Well I've finished reading "Suitable midrange cone, for bandpass mid in Unity horn"; what an epic. Unfortunately in more recent years it goes off topic more frequently and contains a fair bit that should really have been in other/new threads so it takes progressively longer to get through, but there are still some useful nuggets of info in later pages. This time I took bookmarks, so hopefully won't need to go through it all a third time, anyway. Though there are so many even of those that they will now take me some time to sort out and assimilate.
Time is one of the wider messages that come through; the thread spans 16years as people work on and gain knowledge with multiple entry horns. It has taken some a long time to make theirs, and often they go on to make more refined/improved versions too, before they're content with the results. Not just the physical horn, but taking (audio) measurements and sorting out the DSP can take months and much learning.
It probably will be similar for me; I'm getting a handle on the physical layout of the horns and I've used many basic PC-based active crossovers before, but for this project theres a whole field of software involving terms like IIR, FIR, PEQ etc that I shall probably want to learn about. Reading some threads, I may even have to learn about MS Windows (once it is finally installed) to stop it secretly dicking around with test signals and recordings.
TBH I had been frustrated with laptop issues delaying me, but now I can better put that into perspective. I'm seeing this as a journey to relax into and enjoy, rather than expecting a finished product any time soon. So even if I end up with a design similar to others, it won't simply be a quick copy but something I have hopefully understood, and juggled to meet my own requirements. I'm quite looking forward to it, I was getting a bit bored with building direct radiators so this might renew my interest in speakers. I'm increasingly keen on the concept, the more I read about unitys and synergies.
Time is one of the wider messages that come through; the thread spans 16years as people work on and gain knowledge with multiple entry horns. It has taken some a long time to make theirs, and often they go on to make more refined/improved versions too, before they're content with the results. Not just the physical horn, but taking (audio) measurements and sorting out the DSP can take months and much learning.
It probably will be similar for me; I'm getting a handle on the physical layout of the horns and I've used many basic PC-based active crossovers before, but for this project theres a whole field of software involving terms like IIR, FIR, PEQ etc that I shall probably want to learn about. Reading some threads, I may even have to learn about MS Windows (once it is finally installed) to stop it secretly dicking around with test signals and recordings.
TBH I had been frustrated with laptop issues delaying me, but now I can better put that into perspective. I'm seeing this as a journey to relax into and enjoy, rather than expecting a finished product any time soon. So even if I end up with a design similar to others, it won't simply be a quick copy but something I have hopefully understood, and juggled to meet my own requirements. I'm quite looking forward to it, I was getting a bit bored with building direct radiators so this might renew my interest in speakers. I'm increasingly keen on the concept, the more I read about unitys and synergies.
I'm trying to decide if 2x cheap faitalpro 4FE35 will be "enough" for me, or whether I should either step up to 4x or move on to 2x B&C 4NDF34. On paper, I believe a 1.7" (44mm) diaphragm compression driver should safely reach about 102db at xmax before any horn gain. But even a single 4fe35 will reach that, so in theory two should be more than fine for keeping up, assuming similar horn/waveguide gain.
The mids are not operating as normal; they're in a band-pass situation, so should get some gain there too. However in my ignorance, I don't know precisely what this implies for driver selection, but e.g. some have suggested that BL and robust cones are important - not just for SPL but also for things like low distortion and longevity. The faitals are similar sensitivity but have less than half the BL of the B&Cs, about 1/3rd the power handling, and softer weaker looking rubber surrounds. The qes & fs formula can be broken so this may not matter, but FWIW it also gives an impressive result for the B&Cs, whilst the faitals score very low by comparrison.
I know that a few people have tried the faitals or similar, and in fact Mark100 moved up from them to the B&Cs, no doubt for good reason. So I'd be keen to hear opinions on this choice. I have some of the faitals so would only need a few more (and they're much cheaper here anyway). But this project is likely to span many months and a number of iterations so if the B&Cs were a substancially better or safer bet then I'd work a few more days of overtime to get them.
Thanks,
Kev
The mids are not operating as normal; they're in a band-pass situation, so should get some gain there too. However in my ignorance, I don't know precisely what this implies for driver selection, but e.g. some have suggested that BL and robust cones are important - not just for SPL but also for things like low distortion and longevity. The faitals are similar sensitivity but have less than half the BL of the B&Cs, about 1/3rd the power handling, and softer weaker looking rubber surrounds. The qes & fs formula can be broken so this may not matter, but FWIW it also gives an impressive result for the B&Cs, whilst the faitals score very low by comparrison.
I know that a few people have tried the faitals or similar, and in fact Mark100 moved up from them to the B&Cs, no doubt for good reason. So I'd be keen to hear opinions on this choice. I have some of the faitals so would only need a few more (and they're much cheaper here anyway). But this project is likely to span many months and a number of iterations so if the B&Cs were a substancially better or safer bet then I'd work a few more days of overtime to get them.
Thanks,
Kev
Hi Kev, my vote is to start with the 4fe35's you already have.
They worked totally fine in my first syn9 prototype, which was my first attempt at adding small mids.
On second syn9, I went with the 4NDF34's mainly because I was hoping to build a 'killer' final build, imagining better mids would help.
The second version didn't sound as good as the first haha. I attributed the downtick to a narrower 75x50 pattern, than the proto's 90x60.
And then built third try, another 90x60 and am happy with it....it's my current speaker in LCR., that i ended up calling syn10.
I do not know if it would matter to syn10, whether it uses the B&C or the Faitals...i really doubt it would.
Oh, Nice thing is, the screw mounting holes are the same for both drivers, so substitution is easy-peasy if you later decide to give a try / move up, to the B&C
They worked totally fine in my first syn9 prototype, which was my first attempt at adding small mids.
On second syn9, I went with the 4NDF34's mainly because I was hoping to build a 'killer' final build, imagining better mids would help.
The second version didn't sound as good as the first haha. I attributed the downtick to a narrower 75x50 pattern, than the proto's 90x60.
And then built third try, another 90x60 and am happy with it....it's my current speaker in LCR., that i ended up calling syn10.
I do not know if it would matter to syn10, whether it uses the B&C or the Faitals...i really doubt it would.
Oh, Nice thing is, the screw mounting holes are the same for both drivers, so substitution is easy-peasy if you later decide to give a try / move up, to the B&C
Thanks! That is really helpful, it doesn't sound like I could go far wrong either way then, but if their mounting holes are the same then even better. I could probably even make the frustrum (and any back chamber) customisable, in case I ever felt the need to upgrade as you did. I'm happy with that; I quite like the little faitals so may never want to upgrade.
Thanks again!
Kev
Thanks again!
Kev
I got a couple more 4fe35 drivers, so now i have four (two per speaker). Even found some lighty used on ebay, which seem to be in great condition, so the cost thus far has been tiny.
I gave up on resurrecting the windows laptop; so for now I set up a basic virtual machine instead. Installed hornresp... and soon realised learning this will not be a particularly quick process. The potential is very evident, it is superb that David has created and offered this to us (thank you!!!), and i found the meh wizard. But I don't (yet) know what aspects many of the parameter codes/labels refer to, or even what their expected units are, so i can't usefully enter much data at this stage. Clearly, it'll be some time before I get any results that I might begin to trust.
Which is fine, I will get there. But if anyone knows of a good MEH or even general guide to using hornresp, especially one with diagrams of how the parameter codes relate to geometry, I'd be keen to hear.
Cheers,
Kev
I gave up on resurrecting the windows laptop; so for now I set up a basic virtual machine instead. Installed hornresp... and soon realised learning this will not be a particularly quick process. The potential is very evident, it is superb that David has created and offered this to us (thank you!!!), and i found the meh wizard. But I don't (yet) know what aspects many of the parameter codes/labels refer to, or even what their expected units are, so i can't usefully enter much data at this stage. Clearly, it'll be some time before I get any results that I might begin to trust.
Which is fine, I will get there. But if anyone knows of a good MEH or even general guide to using hornresp, especially one with diagrams of how the parameter codes relate to geometry, I'd be keen to hear.
Cheers,
Kev
Hornresp Help by Karlsson as a general guide is helpful:
https://www.diyaudio.com/community/threads/hornresp-manual.383370/
https://www.diyaudio.com/community/threads/hornresp-manual.383370/
Thank you, Art, that looks very useful! A slight shame (for me) that he stops short of giving a worked MEH example, but the parameters etc are all there and the tapped horn in particular seems to have a lot in common.
I spent a few hours yesterday tinkering with hornresp. It is starting to feel more familiar now, and I'm beginning to understand more of its own help menu too. I did manage to create a 3-way MEH, though I've no idea if it was reliable. Seems unlikely to have been, given the complexity for a first attempt, and certainly the bass drivers (which shouldn't get much horn loading) simulated quite differently in an equivalent WinISD bandpass box. Though WinISD isn't exactly bug-free, which is a secondary reason for my interest in hornresp.
Unfortunately I then managed to delete the records instead of closing them. That doesn't matter (and I know what I did wrong), but it shows that I've got some way still to go!
I spent a few hours yesterday tinkering with hornresp. It is starting to feel more familiar now, and I'm beginning to understand more of its own help menu too. I did manage to create a 3-way MEH, though I've no idea if it was reliable. Seems unlikely to have been, given the complexity for a first attempt, and certainly the bass drivers (which shouldn't get much horn loading) simulated quite differently in an equivalent WinISD bandpass box. Though WinISD isn't exactly bug-free, which is a secondary reason for my interest in hornresp.
Unfortunately I then managed to delete the records instead of closing them. That doesn't matter (and I know what I did wrong), but it shows that I've got some way still to go!
I've made some more hornresp progress, achieving a crude 3-way MEH design. Very basic at this stage; I've not even touched the HF driver or horn throat contours. Really just looking at what output I can get from drivers and their chambers before Xmax. But I'm not confident, as there is so much to get wrong; I was even confusing which fields wanted litres and which ones wanted cc, at one point.
If anyone has a moment, I would appreciate a brief second opinion on the attached records to see if I'm even vaguely getting this simulation right (I've not yet even considered subtleties like tap/aperture shapes etc). I'm particularly keen to know if ME2 (with the Fane 8-225) looks sensible, since I may buy these drivers based on my dodgy sim!
Thanks very much,
Kev
If anyone has a moment, I would appreciate a brief second opinion on the attached records to see if I'm even vaguely getting this simulation right (I've not yet even considered subtleties like tap/aperture shapes etc). I'm particularly keen to know if ME2 (with the Fane 8-225) looks sensible, since I may buy these drivers based on my dodgy sim!
Thanks very much,
Kev
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So this is roughly the size of waveguide that I'm envisaging before extensions or flares are added. In practice it'll be rectangular and 90 by 60 degrees, around 50cm wide and 30cm tall. Though with the bass drivers top and bottom the overall size of the speaker itself will be about 50cm tall as well. Thats a bit bigger than originally intended but having worked on the implications of being smaller, my intentions have changed a bit!
This is the maximum output I'm apparently able to expect from the Fane Sovereign 8-255 and the Faital Pro 4FE35. If my crude sims are to be trusted, and before any EQ or further port/chamber/horn tweaking is done to flatten the initial raw response. First the fane 8" for bass, would be used up to say 300hz-400hz depending on how I tweak things:
I can't see myself ever needing more than 100dB peaks per driver, so once EQ'd it 'seems' I could hope for them being flat down to 30hz. Which I'm somewhat suspicious of being true, since that is much lower frequency than I expected from only an 8" with 62hz Fs in a 4th order box. I was intending to use subwoofers up to at least 60Hz; I probably still would, but it would be very nice to have the option of these being full range if/when wished.
Then the FaitalPro 4FE35 for midrange (something like 300hz-400hz up to 1khz)
Though whilst the 8" Fane is at Xmax in its passband:
The 4FE35 only reaches Xmax a couple/few hundred hertz below its lower cross-over; in reality that will be attenuated and it could then go much louder. So whilst I had doubts about using only two of these drivers per speaker, they seem to be more than enough. In fact one would be enough, though I'll still use two in order to achieve symmetrical taps/apertures:
(All the above is for just one of each driver; in practice there would be two of each on the waveguide.)
So I remain suspicious of having cocked up my first hornresp sims somewhere. But if this is vaguely correct then I shall have output to spare. I could consider smaller bass drivers to make an even smaller waveguide, however the bass-driver's tap position means I wouldn't save very much on the footprint, just a small amount of height.
This is the maximum output I'm apparently able to expect from the Fane Sovereign 8-255 and the Faital Pro 4FE35. If my crude sims are to be trusted, and before any EQ or further port/chamber/horn tweaking is done to flatten the initial raw response. First the fane 8" for bass, would be used up to say 300hz-400hz depending on how I tweak things:
I can't see myself ever needing more than 100dB peaks per driver, so once EQ'd it 'seems' I could hope for them being flat down to 30hz. Which I'm somewhat suspicious of being true, since that is much lower frequency than I expected from only an 8" with 62hz Fs in a 4th order box. I was intending to use subwoofers up to at least 60Hz; I probably still would, but it would be very nice to have the option of these being full range if/when wished.
Then the FaitalPro 4FE35 for midrange (something like 300hz-400hz up to 1khz)
Though whilst the 8" Fane is at Xmax in its passband:
The 4FE35 only reaches Xmax a couple/few hundred hertz below its lower cross-over; in reality that will be attenuated and it could then go much louder. So whilst I had doubts about using only two of these drivers per speaker, they seem to be more than enough. In fact one would be enough, though I'll still use two in order to achieve symmetrical taps/apertures:
(All the above is for just one of each driver; in practice there would be two of each on the waveguide.)
So I remain suspicious of having cocked up my first hornresp sims somewhere. But if this is vaguely correct then I shall have output to spare. I could consider smaller bass drivers to make an even smaller waveguide, however the bass-driver's tap position means I wouldn't save very much on the footprint, just a small amount of height.
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Hi Kev,
A few things I've used for my models that may help (I hope they are correct things to do, I'm self taught with speaker building so may be doing something wrong without realising
)
Check the particle velocity at the throat exit port at xmax to see if it is ok. I try and keep below 17ms which may scupper your 30Hz plans. You need a lot of air moving through the port for 30Hz. I tried a pair of lab12 drivers with sealed backs on one test box and EQ'd them for 35Hz. You could easily hear the distortion on kick drum transients when driven at 'decent' levels. (~150W) I use the 17ms figure as that is what I use for normal BP boxes. Apparently the frustums lower velocity a bit like port flares do. (Think that's mentioned in the patent)
Model the entrance ports as frustums if you intend to use them. My mid ports were 0.4cm long in my model.
If you are doing a rectangular horn, use the BWaslo XL spreadsheet to generate your figures to input into Hornresp, this will give you your secondary flare figures aswell. (I use Libre Office for the spreadsheet, )
Export your Hornresp responses into REW to have a play with in the EQ section, it's really useful for XO work.
Regards,
Rob.
A few things I've used for my models that may help (I hope they are correct things to do, I'm self taught with speaker building so may be doing something wrong without realising
)Check the particle velocity at the throat exit port at xmax to see if it is ok. I try and keep below 17ms which may scupper your 30Hz plans. You need a lot of air moving through the port for 30Hz. I tried a pair of lab12 drivers with sealed backs on one test box and EQ'd them for 35Hz. You could easily hear the distortion on kick drum transients when driven at 'decent' levels. (~150W) I use the 17ms figure as that is what I use for normal BP boxes. Apparently the frustums lower velocity a bit like port flares do. (Think that's mentioned in the patent)
Model the entrance ports as frustums if you intend to use them. My mid ports were 0.4cm long in my model.
If you are doing a rectangular horn, use the BWaslo XL spreadsheet to generate your figures to input into Hornresp, this will give you your secondary flare figures aswell. (I use Libre Office for the spreadsheet, )
Export your Hornresp responses into REW to have a play with in the EQ section, it's really useful for XO work.
Regards,
Rob.
Thank you for the tips, Rob; very helpful. That looks like a nice path to take towards getting a good design. At the moment I've just started with rules of thumb for almost everything, to get a general idea and some practice with hornresp. That includes port size (IIRC I used 1/8th of driver Sd) and haven't yet reduced their length or introduced frustrum shapes, so hopefully there is a lot of improvement and refinements to be made before even a prototype is cobbled together. Though I may make a crude one just to see how reliable my simulations are.
The increased velocity at low frequencies is also a very good point, I shall have to check it out and see what is sensible. It seems likely that I will use subs when SPLs are normal or high - partly for port noise and partly for placement options - and perhaps only consider the MEHs full-range in small rooms and quiet situations.
I'll be using computer-based EQ so it should be possible to have different profiles for the driver roll-offs according to the application - e.g. quiet, normal and loud/party situations. But there is a long way to go before I reach that stage.
Thanks again,
Kev
EDIT: FWIW attached is a small schematic I made to work out roughly what was wanted before plugging the values into hornresp. There may well be errors in my understanding, and some things people disagree on too, so it'll be interesting to see what BWaslo's spreadsheet and Hornsrep think of my attempt.
The increased velocity at low frequencies is also a very good point, I shall have to check it out and see what is sensible. It seems likely that I will use subs when SPLs are normal or high - partly for port noise and partly for placement options - and perhaps only consider the MEHs full-range in small rooms and quiet situations.
I'll be using computer-based EQ so it should be possible to have different profiles for the driver roll-offs according to the application - e.g. quiet, normal and loud/party situations. But there is a long way to go before I reach that stage.
Thanks again,
Kev
EDIT: FWIW attached is a small schematic I made to work out roughly what was wanted before plugging the values into hornresp. There may well be errors in my understanding, and some things people disagree on too, so it'll be interesting to see what BWaslo's spreadsheet and Hornsrep think of my attempt.
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