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They do not. There are many examples of flow resistance enclosures that generate cardioid response, ME Gethain, Music & Design (John K), http://kimmosaunisto.net/CardSub/CARDSUB.html etc.
EQ is probably still called for, I think I saw 10 dB at 30 Hz mentioned in the article, but I haven't yet taken the time to really read it closely.
Yes, unless using a high Qts driver or specialized one like from AE et al, just like many sealed subs, a bit of EQ is needed if one wants to get really deep.However, there is really no benefit to doing so below 40 hz or so, where modes are sparse. There, monopoles still rule, as many as one would wish. Even in mono. The research I linked does not suggest otherwise.cheers,AJ
No, I think at the time no one had even thought about a swarm approach, let alone tried it. As you know from my RMAF reporting, I do really like the AK Swarm
Mainly my point was more of a "be careful what you wish for", especially with high output low bass. For me, room pressurization was a very real negative.But I think a lot of people haven't had a super high output low bass system and might end up with a nasty surprise if/when they finally get one.
AJ & Duke,Below 40 Hz where you are dealing with very few modes, yes, large psychotic monopoles are key. But as far as the area from 40 Hz to a little below the Schroeder frequency of the room, can we agree that this is the modal region and that another option (other than multiple asymmetrically placed monopole subs receiving a summed mono signal) is a pair of cardioid subs receiving a stereo signal. This cardioid sub pair can then maintain spatialization and minimize the FR ripple as well as multiple assymetrically monopole subs?
Which is the best Guys,dipole or multiple monopole subs,too much tech jargon ,for us with limited tech knowledge,my opinion is the bass should be at the same loud level and spatial level as the other drivers...
It seems like, based on this conversation if I'm reading it correctly, that the answer is actually a combination of the two. Assuming we're talking about a two-channel stereo setup, the ideal appears to be a pair of stereo subs (ideally cardioid in radiation pattern, although a dipole would seem a desirable second option due to similar pattern control improving issues dealing with room modes) playing down to roughly 40Hz. From there to as far down as one would like to go, the research AJ references suggests a distributed set of monopole subs (like Duke's swarm setup) is the way to go, as sound localization no longer stands as an issue.
This combination of subs would theoretically present the smoothest, most even response below a frequency where spatial perception fails people, while maintaining proper stereo separation and imaging between there and up to where whatever chosen main speakers are in the system take over.
The interesting wrinkle in bass management presented so far in this discussion suggests that between 130Hz and 40Hz-ish there is a great need for processing and EQ to make that range work well with the stereo pair of subs, but below that, saturation to even out room response through summed dissimilar sources is key to the exercise, with whatever little processing or EQ one chooses to do being mostly a function of calibrating the swarm of lowest frequency subs to most optimally compensate and correct for each other.
A well set-up multiple monopole system does a very good job of having the same loudness level across the bass region. It also can have very good spatial level, with a little bit more cost and complexity.But I would not try to tell someone what is "best" without knowing a lot about their situation, because what is best for them depends very much on the situation.
I'm been looking for examples of cardioid subwoofer setups. Do they require DSP? It seems like that is a way to do it, but I get a lot of odd ball things that are just canceling phase of everything behind the subwoofers from what I can tell.
I've never listened to multiple subs,so i don't know what you're talking about,my situation is average room,i'm interested to know about the spatial of multiple subs and how they work,is it the same with surround sound?,thanks Duke...
Yes, they do require EQ/DSP. Read Music and Designs primer here: http://www.musicanddesign.com/NaO-II-U-frame.htmlAnd here: http://www.musicanddesign.com/u_frame.htmlJohn Kreskovsy has done quite a bit of work with cardioid designs. Best,Anand.
I will try to explain without using too much tech jargon.The worst problem that a single subwoofer has is, what the room does to its frequency response. As the bass energy bounces around the room, the reflections combine in a way that causes peaks at some frequencies and dips at others. We can move the subwoofer or move the listening position and that changes the peak-and-dip pattern, but does not eliminate it. The main idea of multiple subs is, to solve this problem. The peaks are the worst part if this problem. In the kind of multiple sub system I manufacture, the four subs are scattered around the room. If we look at each sub all by itself, the room will cause its response to have big peaks and dips. But the peaks and dips are at different frequencies for each sub because they are each in a different location. All of these different peaks and dips added together actually result in much smoother response than we could get from just one sub, no matter how carefully we position it. And no matter where you are in the room, you have the sum of four different peak-and-dip patterns, so the bass is smooth throughout the room. And smooth bass sounds "fast", because it is the peaks that sound slow. To answer your other question, multiples subs usually are not like surround sound, where each speaker gets a different signal. Multiple subs usually all get the same signal.
It drives me nuts there's no pictures of his subwoofers. And his have no DSP. As nice as they are in graphs, I'd have to hear them to know if the bass actually sounded good with all the dampening; so perhaps DSP makes more sense.Then again the swarm is pretty easy
Below 40 Hz where you are dealing with very few modes, yes, large psychotic monopoles are key. But as far as the area from 40 Hz to a little below the Schroeder frequency of the room, can we agree that this is the modal region and that another option (other than multiple asymmetrically placed monopole subs receiving a summed mono signal) is a pair of cardioid subs receiving a stereo signal? And that this cardioid sub pair can then maintain spatialization and minimize the FR ripple as well as multiple assymetrically placed monopole subs?
I need to download that paper AJ linked! And I need to become an AES member!
