Different bass drivers measure differently. Different Vas, Qt, Fs. Box size is determined by those, the desired type of bass response (boomy, deep and accurate, missing) and price. Manufacturers pick a target audience, design a device to appeal to them, and try to succeed. Different goals include flat frequency response, response emphasizing a particular frequency, wide dispersion or narrow dispersion, short distance to listener (monitor) or long (Public Address) , speaker location on front of stage or against wall in a room, speaker installation on floor or above an audience to prevent blockage of highs, low distortion or distortion that pleases a certain customer, visual cues and tricks.
The mathematics can be reviewed in various articles and sources. I purchased David Weems Designing Building and Testing Your Own Speaker used for $11. There are other books and some online sources. Read other threads on this forum for zero cost education.
The mathematics can be reviewed in various articles and sources. I purchased David Weems Designing Building and Testing Your Own Speaker used for $11. There are other books and some online sources. Read other threads on this forum for zero cost education.
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If you want to design your own speaker and be assured that you will not miss anything the first time, then unreasonable expectations will lead to painful experiences. Designing your own speaker is better done for the journey and the friends we make along the way. How well it turns out depends on how many times you are able to change your mind, improve your knowledge and viewpoint before you lose interest.
If you build a speaker vetted by the DIY community you are more likely to end up with something that both you and others will like in the end without all the unexpected twists and turns of a full blown career-hobby.
The way to settle on a direction without continual second-guessing is to get to know local audiophiles and DIYers and audition as many systems as you can gain access to. Youtube reviews and sound recordings can show some things but they can be misleading and nothing comes near the confidence of being there and hearing a real one.
The least investment for a good speaker would probably be to construct a DIY project that comes with a flatpack so you can fit the box together like LEGO. Unless you are already handy with a tablesaw and router, the hypothetical cost savings of cutting your own box pale in comparison to the effort/tools required, although new skills could extend to other areas of your life in unexpected but welcome ways.
Thanks ! I’m trying some of the online box calculators and they are giving me the volume but not the dimensions.
Square dimension boxes are supposed to be the worst in theory, yet i see all these subwoofer enclosures which are roughly square
Boxes with a dimension ratio of 0.6:1:1.6 are better
Seems to be something to do with standing waves, minimizing something about the air pressure bouncing around inside the enclosure. What should I use on the internal walls of the speaker enclosure to address that. I can staple some of that white wadding stuff on, or is there anything better
Square dimension boxes are supposed to be the worst in theory, yet i see all these subwoofer enclosures which are roughly square
Boxes with a dimension ratio of 0.6:1:1.6 are better
Seems to be something to do with standing waves, minimizing something about the air pressure bouncing around inside the enclosure. What should I use on the internal walls of the speaker enclosure to address that. I can staple some of that white wadding stuff on, or is there anything better
Speakers are an expression/manifestation of what the designer thinks is important for a given application. Think of them like food and think of designers like chefs and you'll not be far wrong. Alternatively, the "tool for a job" analog has appeal, and you can think of those like vehicles--cars are not trucks, etc.
https://www.diyaudio.com/community/...n-your-own-speaker-from-scratch.332688/latest
https://www.diyaudio.com/community/...n-your-own-speaker-from-scratch.332688/latest
The wavelength of sub frequencies, <120 hz, is so long internal reflections do not matter. Wavelengh 10 m or 30' or larger. The box is tiny compared to that.
Internal reflections happen at frequency L/speed of sound . There are various threads about substances to put on walls to limit reflections. Check out the "steel wool for box stuffing" thread to see various options. I like the magic eraser option. Steel wool is not recommended due to metal shards in the driver gap.
An interesting woofer, at a sensible second hand price, if you can afford that.
Probably not the most sensible choice for a first design, but with help from the community it could be made to work, but at the same time I think it would need a robust and therefore a more expensive tweeter to make a two way design.
Expect to be possibly below 2KHz for a suitable Xover and the resonance peak of the bass cone at 7-8KHz will need some extra care and more Xover components to notch it out.
Just out of interest, your first post mentioned both Seas and Visaton drivers you aren't thinking of their full range devices are you ? Maybe have a quick look in the full range forum to see if there is anything of interest there.
You now have a candidate woofer in a 28Litre box, you now need to pick a tweeter that can be used down low or a full range unit crossed in the 300-800Hz region. Possibly a FAST design like that would help suppress the woofer breakup peak enough for it to not be a concern. However a low Xover point will definitely need larger inductor and capacitor for the woofer. Have a read here:
It would be sensible to let us understand your room size, desired listening levels, near field, far field listening, preferred music types and amplifier power.
Probably not the most sensible choice for a first design, but with help from the community it could be made to work, but at the same time I think it would need a robust and therefore a more expensive tweeter to make a two way design.
Expect to be possibly below 2KHz for a suitable Xover and the resonance peak of the bass cone at 7-8KHz will need some extra care and more Xover components to notch it out.
Just out of interest, your first post mentioned both Seas and Visaton drivers you aren't thinking of their full range devices are you ? Maybe have a quick look in the full range forum to see if there is anything of interest there.
You now have a candidate woofer in a 28Litre box, you now need to pick a tweeter that can be used down low or a full range unit crossed in the 300-800Hz region. Possibly a FAST design like that would help suppress the woofer breakup peak enough for it to not be a concern. However a low Xover point will definitely need larger inductor and capacitor for the woofer. Have a read here:
Some sound clips of this speaker recorded with my phone and powered by my SuSyLu 100w Class A amp:
Test of SuSyLu 100W Class A Amp - YouTube
Example of speaker in dark “espresso brown” stain and satin lacquer with Duratex coated baffle.
Example of beautiful build by as8912:
Another Example of a...
Test of SuSyLu 100W Class A Amp - YouTube
Example of speaker in dark “espresso brown” stain and satin lacquer with Duratex coated baffle.
Example of beautiful build by as8912:
Another Example of a...
It would be sensible to let us understand your room size, desired listening levels, near field, far field listening, preferred music types and amplifier power.
For the record, the geometrical Xmax of the Scan is bigger than that of the FaitalPro, 5,8mm to 4,2mm. And I doubt thermal compression will be an important issue in a 2-way fullrange design.
Thanks ! I am thinking the same as you, that under 2khz would be a good crossover frequency in a 3 way system. Looking at the frequency response graph the sound may start to break up at 2khz and above
Online crossover calculators are suggesting 1.2mh inductor and a 10uf capacitor for a second order 12db/octave attenuation rate, to give a crossover frequency of 1.5khz
Online crossover calculators are suggesting 1.2mh inductor and a 10uf capacitor for a second order 12db/octave attenuation rate, to give a crossover frequency of 1.5khz
Never trust those online calculators, they don't work on measurements of the driver in the box. And that is needed for accurate crossovers. Not a generic calculation on a fixed impendance plot that does not represent the driver at all. The filter reacts on the impendance of the driver, that varies depending on the frequency and the load of the amplifier
Maybe you could take some time with Vituixcad to model the woofer behaviour when mounted to you baffle and then look at the modelled frequency response to see what Xover values will be eventually required.
I haven't used it but I think you can also model baffle responses in a piece of software called Basta.
The trouble with online calculators they do not account for the response of a driver when mounted in an enclosure due to the baffle step/ diffraction loss, you will probably need differing components once this is factored in.
As others have said maybe a proven kit might help you get this right the first time, especially if you cannot measure your design. It can be done, but these things can take some time. Have a look at the Seas Aphel design there is quite a bit of information there and maybe the beginnings of a possible candidate for a suitable tweeter with a Xover design included. you would need to keep baffle within those dimension to keep the response shape.
I haven't used it but I think you can also model baffle responses in a piece of software called Basta.
The trouble with online calculators they do not account for the response of a driver when mounted in an enclosure due to the baffle step/ diffraction loss, you will probably need differing components once this is factored in.
As others have said maybe a proven kit might help you get this right the first time, especially if you cannot measure your design. It can be done, but these things can take some time. Have a look at the Seas Aphel design there is quite a bit of information there and maybe the beginnings of a possible candidate for a suitable tweeter with a Xover design included. you would need to keep baffle within those dimension to keep the response shape.
Shapes and sizes are often based on popular trends. Skinny and tall has been in vogue for some time, often with numerous drivers arranged vertically. (Just check out a number of commercial sites to see that trend). In the seventies, the classic bookshelf speaker was the style. It takes guts to swim against the current and produce something 'different'. That, in part, is the joy of DIY, you're not trying to please a market and, hopefully, turn a profit but rather make something you find aesthetically pleasing and which sounds good to you. And if the first try doesn't achieve those aspirations, build another one.
This is true. For a first design, however, the best approach would be to stay with conventional, well proven concepts. For example, a 2-way speaker with a 6" midbass driver and a tweeter, in a conventional box (either sealed or vented), is complicated enough that it will be a challenge for a new designer... but it is not so complicated that it is unachievable. Copying a successful formula is a path to success for new designers.
A successful "outside the box" design, one which goes in a new direction with new innovation, is something that normally can only come from a very experienced mind. It would be a very rare genius who could design such a thing on their first attempt.
Manufacturors make things that will sell, not necesairly what is best. For some sound quality is an argument, but for a lot it's not, it's what gives the most profit in their target market. And a lot of commercial speakers are not that good at all. You can today find many measured by people like Amir (AudioScienceReview) or Erin (Erin's Audio Corner) and others. And very often you're surprised with the results, and not in a good way.
This is something i have a lot of arguements over. From the science subjects i studied the only thing that can stop sound is a vacuum. Everything else has vibratable molecules in it that help to move the sound.The sound from the speaker is vibrating the air and using the air as the conducting medium to get the music to you. When someone is playing music in the room next door you can hear it because the sound is shaking the bricks and mortar of the wall and using that as the conducing medium. That's why only a vacuum can stop sound because there is nothing to shake.
That's why i find it difficult to believe when people say the speaker enclosure traps the rear radiation, the wood the cabinet is made of contains vibratable elements so the rear radiation will use that as the vibratable medium and just pass straight through. Where does this leave the theory of standing waves, or trapping the sound within the speaker box - proven science says it is not possible
I like it but i find 2-way speakers boring. I've tried building speakers using a single drive unit and i don't believe one drive unit can handle the full " bandwidth " of sounds the human ear can hear very effectively. I tried 2-way and that was better, but 3-way where the bass midrange and treble has its own dedicated drive unit sound the best, higher highs and deepers lows, more detail
It’s not only about sound transmission. While of some importance, it’s not the biggest issue in enclosures. In fact for transmission alone any decent sheet material would do a reasonable job.
The issue however is resonances. Panel resonances and resonances of the air in the enclosure. Or port resonances. And their interaction. So it’s merely a time domain thing. The original sound gets contaminated with ringing enclosure panels, with panels, cones or other radiating elements driven by standing waves (resonances) inside the box. Adding unwanted sound.
Thanks! What makes you think the visaton's are poor drive units, is there anything that stands out, any specs, any information. They are german made drive units and have a good following in germany - had to use google translate. Not much elsewhere in the world.
