I would love to see it, if nothing else, it helps me to see other ways to do crossover. I appreciate it's useless without the baffle, totally. But again from the stand point of comparing to how you would approach it for crossover vs what I did is a good learning point for me.
My sim with the RS225's, I'm getting kind of close to 3ohm in a few spots.
The 6PT version I'm at 5ohm or better the whole way.
So again just learning stuff from others' sim work.
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Currently, costs would be:
Passive RS225 approach:
Need 4 x RS225 woofers ($65~80 a piece depending on sales) = $260~$320 in drivers.
I already have the PT6816-8 planars and the 4" ports
= $260~320
Active sub approach:
Need 2 x GRS 8SW4HE's ($40 each) = $80
I already have 2 GRS 8SW4HE's on a shelf, ready to go
I already have 2 PT6816 planars.
Need 2 x GRS 6PT-8 x 2 ($17 each) = $34
Need 1 x plate amp ($150 for the 300W with the bass boost at 30hz)
= $264 total to get this up and running
So, almost the same cost to go either direction. One gives me very good 30hz output with dedicated integrated subs in the towers. One is totally passive and doesn't need a bunch of plugs.
Very best,
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Here is my sim with dual RS225-8s in parallel.
Note, the frequency response and zma for the RS225's are actually real measurements on a 10.5-inch wide baffle with 1-inch roundovers. (The roundovers won't matter for the woofer frequencies) but the GRS Planar are simmed. My speaker was undersized and had an F3 of 37Hz but the RS225s can go lower, although I'm not sure an F3 of 34Hz vs 37Hz matters.) Note, predicted in-room response (orange line in the Power and DI pane) is not very close to the pink target line, but I think the off-axis simulations of the planar may be worse than reality here. Crossover is around 1.2khz based on yesterday's discussion regarding how low the planar can probably go in reality.
Note, the frequency response and zma for the RS225's are actually real measurements on a 10.5-inch wide baffle with 1-inch roundovers. (The roundovers won't matter for the woofer frequencies) but the GRS Planar are simmed. My speaker was undersized and had an F3 of 37Hz but the RS225s can go lower, although I'm not sure an F3 of 34Hz vs 37Hz matters.) Note, predicted in-room response (orange line in the Power and DI pane) is not very close to the pink target line, but I think the off-axis simulations of the planar may be worse than reality here. Crossover is around 1.2khz based on yesterday's discussion regarding how low the planar can probably go in reality.
Thanks! That's very interesting. I will practice more with the baffle and enclosure editors in the software to see if I can do similar and get a better idea of things with an intended baffle size. If I stick to 8's I can come down to about 10 wide baffle. Either way, 10" wide, 50~55" height, variable depth is fine.
The other consideration is driver placement. Having the drivers all together in the center of the baffle isn't always the nicest looking. I'm not sure if it would be better to do Planar -> Woofer -> Woofer -> Port from top to bottom centered on the baffle close together. Or Woofer -> Planar -> Woofer -> Port top to bottom. Or, if I did the active version, Planar -> Mid Woofer as a unit towards the top centered up. Then near the bottom of the baffle on the front, the Subwoofer -> Subwoofer ganged up.
Very best,
So, I've been wanting to do this...How good is the simulation?
Here are actual measurements, RS225 only, on a real baffle in a real cabinet.
Here are simulations in VituixCAD using Dayton Audio's on-axis file provided in their zip file of the driver on an infinite baffle, simulated on a 10-1/2 inch wide baffle with 1-inch roundovers.
And if I drop the simulated measurements into the exact same crossover in post #102, I get this.
So, as WhiteDragon pointed out yesterday, we should make sure not to take our simulations too seriously, but they can still be useful before buying drivers and building a cabinet.
Here are actual measurements, RS225 only, on a real baffle in a real cabinet.
Here are simulations in VituixCAD using Dayton Audio's on-axis file provided in their zip file of the driver on an infinite baffle, simulated on a 10-1/2 inch wide baffle with 1-inch roundovers.
And if I drop the simulated measurements into the exact same crossover in post #102, I get this.
So, as WhiteDragon pointed out yesterday, we should make sure not to take our simulations too seriously, but they can still be useful before buying drivers and building a cabinet.
Understood and agreed. I like to simulate and model what I can for that reason--to even see if it's worth putting them together to measure in the first place. It's very useful to know that they're at least an ok match for the goal at hand. Without this, its not that easy to just throw things together without a lot of trial and error without incredible experience. This helps "shop" for things that lead to the goal.
I'd rather sim two or three hundred times and buy once! 😊
For now I just gotta sort out if I want active sub drivers or a passive tower. I like both ideas. Cost is about the same. I'm torn on how I want the driver arrangement to look.
Very best,
To be honest, if you want to use the planar with two woofers as a two-way, there is only one way how to position the drivers.
No other option but W-T-W from top to bottom. This is no matter of taste, but dictated by physics. Yes, physics is a dictator, cruel and unforgiving.
No other option but W-T-W from top to bottom. This is no matter of taste, but dictated by physics. Yes, physics is a dictator, cruel and unforgiving.
I was afraid of this. I wouldn't mind it being an 8" woofer then 8" planar then 8" woofer, towards the top of the tower. But if it has to be equidistant spaced over the entire baffle that will be weird. If it were W-planar-W and then port, that would look really weird I think on a big tall baffle like this.
If I can do woofer + planar near the top of the baffle without issue, and the subwoofers at the bottom, that may be what decides things.
I'd like the planar and woofer to at least be around typical ear height, in my room, so around 30~40" is a good range in my living room for height for location of the planar and woofer. The sub can be lower down, won't matter as much.
Very best,
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Please explain the physics you referring to, would be interesting. Most speakers are W-W-M-T bottom to top, then again they are all idiots. Some have woofers all in one box and mid tweeters side by side in another (infinity RS1). I have infact only see center channels with W-T-W that is supposed to lie on its side. Why does everyone not follow your theory.
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I at least know the spacing matters and position matters, based on wavelength and how they will interact, etc, diffraction from the baffle and all. If I put a woofer on the top and bottom of a 55" baffle and the planar in the middle, that would be weird and have a lot of ugly effects I think. I think I could put them W-P-W in the middle of the baffle tightly grouped though. And I think I could put them grouped like that at the top of the baffle too without too much problem. I think.
Very best,
Ok, after hashing it out with a friend, I think I'm going to go down the path of least resistance with knowing I want a strong 30hz output ability, which requires powered subwoofer drivers instead of passive stuff and the means to DSP/EQ. So I'll do the active route on these towers. I'll do the planar and mid woofer as a TM pair and 2 subwoofer drivers, sealed, for the low end with a separate amp with low pass filter, targeting around 120hz crossover or so if needed.
I ordered the few drivers I needed to complete this and will build the enclosure and install the drivers. Then measure them. Then come back and work on building a crossover from the measurement data so its precise to the actual drivers in the actual enclosure on its actual baffle.
Thanks all!
Very best,
I ordered the few drivers I needed to complete this and will build the enclosure and install the drivers. Then measure them. Then come back and work on building a crossover from the measurement data so its precise to the actual drivers in the actual enclosure on its actual baffle.
Thanks all!
Very best,
I figured I'd see the reality between the MB620 and 6PT-8. I already did a build with a planar and MB1025 and it's great. So will see which does well there and if I need to add another or pad the top to match, etc. Will start with the 6PT-8 and see what that looks like. Keeping it low cost as most of this budget will actually end up going into the live oak slabs and some epoxy.
Very best,
Now while waiting for stuff to arrive, I need to plan the baffle arrangement and aesthetic.
Or...
I thought about dual opposed, but figured, it won't be that wild with fairly low excursion, so I'm not worried about it. It will be on a footer too. So no worries about it wobbling. Mainly just need to sort out if I want it to be Woofer-Planar or Planar-Woofer.
Very best,
Or...
I thought about dual opposed, but figured, it won't be that wild with fairly low excursion, so I'm not worried about it. It will be on a footer too. So no worries about it wobbling. Mainly just need to sort out if I want it to be Woofer-Planar or Planar-Woofer.
Very best,
Yes, lots of options, I'm thinking it will largely be based on the ear height position average in the room where I place the planar since it has the least vertical plane off axis tolerance. The baffle will be over-sized to allow more of the live oak slab to be seen. If it were not for that I'd happily fill the baffle with drivers and minimize the baffle needs. But, this will be seen heavily in the living room, so wanting emphasis on the oak wood baffle that it will be built into.
Very best,
As a general rule, the nearer the drivers are, the better. This is of higher importance, the higher the crossover frequency is.
If you want a smooth running build, your sketch at the top is fine. The second idea enlarges the distance mid to low and will have consequences.
I know there are commercial builds like that, but you don't see what has been done to compensate for this inside and did not hear what negative results it may have had. So better go the straight way, instead of suffering from self made problems when doing the crossover..
If you look at commercial subs and plate amps, because of this problem you will find a phase switch or rotary knob to correct for the distance to the main speaker. In a DSP you may use time delays to correct for this.
If you want a smooth running build, your sketch at the top is fine. The second idea enlarges the distance mid to low and will have consequences.
I know there are commercial builds like that, but you don't see what has been done to compensate for this inside and did not hear what negative results it may have had. So better go the straight way, instead of suffering from self made problems when doing the crossover..
If you look at commercial subs and plate amps, because of this problem you will find a phase switch or rotary knob to correct for the distance to the main speaker. In a DSP you may use time delays to correct for this.
Great points, thanks! I'll move things around to see what looks good. It also will matter what size oak slabs I end up with. I can shift it all down and reveal more oak slab above the drivers too. No rules there. But definitely want to keep a lot of visible baffle. Taking that point of the mid to low crossing to heart, that's a very good point, will rearrange to keep the woofers near.
Very best,