What is the science behind this?

[graaf]

just read the thread!

 

[Cal Weldon]

Thank you for your comments Earl.

If a single box is all you have

Single divided box, two amps and a ported woofer on the bottom. All the wiring is internal in case you were wondering. I am rather pleased with it. It's my second attempt at an all in one.

 

[Cal Weldon]

Interesting sense of imaging? Good or Bad?

Not sure, I kinda like the sound when I am a little off centre. It matches my personality

 

[joe58]

Cal: Well I'll give a version ago of my own in the summer with 60 degree sides, but with some B3N's and some other Hivi tweeters I have lying around. One last thing, just wondering what woofer is that one the bottom?

 

[phase_accurate]

And then there are other designs that do the contrary (i.e. widely separated "tweeters") - also because of good imaging ....

Celtic Cabar - Celtic Audio Ltd.

To be honest, it is targeting another application of course. While the geneva is for casual listening - the Cabar is made for studio monitoring purposes.

Regards

Charles

 

[joe58]

What drivers is the Celtic using? Just out of interest is there hidden LF drivers in the ends of the tubes behind the two smaller drivers?

 

[phase_accurate]

You can see a close-up picture of one end on one of John Watkinson's books:

http://www.superbookshop.net/covers/120/9780240515120.jpg

The woofers are hidden behind the metal grill that looks a little like a golden stripe around the tube (i.e. between the celtic logo and the mid-high driver). They each use a part of the tube as closed box. The rest is for the electronics.

Don't know what driver the Cabar uses but I have asked Jowhn W. about the driver used on a newer flat speaker (meant for wall placement). To be more exact I asked him whether this was a Jordan driver and he said that it was a proprietary one and that the only thing it had in common with a Jordan driver was the manufacturer of the rubber surround.....

AFAIK the Cabar has widerange drivers on the backside as well. The whole araangement is steered by its active crossover in such a way that it acts as an omnidirectional source at low frequencies and then merging to cardioid with rising frequency.

Regards

Charles

 

[joe58]

Sounds interesting, I couldn't see two very small drivers hitting the 30hz it mentions on the site. Needs more info and pics on the design to demonstrate why it's different, as a casual look just shows to small drivers and not what it really is. Just a thought.

 

[Don Hills]

The science behind the design of the system in the opening post is possibly that described in this paper:

http://www.embracingsound.com/docs/SingleBipolarLoudspeakersystemforstereoreproductionb0.91.pdf

Check out Figure 15 and compare it to the picture in post #1.

 

[Wavebourn]

Here is my version: stereo bass guitar rig. Central console of folded horn with mid-high freq drivers.

 

[Cal Weldon]

just wondering what woofer is that one the bottom?

Umm, uhh...not sure actually. It's an 6.5" OEM out of a umm, uhh, well I can't remember. Samsung maybe? When I pull stuff like that I just measure the volume and the port size for when I end up using it. That determined the height of the Pentagon.

 

[phase_accurate]

Here is my version: stereo bass guitar rig. Central console of folded horn with mid-high freq drivers.

Nice and compact build ! But does it go low enough for a bass ?

Regards

Charles

 

[joe58]

Cal: Oh right ok, I was thinking of using a 6.5er Tangbang mini subwoofer, but running some Winisd and then a sketch up model shows something a little bigger than I would have like.

Like Phase_accurate asks; how low does it go?

 

[Cal Weldon]

Are you speaking of the W1139? I found it works well in a 0.7 ft^3 and a passive radiator.

 

[joe58]

Yeah I am, I was hoping to make the dock to a reasonable size(would be having to make compromises). Winisd was giving me 11 litres and that looks a tad big, but I may be able to compromise on the LF's and size that down a little as I wanted it to be roughly the size of a Geneva Medium( 36.6 cm x 19.7 cm x 25 cm (14.4" x 7.8" x 9.8")) but I may be pushing my luck here.

What can it do in that enclosure, ie can it actually be classed as a subwoofer like a good 10inch and produce the base?

 

[Cal Weldon]

I have a slightly different take the term subwoofer. When I was cutting my teeth, a subwoofer had an Fs of 20Hz or below. It was able to produce infrasonic frequencies, that was the 'sub' part how ever incorrect that might have been. Nowadays it seems that any long throw woofer is called a sub.

I am using it up to 100 Hz where the midbass on the front takes over. I would suggest with the passive radiator I am achieving in the neighbourhood of 40 Hz, possibly lower. The system is as bassy as you want it with the plate amp.

 

[Wavebourn]

Nice and compact build ! But does it go low enough for a bass ?

Yes, for 4-string bass. Meaty, punchy. For 5-string bass something bigger is needed.