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-   -   Cardioid Bass.... yes, very good!! (http://www.diyaudio.com/forums/multi-way/221153-cardioid-bass-yes-very-good.html)

gainphile 8th October 2012 02:13 PM

Cardioid Bass.... yes, very good!!
 
I have been very much appealed to the discussions around Cardioid Bass. More complex to design than dipoles, yet they seem to promise good things when compared to monopoles or dipoles:

1) Least affected to room positioning
http://www.wvier.de/texte/Beneficial...20Coupling.pdf

2) Able to pressurise the room
www.diyaudio.com/forums/multi-way/145876-measured-monopole-dipole-room-responses-13.html#post3188523

3) I had a listen to Musikelectronic Geithain 901K


A W-Frame dipole can be converted to Cardiod quite easily by sealing one of the woofer and equalise accordingly.

DIPOLE Setup:

https://lh3.googleusercontent.com/-9...593/dipole.JPG


CARDIOID Setup:

https://lh6.googleusercontent.com/-9...3/cardioid.JPG


Equalised response to meet 20hz, Q=0.5 target.

Note: NO LOWPASS XO in this graph.

https://lh3.googleusercontent.com/-V...42/Cardoid.png


I will need a good day and spare time to get outside polar measurements but a quick listen at the back of the speakers is quite revealing.


The Cardioids have punchy bass, something I miss when listening to dipoles. I'ts also as articulate.

In short, I like it !!

markus76 8th October 2012 02:37 PM

Did you also measure the in-room response around the listening position for both configurations?

john k... 8th October 2012 02:41 PM

By sealing one woofer of the W frame you end up with a monopole and a dipole. This alone does not sum to yield a cardioid. The dipole and monopole must be individually equalized to have the same axial response. From you post it is not apparent when you talk about Eqing to meet your target is that is what you did.

But, as you know, I've been on the cardioid wagon since the infroduction of the NaO 10 teas ago.

[edit] Additionally, to get it "perfect" with that apporach the AC of the monopole must be at the axial center of the dipole.

RockLeeEV 8th October 2012 02:46 PM

What's with the massive peaks at 600/1200/2400 hz? Cavity resonance? Mind showing the effect of stuffing the dipole section a bit with a thin layer of fibreglass?

Draki 8th October 2012 05:46 PM

Question, hopefully not OT: what is the rule (formula) for the bass drivers which can be used horizontally?

DrDyna 8th October 2012 05:56 PM

Quote:

Originally Posted by Draki (Post 3193950)
Question, hopefully not OT: what is the rule (formula) for the bass drivers which can be used horizontally?

Sag percentage, it's like...3% or less? something like that.

Edit: It's 5%.

DrDyna 8th October 2012 06:02 PM

Gainphile, what speaker is that? It's gorgeous.

Edit: Found it on your site.

Draki 8th October 2012 10:40 PM

Quote:

Originally Posted by DrDyna (Post 3193970)
Sag percentage, it's like...3% or less? something like that.

Edit: It's 5%.


Thanks DrDyna, in the meantime found this : Parts Express - Subwoofer Qualification Formulae For Downfiring Configurations

Turned to be 2,7% so guess OK for up-down mounting.

tinitus 8th October 2012 11:16 PM

I would never do that

though it is said that a woofer is more happy moving out than in
interesting to know if playing up would help it :scratch2:

studiotech 8th October 2012 11:36 PM

Thanks for the post Gain! At what distance was your measurement taken? Am I correct in assuming that the measurement was taken down low in front of the woofers and that's why the mids and highs look so off?

I am going to experiment with trying to get more of a cardioid response from my woofer too. I've been using the Bonded Logic behind the Neo10s , but want to try several layers behind and around the woofer now too. I think JohnK is going to redo his testing of the monopole, dipole and cardioid woofers and send the info to Elias to put through his wavelet app. Have you been reading that thread?

Greg


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