Upgrading sub to get a live feel.

@mcreyn, wow really good post. I'm actually restoring my '84 911 and was thinking of adding a car stereo system, but always wondered if I could ever get something that would sound close to what I get in my home system. I have to admit I am a bit of a dinosaur when it comes to car audio, but you have now sparked my interest to research this further.

On the home front my room is somewhat small, 20' x 12', and I have used a version of the swarm for the last few years that was inspired by some work Roger Modjeski at Music Reference was doing and the way in which he designed and ran his ESL speakers. I don't play loud, under 80 dB, no home theater, and most of the music I listen to doesn't have anything that extends below 30 Hz. I'm now upgrading the woofers to 10" housed in sealed boxes, and thanks to mijostyn who has posted on a few of these threads I have rearranged my swarm to be what he refers to as a line source bass array. We both use Acoustant speakers (his 2+2, mine Model 2) so his experience was helpful. In addition to my panels, I use a Beveridge RM3 crossover with 4th order 24 dB slopes for high and low pass, and biamp. I've been really pleased with the results so far and I'm looking forward to hearing what the upgrade brings.

Your experience though has me thinking about some other options for the future. In some ways perhaps active subs might be more beneficial for my next listening room. Rythmik is on my radar, but would be curious to know more about your setup and some pointers about using multiple active subs.

clio09,

For car stuff, I find simple is great. Check out CDT, Hertz, and Diamond Audio for components. For subs, Image Dynamics work well. For a car the size of a 911, an 8" will just cut it, a 10" if you can fit it. You can use speakerboxlite for free on an IOS device to model drivers in enclosures. Sealed works best in a car unless you are looking for max SPL.

Regarding your setup. Given your listening levels, you are not likely to be running into compression or high distortion levels. I will caution you with using sealed subs in a home environment, you will likely need to eq to compensate for roll off in excess of room gain. BTW, loved those Acoustats, remember hearing them driven with a Hafler front end (XL-600). Now I am giving away my age.

Sealed Rythmiks are an experience. The only way I can describe them is slightly dry, very clean, and great impact. In my office, I use their base L12 with a paper driver, which is slightly tighter and cleaner sounding than the HGS-12 it replaced.  In my main system, I used an F15HP, which is significantly tighter and cleaner sounding than the two HGS-12s it replaced, and crushes them in output).   Don’t tell Noble, but I am only using one right now in my main setup (after using two subs for a couple of decades). There is a second on the horizon, but my listening room has little in the way of standing wave issues at my listening position. This is driven in part by its large irregular shape (21 feet long, 13 feet wide for part, 19 feet in part, a ceiling that goes from 9 feet to 18 feet, and two large openings to other rooms). As a result, I have one dominate mode in the 40hz range that is easily addressed with a single band parametric eq. Two will provide a more even response, but some additional headroom (which is needed, as a certain wife has bottomed the Rythmik when in control of the volume, music, drinks and dancing).

As far as setup, lots of trial and error with REW and moving the sub (subs before) around and playing with phasing, cross-over, and PEQ. I have tried a Mini DSP after the crossover and did not like the results (but it could be I am not savvy enough with the setup). When I say trial and error, I probably ran 200 sweeps before I got everything dialed in. REW is a gift compared to doing it with a CD with tones, an SPL meter and graph paper or a spreadsheet. Well worth the cost of the UMIK ($100) and the learning curve.

https://www.roomeqwizard.com

@mcreyn, yeah Tim was interesting at first, but now it's gotten pretty old. I am a fan of Duke LeJeune's speakers having owned the Jazz Modules before finding ESL nirvana. So when he developed his Swarm I had always intended to give it a go, until I started working with Roger Modjeski and he convinced me to go down a different path. Either way it would have worked out well.

The active crossover is EQed and my Acoustats have been modified. Of the two panels in each speaker, one is actually Roger's ESL panel. They have also been modified to use the Acoustat direct drive amps. So no interfaces.

Thanks for the tip on the car system and software. I'll look into it further.

mcreyn:
"At the end of the day, it is not about hitting huge SPL levels, it is about getting the best sound, which requires using subs that can stay clean and not run into dynamic compression. 4 10" subs can't do this in a reasonably sized room. It is why my progression of home subs has taken me from Velodyne F series, through ULD's, to HGS, and finally Rythmik. At each step, it has seemed to be amazing (and better than anything I ever heard at a dealer), but the next step revealed more."


Hello mcreyn,
     I'm glad to read your comment that "at the end of the day, it is not about hitting huge SPL levels, it is about getting the best sound, which requires using subs that can stay clean and not run into dynamic compression".  This makes complete sense and I agree with this statement.
     I was questioning whether you had the knowledge and experience to realize the truth in your statement because you were mentioning earlier the ability of larger subs being able to reproduce deep bass at 115 db which is not necessary and can literally cause permanent hearing loss after about 30 seconds.  I wish you had made this statement earlier. 
     Your statement, "it is about getting the best sound, which requires using subs that can stay clean and not run into dynamic compression. 4 10" subs can't do this in a reasonably sized room", I believe also indicates that you have a lack of knowledge and experience of how well the 4-sub DBA concept actually works in any room and with any main speakers.  
     It's definitely true that the four subs in the AK Swarm DBA system are each relatively small (1'x1'x28"), weigh only 44 lbs, contain only a single 10" aluminum long-throw driver and are used in a room considered by most to be reasonably sized (my room is 23'x16'x8').  After using this bass system for almost 5 years now, I know with certainty this system is an excellent performer in the limited 20-50 Hz range that I require supplemental deep bass, my main Magnepan 2.7QR planar-magnetic dipole speakers provide excellent bass performance but only down to about 35Hz but it blends seamlessly with the deeper bass produced by the four Swarm subs that extends bass response of my system down to 20 Hz.
     I completely understand the skepticism from you and other individuals accustomed to utilizing fewer but larger traditional self-amplified subs in their systems.  I understand the lack of comprehension and justified skepticism because I initially lacked the comprehension of how this was possible and was very skeptical myself.  It took me a lot of research on the science behind the DBA concept, reading numerous extremely positive reviews on the AK Swarm and custom DBAs from professional reviewers as well as users and a lot of email and phone conversations with AK's James Romeyn to convince me to give it a try in my room and system.  
     I'm  so glad I did because I consider the bass the 4-sub Swarm DBA system provides in my system/room to be state of the art for both music and HT.  It honestly seems to me like I've learned about an audio secret and I now feel a responsibility to spread the word and let my audio brothers and sisters in on this almost magical secret.
     Of course, I realize the Swarm does not provide the optimum bass response performance that the DBA concept is capable of.  I believe the optimum bass response performance that the DBA concept is capable of would most likely be realized by a combination of our viewpoints, four very large subs with even greater bass extension and output capacity positioned in the room as a distributed bass array system. It's also possible that room correction, either of each sub individually or as a 4-sub group, could further optimize the performance of such a system.   
    I'm currently more than satisfied with the Swarm in my system/room, even though it's performance is a bit less than optimum for a DBA system, due to its combination of extremely good bass performance and its inconspicuousness in my living room.
    In my experience, I can definitely state with validity that the extremely high quality of the Swarm's or a good custom DBA system's bass performance exceeds the sum of its parts.  I'm convinced the factor that's responsible for this is the DBA concept's utilization of psychoacoustic principles that I've explained in detail on an earlier post on this thread. 
     How our brains process the existence of the abundance of bass room modes (many bass peaks and dips) produced by the 3-4 subs in a DBA system by summing and averaging the bass by frequency which results in the perception of the bass as being very accurate,detailed, smooth and natural while also being very flexible to reproduce whatever bass the source content calls for; fast, rhythmic and tight on music or sudden, deep,dynamic,powerful and impactful for music and HT.  

Tim