Which is better for a DBA (Swarm); powered subs or unpowered?

Ieales wrote: 

" DBA proponents are not charlatans, but neither are they correct as the the ability it to produce time coherent bass. " 

Arrival time coherence in the bass region is not critical, but decay time coherence in the bass region is. 

The ear is incapable of even registering the presence of bass energy from less than one wavelength. And the ear is incapable of registering pitch from less than several wavelengths. This from a Journal of the Audio Engineering Society paper which I no longer have access to. 

So the ear simply does not have enough time-domain resolution in the bass region to detect arrival time differences of a few milliseconds. 

So let’s look at the decay times. The longer a sound lasts, the louder it is perceived to be. So bass frequencies which take longer to decay sound louder. 

Also, since speakers + room = a "minimum phase" system at low frequencies (according to both Floyd Toole and Earl Geddes), when we know the frequency response, we know the time-domain response. Thus is it the peaks which take longer to decay into inaudibility. This implies that the frequency response is particularly important at low frequencies. 

Which indeed turns out to be the case. If we examine a set of equal-loudness curves, we see that they bunch up south of 100 Hz, such that a 6 dB change at 50 Hz is perceptually comparable to a 10 dB change at 1 kHz. This in turn implies that improvements in the frequency response in the bass region pay subjectively large dividends. 

In other words I believe that a good distributed multi-sub system addresses the issue that matters the most to the ears; namely, the in-room frequency response. 

Ieales again: "By FAT I mean that unless time correction is implemented the separate sub signals will arrive spread over several milliseconds... 

"IMO, it’s as unlistenable as MP3... 

At RMAF 2017 we displayed using a distributed multi-sub system in one of the standard (small) hotel rooms. An industry veteran cable manufacturer, with several decades of experience, handed us his thumb drive and asked us to play a recording of Fanfare for the Common Man. When it was over, he told us that was the most natural rendition of the tympani he had ever heard in any room at any audio show. He said it sounded just like what he heard when he went to a concert. 

(Incidentally in my experience the term "fat" is normally associated with a frequency response peak and its attendant long decay time, so it IS a time-domain issue - but applicable to the DECAY behavior, not the ARRIVAL TIME behavior. Our ears cannot react fast enough to hear "fat" in the arrival of bass energy).   

So I’m going to go out on a limb and claim that Ieales’ statement that a distributed multisub system is "as unlistenable as MP3" is an exaggeration. If he wishes to prioritize arrival time that is fine with me, we have a difference of opinion on that subject. 

Duke

I (hesitantly) decided to go with the Swarm after reading through the postings here (in particular from millercarbon and noble100) and other sources. These are very knowledgeable people with real world experience.

Now with all 4 subs singing, bass is extremely present, dynamic, fast and very clear. Everything I read in the posts were true and not exaggerated.

Indeed. 

I think I’ve decided to go with the Dayton SA1000 and two 10” or 12” passives; any suggestions on a decent quality sub for ~$300??? I’ve heard someone on this site recommend the Dayton Audio subwoofer kits on Parts Express ($265 for the 10” Ultimax, $311 for the 12”); has anyone heard them, or anything else in this price range?

Mine are the Morel 10". https://systems.audiogon.com/systems/8367
Two are the Parts Express sealed kits. The other two are the same kit, expanded vertically to increase volume because they are ported. I would not hesitate to just go with whatever Parts Express sub/cabinet kit you like. Just be sure to pay attention to impedance especially if you will be running multiple (4) off one amp.

This turned out to be one of the best swarm discussions thanks to the DBA detractors arguments and opinions

Cheeg, I'm not an expert on this matter just a learning user and by empirical evidence having experimented single and dual big not integrated subs before and a DBA of 4 smaller subs now I can tell you I prefer and advocate for the DBA big time.

By the way, although I respect the knowledge showed by the detractors of DBA and also respect (but not share) their opinions, their particular claim of "big bass" and "thump thump thump" and "appreciated by bass heads" IMO it is an insult to the DBA, one of the features of the DBA which I appreciate the most is that quite differently from single or dual non integrated subs the amount of bass you need is very very minimal per sub hence not "thump thump thump" at all. Sometimes you will hear the term "the subs disappear" in my case how I understand this "practically" is bass is "natural" like where u are going to an "acoustic" concert.

I use 2 SA1000 with 4 audiokinesis subs and gain on my amps (parallel connected) is at 50 percent on a 36 by 19 room

Oh one last thing if you are indeed a basshead one SA1000 with 2 (8ohm) subs in parallel will clip sometimes after 90 percent gain so using one sa1000 with 4 subs might be a challenging proposition

luisma31

... their particular claim of "big bass" and "thump thump thump" and "appreciated by bass heads" IMO it is an insult to the DBA, one of the features of the DBA which I appreciate the most is that quite differently from single or dual non integrated subs the amount of bass you need is very very minimal per sub hence not "thump thump thump" at all.

That sort of criticism of DBA is from those who haven’t heard it set up properly, or have not heard such a system at all. I agree that the one big advantage of DBA is the ability to create smooth, even, neutral bass. It is very appealing.

The price for that smooth, even, neutral bass is that your bass will be monophonic. That’s actually a small sacrifice to make because so much LF is recorded as mono anyway. The problem arises when DBA proponents insist that all bass is monophonic by virtue of it being non-directional. That widely-held belief - supported by claims in magazines such as Sound & Vision and Secrets of Home Theater - can easily be demonstrated to be wrong.

Still, mono bass can sound very, very good, and can lay a strong foundation for the rest of the music. I just prefer to have my LF in stereo, just like the rest of my system, and my speaker system is especially adept at achieving that.

@audiokinesis 

Duke,
Glad you joined! Would the ability to time-adjust each of the 4 subs improve sound? Like Toole described in his Sound Reproduction?

I've gone from 1 Rel to two sealed DIY 12" Rythmiks in a digitally active 4-way stereo system, where the subs play mono. I'm thinking of adding two more Rythmiks, which have a number of adjustments from the plate amp including phase. I was wondering if the addition of a box receiving the summed mono subs signal and adjusting time on each would further improve things vs "just" adjusting phase on each. 

Regards

After reading this post I had to join in . I will describe my sub bass system as I have implemented it I don't know if it is right or wrong but sounds great in my room . The room is a L shaped room in a Manhattan apt. the room is mostly concreate construction .12 ft wide by 18 long opening into a 12 x 12 entrance foyer . The system  is on the long wall for living arrangements . I am using 6 subs at present time . My sub bass system is controlled by a DSPeaker Antimode 2.0 for crossover , volume & room correction function . I run my subs in stereo . The two main subs are on Isoacoustics sub stands . The main speakers sit in top of the subs also on the same type stands all my speakers and subs are sealed . The main subs are REL Q201e that I converted to passive now being powered by a Crown XLS2502 amp . I run the fronts at a slightly higher volume then the other active subs in the room . I have the option of low or high level inputs to the DSPeaker and preferer the high level it sounds more cohesive . I can adjust the total sub volume , crossover & slope with a remote control .I have not done any measuring I just use my ears as I feel I am the only one to satisfy . RC