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What to do with Altec 420Y Drivers?

Sorry to be so slow...

I've got limited web access here at a hotel at the Outer Banks. Anyway, the original cap in the 872B's was a 6uFD and I changed it to an 8UFD for the CV tweeters I put in. I do want to add an L-pad to tweak them a little, but frankly I love these speakers as-is, and prefer them to the Klipsch Chorus I's I have in the same room. If you'd like, I'd be happy to send you the ultralinear tweeters I also tried in these cabinets for the price of shipping, and if you like them, pay me what you think they are worth. If not, you can send them back. They are almost a perfect fit, and I never did play with different caps to change the X-over freq. If you have Zilch as a willing collaborator, you should be most of the way there...I'll bet he'll like playing with the 420's, 'cause even if he doesn't want to admit it, he has already been assimilated....:D

PS and if you decide you don't like the 420's you could always sell them to me.....:D:D:D:smoke:
 
analog addict said:
Zilch as a willing collaborator, you should be most of the way there...I'll bet he'll like playing with the 420's, 'cause even if he doesn't want to admit it, he has already been assimilated....:D
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Not hardly, you've got more work to do -- I just whipped these together last night in a moment of weakness.

I know, I know, if I was using Altecs, I wouldn't need no steenkin' subs. :p:

[Just one more to load now.... :thmbsp: ]
 

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Mxlews Madrid:

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Well guys, I've "seen the light". Zilch has shown me that you really can't rely on your ears to tell the good from the bad when it comes to speakers. You just don't know what your missing. I'm going to be scrounging up the money for horns and will be loading a pair of JBL clone cabs instead of these Altecs, as the Altecs won't fit the drivers well. Thank you very much, Zilch. :yes:
 
You're very welcome, Mxlews. It was my pleasure providing a "short course" in comparative speakerology today, not to mention having the opportunity to measure your Madrids.

Here's the synopsis, from my perspective:

1) See the RTA plot, first above. This 420Y with tweeter disabled does have extended high-frequency range, but only to 4.2 kHz. It's down 10 dB at 4.8 kHz, and continues to fall above that, except for a shelf between 6 and 9.2 kHz at -15 dB. The bass response in freefield (away from wall and floor boundaries) was somewhat lacking, and rolls off at 50 Hz. Under these conditions, there is also rising lower midrange, peaking at 600 - 800 Hz. The bass would likely be improved by placement on the floor and against a wall.

2) We added an Eminence-based Crites tweeter, actively crossed at 3.5 kHz, which filled out the VHF to nearly 20 kHz, and we also engaged a sub to help the bass. It sounded fine, but I'd have to say, "Mediocre." Test disk was Santana.

3) We then switched out the tweeter for a BMS 4552 on JBL PT waqveguide, and lowered the crossover point to 2 kHz. The improvement was significant and immediately apparent.

4) See the MLS curves, second, for the response of the drivers. The red curve shows the 420Y response in more detail. It exhibits a major (-10 dB) notch just above 2 kHz; a lower crossover frequency, perhaps 1.2 or 1.5 kHz, would have been a better choice, as the two drivers did not sum well in that notched region.

5) We investigated the 420Y response further by varying the lowpass filter frequency while playing pink noise, a very sensitive subjective listening test. The notch was apparent, but more importantly, the HF response above that had an unpleasant coloration. I suspect the notch represents the transition to the inner Duo-flex cone.

I note that the above relates to but one sample, which may not be representative of the class. However, it clearly serves as indication that others would warrant similar evaluation. We had a second sample on hand, but these findings were sufficiently conclusive for mxlews to decide upon his future course with the Madrids....
 
Hi, I have the Altec 420Y biflex with EV-t35 tweeter and EV XO 36 (3500hz) all in the altec cabinet 870B system, Best regards
 
Hi, A question, is possible to add to that configuration Altec 420y + EV tweeter T35 (XO 3500 HERTZ), a horn, yes is thus, as would the indicated?, I thinking about small horn for the Set, Thanks, Martin
 
PT waveguide is 12" wide by 6.5" high.

It won't fit in Madrid, will fit Santana.

Dump the T-35s, and use 420Y as woofer only....
 
Zilch, I finally found this thread. Were those the 4550 or 4552's you have in the big cabs? They were sweet sounding. These were the speakers I listened to for almost an hour. This photo is missing Zilch's top secret port tuning device though. :D

attachment.php
 
Hi, Duffinator!

The PT waveguides in these are the more expensive 1.5" throat version, so the drivers are BMS 4555, the same combination Jackgiff is using in his Santanas:

http://audiokarma.org/forums/showthread.php?t=117212

They don't make a neodymium version of that, but I'd likely be using it, if they did. :yes:

You saw the JBL Nd drivers for these, but the $$$ puts them out of the question, nearly tripling the system cost.

[I AM building another pair with those for comparison, tho, now that the proprietary tuning works.... :D ]

*****

Mxlews is just finishing up his pair in vintage boxes. Expect an "unveiling" here soon.... :thmbsp:
 
Actually, I'm talking about the HF compression drivers. The BMS are $115 each, about the same as 4550s; the JBL Nd ones are more than 10X that.

The waveguides are $100 apiece as opposed to the $10 version we're using in "economy" implementations with 4550/4552.

Regarding the bass, the woofers are $300 each, but, as we have discussed, only one is required per cabinet to make the bass you liked. The dual-woof thing is developmental, and, well, "excessive."

The white-driver subs in the middle weren't playing, of course, because I had worked out the LF tuning in the mains. :yes:

[When Mxlews heard them, we were still running the subs in lieu of the second woofers.... ]
 
Zilch said:
Actually, I'm talking about the HF compression drivers. The BMS are $115 each, about the same as 4550s; the JBL Nd ones are more than 10X that.

The waveguides are $100 apiece rather than the $10 version we're using in the "economy" implementations with 4550/4552.

Regarding the bass, the woofers are $300 each, but, as we have discussed, only one is required per cabinet to make the bass you liked. The dual-woofer thing is developmental, and, well, "excessive."

The white-driver subs in the middle weren't playing, of course, because I had worked out the LF tuning on the mains. :yes:

[When Mxlews heard them, we were still running the subs in lieu of the second woofers.... ]
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Got it. The expensive ones were sitting on top of other cabinets. There were so many goodies in your "Lab" that I was overwhelmed. :thmbsp:
 
Well, the "BS-Free Zone" IS gettin' kinda cramped.

It's time to move out some of the earlier projects, probably.

The Minis are staying, tho:

http://audioheritage.org/vbulletin/showthread.php?t=10038

[They don't take up much room.... ;) ]

*****

I know, I know, off-topic, but they were/are FUN!! :banana:

[And the thread illustrates the typical development process here.... :yes: ]
 
MartinV56 said:
Thanks Zilch, and what crossover would you suggest?
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We offer two options in the E'Wave thread. I don't recall the sensitivity of 420, but I'd start with the high sensitivity version. It's easily converted by swapping in a few inexpensive components.

MartinV56 said:
Econowave is a tweeter?
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Mid/high, actually, and unlike any tweeter you've ever heard before, most likely.... :thmbsp:
 
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