle? If it is significant what are the better ways to address it?
Given the tweeter/midrange cabinet will inevitably have driven modes/resonances what is an effective and practical way to damp and/or isolate in the presence of waveguides and without?
With a midrange and tweeter moving pistonically and mounted on a rigid flat baffle how well can the radiation pattern be controlled with an active crossover and a passive crossover?
If the midrange is not moving pistonically can the radiation pattern be improved significantly?
Would a 4 way on a flat baffle bring significant improvements? If so, and there is interest, would it fit?
Waveguides can control the radiation pattern better but require more effort to design. Apart from how to accomodate them physically and possible vibration issues it may be wiser to push their detailed consideration to a later stage. Unless some people wish to concentrate on just this aspect of course.
Port shape and placement options.
Pros and cons of a 12" woofer and a 10" woofer.
Is sealed a viable option without sub support?
Possible stand to minimise driving a suspended floor.
I will certainly have missed some relevant issuse. Suggestions?
Sort out how to organise, collect and share the work on the project.
Collect a list of similar speakers for guidance on technical and aesthetic aspects and to measure performance against.
Given the baffle will be wide what are the pros and cons of a minimum reasonable width or a significantly wider one?
For a wide baffle and optionally waveguides are the technical disadvantages of sharp baffle edges significant?
Is it viable to stiffen the woofer cabinet sufficiently to raise the frequency of the lowest mode/resonance of significance (i.e. driven and radiating towards the listener) above the passband of the woofer? If not, what is an effective way to damp the significant modes/resonances and/or reduce the amount they are driven.
How beneficial is passive isolation of the midrange/tweeter baffle from the woofer structure?
If the midrange/tweeter baffle is passively isolated how much of a problem is movement due to internal pressure on the rear of the baffle? If it is significant what are the better ways to address it?
Given the tweeter/midrange cabinet will inevitably have driven modes/resonances what is an effective and practical way to damp and/or isolate in the presence of waveguides and without?
With a midrange and tweeter moving pistonically and mounted on a rigid flat baffle how well can the radiation pattern be controlled with an active crossover and a passive crossover?
If the midrange is not moving pistonically can the radiation pattern be improved significantly?
Would a 4 way on a flat baffle bring significant improvements? If so, and there is interest, would it fit?
Waveguides can control the radiation pattern better but require more effort to design. Apart from how to accomodate them physically and possible vibration issues it may be wiser to push their detailed consideration to a later stage. Unless some people wish to concentrate on just this aspect of course.
Port shape and placement options.
Pros and cons of a 12" woofer and a 10" woofer.
Is sealed a viable option without sub support?
Possible stand to minimise driving a suspended floor.
I will certainly have missed some relevant issuse. Suggestions?
JBL L100 (the orginal) and JBL 4313 certainly also fit the description of the classic ones.
Thanks. I originally included a few 70s classics but removed them because the old types of drivers and loadings like acoustic suspension and aperiodic vents meant they weren't particularly relevant technically to a DIY build today. The classics listed are current speakers. The K&H was discontinued a while back but is technically relevant. However, the aesthetics of 70s speakers may be relevant for some of us and so perhaps I was wrong and a few classics would be useful.
They will be the same. As suggested earlier, it's conceptually possible to reduce the crossover to response targets that can be achieved either way.
Not electrically. Breakup is best avoided.
andy19191 wants to build a speaker that he wanted as a young person, which is admirable. I won't be building along. I can offer a survey of the what has been done in the past and what is being done in the present or future, which may serve, perhaps somewhat a performance metric.
The concept of big 3 way speakers never went away.
I believe the science has continues to better understood, the manufacturing has been streamlined (mass production) and using newer technologies (formed & reinforced plastics for increased internal volume to external volume ratio, easy cabinet / waveguide shape optimisation, built in equalisation, amplification, wireless audio)
They live on in modern equivalent as the the "Partybox"
Exhibit A:
JBL Partybox 1000
Dimensions (cm) 39.7 x 39 x 105 =162 L (external); 15.6 x 15.3 x 43.3 in = 6 cu ft (external)
Weight 34.7kg =76.5 lbs
Driver complement: 12" woofer (down firing, ported), 2 x 7" midrange, 1 compression driver
F6- 28Hz
Max SPL before compression limiting:
~99dB <160Hz, 109dB >160Hz
Price = $2,000 a pair
Sound:
Reference:
Exhibit B: Sony ULT Tower 10
Dimensions: 41.8 x 42.8 x 110.6 cm= 197 L (external); 16.8 x 16.5 x 43.5 in =7 cu ft (external)
Driver complement: 12.5" woofer (square), 3.5" midrange x 2 (L/R), 1.5" tweeter x2 (L/R), 1.5" rear tweeter x2
I have heard these speakers, and I must say, I was impressed. Sure, US $2000/pair today for the average young person is a high price.
But that is about US$250 in 1970 money... and about how much the JBL 100 was in 1970 ($273)
The concept of big 3 way speakers never went away.
I believe the science has continues to better understood, the manufacturing has been streamlined (mass production) and using newer technologies (formed & reinforced plastics for increased internal volume to external volume ratio, easy cabinet / waveguide shape optimisation, built in equalisation, amplification, wireless audio)
They live on in modern equivalent as the the "Partybox"
Exhibit A:
JBL Partybox 1000
Dimensions (cm) 39.7 x 39 x 105 =162 L (external); 15.6 x 15.3 x 43.3 in = 6 cu ft (external)
Weight 34.7kg =76.5 lbs
Driver complement: 12" woofer (down firing, ported), 2 x 7" midrange, 1 compression driver
F6- 28Hz
Max SPL before compression limiting:
~99dB <160Hz, 109dB >160Hz
Price = $2,000 a pair
Sound:
Reference:
Reference: https://www.jbl.com/party-speakers/JBLPARTYBOX1000.html
Modern review: https://www.rtings.com/speaker/reviews/jbl/partybox-1000
Modern review: https://www.rtings.com/speaker/reviews/jbl/partybox-1000
Exhibit B: Sony ULT Tower 10
Dimensions: 41.8 x 42.8 x 110.6 cm= 197 L (external); 16.8 x 16.5 x 43.5 in =7 cu ft (external)
Driver complement: 12.5" woofer (square), 3.5" midrange x 2 (L/R), 1.5" tweeter x2 (L/R), 1.5" rear tweeter x2
I have heard these speakers, and I must say, I was impressed. Sure, US $2000/pair today for the average young person is a high price.
But that is about US$250 in 1970 money... and about how much the JBL 100 was in 1970 ($273)
Reference:
https://www.kenrockwell.com/audio/jbl/l100.htm
https://www.kenrockwell.com/audio/jbl/l100.htm
In a crossover region a passive crossover will be summing the output from a larger driver falling off constantly at 6, 12, 18,... dB/octave with frequency and a smaller driver rising at 6, 12, 18,... dB/octave with frequency resulting in something of stepped constantish beamwidth. A DSP crossover can vary the rate of descent/rise with frequency to whatever is wanted in order to better control how the the two sources sum and hence how the beamwidth varies with frequency. The task is to quantify how significant the advanate is for our 3 way case.
As a soft cone starts to bend it changes the radiation pattern. Generally the change is an improvement though it depends on what is trying to be achieved. The task was to get a feel and quantify to some extent the signficance of the effect for our case.
That's the most interesting part of the design. You can offset or center the tweeter/mid. A thin sheet of 1/8th plywood attached with an always-wet adhesive can hide the modular element.
edit: changed my mind. I'd probably want to see the modular element.
A passive crossover does not have that limitation. For example, when I converted one of my previous speakers from passive to active, they were already all they could be so I was able to achieve the same level of performance. To show what was possible, here's a shot of the crossover.
It might be seen that way if you have no other way to produce the highs. The benefit of multi-way is we can avoid the issue altogether.
You'll find that crossing to a waveguide is a balance of avoiding breakup and allowing large source lobing.
Single driver lobing is the other reason not to take woofers too high.
When collocated at the two main positions I believe it only counts as one sub. Does that mean you should reduce the woofer to a 10" since you are combining the output with multisub?
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Yes, Allen is right. I have found it is possible to create a passive 2nd order low-Q electrical filter that is applied to a drivers natural response, and the result is a final filter that initially looks like a first order or very low Q second order, but further on transitions into 4th order.
This will be challenging. There will be a continuous stream of comments in this thread in addition to the more serious contributions. One idea is numbered trade studies. When someone posts a concept/design feature that is supported by analysis/simulation/empirical data, it is assigned a number or label. This way it can be referenced in the future, even after thousands of posts. There could be an index in the first post with links to all the trade studies.
I think you will also need to keep track of the design decisions that have been made, otherwise the team will keep churning and re-working issues that have already been settled. One of the most difficult challenges of managing an engineering team is keeping the members focused and on track, but also knowing when it is necessary to go back and redo and analysis or reevaluate a prior decision. Good Luck !
VituixCad baffle simulations are helpful here, especially with non-waveguide drivers. The ATH software can be used to generate polar responses that can feed into VituixCad.
There has been some information on this in the ATH4 thread. What has been done is probably not completely applicable to this design, but it shows what can be done and how to do it.
This is an area where you will probably do much of the heavy lifting 🙂
I would try to recruit someone with expertise in this area to your project. I don't think it can be pushed off too far into a later stage. Managing the directivity performance happens fairly early in the design process.
funnily, we all forgot this one : zaph sb 12.3 ... total monkey coffin... almost gorilla's ! http://www.zaphaudio.com/SB12.3/
https://www.madisoundspeakerstore.com/3-way-speaker-kits/zaph|audio-sb12.3-sb-acoustics-12-dual-midrange-3-way/?srsltid=AfmBOooZWdd-wvYBV3fzTA5SgKn4GPtJj8wr0PXKxMN69MOMcYmDbLbe
https://www.madisoundspeakerstore.com/3-way-speaker-kits/zaph|audio-sb12.3-sb-acoustics-12-dual-midrange-3-way/?srsltid=AfmBOooZWdd-wvYBV3fzTA5SgKn4GPtJj8wr0PXKxMN69MOMcYmDbLbe
I don't think you can count this as what Andy wants, this is not wide baffle, add not direct radiating big cone woofer, this is a modern slim tower speaker that looks awfull in my opinion. They are a modern evolution of the old JBL party speakers, but they are not the same. And they don't sound that good neighter i think. JBL makes great speakers, but this is (from my perspective at least) certainly not one of them...
If you want a modern style variation of it, look at what he mention as references. JBL still makes a (not so good) version of the L100, called the L100 Classic MKII that is more the layout and style that Andy wants. But then build with modern drivers and tech behind it.
The task was to quantify the advantage of a DSP crossovers like this to control radiation patterns in comparison with what can be achieved with practical passive crossovers. Supporting both analogue and digital crossovers within the same project will hopefully enable other differences to be quantified in a way that is useful for DIYers.
Very wise. Getting it right in the sense of adding flexibility and improving the technical performance of the cabinet may be a challenge. Implementation so that it is reliable will also have it's challenges. Nonetheless there is experience around with what has and has not worked well with removable baffles to draw on.
I don't understand the reasoning.
Discussion can obviously take place here. I think we need to collect the results of studies and longer pieces of text in a single browsable location. Github or something similar can help here. Writing notes and plots in markdown will enable web pages to be automatically generated for browsing. Quarto or similar can organise the markdown text into a structure. Git can track the changes. Python scripts can enable the sharing of small parameterised calculations. It looks reasonably doable but I am not speaking from experience though there is of course a fair amount of experience around on this sort of thing.
The idea could be to first to sort out the woofer chassis with a straightforward mid and tweeter combination that is of interest. For example a 5" midrange and tweeter with integral waveguide on a flat baffle. I suspect this is what a fair few would like from a project like this. Others may want to get involved with designing and manufacturing waveguides in order to gain a bit of performance. If we stick to standard range drivers and can sort out removable half baffle some of us could justify both particularly if they already have suitable drivers sitting unused on a shelf.
