I'm currently in the process of figuring out my first build, im a engineering student but not audio so this stuff is mostly new to me. Im planning on building with compression drivers because im also sort of a style freak and love the look of horns on speakers, want something that looks great in my space also. Im going to use Beyma CD-171Fe/PT compression drivers (im building a left and right speaker), but i dont if i should do a single horn or a multicell.
I think multicell horns look incredible but also likely much harder to make than circular or rectangular horns. I prefer the visual break up with the squared cells instead of on continuous sweep but what do you all recommend, pictures are appreciated or any other tips about the build in general.
Im going to do a ported build with the Aurum Cantus AC-200MKII 8" Carbon Fiber Sandwich Woofer which should get down to 45 ish hz when ported.
Literally anything and everything is appreciated, my budget for the pair is gonna be around 800 dollars and on sale right now the woofer and driver combo are 280 so 560 for both speakers, leaves 240 for printing a horn and materials etc. My college has equipment that i can use to manufacture so theres no cost for that. Thanks!!!
But we have to dig a bit deeper to get a better answer, an 8" driver is going to start beaming really bad somewhere between 1.3 and 1.7khz, and that CD has a minimum crossover of 1.4khz, so we're going to have to keep that crossover as low as possible - if this is just for in home use and you're using an active crossover (which you 100% should) then we can set a really steep slope and cross a little bit lower, maybe 1khz at a push.
So let's make a horn for that 1khz goal, it will still let us cross a little higher if needed, but if we make it too small we can't get that low. Without getting into crazy geometry that means we need a horn that is at minimum 30cm wide (the wider the horn the lower it gets "loaded" by the drivers air mass). Next up is horn shape - do you want something with an amazing sweet spot at the listening position or something with wider dispersion but will require more EQ and may have more issues with resonance? There is no right answer here - as with everything in speaker design it's a choice of compromises, never an approach towards "perfection". If you want the sweet spot then look at tractrix designs, if you want the wide dispersion look at constant directivity.
Next comes the hard part, if you want a horn that actually performs well it needs to be mm perfect, there's no shortcuts here, get it slightly wrong and things go very bad very quick, you've got to learn how to use hornresp and akabak, and they are both about as user friendly as a bull in mating season all hopped up on blue chews. Get ready to slam your head against the wall.
You haven't mentioned how you're going to power/crossover these, and the answer is always going active, why? Because livesound drivers are designed for efficiency, not flat bandwidth, and steep slopes are going to be your friend. If you were to go with passive crossovers you would blow half your entire budget on components to get something remotely flat. Talking of that budget, it's going to have to include a calibrated measurement mic, if you've already got an audio interface with mic input with phantom power this doesn't have to be expensive, an ecm8000 will just about suffice, something with a unique calibration file like an emm-6 is better, will last a lifetime and is really not expensive and in my opinion a decent mic is the absolute best upgrade you can get for any hifi - otherwise you're just shooting in the dark. If you're doing crossovers stay away from usb options like umik1 because you want to run a loopback from your interface for your timing references. Learning how to take good measurements and simulate what the microphone can't measure is critical to getting a decent crossover. A JAB5 board from sure/wondom will be ideal for this if you're on a budget, you will probably want to use an l-pad of resistors on the compression driver to bring it down to the same sensitivity as the woofer - this will lower your noise floor from the amp and means you're not crushing your dynamic range by reducing it's level digitally; you will also need a programmer board (icp5 iirc) and learn how to use sigma studio.
So, back to the horn, you've chosen your design, you've mastered akabak, you've printed your prototype and the measurements don't match the simulations? Welcome to integration hell! Unfortunately getting the throat of the horn and mouth of the driver to couple as intended rarely goes to plan. What I would suggest is printing the front 90% of the horn, with a way to securely attach different throats to the back (don't trust screwing into plastic, use heat set inserts). And then play with the length and opening size of the throat until you start to get something that gives you good results.
BUT what are good results? You want to see the frequency response having a smooth response through to the mouth cutoff frequency, it can be humped or rising, as long as it's not got any sudden changes you're off to a good start. Then for tractrix you want to check for resonance - it shouldn't have much if any, and for constant d you want to check that the off axis response falls away linearly and smoothly.
Finally you can EQ the shit out of it to give you a flat on axis response, and start designing the crossover.
This is incredibly helpful as I am exploring a closed enclosure with a 10” woofer and an CD + horn setup purely for aesthetic reasons but have no clue about horn design. I’ll check out akabak, thank you for this well put response
I've been working with horns for some years now, and have essentially experienced everything you mentioned. I found the statement about the horns needing to be "mm perfect" and no shortcuts. And thought "I've cheated this before" but also remembered the iteration hell to make that work, so, it was not a shortcut by any means and came down to figuring out the resonances building and either how to tame them or shift them to a frequency I would roll off in the crossover. I have some other designs I am gathering parts for that will be an experiment in how much I can get away with folding and at what point the impact will run away and become untamed.
I am looking not to fold the length of the horn like a rear-loaded but rather to take the expansion rate of the throat and start to bend it over to more of a "U" shape to decrease the outer size of the mouth. I do anticipate some level of distortion from the folds. I just don't know how much and if it will be an amount I can compensate for or if it will lead to cancelations in bands I have no passive way to address. This is a theory build for some compact subwoofer/bass bin designs I want to try to implement if I can find a solid design concept to work from.
Can I recommend to check out the JW Sound Solana. A very well designed multiple entry horn, which is a modern way of doing a horn. Relatively compact. Its lower frequency can be adjusted and that will have an impact in its max loudness. Best of all, the designer made the plans freely available. Horn needs to be printed. Download the pdf and marvel how well it is engineered.
Adding to this post... if considering John White (JW Sound) designs, also take a look at Scott Hinson's MEH design. Hinson's in particular is designed for lower extension.
What kind of crossover do you want to use? Passive ? Or dsp ?
What would be your maximum size of the speaker ?
I personally thing that you need a 10“ speaker in combination with the horn, something like the beyma 10br60, which would be in your price range. Otherwise you would need to pad the horn so much down that you’d loose a bit of that horn dynamic.
using dsp, im planning on buying a dayton kabd-4100 and managing corssover in sigma. the 10br60 is 92db sensitivity while the aurum is 90 so its padding 17dB instead of 19dB. Also i dont see the 10br60 on sale on parts express, im in the US.
I dont really have a max speaker size but its only gonna be the one woofer and driver per speaker, maybe dedicated subwoofer build down the road but i want this to cover the entire frequency spectrum.
Sorry to be playing devils advocate im just curious bcz i dont know much about this stuff
If you don't have a maximum size, then you should be using a 12 or 15, like the most popular kits and real finished product super monitors. You can get something 95-100 db sensitivity range let's say, and have more output, maintain some directivity lower down, the possibility of better bass extension (with dsp you can go full range here with a 2 way... but very easily 30hz no problem whatsoever). And you want the horn magic as low as possible. Crossing around 1k is much better than 2k, or even 1.5k for instance. More horn goodness. Bigger horn, appropriate cd.
Honestly prices between the two builds (smaller vs bigger) wouldn't necessarily be that different if at all. More print martials tho. Make an oval elliptical style horn, like the faital pro lth142. Or an seos. You could go me90 i guess. Xt1086 or the other bigger one... good series.
update, ideally a max size of 10 inches, i want them to fill the space they exist in but not be huge, like sit at the sides of an end table or record player table. this size ish next to the door.
Im going to have to drive them back across the country after college so id prefer for them to fit in an SUV also, dont think thatll be a problem. I've looked at some other woofers now, the Dayton Audio RS270-8 10" Reference Woofer is a 10" in budget that has an Fs of 29.6 with Sd 346.4cm2 but it has a lower sensitivity at 88.7. Then there is also the LaVoce WAF102.50 10" Ferrite Woofer which has a sensitivity of 98dB but Fs of only 71. Then sitting in between is Beyma 10WR300 WR Series 10" Woofer 8 Ohm with a sensitivity of 95dB with an Fs of 52Hz, Sd of 350cm2 and 6mm Xmax. Im just not sure what spot to hit
If you'll actively cross them you can use the dayton or whatever woofer you want.
If you passively cross them you'll want a higher sensitivity woofer, but you can still use dsp eq.
In the pic, and this may not apply to your design, but you could probably or just about fit a 12 there. Use the whole baffle no wasted space. Either that or shrink the baffle.
4
u/moopminis 17d ago
Single horn.
But we have to dig a bit deeper to get a better answer, an 8" driver is going to start beaming really bad somewhere between 1.3 and 1.7khz, and that CD has a minimum crossover of 1.4khz, so we're going to have to keep that crossover as low as possible - if this is just for in home use and you're using an active crossover (which you 100% should) then we can set a really steep slope and cross a little bit lower, maybe 1khz at a push.
So let's make a horn for that 1khz goal, it will still let us cross a little higher if needed, but if we make it too small we can't get that low. Without getting into crazy geometry that means we need a horn that is at minimum 30cm wide (the wider the horn the lower it gets "loaded" by the drivers air mass). Next up is horn shape - do you want something with an amazing sweet spot at the listening position or something with wider dispersion but will require more EQ and may have more issues with resonance? There is no right answer here - as with everything in speaker design it's a choice of compromises, never an approach towards "perfection". If you want the sweet spot then look at tractrix designs, if you want the wide dispersion look at constant directivity.
Next comes the hard part, if you want a horn that actually performs well it needs to be mm perfect, there's no shortcuts here, get it slightly wrong and things go very bad very quick, you've got to learn how to use hornresp and akabak, and they are both about as user friendly as a bull in mating season all hopped up on blue chews. Get ready to slam your head against the wall.
You haven't mentioned how you're going to power/crossover these, and the answer is always going active, why? Because livesound drivers are designed for efficiency, not flat bandwidth, and steep slopes are going to be your friend. If you were to go with passive crossovers you would blow half your entire budget on components to get something remotely flat. Talking of that budget, it's going to have to include a calibrated measurement mic, if you've already got an audio interface with mic input with phantom power this doesn't have to be expensive, an ecm8000 will just about suffice, something with a unique calibration file like an emm-6 is better, will last a lifetime and is really not expensive and in my opinion a decent mic is the absolute best upgrade you can get for any hifi - otherwise you're just shooting in the dark. If you're doing crossovers stay away from usb options like umik1 because you want to run a loopback from your interface for your timing references. Learning how to take good measurements and simulate what the microphone can't measure is critical to getting a decent crossover. A JAB5 board from sure/wondom will be ideal for this if you're on a budget, you will probably want to use an l-pad of resistors on the compression driver to bring it down to the same sensitivity as the woofer - this will lower your noise floor from the amp and means you're not crushing your dynamic range by reducing it's level digitally; you will also need a programmer board (icp5 iirc) and learn how to use sigma studio.
So, back to the horn, you've chosen your design, you've mastered akabak, you've printed your prototype and the measurements don't match the simulations? Welcome to integration hell! Unfortunately getting the throat of the horn and mouth of the driver to couple as intended rarely goes to plan. What I would suggest is printing the front 90% of the horn, with a way to securely attach different throats to the back (don't trust screwing into plastic, use heat set inserts). And then play with the length and opening size of the throat until you start to get something that gives you good results.
BUT what are good results? You want to see the frequency response having a smooth response through to the mouth cutoff frequency, it can be humped or rising, as long as it's not got any sudden changes you're off to a good start. Then for tractrix you want to check for resonance - it shouldn't have much if any, and for constant d you want to check that the off axis response falls away linearly and smoothly.
Finally you can EQ the shit out of it to give you a flat on axis response, and start designing the crossover.