thanks for your input, i will go with full Satori driver since it's originated in my country. inspired by Eaglestoneworks Viginti, configuration as below:
MR16P-8
TW29BN-4-B
MR16P-8
WO24P-8 x2
the option for midrange can be MR16 / MR13 or switch to MW series, i'll have to test later which one will match. i have a friend who has collections of Satori driver on his build, i will ask him to build the cabinet and borrow his driver for testing
I can use passive XO for mid-high where there are already many project outhere that can be used as starting point, and utilize my minidsp 2x4HD for woofer and upper section
Attachments
Why not? Lets take far fetched analog from some car sports with a short story shall we?
Alright, time to get a new car. What should I buy? I like to watch car sports on the TV and boy would like to participate, get some of that excitement! The cars look nice and fast but as I go to a sports car store and see the cars cost a lot. I've got a family, can't buy that, I'll just build my own!
Off to the internet and ordering some nice Racing Wheels and Biggest Racing motor I can barely afford to. Staking it all to the features that makes most sense with the amount of knowledge I've got from the television. Cool cool, of to the garage, wheels and the motor in to the chassis we also bought. The chassis looks similar as in TV. Got it from the dude living up the street. Nice price on that one and with the favorite color! Finished it with nice stripes. There wasn't quite enough paint but I think it is not going to affect the performance so I just finish it up with some other color.
I'm so excited about the car and have been living my dream for many track sessions, beating my own best laps every now and then! Nice!
Until a sports car enters the same track session and vanishes to horizon after few corners. What the hell?! I noticed it had a spoiler on the back! I'll just add one to mine and I should be on par! Fast forward. Checking back the track times there seems to be not much difference after getting the spoiler though, and the car feels a bit scketchy on high speed I think so it must have been the fact they use MobOil racing fuel! Yes, I'll start using that! But still quite can't get into corners like with the sports car.. I'll go and ask the sports car driver how he is so fast on the next track date! And the hobby sports car driver says something about the nice leather seats and complains there are some bright lights on the dash...
I've now quit the car sports since to get the performance was so hard and confusing. I have never noticed that in the car sports on the TV there is a team that has constantly won every race on this season, both team drivers win all the others hands down! The series is heavily regulated with max HP, engine displacement, total weight, make and model, all teams pretty much get the same recipe for their cars in order to bring forward the talent in the drivers. Never thought there probably some clever folks on the winning team that has been able to make the whole system work better than the others, all parts in the car and the driver and the pit stop team all work together for the wins. This would make the winning team as the reference for the others to beat. Getting the reference performance wasn't necessarily increased cost, just better balanced out system that got the top performance on this particular season within the particular sports car series.
---
Ok story over. How do you like the analog, a hifi race?
I don't follow car sports but have some hunch on it, how things might work just by thinking of how the stuff probably plays out simplified using imagination and reasoning on what I have seen on the television. And quite frankly found it quite funny to imagine our dude with his sports car on the track ripping nice personal bests having so much fun The dude in the story, and even the nice sports car driver he asked questions from, were into details instead of the whole system and just didn't know what they were doing. And I suspect even if both of the characters on the track session had cars borrowed directly from the leading sports car team, and got replaced by the team drivers, they probably still wouldn't reach lap times from the sports car series since rest of the team is on vacation and it is raining.
I encourage everyone to use their imagination and reasoning skills! Ask help from the brain like Homer does, because it is not too complicated to come up with good sounding speakers. I've managed to make some, and probably you, because all our self made stuff is best!!! as long as we don't compete and lose to something else it is like living a dream and lots of fun!
and it doesn't matter if we did because it is supposed to be fun hobby. Just don't be the dude throwing money on things without thinking what you actually need. If you wanna win, you can't afford to ignore any aspect that goes into performance, but also you don't have to implement everything. Just be aware where you are at and think what you need to have in order to get what you want to achieve with a system. The dude in the story wanted a race car but what he actually needed was a family saloon... And we shouldn't forget one can put nice wheels and motor to a family saloon too! Just don't expect it to win on a track day since the system is still for different application! In family application a reference car could be measured by cheapest operating cost vs. available space for example, or reliability. Almost opposite to racing.
ps. I'm not on the winning team because I mostly work alone but I'm also not the story dude since I know what my application is and I'm trying to work out a system, what is it and what goes into it and how it comes together. I'm not thinking drivers or motors or wheels themselves, I'm thinking the system I have come up with simple reasoning and imagination and the wheels and motors evolve as the system develops
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This post will get into loudspeakers a bit but lets stick with as less detail as possible. Some assumptions and minimal knowledge is mixed in helping reasoning to get us forward. A few more numbers from wavelengths to get started.
Human auditory perception is often mentioned to be about 20-20kHz so that would be the absolute maximum bandwidth we have to design a reproduction system for if seeking for good sound, a good speaker that doesn't take away. As mentioned earlier there is possibility to reduce the bandwidth requirements some depending on application and the listeners ability to perceive, and what the usual source material contains. But lets stick to the 20-20kHz for now.
Calculator gives wavelength for 20Hz roughly 17m and for 20kHz it is 1.7cm. 2kHz would be roughly 17cm and 200Hz in turn about 170cm. Now lets think about how the sizes relate to our daily lives. Starting from top of our target bandwidth the 20kHz is about the size of your belly button, 2kHz almost fits on palm of hand, 200Hz is a bit too big to hold on your lap comfortably and 20Hz needs a tennis court to fit, badminton court is not long enough, cheez!
Reasoning from this, even if we relaxed the extremes of our bandwidth requirement a bit, the wavelengts are so different in size at the extremes that covering that kind of a bandwidth would need at least 2-way system. I'm thinking of the nice high SPL requirement we have and directivity graphs found in the studies and mentioned earlier, that have been shown to give good listening impressions on blind listening tests, nice constant or at least smooth controlled directivity. We must need at least two transducers, big and small, since while one real world driver could do the whole bandwidth in paper the SPL capability of such system would be limited by the fact that low frequency SPL would benefit bigger cone area which in turn lowers frequency where high frequency beaming starts. It is a balancing act on any sized driver to have extension on the bottom in comparison to highs "the beaming" just because of the size of the transducer, the radiating area, not even taking account any electro-mechanical properties of real drivers! A compromise between two of our key simple requirements I already figured out and defined in the previous long post would give good loudspeaker performance as my goal. A trade-off between nice high SPL capability and nice dispersion through wide bandwidth!
--Beaming is pretty easy to experiment in VituixCAD diffraction tool, using ideal driver (of any size you input), to see the beaming depends on the transducer size in a way that when you increase the size of a transducer the beaming frequency goes down and if decrease the size the beaming frequency goes up. Put a 1" driver there and you'll see it starts to narrow its response below our target bandwidth! Put in a 15" driver and you see the dispersion starts to narrow roughly a bit below 1kHz, and for 8" similar thing happens roughly a bit above 1kHz line.
Lets think about a second what we need from those two ways, at minimum based on our few requirements. If we want very good performance of our nice high SPL capable wide bandwidth loudspeaker system to have good quality on the extremes of the bandwidth, the 2 ways we have has absolutely have to take account the maximum and minimum wavelengths on the bandwidth! That is where the bandwidth is defined and the quality is determined, in these two ways, at the two extremes! And their size needs to be such that both SPL and directivity requirements get fullfilled. As these two ways need to be optimized for the extremes of the bandwidth all compromises their design that have to do with the bandwidth need to be taken to ensure that it happens for the good of the extreme. This would leave the middle frequency range vulnerable for trade-offs since both of our ways take compromises!
Well, there is more to ways and bandwidths and compromises. Cut story short I have reasoned, from the wavelengths, that one should optimize any way (transducer and structure = construct) for its top end bandwidth performance since the wavelengths are shortest there and no other transducer can be added to aid with the performance. This implies that only way to better the performance is to change the construct! And conversely, due to lengthening wavelengths towards the lower end of any way bandwidth possibility to add more ways below without additional issues increases. Simplified, adding ways increases system bandwidth and SPL capability (and cost and size).
Anyway, compromises and trade-offs is the other realization I mentioned earlier that has given a lot to thinking speaker design, mind the trade-offs! And I've already written it to this thread and to many others. There is no way a goal can be met successfully if there is a compromise between two things you need to make it to the goal! We have to figure out a way to push trade-offs out from our goals way, out from the requirements, out from the needs, to areas that are less important or just outside of our goal scope. Using example above, I cannot use fullrange system because I want both SPL and nice dispersion from my system I'm designing. Hence going to have 2-way at least. And we can go to 3-ways or no-matter-how-many-ways if it is the way to make it to the goal we are designing for! Only if all trade-offs are out from audio to cost and size and looks and what ever we'd have best possible audio performance.
Here is few examples how to utilize thinking the trade-offs mentality in your project: I have the nice high SPL capability as one of the requirements in my system and I cannot trade that off to anything else! Except, the part that I don't need, the excess. Thinking this reversed, there is no need for stuff/capability that you don't need, since it could potentially prevent things happening that you need! Or another, you can factor in some extra into your design so that it can be thrown away at later stage as sacrifice instead of trade-off! For example if the system has a bit over SPL capability, it can usually be turned into extra low frequency extension with EQ to meet the bandwidth requirement!
Alright that is it for today.
Can you see your system developing already?! If you know what you are doing, what is the goal and what are the requirements, you'll know where you are at and what you need to be doing in order to get results.
I mean would you sacrifice your excess SPL capability to EQ if you don't know there is excess? Or are you trading-off your SPL to EQ without knowing it? Have you ever even thought about using EQ to your advantage? You might be using/thinking some set of drivers without knowing what is their capability in relation to expectation!
Human auditory perception is often mentioned to be about 20-20kHz so that would be the absolute maximum bandwidth we have to design a reproduction system for if seeking for good sound, a good speaker that doesn't take away. As mentioned earlier there is possibility to reduce the bandwidth requirements some depending on application and the listeners ability to perceive, and what the usual source material contains. But lets stick to the 20-20kHz for now.
Calculator gives wavelength for 20Hz roughly 17m and for 20kHz it is 1.7cm. 2kHz would be roughly 17cm and 200Hz in turn about 170cm. Now lets think about how the sizes relate to our daily lives. Starting from top of our target bandwidth the 20kHz is about the size of your belly button, 2kHz almost fits on palm of hand, 200Hz is a bit too big to hold on your lap comfortably and 20Hz needs a tennis court to fit, badminton court is not long enough, cheez!
Reasoning from this, even if we relaxed the extremes of our bandwidth requirement a bit, the wavelengts are so different in size at the extremes that covering that kind of a bandwidth would need at least 2-way system. I'm thinking of the nice high SPL requirement we have and directivity graphs found in the studies and mentioned earlier, that have been shown to give good listening impressions on blind listening tests, nice constant or at least smooth controlled directivity. We must need at least two transducers, big and small, since while one real world driver could do the whole bandwidth in paper the SPL capability of such system would be limited by the fact that low frequency SPL would benefit bigger cone area which in turn lowers frequency where high frequency beaming starts. It is a balancing act on any sized driver to have extension on the bottom in comparison to highs "the beaming" just because of the size of the transducer, the radiating area, not even taking account any electro-mechanical properties of real drivers! A compromise between two of our key simple requirements I already figured out and defined in the previous long post would give good loudspeaker performance as my goal. A trade-off between nice high SPL capability and nice dispersion through wide bandwidth!
--Beaming is pretty easy to experiment in VituixCAD diffraction tool, using ideal driver (of any size you input), to see the beaming depends on the transducer size in a way that when you increase the size of a transducer the beaming frequency goes down and if decrease the size the beaming frequency goes up. Put a 1" driver there and you'll see it starts to narrow its response below our target bandwidth! Put in a 15" driver and you see the dispersion starts to narrow roughly a bit below 1kHz, and for 8" similar thing happens roughly a bit above 1kHz line.
Lets think about a second what we need from those two ways, at minimum based on our few requirements. If we want very good performance of our nice high SPL capable wide bandwidth loudspeaker system to have good quality on the extremes of the bandwidth, the 2 ways we have has absolutely have to take account the maximum and minimum wavelengths on the bandwidth! That is where the bandwidth is defined and the quality is determined, in these two ways, at the two extremes! And their size needs to be such that both SPL and directivity requirements get fullfilled. As these two ways need to be optimized for the extremes of the bandwidth all compromises their design that have to do with the bandwidth need to be taken to ensure that it happens for the good of the extreme. This would leave the middle frequency range vulnerable for trade-offs since both of our ways take compromises!
Well, there is more to ways and bandwidths and compromises. Cut story short I have reasoned, from the wavelengths, that one should optimize any way (transducer and structure = construct) for its top end bandwidth performance since the wavelengths are shortest there and no other transducer can be added to aid with the performance. This implies that only way to better the performance is to change the construct! And conversely, due to lengthening wavelengths towards the lower end of any way bandwidth possibility to add more ways below without additional issues increases. Simplified, adding ways increases system bandwidth and SPL capability (and cost and size).
Anyway, compromises and trade-offs is the other realization I mentioned earlier that has given a lot to thinking speaker design, mind the trade-offs! And I've already written it to this thread and to many others. There is no way a goal can be met successfully if there is a compromise between two things you need to make it to the goal! We have to figure out a way to push trade-offs out from our goals way, out from the requirements, out from the needs, to areas that are less important or just outside of our goal scope. Using example above, I cannot use fullrange system because I want both SPL and nice dispersion from my system I'm designing. Hence going to have 2-way at least. And we can go to 3-ways or no-matter-how-many-ways if it is the way to make it to the goal we are designing for! Only if all trade-offs are out from audio to cost and size and looks and what ever we'd have best possible audio performance.
Here is few examples how to utilize thinking the trade-offs mentality in your project: I have the nice high SPL capability as one of the requirements in my system and I cannot trade that off to anything else! Except, the part that I don't need, the excess. Thinking this reversed, there is no need for stuff/capability that you don't need, since it could potentially prevent things happening that you need! Or another, you can factor in some extra into your design so that it can be thrown away at later stage as sacrifice instead of trade-off! For example if the system has a bit over SPL capability, it can usually be turned into extra low frequency extension with EQ to meet the bandwidth requirement!
Alright that is it for today.
Can you see your system developing already?!
If you know what you are doing, what is the goal and what are the requirements, you'll know where you are at and what you need to be doing in order to get results. I mean would you sacrifice your excess SPL capability to EQ if you don't know there is excess? Or are you trading-off your SPL to EQ without knowing it? Have you ever even thought about using EQ to your advantage? You might be using/thinking some set of drivers without knowing what is their capability in relation to expectation!
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Edit time over. I want to say that please question the text I wrote since there is quite some generalization in it. Mostly due to complexity of stuff and trying to compact it to some manageable size blob without good language skills and time.
After all my motivation is to make you the reader think about stuff, reasoning, dig into details when there is need to, do fact checking, experiments, question the old habits and other peoples writings and sayings, jadajada. You can do it!
Consider this: I know only one thing in common between any-way systems, ribbons, papyrus cones, snake oil, rooms, living rooms, ear canalshapes, musical taste and rocket launch all crammed into concept of loudspeaker design is the fricken wavelenghts in the room, the stuff you listen to So, maybe in the next post or maybe even this one we are at point where anyone can start imagining their actual needs and goals and requirements and shaking the marketing foo from the specifications by thinking wavelengths? Unless the goal is something else than trying to get good audio quality avoiding marketing foo It has been very abstract until now though, maybe a more practical context for next post?
After all my motivation is to make you the reader think about stuff, reasoning, dig into details when there is need to, do fact checking, experiments, question the old habits and other peoples writings and sayings, jadajada. You can do it!
Consider this: I know only one thing in common between any-way systems, ribbons, papyrus cones, snake oil, rooms, living rooms, ear canalshapes, musical taste and rocket launch all crammed into concept of loudspeaker design is the fricken wavelenghts in the room, the stuff you listen to
So, maybe in the next post or maybe even this one we are at point where anyone can start imagining their actual needs and goals and requirements and shaking the marketing foo from the specifications by thinking wavelengths? Unless the goal is something else than trying to get good audio quality avoiding marketing foo It has been very abstract until now though, maybe a more practical context for next post?
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Tmuikku - Wow - I can't keep up with your writing... So Many Words !!
Please do not take this the wrong way, and I say this with admiration for Finland and it's culture... I have colleagues and friends in the Finnish aviation industry that I have known for 25 years... and they have said fewer words to me over that 25 years than you have written here in the last couple of weeks !
Please do not take this the wrong way, and I say this with admiration for Finland and it's culture... I have colleagues and friends in the Finnish aviation industry that I have known for 25 years... and they have said fewer words to me over that 25 years than you have written here in the last couple of weeks !
It is a puke I know said some time ago it is going to be a communication exercice and I've been taking it forum format is all that I have written in English, and it is difficult, I'm not much of a writer in any language. My latest long posts in the thread are way out from forum format, but I think very relevant to the thread and recent discussion so I have let it flow when there has been some time.
I don't personally read most the long posts of others unless looking for info so am not offended if no-one reads mine. Writing helps with thinking, and most of the time I'm writing while thinking Heavy editing until the post is locked of course
said some time ago it is going to be a communication exercice and I've been taking it forum format is all that I have written in English, and it is difficult, I'm not much of a writer in any language. My latest long posts in the thread are way out from forum format, but I think very relevant to the thread and recent discussion so I have let it flow when there has been some time. I don't personally read most the long posts of others unless looking for info so am not offended if no-one reads mine. Writing helps with thinking, and most of the time I'm writing while thinking
Heavy editing until the post is locked of course
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Thanks for reading it Guerilla! It is a lot of effort
Yeah, hopefully the thread and message encourages people to start their own projects and topics for their applications! I think so too that this thread is dead, at least as long as people think and lush about brands and makes and models. There is not going to be a common project since every one wants different things just because of wanting them affected by what ever foo. The people who think what they need instead could meet common ground and perhaps make a group project eventually (or multiple for various applications). There is at least two of us who have thought and expressed close wall position in living room would be nice application. There must be plethora others who would benefit from it as well but never gave a thought on it.
Yeah, hopefully the thread and message encourages people to start their own projects and topics for their applications! I think so too that this thread is dead, at least as long as people think and lush about brands and makes and models. There is not going to be a common project since every one wants different things just because of wanting them affected by what ever foo. The people who think what they need instead could meet common ground and perhaps make a group project eventually (or multiple for various applications). There is at least two of us who have thought and expressed close wall position in living room would be nice application. There must be plethora others who would benefit from it as well but never gave a thought on it.
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Thanks Tmuikku for all the information and things to think. You put a lot of effort and time in it. Much appreciated.
I can follow in some way what you try to say. But I can not make decissions you are looking for because I don't know them. I don't have experience. I don't know what is the consequence for trading off SPL apart from turning the volume knob a bit higher.
You made a comparison between a car and a hifi system. I can follow that. Maybe I need a salon car and not a race car. But if I experienced a race car I can get some benefit from it. Maybe I realise that good strong breaks have their benefit. Maybe a strong engine give me that change to take over faster.
The thing is I can not make the trade offs. I can go and listen to many systems to get some understanding. Like going to some car dealers and try different cars, till I understand what is important for me.
But comparing speakers is different. If other drivers are used, other room etc will have impact on the sound.
If I can lets say a narrow 3-way tower speaker with high order XO and listen to it in my room I get a feeling of what it can bring. If I keep everything the same an only change the XO to lower order XO I can then evaluate what the impact is.
Same with time alignment, same with closed box, vented, TL, low diffraction baffle, etc..
You can only change 1 thing at a time to know what is the impact.
If I then get the full understanding of all this, then I can answer the questions to offer in a correct manner. but now....I simply don''t know.
And I do understand that you can not make all kinds of designs with 1 set of drivers...but I do think when choosing wisely you can do at least a few...
I can follow in some way what you try to say. But I can not make decissions you are looking for because I don't know them. I don't have experience. I don't know what is the consequence for trading off SPL apart from turning the volume knob a bit higher.
You made a comparison between a car and a hifi system. I can follow that. Maybe I need a salon car and not a race car. But if I experienced a race car I can get some benefit from it. Maybe I realise that good strong breaks have their benefit. Maybe a strong engine give me that change to take over faster.
The thing is I can not make the trade offs. I can go and listen to many systems to get some understanding. Like going to some car dealers and try different cars, till I understand what is important for me.
But comparing speakers is different. If other drivers are used, other room etc will have impact on the sound.
If I can lets say a narrow 3-way tower speaker with high order XO and listen to it in my room I get a feeling of what it can bring. If I keep everything the same an only change the XO to lower order XO I can then evaluate what the impact is.
Same with time alignment, same with closed box, vented, TL, low diffraction baffle, etc..
You can only change 1 thing at a time to know what is the impact.
If I then get the full understanding of all this, then I can answer the questions to offer in a correct manner. but now....I simply don''t know.
And I do understand that you can not make all kinds of designs with 1 set of drivers...but I do think when choosing wisely you can do at least a few...
Jeah it all feels disconneted until you have some experience. But there is much we can reason before building anything. The info is on the forums and publications, it is just hard to digest since it is mostly scattered around. There must be good books on loudspeaker design you could try and read. At leas at the level you currently understand, skip stuff that doesn't make sense or are too hard for now. Some day things will start to connect in your brain and you can then go deeper into details.
Here is another how to think the bass. The lowest bass frequencies are so long that they don't fit in the room! So, there is nothing that you can fit inside the room that has more effect on them than the room because the room is closer to the wavelengths and has higher chance to has some effect! Simplified, yes. Hence, the room will dominate the very low frequencies and how they behave inside the room, at the listening spot you are listening.
If your speaker doesn't output anything at 30Hz there won't be dip or peak at that frequency in the listening spot. But, if your speaker outputs -20db (anecoic) down at 30Hz from that what it outputs at 1kHz, there is high chance the room either adds the missing 20db to it or further subtracts 20db from it, at the listening position! In this case, you can think there is no difference if the anechoic box calculator produced graph output at 30Hz is -3 or -6 or -10db down if your room boosts it so much you have to EQ it down, or if there is a dip you are not going to hear any of the differences between the alignments, except from the harmonics they produce and what not!
Thinking like this, there really is no matter what alignment you use with your low bass box, the room controls the sound at listening position anyway. Change listening spot one meter left and the response can be completely different again. You have to take control over the room to really make difference here at the low bass, and dr. Geddes multi sub system seems one very sensible way to tackle it and there might be others like dipole or cardioid solutions but I haven't reasoned that way yet.
However, there is difference between the bass box alignment for other aspects in the system! Like cost and size, build difficulty. The drivers are suitable for one or another and may work suboptimal in wrong alignment. Then again, you might have deliberately limited the bandwidth in order to get more SPL with bandbass design, because you plan to add more subs later on to cover the missing bottom octave! Or, you have designed a reflex box to get to the 30Hz but didn't consider the mids leaking through the port at same level as the 30Hz, there is port and cabinet resonance that ruins the speaker. You could size and tweak a bass reflex system so that none of the resonances are a problem! You just have to work out the details and get a balance that is right for your system.
Imagine choosing between sealed and reflex alignment for example: you can pretty easily change from one to another just by blocking the port(s). You can plan the box so that port(s) open the extension is extends very low in frequency but maximum SPL capability is not very high because of high excursion. When you need low extension and low SPL is fine, a late night movie moment for example, you open up the port(s). But with the party you might wanna close the port(s) to limit bandwidth, thus woofer excursion, and get more SPL for the remaining bandwidth, the kick bass! But, now the speaker is sealed and heat builds up inside and the SPL gets down in turn due to the electro-mechanical stuff..
Well, if you don't know any of this it might be hard to figure out the trade-offs but believe me you can imagine some, usually at least one is pretty easy. Think these three things, what happens to the system: quality, cost, size. Getting even one trade-off down will give you better chance to get the compromises right in your system. If you wanna make a cheap system just go sealed. Reflex is not that much costlier but it takes some more time to tweak the problems out (mid leakage). In this light the sealed is fine, I even didn't think about audio quality aspect because I felt the cost is the important factor here. If you have planned a bass reflex box but don't know what the trade-offs are, try and google what people complain about bass reflexes and why is that, does it affect your particular build. Does it mean increased cost over sealed? Increased size? Decreased audio quality?
A bass reflex is sensible alignment for the lowest bandwidth way in your system because it extends the low bandwidth / SPL at the response knee (alignment). But again, this might not be good thing if your room has big boost there as well, there is no need for bass reflex in this case. For this reason I think sealed is fine, with some excess SPL capability baked in so that you have possibility to use room EQ and extra amplifier power to perhaps smooth out the response a bit. Basically you can just use any alignment you want, in which case I'd go for smallest size and cost and ease of build. A bass reflex whose port(s) can be blocked. More subs can be added.
The bottom line:
If you don't know what to do or think just question stuff you currently think. Question between why bass reflex instead of sealed, or would sealed be better? Google it up if you don't already know some trade-offs for both, and then decide which one would be better for your system in your application. If you just can't get to it just build something and get forward, you'll find out later if the system needs something else instead.
Here is another how to think the bass. The lowest bass frequencies are so long that they don't fit in the room! So, there is nothing that you can fit inside the room that has more effect on them than the room because the room is closer to the wavelengths and has higher chance to has some effect!
Simplified, yes. Hence, the room will dominate the very low frequencies and how they behave inside the room, at the listening spot you are listening. If your speaker doesn't output anything at 30Hz there won't be dip or peak at that frequency in the listening spot. But, if your speaker outputs -20db (anecoic) down at 30Hz from that what it outputs at 1kHz, there is high chance the room either adds the missing 20db to it or further subtracts 20db from it, at the listening position! In this case, you can think there is no difference if the anechoic box calculator produced graph output at 30Hz is -3 or -6 or -10db down if your room boosts it so much you have to EQ it down, or if there is a dip you are not going to hear any of the differences between the alignments, except from the harmonics they produce and what not!
Thinking like this, there really is no matter what alignment you use with your low bass box, the room controls the sound at listening position anyway. Change listening spot one meter left and the response can be completely different again. You have to take control over the room to really make difference here at the low bass, and dr. Geddes multi sub system seems one very sensible way to tackle it and there might be others like dipole or cardioid solutions but I haven't reasoned that way yet.
However, there is difference between the bass box alignment for other aspects in the system! Like cost and size, build difficulty. The drivers are suitable for one or another and may work suboptimal in wrong alignment. Then again, you might have deliberately limited the bandwidth in order to get more SPL with bandbass design, because you plan to add more subs later on to cover the missing bottom octave! Or, you have designed a reflex box to get to the 30Hz but didn't consider the mids leaking through the port at same level as the 30Hz, there is port and cabinet resonance that ruins the speaker. You could size and tweak a bass reflex system so that none of the resonances are a problem! You just have to work out the details and get a balance that is right for your system.
Imagine choosing between sealed and reflex alignment for example: you can pretty easily change from one to another just by blocking the port(s). You can plan the box so that port(s) open the extension is extends very low in frequency but maximum SPL capability is not very high because of high excursion. When you need low extension and low SPL is fine, a late night movie moment for example, you open up the port(s). But with the party you might wanna close the port(s) to limit bandwidth, thus woofer excursion, and get more SPL for the remaining bandwidth, the kick bass! But, now the speaker is sealed and heat builds up inside and the SPL gets down in turn due to the electro-mechanical stuff..
Well, if you don't know any of this it might be hard to figure out the trade-offs but believe me you can imagine some, usually at least one is pretty easy. Think these three things, what happens to the system: quality, cost, size. Getting even one trade-off down will give you better chance to get the compromises right in your system. If you wanna make a cheap system just go sealed. Reflex is not that much costlier but it takes some more time to tweak the problems out (mid leakage). In this light the sealed is fine, I even didn't think about audio quality aspect because I felt the cost is the important factor here. If you have planned a bass reflex box but don't know what the trade-offs are, try and google what people complain about bass reflexes and why is that, does it affect your particular build. Does it mean increased cost over sealed? Increased size? Decreased audio quality?
A bass reflex is sensible alignment for the lowest bandwidth way in your system because it extends the low bandwidth / SPL at the response knee (alignment). But again, this might not be good thing if your room has big boost there as well, there is no need for bass reflex in this case. For this reason I think sealed is fine, with some excess SPL capability baked in so that you have possibility to use room EQ and extra amplifier power to perhaps smooth out the response a bit. Basically you can just use any alignment you want, in which case I'd go for smallest size and cost and ease of build. A bass reflex whose port(s) can be blocked. More subs can be added.
The bottom line:
If you don't know what to do or think just question stuff you currently think. Question between why bass reflex instead of sealed, or would sealed be better? Google it up if you don't already know some trade-offs for both, and then decide which one would be better for your system in your application. If you just can't get to it just build something and get forward, you'll find out later if the system needs something else instead.
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I would say it is not very interesting to think about the product ("car"), as it limits you to the conditions of industry, who wants to sell products.
I would rather think about the journey or the process. Why not take the train or walk? You may find a better option than just buying a car. Diy is always a process. That's the intersting part of it.
Exactly, concentrating and restricting oneself to details and conventions prevents one to see all the options.
But there are too many options!! Yes, but you have to look each of them only so deep you can make educated decision which one should suit better and allow yourself to change mind later on when more details reveal. This is the message what I've been trying to deliver.
Wavelengths, the actual sound, is about the simplest perspective to look into all the available options at surface level, without having to get deep into details.
But there are too many options!! Yes, but you have to look each of them only so deep you can make educated decision which one should suit better and allow yourself to change mind later on when more details reveal. This is the message what I've been trying to deliver.
Wavelengths, the actual sound, is about the simplest perspective to look into all the available options at surface level, without having to get deep into details.
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A high quality on-wall design is likely to be a pretty good subject for a group project if the project is managed well. The reason being there are pretty much no DIY designs of this type and the demand for them is significant. One or two shallow and wide DIY designs but I am aware of only commercial ones using the passbands of the drivers which is likely to be the higher quality approach.
Handling the presence of the wall accurately in the simulations will require doing things in a slightly more general manner than usual. Possibly some prep required here which could help provide some focus for the project and avoid large amounts of waffle which has degraded this thread by not respecting the design outlined by the OP.
I am interested in building such a speaker for my own use and have already started outlining a design and considering which of my existing parts could be pressed into use for a first prototype. Unfortunately this strong interest is countered by the fact I am unlikely to make a particularly good group member when it comes to group decisions about design choices.
This discussion should not be taking place in the OPs thread about an 8" woofer, 4" midrange, 3 way using widely available budget drivers. If several people are interested it should be in it's own thread.
When you come to the point where you stop feeling disconnected and everything falls into place?
I started my DIY journey 1,5y ago. Studied and read a lot. I know about baffle step compensation, phase, driver integration, diffraction, group delay, bass reflex, etc. Played with Xsim and boxSim.
But at that point knowing it is not enough to start my own build and decided to make a proven design.
Now I want to go the next step.
How can I do that?
I read a lot..some technical concepts BSC, Diffraction are easy and quiet strqight forward to understand. You dont get much discusion about these subjects. But it is different when you start talking about high and lower XO. time-alignment, .... Some are convinced you have to go one way. Other are convinced to go the other way and you have the 3th group who decide case by case.
Just to say, there probably is some trued in all of them, hence I want to have first hand experience.
So how to go the next level now? I have a backpack with information. How can I use it now to make my own project?
To make it more practical :
I want to make a design, wide baffle (40cm) ala Troels PMS with SBacoustic drivers.
SB26ADC, SB15MFC-8 and SB23MFCL45-8 comes to mind.
crossover low point aming for 300 Hz. Why 11600/40 = 300. Thats where baffle step comes in and should be addressed only to the woofer.
Woofer sensitivity is only 85db while mid is 87db.
Is it a good choice for woofer?
SB23NBACS45-8 has 87,5db sensitivity? Better choise? But cabinet volume (40x12X100 with big curve) is around 20-25L. So I think this woofer isn't suited.
Next XO. mid and tweeter dont have baffle step so I assume the provided infinity baffle response can be used to simulate.
I play around with this mid and tweeter. Copy some designs and fiddle with the values, but I dont come to a good XO design.
Hence how do you approach this? what is a good startpoint. How you look at breakup...harmonic distortion....
many many questions but no answers in my head
I'm noticing this more and more. People know stuff before they actually build. They get build anxiety.
In this internet age it looks like information is around and needs to be absorbed before starting. Don't be fooled, it's not that different. Build something before you know so much that the fear of making a mistake stops you.
You don't know what it sounds like if you don't....
In this internet age it looks like information is around and needs to be absorbed before starting. Don't be fooled, it's not that different. Build something before you know so much that the fear of making a mistake stops you.
You don't know what it sounds like if you don't....
As an exception to the above, these are not easy. People usually don't have much to say about them because most of the descriptions have been boiled down to simple concepts. You won't begin to know these until you get to the point where you focus on them in your builds.
Absolutely! take the first builds as prototypes, no need for finishing. Just test the performance, get measurements, try and make xo, check if resonances, build difficulties, anything. Make new prototype with problems fixed. Prototyping will inevitably lead to a better outcome!
I'm still with mono prorotype after few years of slow development, enjoying music from the day 5 or so when got first system up Been tweaking various aspects, learning building techniques, simulation, listening xo and what not. Problem has beem lack of time, been renovating the house with all the spare time and money. Maybe next year will finally make a stereo system
I'm still with mono prorotype after few years of slow development, enjoying music from the day 5 or so when got first system up
Been tweaking various aspects, learning building techniques, simulation, listening xo and what not. Problem has beem lack of time, been renovating the house with all the spare time and money. Maybe next year will finally make a stereo system Well we are all in different situations. I made a proven design. Made a soundbar with the left over wood.
If I start a new build it needs to be a "short pain" and successful build. ( I need to do woodwork in the bathroom...you know how much dust MDF makes. I spent more time cleaning then building.
So short and successful build is a must.
Otherwise I can fill in the divorce papers. So good preparation is needed
If I start a new build it needs to be a "short pain" and successful build. ( I need to do woodwork in the bathroom...you know how much dust MDF makes. I spent more time cleaning then building.
So short and successful build is a must.
Otherwise I can fill in the divorce papers. So good preparation is needed
You can obviously increase cabinet volume, see link below with a Troels PMS like speaker using a CA26RFX. Reading the build process is also interresting IMHO. Maybe I'll buid something like that one dayMrHifiTunes said:To make it more practical :
I want to make a design, wide baffle (40cm) ala Troels PMS with SBacoustic drivers.
SB26ADC, SB15MFC-8 and SB23MFCL45-8 comes to mind.
crossover low point aming for 300 Hz. Why 11600/40 = 300. Thats where baffle step comes in and should be addressed only to the woofer.
Woofer sensitivity is only 85db while mid is 87db.
Is it a good choice for woofer?
SB23NBACS45-8 has 87,5db sensitivity? Better choise? But cabinet volume (40x12X100 with big curve) is around 20-25L. So I think this woofer isn't suited.
Seas 3-way wide baffle
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I already have a set of 23NRX per side playing here, but will continue to wonder if 23NBAC, WO24, Dayton RS225 or something else, would do a better job - for me. Because how can I read something on the internet and convince myself that someone else's mind is better at figuring out what I like to hear? Objective evidence might be the key, but maybe I just have to buy the WO24, play with them and convince myself that I can make an objective decision, that they play better than the much cheaper 23NRX, that I already have.
My little private brainstorm, to figure out to come further towards my personal reference system
My little private brainstorm, to figure out to come further towards my personal reference system
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