Steve, Ani's build has a quad of 4 ohm woofers in the Isobaric arrangement. Thus is a pair of 2 ohm woofer systems when wired up. If Ani had 4x channels with 2x of those at 2 ohm stability, this could work. Since the woofer system should be run as a whole, it would take either a 1 ohm stability, or run the 2 ohm pairs in series for 4 ohms.
Yes, for the Indy theme, it's going to be pretty whacky and wonky... For long term, this will be a traditional 3 way with BSC, since I do not gain any sensitivity.
Hence I can cross the mid a bit high to minimise cone leackage and do not have to cross at 800hz range or whereever it fits best - option is to leave it 2.5 with the sealed chamber rolling off the mid if there is minimal improvement with 3 way.
I am really interested to see what the final distortion figures look like particulatly in the lower frequencies and if isobaric has any mesurable impact.
The MAC05 is well suited for 45Hz in about 0.5 cuft. Streching it lower was making the box very large. ISO barcicmade it possbiel to have 2x woofers in a 1 cu ft with a 10Hz lower extension. The MAC06 is a better woofer for going low in a smaller box, but I have a whole lot of 6.5" woofers sitting here and didn't want to take on another 6.5" woofer project.
Then there was the theme - so an opportunity to try something different for me, with still a path to make it usable, so that this beautiful cabinet and drivers are not wasted.
Once I have the cabinets and do some measurement, I'll start a new thread and we'll all dig into it...
I have my little 2 way ready for sanding and paint. I normally seal with shellac before I do any other finish work with MDF. Does anyone else have any suggestions I should try? These will get rattle can spray paint when I'm done. Thanks.
If I can sand without going through the shellac then I will often skip primer as the dewaxed shellac should be a great first layer (a lot of wood sealers have shellac). If I'm worried I went through or need to build up a few layers for more sanding I will get filler primer. If I have a screw up I'll get glazing putty.
MAC-4's are really nice and have about a 3" useful diameter cone - should be interesting as I replace the HiVi DMB-A's with them and then slip the NeoCd3.5H Horn in place of the HiVi RT1.3WE in there next . . .
Hoping they could be somewhat budget friendly distortion crushers. Sealed for use with sub to keep the MAC05s under control through the whole signal range. A reference 2-way of sorts for me.
Eventually.. when I get around to it. No more driver purchases for me (except maybe for experimentation) until I whittle down this backlog. Saying it out loud so hopefully it sinks in mah brain
Is that the (formerly) MCM tweeter? If so, it is extremely low distortion but does have some errata in top octave. Arguable if it matters that high or not.
Sb26cdc ceramic coated aluminum.
Though, not exactly the most inexpensive. It still seemed to have quite alot of bang for the buck. Potentially giving some exotics a run for their money, for a much less exotic price. I couldn't find much for complaints on the sound but we'll see.
Thanks to some quick CNC work by Ken Rhodes, these are starting to take shape and looking good. They'll be a 2.5-way with individual ported enclosures for each of the MAC-04s, for the simple reason that I wanted the chambers to be proportioned according to the golden ratio. 5"x8"x13" internal dimensions for each, which turns out to be a healthy (and almost exact) 0.30 cu ft gross volume. Ken made me some 3D printed flanged 2" ports as well, one for each chamber. Once I get them together, I'll start a new thread with some measurements and crossover stuff.
Attn. smart guys
A WTWW 2.5 way using 3 MAC06's all wired in parallel the bottom woofer will be for baffle step correction so it will have a series inductor perhaps .5 ohms DCR. What will be the Z min. I am thinking 3.3 Ohms, not sure. Any helpers out there?
7.8ohm/3=2.6ohm + whatever other series resistance. Probably an oversimplification though.
Technically I suppose it depends on box tune and where you tune the lowpass on the ".5".. The closer those ranges are, the less the impedance would dip between the woofer box tune peak and the low pass rise. So the net result is likely higher than the above "worst case" atleast somewhat.
I recall talking to someone at Iowa DIY while looking at the specs and saying that its more like a 9 or 10 Ohm driver. So I'm thinking the DCR might be a misprint.
@Eggguy said:
I recall talking to someone at Iowa DIY while looking at the specs and saying that its more like a 9 or 10 Ohm driver. So I'm thinking the DCR might be a misprint.
Not necessarily a misprint. A dcr of 7.8 is pretty high for an "8ohm" driver if you compare to others.
I'd think you would be able to pull off a safe enough impedance for a 4ohm stable amp once all the filters are in place. But then again that is me betting with your money
It is likely that over an ohm of series resistance will be implemented in such a design, provided you use air core coils.
I think you would be safe with three in parallel.
Comments
Steve, Ani's build has a quad of 4 ohm woofers in the Isobaric arrangement. Thus is a pair of 2 ohm woofer systems when wired up. If Ani had 4x channels with 2x of those at 2 ohm stability, this could work. Since the woofer system should be run as a whole, it would take either a 1 ohm stability, or run the 2 ohm pairs in series for 4 ohms.
InDIYana Event Website
Ooops I missed that detaial
Yes, for the Indy theme, it's going to be pretty whacky and wonky...
For long term, this will be a traditional 3 way with BSC, since I do not gain any sensitivity.
Hence I can cross the mid a bit high to minimise cone leackage and do not have to cross at 800hz range or whereever it fits best - option is to leave it 2.5 with the sealed chamber rolling off the mid if there is minimal improvement with 3 way.
I am really interested to see what the final distortion figures look like particulatly in the lower frequencies and if isobaric has any mesurable impact.
The MAC05 is well suited for 45Hz in about 0.5 cuft. Streching it lower was making the box very large. ISO barcicmade it possbiel to have 2x woofers in a 1 cu ft with a 10Hz lower extension. The MAC06 is a better woofer for going low in a smaller box, but I have a whole lot of 6.5" woofers sitting here and didn't want to take on another 6.5" woofer project.
Then there was the theme - so an opportunity to try something different for me, with still a path to make it usable, so that this beautiful cabinet and drivers are not wasted.
Once I have the cabinets and do some measurement, I'll start a new thread and we'll all dig into it...
Should be a great speaker. Is Brad going to finish (paint) them?
Brad is not finishing/painting them. I'll have some base coat on them and then try to finish them sometime in the summer If work isn't too crazy.
I have my little 2 way ready for sanding and paint. I normally seal with shellac before I do any other finish work with MDF. Does anyone else have any suggestions I should try? These will get rattle can spray paint when I'm done. Thanks.
Do you primer before paint?
If I can sand without going through the shellac then I will often skip primer as the dewaxed shellac should be a great first layer (a lot of wood sealers have shellac). If I'm worried I went through or need to build up a few layers for more sanding I will get filler primer. If I have a screw up I'll get glazing putty.
That was my first thought as well - pick up an inexpensive used pro audio amp and let 'er rip.
I am fairly certain my Dreadnaught would handle it - took about a minute to blow a 10A fuse at a dead short at an Iowa event lol.
If you can find it, the shellac based BIN primer is great. I do like the the 2K primer rolled on if you want to start down that path.
.
MAC-4's are really nice and have about a 3" useful diameter cone - should be interesting as I replace the HiVi DMB-A's with them and then slip the NeoCd3.5H Horn in place of the HiVi RT1.3WE in there next . . .
Eh?
Matchy matchy. Or if you prefer fancy words, homogeneous aesthetics with a symmetrical radiation pattern
Hoping they could be somewhat budget friendly distortion crushers. Sealed for use with sub to keep the MAC05s under control through the whole signal range. A reference 2-way of sorts for me.
Eventually.. when I get around to it. No more driver purchases for me (except maybe for experimentation) until I whittle down this backlog. Saying it out loud so hopefully it sinks in mah brain
Is that the (formerly) MCM tweeter? If so, it is extremely low distortion but does have some errata in top octave. Arguable if it matters that high or not.
Sb26cdc ceramic coated aluminum.
Though, not exactly the most inexpensive. It still seemed to have quite alot of bang for the buck. Potentially giving some exotics a run for their money, for a much less exotic price. I couldn't find much for complaints on the sound but we'll see.
That’s the Tweeter JimH had in Iowa 2023.
Thats a good tweeter - that enitre SB ceramic line is pretty good.
Yeah, you will definitely have a nice low-distortion banger there.
In rotation again.
Thanks to some quick CNC work by Ken Rhodes, these are starting to take shape and looking good. They'll be a 2.5-way with individual ported enclosures for each of the MAC-04s, for the simple reason that I wanted the chambers to be proportioned according to the golden ratio. 5"x8"x13" internal dimensions for each, which turns out to be a healthy (and almost exact) 0.30 cu ft gross volume. Ken made me some 3D printed flanged 2" ports as well, one for each chamber. Once I get them together, I'll start a new thread with some measurements and crossover stuff.
Attn. smart guys
A WTWW 2.5 way using 3 MAC06's all wired in parallel the bottom woofer will be for baffle step correction so it will have a series inductor perhaps .5 ohms DCR. What will be the Z min. I am thinking 3.3 Ohms, not sure. Any helpers out there?
7.8ohm/3=2.6ohm + whatever other series resistance. Probably an oversimplification though.
Technically I suppose it depends on box tune and where you tune the lowpass on the ".5".. The closer those ranges are, the less the impedance would dip between the woofer box tune peak and the low pass rise. So the net result is likely higher than the above "worst case" atleast somewhat.
I was just estimating Z min as DCR times 1.25
What is the Z min of a MAC-06?
I expanded the impedance curve and just used a ruler. It looks like the Z min might be 8.6 or slightly less. In that case my idea is a no go.
I recall talking to someone at Iowa DIY while looking at the specs and saying that its more like a 9 or 10 Ohm driver. So I'm thinking the DCR might be a misprint.
Not necessarily a misprint. A dcr of 7.8 is pretty high for an "8ohm" driver if you compare to others.
I'd think you would be able to pull off a safe enough impedance for a 4ohm stable amp once all the filters are in place. But then again that is me betting with your money
It is likely that over an ohm of series resistance will be implemented in such a design, provided you use air core coils.
I think you would be safe with three in parallel.