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| JEL N1600 Crossover |
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| JEL N1600C + HF EQ optimized for the 802 driver fitted with the original 16 ohm 20275 diaphragm |
The above crossover circuit, as discussed in this previous post, was optimized for my cherished pair of green Hammertone Altec 802Ds fitted with the original aluminum 20275 diaphragm, which has an aluminum wound voice coil. To my ears, this diaphragm has a more prominent midrange response which necessitates rolling off the upper midrange/lower high frequencies of the 414A woofer for flatter response.
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| JEL Universal Altec 2-way XO |
For the Altec 802 driver equipped with the 34852 (16 ohm) or 34647 (8 ohm) diaphragms, which have copper wound voice coils, I recommend the 6dB/octave crossover circuit below which is hinged at around 2500 Hz + high frequency EQ boost. This aluminum diaphragm has less energy in the upper midrange giving a tonal balance that sounds more extended in the high frequencies compared to its 20275 predecessor. In this implementation the Altec 414A woofer is connected as a full-range driver inspired by Joe Roberts.
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| JEL Universal Altec 2-way XO with HF EQ circuit |
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| Altec 414A + 32A/802/GPA 34852 + JEL Universal Altec 2-way XO |
I've also used this crossover successfully with the Altec 802 driver fitted with the Symbiotik diaphragm, Emilar EA/EC175 and Renkus-Heinz SSD1800/1400. Please take note of the different capacitor values for 16 or 8 ohm drivers.
Simplest Crossover
If you want the simplest crossover, my buddy Joe Roberts listens to his Altec 414A/802/32 set-up with the woofer in full-range mode + a 1.5uf paper in oil cap for the compression driver, no L-pad or HF peaking EQ circuit. See his Audiokarma post for more details.
Just wanted to say that based on this post by you I changed my crossover to your recommendation last night. I'm running 909A-16s with the 34852 'frams and 414-16Bs in 614 cabinets. I'm liking what I'm hearing so far. The midrange seems much improved - vocal presence is smoother and more beguiling, and the bass seems a little more defined. I also like the fact that the physical crossover is simpler. Thanks for continuing to lead me astray.:-)
ReplyDeleteI'm glad you found this useful. Happy listening and tinkering!
DeleteJE
Hi,
ReplyDeletewhat size awg 1mh inductor did you use? I am also trying to build the same crossover for a 802d/414z (2)
If memory serves me right this is the 18AWG air-core from Parts Express.
DeleteYes, I used the 1mH 18AWG air core Jantzen from PE.
DeleteHi,
ReplyDeleteI'm in the process of putting 2 ways Altec with 414z and 802D with your designed crossover. However I want to know where you can get the 30 ohm/2W L-Pad? I search but could not find where I can get it.
Radio Shack used to carry 25 ohm/2W WW pots which worked great in this application. But I've also used the Parts Express 16 ohm L-Pad, so all is not lost.
DeleteJE
Hi, Can I use your crossover for Altec 416 & 802D- both 16 ohms with 805 multicell horn.
ReplyDeleteThanks
This crossover was tweaked for my Altec 2-way system which consists of the 414 woofer + 802D compression driver mounted on the 32B horn. Thus, it is not suitable for the drivers you listed.
DeletePlease note that the 802D is a small format (1") compression driver and your 805 horns were designed for the large format (1.4") compression driver like the Altec 288. I am aware of 1">1.4" throat adapters but have no experience using large format horns.
I suggest you search for "Hiraga Crossover". Google will give you links that will give you ideas what can be done with the 416/805/288 components.
Good luck!
JE
I have a pair of 414Z and a pair of 414-16c that I'll try out in my two-way project with 802D drivers and 32A (metal) horns. Luckily, each pair has matching DCR. Do you have a recommendation for a starting point for the crossovers for each of the 414 drivers? It is my understanding that the 414Z is about three more efficient than the 414-16c, but that the 414-16c has a flatter response. Right now I intend to run my two-way speakers with a SV83-based SET that I'm building (~2 wpc). I'm relatively new to crossover design and I'm struggling to determine how to modify the XO for each 414 to derive the best sound from each relatively unique driver. Many thanks,
ReplyDeleteA good starting point would be to listen to your 414Z and 414-16C in full range mode to get to know them as I've discussed in this blog entry - https://jelabs.blogspot.com/2020/07/reality-check-musical-instrument.html - since this driver will be covering most of the fundamental frequencies in the audio band. Then add your 32A + 802D using a simple high pass cap (1uf > 4uf) + L-pad. By varying the value of the capacitor, you'll hear how your 802D + 32A drive/horn combo is adding higher frequency harmonic overtones.
DeleteUsing a crossover calculator + a simple iPhone RTA app will give you a visual clue as to what happens when you mess around with different cap values and L-pad settings. But always let your ears decide what sounds good, not the flatness of the trace or what people in the internet forums claim as gospel. That includes what you read in this blog. ;)
I know this is tedious and unconventional but after many years of being in this hobby, I've learned that "getting the numbers right" never coincided with what I hear in a concert hall.
Good luck and happy listening!
Thanks for the feedback. What I'm trying to learn has to do with how to treat the differences in efficiency between the two drivers with respect to how the crossover is designed and built. That is, I'm trying to find a starting point around which to experiment. I'm uncertain how to select the resistors and caps to take advantage of the attributes of each of the bass/mid drivers with the 32a/802d. This becomes somewhat more urgent when considering what a bushel of PIO caps will run for experimenting! Is it possible for you to offer a starting point for when I feel I've got a handle on the driver in full range? Thanks again.
DeleteThe starting point are the very simple XO circuits discussed above which don’t require bushells of caps and resistors. In my previous reply, I was trying to steer you away from a “formula attitude” which, from the tone of your reply, I’ve been unsuccessful. :(
DeleteBut I won’t give up just yet...
Forget the numbers because the 3dB difference you are getting hung up on happens mostly in the midband using “pink noise, “ not music. That’s why I wanted you to evaluate the “musical” difference between the Z and the -16C. Solid Grooves comment above should also give you a clue.
If you stop overthinking and installed either of your woofers in a 614 cabinet (or similar), wired up your 802D/32A to any of the above XO, you’ll probably get flatter RTA response from the -16C. The +3dB of the older Z might be manifested as too much overlap. BUT, which one gives you more musical pleasure? That’s the bottom line!
OK, I'll take a whack at it and report back. Thanks for your time.
DeleteHello, wouldn't a 8uf and 2uf in series result in a 1.6uf total?
ReplyDeleteYes!
DeleteThanks! So wouldn't that mean then that the crossover point is closer to 12000 instead of 2500hz?
DeleteThe 1uf (2uf) paralleled to 8 Ohm + 8 Ohm = EQ circuit based on the Altec 30923. Please Google it.
Delete