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Discussion Starter · #1 · (Edited)
There has been some interest in a DIY version of this speaker (with cd and woofer options) that I built a couple years ago so I thought I'd put together a list of parts and information on how to build a set.

Here is a list of parts you'd need:
JBL 4722 Crossover 442144-001
JBL 2384 Waveguide
Compression Drivers: JBL 2453h-sl, 2452h-sl or 2450h-sl (all discontinued but can be found if you look hard enough)
Woofers: 265h-sl (stock), 2265h, 2225h or 2226h will work with the stock crossover (haven't personally used the 2265h)

Cabinet would need to be 4-5 cubic ft per driver so 8 - 10 total (I built them into 2 stacked enclosures) tuned to 40hz. If you go larger you could possibly tune lower as well if you wanted them for music otherwise if crossed to a sub 40hz is the recommendation from JBL.

I have the 2453h-sl installed now but also plugged in the older 2450h-sl to test and they sounded very nice as well. The top end on those was a little more rolled off creating an warmer sound but I imagine eq would work as well. Based on the 4722n speaker thread, the 2452h-sl would be an upgrade from the 2453 but the difference is near indistinguishable.

The woofers were all compatible around the crossover interesting enough but they all had slightly difference responses below. I didn't think any of them sounded different enough in my room to worry about, room eq would shape the rest anyway.

Some construction pics for inspiration:

3114888


3114889
 

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Nice.

You should try those in an mtm config, just keep the waveguide at ear level. The 2450h-sl has a different phase plug and will not extend to as high frequencies as the 2453h-sl or the 2452h-sl. The 2265hpl would be my choice of woofer.

I'm curious about some of the 2452h copies I've seen on ali... I might try them out at some point.

Anyway, at some point, you may want to scrap the network and go with a digital xover. It makes a nice difference having steep filters, good time alignment, and more control over the fr.
 

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Discussion Starter · #3 ·
A custom active crossover will be the next step but that will need to wait awhile. Just finished my basement and will soon being upgrading to a 9.2.6 layout. Need to build my surrounds and atmos first.

Have you gone active on your 4722s? I know many in the JBL thread are and some even copied the active settings from the crown amplifiers.
 

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A custom active crossover will be the next step but that will need to wait awhile. Just finished my basement and will soon being upgrading to a 9.2.6 layout. Need to build my surrounds and atmos first.

Have you gone active on your 4722s? I know many in the JBL thread are and some even copied the active settings from the crown amplifiers.
Yep. Long ago. Documented a bit here:


I'm using FIR filtering for a linear phase response and have my room correction baked in as well.

Response @ LP from the center. L/R are similar, but crossed at 650. Slightly different curve applied since then.

 

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Not to be off topic (too much), but that spl/phase plot is freaky! Is that measured in your room? That's what the digital crossover gets for you?

The phase is very interesting. What is the sonic benefit of keeping the phase constant? And just out of curiosity, why does the phase wrap when you get to the subwoofer; is it because it's ported? Sorry for the noob questions. I've heard of digital/active crossovers but not looked into it. Very interesting.
 

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Discussion Starter · #6 ·
Yep. Long ago. Documented a bit here:


I'm using FIR filtering for a linear phase response and have my room correction baked in as well.

Response @ LP from the center. L/R are similar, but crossed at 650. Slightly different curve applied since then.

Very very nice, so much great information in there! I think once I get bored/used to my new setup I'll start tinkering with active. I wired everything for this in the future.
 

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Discussion Starter · #7 ·
Not to be off topic (too much), but that spl/phase plot is freaky! Is that measured in your room? That's what the digital crossover gets for you?

The phase is very interesting. What is the sonic benefit of keeping the phase constant? And just out of curiosity, why does the phase wrap when you get to the subwoofer; is it because it's ported? Sorry for the noob questions. I've heard of digital/active crossovers but not looked into it. Very interesting.
Since the JBL 2384 + any large compatible format CD (2453h-sl & 2452h-sl) really is the star of this speaker and since this is a thread dedicated to DIY, I think anything related to building these speakers, including any tweaks or modification to the original design is more then welcomed! I encourage it! I think it would be great to have a list of diy 2384 related designs for anyone wanting to build speaker of this caliber.
 

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Not to be off topic (too much), but that spl/phase plot is freaky! Is that measured in your room? That's what the digital crossover gets for you?

The phase is very interesting. What is the sonic benefit of keeping the phase constant? And just out of curiosity, why does the phase wrap when you get to the subwoofer; is it because it's ported? Sorry for the noob questions. I've heard of digital/active crossovers but not looked into it. Very interesting.
I could keep the phase flat to lower frequency, but it introduces more delay. That's the downside of FIR filtering. As you don't really hear phase down that low, and I'm crossing above there, it doesn't really matter. Yes, the phase change is from the ported enclosure.

Benefits... It makes it easy to cross things over. Some say it improves the sound, but I haven't really heard it. Everything is just time aligned perfectly. That wasn't a measurement, but an estimate post-filter application. It just showed the curves and xover really clearly.

This is an actual measurement from around my lp of the l/r. Different curve applied, which has changed sinced. The HF has been lifted a bit since I haven't been listening as loud.

 

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Hey guys, what do you find with this cinema design with regards to how a voice stitches together given that the HF and LF sources are so far apart relative to your seating distance? In the distances in a cinema, they certainly sound as a point source. Does this not create a problem when so much closer at home?
 

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I could keep the phase flat to lower frequency, but it introduces more delay. That's the downside of FIR filtering. As you don't really hear phase down that low, and I'm crossing above there, it doesn't really matter. Yes, the phase change is from the ported enclosure.

Benefits... It makes it easy to cross things over. Some say it improves the sound, but I haven't really heard it. Everything is just time aligned perfectly. That wasn't a measurement, but an estimate post-filter application. It just showed the curves and xover really clearly.

This is an actual measurement from around my lp of the l/r. Different curve applied, which has changed sinced. The HF has been lifted a bit since I haven't been listening as loud.
Thanks @notnyt! Your spl/phase measurement is still amazing.

I've thought about the "constant phase". I definitely see where it would make the crossover between drivers easier to implement. It's always phase matched! Also, intuitively, I would think that it would be a benefit in how we hear the reproduction as well. Every frequency is time aligned (at least that's how I think of it). I just wonder how that sounds and if you can hear it, why wouldn't we have been doing it sooner. (I am assuming that it would be possible to maintain constant phase with a passive network - just a much more complicated crossover network).

Thanks for sharing. Interesting stuff.
 

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Discussion Starter · #11 ·
Hey guys, what do you find with this cinema design with regards to how a voice stitches together given that the HF and LF sources are so far apart relative to your seating distance? In the distances in a cinema, they certainly sound as a point source. Does this not create a problem when so much closer at home?
I sit 12ft from mine... I'd put them up against any speaker ever created honestly.
 

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I sit 12ft from mine... I'd put them up against any speaker ever created honestly.
Forgive me. I've jumped into the question without the proper terminology. I'll be back when I have that.
Okay, I'm back with the right terminology. The relationship of the distance between speaker drivers and the listening distance is important due to time alignment and phase from each to the listener. There is a listening distance for each size speaker where driver integration achieves coherence at the listening position. This is called driver integration distance. My point is that you can be too close to a large speaker with drivers far apart. Given these are not near-field or even mid-field speakers, I wondered what the integration distance is and whether you guys have experimented with that.
 

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Discussion Starter · #14 ·
These use either a 630hz active crossover and 800hz passive, at these frequencies your center to center wavelength is somewhere around 20-30". At these frequencies the woofers act like a single accoustic source so there shouldnt be too much lobing and I'm not seeing anything offensive in the measurements.
 

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These use either a 630hz active crossover and 800hz passive, at these frequencies your center to center wavelength is somewhere around 20-30". At these frequencies the woofers act like a single accoustic source so there shouldnt be too much lobing and I'm not seeing anything offensive in the measurements.
It's not lobing, it's just that if you're close, the distance from your ears to the lf center is different than the distance from your ears to the hf center.
 

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It's not lobing, it's just that if you're close, the distance from your ears to the lf center is different than the distance from your ears to the hf center.
Bullseye. I would think that this particular model is not problematic because the CD is quite low/close to the LF. There is a story told about a director who had huge 3-way cinema stacks done in his residential scale theater. They were very professionally installed by the studio guys. An A-list residential calibration team came in to calibrate, and the stacks were eventually abandoned due to their over-size and the mess caused when integration distance just didn't exist in that room.
 

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I'm thinking of building a 'cheap' version of these with the alibaba 2452h clones but it doesn't feel right for the waveguide to cost almost as much as the driver. Are there any knock-offs of the waveguide as well?

Also, would a JBL 265H-2 work for these? I couldn't find a 265h-sl anywhere and these seem good for the money.
 

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I'm thinking of building a 'cheap' version of these with the alibaba 2452h clones but it doesn't feel right for the waveguide to cost almost as much as the driver. Are there any knock-offs of the waveguide as well?

Also, would a JBL 265H-2 work for these? I couldn't find a 265h-sl anywhere and these seem good for the money.
There is no 265h-sl, there was a typo in some of their docs that called it something different like 26SH or something. The 265h-2 is the woofer in the 4722.

The 2452h clones have my interest. If someone wanted to send me one to test I would, but fairly certain anyone can do that pretty easily.
 

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That's great. If my calculations are correct it should only be about $700 for each speaker. And that is including an upgraded cd from what is in the stock design(as long as the clones don't suck that is). Making it much more affordable than I had expected. Excited to get started on these once I have some time on my hands.
 
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