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First listen to the 3-way; I call them the...... [message #50531] Sat, 13 January 2007 20:38 Go to next message
Bill Epstein is currently offline  Bill Epstein
Messages: 1088
Registered: May 2009
Location: Smoky Mts. USA
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BatSpeakers:

The 2226's cut off at 350Hz have the best sound I've ever heard from them.

The 2123 is the kid in the front row waving his hand in the air; "ooh, ooh, call on me!!!" They definitely need to be padded down a little.A 1 henry series coil didn't do anything but introduce some distortion so I'll try something like a 10 ohm shunt and a 20 or 30 ohm series resistor. It needs to come down about 4 dB.

The Fountek CD-2 ribbon lends some nice air and, I think, a bit of transient oomph way up high on cymbals. hard to tell though with the 'bad boy' waving his hand around.

I wonder if taming the mid-driver was what led Dave Cope to call off his FrankenSpeaker project with the TADs?



Re: Question about attenuating the 2123 [message #50532 is a reply to message #50531] Sun, 14 January 2007 02:24 Go to previous messageGo to next message
Bill Epstein is currently offline  Bill Epstein
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Registered: May 2009
Location: Smoky Mts. USA
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I'm looking at the Pi compenation networks. 600Hz, 6dB calls for R1 = 8ohm and R2 = 16 ohm with 4.7uf by-pass on R1.

Is that where I want to be attenuationg the overall output from 300 to 4000 Hz?

Re: First listen to the 3-way; I call them the...... [message #50533 is a reply to message #50531] Sun, 14 January 2007 10:28 Go to previous messageGo to next message
spkrman57
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Registered: May 2009
Illuminati (1st Degree)
Bill,

Have you confirmed proper polarity and voice coil alignment for proper phase results?

I don't understand how a coil in series with the 2123 introduces distortion???

Run your coil in series with the 2123 with a 20 ohm resistor across the terminals of the 2123 and tell us what happens!

Ron

Re: Question about attenuating the 2123 [message #50535 is a reply to message #50532] Sun, 14 January 2007 11:43 Go to previous messageGo to next message
Wayne Parham is currently offline  Wayne Parham
Messages: 18789
Registered: January 2001
Illuminati (33rd Degree)

Oooh, that's sweet, Bill. You have all the right stuff for a great speaker.

For your midrange driver, you don't want to use the attenuator configuration I use for compression tweeter padding. It is a special case where I want a specific load on the crossover that makes it underdamped. I do this to create a shelved region for a couple of octaves between the crossover frequency and the HF range where augmentation begins. So this kind of network allows some peaking to develop.

Instead, you want something closer to what I use on the midhorn in the seven π. Its job is to provide pure attenuation without allowing peaking or providing excessive damping. It provides a little bit of damping, but it is pretty much a matched load. I suggest the same thing would probably be good in your speaker.

Try this and see how it sounds for you: Assuming your midrange is an 8Ω 2123H, use an 8Ω resistor in shunt across the midrange driver and a 4Ω resistor in series before that. If it's a 16Ω 2123J, use a 16Ω shunt and 8Ω series resistor instead. For a crossover, try running it wide open and see how that sounds as a full range. You might add a coil to tame the top end a bit. Start off with values around 0.5mH for a 2123H or 1.0mH for a 2123J. I wouldn't use a capacitor, allowing the woofer and midrange to overlap. They're close enough they'll act as a single source at low midrange frequencies anyway because they'll be within 1/4λ of each other.


Re:Very bad news about the 2123's [message #50540 is a reply to message #50533] Tue, 16 January 2007 11:36 Go to previous messageGo to next message
Bill Epstein is currently offline  Bill Epstein
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Registered: May 2009
Location: Smoky Mts. USA
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It seems that 'distortion' is blown voice coils on both!

Re:Very bad news about the 2123's [message #50541 is a reply to message #50540] Tue, 16 January 2007 15:24 Go to previous messageGo to next message
Wayne Parham is currently offline  Wayne Parham
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Registered: January 2001
Illuminati (33rd Degree)

What a bummer! The recone kit is available, but it's pricey.

What caused them to fail? I know you aren't running big amps. Maybe they were blown when you got them? Did you buy them used?



Re:Very bad news about the 2123's [message #50542 is a reply to message #50541] Tue, 16 January 2007 16:46 Go to previous messageGo to next message
square peg is currently offline  square peg
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Registered: May 2009
Esquire
Yeah, they were used and a good deal but sat on my shelf for about 2 years so there's no going back to the seller, who you know BTW.
I'll try some Delta 10's Ron has and he has a line on getting a recone at a price which is a lot more than I paid but still less than retail.
I've made about 50 transactions with used stuff over the past 5 years and this is the first disappointment I've had. Not too bad.

Re:Very bad news about the 2123's [message #50543 is a reply to message #50542] Tue, 16 January 2007 19:28 Go to previous messageGo to next message
Wayne Parham is currently offline  Wayne Parham
Messages: 18789
Registered: January 2001
Illuminati (33rd Degree)

Buying used JBL Professioanl Series drivers is not much of a risk. You really can't go wrong because, with few exceptions that have no recone kits available, you can refirbish them to be as good as new. I'd recone your 2123's sometime, no matter what else you do. Keep 'em alive.


Re:Very bad news about the 2123's [message #50547 is a reply to message #50540] Wed, 17 January 2007 14:41 Go to previous messageGo to next message
dB is currently offline  dB
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Registered: May 2009
Master
I'm sorry to hear that.
Two speakers (8ohm)(bass+mid) in parallel go under 4ohm. Double check xover and Lpads before you get (0?/1/2 or) to low impedande. Play carefully. Have a drawing first, maybe that helps if it was that.
Regards (I still love your Tweeters). Maybe they just don't match the ribon's.

Re:Very bad news about the 2123's [message #50549 is a reply to message #50547] Wed, 17 January 2007 16:59 Go to previous messageGo to previous message
Bill Epstein is currently offline  Bill Epstein
Messages: 1088
Registered: May 2009
Location: Smoky Mts. USA
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Thanks for the suggestion. I wish it were that. The 2226 and 2123 are both 16 ohm.
Pressing lightly on the cone in just the right place while playing makes the distortion worse.
Game over.
However, just to be certain, I'm taking them down to Speakerman's on Saturday to put them on Woofer Tester.

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