The dipole subwoofer-How does it works

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I use magneplanar tympanis, and my audio buddy also uses them, albeit with the addition of a H frame dipole sub (2 x 12 inch drivers).

After using boxless speakers for the last 15 years or so, I can say IMHO that any speaker with a box sounds awful. They all have resonant modes that are clearly audible if you are used to listening to dipoles. I have learned to hate box speakers as I find these resonances highly distracting.

So there are efficiency penalties with dipoles. But what the the heck, is this forum about the most efficient speakers, or the best sounding speakers?
 
snip I can say IMHO that any speaker with a box sounds awful. They all have resonant modes that are clearly audible if you are used to listening to dipoles. I have learned to hate box speakers as I find these resonances highly distracting.

So there are efficiency penalties with dipoles. But what the the heck, is this forum about the most efficient speakers, or the best sounding speakers?
Exactly my sentiment. Boxless speakers will put better sounding music into your room. Which is why the "design" keeps so many adherents despite the obvious downsides.

Next best, however, are large sealed boxes used for subs.

I would say that plain raw drivers hanging from the ceiling on a string is needlessly extreme - but you'd be surprised how nice that sounds. Easy to try it, eh. But for subs, it is feasible to add enough baffling to keep from needing the monumental Linkowitz boosting without harming the sound too much.

My own OB sub is helped by the free-air resonance of the driver which perks up the range below where the baffling "gives up" and results in pretty nice woofing.

Learned AES research not withstanding, I think the dipole concept posted initially (perhaps invented just for patenting as unique??) is just snake oil and adds nothing to just having multiple drivers mounted here and there.

Ben
 
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Hi,

Having just cross read above the thread, it seems to me that both the pros as well as the cons generalize too much. This generates errored or flawed views about the topic.
I think we should clear first what the working range of a sub is.
Is it a true sub if the upper bandwidth limit reaches to 50, 80 or 100 Hz?
This makes imho a decicive difference.
If we postulate a range of lower than 50Hz, I'd rather sympathize with the Cons.
Here a dipole bass is terribly inefficient, requires enormous ampunts of moved air volume and still doesn't achieve the authority of a boxed bass.
In theory the dipole has no output at all in this range, due to beeing a velocity- and not a pressure transducer, while the bixed sub may even profit from room gain. Sonically the dipole subwoofer certainly leaves something to wish for, especially the larger the room becomes.
So I' also dismiss a dipole for a subwoofer, in the sense that a subwoofer only has to deal with the two lowest octaves. At these low frequencies a closed sub is advantageous in nearly every respect. Smaller, much more efficient, more authority, less building effort, more convinient, and imho superior sound quality.

Things improve and even change above 50Hz though. With rising frequency the efficiency of the dipole rises and surpasses that of a boxed speaker. Also the exitation of room modes is different, especially if tall, stacked systems are used, which eventually lead to a dipolar cylindrical distribution character. This gives You additional freedom in a room related parameter.
Sonically the dipole bass plays very authentic and natural, with a punchy kickbass. In a range above 50Hz the dipole unites more advantages and is imho the superior sounding device.

jauu
Calvin
 
At 159Hz it is not a sub, it is a bass speaker.
At 21Hz it is not a sub, it is a bass speaker.
If we need to differentiate ranges of bass, then how about we use the terms: low bass for 20 to 49Hz, mid bass for 50 to 99Hz and upper bass for 100 to ???Hz.
What is the frequency where we are agreed that it is no longer "bass" and has become "midrange"?
What do we call frequencies below 20Hz?
infra, sub, below?
 
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At 159Hz it is not a sub, it is a bass speaker.
At 21Hz it is not a sub, it is a bass speaker.
If we need to differentiate ranges of bass, then how about we use the terms: low bass for 20 to 49Hz, mid bass for 50 to 99Hz and upper bass for 100 to ???Hz.
What is the frequency where we are agreed that it is no longer "bass" and has become "midrange"?
What do we call frequencies below 20Hz?
infra, sub, below?


So my 2 LMSR-15's per side are bass speakers when ported and subs when they are sealed.

A subwoofer is anything that augments the low end of your main speakers. If your book shelf speakers are flat to 45Hz then 20-45 is under that bass speaker. I think its a sliding definition. I know everyone with a sealed LMS-ultra 18 wants to be in a different category. That's ok.

Since there aren't any subs that are meant to play 10-20Hz with nothing over 20hz, I think its fair to say that 20-80hz is part of what a sub does, or in most cases, everything a sub does.
 
Hi,

I generally cross the sub at 160 Hz
You must be Bose then? :bomb:

I´d orientate at the octaves.
16-32-64-128 with the first 2, max. 3 octaves as sub-range, and the fourth octave from 64-128 beeing bass. Anything above I´d call mid-range as Human voices starts here.
Keep in mind that the note a´ at 440Hz is already the acoustical mid-point of human perception.

jauu
Calvin
 
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Joined 2004
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Hi,


You must be Bose then? :bomb:

I´d orientate at the octaves.
16-32-64-128 with the first 2, max. 3 octaves as sub-range, and the fourth octave from 64-128 beeing bass. Anything above I´d call mid-range as Human voices starts here.
Keep in mind that the note a´ at 440Hz is already the acoustical mid-point of human perception.

jauu
Calvin

Nelson Pass and Linkwitz and many others must be Bose too...
very funny Calvin, Nelson crosses at 150 Hz
I got nice article about 160 Hz being scientifically perfectly fine to cross the sub to satellites, but the article is in Slovak, figures however might be enough to illustrate the point, I may scan it, if I will not be lazy...
 
........ its scientifically known fact, you can not localize sound up to `160Hz ...........
I posted a report a few years ago that my bass only speaker (dual 18") was crossed @ 150Hz and located off the the right of both satellites. I could NOT locate any of the stereo as coming from the bass only speaker.

I have seen many posts suggesting that the "stereo" effect can only be excluded by crossing a full octave lower to the bass only speaker, i.e. @ 75 to 80Hz.

What are your experiences, when using a single bass only, for a pair of satellites?
 
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