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1000 Watt CAFz'r
Joined: Sep 2001
Posts: 1,120
A sensible, logical theory Adam. I wonder it it would work out in the real world...
Does any speaker manufacturer utilize this technique now? Also wonder has Focal tuned each speaker cone ie the Utopia line depending on weather it's a 4 or 6 and so forth...I would think the cone is physically thicker on the Utopia subs???
Does any speaker manufacturer utilize this technique now? Also wonder has Focal tuned each speaker cone ie the Utopia line depending on weather it's a 4 or 6 and so forth...I would think the cone is physically thicker on the Utopia subs???
Guest
Posts: n/a
Pioneer has used foamed polypropylene cones for the better part of a decade now. Same mass with a thicker cross section increases strength, rigidity, and internal damping with no weight penalty. And you get this technology on a pair of $99 speakers.
About the cone to surround thing - in the early 90s Pioneer had a speaker line where the cone and the surround were the same material - the two areas were just processed differently, making the cone rigid and the surround flexible. I think the foamed IMPP line replaced it though.
Who says a company has to be esoteric to be innovative [img]graemlins/thumb.gif[/img]
About the cone to surround thing - in the early 90s Pioneer had a speaker line where the cone and the surround were the same material - the two areas were just processed differently, making the cone rigid and the surround flexible. I think the foamed IMPP line replaced it though.
Who says a company has to be esoteric to be innovative [img]graemlins/thumb.gif[/img]
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Posts: n/a
Hey PEI...
You are absolutely correct that cones are flexible, but this is the point of the three cone design criteria - increase rigidity and damping while controlling mass.
I agree 100% with what you are saying in terms of the surround and spider interacting with the cone - how can it not. The surround alse radiates sound, since it moves with the driver. But, with a sufficiently damped cone, the effects of one on the other will be significantly reduced.
I have found that many companies have resorted to very light-weight surrounds and control their cone motion more with the spider, reducing the stress on 'relatively' flimsy outer edge of the cone.
I was very impressed when I toured the Focal factory with respect to how much detail they put in to every aspect of cone design and construction.
As for the tapered foam core, the Kicker SS65 and SS56 drivers use this technology. They also implement the same sort of multi-material design as Focal does, only the use a high carbon content poly front and back over the foam core.
You are absolutely correct that cones are flexible, but this is the point of the three cone design criteria - increase rigidity and damping while controlling mass.
I agree 100% with what you are saying in terms of the surround and spider interacting with the cone - how can it not. The surround alse radiates sound, since it moves with the driver. But, with a sufficiently damped cone, the effects of one on the other will be significantly reduced.
I have found that many companies have resorted to very light-weight surrounds and control their cone motion more with the spider, reducing the stress on 'relatively' flimsy outer edge of the cone.
I was very impressed when I toured the Focal factory with respect to how much detail they put in to every aspect of cone design and construction.
As for the tapered foam core, the Kicker SS65 and SS56 drivers use this technology. They also implement the same sort of multi-material design as Focal does, only the use a high carbon content poly front and back over the foam core.
Originally posted by PEI330Ci:
To date, there are very few 6” midranges that can reach above 3khz with good off axis response and low distortion. Of those, very few can accurately reproduce good dynamic response in the midbass region due the limits of their suspensions. I think it’s possible, using the varying foam core technique, to increase the upper limits of frequency response while maintaining good midbass extension.
Adam
To date, there are very few 6” midranges that can reach above 3khz with good off axis response and low distortion. Of those, very few can accurately reproduce good dynamic response in the midbass region due the limits of their suspensions. I think it’s possible, using the varying foam core technique, to increase the upper limits of frequency response while maintaining good midbass extension.
Adam
When I read that I instantly thought of the Focal Audiom 6W because what you said there, Adam, is a deadly accurate discription of that driver.
While the 6W can very accuratly produce frequencies above 3K, it's midbass extension sucks. Even Focal doesn't recomend using this driver without a midbass driver that can play some of the higher frequncies, such as the 5WS.
I have however, heard 1 driver that I thought, did a very good job of accuratly playing over 3K and also having decent midbass extension, and that driver is the 165K2.
Midbass output was,I thought, lacking yet not absent. But it was a very fast and accurate driver even above 3K. Also, like I said, the midbass was there, but output was a tad lacking.
Anyway, very well spoken paragraph Adam. I agree 100% with that.
Dave, in regards to the Polk LSi9's.
I have never really more than glanced at Polk let alone considered them a high-end speaker manufacturer although I confess I have never heard a Polk speaker before.
You said you were very happy with them considering the price. Can people expect more to come from "mainstream" audio companies? Also, what do you think so called "high-end" companies will do to make thier products even better.
Also, can CCA, look forward to an exclusive review of the LSi9's
I have never really more than glanced at Polk let alone considered them a high-end speaker manufacturer although I confess I have never heard a Polk speaker before.
You said you were very happy with them considering the price. Can people expect more to come from "mainstream" audio companies? Also, what do you think so called "high-end" companies will do to make thier products even better.
Also, can CCA, look forward to an exclusive review of the LSi9's
50 Watt CAFz'r
Joined: Oct 2003
Posts: 146
Adding too much foam will increase the cone’s mass and lower the drivers high frequency output. (causes the driver’s response to roll off earlier)
In that respect, I don't see why you just make the cone as rigid as possible without care for mass (raising the resonance frequency way past the bandwidth you want), and just push it with a LOT of power... Do we really need high efficiency? (barring use of tube amps)
There's not just the cone and surround damping to consider. There's lots of play with the cone edge and surround geometry as well.
Dustcaps also affect the rigidity of the cone, as well as changing the resonance frequencies through different boundary conditions.
[ November 28, 2004, 11:40 PM: Message edited by: hobbes26 ]
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You should listen to the LSi9s, they are very nice.
Sure, you will get more with more expensive speakers, but these suckers have an MSRP around 1500 Canadian.. Sure, that's a tough price point, but I am pleased with my purchase.
I'd class Polk as being on the edge of Mainstream with respect to their high-end products..
Sure, you will get more with more expensive speakers, but these suckers have an MSRP around 1500 Canadian.. Sure, that's a tough price point, but I am pleased with my purchase.
I'd class Polk as being on the edge of Mainstream with respect to their high-end products..
1000 Watt CAFz'r
Joined: May 2002
Posts: 1,649
Never heard the Polks, but I agree with Dave to a degree. Get a really decent set of drivers by doing your homework.
Then put the time into the install. You usually kill the guys with the high end mega buck drivers or worst case have 95% of what they have for a fraction of the price. I've seen this and judged it quite a few times now. Always brinsg a smile to my face.
Then put the time into the install. You usually kill the guys with the high end mega buck drivers or worst case have 95% of what they have for a fraction of the price. I've seen this and judged it quite a few times now. Always brinsg a smile to my face.
