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taming the piezoelectric [message #43880] Sun, 08 February 2004 21:39 Go to next message
wasteh202 is currently offline  wasteh202
Messages: 137
Registered: May 2009
Master
I have a pair of the 2Pi towers. I like allot of things about this speaker. It is a great value for the money, and give a terrific range of music without comprimise by an XO, the bass is strong and low.
But, my one complaint is the piezoelectric by Motorola is too fatiging for my ears. I would rather not use tone control or an equalizer in the chain to augment the sound. Is there any way that I can tame this horn some that will take some of the edge off ? I have read about some tweaks to the KSN1038.. but can not seem to find what I am looking for.
I have other speakers (planar and box) that I can listen at the same or louder decibels without fatigue, but this speaker will not allow me to listen at high volumes without turning down the music after a short time.
I would really like to keep them, but if I do not arrive at a solution to this problem they may go up for sale.

Anybody ? .... thanks.

Re: taming the piezoelectric [message #43881 is a reply to message #43880] Mon, 09 February 2004 00:28 Go to previous messageGo to next message
gumby1 is currently offline  gumby1
Messages: 63
Registered: May 2009
Viscount
Yes, there is something you can do. I was in the same position you are in. Wayne gave me a list of capacitors that I could try in series with the HF driver. I found that a 0.1uF 630V capacitor did just what I was looking for. I believe the attenuation for that capacitor was 7dB.

Re: taming the piezoelectric [message #43882 is a reply to message #43880] Mon, 09 February 2004 07:17 Go to previous messageGo to next message
GarMan is currently offline  GarMan
Messages: 960
Registered: May 2009
Illuminati (2nd Degree)
Putting a resistor across the binding post or a cap in series with the tweeter will both tame the piezo, but in different ways. I found that the cap will attenuate the piezo, while the resistor "mellows" it out.

Values you may want to try are:
0.1uF for -6dB
0.3uF for -3dB

Try a 50, 22, or 12 ohm resistor across the binding post for a small, medium and large "mellow" effect.

Gar.

Re: taming the piezoelectric [message #43887 is a reply to message #43881] Mon, 09 February 2004 10:16 Go to previous messageGo to next message
wasteh202 is currently offline  wasteh202
Messages: 137
Registered: May 2009
Master
Thanks for the tips on the peizoelectric horn. I did not know about these tweak modifications, and I will try them.

I was actually thinking of tweaking the horn itself. Like adding mass to the back of the horn or opening the horn and treating the paper with something. I remember reading about these tweaks but do not remember the specifics.

I do know if these physical horn tweaks will get the exact change that I am looking for, and neither do not know exactly how to do them...

but... I will at least attempt the mods with the resistors.

Thanks much to GarMan and Gumby

Re: taming the piezoelectric [message #43888 is a reply to message #43887] Mon, 09 February 2004 11:10 Go to previous messageGo to next message
jlharden is currently offline  jlharden
Messages: 94
Registered: May 2009
Viscount
Hi waste,

I had good results with damping the back side of the piezo with mortite. I don't know if this will do what you are wanting though. There was also talk of disassembling the tweeter and using dammar varnish on the diaphram. If I recall correctly, this was from the single driver website where the Motorola piezo's get a decent amount of use. I haven't tried this and probably won't. The biggest difference in sound came when I switched from a pretty good quality solid state amp to a better push pull pentode amp. Better bass, midrange, and highs. Really transformed this speaker. I think the sound could be characterized as a warm, full bodied sound with hifi characteristics, yet possesing drive and dynamics not typically found in "hifi" speakers. In a nutshell: great sound with plenty of balls!
Good luck with your speakers and keep us posted. Jerrod

Re: taming the piezoelectric [message #43889 is a reply to message #43888] Mon, 09 February 2004 14:10 Go to previous messageGo to next message
wasteh202 is currently offline  wasteh202
Messages: 137
Registered: May 2009
Master
I may well change my amp for these speakers. I am using SS amps with them is this is likely part of the problem. I was using some Heathkit 4W-AM push/pull 20w monoblocks... but the sound was very bloated and unclear... much worse than the SS amps, perhaps the tubes... I'm not sure.

I will likly sell the Heathkit amps and look for some Bottlehead or Decware tube amplicication.

I will also attempt to treat the piezoelectric horn as you have stated and check to try to find the website that can tell me more about altering the inside of the horn...

Thank to all..

Re: taming the piezoelectric [message #43891 is a reply to message #43889] Mon, 09 February 2004 20:29 Go to previous messageGo to next message
steve f is currently offline  steve f
Messages: 236
Registered: May 2009
Master
Hi,
I tried a bunch of physical add ons to piezos. The worst was an automotive undercoat sealer. ( I'm always willing to make a mess in search of better audio!) I really like stuff like mortite or plumbers putty. It dampens the plastic a bit, and you can easily remove it if you don't like it.
Steve

Re: taming the piezoelectric, attn: Bill Epstein [message #43894 is a reply to message #43889] Tue, 10 February 2004 07:54 Go to previous messageGo to next message
jlharden is currently offline  jlharden
Messages: 94
Registered: May 2009
Viscount
Hello again,

I really like the push pull amp on horns. I've got tube power with a very big sounding 60 w/channel. I haven't heard the small signal tube amps on the 2 Pi's so I can't comment. My gut feeling is I'd like the sound, but crave the dynamics of the much more powerful push pull amps. I believe Bill Epstein has used both on Pi's, perhaps he'll comment. Either route should make great sound and warm up the room a bit! Good luck to you. Jerrod


Re: taming the piezoelectric [message #43898 is a reply to message #43891] Tue, 10 February 2004 09:37 Go to previous messageGo to next message
wasteh202 is currently offline  wasteh202
Messages: 137
Registered: May 2009
Master
good idea... I will go this route first. Thanks !

Re: taming the piezoelectric [message #43899 is a reply to message #43882] Tue, 10 February 2004 10:20 Go to previous messageGo to previous message
ports is currently offline  ports
Messages: 19
Registered: May 2009
Chancellor
Hello GarMan...I am in the process of assembling a"Quasi-Pi Theatre 3" using a Motorola CTS 1165a piezo tweeter instead of the Eminence PSD2002 compression driver...being an absolute novice to this I was wondering about how you installed the resistor on the piezo....do you just solder each end of the resistor to the "+" & "-" posts on the tweeter itself...I'm only beginning to gather the parts required...I have the Delta 12LF woofers, CST 1165a piezo tweeters,zobel network, & coil ...I'm still working on how to wire in the piezo(on paper)...I'm hoping to build cabinets later this year after my house renos are done. When things warm up here in Thunder Bay this summer I may get the chance to work outdoors !!!!

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