Altec 414z enclosure guidance

[jaaronb]

Hey folks - looking for the collective Altec wisdom of some AKers for an Altec project I have in mind.

I'm in possession of a working pair of Altec 9844 monitors, with 2 x 414z drivers, 806a/811b horn per side. As the WAF on these speakers is expressed in negative double-digits, I'd like to use these components to make a simple pair for hi-fi home use.

For simplicity's sake, I'm envisioning a single 414z driver per side, with the 806a/811b horn outside the 414 enclosure.

At this point, I've read everything out there I can find on 414 drivers and people's various projects employing them - here in AK and on the various Altec forums, and while they melted my brain, none of them showed a project built to completion along the lines of what I'm envisioning, which is:

- passive crossover - I'm willing to (rebuild) my own if necessary, but don't want to biamp or use an aftermarket active crossover.

- no Onken cab. I'd love to try the Petite Onken one day, but their size is a no go for domestic purposes right now, and the build is a bit daunting too.

- Decent bass response - I don't need flat to 30hz (and know these drivers don't do that), but I'd like good quality LF as low as reasonably possible in a simple enclosure. I quit using subs years ago, and have run British monitors like Harbeth since, so I don't mind 40hz it higher roll-off, but I'd like to get as much as I can out of the 414z.

- MLTL or bass reflex seems the best way to go. I read the epic thread on one of the Altec forums where GM helped a user get *close* to a MLTL design based around the 414. I've also seen the awesome JE Labs 2-way build (http://jelabs.blogspot.com/2014/01/altec-2-way-horn-system-redux.html?m=1), which is about the closest thing I've found to what I'd like to do.

- I know the Altec 614 enclosures used in the JE Labs project are specified for the Altec 414, but they are on the small side, and If prefer something big enough that stands aren't necessary.

Has anyone out there ever tried using the 414 drivers in the classic Altec 612/Lansing Iconic enclosure?

At ~6 ft³ the 612 enclosure doesn't exceed Altec's guidelines on enclosure volume for the 414... and in the Altec Avalon, there is precedent for an Altec-produced single 414-based speaker in a Carmel (or Malibu or 9844)-sized enclosure. But I've never come across a project based on the 414 in a 612 enclosure.

If I were to try the 414 in the Altec 612 enclosure, how would I go about tuning the front vent to an appropriate freq (~40hz?) for the 414z. Is there a program out there for calculating that?

I've messed around in WinISD, but I'm not confident enough in my ability to imagine a speaker's voicing based on the graphs to run with a particular design. I'm not really of the view that ruler-flat response sounds best... If I had to choose, I'd typically prefer to listen to a euphonic system over an analytic one any day.

I want to capture the magic of these speakers in an aesthetic format that will make my wife inclined to let me stay around, so I'm open to any suggestions you might have.

I think the 612 design (https://encrypted-tbn2.gstatic.com/...jyQaY_BZnVhoeaoeg_U9_zLV9JA4nzbGA_PNdU39Y3mug) would pass the test, even with horns on top of the cabs.

Amplification is a ~10 watt SET for now, but y'all know how that goes...next week it could be MC30 monoblocks, or a 40-watt push pull. But generally speaking, it'll be lowish-powered, quality tube amplification.

Any thoughts? I've scoured the four corners of the Internets for an answer to this and haven't come across one. Apologies in advance if I'm missing something obvious. And many thanks in advance for any guidance!

 

[elitopus]

I use some 414-16b in small (1.5cuft) cabs in my living room. I used some horns I got from parts express with Renkus 1" comp drivers. Crossover is a single cap on the horn. 414 are run wide open and the horn is brought in high. Cabinets are tuned to 65hz.

My wife lets me keep all the big speakers in the man cave. This is the biggest size allowed in the living room.

The bass response is obviously not the same as the correct size box, but still sounds very good in room

I have run these with quite a few receivers and amps. I used a tube 5wpc SE 6bq5 for a while.

Cabinets are Marantz imperial 7 that I repurposed. They are unfinished under the grills. They were free

I don't think you need anything crazy. Just build a box that looks good enough and tune it per the size

 

[bowtie427ss]

You are bound by compromise.

One of the bits of magic in the 9844 is that the tandem 414's as oriented have a polar pattern that well matches/mates that of the 811 horn. The dual motor, tandem arrangement also makes for sensitivity and dynamic tracking that balance very well with the 806/811. You will lose all of this.

The other potential caveat i see is with a larger volume box, you will lose linearity in the 414's upper end response, and that's where much of their magic lives.

 

[jaaronb]

Thanks very much for the feedback.

Those look great elitopus - how high does the cap being the horns in? It's encouraging to see that a set up like this is enjoyable, if not optimal.

Bowtie - I know your familiarity with the 9844 and other Altec designs far exceeds mine - really appreciate your perspective on this.

I know this is stretching your comments a bit, but do you believe the sonic virtues of the components/design of the 9844 exceed those of any/most single 414 + 806a/811b arrangements, or only such arrangements within the limitations I laid out above?

I guess I'm curious if there even is a single 414 + 806/811b arrangement that could come close, or if I should instead try to optimize (aesthetically) the 9844 design, eg, Heathkit as-21, Carmel or even Malibu.

Thanks again folks - looking forward to this project.

 

[elitopus]

When I put these together I got half a dozen cap values. I ended up liking the 1.5uf the best. On paper that should bring the horn in around 6.5khz. I would have to measure the Renkus driver to see what it is actually doing. All I know is at that xover point I don't need any HF attenuation.

Its a really good sounding combo to me. And this was the only way I could get some Altec's in the house.

 

[bowtie427ss]

do you believe the sonic virtues of the components/design of the 9844 exceed those of any............................

Heck no! 9844's have plenty of caveats of their own. They just happen to have the positive attributes i mentioned above.

I guess I'm curious if there even is a single 414 + 806/811b arrangement that could come close,

Certainly the 414 has lots of potential, the 806/811 combination not as much. I understand your desire to try to optimize LF output. But, the 414's strengths really reside in the other direction, in 2-way systems employing a higher XO frequency in the 1200-1600hz range.

I'm listening to 9849-8D's as i type this. They use a 414, and a driver based on the 806 on a 32B bent horn. I think these cabinets are a bit over 2cuft and one of the few vintage Altecs that use port tubes of actual length. XO is 1500hz with a zobel. These are my daily drivers in the house for the time being. So good, that i have little motivation to build more system in here. They're no longer stuffed in the corners atop stacked 9844's as in the pics, they are now in near field use flanking either side of my desk.

http://www.lansingheritage.org/images/altec/plans/1970's-lf-plans/enclosures20.jpg

http://www.lansingheritage.org/images/altec/specs/pro-systems/9849-8a-8d/page02.jpg

 

[Tom Brennan]

I never heard a woofer with better midrange than that of the 414. Some speakers do better bass than the good Altecs, some do better highs. But nothing does better vocals. My opinion ya understand.

 

[jaaronb]

Thanks again - this feedback is very helpful. I'm much less concerned with bass extension than I am with capitalizing on the 414's midrange strengths, and to the extent possible, using the 806/811b since I have them.

WRT a single 414 per side set up, it seems the consensus among folks who've posted in this thread so far is to go with smaller <3ft³ boxes with higher crossover freq to the horn.

With a set up like that - which is similar to the 614 enclosure - what kind of usable low end extension do you get? ~50-60hz?

Perhaps something that splits the diff. between the 2.5 ft³ of the 614 and the 6 ft³ of the 612 is worth considering?

As I mentioned above, if there were a proven MLTL design, I'd likely go with that.

Aside from the aesthetic issue with petite Onkens, I've heard mixed things about them with 414s.

At this point, I'm most likely to go with either the 614, which seems to be the most proven 414 enclosure (and was recommended by Altec) or a 612.

 

[bowtie427ss]

Perhaps something that splits the diff. between the 2.5 ft³ of the 614 and the 6 ft³ of the 612 is worth considering?

Somewhere in the depths of this place is a thread where the late great Zilch assisted another member(skywaverider) with a modded X-over for his 9844's whereby one woofer played up to meet the horn, but the 2nd woofer was filtered above ~150hz and functioned mainly as a "helper" woofer to augment the lowest octaves. Perhaps that system of components and network in cabinet of Malibu proportions would be a consideration for you.

 

[jaaronb]

Somewhere in the depths of this place is a thread where the late great Zilch assisted another member(skywaverider) with a modded X-over for his 9844's whereby one woofer played up to meet the horn, but the 2nd woofer was filtered above ~150hz and functioned mainly as a "helper" woofer to augment the lowest octaves. Perhaps that system of components and network in cabinet of Malibu proportions would be a consideration for you.

This is a great idea I hadn't considered Bowtie. I did make my way through most of that thread, but hadn't thought of the possibility of using Zilch's crossover in something like the Malibu enclosure.

Going to look into that as a possibility and will report back.

Thanks again for the assistance.

 

[elitopus]

One of the good things about the Malibu is they get the horn up closer to ear level. I had to put little risers on my cabs. Sitting directly on the floor they sounded muddy and lifeless.

Since you are building the cabs you can shape them however you want.

 

[Xtinc]

I'm using a pair of 414-8Cs in Barzilay cabinets. I picked up the empty cabinets locally and satisfied with the bass output. I believe they measure somewhere between the 614 and 612 cabs.

 

[elitopus]

I'm using a pair of 414-8Cs in Barzilay cabinets. I picked up the empty cabinets locally and satisfied with the bass output. I believe they measure somewhere between the 614 and 612 cabs.
View attachment 867351

Nice!

Those look to be about the same width as my 612c cabs. I think the 612's are slightly taller though.

What crossovers are you running with those?

 

[Xtinc]

Nice!

Those look to be about the same width as my 612c cabs. I think the 612's are slightly taller though.

What crossovers are you running with those?

Thanks. I'm running a Altec N801-8a on bottom and a JBL on top, forget the model, but it crosses at 7000Mhz.

 

[jaaronb]

Great point elitopus. Has anyone heard the Malibu? I'm wondering what they sound like relative to 9844. Looks like the internal volume of the Malibu is >8.

Also would love to hear from anyone who has heard the Avalon. That's a single 414 in a big Carmel-sized enclosure. Interestingly, the Altec plans for the huge Carmel enclosures include the option of a single 12" driver.

Regardless, I started from the assumption that using single 414s per side would be simpler, and due to phase issues and such would sound better - but perhaps I shouldn't have excluded dual 414s up front. Could a vertically arranged dual 414 setup - whether per Zilch's 2.5 way crossover, or with the original network - give me the magic of the 414 with some added LF authority?

Thanks one again all - I'm in your debt for all the great info and experience you've shared.

I haven't made it all the way through the skywaverider thread yet (need to assemble a few days' worth of food/water), but am hoping to get through it today.

 

[bowtie427ss]

(need to assemble a few days' worth of food/water)

What is your general location?

 

[jaaronb]

Thanks. I'm running a Altec N801-8a on bottom and a JBL on top, forget the model, but it crosses at 7000Mhz.

These look outstanding! Did you alter/tune the vent for the 414s?

One thing I'm uncertain of is how one would go about tuning the port for the 414 for a given enclosure size and geometry. Also, what frequency should the vent of a 414 BR enclosure be tuned to?

 

[bowtie427ss]

Also, what frequency should the vent of a 414 BR enclosure be tuned to?

depends on the box volume and XO target freq, probably the best way is to model it in simulation software which will require the input of several parameters. I'm not sure that reliable T/S parameters are published for your model of 414. I'm not nearly qualified enough to do the long hand math to work it out the way the Altec engineers did.

 

[phil-g]

depends on the box volume and XO target freq, probably the best way is to model it in simulation software which will require the input of several parameters. I'm not sure that reliable T/S parameters are published for your model of 414. I'm not nearly qualified enough to do the long hand math to work it out the way the Altec engineers did.

I seem remember there was a way of inserting a piece of tube and cutting it until you got the response your looking for. but I may be wrong

 

[Xtinc]

These look outstanding! Did you alter/tune the vent for the 414s?

One thing I'm uncertain of is how one would go about tuning the port for the 414 for a given enclosure size and geometry. Also, what frequency should the vent of a 414 BR enclosure be tuned to?

Thank you. The baffles were installed in the cabinets when I got them and have a 6x2" slot port with no length extended behind the baffle. I haven't taken the time to research/modify them, just been listening...maybe one day.
Bowtie427ss is correct using driver parameters and software such as Bassbox to calculate. I'm sure a few members here would be willing to assist if provided the required data.