The 8mm bolts provided by Stack fit on the F12.
What’s your cross over point and volume setting for pairing with the FR30?
Is stack Audio now shipping these from the U.S now? I thought I read somewhere they now have a distribution location here now.
Still experimenting with all adjustments and locations. I anticipate getting an additional two F12’s (total 4) next month. So, a final x-over and output point is well in the future.
I asked Chris the same question months ago, for a starting point. His recommendations were different than my current settings. I would suggest that system and room differences are such that only your tests will reveal the best settings.
I believe so, but best to see for yourself.
My 3rd F12 sub arrives tomorrow.
Initially I plan to keep using 70-75 hz for the low pass filters, with 24 dB slopes, positive polarity, and 0 phase for two subs along front wall. One sub is in the right front corner, the other is about 1/3 room width from the left corner. Both are on ASC sub bass traps and sit 1-1/2 ft above the floor. I don’t recommend putting the subs directly between the main speakers if they are FR-30’s, as it constricts or blurs the nice soundstage created by the passive woofer radiators and can add to negative room mode issues.
The 3rd sub will go in my left rear corner area. Because it is closer to my listening position, I will add about a 3ms delay to it to make sure I hear sound from the mains and subs in front first, to keep timing better balanced. The 3rd sub is mostly to reduce room modes and add to room dynamics. It may even get moved to the left rear side at some point if REW indicates a benefit in reducing remaining dips in frequency curve. Not sure about phase settings on it yet.
A 4th sub for the right rear is a future possibility. If I do that, a double bass array may be worth trying, but so far 3 subs spread around do balance out room modes quite well.
I may consider reducing the low pass filter of the rear sub to 40-50 and increasing its volume level slightly to see if lower bass frequencies develop below 25 hz that may improve the overall room sonic feel.
There are so many options with the PS Audio sub app, that even with REW and mics, it can take quite a while to sort out the best setup. Then the cables, subs, speakers, and components break in more and revise the entire sound. At first, I was thinking things were too bright with new Front Row Reserve cables on the mids and high frequency panels, but with the new PS Audio preamp, and more time playing, these initial hardness issues are no longer a factor, and everything sounds better than ever.
I am on dense padded carpet on a concrete slab and so I have not really needed to play with different feet. The subs already have soft feet, as do the ASC sub traps. Very little vibration gets transferred that degrades musicality.
The key is to realize the system sound quality changes over time and no one setting stays perfect. On many songs just increasing the volume can drastically impact how things sound and blend together, and will impact your desired settings.
has anyone compared these to REL S/510? asked REL if there new line was backward compatible for stacking, they said ‘no’ but can trade in at some dealers…. not gonna happen
so seriously considering a F12 stack (4 or 6? wonder what PSA recs)
I would have to get a 2nd REL Carbon Special before I would ever consider stacking subwoofers. I am sure my neighbors don’t want me to get a 2nd subwoofer, lol.
They are very different beasts—the Foundry is a sealed sub while the REL’s use a passive radiator.
They are both excellent but to my ear, Foundry is tighter, deeper, and more musical.
Because Foundry has twice the amp power and is a sealed design that digs deeper in the bottom end, a 4-pack competes beautifully with a REL 6-pack.
mahalo very much for that - good to know - am music first, so pretty sure I would enjoy the difference - and so far every single PSA addition has been an amazing improvement to my listening experience
i will tell my wife how much we are actually saving when I eventually do pull the trigger 
If I’m not mistaken the idea of the six pack is not increase bass but to fill the listening area floor to ceiling or heighten the bass image. So I would imagine a 6 pack of foundry subs would do the same.
I haven’t used the carbon special but that looks like the one to get (good amount of power and the driver looks like it has more motor behind it).
The setup and room integration is the biggest challenge subwoofers have and the main issue I have with REL subs. Just gain and crossover aren’t enough to deal with the complex interaction of the subwoofer/room/speaker. In addition to having a musical sounding sub, I think DSP and flexible adjustments are the critical factor needed in getting good in-room results.
Bass waves aren’t directional and even stacking a few subs doesn’t significantly change that. The acoustic source is very small compared to the wavelength. Even up at 80 Hz, it’s a 14 ft wave and, until you get the acoustic source close to the size of the wavelength it’s playing. Stacking things even to 5 ft tall has essentially no effect on directivity. It can effect the vertical room modes slightly (the floor to ceiling stuff around 100 Hz in a typical room) but 99% of what it does is output related.
I was looking for some infographics about wavenumber and directivity vs source size vs frequency and didn’t find much except I found a graduate level acoustics course for free at MIT that talk about a bunch of this but is a little math heavy.
Pretty cool
I agree with this 100%! I had an endgame dream of 6pk subs but after I was introduced to Bacch I believe the Bacch4mac setup may of ended that desire. The Bacch DSP places bass in the room perfectly and I’m not sure the addition of 4 more subs would add or change much from what I’m hearing now.
Well, room related response dips often can’t be corrected with EQ because they are the result of a cancellation. Driving the room from a different location can fill these in, which is where multi-sub comes in. Also, mutli-sub is about minimizing response variation seat to seat which is more about multiple listeners and sometimes TV/movies. BACCH is really a “head in a vice” single person experience may not be worried about the seat to seat variation as much.
You are correct about this aspect. My speakers being ML electrostats by their design are a localized or head in vice experience. With Bacch it is the same so the two together are a perfect match! If there are two listeners in the room we have to sit like we are in the cockpit of a jet. Luckily the back row is elevated. Since 99% of my listening is by myself (I have no friends) it works great. If I get more than one friend listening at the same time I may have to reconsider the 6pk. Lol
Since 99% of listening is with my wife, it’s an important reason why I’ve deferred from spending much time considering BACCH. Heard it multiple times (calibrated to me). It’s quite effective. Just doesn’t bring a lot of value to our particular music experience.
I guess you could calibrate with the left in ear mic in your left ear and right in ear mic in your wife’s right ear and press the fire button to calibrate sound for you both. Lol
Seriously tho I apologize if I’m side tracking the thread I’ve heard Bacch with Alysvox speakers and yes it was better in the sweet spot but no one was suffering sitting anywhere else in that room. An old wise man said that it sounds even better since the time I heard it. When Bacch was placed on bypass the whole room went flat. It was sad.
I just hooked up my 3rd F12. Two are in diagonal corners, and another is 1/3 along the front wall. All are on 18-24-inch ASC sub trap stands to gain height, trap excessive room bass gain, and they help with reducing vertical room modes.
The 3rd sub replaced a 17-inch SVS Ultra sub and the immediate improvement surprised me. The main FR30’s overall sound quality improved and all of the bass became tighter and clearer. All the music, even voices improved.
Before I could tell there was a sub in the back wall area, but now with the ms delay on it, that the SVS did not have, everything sounds correct like it is all from the front soundstage. The musically that has been mentioned about these subs is real.
100% agree with Chris, the DSP and flexible adjustments on the F12’s are critical. The new SVS 17 Ultra is highly rated, but it can’t compare with the sound of the F12 and its ability to better match the room which is the main factor in getting the bass to sound right.
The app has a standby mode in system settings. The manual talks about a “timeout” function. I tried the app standby set at 1 hour (default is never), but the lights stayed on and the heat sinks were still warm after several hours.
The manual may need to be revised. How can I tell the standby is working?