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Old 25th September 2014, 09:04 PM   #1
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Default CHN-70 breaking in

Recently received a pair of the new Mark Audio CHN-70 drivers. Eager to get my ears on them and short on time to build a new enclosure, I ran a quick sim of the CHN-70 in a Metronome designed for the FE108eSigma. Not half bad! Just stuffed BlueTack into the old screw holes, and Voila!

So they are now softly playing classical music curtesy of WMHT. Sounds nice so far, but with peek levels of 60 dB at 1 meter, who can tell for sure? We shall see what they sound like in a few weeks when it’s OK to play music at reasonable listening levels.

The CHN-70 is the blue driver, sitting between the F120A Met (right) and FF225wk Pappa’s TL (left).

Cheers, Jim
Attached Images
File Type: jpg CHN-70 Met SPL.jpg (50.9 KB, 537 views)
File Type: jpg CHN-Met-s.jpg (53.0 KB, 528 views)
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Old 26th September 2014, 06:35 PM   #2
mikje is offline mikje  United States
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I put a pair in a small vented box on Monday, so I've got the first 100 hours on them. I'll give them a little more juice today. So far, I like what I've heard. After another 100 hours or so, I'll give them even more juice. When Dave from Planet 10 and the other gurus on these drivers and enclosures have more designs, I'll either put these in something else or order another pair. These seem like great little speakers, especially for the price.
Mike
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Old 4th October 2014, 02:30 PM   #3
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Early listening impressions of the CHN-70 in the Metronome (as shown above) after 90 hrs of break-in—can’t wait any longer. NOTE: Further break-in may result in improvements! It takes much longer to break-in the MA drivers following Mark’s guidelines— only able to do 10 to 12 hrs per day (in two stretches), as opposed to my practice with Fostex drivers, where I run them 24/7 until I get to 300 hrs or so.

Playing with peak levels reaching 70 dB— higher levels will come later after I get more hrs on the drivers. Pretty obvious at this stage that the some BSC is needed: tried 0.5 mH & 1.5 ohms, but moved up to 0.5 mH & 3 ohms.

Source was my 15 yr old Denon CD player; driven by my vintage Yamaha CR-1000 receiver (direct coupled SS).

Test tracks:
— Ode to a Butterfly, performed by Nickel Creek
— Urgent Desir, performed by Lara Fabian
— Crazy Faith; performed by Alison Krauss
— Blue Rondo a la Turk, performed by Dave Brubeck
— Nevermind; performed by Airto Moreira

Comparing with FE108eSigma Mets; note that the CHN-70 cost $27 each, while the 108 cost $112.50 each. My wife & I agree that the CHN-70 sounds quite good; we would be happy listening to them for long periods of time. No issues with sibilance; no harshness. Because I have a particular fondness for the 108, I may suffer from expectation bias; my wife is a disinterested party and only knew that I was switching between speaker A and speaker B. In my wife’s words: the CHN-70 sounds more smoothed over; piano notes are not as clear & bright; cymbals are also a bit dull by comparison to the 108. The 108 also has a bit more depth of sound stage than the CHN-70. Other differences are even more subtle; suffice it to say that the two drivers do sound different in the mid-range, but I think it’s a matter of preference rather than one being more correct than the other. And with sub-par recordings, the CHN-70 may help conceal warts that would otherwise make the recording unlistenable for some. I think in particular of classical recordings where the massed violins are particularly harsh. (Which begs the question: is it better to use fewer mics, further from the instruments so that the sound from individual stringed instruments have time to blend, as they would in a live concert; or place many, many mics close to the strings and assume that the blending at the recording console approximates what you hear live in your favorite concert hall seat? Inquiring minds want to know!))

As with the 108, I would use the CHN-70 with a sub. The bottom end may be sufficient for casual listening, but adding another octave on the low end takes it up to another level.

Since they aren’t fully broken in yet, I can’t crack up the volume to see how they do at louder levels, but I am expecting them to do well there too.

Bottom line: I think the CHN-70 is already looking like a real bargain! (However, for those who have wondered: yes, there _is_ a reason why Mark produces the more expensive Alpair 7 series drivers.) When they have a few hundred more hours on them, they may be even better!

More later…

Cheers, Jim
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Old 7th October 2014, 05:07 PM   #4
Bare is offline Bare  Canada
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Seems a bit odd imo, the notion of break in as per the requirements of an Octogenarian Triumph Spitfire engine.
Ie; gradually and incremental usage for wayyy too many miles as the tedious break in procedure advances.
There are not 2000 poorly matched machined parts all rubbing together in a speaker.
The Spider is the item in a speaker that benefits from a bit of use softening.
Unlikely you are doing the things (or yourself) any favors babying/protracting the procedure.
But then these are yours :-)
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Old 7th October 2014, 05:26 PM   #5
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Bare,

I'm trying to follow Mark's guidelines. He designed & built them, so he should know!

And I have read the laments of those who flogged their MA drivers too hard & too soon...

Cheers, Jim
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Old 7th October 2014, 09:21 PM   #6
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Interesting stuff as always Jim. Thanks for sharing; I've had very little experience with the CHN (a few minutes with them in a test box only) so good to get some other views. As for break in, +1 in following the manufacturer guidelines. Since they designed & made them, methinks they might know what the optimal means is...
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Old 7th October 2014, 09:34 PM   #7
Bigun is offline Bigun  Canada
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Just an opinion only - The manufacturer is also wanting to avoid unnecessary warranty returns or to have to provide more detailed instructions and support for more complex break-in procedures. I doubt very much that the loooong break-in regime is the only way to reach the goal but it would likely be a nightmare to expect customers to follow something more complex (e.g. using pink noise at escalating and de-escalating peak values).
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Old 7th October 2014, 09:54 PM   #8
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I believe Mark has specifically warned again using pink noise, as well as music with heavy bass and drum thumps. Somewhere Mark has a thread where he talks about the suspension/spider and why he recommends this gentle break in.

Cheers, Jim
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Old 7th October 2014, 10:03 PM   #9
chrisb is offline chrisb  Canada
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Yes, the legions of those who profess to know more about driver design in general, and Mark's specifically, must cause him a mixture of bemusement and frustration - weighted more towards the latter, I'd be thinking .

What harm can it do to follow the manufacturer's recommended procedures?
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Old 8th October 2014, 01:55 AM   #10
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Quote:
Originally Posted by Jim Shearer View Post
I believe Mark has specifically warned again using pink noise, as well as music with heavy bass and drum thumps. Somewhere Mark has a thread where he talks about the suspension/spider and why he recommends this gentle break in.

Cheers, Jim
Jim:
Thanks Jim to taking time to make this thread to pass on your project knowledge and future results and for operating the drivers correctly.

Bare:
I've spent the last decade researching, designing and building long-throw, low-mass and ultra low-mass extended response drivers. Their design and operational requirements are Significantly different from standard designs. The power-train of a Markaudio driver consists of a small number of components but the design and operational properties remain extremely complex. I've published a number of posts on these specifics over recent years that explain issues to do with the working loads on suspensions and the operational properties of low-mass wide-profile cones.

Bigun:
Naturally you're welcome to your opinion. However, its not accurate. Let me be ultra clear on the issue; I approach my work from a "mechanical engineering" perspective. So when I advise an operational procedure, its done purely in the interest of giving end-users the best opportunity to get the most from their Markaudio drivers and enjoy them. Nothing else is in my mind when I'm doing this work.

Guys:
Members and end-users......Anybody! Please bear in mind that when you're using an low/ultra-low mass full-ranger, especially a long throw unit (extend excursion) they're NOT the same as your typical parts-bin specials that constitute the bulk of choice on the market today. The bulk makers do 2 main things:

1 - They produce more mechanically limited units with relatively stiff suspensions. Why: because they're cheaper to make, use lower grade materials, easier to assemble requiring less jig/alignment and the reject rate (NG rate) is lower.

2 - They produce drivers that have a wider power-band margin because they consider most operators (you) to have inadequate knowledge on driver loadings and operation. Suspensions, coil bodies and cones are beefed up. Cones emissions are particularly damped in favour of increased mass to handle unforeseen or over-extended loadings.

These common types of driver won't normally require much (if any) running-in.

While I can't speak for other makers, I strongly recommend paying attention to any advisories they issue and operate the drivers accordingly.

If you're a regular user of proper authentic full-range units, you'll know what I'm talking about. If you're relatively new to authentic full-range technology, please take note and don't fall into the trap that an increasing number of members make; Assuming that full-rangers are essentially the same as other drivers, They aren't.

Thanks
Mark.

Last edited by markaudio; 8th October 2014 at 02:00 AM. Reason: typo fixes
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