Greetings all! My first post here after a couple of weeks lurking.
I can't tell if this belongs more in the Full Range Forum or in the Multi-Way Forum. FAST-builds seems to belong to Full Range if I am to take older threads as a guidance. And this is mainly about a FAST idea. For now.
Mod may correct me if I placed this thread in the wrong place.
Background:
I am thinking about building my first serious speaker build since none of the speakers I've heard in my price range seems to fit my taste. I have only built some boomboxes earlier with focus on the highest amount of hours with "decent" quality music per kilogram of speaker/battery. So my experience is limited.
I have noticed that I am more fond of the sound in more vintage speakers. As I try to analyze what it is I like with the old speakers I've tried I conclude that it has to be good transient response and low directionality. My small 70's speakers seems to fill the room a lot better than my Dynavoice Audience 72's no matter what the position. I've tried several other modern speakers with the same result. The modern speakers including the Dynavoices sounds cleaner and all that. In most ways of looking at it they sound objectively better. But there isn't as much life in them as I'd like. Some modern sealed or full range speakers have been more appealing. That got me thinkin.
Problem, and solution?
As I read about different types of designs, problems with crossovers and so on I come to some conclusions. I figure that I don't want steep crossovers, since phase change seems to be one of the factors that takes the liveliness out of the sound. And with my very limited knowledge I wont be able to come around that with steep crossovers. Not in my first build. Furthermore I don't want a XO at frequencies around 1000-5000Hz since this is where the ears are most sensitive (sources varies about exact frequencies). Ordinary 2-way speakers are thus already ruled out. So I started looking at the possibility of making a 3-way with 1st order crossovers with crossing points outside the 1000-5000Hz range. Seems hardly possible at all. If it's possible to make anyting good with these criteria it will demand a full range driver. So I started looking at a solution with a full range driver doing the most work with only a little help in the frequencies it can't handle well, since I do want relatively deep bass. And after reading, learning and revising my plans for a week I find out that the concept I am thinking on already has a name. FAST!
But?
But. Is the FAST design right for me? The thing is this, I do not want an XO between 1000 and 5000Hz or steep XO's for a reason. And for the same reason I might want a tweeter. A 3" driver will start to gain directionality in frequencies above roughly 2500Hz, a bigger driver even before that. As I understand it directionality kills the ability to fill the room. The vintage speakers I like seems to have been focused on avoiding this, particulary in the treble. I also read at several places in this forum that people who have loved to play around with FAST designs still get tired of them. Might a flat feeling in the treble be responsible?
How much would you guys with experience with FAST say this matters?
Different woofer solution?
And then comes the problem with the woofer. I want really fast transient response. Not only to have a dry hard bass, but I want the bass to fit exactly with the mids where it is supposed to. So, I am looking at a sealed woofer that isn't to flobby and that can handle quite high frequencies, since I want a first order crossover. Quite obviously this will mean that the bass won't go to deep. I have always found myself liking the sound of sealed woofers more than vented ones. So I have to make it work as good as possible.
But I have an Idea, and I like to hear opinions. Similar to 2.5-Way speakers I am thiniking about two or more identical woofers with different crossovers. Simply adding more woofers will only increase the volume. But if a second and potentially a third woofer is filtered to only help in the frequencies where the first one already has begun to drop in power. Will that help to extend the bass further down without sacrificing transient response? What are the drawbacks? Will phase shifting become a problem close to the resonance frequency if a first order low pass filter is deployed at this range? I am thinking of a Q around 0.5, not only for the sake of the transient response, but because of a slightly earlier, but softer, roll off might fit good with this approach if it works.
Right know I am thinking of a FaitalPro 3FE22 8Ω and a XO at 400-600Hz, or possibly higher since I want 1st order filters. I am thinking of building filters accessible from the back and seperate enclosures for the different drivers. So that I can change one part at a time easily during the experimental phase. Should I give up on the 1st order XO's right now?
I expect to be wrong in a lot, so please correct me. If you will take your time to guide me I would be very grateful.
I can't tell if this belongs more in the Full Range Forum or in the Multi-Way Forum. FAST-builds seems to belong to Full Range if I am to take older threads as a guidance. And this is mainly about a FAST idea. For now.
Mod may correct me if I placed this thread in the wrong place.
Background:
I am thinking about building my first serious speaker build since none of the speakers I've heard in my price range seems to fit my taste. I have only built some boomboxes earlier with focus on the highest amount of hours with "decent" quality music per kilogram of speaker/battery. So my experience is limited.
I have noticed that I am more fond of the sound in more vintage speakers. As I try to analyze what it is I like with the old speakers I've tried I conclude that it has to be good transient response and low directionality. My small 70's speakers seems to fill the room a lot better than my Dynavoice Audience 72's no matter what the position. I've tried several other modern speakers with the same result. The modern speakers including the Dynavoices sounds cleaner and all that. In most ways of looking at it they sound objectively better. But there isn't as much life in them as I'd like. Some modern sealed or full range speakers have been more appealing. That got me thinkin.
Problem, and solution?
As I read about different types of designs, problems with crossovers and so on I come to some conclusions. I figure that I don't want steep crossovers, since phase change seems to be one of the factors that takes the liveliness out of the sound. And with my very limited knowledge I wont be able to come around that with steep crossovers. Not in my first build. Furthermore I don't want a XO at frequencies around 1000-5000Hz since this is where the ears are most sensitive (sources varies about exact frequencies). Ordinary 2-way speakers are thus already ruled out. So I started looking at the possibility of making a 3-way with 1st order crossovers with crossing points outside the 1000-5000Hz range. Seems hardly possible at all. If it's possible to make anyting good with these criteria it will demand a full range driver. So I started looking at a solution with a full range driver doing the most work with only a little help in the frequencies it can't handle well, since I do want relatively deep bass. And after reading, learning and revising my plans for a week I find out that the concept I am thinking on already has a name. FAST!
But?
But. Is the FAST design right for me? The thing is this, I do not want an XO between 1000 and 5000Hz or steep XO's for a reason. And for the same reason I might want a tweeter. A 3" driver will start to gain directionality in frequencies above roughly 2500Hz, a bigger driver even before that. As I understand it directionality kills the ability to fill the room. The vintage speakers I like seems to have been focused on avoiding this, particulary in the treble. I also read at several places in this forum that people who have loved to play around with FAST designs still get tired of them. Might a flat feeling in the treble be responsible?
How much would you guys with experience with FAST say this matters?
Different woofer solution?
And then comes the problem with the woofer. I want really fast transient response. Not only to have a dry hard bass, but I want the bass to fit exactly with the mids where it is supposed to. So, I am looking at a sealed woofer that isn't to flobby and that can handle quite high frequencies, since I want a first order crossover. Quite obviously this will mean that the bass won't go to deep. I have always found myself liking the sound of sealed woofers more than vented ones. So I have to make it work as good as possible.
But I have an Idea, and I like to hear opinions. Similar to 2.5-Way speakers I am thiniking about two or more identical woofers with different crossovers. Simply adding more woofers will only increase the volume. But if a second and potentially a third woofer is filtered to only help in the frequencies where the first one already has begun to drop in power. Will that help to extend the bass further down without sacrificing transient response? What are the drawbacks? Will phase shifting become a problem close to the resonance frequency if a first order low pass filter is deployed at this range? I am thinking of a Q around 0.5, not only for the sake of the transient response, but because of a slightly earlier, but softer, roll off might fit good with this approach if it works.
Right know I am thinking of a FaitalPro 3FE22 8Ω and a XO at 400-600Hz, or possibly higher since I want 1st order filters. I am thinking of building filters accessible from the back and seperate enclosures for the different drivers. So that I can change one part at a time easily during the experimental phase. Should I give up on the 1st order XO's right now?
I expect to be wrong in a lot, so please correct me. If you will take your time to guide me I would be very grateful.
At a glance, 'sounds' like you ideally want a modern version of the pioneers of audio's original two way cinema/studio monitor except with a small [2"?] 'FR' driver in a large WG in lieu of a compression loaded exponential horn, coupled to essentially a near full-range woofer designed for 'full range' consoles up into the '60s even though XO'd < 1 kHz or > 5 kHz.
They concluded that a 12" with a ~12.5 kHz usable top end for use with no XO and a horn designed for 800 Hz/2nd order just capped off way up high, making it essentially just a WG, was the best overall compromise, creating a monitor that today is worth a decent 'nest egg' if one ever comes up for sale.
MCM sold slightly more modern replicas of this 12" for many years as a 'dirt cheap' ~universal replacement, but sadly it finally was sold off when folks no longer felt the need for such an adaptable driver. I just wish I'd known about it in time to get some more as it was the foundation of most of my 'for barter' tower/column speakers [aka MLTL].
Today, about the closest type is likely to come to it will be a pair of vintage organ drivers AFAIK, so good luck with that as I imagine they're pretty scarce nowadays too.
In short, and as I understand your ideal goal, not going to happen in a 2 way, so as you surmised it's got to be at least a 2.5 way and though the pioneers had no need for a .5 woofer's extra BW, they felt that since the mean acoustic power point was 500 Hz [back then], a 3 way broken up into decades was the best overall compromise, so made 500, 5 kHz the XO points.
Converting these to 1st order XO's presents some serious challenges beyond the scope of the typical DIYer's skills/tools if one is to keep them the ideal > -24 dB points out of the 1-5 kHz BW, so where to compromise? That's for you to decide.
AFAIK, cascading woofers require steep XOs, digital TD, EQ, phase correction to meet your in room transient response goals.
Personally, and all things considered, this is what large Synergy concept horn systems are for, coupled to separate suitably powerful [infra, sub] bass systems XO'd < 80-100 Hz/4th order.
GM
They concluded that a 12" with a ~12.5 kHz usable top end for use with no XO and a horn designed for 800 Hz/2nd order just capped off way up high, making it essentially just a WG, was the best overall compromise, creating a monitor that today is worth a decent 'nest egg' if one ever comes up for sale.
MCM sold slightly more modern replicas of this 12" for many years as a 'dirt cheap' ~universal replacement, but sadly it finally was sold off when folks no longer felt the need for such an adaptable driver. I just wish I'd known about it in time to get some more as it was the foundation of most of my 'for barter' tower/column speakers [aka MLTL].
Today, about the closest type is likely to come to it will be a pair of vintage organ drivers AFAIK, so good luck with that as I imagine they're pretty scarce nowadays too.
In short, and as I understand your ideal goal, not going to happen in a 2 way, so as you surmised it's got to be at least a 2.5 way and though the pioneers had no need for a .5 woofer's extra BW, they felt that since the mean acoustic power point was 500 Hz [back then], a 3 way broken up into decades was the best overall compromise, so made 500, 5 kHz the XO points.
Converting these to 1st order XO's presents some serious challenges beyond the scope of the typical DIYer's skills/tools if one is to keep them the ideal > -24 dB points out of the 1-5 kHz BW, so where to compromise? That's for you to decide.
AFAIK, cascading woofers require steep XOs, digital TD, EQ, phase correction to meet your in room transient response goals.
Personally, and all things considered, this is what large Synergy concept horn systems are for, coupled to separate suitably powerful [infra, sub] bass systems XO'd < 80-100 Hz/4th order.
GM
I have the 3fe25 ferrite version. It sounds awesome, pretty similar to the neo version if memory of xrk's full range speaker shootout serves me. I run it without any filter at all and it sounds just fine. I have a sub amp I could run it out of that would filter it around 200 but I haven't even found it necessary to tinker with that yet.
If you want good dispersion, the 2.5" SB acoustics sounds good as well. Theoretically it should have better dispersion as it is smaller right.
I can't help much with the technical stuff, but I would recommend either of the 3fe's. Check out the older threads of full range comparo's xrk71 did and you can hear several.
If you want good dispersion, the 2.5" SB acoustics sounds good as well. Theoretically it should have better dispersion as it is smaller right.
I can't help much with the technical stuff, but I would recommend either of the 3fe's. Check out the older threads of full range comparo's xrk71 did and you can hear several.
1st order of business: we are trying to lose the term FAST, which is fairly disliked, and use the term WAW (Woofer Assisted Wideband).
There is a lot of room that has yet been explored with WAWs. The concept turns the conventional 2-way on its head, using a FR as a midTweeter for 5-6 octaves, and helper woofers for the rest (instead of tweeters for 2-3 octaves and woofers for the rest.
Take a good FR — the Faital has good cred, but i haven’t tried it yet — and mate with helper woofers. With the huge number of midBasses designed for normal 2-ways, there is lots of choice. Since it won’t be used where it is most ragged one really only needs concern themselves with whether the bass driver has the appropriate combination of bass extention in the size box you can live with, cost, and if you plan a passive XO bass sensitivity. You want to search for a woofer that will work sealed.
500-5kHz or so is more like the critical band, i like to try to keep the XO below 400Hz. One can usually choose drivers & box such that one can get away with 1st order. And it also ensures that the driver centre-centre can be kept at under a quarter wavelength.
XO is much easier, and the system less pricey, if you go active. With carful design you can use a PLLXO which costs very little and adds no electronic haze. The HP filter value is dependent on the amplifier used for the high range.
HF dispersion is very dependent on the driver you choose. You cannot reply on the “general” formula which is based on a flat stiff diaphragm.
We have done a number of WAW, only one sealed.
P10-hifi Alpair 7.3eN + SDX7eN WAW (aka FAST)
With the width of the box we were able to push the XO down to 180 Hz.
dave
There is a lot of room that has yet been explored with WAWs. The concept turns the conventional 2-way on its head, using a FR as a midTweeter for 5-6 octaves, and helper woofers for the rest (instead of tweeters for 2-3 octaves and woofers for the rest.
Take a good FR — the Faital has good cred, but i haven’t tried it yet — and mate with helper woofers. With the huge number of midBasses designed for normal 2-ways, there is lots of choice. Since it won’t be used where it is most ragged one really only needs concern themselves with whether the bass driver has the appropriate combination of bass extention in the size box you can live with, cost, and if you plan a passive XO bass sensitivity. You want to search for a woofer that will work sealed.
500-5kHz or so is more like the critical band, i like to try to keep the XO below 400Hz. One can usually choose drivers & box such that one can get away with 1st order. And it also ensures that the driver centre-centre can be kept at under a quarter wavelength.
XO is much easier, and the system less pricey, if you go active. With carful design you can use a PLLXO which costs very little and adds no electronic haze. The HP filter value is dependent on the amplifier used for the high range.
HF dispersion is very dependent on the driver you choose. You cannot reply on the “general” formula which is based on a flat stiff diaphragm.
We have done a number of WAW, only one sealed.
P10-hifi Alpair 7.3eN + SDX7eN WAW (aka FAST)
With the width of the box we were able to push the XO down to 180 Hz.
dave
You might look here and get some ideas. I am pretty certain that the 3FE25 could be used here but with more padding (attenuation) to get it to level match the woofer after baffle step losses. However, using dual RS225-8’s in parallel will buy 6dB of sensitivity at same voltage and that would more closely level match the 3FE25. The passive XO would have to be redesigned, but I think it’s doable. 1st order XO around 600Hz to 900Hz.
http://www.diyaudio.com/forums/full...-rs225-8-fast-ref-monitor-95.html#post5305534
I haven't heard the Faitals, so can't speak directly to that, but I couldn't be happier with my Planet 10-designed Alpair 7.3/12pw WAW. If your wood working chops are up to the task, I have yet to hear anything that sounds better to my ears in my space with my amps. YMMV.
Build thread here:
Alpair 7.3eN/12pw WAW build
Build thread here:
Alpair 7.3eN/12pw WAW build
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fyi - not everyone. I prefer the term FAST as it has been in use for some time and sounds kinda sleek. I dislike the term WAW because it sounds lame in comparison with FAST......
For a first time speaker build my 2c:
Simplest is a single driver full range speaker, no cross over, no bi-amping and many good designs. My suggestion would be a MLTL such as the mini-Tower (mine is called Martello 2) or a Pencil design. Choose your driver carefully if you might have sensitivity to treble 'shout' as I do.
Next up is the traditional 6" woofer + 1" tweeter with a relatively simple cross-over; it's where much knowledge exists and plenty of parts available, even kits ready to build. There are reasons to criticise this approach but it's a great place to start and learn and many a 2-way has won the hearts of their owners.
FAST implies a lowish cross over frequency and this is often best served with bi-amping. Therefore, more complex for the first-timer but not necessarily more difficult to build.
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Do the -24 points also need to be outside the 500-5000Hz range to avoid the problems? I thought it was the area around the XO point that needed to be out of that range. Seems like that is almost impossible to get even with steep XO's and full range drivers. Even with a 4th order filter it has to begin its decline an entire octave up at 10000Hz.
About horns, I think they might be out of the question. I read some about horns in the past and built a folded Fostex-horn according to instructions once. I've also built a couple of simple TQWT designs. And to get low enough bass from the horn I can tell right now that I have to go a bit big to begin with, and the resonable sized ones I've heard haven't impressed much when it comes to correct and low bass. Better than the TQWT's that I've thought had a coloration to their sound. But that isn't much of a merit since the TQWT's was only playthings I've made for fun since the math is quite simple.
But, I realize now that just writing about why I don't think horns might be a good idea still made me consider them.
But, about the cascading woofers. I've never actually seen anyone ever write about the idea. I thought it was weird if I was the only one to get the idea. It would be hubris to think I would have uniqe ideas in an area far outside my expertise, but I still couldn't find any information about it. Google was "helpful" and tried to give me information on tons of other stuff even when I tried to specify my search. But now when you mention it as something that might be quite known, and even used the term I was about to use, "cascading woofers" I still get a bit hopeful even if I take your word for it being something hard to do succesfully. Do you know of anyone that has tried the design?
In your opinion, since my ideas isn't compatible with each other. Beside the cascade idea, which other ideas has to go as well? Should I forget about 1st order filters, forget about tweeter or both? Should I copy some already existing FAST build?
I have lurked a while and checked the comparisons already. And I think I pretty hooked on the idea with the 3FE22. As I understood it it was slightly better than the 3FE25 except in the lows, where I plan to have a woofer anyway. But thanks for the input. :)
Thanks, I shall see I am capable to get something useful from those graphs. Shall check that program out as well btw.
I've actually haven't checked out active XO's since I figured that was out of my league. But you make it sound like it's the other way around. So I shall research PLLXO a bit. But dependent on the amplifier? Why? Seems like it is complicating things.
Good point about the general formula for dispersion being an oversimplification. But won't a 3" driver of any shape begin to turn directional at higher frequencies anyway? Will a 3FE22 manage dispersion at high enough frequencies? When I read the response graph at 45 degrees it seems like it starts to loose dispersion a bit to early, but I don't know if dispersion matters much at these frequencies.
Nice build you've got there. Why did you push the XO's so low as 180Hz?
Thanks! I have been searching for suitable woofers, but I've missed that one since I was looking at matching the SPL a bit. But parallell is doable of course. :) But that build looks like something pretty close to what I want right now. :)
I'll look into that. Doesn't look to hard to manage the wood work with proper tools. It is vented. But maybe I am to hooked on building a sealed speaker.
I am not to keen to build a lot of different builds before going after what I actually want. Even if it means I'll miss out some of the experience.
Bi-amping might not be to much of a problem. But, why is bi-amping more important with low frequency XO's?
I like FAST for same reasons. Names have a way of sticking sometimes and besides it sounds way cooler than Waw, which sounds like an interrupted “what?”.
With that said, a first order high pass with a cap and low order first order low pass with a coil and some resistors to pad down the full range driver can be estimated quite effectively using Xsim and factory FRD and ZMA curves.
With that said, a first order high pass with a cap and low order first order low pass with a coil and some resistors to pad down the full range driver can be estimated quite effectively using Xsim and factory FRD and ZMA curves.
- hi X - wonder if my 30uF/1.5mH highpass and 4fe32 with 0.2 liter chamber would need much padding with Dayton's PA310-8 ? Faital's rating of 2.7 mm excursion shows >50 volts could be applied to the FR (hahaha) w/o exceeding xmax. Is there a good "1st" order solution with 4fe32? I don't like seeing cones move at high spl.
The HP is a single cap and uses the input resistance of the amplifier for the other half of the filter. So C depends on R.
TLS.org | Passive Line-Level Crossover
But some are better than others. And with many decent dispersion is happening up high. Typically a FR is designed such that the outside of the cone decouples from the inside of the cone and the radiating area at HF is smaller than the cone.
As a reference, have you ever looked at the dispersion of a typical 1” dome tweeter.
dave
yeah - 30uF/1.5mH - within the excursion limit if the voice coil could take it and not melt nor change resistance >56 volts. Qtc ~2, - filter Q ~0.5 (or less to compensate for unfiltered peaking) you can see the highpass gain is about -6 or 7dB @ 400Hz so compensates for the unfiltered peaking with 12.2 cubic inches tight back chamber = not much movement. Would it "sound" better on the highest spl peaks it could handle with a so called "1st order" passive highpass filter ? seems like that would take RLC Z nulling = more cost and still not "1st order"
I don't like "gargle" - that can be heard in some 15cx. A 4-way FLH speaker could be clean in that aspect
I don't like "gargle" - that can be heard in some 15cx. A 4-way FLH speaker could be clean in that aspect
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Well, you set the limits at 1-5 kHz and again, based on my understanding of how 'pure'/'clean' you want this BW, then according to my source it ideally needs to be -25 dB for us humans to not hear/perceive any overlapping bandwidth [BW], but what's a dB or two among friends, so rounded it up to the more common -24 dB?
Right, hence my rather negative outlook on your goals as you would need a super wide BW well beyond what any drivers can currently do kind of like for an amp to have flat amplitude and phase over 20-20 kHz requires a ~2-200 kHz BW IIRC.
What can I say? A synergy horn satisfies your performance goals in the 1-5 kHz BW and then some down to the bass BW and out to ~20 kHz and if woofer horns don't sound 'right' to you, then its corollary is OB/IB with [multiple] low Qt, high Vas drivers with IB being the pioneer's choice: https://i.pinimg.com/originals/b4/21/8c/b4218cfcd07d2a4a18390e08fc6108d1.jpg
Unfortunately between failing memory and most of my early tech 'library' locked up in a damaged HD, my go to example is lost, but it was a 'FR' driver and six? cascaded woofers designed specifically as part of a full on SET tube system with a very complex, high insertion loss passive XO system. By all accounts it was quite an 'enveloping' music system, but don't recall any DIYer copying it.
A more interesting one was RCA's early attempt to fill a cinema without horns 'on the cheap' since W.E. had a patent 'lock' on multiple complex horn systems. It was composed of a vertical array of independently suspended, XO'd 15" 'full range' woofers on both sides of the screen which could be physically 'aimed' in both planes in an attempt to get an acceptable power response over the entire audience. Of course it was a huge failure overall as among other things it couldn't generate enough sound power with the low power amps of the day compared to the super efficient horns. I haven't bothered to research the tech details of today's prosound line arrays, but assume they are all digitally cascaded to a greater or lesser degree depending on the needs of the app.
GM
After writing here and reading your answers I decided to research a bit more on my own. Then some work came up and I became busy with that for the past two weeks so it has been a while. But now I'm back with more questions. Hope you have patience with me and are able to help.
As I understood it the most important thing was to keep the crossover points and their immidiate vicinity outside the critical range. Some overlapping shouldn't be as much a problem as I understood it. But never mind. I've decided to not have a tweeter, at least for now.
As for now I have two alternatives in mind. A 3FE22 with a Beyma 10BR60-V2 or maybe its 12" brother in a sealed box, tuned for a low Qts at around 0.6 or maybe higher if I go with the 12". So the speaker will be big.
Or, if it's possible, with two or three Monacor SPH-220HQ if I can get the cascading thing to work. I have done some experimenting in XSim, and it's not hard to get it to work there. But I can't get XSim to consider the box. I also tried a program called Basta!, but Basta can't handle different filters for speakers in parallell in the same box. And Basta seems to give me a bump in response right below crossover frequency every time I add a low pass filter. So in Basta it's a mess. But at the same time I've heard that the program might have bugs so I don't want to trust it with anything. So I need a trustworthy program that can do both. Any suggestions?
I still haven't figured why it need steep crossovers. I have recently seen people mentioning an extra speaker giving a boost below the F3 point of their primary speaker. So now I know that people have done it.
Below are the simulation in XSim. The red speaker curve is unfiltered, and the Purple and Green curves are filtered with inductors at 25mH and 60mH respectively. Blue is total. I don't know if the Impedance is a problem. Never mind the jagged curve. It was a low resolution pic I made the ZMA form.
And below is the same configuration (with different colors) in Basta. It's a mess. I'm new to this so the bump maybe is what to expect with an LP filter? And the fact that Basta can't handle FRD or ZMA-files doesn't improve things.
In short. XSim and Basta gives me very mixed signals about the feasability of the project. And so does the internet.
Are there any objections to the alternative with the Beyma in a closed box with 1st order XO? In both alternatives i am thinking of putting the XO in a way to smooth out the baffle step. Also beveling the cabinet.
I've decided to go with passive crossovers since planning active crossover led me astray with more plans of investments than I can afford at the moment. It's better to get the hang of building basic speakers first and maybe consider other projects after that. I looked at the dispersions of small tweeters and they are definitiely a bit ahead of the 3FE22 in higher frequencies on paper. But also decided that 3FE22 probably is good enough. Worst case scenario I add a tweeter. I can build the speaker with that scenario in consideration from the beginning.
Well, you set the limits at 1-5 kHz and again, based on my understanding of how 'pure'/'clean' you want this BW, then according to my source it ideally needs to be -25 dB for us humans to not hear/perceive any overlapping bandwidth [BW], but what's a dB or two among friends, so rounded it up to the more common -24 dB?
Right, hence my rather negative outlook on your goals as you would need a super wide BW well beyond what any drivers can currently do kind of like for an amp to have flat amplitude and phase over 20-20 kHz requires a ~2-200 kHz BW IIRC.
What can I say? A synergy horn satisfies your performance goals in the 1-5 kHz BW and then some down to the bass BW and out to ~20 kHz and if woofer horns don't sound 'right' to you, then its corollary is OB/IB with [multiple] low Qt, high Vas drivers with IB being the pioneer's choice: https://i.pinimg.com/originals/b4/21/8c/b4218cfcd07d2a4a18390e08fc6108d1.jpg
Unfortunately between failing memory and most of my early tech 'library' locked up in a damaged HD, my go to example is lost, but it was a 'FR' driver and six? cascaded woofers designed specifically as part of a full on SET tube system with a very complex, high insertion loss passive XO system. By all accounts it was quite an 'enveloping' music system, but don't recall any DIYer copying it.
A more interesting one was RCA's early attempt to fill a cinema without horns 'on the cheap' since W.E. had a patent 'lock' on multiple complex horn systems. It was composed of a vertical array of independently suspended, XO'd 15" 'full range' woofers on both sides of the screen which could be physically 'aimed' in both planes in an attempt to get an acceptable power response over the entire audience. Of course it was a huge failure overall as among other things it couldn't generate enough sound power with the low power amps of the day compared to the super efficient horns. I haven't bothered to research the tech details of today's prosound line arrays, but assume they are all digitally cascaded to a greater or lesser degree depending on the needs of the app.
GM
As I understood it the most important thing was to keep the crossover points and their immidiate vicinity outside the critical range. Some overlapping shouldn't be as much a problem as I understood it. But never mind. I've decided to not have a tweeter, at least for now.
As for now I have two alternatives in mind. A 3FE22 with a Beyma 10BR60-V2 or maybe its 12" brother in a sealed box, tuned for a low Qts at around 0.6 or maybe higher if I go with the 12". So the speaker will be big.
Or, if it's possible, with two or three Monacor SPH-220HQ if I can get the cascading thing to work. I have done some experimenting in XSim, and it's not hard to get it to work there. But I can't get XSim to consider the box. I also tried a program called Basta!, but Basta can't handle different filters for speakers in parallell in the same box. And Basta seems to give me a bump in response right below crossover frequency every time I add a low pass filter. So in Basta it's a mess. But at the same time I've heard that the program might have bugs so I don't want to trust it with anything. So I need a trustworthy program that can do both. Any suggestions?
I still haven't figured why it need steep crossovers. I have recently seen people mentioning an extra speaker giving a boost below the F3 point of their primary speaker. So now I know that people have done it.
Below are the simulation in XSim. The red speaker curve is unfiltered, and the Purple and Green curves are filtered with inductors at 25mH and 60mH respectively. Blue is total. I don't know if the Impedance is a problem. Never mind the jagged curve. It was a low resolution pic I made the ZMA form.
And below is the same configuration (with different colors) in Basta. It's a mess. I'm new to this so the bump maybe is what to expect with an LP filter? And the fact that Basta can't handle FRD or ZMA-files doesn't improve things.
In short. XSim and Basta gives me very mixed signals about the feasability of the project. And so does the internet.
Are there any objections to the alternative with the Beyma in a closed box with 1st order XO? In both alternatives i am thinking of putting the XO in a way to smooth out the baffle step. Also beveling the cabinet.
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