Domed midranges are made that way to produce a wider dispersion pattern. This is more effective at higher frequencies, which is why you often see dome tweeters. Using a domed midrange is an attempt to more closely match the dispersion patterns of the tweeter down into the midrange band.
On the large midrange woofer the center plastic plug. Is a a phase plug. There used to help extend the frequency range of the driver higher. . And yes you are correct the shape the cone does make a difference. It's just not everyone can hear the difference (not all ears are the same ) I don't know much about building speakers but I do like to play with them and learn. And I do listen and test several pair a year
Dome midrange has worse dispersion than a cone midrange where it meets the tweeter. Seems it would be the opposite, but its not, has to do with the coil coupling. Yes that pushed in dustcap will make a response difference at the top end of the woofer. Yes the bullet in the center of the woofer is used to disperse the top end resopnse and its called a phase plug. Put an 8 ohm resistor across that tweeter terminals and it will make you much happier.
It will be interesting to see the final mods and how they sound. Typically anytime you change a driver the crossover must be changed to accommodate that it. Changing 2 of the 3 drivers is gonna be interesting for sure. I love mods and can’t wait to see the results.
Get the most out of your low-end driver you may want to check the box tuning with the new woofer. This could easily be done with the impedance analyzer on your Discovery Pro. With the woofer installed the Box all sealed up, run an impedance sweep on the low end adjust the port length until you get to even impedance humps below 200 HZ. Hopefully the speaker that you bought doesn't have Qts that is too high for ported design.
The horn tweeter being recessed could add a time delay in relation to the midrange and cause a bit of a top end dip. Might be worthwhile also testing them wired in reverse phase to the midrange.
I don't see the horn loaded tweeter in the ScanSpeak lineup but I did see the straight soft dome. It's listed at 91.5 dB/M/W sensitive and a 4.5 ohm impedance so it would probably match the mid driver better. It would still have to be padded down about 5-6 dB to be linear.
Hi Steph 👋 I’d check some of Janos’ vids on Real World Audio. He’s an audio guru of sorts, and knows DIY speakers, amps, etc. He’s built pretty much his ENTIRE system, cuz no one made gear he was satisfied with, and I think that’s why a lot of us get into DIY. I think the L-pad is a great idea. A friend of mine named Mariusz Stark added a tweeter and an L-pad to the rear of a pair of bookshelf speakers. Even over UA-cam, you can hear the difference it made in the instrument separation and low end. I’ll email you a couple links. Congrats on being so close to 10K subs! You deserve every single one of em. I think people are drawn to you due to your no nonsense way of doing things, your obvious passion for DIY HiFi, detailed explanations of your builds, etc. etc. You’re great, Stephe, and people definitely realize that. 🔊😊🎶💜
On the woofers, really won't make a difference if they are crossed over below a certain frequency. Main reason for a dome in the centre is better off axis response beyond a certain point. In a three way I see no issues.
IME the usual reason for a prominent dust cap like the original speaker is to stiffen the diaphragm near the centre and limit mechanical resonances. On some it will contain some damping material (BAF wadding, usually) to absorb air movement noise too (I have a pair where the designer removed stock Vifa dustcaps and fitted hard plastic pointy ones filled with BAF, for just this reason). The larger coils on the yellow jobs probably just don't need it. The different shapes will have very little effect on dispersion or anything else. With a large motor the diaphragm is more evenly supported and can be nearer a flat piston shape. Personally, 2 out of 3 of my 'wow' speakers (speakers I heard that forever changed my mind about what was possible) had midrange domes. The first was the Celestion Ditton 66, the second a ProAc studio with the big, fat, hideously expensive ATC mid. I'm not much a fan of ribbon tweeters, Though they can sound fabulous they have directivity problems as you observe, with a very small 'sweet spot'.
Started assembling my 2.2-a and had trouble getting the cross-overs to work. I think the inductors were not getting into the circuit. Pulled them out and tinned the leads and reinstalled and think they are working now. Surprised how much they attenuated the high frequencies, but will not be confident they are working till I hear them. Below 100hz full signal goes thru has pole and 1.5khz, on tweeter only about 20% of the signal voltage hits the tweeter. Not sure what is normal to see on cross overs, maybe I messed up by measuring without a load connected.
if you can find the color you want in rustoleum professional, that dries a lot quicker. Has more solvent in it or something, and it has that fake banana smell like old spray paint had.
Domes make sense at high frequencies... The 'plastic protusion is a kinda 'phase plug' so the midrange coming from that driver is a bit more coherent IIRC Subs arent nearly as critical - as long as theres no holes in the cone or coil scrapes !!
LOl sure aint - them big Yellow jobbies aint gonna see 1000hz er, are they?? Oh hold on if youre replacing the black number WITH them, I guess they ARE!? the yellow ones look more like their meant for woofer service @@SkunkieDesignsElectronics
My criticism of this kit is that it should have come with terminal clips for the speaker terminals. After three revisions of the crossover now, I am sick and tired of desoldering and resoldering terminals every time I make a change. My advice to a new builder would be to use terminal clips first. Once you perfect your crossover, you can cut the clips and solder the wires for permanent speaker connections !
I don't think you will notice any audible difference between the concave/convex woofers. At lower frequencies, dispersion becomes wider and more omni-directional, even wrapping around the cabinet at frequencies that have wavelengths longer than the width of the baffle. The dust cap difference will probably only be noticeable in the REW measurements at higher frequencies, where woofers naturally have narrowing dispersion...commonly called, "beaming". Generally, crossovers are designed to roll off the woofer's response to the midrange driver before beaming becomes too noticeable. Which is why i don't think you'll hear any difference between the two woofers. As mention in the last video, you can try to gently pull out the damaged dustcap with a vacuum if it bothers you.
That "dust cap" is part of the cone itself, is not a separate thing and is pretty stiff. There is no "gently" moving it, I tried the vacuum trick and it didn't begin to move. In theory I agree, but I have also learned to question theoretical conclusions and empirically test. Especially when what is being called a "dust cap" is 30%+ of the surface area of the moving cone. I think the driver is still going to be doing stuff at 1K so this shape could impact the sound. We will test and see!
@@SkunkieDesignsElectronics It'll be interesting to see/hear what happens. It's too bad the vacuum trick didn't work. Now we know why there was such a discount on them!
It shouldn't and also shouldn't impact the crossover point. It goes in after the crossover and just shifts some of the speaker load to a resistive load.
Domed midranges are made that way to produce a wider dispersion pattern. This is more effective at higher frequencies, which is why you often see dome tweeters. Using a domed midrange is an attempt to more closely match the dispersion patterns of the tweeter down into the midrange band.
The colour looks great. Looking forward to your testing.
Yeah I think it's gonna look great when it's all assembled.
On the large midrange woofer the center plastic plug. Is a a phase plug. There used to help extend the frequency range of the driver higher. . And yes you are correct the shape the cone does make a difference. It's just not everyone can hear the difference (not all ears are the same ) I don't know much about building speakers but I do like to play with them and learn. And I do listen and test several pair a year
FYI, the solid projection from the driver is called a phase plug. I understand it helps with lobeing and sound cone shaping.
Dome midrange has worse dispersion than a cone midrange where it meets the tweeter. Seems it would be the opposite, but its not, has to do with the coil coupling. Yes that pushed in dustcap will make a response difference at the top end of the woofer. Yes the bullet in the center of the woofer is used to disperse the top end resopnse and its called a phase plug. Put an 8 ohm resistor across that tweeter terminals and it will make you much happier.
It will be interesting to see the final mods and how they sound. Typically anytime you change a driver the crossover must be changed to accommodate that it. Changing 2 of the 3 drivers is gonna be interesting for sure. I love mods and can’t wait to see the results.
My goal is to bring everyone along in my learning process. I do plan to swap just the woofers first, test, and then play with changing the tweeter.
I can't wait to see how that L-Pad install works out. I'm thinking of trying that on my GR Research Minis.
I think I will likely do it as a temp install and then once I figure out what sounds and measures well, I can hardwire this correction.
Get the most out of your low-end driver you may want to check the box tuning with the new woofer. This could easily be done with the impedance analyzer on your Discovery Pro. With the woofer installed the Box all sealed up, run an impedance sweep on the low end adjust the port length until you get to even impedance humps below 200 HZ. Hopefully the speaker that you bought doesn't have Qts that is too high for ported design.
The horn tweeter being recessed could add a time delay in relation to the midrange and cause a bit of a top end dip. Might be worthwhile also testing them wired in reverse phase to the midrange.
Good idea!
I don't see the horn loaded tweeter in the ScanSpeak lineup but I did see the straight soft dome. It's listed at 91.5 dB/M/W sensitive and a 4.5 ohm impedance so it would probably match the mid driver better. It would still have to be padded down about 5-6 dB to be linear.
If you are going to do tweeter attenuator, try a stepped attenuator type deal. Maybe a three or four way switch
Hi Steph 👋 I’d check some of Janos’ vids on Real World Audio. He’s an audio guru of sorts, and knows DIY speakers, amps, etc. He’s built pretty much his ENTIRE system, cuz no one made gear he was satisfied with, and I think that’s why a lot of us get into DIY.
I think the L-pad is a great idea. A friend of mine named Mariusz Stark added a tweeter and an L-pad to the rear of a pair of bookshelf speakers. Even over UA-cam, you can hear the difference it made in the instrument separation and low end. I’ll email you a couple links.
Congrats on being so close to 10K subs! You deserve every single one of em. I think people are drawn to you due to your no nonsense way of doing things, your obvious passion for DIY HiFi, detailed explanations of your builds, etc. etc. You’re great, Stephe, and people definitely realize that. 🔊😊🎶💜
Thanks!!
Fun stuff. Probably could use a longer port.
On the woofers, really won't make a difference if they are crossed over below a certain frequency. Main reason for a dome in the centre is better off axis response beyond a certain point. In a three way I see no issues.
We will see shortly :)
IME the usual reason for a prominent dust cap like the original speaker is to stiffen the diaphragm near the centre and limit mechanical resonances. On some it will contain some damping material (BAF wadding, usually) to absorb air movement noise too (I have a pair where the designer removed stock Vifa dustcaps and fitted hard plastic pointy ones filled with BAF, for just this reason). The larger coils on the yellow jobs probably just don't need it. The different shapes will have very little effect on dispersion or anything else. With a large motor the diaphragm is more evenly supported and can be nearer a flat piston shape.
Personally, 2 out of 3 of my 'wow' speakers (speakers I heard that forever changed my mind about what was possible) had midrange domes. The first was the Celestion Ditton 66, the second a ProAc studio with the big, fat, hideously expensive ATC mid.
I'm not much a fan of ribbon tweeters, Though they can sound fabulous they have directivity problems as you observe, with a very small 'sweet spot'.
Started assembling my 2.2-a and had trouble getting the cross-overs to work. I think the inductors were not getting into the circuit. Pulled them out and tinned the leads and reinstalled and think they are working now. Surprised how much they attenuated the high frequencies, but will not be confident they are working till I hear them. Below 100hz full signal goes thru has pole and 1.5khz, on tweeter only about 20% of the signal voltage hits the tweeter. Not sure what is normal to see on cross overs, maybe I messed up by measuring without a load connected.
Have you listened to them?
That's normal, higher frequencies use a lot less power at tweeter level, so that way of measuring is null and void.
Its a phase plug on the bass driver for phase
I'm intrigued to see how it goes. I'm thinking your regular viewers will start to question whether they want to bother with this model at all. 😅
Depends on how it turns out :P If you want a build it and forget it, get the 2.2a.
Sometimes you can pop the dent out of the dome with some tape
I succeeded in doing that with a collapsed tweeter dome (oops!).
if you can find the color you want in rustoleum professional, that dries a lot quicker. Has more solvent in it or something, and it has that fake banana smell like old spray paint had.
Thanks for the tip!
Domes make sense at high frequencies... The 'plastic protusion is a kinda 'phase plug' so the midrange coming from that driver is a bit more coherent IIRC
Subs arent nearly as critical - as long as theres no holes in the cone or coil scrapes !!
Is 1000hz "sub"?
Yes, you may want to save that speaker for a two-way design you don't need it Optimum mid-range from it on a three-way
LOl sure aint - them big Yellow jobbies aint gonna see 1000hz er, are they??
Oh hold on if youre replacing the black number WITH them, I guess they ARE!?
the yellow ones look more like their meant for woofer service
@@SkunkieDesignsElectronics
My criticism of this kit is that it should have come with terminal clips for the speaker terminals. After three revisions of the crossover now, I am sick and tired of desoldering and resoldering terminals every time I make a change. My advice to a new builder would be to use terminal clips first. Once you perfect your crossover, you can cut the clips and solder the wires for permanent speaker connections !
I don't think you will notice any audible difference between the concave/convex woofers. At lower frequencies, dispersion becomes wider and more omni-directional, even wrapping around the cabinet at frequencies that have wavelengths longer than the width of the baffle. The dust cap difference will probably only be noticeable in the REW measurements at higher frequencies, where woofers naturally have narrowing dispersion...commonly called, "beaming". Generally, crossovers are designed to roll off the woofer's response to the midrange driver before beaming becomes too noticeable. Which is why i don't think you'll hear any difference between the two woofers. As mention in the last video, you can try to gently pull out the damaged dustcap with a vacuum if it bothers you.
That "dust cap" is part of the cone itself, is not a separate thing and is pretty stiff. There is no "gently" moving it, I tried the vacuum trick and it didn't begin to move.
In theory I agree, but I have also learned to question theoretical conclusions and empirically test. Especially when what is being called a "dust cap" is 30%+ of the surface area of the moving cone. I think the driver is still going to be doing stuff at 1K so this shape could impact the sound. We will test and see!
@@SkunkieDesignsElectronics It'll be interesting to see/hear what happens. It's too bad the vacuum trick didn't work. Now we know why there was such a discount on them!
Right! lol I've been playing with REW today and have a really good video planned.
What became the end result on your Modded Swan 3.1A's ? Is a update video regarding these in the works or did I miss it ? Hope it worked out for ya !
Got side tracked, I have an idea or two I still want to try.
now I am questioning getting these, almost done with the build. If the bass is that bad/lacking
I'd love to hear your impression.
Does having an L-pad have any impact on phase?
It shouldn't and also shouldn't impact the crossover point. It goes in after the crossover and just shifts some of the speaker load to a resistive load.
Use a vacuum cleaner to suck the dust cover (yellow) out.