Not seen one of these before, a radical new cab or not?

[warwickhunt]

Checking out eBay I stumbled upon...

[url="http://cgi.ebay.co.uk/Introducing-The-Bass-Radiator-bass-guitar-cabinet_W0QQitemZ180128918099QQihZ008QQcategoryZ4713QQrdZ1QQcmdZViewItem"]http://cgi.ebay.co.uk/Introducing-The-Bass...1QQcmdZViewItem[/url]

What is the considered opinion of our resident cab aficionados?

[Dood]

Hey John! yeh, I'd seen them a while back and really just dismissed them for their size at the time, but physically it wouldnt bother me now. I'm sure there's something to be said about the cabinet being 'round'. I suspect there would be some issue as usual, with cramming to many drivers into too small a box. I think there has been discussion about how inefficient iso-whatsis face cabinets are.. I wonder how they fair against other cabs out on the market (if they dropped the rear facing cone).

[Lfalex v1.1]

Are they actually Isobaric?, or does the rearward cone just act as an ABR?

[alexclaber]

They look like straightforward ported dipole cabs with all the pros and cons that result. The Delta 10 is a pretty disastrous bass driver, it farts out with more than about 50W in the lows despite the high thermal power handling.

Alex

[Oxblood]

I'm no cab afficionado (I leave that to Messrs Claber and FitzMaurice!), but something instinctively tells me that a cylindrical enclosure is bound to have a very strong resonance at one frequency, causing it to be something of a booming one-note samba. At the end of the day, though, in the absence of any peoperly measured frequency response charts and specs, who can tell what they'll sound like?

There's one thing: this idea is so simple that anyone could have a bash at making something similar and report back here. Then we'd know!

[alexclaber]

[quote name='Oxblood' post='18880' date='Jun 16 2007, 06:27 PM']There's one thing: this idea is so simple that anyone could have a bash at making something similar and report back here. Then we'd know![/quote]

Or if you have two matching cabs you could put them back to back.

As the lows are omnidirectional their response will be the same (i.e. still hopeless with Delta 10s) whilst the mids and highs will be combination of direct sound from the front speaker and reflected sound from the rear speaker, which will combine in mysterious ways due to phase differences.

Another way to look at it, is do you like add reverb to your bass sound? I know I don't!

Alex

[Bill Fitzmaurice]

[quote name='Oxblood' post='18880' date='Jun 16 2007, 01:27 PM']something instinctively tells me that a cylindrical enclosure is bound to have a very strong resonance at one frequency, causing it to be something of a booming one-note samba.[/quote]
The opposite is actually the case, round structures are highly non-resonant and have a far higher strength to weight ratio than flat panel structures. But aside from that all the other shortcomings of the design as pointed out by Alex et all are spot on.

[Oxblood]

That's interesting, Bill. Just goes to show how instinct can lead to the wrong conclusion. I was thinking of things like organ pipes and suchlike, but I suppose the natural resonance of a very short, very fat cylinder like this would be virtually subsonic.

[Bill Fitzmaurice]

[quote name='Oxblood' post='18912' date='Jun 16 2007, 03:24 PM']I was thinking of things like organ pipes and suchlike, but I suppose the natural resonance of a very short, very fat cylinder like this would be virtually subsonic.[/quote]
Their resonance is related to their length, not their shape, and is proportional to their length. A short pipe will have a high resonant frequency.

[Oxblood]

[quote name='Bill Fitzmaurice' post='18941' date='Jun 16 2007, 09:48 PM']Their resonance is related to their length, not their shape, and is proportional to their length. A short pipe will have a high resonant frequency.[/quote]
So I've got it completely back to front.

It's a good thing I don't design speaker cabs, innit!

[bass_ferret]

This was on bassworld - same conclusion!

[Mottlefeeder]

[quote name='Bill Fitzmaurice' post='18908' date='Jun 16 2007, 07:39 PM']The opposite is actually the case, round structures are highly non-resonant and have a far higher strength to weight ratio than flat panel structures. But aside from that all the other shortcomings of the design as pointed out by Alex et all are spot on.[/quote]
Bill, there was something doing the rounds a couple of years ago where two speakers in a tube had the cavity stuffed with wire wool. The theory was that you got more phase shift using that as wadding, so you got more phase addition, to a lower frequency, from a smaller box.

Does that ring any bells with you?

[Bill Fitzmaurice]

[quote name='Mottlefeeder' post='22970' date='Jun 25 2007, 08:38 AM']Does that ring any bells with you?[/quote]
No. I'm sure that it's just another of the thousand and one things that have been tried because it seemed like a good idea at the time. Sounds like pseudo-scientific piffel to me.

[The Funk]

What do you guys make of [url="http://www.tonetubby.com/tonetunnel.htm"]these[/url]?

[Bill Fitzmaurice]

[quote name='The Funk' post='23064' date='Jun 25 2007, 11:02 AM']What do you guys make of [url="http://www.tonetubby.com/tonetunnel.htm"]these[/url]?[/quote]
As for the drivers, there are hundreds of materials that one may use to build driver cones from, and hemp fiber is one of them. As for the cabs the same comments as above apply, though from what I see in the pictures they are, like most commercial cabs, far too small for the driver complement to operate optimally.

[The Funk]

Would you recommend something like 2 10" speakers in a cab the size of your average 4 x 10? Speaking as generally as possible, leaving aside all the other factors to consider.

[Mottlefeeder]

[quote name='The Funk' post='23132' date='Jun 25 2007, 06:01 PM']Would you recommend something like 2 10" speakers in a cab the size of your average 4 x 10? Speaking as generally as possible, leaving aside all the other factors to consider.[/quote]
If you check out the forum on Bill's web site, he has a section on graph plots for typical cabs. The message comes across very strongly that most manufacturers fill the front-face full of speakers on a box that has insufficient volume; fewer speakers in a larger (purposed designed) box will sound better.

[velvetkevorkian]

IIRC the optimum volume for a 2x10 was around the size of an average 8x10.

[Lfalex v1.1]

[quote name='velvetkevorkian' post='23292' date='Jun 25 2007, 11:17 PM']IIRC the optimum volume for a 2x10 was around the size of an average 8x10.[/quote]

For that sort of size box, you might as well go back to using horns or even transmission line enclosures.
The only reasons they're not as common as they might be are that all the woodwork/complexity make for expensive manufacturing (relative to a plain 8x10), and the fact that we've all been indoctrinated to believe that a huge complement of drivers is a good thing. Well, it looks impressive! (And I suppose it doesn't hurt power handling.)

[Bill Fitzmaurice]

[quote name='velvetkevorkian' post='23292' date='Jun 25 2007, 06:17 PM']IIRC the optimum volume for a 2x10 was around the size of an average 8x10.[/quote]
Not quite, MI drivers are optimized to operate in smaller enclosures than that. But on average the volume of the cabs they're mounted in is 1/2 to 1/3 what it should be for best results.
[quote]Well, it looks impressive! (And I suppose it doesn't hurt power handling.)[/quote]
True on both counts, but this points out the entire problem with todays bass cabs. The mold was cast 40 years ago when the average driver only handled 30 watts, and if you wanted to play loud and low you needed to use as many as could be stuffed into the box. Driver technology has made leaps and bounds in the interim, but the cabs they go into remain wallowed in the Dark Ages of audio engineering.