New (To Me) Altec 414-8B

Picked up a pair of rather scruffy but good sounding Altec 414-8B yesterday for a good price. (based on what I see online) I've admired all of the wonderful Altec systems for years but they were just too rich for my blood until this pair showed up locally on Facebook marketplace. Carefully cleaned as much dust, wood chips, dead bugs etc. as I could off the surrounds. I recently completed some 4+ cu ft boxes for some cheap GRS 15" woofers. (pics below) I really don't want to build another set of boxes. If I made an additional front baffle to mount to the front of the existing box would that work? Should I front mount or rear mount? I see both in online pics. As far as HF goes I'll probably need to go with something economical instead of pursuing the Altec 511, 811, 32 route plus the expense of drivers. You can see my Blanda Bowl/Fostex ff85wk solution in the pics. I've also experimented with Pyle PSD442/Dayton H07E horn driver combo that were decent for not much money. Looking forward to this project. Thanks for any suggestions. Oh, by the way, the GRS 15" I used were not bad sounding, a little boomy. Just hoping to experience some Altec magic.
 

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I finished the adaptor rings needed to allow me to use the 414-8b in my 4 cu ft boxes I originally built for GRS 15". Pics below. On Jennifer Warnes, Diana Krall, Ray Brown/Soular Energy they sound amazing running full range. Unfortunately, when I switched over to some big orchestral like Shostakovich Sym. #5/Pittsburgh SO the highs would tear your head off. Soooooo...full range may not be an option. I was hoping to copy JE's crossover on his 414/32/802d. Looking online, I found this Zilch crossover for 414-8b using a BMS compression driver and horn. However the 3mh inductor has me concerned that by crossing that low I'll lose some of the Altec midrange magic. Any suggestions? Thanks.
 

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Hi @tubav, I'm not familiar with any of the HF drivers you mentioned.

But hopefully you might get some ideas from what I did below.

The 414Z is running unfiltered. I used 2 x 0.25uf PIO caps in series with the Selenium ST324 - a budget tweeter inspired by the classic JBL 2405 slot loaded super tweeter.

This set up sounds quite decent to my ears. No nastiness in the upper midrange/lower treble.

Essentially the 414Z is reproducing all the fundamental notes up to around 3.5 - 4 kHz, then the ST324 covers the upper harmonic overtones.

Maybe a 0.47/0.5uf cap will work with one the HF drivers you already have?

DSC07625.jpg

The quality of harmonic overtones is very important to me, which is why I highly recommend the use of the 32 horn + an 802 or 806 driver above the 414.

Good luck!
 
JE, thanks for your reply. For HF I could try my Fostex ff85wk, GRS PT2522/waveguide, Linaeum tweeter, and Pyle PDS442/Dayton H07E that Michael Chua recommends. The thing that disheartened me was the big orchestral stuff and how the highs just tore my head off. I was running the 414-8b wide open with no HF drivers just to get used to the sound. I was not expecting that and it kind of bummed me out.
That led me to believe I couldn't run them wide open. My amplification is decent, Heathkit W3M, Bottlehead preamp, etc. Thanks again. I'm kind of partial to Pittsburgh SO because I'm a retired middle school band director and one of my former students is the bass trombone player in Pittsburgh.
 
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Wait a moment…I thought you were using HF drivers on top of the 414-8B when you heard harshness. I never experienced upper midrange harshness from unfiltered 414As, Zs or -16Bs. But then, I never handled the -8Bs. Weren’t those used in the 9849 monitors. Are the cones original?

I do remember, you’re a musician too!
 
I believe the cones are original but I'm pretty ignorant on all this. I don't have a lot of experience with vintage drivers. The seller showed me the Altec stamps on the inside of the cones signifying originals. Thanks.
 
Voice coils are not rubbing as far as I can tell. The unpleasant sounds are just on high frequencies. I'm going to try some small inductors to try and roll them off before the issues come in. Thanks.
 
Making progress! Yesterday I tried a XO I found online for the 414 using a 2nd order XO plus zobel. I quickly realized I was giving up a lot of the Altec 414 magic. So I tried a few simple things such as letting cabs fire straight ahead and backing off a touch on volume and not pushing them quite so hard. Instantly better. As stated earlier, I'll need to keep my HF options on the economical side. I have some Linaeum tweeters left over from some old RS Optimus LX5. Did a simple 1st order with a single 4.7uf cap. To my surprise they matched levels perfectly with the 414 without any padding resistors, at least to my ears.
 

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I've been listening for the last 3 1/2 months to my scruffy Altec 414 8b using Pyle PDS442/Dayton H07E horn and driver combo. For the XO I used the Salectric 414 for the bass and a simple 2nd order for the horn/driver crossing at approximately 1250hz. The reason for the Pyle/Dayton combo is that they are in my price range and received a high recommendation from Michael Chua at Ampslab with the FR graphs to back it up. My cabs are 4.2 cu ft that I built for some 15" last summer and made adaptor rings for the Altecs. I really like the looks of the gray Altec 614 utility cabs and am toying with the idea of building a pair of those. Will I hear any improvement over my current cabs or am I just trading one for the other? Attached are pics of my current setup. Thanks for any suggestions.
 

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I am not sure what your vent tuning is looking like, as the cabinet is roughly the same size as a 614 (+ ~.2 cf?) and it uses a 7"x2"x11/16" vent. I would just be looking at optimizing the vent, not trading cabs.
 
Thanks for your reply. According to the old Altec brochure with pics of the utility cab, it is 3 cu ft and mine is 4.2 cu ft. The vent I currently use is 4" x 4" round.
 
A 614 is 20.5x24x14.25 according to the cab plans I have, which is ~3.9 cf.

altec614.jpg

How long is your vent?

7*2*11/16=67.375

67.375/12.566 (the area of a 4" circle) =5.362
 
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4" diameter, 4" long. The Altec utility is a little smaller than the standard 614 cab according to this old Altec brochure. Thanks for your help.
 

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@tubav I dont know what I was doing with my vent calculations above. They look totally wrong to me now, as 7*2*11/16=9.625 actually. I was at work and must have hit the wrong keys somewhere in a rush.

If I use a proper vent calculator, it looks more like it should be a shade over an inch.

1708638104118.png


<hangs head in shame>
 
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