@diyiggy BTW Parts Express is going to once again stock the NE149W and others in this family. This is really good news. What a great cone midrange.
In my opinion, this kind project must start with a rough idea of size and bass extension (F3/F6). Once we have decided on box size and the desired bass extension, we have, for the most part, defined the efficiency and sensitivity. We can also at this point make a rough estimate of the lower limit of cost, in other words, the three drivers will probably cost at least this x amount.
So if you are going to do a poll, I would start by polling people for their preferred size. It seems we have broad general agreement on bass extension, "about 40 Hz"... although I think some of us might mean an F3 of 40 Hz, while others might mean flat to 40 (which would mean an F3 of about 34 Hz), so we should clarify that.
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Regarding the discussion about a 12" woofer combined with a 5" mid. Based on my recent experience, I would say that a typical 5" midrange or midwoofer would be able to keep up with a sealed box 12" woofer if crossed at 300 Hz or higher. But if the 12" is bass reflex, then the added SPL capability of the woofer will result in the 5" mid being the limiting driver. This might be fine, but it is something to think about. If the crossover point is raised to 400 or 500 hz, this helps the midrange driver of course, but now the selection of potential 12" woofers has shrunk, and the price range has gone up as well.
If the mid is a 6" - 6.5" driver, then this has implications for the tweeter. This decision point probably drives us to using a waveguide in order to achieve an acceptable directivity pattern.
So if you are going to do a poll, I would start by polling people for their preferred size. It seems we have broad general agreement on bass extension, "about 40 Hz"... although I think some of us might mean an F3 of 40 Hz, while others might mean flat to 40 (which would mean an F3 of about 34 Hz), so we should clarify that.
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Regarding the discussion about a 12" woofer combined with a 5" mid. Based on my recent experience, I would say that a typical 5" midrange or midwoofer would be able to keep up with a sealed box 12" woofer if crossed at 300 Hz or higher. But if the 12" is bass reflex, then the added SPL capability of the woofer will result in the 5" mid being the limiting driver. This might be fine, but it is something to think about. If the crossover point is raised to 400 or 500 hz, this helps the midrange driver of course, but now the selection of potential 12" woofers has shrunk, and the price range has gone up as well.
If the mid is a 6" - 6.5" driver, then this has implications for the tweeter. This decision point probably drives us to using a waveguide in order to achieve an acceptable directivity pattern.
Yeah, seems Peereless is comming back or at least distributors see an interests from their customers. The corrundum tweeters are comming back in June at a webshop in Europe too where I purchased my 4 x NE149WE.
A budget range is important and is best made clear from the start. The OSMC project ended up using a pair of 3" midrange drivers that cost £1350. If the budget had been clear from the start I and I suspect a fair few others would have taken little interest. The budget I am proposing in the OP is £500-£1000 for all drivers. This makes it clear that it is not a project for those that place high value in the use of premium/prestige/boutique drivers nor is it a project for those that place high value in keeping the cost to a minimum. It is a project aimed at using good design to maximise the performance with standard range drivers.
PS Someone earlier mentioned the first post could be edited which is useful for sorting out which objectives have been reasonably settled and which have not. At this early stage pretty much everything is subject to change so if you disagree with an objective please post. One that is settled is that expensive drivers are out. The degree to which budget drivers are in is open to discussion.
May I ask, what price range roughly, in your opinion, does qualify as cost-effective for drivers only?
Would you be interested in building one, assuming every aspect were to your liking?
That is a very realistic budget. It does not overly constrain the selection of available drivers. For a 10" 3-way using good quality (but not boutique) drivers, the minimum possible cost is about $500 for all 6 drivers.
Andy - as the leader of this project, perhaps you should propose some guidance on maximum cabinet size.
j.
could be ussefull to chose them in order to reduce the slopes of the filter for 12db electrical to avoid too much coils like in the OSMC.
I don't treat them any differently, and I expect the same level of performance with any appropriate selection. There seems to be an assumption that expensive drivers are easier to work with, but how so? When you don't leave anything to chance when designing you'll put the same work in either way.
Changing peoples conceptions may be more the challenge.
In that case there should be a separate thread, a budget friendlier version. I just have no clue who would
like to volunteer as a speaker designer.
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Faital 12fe330 (Dayton DC300) / ScanSpeak d76 / SBA sb26stwg fit the 600€ budget, but Cabinet volume is bigger than the 12rs430 even if this costs about 200€ each.
Questions:
Dome or cone mid?
Which project parameters of the OSMC do we want to retain? Sensitivity, easy load, simplicity of construction?
Questions:
Dome or cone mid?
Which project parameters of the OSMC do we want to retain? Sensitivity, easy load, simplicity of construction?
Yes we could go with a tight budget of £500 for the drivers but the project would then be leaning into minimising cost rather than raising performance with design. It could also be combined with the objective of being simple to build. Balanced looking project but is it what people want to commit to? Personally I favour being less constrained by budget in order to widen what might be done with design which is my main interest. The standard range drivers I used for a rough costing (12" woofer, 5" midrange, 1" waveguide tweeter) came to £755.10. £500 seems doable, £1000 seems a reasonable stretch.
As others have suggested a poll is likely to be useful if we can sort out a useful set of questions:
I am the OP because nobody else in the OSMC thread started a new thread to discuss the topic. I seem to be leading the discussion but not sure about leading the project which will depend on how it evolves and what people wish to commit to.
I suggested a size of 50-100 litres in the OP to cover 10" sealed to 12" ported. I would suggest minimizing size isn't a strong objective but beyond 100 litres is more of a floorstander than a monitor.
Definitely. Love the idea of this project. It would be a great collab from this great forum. OSMC is awesome, but...really expensive.
Ballpark in reality, up to $100ish for tweeter (not $200), up to $150ish for mid (not $300), around $200ish for woofer (not $300).
I agree with @hifijim : some performance targets might be helpful, sealed/ported, spl, even directivity to a certain angle, sensitivity, minimum and nominal impedance. With the driver price ballparks, this will help narrow down all the driver choices a lot. I also presume we are talking a passive speaker; not dsp.
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No, I have not, because I don't know the TB line and actually I have not listened to a speaker with these drivers. Anyway, that mid seems interesting: Fs is lower than the Satori and the CSD is better.
I think $500 in drivers is not hard, $600 is getting easy. $50-$75 tweeter. $50-$100 midrange. $80-$200 woofer.
The woofer is going to be the most important driver because it is the most expensive and will determine the low frequency extension.
The items below are not independent, what else would need to be known?
Target cabinet size:
Maximum acceptable F3:
Peak SPL:
Sensitivity:
Nominal impedance:
The woofer is going to be the most important driver because it is the most expensive and will determine the low frequency extension.
The items below are not independent, what else would need to be known?
Target cabinet size:
Maximum acceptable F3:
Peak SPL:
Sensitivity:
Nominal impedance:
I am not sure I would do it that way again but I did a (edge) diffraction simulation in Vituixcad using the semi infinite baffle manufacturers measurements and these were the position where the diffraction were at a minimum. Having square edges does not help.
Ok, this is helpful. We are circling around to useful starting point.
Box size: 50 - 100 liter internal
Form Factor: large stand-mounted "bookshelf"
Woofer size: 10" - 12"
Driver cost: 500-1000 GBP ($625-$1250 USD).
Target F3: 40 Hz max, lower is better
I think I understand what you are getting at. Are you proposing that the project should maximize the use of analytic and empirical optimization, while minimizing the use of subjective decision making? Or am I misunderstanding you?
If so, I think that is a worthwhile objective.
j.
I concur. Furthermore, the directivity is "baked-in" by the cabinet shape.
In my speaker that had square edges and no round-overs, and 6" midrange driver, the cabinet didn't have traditional diffraction control ie. roundovers.
Initially the speaker started with a 26mm dome tweeter. But I ended up using a Ring Radiator. It had the unexpected (to me, at least) characteristic of some improved directivity control around 10KHz and above.
Scan-Speak D2604/8330 on 20x30cm cabinet, slightly off-set:
Scan-Speak R2604/8330 on same cabinet
In listening I found the Ring Radiator sounded much clearer, "less confused", or more relaxed.
Is this better than a shaped optimized cabinet and a "real waveguide". Certainly not. But if cabinet shape/waveguide optimization is something that the cabinet maker can't/doesn't want to do, it is an option.
I wonder whether the OSMC also has such smooth directivity through the use of the ring radiator Scan-Speak R2904/700000. Also another cabinet that was easy to build without large round-overs or facets. Oh, and nice driver- looks and feels like a jewel.
I believe a better option for those who are unable to build a complex baffle is the waveguide and/or 3D printed piece OVER the baffle.
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