Melded piezo array switching - Full/Half/Off

Helpful hints on how to build 'em, and where to get the stuff you need.
Message
Author
User avatar
LelandCrooks
Posts: 7244
Joined: Thu May 04, 2006 9:36 am
Location: Midwest/Kansas/Speaker Nirvana
Contact:

Re: Melded piezo array switching - Full/Half/Off

#16 Post by LelandCrooks »

Yes.
If it's too loud, you're even older than me! Like me.
http://www.speakerhardware.com

ONvENTURES
Posts: 9
Joined: Sun Mar 23, 2014 12:00 am

Re: Melded piezo array switching - Full/Half/Off

#17 Post by ONvENTURES »

How do I wire 6 tweeters with a dpdt switch?

Bruce Weldy
Posts: 8301
Joined: Fri Nov 27, 2009 11:37 am
Location: New Braunfels, TX

Re: Melded piezo array switching - Full/Half/Off

#18 Post by Bruce Weldy »

ONvENTURES wrote:How do I wire 6 tweeters with a dpdt switch?
Not sure why you'd want the half off option. When people put in that switch, they usually have a melded array with at least 12 piezos. So, their half off still has 6 running. Since you have only 6, you may want to just try it with a straight on and off setting. Not sure there would be that great of a difference between 3 and 6 that a little EQ couldn't fix.

6 - T39 3012LF
4 - OT12 2512
1 - T24
1 - SLA Pro
2 - XF210


"A system with a few knobs set up by someone who knows what they are doing is always better than one with a lot of knobs set up by someone who doesn't."

CoronaOperator
Posts: 1648
Joined: Wed Mar 25, 2009 7:07 pm
Location: Medicine Hat, Alberta, Canada

Re: Melded piezo array switching - Full/Half/Off

#19 Post by CoronaOperator »

Bruce Weldy wrote: Not sure why you'd want the half off option. When people put in that switch, they usually have a melded array with at least 12 piezos. So, their half off still has 6 running. Since you have only 6, you may want to just try it with a straight on and off setting. Not sure there would be that great of a difference between 3 and 6 that a little EQ couldn't fix.
I think the "half" setting is not for tone control but rather to decrease the height of the array in order to increase the vertical dispersion of the tweeters. Useful is the cab is on the ground on backline duty so that you can hear the highs as the performer.
Built:
17" width 10" driver Autotuba
2 x 29" width dual Lab12 Tuba60
6 x DR250 2510/asd1001
In progress:
2 x DR250 2510/asd1001
For best results, point the loud end of the array towards the audience

Bruce Weldy
Posts: 8301
Joined: Fri Nov 27, 2009 11:37 am
Location: New Braunfels, TX

Re: Melded piezo array switching - Full/Half/Off

#20 Post by Bruce Weldy »

CoronaOperator wrote:
Bruce Weldy wrote: Not sure why you'd want the half off option. When people put in that switch, they usually have a melded array with at least 12 piezos. So, their half off still has 6 running. Since you have only 6, you may want to just try it with a straight on and off setting. Not sure there would be that great of a difference between 3 and 6 that a little EQ couldn't fix.
I think the "half" setting is not for tone control but rather to decrease the height of the array in order to increase the vertical dispersion of the tweeters. Useful is the cab is on the ground on backline duty so that you can hear the highs as the performer.
Well, that could be - but unless you are 10 feet in front of the cab, I don't think there is enough difference between half and full in vertical dispersion to hear the difference. And by going half, you've cut the sensitivity in half also.

I just don't see this as being worth the trouble with only 6 tweets.

6 - T39 3012LF
4 - OT12 2512
1 - T24
1 - SLA Pro
2 - XF210


"A system with a few knobs set up by someone who knows what they are doing is always better than one with a lot of knobs set up by someone who doesn't."

wocketpatch
Posts: 33
Joined: Mon Oct 01, 2012 9:28 am

Re: Melded piezo array switching - Full/Half/Off

#21 Post by wocketpatch »

I guess I still don't follow. I'm not sure whether it was confirmed that it cannot be wired to HALF in the middle position, or if that was meant to be a description of how to do it. Thanks for any help.

wocketpatch
Posts: 33
Joined: Mon Oct 01, 2012 9:28 am

Re: Melded piezo array switching - Full/Half/Off

#22 Post by wocketpatch »

Regarding the question asked by ONvENTURES, can anyone confirm that this modification to the diagram would work for a 6 piezo array?

Image

Does this make sense, or what should be done differently?

User avatar
Tom Smit
Posts: 7457
Joined: Sat Jan 05, 2008 1:24 pm
Location: Sarnia, Ont. Canada

Re: Melded piezo array switching - Full/Half/Off

#23 Post by Tom Smit »

wocketpatch wrote:I guess I still don't follow. I'm not sure whether it was confirmed that it cannot be wired to HALF in the middle position, or if that was meant to be a description of how to do it. Thanks for any help.
It cannot. The centre terminals will be connected to either one end or the other end; thus, the switch's centre position is "off".
To further explain: imagine holding the "hashed box" in the picture between your index finger and thumb (thumb on the left side) on your right hand. Now rotate your hand 90 degrees counter-clockwise, and this gives you the picture beside the hashed box.
wocketpatch wrote:Regarding the question asked by ONvENTURES, can anyone confirm that this modification to the diagram would work for a 6 piezo array?



Does this make sense, or what should be done differently?
The diagram works. However, you might want to have the top 4 "on", or the top 2 "on" when in the "half" position. The fewer tweets that are on, the more vertical dispersion you will have. As was stated earlier, even 6 tweets open up the vertical dispersion significantly.
TomS

wocketpatch
Posts: 33
Joined: Mon Oct 01, 2012 9:28 am

Re: Melded piezo array switching - Full/Half/Off

#24 Post by wocketpatch »

Thanks, does this change represent what you are suggesting?

Image

User avatar
Tom Smit
Posts: 7457
Joined: Sat Jan 05, 2008 1:24 pm
Location: Sarnia, Ont. Canada

Re: Melded piezo array switching - Full/Half/Off

#25 Post by Tom Smit »

Yes, it does.
TomS

wocketpatch
Posts: 33
Joined: Mon Oct 01, 2012 9:28 am

Re: Melded piezo array switching - Full/Half/Off

#26 Post by wocketpatch »

OK just one more question.. In the version below, should I wire the two outliers (in the top right of the diagram) in series as shown, or would it be better to do those two in parallel? Does it even matter? Any other thoughts on this arrangement are welcome before I heat up the iron as I'm finding the impedance question seems to be a somewhat different one than what I'm used to with regular drivers. Thanks again.

Image

User avatar
Tom Smit
Posts: 7457
Joined: Sat Jan 05, 2008 1:24 pm
Location: Sarnia, Ont. Canada

Re: Melded piezo array switching - Full/Half/Off

#27 Post by Tom Smit »

Leave them in series.
TomS

User avatar
Bill Fitzmaurice
Site Admin
Posts: 28619
Joined: Tue May 02, 2006 5:59 pm

Re: Melded piezo array switching - Full/Half/Off

#28 Post by Bill Fitzmaurice »

Bruce Weldy wrote: I just don't see this as being worth the trouble with only 6 tweets.
+1.

User avatar
Clef's of Bass
Posts: 60
Joined: Sat Dec 26, 2020 4:21 pm

Re: Melded piezo array switching - Full/Half/Off

#29 Post by Clef's of Bass »

Questions about tweeter switching:

I'm currently building a J15 paired with an 8 ohm Delta lite 2515 and 20 piezo tweeter melded array.

I presume that the piezo crossover would be at 8 ohm as well, wired in parallel with the 15 making the cab's impedance @ 4 ohm?

I'm planning on wiring in the 3 way tweeter switch (bass player here).

If the tweeter is switched to half, or off would it change the tweeter's impedance? or would it stay @ 8 ohms regardless of switch position?

I'm asking this because I'm still deciding on an amp head. 8)

Grant Bunter
Posts: 6915
Joined: Mon Nov 28, 2011 11:12 am
Location: Ilfracombe Queensland Australia
Contact:

Re: Melded piezo array switching - Full/Half/Off

#30 Post by Grant Bunter »

Clef's of Bass wrote: Fri Jan 15, 2021 7:35 pm Questions about tweeter switching:

I'm currently building a J15 paired with an 8 ohm Delta lite 2515 and 20 piezo tweeter melded array.

I presume that the piezo crossover would be at 8 ohm as well, wired in parallel with the 15 making the cab's impedance @ 4 ohm?

I'm planning on wiring in the 3 way tweeter switch (bass player here).

If the tweeter is switched to half, or off would it change the tweeter's impedance? or would it stay @ 8 ohms regardless of switch position?

I'm asking this because I'm still deciding on an amp head. 8)
Hi, and welcome to the forum :)

Your cab will be a nominal 8 ohm load.

Half/on/off switching shouldn't really affect impedance to much as the piezo's are parallel/series wired, and the woofer low pass is 8 ohms.

A bit further down in my way old plans, it says:
electric bass doesn’t need the high frequency sensitivity of a full array. These concerns are addressed by using only four to ten tweeters in a melded array, or two to six in a flat array. To maintain adequate power handling wire a two-tweeter flat array in series; the other tweeter count options are wired series/parallel.
Built:
DR 250: x 2 melded array, 2x CD horn, March 2012 plans.
T39's: 4 x 20" KL3010LF , 2 x 28" 3012LF.
WH8: x 6 with melded array wired series/parallel.
Bunter's Audio and Lighting "like"s would be most appreciated...

Post Reply