Tips for motorola piezo tweeters - diyAudio
Go Back   Home > Forums > Loudspeakers > Multi-Way

Multi-Way Conventional loudspeakers with crossovers

Please consider donating to help us continue to serve you.

Ads on/off / Custom Title / More PMs / More album space / Advanced printing & mass image saving
Reply
 
Thread Tools Search this Thread
Old 22nd May 2014, 04:29 PM   #1
diyAudio Member
 
Join Date: Sep 2013
Location: Mysore
Smile Tips for motorola piezo tweeters

Dear diy ERS
This is my first post at the forum . I have a stereo amplifier which I got it from a friend of mine with no brand name all I know is that it a 8ohm transistor amplifier which has a output of 450 w including left and right . I have slowly build up a 3 way system and I have today bought a pair of new piezo tweeters which is a Motorola KSN 1129A . and I have read in the forums that adding a resistor calms them down . out of what I have heard they are the best piezo tweeters. But the problem is I don't know what value of resistor should I add and how to add them. Please excuse me if I have posted in a wrong area I'm basically I am a newbie and I have been a reader of diy audio from a long time . cheers .
  Reply With Quote
Old 22nd May 2014, 04:44 PM   #2
GM is online now GM  United States
diyAudio Member
 
GM's Avatar
 
Join Date: Jun 2003
Location: Chamblee, Ga.
Greets!

These normally answers all folk's questions:
Frugal-phile | Piezo Tweeter Crossovers | J Risch
Pulsar Developments Ltd - Piezo Tweeter Application Note

GM
__________________
Loud is Beautiful if it's Clean! As always though, the usual disclaimers apply to this post's contents.
  Reply With Quote
Old 22nd May 2014, 04:54 PM   #3
diyAudio Member
 
Join Date: Jul 2004
Location: Sthlm
Not sure if the same info maybe is in the other links posted, but this seems informative:

Using piezo tweeters wisely: a "how to" - AudioKarma.org Home Audio Stereo Discussion Forums
  Reply With Quote
Old 22nd May 2014, 05:41 PM   #4
diyAudio Member
 
Join Date: Sep 2013
Location: Mysore
Thanks for the quick reply fellas. I just looking into the crossover after reading the useful info you guys sent, for tweeter the crossover has a 3.3uF capacitor. So can I still add a 22Ohm resistor in parellel?
  Reply With Quote
Old 23rd May 2014, 06:40 AM   #5
diyAudio Member
 
Join Date: Sep 2013
Location: Mysore
Thanks for the info GM and Kris0603 I went through all the info you guys sent me and I added a 8ohm resistor in parallel and voila ! I didn't go for the 22ohm resistance idea though cause I didn't want to take any sort of risk with the amp or crossover. From the sound quality I hear now I think they are better than the peerless 1inch 8 ohm metal dome tweeter many people recommend. The highs are shrill but in a good way ,instruments like violin sound excellent. Thank you guys for all the help.
  Reply With Quote
Old 24th May 2014, 06:58 AM   #6
diyAudio Member
 
Moondog55's Avatar
 
Join Date: Jun 2007
Location: Norlane; Geelong: Victoria: Australia
I'll ask here rather than open a new thread
Just opened a box I offered to look at
Somebody has "Improved" a standard party speaker until they no longer work.
One speaker has the piezo tweeter shunted with 10W47R the other is miswired with the 10W47R in series with the piezo tweeter
Woofer is run open and a pretty standard cheap 6R 12 inch
New owner does charity gigs at for OAPs so I don't want to do anything that costs him too much.
I was thinking of 4uF and 1R1 in series but should I replace the shunt with a lower value or is 47 Ohms OK?
__________________
QUOTE" The more I know, the more I know, I know (insert maniacal laugh >here<) NOTHING"
  Reply With Quote
Old 24th May 2014, 08:26 AM   #7
diyAudio Member
 
Join Date: Dec 2012
Location: The Jurassic Coast, England. GB
Send a message via Skype™ to JonSnell Electronic
Piezo tweeters do not require any form of crossover due to the attributes of the elements used. It is a good idea, in larger systems, to fit a 24Volt 10Watt bulb in series with the tweeters. This reduces the high power and will reduce the risk of damage to the piezo element. Smaller systems will improve with a 4R7 to 22R0 resister in series, depending on the quantity of tweet required. One can use a 22R rheostat.
__________________
www.flyingmole.co.uk For World Wide support for Flying Mole, Class D, Refurbishment and Repairs. www.jonsnell.co.uk
  Reply With Quote
Old 24th May 2014, 11:08 PM   #8
diyAudio Member
 
Moondog55's Avatar
 
Join Date: Jun 2007
Location: Norlane; Geelong: Victoria: Australia
Thanx John but that doesn't answer my question.
I need to attenuate the highs, they are very loud and very harsh and Left is quite different sounding to the Right
L has the 47R resistor in series and R has it in parallel
__________________
QUOTE" The more I know, the more I know, I know (insert maniacal laugh >here<) NOTHING"
  Reply With Quote
Old 25th May 2014, 12:04 AM   #9
diyAudio Member
 
Moondog55's Avatar
 
Join Date: Jun 2007
Location: Norlane; Geelong: Victoria: Australia
I just found an original Motorola document on-line
Tweeter in these boxes is the KSN 1016A
I'd like to give these boxes back "Better" than when made if possible

Some-one tried to make these a 4-way by adding an after market XO and adding in a midrange and a tweeter and stuffed up the wiring



http://linear1.org/i/piezo.pdf
__________________
QUOTE" The more I know, the more I know, I know (insert maniacal laugh >here<) NOTHING"
  Reply With Quote
Old 25th May 2014, 12:16 AM   #10
JMFahey is offline JMFahey  Argentina
diyAudio Member
 
JMFahey's Avatar
 
Join Date: Mar 2009
Location: Buenos Aires - Argentina
The proper use for the 47r resistor is in series with the capacitive (Piezo) tweeter .
resistor in parallel on the other cabinet is obviously a miswiring and does nothing useful, it only sucks power from the amp and turns it into heat.

If the tweeter is too loud , you can pad it 6dB which should be more than enough with a 47r resistor in series and another 47r resistor in parallel with the tweeter.

You could add a switch which connects/disconnects the 47r resistor in parallel with the tweeter, the series one should be always there.
  Reply With Quote

Reply


Hide this!Advertise here!
Thread Tools Search this Thread
Search this Thread:

Advanced Search

Posting Rules
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is Off
Trackbacks are Off
Pingbacks are Off
Refbacks are Off


Similar Threads
Thread Thread Starter Forum Replies Last Post
Would a piezo disk from a Motorola tweeter make a good strain guage? kelticwizard Everything Else 25 11th April 2013 03:41 PM
piezo tweeters peter day Everything Else 21 9th April 2012 02:42 PM
Motorola Piezo HF any good? rotaspec Multi-Way 5 13th December 2009 10:17 PM
4" Seas long throw woofs, Motorola piezo compression drives, TangBand 2" widebands mr_ro_co Swap Meet 4 15th April 2008 01:16 AM
Piezo Tweeters subwo1 Everything Else 6 22nd August 2002 11:46 PM


New To Site? Need Help?

All times are GMT. The time now is 11:24 PM.


vBulletin Optimisation provided by vB Optimise (Pro) - vBulletin Mods & Addons Copyright © 2014 DragonByte Technologies Ltd.
Copyright 1999-2014 diyAudio

Content Relevant URLs by vBSEO 3.3.2