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Re: 2 x Jack 112 Lite
Posted: Wed Apr 17, 2013 8:20 am
by Charles Jenkinson
This is what I think the phase tester circuit looks like.
Re: 2 x Jack 112 Lite
Posted: Wed Apr 17, 2013 5:08 pm
by AntonZ
I think you should be good with that wiring.
Re: 2 x Jack 112 Lite
Posted: Sun Apr 28, 2013 4:35 pm
by Charles Jenkinson
Well, once again I'm in a bit of a pickle with this phase testing. I've tested all my piezos. I reckoned on initial testing that 14 were out of phase and 24 were in phase (total 38). But I've just tested a sample of 3 of the out of phase ones and reckon 2 of those are now in phase and one is still out of phase. Bottom line, I have difficulty saying what is louder and quieter when I flick the phase swapping switch over. Worse still, if I swap ears round, one ear 'measures' the sound difference one way and the other ear measures it the other way, for the same piezo, without moving anything other than the switch! If I use both ears head-on, i.e. don't rotate any individual ear to the sound, it's almost impossible to distinguish any difference, to me, though there sometimes appears to be a 'pitch' change rather than an intensity change or it seems to alternate which tweeter the sound is coming from when the phase on just one changes. The wiring is correct mind you. I'm using white noise with the 'HF Generator' (from
http://www.hfaudio.ca) available on line. I don't like to feel I'm getting anal about this, but my hearing isn't that bad, and I'm not getting anywhere fast, so it might be time to just pot-luck it and ignore the results of the 'test' - which is what bothers me more than anything, that this is turning out to be subjective rather than objective. I could always come into the shed every day for the next fortnight listening to 'in phase' and 'out of phase' piezos, refining which box they should or shouldn't be in. The good news is, I took another broken one (in the plastic horn surround) apart and the element came out no probs. It was a bloody loud one too! On that sample of one, I'm wondering if the glued ones are more damped than the unglued ones, and therefore quieter.
Re: 2 x Jack 112 Lite
Posted: Sun Apr 28, 2013 4:48 pm
by Bill Fitzmaurice
Charles Jenkinson wrote:what bothers me more than anything, that this is turning out to be subjective rather than objective.
Probably. I doubt the numbers that you gave for how many were bad. A switching circuit is not required. Designate one tweeter as the control, it stays plugged into the sound source. A second set of leads are attached to it. The tweeter being tested is placed right next to the first, the second set of leads attached to it. if the volume goes up it's correct, if it goes down try it the other way. It's best not to rely on your ears as testing devices, they are neither accurate nor reliable. A sound meter should be part of your kit.
Re: 2 x Jack 112 Lite
Posted: Mon Apr 29, 2013 4:08 am
by Charles Jenkinson
Bill Fitzmaurice wrote:It's best not to rely on your ears as testing devices, they are neither accurate nor reliable. A sound meter should be part of your kit.
Thanks Bill. This is the nub of it. I'd been assuming folks just used their ears. So when you test phase, do you use an SPL meter?
Re: 2 x Jack 112 Lite
Posted: Mon Apr 29, 2013 6:49 am
by Bill Fitzmaurice
Charles Jenkinson wrote:So when you test phase, do you use an SPL meter?
I do.
Re: 2 x Jack 112 Lite
Posted: Tue Apr 30, 2013 3:35 pm
by Jools4001
Oops...appear to have replied to what I thought was the last post in the thread only to find the thread went on for several more pages....just ignore me, I'll go way now

Re: 2 x Jack 112 Lite
Posted: Tue Apr 30, 2013 4:07 pm
by Chris_Allen
Jools4001 wrote:Oops...appear to have replied to what I thought was the last post in the thread only to find the thread went on for several more pages....just ignore me, I'll go way now

Been there, done that.
Re: 2 x Jack 112 Lite
Posted: Wed May 01, 2013 1:24 am
by Charles Jenkinson
Jools4001 wrote:...only to find the thread went on for several more pages....
...ain't that life.
Do share, please.
Re: 2 x Jack 112 Lite
Posted: Wed May 01, 2013 12:43 pm
by Charles Jenkinson
How's this for lining the back of the jacks? It's 15mm thick at the bottom of the troughs, and 45 thick overall. It popped up on Amazon as a bargain when i was searching for an spl meter.
Re: 2 x Jack 112 Lite
Posted: Wed May 01, 2013 8:42 pm
by biggerrigger
I hope it's ok Charles, I just used the same product to line all 4 of my DR250's. Seemed to my ears to do the job quite well.
Re: 2 x Jack 112 Lite
Posted: Fri May 03, 2013 1:28 pm
by Charles Jenkinson
Noise maker and noise meter.
Finally phase testing.
Re: 2 x Jack 112 Lite
Posted: Fri May 03, 2013 1:30 pm
by Bill Fitzmaurice
Charles Jenkinson wrote:Noise maker and noise meter.
Finally phase testing.
Place the mic about three feet from the tweeters, otherwise you might be reading mainly one or the other.
Re: 2 x Jack 112 Lite
Posted: Fri May 03, 2013 3:48 pm
by 88h88
Sup kid?

Re: 2 x Jack 112 Lite
Posted: Tue May 14, 2013 6:57 am
by Charles Jenkinson
A query on array construction:
Will the ABS cement adequately glue or fix (painted) birch dowel in for the diffuser rod on the arrays?
....5/8" OD rigid PVC pipe is proving elusive. Aluminium tube is pretty available also, in 5/8" OD, thin wall.
Cheers,
Charles