DIY custom front loaded bass reflex speakers

[lgvenable]

I've been trying to figure out a way to do use JBL 2202's or 2206's, along with 2445J's & 2385 horns, and a 2404H.

While I could do a passive system, and mount them in a box, like the JBL4732; which actually would be easy if I wanted to do Jammin Jersey...

What I think I'd rather do is build custom boxes, using the Altec 816 cabinet plans, and mount a single 2202 or 2206. Then, either externally mount a 2445J/2385 horn, and a 2404H, or alternately add a smaller separate section above the 816 cabinet to hold these two (with the 2404 on top).

I've got several questions so bear with me:

I'm going to tri-amplify the speaker; using AB Systems 713A mono tri-amplifier (500-250-250 @ 8 ohms).
1st:
While the amp has active setting for x-over points:
where is the best place to x-over the 2202/2445J-2385 (500HZ)??
where is the best place to x-over the 2445J2385/2404 (???HZ)
2nd
Since the Altec 816 plans are for 15's can I just proportionally alter the design once I get it into autocad via a friend? Since the JBL Pro enclosure guide says 1.5 ft3 for an enclosure, how is this cabinet volume affected in a a front loaded horn?
3rd
Can I just redesign the cabinet to yield the appropriate volume suggested in the JBL guide? How much dampening should I use?
4th
The JBL guide also says 80HZ with a hole apparently (3/4" deep), as the port. I know how to use winISD, can I design the horn to give more like 50HZ, or should I stick with 80hz, and just use my 2245 sub for the lows?
5th
While the Truextent diaphragms sound like they improve the harshness of the AL diaphragm, can I have the current Al diaphragms aquaplased to help improve the harshness?

As a point I've already got a dBX driverack 260 to use to set the crossovers, as well as setting the time delay to time align the horn and the woofer.
6th
However, is there a link where I can go learn the needed principles and math to determine how much time alignment is needed? (or will the driverack do all that as I use it to setup the speakers after building them??

I'm sure there will be more questions as I start this new project to redo the front center, left and right with these cabinets.

Or after saying all that, does someone have a better idea to follow (short of saying Chuck all those older parts for what you can get; and then spend major money on all new stuff).

I'm old school, so the idea of using all these drivers I acquired from the Chicago Museum of Science and Industry is just too much fun to pass up, as I recreate their pre-IMAX theater over my garage in my bonus room.;)

[SMKSoundPro]

In my boxes I built, I used two 2225 15's, then into a 2445/2385, then to a 2402 bullet.

I use a 4way crossover and have found 800hz from lows (woofers) to 2445, then 8khz from 2445 to 2402.

I have a separate crossover to drive the 4 2441 subs undrneath from 80h down to 20hz.

The 2225 lows run from 60 - 800hz.

My question is: Why use a 2202 or 2206 12" for lows? Did I miss something here?
Where is the bottom coming from?
scotty.

[jcrobso]

My 2 cents!
The two 2206s in that large tuned box did put out very good bass down to 40hz. When I playing around with a pair I was very impressed at the bass, the two 12" equaled a 15" but with better transient response.
The SR4732 sounded like a monitor speaker, very clean and balanced, but was sound reinforcement speaker.

The Altec 816 is a small front loaded horn that will give you good mid range but at the lows blow 120hz will not be there. Most front loaded horns/reflex suffer from poor low bass response. The JBL 4560 is a bigger reflex box than the 816 and suffers low bass loss as well.

[lgvenable]

the 2202's came in since I have 6 of them in great shape. But in searching I found conversations where Mike Caldwell was talking about them being better at hi fi than 2206's.

The jist was the 2206 is built for power, was better at sound reinforcement, whereas the 2202 was better for hifi.

if the loaded horns blow for bass below 100 to 120 hz, then I can just build a 4732 box to replicate a real 4732; or alternately buy a pair of empty boxes from Jammin Jersey ($400), and build the other box I need from the box design once I get them (easiest).

Winisd seemed to point to lowest port tuning at 79HZ with the 2202 when I built a box, with a bunch of parametric eq to get the response flat.

How about this, a 2206 and a 2202 in the same cabinet, aided by the 2445J-2385 horn and a 2404H baby cheeks, so you get the mids from the 2206, and 50 hz from the 2206; as power is not the issue with the mono triamp I use. And I'll use the driverack 260 to eq the signals to each speaker set?

The actual theater had a set of 2240's and 2245's which were on either side of the auditorium (about 12 of them); but they used 2202's as the mid bass drivers, 2445-custom horns for mids, and the 2404's. However since the custrom horns were so large I didnt go that route, as they're built for an auditorium; they're nice; just way big.

As for where do the lows come from i my setup? I have a DIY 2245 running 600 wpc mono; I attached its pic into this post. I also had a 4719 with 2 x 2240's, but Scott is getting thosem, and I'll probably convert the box to a single 2245 to match the box below (as its about the same size.)

[jcrobso]

The 2202 is a mid range, while the 2206 is bass speaker.
Since you have 2245 sub just use the 2206 from 100hz up to the X-over point to the 2445. Not sure how putting a 2206 and a 2202 in the same box wourld work.

[lgvenable]

How about something from left field?

What about a 4 way, 2206 bass/2202/mid-bass; 2445J-2385 mids-horn, 2404H HF? Control the 2202/2445/2404 with one drive rack, and the 2206 with a second.

Or.....I've got mono equalizers which could handle the 2206 with high and low pass filters , as well as boosting the signal to get flat response, then use the 2202's, 2445's and 2404 controlled by a driverack 260 to equalize the upper end.

Or is that unnecessarily complicated?

The comment was made the 816 is no good below 100 to 120 HZ

Take the case of a 2206, if the box is built and port tuned to say 50HZ, you're going to get 50HZ belted at you correct?

So my next question is: if you build a 816 cabinet and design it to match the correct box volume(as you designed above); and then port tune it to 50HZ; you're going to get 50HZ out of the horn correct? The addition of the horn structure doesn't lower the bass output due to some sort of negative interaction with the horn structure does it?

While I like the look of the 816, I mocked up the horns on top of a box, and they remind me of some of the old VOTT speakers. Especially if I use the horns I got from the museum (see attachment). Problem is the room I'm using right now is 30 ft long and 18 feet across; but the custom horns are made for a 250 person theater; as opposed to the 2385 bi-radial horns, which fit a home venue much better.

In 11 years when I head for Oklahoma & retirement, I could use the larger horns, since I plan on a 50 x 65 room, with walls you can walk behind for the theatre. Bur right now the bi-radials are a much better fit.

Any help or suggestions are appreciated, as I'm ready to start cutting wood once the weather is a little better.;)

[lgvenable]

winISD says 1 2206H in a1.5 ft3 box port tuned to 65HZ gives the attached response, pretty flat down to 80 HZ (THX territory), so I could do either:
25HZ>2206@80 or 100HZ>2445J-2385 @ 800>2402@8000HZ

while I've heard several comments like your about the 4732, what does the second 2206 per speaker win me?

The sound engineer I work with on my amps uses 4732's in all the local events he does in Evansville/Newburgh.

WinISD says I'ce got to go 3 ft3, and then I basically have twice the speakers at the same point, and I guess reinforced bass. But strictly speaking you get there with 1 speaker at 1.5 ft3 port tuned to 65HZ. ;)

I'll be driving these at 250-150-150 (woof-mid-HF), so its not like I'm lacking for power into the speakers.

So why go for 2 x 2206 in each speaker?

plot 1 (1.5 ft3 1 x 2206H)....80HZ
Plot 2 (3.0 ft3 2 x 2206H)....80HZ....identical curve

[1audiohack]

If I still follow correctly you have the VLF covered with your 2245 right? Just one? If so a pair of 2206's can overrun a single 2245 in a room the size of yours, so can the 2445/2385's.

Unless you need a ton of impact and have more than one sub, I think one 220X each side would be the best option, reason being it is hard enough to get two drivers at crossover to behave much less two drivers doing the same thing over a wide band width. For the same reason, and an order of magnitude more difficulty I would not entertain having two nonidentical drivers (2202 and 2206) sharing the a baffle over the same bandwidth.

If you had two DBX260's you could run dual mono with each configured 4,5,or 6 way for all the flexibility and control you would probably ever need. For time alignment I have everyting you have except 2202's and could set up a like stack and give you the delays ±. The DBX can't do that for you, and the quest can drive one mad.

[lgvenable]

Audiohack;
That pretty well sums it up. I threw out that idea as a wild card, but after today the 2206/2445/2404 is THE way to go. I had a chance to listen to some 4732’s today; they did sound very good.

Good enough to make me say, >>>just do it the easy way. Then out of NO WHERE I stumble across a pair of BRAND SPANKING NEW 4512LF cabinets. They were still in the JBL boxes; they’re lie 15 to 16 years old and never had a speaker in them! The guy I’m getting them from bought them years ago for a project (like I’m doing), and just never got around to doing it.

We’re both Texas Ex’s, so when the conversation turned to stereo, he ended up asking me if I’d be interested in them. I was dumbfounded; but quickly said yep.

Got both of them for 190 shipped to me; and already have excellent condition 2206’s to populate them with. Brand New!!!! They’re not made anymore, and I’ll bet these are the best examples in the nation.

So I guess I’ll do right and left with those, then build a new center with a DIY 4512 cab, and build custom enclosures for the 2445-2385 and the 2404H for each channel. Which pretty much is what you've said to do.

I thought that a single 2206, combined with a 2445/2404 combo; would do a pretty good job on the front channels…..

The 4732 sounded great, but these 4512LF’s looked sexy & sinister and I couldn’t pass them up; it felt like Karma that they got offered to me; right at the moment when I’m ready to build this hardware.. .

The JBL white lettering on the side is pristine, without a flaw. They’ve never been out of their boxes. I knew exactly what he had when I saw the first pictures. Unbelievable. When I told him what they were , then he said he had wanted to sell them to another JBL fanatic but all these every-other-guys were a bunch of idiots who didn’t know their collective rears from a hole in the ground; so he had held on to them for years. When he realized I knew the 4512's came out of the box port tuned to 60HZ when 2206's were added and that I KNEW JBL like he did >> the deal was struck.

Meanwhile currently, for subs… I’ve got the DIY 2445, and also have a SR4719 cabinet; which I just sold some 2240’s out of.

I plan on converting it to a single 2445, by building a new front for it, and port tuning it to 25HZ too. The I'll store the twin speaker front for posterity. So I’ll have two 2245’s each eq’d by a driverack 260 & driven 600 wpc (by 2 separate bridged AB Systems 821's). (instead of a DIY 2445/4719w/twin 2240's)

After building the 4516 and horn enclosures (front left right center), I can eq and time align those with the 2nd drive rack.

Then…I guess I can sell the 2202’s, and let them fund driverack 260#3, and later in the year start working around the room, as I have enough 2445’s and 2404’s to do all 7 channels ; with extras for spares.;)

My L100T days are numbered.....and the best part > my better half is hoping the new speakers are smaller. Ho Ho Ho!!

[1audiohack]

Way to go with the new cabs! What are the chances of that happening? You are in for some fun!
All the best,
Barry.

[lgvenable]

I kinda fell into these. Two newbs to LHF were talking in a thread about liking to flag stereo stuff on Craigslist. I basically said, I barely have enough time to work and jump on LHF at night. And that perhaps they needed to get a life.

But they were from from like Seattle, and were bombing folks on Austin's Craigslist??!!

So bingo off I go to Austin Craigslist; search JBL; and low and behold found the 4512's. Called, hit it off with the owner, and got them. Took like 45 minutes to make contact.

Here they are what do you think? I'll do the measurements, and have a friend CAD them so I can post them for members to use as LF bass boxes, since the 2206-2445-2404 is a popular combination.

The light marks are from dust in his storage, he said they're pristine
So this promises to be too cool. Like I said, I felt like it was Karma; since I was looking to do something like this, and these fell into my hands .

I always get to read about others great little stories, now I have one too.;)

Once they are here I'll fill er up, and repost; meanwhile I'm getting my AB Systems 713A's mono tri amps warmed up, I'll need them soon!:D

the literature says 60 HZ (or 50) port tuned (out of the box = literally!).

[hjames]

Pristine is right - wow! Congrats on your good fortune - a great tale indeed!


I kinda fell into these.

So bingo off I go to Austin Craigslist; search JBL ...

The light marks are from dust in his storage, he said they're pristine
So this promises to be too cool. Like I said, I felt like it was Karma; since I was looking to do something like this, and these fell into my hands .

I always get to read about others great little stories, now I have one too.;)