Marc.O plans on Hornplans site are free for DIY use, not commercial use. But, all
Marc.O plans are property of « Marc.O Hornplans® » and under copyrights, subjects
to intellectual property international laws. So don't buy cabs which are manufactured
by unauthorized dealer. Only two dealers are authorized and they are in France.
- Fertin Son & Lights
- Menuiserie Christophe Mulot (Asher)
So any of others companies are unauthorized dealers. If you buy from them, you are
exposed to international laws. This is called counterfeit !
Companies that make copies of Marc.O plans make it for easy money:
- They aren't capable to design valid cabs
- they save money of R&D
- you don't know how they build cabs and if they respect basic rules of building
- you don't know if they use the right loudspeaker
- you don't know if the design will sound good
- no engineering = no support
In recent months, I was warned by some people that a few companies sell cabs from
my plans. As for exemple, an Hungarian compagny called Cronos Acoustic sell a cab
called IMPULSE 21 which seems in many points copy of MTH-4654.
I have sent them an email, and Cronos Acoustic reply me that it was a different design.
But problem, dimensions are the same, and the brace in horn is the same shape as
MTH-4654. Cronos Acoustic doesn't give any technical explanation to justify that,
doesn't give any argument, no technical drawing, no images of the construction, no
sim of Impulse 21, nothing. Cronos Acoustic just reply that they invite me to dinner
and verify the design after dinner !
So I think Cronos Acoustic takes me for an idiot (4000 kilometers round trip for
So judge by yourself, at left MTH-4654, Cronos Acoustic Impulse 21 at Right
I will add that a design like Cronos Acoustic Impulse 21 with 105dB 1w/1m and 34Hz
-3dB (Impulse 21) within these dimensions is impossible: It's a lie !
Take care of not buying counterfeit or cabinets that don't respect copyrights laws.
Companies that do counterfeit are parasites of society. They not encourage people
offering free DIY plans to publish news plans. They kill creation and DIY !
I registered "Marc.O Hornplans®" as a trademark to combat counterfeit. It will not
stop all counterfeit, but it will add a step more against.
Original documentation of Cronos Acoustic Impulse 21 viewable below