Altec 12/15 'alternative'...

I've been enjoying the system for the last few months, but have wanted to try a bit steeper crossover as I was hearing a bit of a lack of clarity in the crossover region (~2k). So, I put together a quick 3rd order Butterworth, centered at 2000hZ today and have had a few hours of listening.

I am liking what I hear so far, better clarity, and it seems like a bit tighter bass. More listening needed.

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I've made a few changes recently that I'll highlight below:

1 - Removed one more of the rear panels on the LF cabinets. This immediately improved the tone of the LF, got rid of a bit of a boominess, and improved overall balance quite a bit. I am very pleased with this change. I've listened to it for ~4 weeks at this point, and will be making a tweak soon to try and improve it a bit more.

2 - I recently scored some nice big Dayton AMT's from @Pat McGinty and I've added them into the system to give me a bit more top end. Some REW measurements showed me response was dropping off after 11-12k'ish. My hearing is really only good to 16k or so, so the response of these AMT's is great for me. They are huge, and frankly, not an ideal match in this system, but they bring a lovely bit extra to the top end. Their efficiency puts them just slightly below that of the woofer, and so far that balance sounds nice. I will likely pad the mid-horn down a bit and see if I like that balance, but for now, I'm listening to it in a somewhat laid back configuration.

I'm also considering making some horns for the AMTs, I think with a good horn they would sound even better, and I believe I would get a small efficiency boost, and potentially some better pattern control.

Caps from previous crossover experiments and clip leads for now, I will likely try to order some nice russian pio's and bypass with kp1832's for them long-term.

A few pics of the very quick and dirty, scrap recycling mounts:

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I like the addition of the AMTs, I’ve had good results using them with horns. I also like your idea of making a horn to try with them.
 
I've been enjoying the addition of the amt, but it's just not quite efficient enough to match well in the system. I'm pulling them out, and am saving them for a future two-way idea.

I'm going to be installing my DE-250s on RCF HF-101 horns for HF duties, I'll be crossing them in around 10khZ, first order. I'll need something to match their efficiency with the mid-horn/driver combo, so I'm using a pair of Atlas Sound AT-100's. I've found these to work surprisingly well, I've only ever used them above ~300hZ or so. They don't have the granularity of the Slagle or Wanusch(sp?) autoformers. They are a nice, very inexpensive tool for prototyping crossovers, better for impedance matching than an l-pad imo.

With these additions/changes I decided I wanted a bigger platform to mount everything to, that would allow me room to modify/tweak more easily. I'm also trying some new capacitors for the first cap in the mid-horn, 3x 1uF / 1000v Russian paper in oil caps, the last cap for the mid-horn is a 10uF/400v ASC pp, bypassed with a 0.1uF/3kv CDE 940 series pp. I've also added better swamping resistors on the autoformer primaries. I upgraded a couple of the inductors to copper foil types as well.

I'm hoping to wrap up the construction in the next few days and get some listening time in to tweak later in the week. For now a few pictures:


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Looking good Gable. How do they sound compared to the big rig behind them? I also run boxed woofers, midrange horns, and the Big A$$ Heils for tweets. but I am embarrassed to show you my crossovers compared to yours.
 
I haven't integrated the DE-250s yet, but I've used them many times. I have both Ti diaphragms and polymide. The Ti extends higher, but the polymide is definitely a bit smoother, especially lower. In HF configuration I'll probably try the polymide diaphragms first.

Hopefully by this weekend I can get some time to swap things out and have a listen.
 
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