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-   -   Next Gen 70-mm Markaudio paper cone (http://www.diyaudio.com/forums/markaudio/181739-next-gen-70-mm-markaudio-paper-cone.html)

markaudio 24th January 2011 07:07 AM

Next Gen 70-mm Markaudio paper cone
 
2 Attachment(s)
Hello Chaps,
Take a look at these 2 pics and you'll see I've been busy brewing a new 70-mm paper cone. Still early stages but we've so far managed to reduce the neck density from previous models while maintaining stability under initial test loading. I've also had to coat the neck with a fine polymer coating. This is a hand sample. If successful, we'll apply by machine.

As you see, its a follow on from the Alp 6P. The fibre weave is less dense and we've changed the binding agent to maintain rigidity. You may also notice a "press point" pattern on the underside of the cone, again to aid stability.

At this time, we've got the front of the power train (cone, surround and cap) to come in at 3.35g, (0.7g lighter than current CHP-70). That's ubber light so will have to run some prototypes and see if we can maintain stability under running and shock loads.

One thing's for sure, I'll have to match it with a ubber light coil to keep tipping weight off the back of the cone. With soft complaint long travel suspensions, this ones going to "tweak" me engineering and production skills a bit more.

Ummmmmmmph....... interesting next few weeks me thinks.

Cheers

Mark.

Scottmoose 24th January 2011 10:15 AM

Very nice. :) If you can get this out as, say, a Gen.2 CHP, it'd make a good partner for the CHR and together they'd cover a wide range of potential users. Out of interest, assuming equivalent motor power to the CHR, I imagine the efficiency will be up slightly with the lighter powertrain?

Completely beside the point, but I really like the frame colour too (deliberate, or is that just the natural shade of the poymers? Either way, it matches the cone very well). Might be worth keeping it that shade. Or am I the only one who likes that?

aptquark 24th January 2011 10:19 AM

hmm...Mark I can't see those that well...can you send me 4 of those for a more close up (in a box) visual inspection??

I promise not to ship them back.

antronx 24th January 2011 11:24 AM

Hi Mark. I looked at product listing at your site, you got some fine speaker drivers there. I am curious about off-axis frequency response performance, especially in high frequency range. I have a pair of 4" Tang Band full range drivers, but their HF projection angle is very narrow, prompting me to look into adding a tweeter.

markaudio 24th January 2011 01:51 PM

Quote:

Originally Posted by antronx (Post 2444315)
Hi Mark. I looked at product listing at your site, you got some fine speaker drivers there. I am curious about off-axis frequency response performance, especially in high frequency range. I have a pair of 4" Tang Band full range drivers, but their HF projection angle is very narrow, prompting me to look into adding a tweeter.

Hi Antronx,
Many thanks for your support. An interesting observation. Please take a look at graphs (Figs. 10, 11 and 12) from a PDF on this link:

http://www.markaudio.com/sites/all/f...-12-review.pdf

You'll notice that in Fig 11 (Alpair 12) has rising HF responses from on-axis to 30 degrees off-axis while the other drivers have falling off-axis HF responses. This data is from an independent comparative test and review of 3 full-range drivers including the Alpair 12. Along with the Alpair 7, the Alp12 is the first Gen. 2 driver to use my Multi-form cone technology. This production method allows for a more "open" or "shallow" cone profile that produces a wide dispersion pattern. Along with the rising mid-high response feature, the Gen. 2 drivers offer a useful off axis delivery.

I'm hoping as business grows, I'll have the funds to spend on more anechoic testing, to include up-dating future data sets. In the meantime, this Japanese test review is a good performance indicator for all models using Multi-form cone technology. The current Multi-form coned models are:

Alpair 6P and 6M
Alpair 7
Alpair 10.2
Alpair 12
CHR-70 (Gen 2)
CHP-70 (Gen 1) Japan
CHP-70 (Gen 1) Germany
EL-70 (CSS Canada)
BB4-AL (Omnes Germany)
4 X 72-mm cone type 1 OEM commercial variant model drivers
2 X 74-mm cone type 2 OEM commercial variant model drivers

Here's a buying tip: When looking at Full Range drivers and you want higher HF and wide dispersion output, check how deep the cone runs from its outer edge to inside the cone neck. If the cone is relatively deep and has a large phase plug or whizzer, there's a good chance its HF wide dispersion pattern will be limited. Such cone designs effectively act like funnels, great in your in the sightline of prime emittance (on axis) but not so good once off the prime sightline (off axis). If the cone is shallow (from edge to neck), has a small-short phase plug and/or shallow whizzer, or better still having no plug or whiz, its likely to have more HF wide dispersion. Hope this helps.

Cheers

Mark.

antronx 25th January 2011 03:21 PM

Thanks for the info. When I am ready to upgrade to better full range drivers, I will consider your offering.

Mr.Mantas 27th January 2011 11:14 AM

I love the white body color! Looks stylish :)
Mark is there any possibility to make the surround color other than black?

buzzforb 27th January 2011 03:02 PM

How is the HF dispersion on the 10.2 compare to the A7 or A12. I just purchased a pair today to use in a FAST system. until getting that worked out, I will be using them in the Pensil design.

markaudio 28th January 2011 12:41 AM

Quote:

Originally Posted by buzzforb (Post 2448122)
How is the HF dispersion on the 10.2 compare to the A7 or A12. I just purchased a pair today to use in a FAST system. until getting that worked out, I will be using them in the Pensil design.

Hi Buzz,
The new 10.2 cones are a more shallow and wide profile design compared to the Gen. 1 Alp10. So the on/off-axis response is very usable. All the Multi-Form cone designs have a "wide mid-HF" feature.

The Alp10.2 are in effect a larger version of the 6M/6P and 7 so the cone characteristics are on the larger scale.

Cheers

Mark.

Scottmoose 29th January 2011 09:18 AM

Perhaps it would be worth moving the OT queries / those unrelated to the new CHP to a different thread, or merge them into existing threads dealing with those topics? Seems a shame that only about 50% of the posts thus far have actually been on the topic of the projected new CHP.


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