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CSS/XBL 1st August 2009 07:17 PM

Introducing The new CSS EL70

I'm pleased to announce the new CSS EL70 extended full range loudspeaker designed and built by Mark Fenlon of Mark Audio in Hong Kong. Over the past year or so, Mark and I spent time talking about the need for a smaller "classic" paper cone driver with extended frequency range. Both of us recognized the need for a moderately priced driver capable of providing audiophile grade output and that's easy to use in a wide variety of applications. The EL70's frequency range is ultra-wide (Fs=64Hz, Fr to 25-kHz @+80dB). Itís very capable of delivering extended low bass response and with a Qts of 0.55 is usable in many box designs. Applications range from close field desk top, small BR for power handling, larger BR for extended range, MLTL, horn etc.
The first batch is on its way from China and should arrive in Vancouver around August 17th. Prototypes and the first production units are scattered around the globe as a number of DIY people are co-operating on a variety of cabinet designs. These will be released over the next few weeks and the plan is to compile them all into one place for easy distribution.

For now there will be 3 SKUs set up on the CSS website, although others may also be developed. All drivers include mounting screws and gaskets. Here are the initial prices for the first month.

EL70 single driver US $45, C$ 50
EL70KITP1 2 drivers, 2 ports, 2 sets of binding posts, 16 gauge wire, connectors US $90, C$ 100
EL70KITP2 4 drivers, 2 ports, 2 sets of binding posts, 16 gauge wire, connectors US $170, C$ 185.

Dr Jim Griffin showed his design with 2 EL70s per cabinet at the Dayton DIY event on July 11th. He will also show these at the Atlanta DIY event August 8th. A pair of EL70s as well as a pair of Mark Audio Alpair 10s will be given away at that event.

Stay tuned, more to follow.


ejfud 1st August 2009 08:17 PM

They look like a winner.

planet10 4th August 2009 05:21 PM

I will also mention that in cooperation with Bob & Mark, a limited number of these will be treated, matched, and sold as Planet10-HiFi EL70eN.

As well, some consideration is being given to an upgrade programme for those who wish to upgrade stock drivers at a later date.

Contact me about pre-order pricing. (i'm expecting mine will start dribbling out early September)


italynstylion 4th August 2009 11:59 PM

I'm very excited to see what these can do. I'm finishing up some cabinets for these at the moment.

markaudio 5th August 2009 12:52 AM

2 Attachment(s)
Hi Guys,

I think forum members may like a little background from me on the EL70.

For some time I felt the lower cost end of the full range driver market needed drivers that could deliver greater performance. The CHR-70 was the first driver I made to meet the need for increasing performance demands of custom builders on a budget. Its giving an extended lease of DIY life to many builders. The CHR70 will continue to be available with some minor revisions coming soon.

The EL70 takes the concept further. Bob and me spent time consulting many members of this forum to gain insight. Many guys said they wanted a driver that's easy to use in a variety of box designs, have a wide range and deliver audiophile grade detail. More bass delivery was also wanted.

So, I opted to produce a range of driver models based around my 70-mm cone design. Bob encouraged me to explore paper and produce a design, thus the EL70 was born.

The EL70 is designed with a low Fo while maintaining a useful Qts above 0.5. The damping at this level means the driver will be good at handling power in smaller boxes or extended range in larger boxes. This level of flexibility was high on the "wish list" of many home builders.

Many guys complained about the lack of high range in lower cost drivers. The EL70 is the first of the 70-mm cone model drivers that works towards meeting this challenge. This driver really does help to do away with the need for a tweeter. So full range single driver purists, have fun!

I've produced a batch of EL's that will go to Dave (Planet 10) for Enabling. This holds the prospect for the supply of an up-market version of the EL70.

This gives you a snapshot of the thinking that went into the EL70 concept.

Bob will publish more data soon.



HareBrained 5th August 2009 03:43 AM

I have always loved the Vifa "classic" paper cone drivers. And I love my CHR-70's in their dual-chamber reflex box which replace my PL11-based MT. I believe these could be the "b*st*rd love child" that I've been wanting to build my first set of "epic" speakers. Now that I'm working again, I think I'll be ordering the quad-set package from CCS.

Gentlemen, fine work and I'm looking forward to published measurements and all the future impressions.

speakrsrfun 5th August 2009 02:48 PM

Damn you Bob and Mark, I already have too many projects on the go and now you throw me a tidbit like this.... Hell I may end up divorced if this crap keeps up.... Anyway with no time or extra money I'll have to live vicariously through others for the time being. Peace and keep well. :bigeyes:

Lemarchand 6th August 2009 08:44 AM

Hi guys.Do these speakers use the XBL2 technology?Are they much different than the FR125SR? Thanks in advance..

markaudio 6th August 2009 02:35 PM

Hi Lemarchand,
The EL70 is a different driver from the FR125. The cone employed on the EL70 uses a new forming process to create its profile. The cap on the EL is directly bonded to the coil former while the FR has a fixed phase plug. The FR uses XBL while the EL70 has a twin ferrite magnet arrangement with shielding.

Hi Speakrsfun,
The EL''s wont break the bank so don't worry. Enjoy the full range fun!

Hope this helps,


CSS/XBL 6th August 2009 02:58 PM


The EL70 does not use XBL though Mark and I have talked about using it on future product. The main differences with the FR125SR is the higher sensitivity of the EL which was a very specific goal. Since both use paper cones there will be similarities in the overall sound. The technology employed in forming the EL70 cone is new and bodes well for further cone development. With a slightly higher Xmax and larger voice coil the FR will handle a little more power but that is so often enclosure loading dependent.

Given the large number of enclosure designs that will be released in the next weeks it is clear that the EL parameters support a very wide range of designs. The manufacturing track record evident in all Mark Audio productions also means the driver to driver consistancy will be higher with the EL70.

We expect to be doing some extensive listening comparisons in a couple of weeks at the Vancouver Island DIY event at Dave's so look forward to those results and impressions.


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