[navin]

Originally Posted by DocG

However a question related to what you've said above:
What difference does it make? Does this design improve efficiency? Accuracy of the woofer? or is it just design variation?
The reason I ask this is that many other manufacturers of say more expensive equipment still keep their magnets behind the cone, does that mean that this new design has flaws in high power/flex (Xmax) applications?

DocZG, please do not embarrass me with statements like "God of BOOM". there are many on the forum who know much more but are less active (Sam Kapasi, B&T, Gunbir, LBM, Autophile, etc...).

Every speaker (driver) is a set of compormises. Today with the ammount of computer power at our disposal a speaker can be made to suit just about any set of parameters if certain tradeoffs are accepted.

Modern materials do not guarantee good speaker design. Common sense and comphrehensive knowledge of the practical limitations of the laws of physics (and material sciences) is more important.

One of my pet peeves (for many many years - ever since the chinese comoditised the manufacture of SmCo and NdFeB magnets) is why every speaker does not incroporate such a magnet. Woofers and midranges could benefit as such a small magnet could well be engineered to fit inside their phase plugs or to shaped to act like one.

As long as the magnet can produce an adequate flux field it does not matter if the magnet is made of ferrite or rare earth. Neither does the location of the magnet infringe on a woofer's Xmax. Ferrite magnets are still just much cheaper than a similar NdFeB magnet although the price difference has dropped dramatically in recent times (say since '95). Almost all permanant magnets (ferrite and rare earth) are made in China (In India Morris Electronics, Aagrola, PML, etc.. have virtually shut shop). AlNiCo enjoys a niche market however.

As far as your question on Xmax goes. In general I have not been too happy with the performance of large Xmax woofers. Most of them have a huge Mms which is required to keep the Fs reasonable. However this huge MMs seriosuly affects their sensitivity. If BL was to be pushed up to improve this, the motor would then have to be upgraded to compensate for the higher Bl and the whole vicious cycle would start again.

The best way to choose a woofer is to first understand what the cabin's / room's low frequency (sub 200Hz) transfer function is. To some degree this can be modified but the results of these modifications are not always WAF-compatible.

Once one has a handle of the transfer function (usually room gain) one knows what roll off one needs to end up with a reasonably flat response. Then choose the roll off and F3/F10 of the woofer to match.

An alternate way is to go bipole (a la Sigfried Linkwitz and company) but this requires larger (high Qts) woofers to produce the same SPLs as smaller woofers in monopole. This has it's own set of compromisies.

[Flying Bong]

Originally Posted by navin

An alternate way is to go bipole (a la Sigfried Linkwitz and company) but this requires larger (high Qts) woofers to produce the same SPLs as smaller woofers in monopole. This has it's own set of compromisies.

Yep needs EQ to compensate for rolloff at bottom end....

[frankmehta]

Oh absolutely Flying Bong. I do feel sometimes that my Luccent sub doesn't go really low. Bottoms out slightly earlier than my Ground Zero sub. The very low frequencies are not played with that much authority. What kind of eq are we talking about here?

[Flying Bong]

Originally Posted by frankmehta

Oh absolutely Flying Bong. I do feel sometimes that my Luccent sub doesn't go really low. Bottoms out slightly earlier than my Ground Zero sub. The very low frequencies are not played with that much authority. What kind of eq are we talking about here?

Well I was specifically referring to dipole/open baffle midbass/sub applications for home audio, as was Navin I think. In case of an open baffle/dipole, since the sound emerging from the rear of the speaker baffle is out of phase with the direct sound from the woofer, there is some cancellation of output which is greater in the lower frequencies. In fact the output of a dipole drops off at 6db/octave below a frequency related to baffle width....Navin would know the exact formula . EQ is required to compensate for this rolloff, that all I know

Honestly, I dont know about what kind off EQ would help your Luccents go as low as your GZ sub. But Navin's point about selecting woofers based on room gain is extremely valid for car audio where cabin gain can be significant for low frequencies. Basically if there is a lot of cabin gain in your car, it should compensate for an earlier rolloff in your sub's low end response. Rest gurus will elaborate!

Of course, I have only read about this. I have not verified this empirically in my own car using RTA or anything but would like to if time and availability of measuring equipment permit.

Sorry Frank, in summary my comments have been all OT, apologies for hijacking your thread - looking forward to the final install pics - Luccent subs look very interesting.

[frankmehta]

that was some nice knowledge :-) it's not what we would call hijacking. its called enlightening.
Thanks for that gyan. can one elaborate on cabin gain with respect to car acoustics?

[Bass&Trouble]

Originally Posted by frankmehta

I do feel sometimes that my Luccent sub doesn't go really low. Bottoms out slightly earlier than my Ground Zero sub. The very low frequencies are not played with that much authority. What kind of eq are we talking about here?

Amey has fallen in love with the Lucent sub recently, and is constantly nagging me to get him one. Which I can't. I suggest you guys swap subs and all 3 of us can be happy.

[frankmehta]

i love my luccents. amey can buy the other lucent.
i.e.: A reputed audio manufacturer in India, with technology from Germany, and research houses in America, and 'production houses' in Dharavi. Yes, you guessed it right: Dhoom Audio has their own lucent range. In fact, their website has gone into 'construction' mode, a la Illusion Audio :-)
Looks like they are introducing the 'Farbon Series' of speakers. Waiting with bated breath and half eaten fingernails!

[jkdas]

Originally Posted by frankmehta

i love my luccents. amey can buy the other lucent.
i.e.: A reputed audio manufacturer in India, with technology from Germany, and research houses in America, and 'production houses' in Dharavi. Yes, you guessed it right: Dhoom Audio has their own lucent range. In fact, their website has gone into 'construction' mode, a la Illusion Audio :-)
Looks like they are introducing the 'Farbon Series' of speakers. Waiting with bated breath and half eaten fingernails!

So are many others
http://www.team-bhp.com/forum/produc...they-made.html

[frankmehta]

ive seen this thread before JK. what do you imply by this?
doesnt the fact that we all are persisting with our illusion speakers and asking for more and more, cement the fact that we love them, regardless of how or where they are made?
besides, almost all the popular brands we all buy have their production houses in China. Does it make them a lesser product?

[karankapoor]

does that makes a difference where are they made.

now a days many companies are getting there products maid in china for cost cutting purpose.

[jkdas]

Originally Posted by frankmehta

ive seen this thread before JK. what do you imply by this?
doesnt the fact that we all are persisting with our illusion speakers and asking for more and more, cement the fact that we love them, regardless of how or where they are made?
besides, almost all the popular brands we all buy have their production houses in China. Does it make them a lesser product?

Just that the new comers may have the know-how and stuff like others. Down the years maybe they too might get better as they are still a start up. People can always buy other firms/ out source stuff.

And on a minor note; cant one sue Dhoom?

[frankmehta]

I doubt anyone would bother about a company like Dhoom eating into their profits. LOL.
Dhoom comprises of say, 1 out of 200000 audio systems sold in India. This is just an assumption. I would not say Dhoom is a CRAP brand (even though I am tempted to,) but I would hate it if a company made speakers that sound worse than OE and then rant about their international standards, and how they are the best in their segment. Yes, dhoom might sound better than Hollywood Audio and Fusion audio and the latest entrant Autobahn, but calling themselves leaders in car audio since 200x is pushing it!

[frankmehta]

How much does Polyfill in the sub enclosure help? I am right now at the crossroads of modifying my sub enclosure (increasing its volume) to accomodate my 2 subs.
If the enclosure volume is say, 1.5 cu ft, how much polyfill can be added, to make the enclosure 'seem' larger to the subwoofer?
Lets frame that again: How much polyfill can one load in an enclosure? After a point, the sub will 'know' that the enclosure is small. What is that limit?

[Invinsible]

Originally Posted by frankmehta

How much does Polyfill in the sub enclosure help? I am right now at the crossroads of modifying my sub enclosure (increasing its volume) to accomodate my 2 subs.
If the enclosure volume is say, 1.5 cu ft, how much polyfill can be added, to make the enclosure 'seem' larger to the subwoofer?
Lets frame that again: How much polyfill can one load in an enclosure? After a point, the sub will 'know' that the enclosure is small. What is that limit?

I suppose this might help you.
Sub Box Polyester Fiberfill

Usually polyfill works best if you going for a smaller enclosure than normal requirement so that it makes the sub act as if it's a normal large enclosure.
Any idea as to what is the normal enclosure size required for luccent subs?
I suppose also helps in cutting the resonance created inside the box.

[frankmehta]

thanks abhishek. i kind of had this in mind, but now i am making a new larger enclosure altogether. so might not need it. unless it has a large influence on the quality
any 'side effects' of adding polyfill??