[navin]

Originally Posted by Bass&Trouble

There are very few co-axials that have an assembly like this, i.e. dual concentric.

Another type of coaxes, that you dont mention, and are easier to dis-assemble are the ones that have the tweeter wire running through the tweeter post, rather than being sent out through punctures in the cone. Here it would suffice to just pluck out the tweeter, or unscrew the whole post from the back, and apply a dust cap on the woofer. In my opinion, this is also the correct way to assemble coaxial speakers, although this has been met with disagreement by some earlier.

I agree B&T but one dual concentric I have had tried to mess with is the Blaupunkt BG series 4".

Those coaxials are hardly made are they? If they are these are the easiest to work with esp if the have NdFeB magnets. As easy as Pluck and Play.

BTW i'd make that a phase plug instead of a dust cap. After tinkering with some phase plugs I am sold on them. What say you?

[gunbir]

Originally Posted by navin

I agree B&T but one dual concentric I have had tried to mess with is the Blaupunkt BG series 4".

I used to have those too... though they were built well for that time, they werent worth what I paid...

there are a few coax / component convertible models out there.
I dont think dual concentric is the right term to use for this. Dual Concentric rightly refers to the way Tannoy does it.

In our range we have the aptly named Chameleons from iD that can be configured either ways.


with phase plug.


with coaxially mounted tweeter

I have seen others of late, its a trend that seems to be coming back to some extent.

[angelfire]

Well am plannin to carry it out on a JBL cs1204....What say guys??...any tips?..

[navin]

angelfire, do you have a pic?

[angelfire]

Sorry...i dont have a cam as of now to click the pic...tried gettin one fron the JBL site...hope it helps...

[Autophile]

Coaxial Speakers and Dual Concentrics are two different type of drivers.

In case of coaxial speakers the two drivers (LF/HF) are mounted on the common but the emissive point is in two different planes.

Where as in Dual Concentric (Properietary to Tannoy) the drivers are mounted in such a way (tweeter sits in the voice coil of the midbass / woofer) that emissive point shares common centres (concentric) in the same plane.

There are very few true Dual Concentric loudspeakers manufacturer one of course is Tannoy and other one is French brand PHY-Haut Parleurs. The other nearest form is used by Thiel Audio.

Dual Concentric drivers are time / phase aligned physically hence they need simple crossovers with absolutely zero correction. Generally Dual Concentric runs on 1st /2nd order crossovers.

Shown below Tannoy Prestige series Autograph Mini with Dual Concentric driver.

[hydrashok]

Forgive me if I sound stupid, but what is a phase plug? How does it make the output sound different?

I actually was under the impression that the bullet-like phase plugs on the Hertz and iD units were just a different design for dust caps.

[navin]

1. JB and Gunbir, I agree that your definition of dual concentric is correct but I think you know what B&T is talking about. So lets stick the the problem at hand (install in Opel Astra)

2. Hyrdrashok, there are NO stupid questions. A phase plug to put is simple that replaces the dust cap. shaping the phase plug (usually shaped like a short cone) seems to reduce the phase deviation esp in the upper midrange (above 500hz) of a midbass (speakers that go from about 40Hz to about 3kHz). This seems to help make teh sound more coherent. I am sure google can help you with a clearer and more detailed defintiion.

3. Anglefire. that coxial seems to be very simialr to the Blaupunkt I was not successful with. I would leave the tweeter there (disconnect the wires) and add a small tweeter in the rear mirror pods.

If you are feeling adventourous try to see if you can pry the tweeter assembly loose. If you can you can replace the assembly with a home made phase plug or dust cap. you will need a small light plastic cup (about 1" dia) for each speaker to do this. I used to use the canisters Leggo Stockings came in.

[hrag]

Originally Posted by harmon_bro

I bought an Alpine 9856, and yet to decide on the speakers.

I did a search but didn't find anything. Can someone please point me to an authorised dealer for Alpine HUs in Chennai? Thanks in advance.

[navin]

Originally Posted by Autophile

There are very few true Dual Concentric loudspeakers manufacturer one of course is Tannoy and other one is French brand PHY-Haut Parleurs. The other nearest form is used by Thiel Audio.

Dual Concentric drivers are time / phase aligned physically hence they need simple crossovers with absolutely zero correction. Generally Dual Concentric runs on 1st /2nd order crossovers.

and...
1. KEF also uses this in their IQ series.
2. Not all dual concentric drivers are phase aligned (in theory theya re supposed to be) but often they are not proerly degined.
3. In a few cases the cone acts as some sort of wave guide.

[Bass&Trouble]

Originally Posted by navin

As easy as Pluck and Play

Originally Posted by navin

Those coaxials are hardly made are they? If they are these are the easiest to work with esp if the have NdFeB magnets. .

By those, do you mean the ones that are made without punctures in the cone? Yes they are. Many manufacturers make them, and while some would reserve them for their higher end lines, others would maintain this construction even for their entry level lines. A good example of the latter is MB Quart. Even their 6x9 uses this method. In a 6x9, it is difficult to take the tinsel leads all the way to the cone neck from the binding posts because the tinsel leads have to run parallel to the 9" side. Hence, such a long tinsel lead can cause flapping against the cone/ spider. I am in support of not pucturing the cone in any part of it's radiating surface whether it is a coaxial or just a woofer.

MB Quart Coaxial 6x9:



Regular Coaxial:

Originally Posted by navin

BTW i'd make that a phase plug instead of a dust cap. After tinkering with some phase plugs I am sold on them. What say you?

In good drivers, carefully designed phase plugs sound good. I have even liked certain drivers which have phase plug-shaped dust caps rather than the pole-piece mounted, solid phase plugs. But as you would agree, the first part is to get the driver right. I mean, even without a phase plug, what fault can I find with a Scanspeak Revelator?

[navin]

Originally Posted by Bass&Trouble

I mean, even without a phase plug, what fault can I find with a Scanspeak Revelator?

It's Price! :-)

BTW do oyu mean to say that the SS Revelators have phase plugs now?

[Samurai]

Originally Posted by Sam Kapasi

Here's the picture Navin sent me. Who is this guy? I want to hug him. Talk about an enthusiastic customer

Other JBL customers may want to beat him up for stealing their stickers...

[Bass&Trouble]

Originally Posted by navin

BTW do oyu mean to say that the SS Revelators have phase plugs now?

Lol, no!

Just meant that it isn't always necessary.

[Autophile]

Originally Posted by navin

1. KEF also uses this in their IQ series.
2. Not all dual concentric drivers are phase aligned (in theory theya re supposed to be) but often they are not proerly degined.

KEF Uni-Q drivers does not resemble to Dual Concentric design its more of a coaxial. And Dual Concentric is a trade mark of Tannoy's properietory driver technology, not a generic category of transducers.

More over Tannoy Dual Concentrics are phase/time aligned.