JBL 4647a Bass Cabinets

[TubeHiFiNut]

Both of my JBL 4647a Bass Cabinets have arrived. Still need to get them unboxed. They will be set up in my room in place of the Belles.

Here is an Internet pic:



There is a JBL 2226h in one cabinet. The other is empty. I have a second 2226h on the way.

In the interim, I'll install my Eminence Kappa 15a woofers in there to see how they sound.

These bass cabinets will give me the flexibility to try a variety of horns in a two-way configuration using a crossover frequency in the 1200hz to 1800hz range.

I'll post the various configurations and listening impressions to this thread.

 

[TubeHiFiNut]

The horns I'll be trying will include:

Emilar EH-500-2
Emilar EH-520
Altec 32B
Community SRH-90
"No Name" ABS bi-radial
"No Name" ABS 11"x17" long throw
Renkus-Heinz SSH-800

The drivers will include:

Renkus-Heinz SSD-3301-16 (2")
Renkus-Heinz SSD-1800-8 (1")
Altec 807-8 (1")
Klipsch K55 (1" screw mount)

Crossovers will include:

Renkus-Heinz 1800hz
Altec 500hz (only on the horns capably of 500hz response)
DIY 1200hz 1st order, oil caps
Might try some more complex DIY offerings. Been looking at the crossovers @je2a3 is using on his 2-way Altecs.

More to follow.

 

[je2a3]

Some nice horns and drivers there that I am quite familiar with. However, I have no experience with any of the woofers. The Altec 414 became the mainstay of my 2-way project because of its fine midrange performance. The horn/compression driver combo is just there to augment the higher frequencies which are basically harmonic overtones, about 3 octaves.

I suggest listening to the JBL 2226H and Eminence Kappa 15A as full range drivers first to get to know their nature. Back in the late 90s, I chose the Altec 414A over the 416A because of peaks in the upper midrange of the 416A. I accepted the compromise of less bass for better midrange. Of course the raggedness can be mitigated by using a more complicated crossover, EQ or both, but I wanted to use the simplest crossover/EQ I can DIY.

Hope this helps and happy listening/tinkering!

JE

 

[TubeHiFiNut]

Some nice horns and drivers there that I am quite familiar with. However, I have no experience with any of the woofers. The Altec 414 became the mainstay of my 2-way project because of its fine midrange performance. The horn/compression driver combo is just there to augment the higher frequencies which are basically harmonic overtones, about 3 octaves.

I suggest listening to the JBL 2226H and Eminence Kappa 15A as full range drivers first to get to know their nature. Back in the late 90s, I chose the Altec 414A over the 416A because of peaks in the upper midrange of the 416A. I accepted the compromise of less bass for better midrange. Of course the raggedness can be mitigated by using a more complicated crossover, EQ or both, but I wanted to use the simplest crossover/EQ I can DIY.

Hope this helps and happy listening/tinkering!

JE

Thank you, @je2a3

Listening to the JBL and Eminence woofers full range to assess their midrange performance is an excellent idea!

 

[billfort]

Great post JE, thanks for that! Listening to the woofers straight up makes all kinds of sense before messing with the horns, especially since I think David is shooting for crossover up around 1200Hz or more and maybe simple first-order - they will be a big factor right on through the midrange.

The few woofers I kept around for a rainy-day are Altec 416A s and JBL 2205a s and it certainly wasn't about the lower bass, it was all about how they sounded to me in the upper-bass up into the midrange, but I never listened to them much full-range - I really should!

David, you are making me think about dusting off my old Altec 288-16b s, or maybe the 902-8b s, maybe some of those round ABS or fiberglass tractrix horns that seem all over the place now, maybe those wood Altec sectional repros Anthony was going on about...

I better stop.

 

[TubeHiFiNut]

Great post JE, thanks for that! Listening to the woofers straight up makes all kinds of sense before messing with the horns, especially since I think David is shooting for crossover up around 1200Hz or more and maybe simple first-order - they will be a big factor right on through the midrange.

The few woofers I kept around for a rainy-day are Altec 416A s and JBL 2205a s and it certainly wasn't about the lower bass, it was all about how they sounded to me in the upper-bass up into the midrange, but I never listened to them much full-range - I really should!

David, you are making me think about dusting off my old Altec 288-16b s, or maybe the 902-8b s, maybe some of those round ABS or fiberglass tractrix horns that seem all over the place now, maybe those wood Altec sectional repros Anthony was going on about...

I better stop.

Welcome back to the "Dark Side".

It won't hurt a bit.

 

[billfort]

As I mentioned in our phone conversation David, it might be good to check out the Hiraga Altec A5 crossover design that was covered in Sound Practices Issue-11 (both 8 & 16ohm versions were shown). IMO, the key piece to those circuits (and the Markwart crossover I use) is the 'EQ' padding circuit on the horn that features slow (6dB/octave) cap by-passing of the padding circuit as frequency increases; knocks down the horn shout in the mids and extends the highs. Of coarse the effectiveness and 'sound' of these would all come down to drivers, horn, cabinet and execution but the concept is a sound one in my experience.

Great article on this (and a fantastic blog all-around!) as applied to the A5 over at Jeff's Place.

 

[TubeHiFiNut]

As I mentioned in our phone conversation David, it might be good to check out the Hiraga Altec A5 crossover design that was covered in Sound Practices Issue-11 (both 8 & 16ohm versions were shown). IMO, the key piece to those circuits (and the Markwart crossover I use) is the 'EQ' padding circuit on the horn that features slow (6dB/octave) cap by-passing of the padding circuit as frequency increases; knocks down the horn shout in the mids and extends the highs. Of coarse the effectiveness and 'sound' of these would all come down to drivers, horn, cabinet and execution but the concept is a sound one in my experience.

Great article on this (and a fantastic blog all-around!) as applied to the A5 over at Jeff's Place.

Thank you, Bill.

I will definitely check this crossover out.

 

[Try1256]

Interesting choice of l.f. Cabinets. Will definitely sound different than folded horns.

 

[TubeHiFiNut]

Interesting choice of l.f. Cabinets. Will definitely sound different than folded horns.

Yes they should.

The bass horns in the Belles (or La Scalas) require a crossover in the 500hz range.

Two of the horns I want to try (Altec 32B and Renkus-Heinz SSH-800) are 800hz horns.

From what I have read, 1200hz seems to be a very workable crossover point for all of these horns, the 800hz and 500hz horns. The JBL bass cabs with either the JBL 2226H or Eminence Kappa 15A are good into the 2khz plus range so I should be OK.

 

[Audionut]

Lovely, another rabbit hole! Actually really looking forward to what you land on.

 

[TubeHiFiNut]

Lovely, another rabbit hole! Actually really looking forward to what you land on.

I think that this will be a fun "rabbit hole"

The goal is to find the best combination of horn-driver-crossover-woofer/enclosure using the components that I currently have available.

I am confident that, with sufficient experimentation and observation, the result will be something truly special.

In case you can't tell, I'm really jazzed about the opportunity to dive in to this process.

 

[Audionut]

I’m a little bit squarell-y so fighting the urge to follow suit. I’ll have to live vicariously thru you on this one. Keep the updates coming!

 

[rogerfederer]

 

[TubeHiFiNut]

I'm hoping to get the Eminence Kappa 15A woofers in there this weekend.

We did our monthly Computers for Kids Program this morning (gave 20 computers away to some wonderful, and very deserving, young people) so that pretty much did me in for today.

Might start later tonight and finish getting things set up tomorrow.

My friend who will be building the crossovers might have a line on some if the old PCB filled oil caps. That would be cool. If not, we'll use what's available.

To start, I'll use the 1800hz Renkus-Heinz crossovers.

Can't wait.....I feel like I did when I first got into this wonderful hobby.....just older, less energy and more aches and pains (especially from schlepping computers around all morning ).

 

[Punker X]

Watching with interest... seen these cabinets many times and thought they would make a base for two way projects.

 

[TubeHiFiNut]

Had breakfast with my Son this morning and then spent the afternoon schlepping stuff around so I can get the Belles out and the 4647s in.

Going to have to attach a piece of wood with 5-way binding posts to cover the opening in the back of the enclosure that I had shipped in since someone was kind enough to have removed the stock speaker terminations and what they were attached to. Minor speed bump.

Will work for a bit longer this afternoon and then pick up when I get home from work on Monday.

 

[TubeHiFiNut]

JBL 2226H is on the way.

Might just wait 'til it gets here as the other cabinet already has a 2226H mounted.

First order crossovers - 1200hz, 6db/octave, oil caps - just about done.

Still have to rearrange some stuff so I can schlepp the Belles out of the way.