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I have a pair of RTR Model 4 Series III speakers with a 12" woofer, midrange, paper cone tweeter and horn piezo tweeter.
I'm thinking about disconnecting the piezo tweeter because it seems it isn't needed from listening I've done so far.
I'll use my ears to make the final decision on this but would appreciate any thoughts.
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Every piezo I've heard adds hardness to the sound.
Count all the exceptional speakers available today that use them. Yep, its zero.
Just a bit of trivia. You're basically correct. All commercial stock piezos were just the way you described. But there was one use of a modified piezo used for a short time in an interesting speaker made by Melos, the same company better known for its electronics, that worked quite well. The speaker was made for a short time before the amps and preamps and was quite unusual looking. It used a dynamic woofer, planar mid range and piezo tweeter and if you ever saw it you'd remember it.
While I wouldn't consider the Dahlquist DQ-10 a zero , I'd say that it could have been an even better speaker without that piezo-shit tweeter.Edit: You said "available today that use them". I missed that part.
Edits: 01/26/16
Even my favorite speaker of the decade, the Dayton-Wright electrostat added them to the MKII and MKIII versions.
As with the DQ-10, many users disconnected those horrible things. :)
A lesson regarding familiarity. In the late 1980s I joined an audio club, and had owned the DQ-10s for maybe ten years. A member was going on vacation for a couple of weeks, and offered me his Vandersteen 2C speakers to use while he was gone.
After listening to them for a couple of weeks, I put the DQ-10s back in the system because it was time for the Vandersteens to return home. I practically ran to the Dahlquist tweeter controls to turn them down as far as possible. Prior to that, I had grown accustomed to the rather bright piezos, and only really took notice of them after the comparison to the Vandersteens.
good friend of mine sold hundreds of kits replacing the dome and piezo tweeters on the Dahlquist with a single planar tweeter.
I replaced the piezos on mine with some JVC planars. Terminated the crossover section for the piezos with an 8 Ohm resistor to reduce possible interactions with the rest of the crossover, and crossed the 4 Ohm JVCs in around 12.5kHz with just a series capacitor and a fixed resistive L-pad, cutting output by about 4.5dB to match the dome tweeter. HUGE improvement in treble quality.
Some owners have removed both the piezo and its highpass section entirely, and replaced the original dome tweeter with a modern ScanSpeak unit that plays flat past 20kHz and has similar impedance/sensitivity specs to the original. Forget which ScanSpeak model.
Piezo tweets aren't ENTIRELY useless. You can hook 'em up to a small amp, and run a frequency generator set around 22kHz into the amp. DIY gopher chaser and neighborhood dog tormentor.
I found the piezos completely superfluous on the DQ-10. It's dome tweeter was not in need of extending.
I'd run and hide from those large PA speakers using banks of piezos all spitting at you at once!
You are going to change the crossover values by doing that.
And as mentioned if you don't hear it why change it.
If you are having a mirroring problem it's NOT your speakers but your amp setup. Look up that little thing called channel separation or imaging. Even cheap speakers image well with a good stereo.
Just been there dude! Off set tweeters are not going to fix that problem!
Definitely not having an imaging problem, but I'm open to seeing if I can improve on what I have.
You might just want to add foam or padding to the front of the speaker to stop reflections and increase imaging. Moving the drivers (destroying the cabinet) and/or also moving the drivers on the back of the front panel will make things worse with the reflections.
PeterZ
Thanks, I can try that easily.
I think you'll need to disconnect it before you can tell if it isn't necessary. It should be easy enough to disconnect if you can get inside the speaker cabinet. Try it and "let your ears make the final decision."
Good luck,
John Elison
Sure, EZ 5 min. job. Just pull off one of the input
connectors (hopefully not soldered)and tape the bare wire. I suspect they used it because the cone tweeter probably rolled off at 10K or so.I'd also replace any electrolytic caps in the crossover if you
have not already. I think at least one in there.
Edits: 01/25/16 01/25/16 01/25/16
Good point. I'll check to see where it rolls off. I replaced the capacitors years ago and added a low pass filter on the 12" woofer (it had none). It made a nice improvement.
You say that you cannot hear that the piezo tweeter gives you any benefit but you also give no indication that there is any disadvantage. So why not just leave it?
If I can use only one tweeter without losing anything I'm thinking about then changing the location of the tweeter and the mid range to be off center and on the inside of the cabinets (mirrored) to hopefully get better imaging.
Why not just sell them to someone who will appreciate them as they are instead of %$#@ them up beyond all redemption. The designers had good reasons for putting everything where they did, do you?
Edits: 01/26/16 01/26/16
What will you do with the three holes left from where the mid and tweeters were originally ? Especially as if you move the paper tweeters to the inside edge as it looks like one will need to occupy part of the cut out on the baffle which currently houses the piezo tweeter (if you go for mirror style).
I can only imagine doing this by replacing the entire baffle which will mean breaking the cabinet (from what I see from photos of the speaker) as the baffle does not appear to be e.g screw mounted making it removable but is simply glued in place. It strikes me that it would be easier for you to build another speaker from scratch or to buy an alternative.
NB: You will also probably have to fiddle with the crossover too, given what you intend.
NB: looking at the placement of the drive units on this model I can understand why you may find imaging less than optimal.
My first thought was to cut holes out of MDF and glue in but I was thinking I'd only have to move a mid in one speaker and a tweeter in the other. Now I see the baffles overlap so I'd have to move a mid in one speaker and both tweeters. More work than I thought. I could probably cut out a rectangle on the baffle and glue in MDF, maybe even add a brace if there is none.
Or, I could just buy new speakers and sell these.
And buy something decent. Seriously, those sort of '70s style butt-thumper speakers are NOT worth modifying, especially not in as complicated a way as you are contemplating.
Replacing the tweeters with a different type is also an option. I was looking on PartsExpress and there are a lot of options that look interesting for around $30 or less.
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