Markbass piezo clipping

[bass4u]

Just recently the piezo tweeter in my Markbass CMP121p has started to clip when playing with a lot of attack. All the eq controls are straight up and the VLE and VLF are turned all the way down, the blue input light never comes on and the maximum volume the amp has ever seen is not quite halfway. IMO the piezos in the Markbass cabinets are less than stellar. The piezo in my NYC121 cabinet has already blown and I had the cabinet replaced while it was still under warranty. The NYC121 I now run with the tweeter control turned very far down and it is working out ok. Sure wish Markbass had installed a tweeter control on the CMP 121p. I don't like using the VLE because I think it robs the cabinets of definition. If I use just the NYC 121 and unplug the speaker to the CMP121p the sound is really good. I was thinking of using an alternate(better grade) piezo in the CMP121p but the piezo is an odd shape and I think would be hard to find. I would really like to somehow add the tweeter control like is in the NYC121 cabinet to the CMP121p. Anyone have any ideas that could help me out? I'm almost ready to just disconnect the piezo in the CMP121p but I've heard what it sounds like without a piezo and it sounds pretty dull. Is there an internal crossover in the CMP121p that doesn't allow certain upper range frequencies to the 12" speaker? If so do you think just bypassing the cross over would make the 12" speaker have a little more high end? Any help or opinions greatly appreciated.

[JimmyM]

don't know what to tell you about installing a tweeter control or getting a new tweeter (probably going to be your only choice), but i can tell you for sure that running the 12" by itself out of the crossover does nothing.

[bass4u]

Originally Posted by JimmyM

i can tell you for sure that running the 12" by itself out of the crossover does nothing.

Do you mean by nothing, that it will not damage the headunit?

[JimmyM]

Originally Posted by bass4u

Do you mean by nothing, that it will not damage the headunit?

it won't damage the head (although markbass says this'll void the warranty...for what reason i don't know because piezos have nominal impedance and don't really change the overall impedance of the cab). but you won't notice a tonal difference with the 12" in or out of the crossover. honestly, i think they tell you that it'll void the warranty because they don't want you to hear the frequency hole between the 12" and the piezo. it's a killer sounding little cab, but i believe there is a hole between the two.

[bass4u]

I agree completely with you on that. When the piezo blew on my NYC121, the cabinet sounded lifeless. Good solid low end but no definition unless you eq'd the amp drastically.

[billfitzmaurice]

Originally Posted by JimmyM

don't know what to tell you about installing a tweeter control or getting a new tweeter (probably going to be your only choice), but i can tell you for sure that running the 12" by itself out of the crossover does nothing.

+1. Piezos and twelves don't share any range; for that matter there's a major response hole between where the twelve leaves off and the piezo kicks in.
Most piezos cannot handle more than 25 volts or so; that's only 100 watts paired with an 8 ohm woofer. They really should be used in pairs, series wired. The resulting 50 volt limit allows them to handle the equivalent of 400 watts.