So It`s Ok To Mix and Match Ported and Sealed Subwoofers ??

Hello scm,

    I utilize a 4-sub Audio Kinesis distributed bass array (DBA) system in my 23'x16' room that also has rather large openings (4-5'x7' pass-thrus along the front of one side wall and at one side of the rear wall.) to other rooms but I have 8' tall ceilings that are not cathedral type.
    I'm fairly surprised that you're committed to using 4 or even more subs in your room and system since there are relatively and inexplicably few Audiogon members who have first hand experience using a 4-sub DBA system, ever personally auditioned one or are even committed to trying the concept. So, I am curious how you became committed to giving it a go.
    Don't get me wrong, you've made a very wise decision that I'm absolutely certain you will never regret in the least. I've been using my 4-sub DBA system for over 4 years now, initially with Magnrepan 2,7QR and currently with 3.7i planar-magnetic main speakers for both 2-ch music and HT, and its performance never fails to put a smile on my face on a daily basis with either. Prepare to be amazed.
    I'm willing to assist you at attaining similar results in your room and system if you'd like. On this post, I'll just give you some broad answers to your questions, provide some useful information and ask you
a few questions:

1. Both my Audio Kinesis Debra and the AK Swarm system are complete kit 4-sub DBA systems that are priced at about $3K, include 4 relatively small subs (the Debra's are 14.5"D x 12"W x 28"H and the Swarm's are a bit wider and squarer in shape), utilize 10" aluminum long-throw drivers, are operated in mono mode with bass extension down to 20 Hz +/- 3 dB, a 1Kwatt class AB amp/control unit that powers all 4 subs and are supplied with a set of 4 port plugs that allows for a choice of operating all 4 subs in either ported or sealed configuration.
    Unexpectedly, I discerned no significant difference in bass sound quality in either configuration but operate all of mine in ported configuration because I perceived the bass performance to have a bit deeper extension.  
    In my opinion, there's little sense in ordering a 2nd sub amp/control unit to configure the DBA system in stereo since humans cannot localize bass frequencies below about 80 Hz and virtually all commercially available musical content has the L+ R channel bass below about 100 Hz summed to mono, anyway.

2. It's possible to create a Custom 4 or even a more numerous sub DBA system utilizing any subs an individual chooses. These custom DBA systems can perform just as well or even better than either AK complete kit system, can consist of various sub sizes, brands, models, can consist of a combination of sealed and ported subs and only have a few downsides.  
    Depending on the particular subs chosen, one downside of a custom DBA system is it will typically be more expensive than either AK complete kit price of about $3K . Other downsides are that all traditional self-amplified subs utilized in a custom DBA are required to posses control settings for volume, cutoff frequency and continuously variable phase and these controls need to be set individually on each sub, rather than once for all 4 subs on the AK amp/control unit.

3. The AK and custom DBAs work incredibly well even without any room treatments, mics, equalizers or room correction software and hardware. However, all of these additional tools can be utilized at the individual's discretion and may or may not further improve bass quality performance. I can attest to this because I've been using my 4-sub AK Debra DBA system without any of these potential bass performance aids for over 4 years with stunningly good results. I consider this as the strongest evidence of the DBA concept's effectiveness. I have no doubt the 4-sub DBA concept will work equally well in your slightly larger room.  
     
    Nevertheless, I recently ordered about $3,500 in GIK room treatments with assurances that these tools will only further improve the bass response performance in my room. I honestly have a hard time imagining how the bass performance in my room, already what I consider to be near state of the art, could be even better but I'm very curious to find out; these should arrive next week and be installed within a week after.
     You may have noticed I haven't asked for any further information on your room, room treatments or the make, model or type of your main speakers. The reason is that none of this matters, the 4-sub DBA concept works extremely well in virtually any room, with any pair of main speakers and with or without assistance of room treatments or DSP of any kind.
    Okay, lastly a few questions for you:
1. Do you have a total budget amount?
2. How did you learn of and about the effectiveness of multiple subs?
3. Are there any reasons you want to use more than 4 subs in your room?
4. Do you have a preference for a complete kit 4-sub DBA or a custom one?


Thanks,
  Tim

Hello scm,

    I'm guessing you're using something like the Revel Gems as your main speakers but, as I stated earlier, it really doesn't matter. You didn't answer my question about your budget, so I'm guessing that means your looking to spend as little as possible.
    If you're mainly concerned with very good bass performance at your listening seat and want to spend as little as possible, One option would be buying another Revel Ultima15 pre-owned passive sub, use the crawl method to position each sub optimally and power them both with your Dayton amp.  
      Another fairly low cost new option is to sell your Revel sub and Dayton SA-1000 amp, buy a new or used pair of the good quality SVS self-amplified PB/SB 1000 subs (SVS may still have a pair of new SB-1000 subs on sale for $950) and optimally position both using the crawl method. With either of these options you could add another pair of subs later if you wanted to. I can describe how to connect 4 passive subs to your Dayton amp in series/parallel when and if you want to in the future.
    The only downsides of using self-amplified subs is that you need to make sure the subs have separate controls for volume, crossover frequency and continuously variable phase(I know the SVS SB-1000 subs do) and you need to set these controls individually on each sub, rather than once for both/all 4 subs when powered by the Dayton amp.
    A third option is to deploy 3 subs, which Dr. Earl Geddes claims can be as effective as 4 subs if properly positioned and configured. This may be best for your system since the subs don't need to match in brand, model or size and you can mix self-amplified subs with passive subs.

Tim

Hello scm,

     Excellent, from what I've read, the HSU ULS-15 mk2 are a very good choice.
    I suggest you first setup and audition a custom 3-sub DBA system in your room, using your 15" Revel/with Dayton amp and your 2 15" HSU mk2 self-amplified subs.  
     It's important to position each sub optimally in your room.  I think using the crawl method, starting your search at the right front corner of your room and moving counter-clockwise around the perimeter of your room, should be sufficient for positioning each sub but you're welcome to use a more sophisticated method if you have the equipment and know how to use it.
     Once all 3 subs have been optimally positioned, proper setting of each sub's volume, crossover frequency and phase controls are the next critical steps.  Ideally, your goal is to have the volume of the subs match the volume of your main speakers and resist the urge to turn their volume up too high, you only want the subs to be active when the musical content demands it.  I've found it useful to set the volume as low as possible with the bass still sounding powerful, dynamic, detailed and natural.
     For the cutoff frequency settings, I suggest running your main speakers full-range and initially setting this control on each sub at about the rated bass extension frequency limit of your main speakers.  You can then adjust this setting slightly upward and downward until each sub is perceived as seamlessly integrated with your main speakers. 
    For the phase settings, I suggest you initially just set each to the position the bass sounds best to you.  I don't think this setting is as critical as the other 2 but I can detail more precise methods of optimally setting the phase on each sub if you'd like.
     I'm more than willing to further assist you when your new subs arrive if you'd like.  Just let me know on this thread or PM me.

Tim

Hello Steve,

     I consider fun and enjoyment the only results that matter in this crazy hobby.

Enjoy,
Tim

Hello Steve,

     Okay, good.  You should be aware that I went from 2 subs to 4 subs in my system search for high quality bass.  I've never tried 3 subs but one of the most prolific acoustic researchers and advocates of the 4-sub DBA concept, Dr. Earl Geddes, has stated that 3-sub DBAs can be as effective as 4-sub DBAs if the 3 subs are properly positioned and configured, with configured meaning the volume, crossover frequency and phase controls are optimally set.
     I have no reason to doubt that 3 subs can work well but I can't help thinking that optimum positioning of each sub is likely more important when 3 subs are used than when 4 subs are used.  I have complete confidence in the crawl method of sequentially positioning each sub in a room, since I've used it effectively in my room with 2 and 4 subs, but wanted to make sure you're aware of exactly how to do this.
     I'm also thinking that you have the option of creating a custom 4-sub DBA system, by including your smaller 10" self-amplified sub as the 4th sub, if you'd like.  In other words, your room is large enough that I'm fairly certain that 3 large subs will provide high quality bass throughout your entire room, if precisely positioned and configured, but I'm very close to certain that 3 large subs and a 4th smaller sub will do so.
     I still  think a good plan is to setup a 3-sub DBA system, closely evaluate the results for a few weeks and progress to setting up a 4-sub DBA system only if you're not completely satisfied with the 3-sub DBA system results.


Later,
Tim