Mirrored B460s with custom slope-fronted 4345-ish tops (notional)

[grumpy]

Anyone ever pondered something like this vs the std gorilla coffins?
(think we're out of monkey coffin territory at this size)

I'd be biamping anyway... easier to move around, and I like the modular concept.

Mostly curious about 4345 vs B460 bass sound quality (big cab vs eq'd alignment).
Experienced opinions encouraged. I have the theater 4645 18" boxes that have had both
2245 and 2242s in them, but have not heard B460(s) -or- 4345s (e.g., used higher than the
80Hz or so I've run the 4645s at).

Tops can go with newer 12" (1200) or stock 10" (2122), 2"-exit CD+short horn+lens, ring radiator top (2403/4/5)
(haven't yet heard Todd's 2402 lenses, but I have some 2402-5's somewhere also). 1st cut will likely adhere
to stock(ish) 4345 complement.

[Cyclotronguy]

Frequently and with fondness!

[BMWCCA]

Mostly curious about 4345 vs B460 bass sound quality (big cab vs eq'd alignment).
Experienced opinions encouraged. I have the theater 4645 18" boxes that have had both
2245 and 2242s in them, but have not heard B460(s) -or- 4345s (e.g., used higher than the
80Hz or so I've run the 4645s at).
Not sure I understood your comment. Of course you already know the 2245 in the 4345 is crossed at 290Hz. :dont-know:

My 4345s provide prodigious amounts of bass—in my house, in my room.

[JeffW]

There was a build of DIY mirrored B460s here not all that long ago, can'the recall the builder at the moment.

[grumpy]

Sorry, tried to stuff too much info into a small space. Appreciate the responses.

As I'd be bi-amping, was interested in 2245 alignments in 8ft3 (B460 type volume)
-and- running up to ~300Hz... deviating from 4345 further (seems it had been suggested
that one could also go with an expanded volume box, ... perhaps not quite the 12ft3
monster from the 1983 DIY article).

Should be able to experiment/compare w/ old 4645 (3-port to play with) units and 5235
in bump mode before ruining good wood :)

edit: thanks JeffW... the noted article had indeed provided useful info and motivation!

[rusty jefferson]

......Mostly curious about 4345 vs B460 bass sound quality (big cab vs eq'd alignment).
Experienced opinions encouraged. I have the theater 4645 18" boxes that have had both
2245 and 2242s in them, but have not heard B460(s) -or- 4345s (e.g., used higher than the
80Hz or so I've run the 4645s at).

Tops can go with newer 12" (1200) or stock 10" (2122).......

I use the 8 cubic foot 2245 (B460 clone) boxes from the GT diy article you mentioned, with a BX63A for the eq bump. I have listened to (but not lived with) 4345s. Not flaming the 4345 here, but my feeling right from the get-go was the 2245 runs up too high @ 290hz. Just my opinion. I suppose I'm saying I prefer the 2245 as a sub woofer. Since you're experimenting, perhaps the 12" woofers you mentioned (or maybe 15" E-145s?) could be used for mid-bass duty, and crossed over lower than the original 4345.

[JeffW]

I kinda wanted to try a 2245/2206/4" CD /tweeter if needed set up at one time. Like 4350-ish but an 18" vs two 15s.

[grumpy]

Glad to have the inputs, thanks.
Makes me happier with the modular decision :)

[RedCoat23]

There was a build of DIY mirrored B460s here not all that long ago, can'the recall the builder at the moment.

It was mine Jeff,

Called B460 The Twins (http://www.audioheritage.org/vbulletin/showthread.php?36208-B460-The-Twins)

[ivica]

I kinda wanted to try a 2245/2206/4" CD /tweeter if needed set up at one time.
Like 4350-ish but an 18" vs two 15s.

Hi JeffW,

Have You any "results", my interest is in that "way" ?


Regards
Ivica

[JeffW]

Hi JeffW,

Have You any "results", my interest is in that "way" ?


Regards
Ivica

No, never pursued it.

[JeffW]

It was mine Jeff,

Called B460 The Twins (http://www.audioheritage.org/vbulletin/showthread.php?36208-B460-The-Twins)

Thanks for the memory jog!

[gasfan]

I kinda wanted to try a 2245/2206/4" CD /tweeter if needed set up at one time. Like 4350-ish but an 18" vs two 15s.
You mean like this? I'm on it! :)


73971

[JeffW]

Party on! I was planning on a newer waveguide, but that's right in the ballpark :rockon2:

[grumpy]

Fun set of raw drivers! :)

Matching horizontal polars and sensitivity might be easier w/ another 2206 pair (?splayed or vertical)
just thinking out loud... If multi-amping and ultimate volume isn't key, then just matching polars would still help. I do wonder how well the funky "broken dome"-looking physical modifiers work... as seen on recent portable jbl pa boxes, or if better left to non-critical listening applications.

[ivica]

Fun set of raw drivers! :)

Matching horizontal polars and sensitivity might be easier w/ another 2206 pair (?splayed or vertical)
just thinking out loud... If multi-amping and ultimate volume isn't key, then just matching polars would still help. I do wonder how well the funky "broken dome"-looking physical modifiers work... as seen on recent portable jbl pa boxes, or if better left to non-critical listening applications.

Hi grumpy,

What kind of "problem" can be expected in the mentioned drivers combination?

Regards
Ivica

[gasfan]

Fun set of raw drivers! :)

Matching horizontal polars and sensitivity might be easier w/ another 2206 pair (?splayed or vertical)
just thinking out loud... If multi-amping and ultimate volume isn't key, then just matching polars would still help. I do wonder how well the funky "broken dome"-looking physical modifiers work... as seen on recent portable jbl pa boxes, or if better left to non-critical listening applications.

I was going to build it like a 4345 direct to a Driverack 4820. 4 stereo amps.

[gasfan]

Anyone ever pondered something like this vs the std gorilla coffins?
(think we're out of monkey coffin territory at this size)

I'd be biamping anyway... easier to move around, and I like the modular concept.

Mostly curious about 4345 vs B460 bass sound quality (big cab vs eq'd alignment).
Experienced opinions encouraged. I have the theater 4645 18" boxes that have had both
2245 and 2242s in them, but have not heard B460(s) -or- 4345s (e.g., used higher than the
80Hz or so I've run the 4645s at).

Tops can go with newer 12" (1200) or stock 10" (2122), 2"-exit CD+short horn+lens, ring radiator top (2403/4/5)
(haven't yet heard Todd's 2402 lenses, but I have some 2402-5's somewhere also). 1st cut will likely adhere
to stock(ish) 4345 complement.

Hey, just noticed your thread starter. I too want to build in modular format to make it easier to move around. I also have a pair of 4645C with 2242 to experiment with and a few pairs of 2245 on hand. A pair of 2206 would fit neatly on top in a horizontal arrangement with the 2390 above that. 2405 on top.

But what purpose does running the 18s above 80hz serve? I was thinking on cutting them off at 60 and the 2206 at 800.

[grumpy]

But what purpose does running the 18s above 80hz serve? I was thinking on cutting them off at 60 and the 2206 at 800.


Less of an issue with a beefy 12". With 10" mid drivers, it's a different story.
I'm considering both options.

[grumpy]

What kind of "problem" can be expected in the mentioned drivers combination?

Well... mismatched sensitivity and directivity characteristics were what I mentioned.
These are nothing new or completely insurmountable... more design/use considerations than problems.

My pondering was mostly in regard to matching the 2206 to the mid horn/lens horizontal dispersion
as that area (for me) is as critical as overall frequency response. If that doesn't work, adding boom and tizz won't fix it :)

[gasfan]

Well... mismatched sensitivity and directivity characteristics were what I mentioned.
These are nothing new or completely insurmountable... more design/use considerations than problems.

My pondering was mostly in regard to matching the 2206 to the mid horn/lens horizontal dispersion
as that area (for me) is as critical as overall frequency response. If that doesn't work, adding boom and tizz won't fix it :)

When you mentioned 'splayed', how far back from 0deg. were you thinking? Or forward? The 2310 can also be enclosed(tailored to match)a single 2206?

Ian advised in an old thread I started for this purpose that 10.3 net @27.2 Fb is optimal for the 2245.

[grumpy]

When you mentioned 'splayed', how far back from 0deg. were you thinking? Or forward? The 2310 can also be enclosed(tailored to match)a single 2206?

Ian advised in an old thread I started for this purpose that 10.3 net @27.2 Fb is optimal for the 2245.

Don't let me get you too spun up about this. The 2310 polars are published and 12" driver numbers can be calculated or measured. Just saying it's worth comparing at the intended crossover freq. One of -many- design considerations and choices.

(Skip the top part...)
http://www.acousticfrontiers.com/20131129controlled-directivity-speakers-open-up-your-acoustic-treatment-options/

thanks for the reminder on where that expanded 2245 vol notion came from! Too much history here to remember :)

[gasfan]

Don't let me get you too spun up about this. The 2310 polars are published and 12" driver numbers can be calculated or measured. Just saying it's worth comparing at the intended crossover freq. One of -many- design considerations and choices.

(Skip the top part...)
http://www.acousticfrontiers.com/20131129controlled-directivity-speakers-open-up-your-acoustic-treatment-options/

thanks for the reminder on where that expanded 2245 vol notion came from! Too much history here to remember :)

Thanks for the link. I did find Mr. Geddes' white paper also. I do find the idea of dual 2206s intriguing. I hope this doesn't turn into a retirement project. I'll be 60 in January. I've tried to farm out the cabs to three builders so far. Looks like I'm gonna have to clear some space and set up shop.

[JeffW]

That's why I thought maybe use a PT-F95HF or something like that. It'd be close to the dispersion of a 12" driver in that crossover region and not too much larger footprint on the baffle.

[gasfan]

That's why I thought maybe use a PT-F95HF or something like that. It'd be close to the dispersion of a 12" driver in that crossover region and not too much larger footprint on the baffle.

I love how those 2310 lenses look.:)

[ivica]

Well... mismatched sensitivity and directivity characteristics were what I mentioned.
These are nothing new or completely insurmountable... more design/use considerations than problems.

My pondering was mostly in regard to matching the 2206 to the mid horn/lens horizontal dispersion
as that area (for me) is as critical as overall frequency response. If that doesn't work, adding boom and tizz won't fix it :)

HI Grumpy,

From Your post (year 2007)
http://www.lansingheritage.org/images/jbl/specs/pro-comp/horns-lens/page3.jpg
IT can be seen that 2309&2310 as 2390 have over +/-50 deg. Off axis dispersion in the horizontal plane, so I can guess that 2206, as 12inch diver would reach +/-45 deg round 1200Hz, so the differences in the horizontal plane would not too different if crossover would not be over 1200Hz.
Speaking about the sensitivity, 2206 relative to 2245 is different story.using 2202 would make that easier.

Regards
Ivica

[gasfan]

HI Grumpy,

From Your post (year 2007)
http://www.lansingheritage.org/images/jbl/specs/pro-comp/horns-lens/page3.jpg
IT can be seen that 2309&2310 as 2390 have over +/-50 deg. Off axis dispersion in the horizontal plane, so I can guess that 2206, as 12inch diver would reach +/-45 deg round 1200Hz, so the differences in the horizontal plane would not too different if crossover would not be over 1200Hz.
Speaking about the sensitivity, 2206 relative to 2245 is different story.using 2202 would make that easier.

Regards
Ivica

Are the 2245 and 2206 not the same sensitivity? I thought they were both 95db.

[ivica]

Are the 2245 and 2206 not the same sensitivity? I thought they were both 95db.

Hi gasfan,
If mounting them in a large wall then you are right, but using them in the room, walls and flor would enhance LF region more then ,may be 6 dB,....so I can imagine that over 100dB LF section efficiently would be expected.

Regards
Ivica

[gasfan]

Hi gasfan,
If mounting them in a large wall then you are right, but using them in the room, walls and flor would enhance LF region more then ,may be 6 dB,....so I can imagine that over 100dB LF section efficiently would be expected.

Regards
Ivica

Okay, but I would remedy that with eq, no? Btw, where could I find info on dispersion specs for 2206? Or is this general characteristics dependent on cone size? In any case, do you know of a source?

[grumpy]

http://www.audioheritage.org/vbulletin/showthread.php?35887-What-s-so-special-about-the-Augsburger-mastering-monitor&p=363842&viewfull=1#post363842

[gasfan]

http://www.audioheritage.org/vbulletin/showthread.php?35887-What-s-so-special-about-the-Augsburger-mastering-monitor&p=363842&viewfull=1#post363842

Thank you Grumpy, but Pos does not provide a link.

Found it: http://www.audioheritage.org/vbulletin/showthread.php?22980-Near-or-Midfield-Question

Weird- I found it on Google but here it comes up error
(http://www.heritage.org/vbulletin/showthread.php?22980-Near-or-Midfield-Question)

[grumpy]

link? This is the simulation (done by others) I was trying to point to:

74007

which (as has been noted) might suggest a crossover frequency <1.2KHz ... perhaps quite a bit less
if attempting to match up with a wide angle horn. Perhaps more like 700Hz (or so).

(although the 4430 does OK with a 15" driver and ~1KHz crossover matching
up to a 100deg horn... so this is all "guidelines")


might want to edit your "found it" link to point to audioheritage.org vs heritage.org :)

[gasfan]

Didn't help. Doesn't matter now. Looks good. Cross the 2206/2441 at said fr. I like it. That's the cab vol. Pos pointed to in that old thread of mine.