2RCC with open back mids?

[Ed H]

I have been trying to squeeze 1" from the Statement center height, and the only way I could pull that off is to use 1/2" MDF for top/bottom, and angle the front baffle so I can fit an 11" baffle on a 10" tall enclosure. I'm sure that would violate some basic design rules... :cry:

OR, I can build the 2RCC and be done with it! But no, I have to go a step further. Has anyone built the 2RCC with open back mids, like the Statement center? That would be the best of both worlds for me. :W

I have 21" from wall to front baffle, that would give me 10" behind the speaker for the mids to to breathe. I know more is recommended, but I'm hoping that is enough. Thanks for any info / links you can provide.

Edit: I have to squeeze a 1/2" off the height of this design too, but can do so much easier than 1" off the Statement center..

[wkhanna]

I would not recommend angling the front baffle. It will screw up the time alignment and make a great speaker sound mediocre. The mids and low end will get smeared and the LF will sound mushy and lethargic.

I speak from hard-earned experience learned from trying it with the Natalie P’s. Once I adjusted the feet to make the front baffle to be perpendicular to the floor the improved sound quality was jaw dropping.

Angling the front baffle requires the crossover be redesigned if you want the same performance that the original design produced.

[Hdale85]

I agree with Bill completely, also making the mids open backed would require the same crossover redesign and I'm not sure there would be much of an improvement if any regardless.

[Mrpictureman]

I to wondered about the open back mids on the 2rcc. The full statements just have a slightly more crisp sound to them although it may just be the listening material in the center channel. I have been too busy working and listening to move the 2rcc to the side to do comparison testing. I looked at both crossover plans and realized that I do not have the expertise to redo the crossover but it would be interesting to compare open mids vs closed in the 2rcc

[Jed]

I say try the open back mids with the 2rcc. That's what DIY is all about. Use the mid tunnel length, if you can, from the towers. The crossovers aren't that different.

[Mrpictureman]

Jed, are you saying just keep the same crossover in the 2rcc get rid of the inner guts of the box and add the mid tunnels. That was my thought? Am I also understanding that you would widen the box to accomodate matching length mid tunnels as on the full size statements?

[Jed]

Jed, are you saying just keep the same crossover in the 2rcc get rid of the inner guts of the box and add the mid tunnels. That was my thought? Am I also understanding that you would widen the box to accomodate matching length mid tunnels as on the full size statements?

That's pretty much what I'm saying. Post up a drawing in this thread, and I'll take a look at it. Should work.... but as others mentioned it's untested so results may vary. However, since the 2rcc box for the woofer is sealed, it probably won't hurt much adding a bit more depth to make the correct tunnel length for the mids. Adding more volume for the woofers will just lower the overall box Q a little.

Jed

[Ed H]

I'm pretty sure FroDaddy said in another post that the woofer volumes would / should be a little larger anyways, but he could not do it in his specific application.

Edit - After doing some back of the napkin calculations, the woofer enclosure will be ~1.4 ft3 with the mid tunnels added (5"x5" internal each, sharing the internal wall between them).

After a quick look in WinISD, I am 90% sure I will port the woofer enclosure too, just like the Statement center, and tuned to ~35Hz.

Note this was using the shielded woofer (RS180S-8).

[Mrpictureman]

Ed I would love to hear how your results come out if you do go this way. I just don't have the time for another month or two but am very curious on the results?

[LSV8]

I have been trying to squeeze 1" from the Statement center height...

Why are you limited to 10"? Will this be placed inside a cabinet or entertainment center? If so, open back mids will not give the desired (or designed) effect.

Has anyone built the 2RCC with open back mids, like the Statement center? That would be the best of both worlds for me. :W

https://www.htguide.com/forum/showthread.php?t=36539

I built and tested an open back version for a short while. With the depth of the enclosure (16.5"), and the distance from the wall (18" sounded best)... the front of the speaker was nearly 3ft from my projection screen. The woman of the theater vetoed the design shortly after, and I went back to my original center til I find time to re-build. ops:

I have 21" from wall to front baffle, that would give me 10" behind the speaker for the mids to to breathe. I know more is recommended, but I'm hoping that is enough. Thanks for any info / links you can provide.

The 2RCC is 13.5" deep... if you have 21" baffle to wall, you'd have 7.5" of room. If using the full size Statements mid tunnel length (as recommended), the enclosure would be 16.5" deep... giving you 4.5" of room.

What is currently limiting you to 21"? Is this speaker mounted in a cabinet?

Edit - After doing some back of the napkin calculations, the woofer enclosure will be ~1.4 ft3 with the mid tunnels added (5"x5" internal each, sharing the internal wall between them).

Again, that seems a bit off. What tunnel length are you assuming for this change? The crossover is based on the original Statements, thus a 16.5" tunnel should be used. (As Jed suggested above.)
Calculations done here:

https://www.htguide.com/forum/showthread.php?t=36539

Note this was using the shielded woofer (RS180S-8).

The 2RCC uses the RS225... not the RS180. Using an RS180 would require a change in the crossover.

Note: I have disabled my photo-bucket account since posting pictures in the above mentioned thread. If you would like a picture of the drawing or the actual .dwg file with measurements, feel free to PM me with your email address.

[Ed H]

AH. Thank you for the multiple corrections. ops:

I thought the mid tunnels would be based off the Statement CC, not the full size Statements. If that is the case, this is a no-go. I was looking at the CC where the internal dims of the tunnels are 5 x 5 x 11.25.

I am limited to 21" distance wall to front baffle and 10" height because of an entertainment center. The front of the entertainment center is 21" from the wall. Note it is nothing but 3 glass shelves, open in the back and sides. I could pull it off the wall a couple inches, but not 1-ft!

My bad on the drivers too. I thought the Statement CC was based off the shielded woofer, not the RS225. Interesting Curt seems to think the RS180 or RS225 could work in the Statement line without crossover changes.. The Statement BOM on his site was updated 12/31/10 to use the RS180, and I don't believe the crossover changed.

[Jed]

There are 2 Statement CCs. One I designed for Frodaddy's specs and the original designed by Curt, which uses the RS180 driver.

[LSV8]

I thought the Statement CC was based off the shielded woofer, not the RS225. Interesting Curt seems to think the RS180 or RS225 could work in the Statement line without crossover changes.. The Statement BOM on his site was updated 12/31/10 to use the RS180, and I don't believe the crossover changed.

Sorry for the confusion... I'll try to break it down:

All of the Statement series is in fact based on the shielded RS drivers. Curt also does suggest the unshielded can be substituted for the original shielded drivers. However, the 180 should NOT be confused with the 225.

The RS225S, used in the full sized Statements, is an 8" woofer.

The RS180S, used in the Statement CC, is a 7" woofer.

RS= Reference Series. The number= Size (approx size in mm)

In all of the RS drivers, "S" as a suffix denotes being shielded. In other words, RS225 is an unshielded 8", and RS225S is a shielded 8". Same applies to the RS180, RS150, RS125, RS100, etc...

In my prior post, I simply dropped the "S" for the sake of conversation... I appologize if that added any confusion.

Jed's 2RCC uses the RS225S (8"), and is esentially a full sized Statement with slight changes made to the HP section of the XO. The 2RCC is more closely related to the full sized Statements than it is to the Statement CC.

[FroDaddy]

...
I built and tested an open back version for a short while. With the depth of the enclosure (16.5"), and the distance from the wall (18" sounded best)... the front of the speaker was nearly 3ft from my projection screen. The woman of the theater vetoed the design shortly after, and I went back to my original center til I find time to re-build. ops:

The 2RCC is 13.5" deep... if you have 21" baffle to wall, you'd have 7.5" of room. If using the full size Statements mid tunnel length (as recommended), the enclosure would be 16.5" deep... giving you 4.5" of room.

LSV8 and I spoke via PM about the tweeter notch on the mid-tunnel problem with an open backed 2rCC . He solved this issue and I have attached a graphic describing it.

[Ed H]

LSV8, I noticed you mentioned giving this a shot in the other thread. Have you made any progress?

[LSV8]

LSV8, I noticed you mentioned giving this a shot in the other thread. Have you made any progress?

Hey Ed,

What exactly are you referring to? Building an open back version?

If so... yes, I have built a working open back 2rCC. I'll quote again what I posted:

"I built and tested an open back version for a short while. With the depth of the enclosure (16.5"), and the distance from the wall (18" sounded best)... the front of the speaker was nearly 3ft from my projection screen. The woman of the theater vetoed the design shortly after, and I went back to my original center til I find time to re-build."

FroDaddy was kind enough to modify my original 2D drawing and add an explanation to the changes. It was essentially an original design 2rCC, same height and width, only 16.5" deep to accommodate the mid tunnels. You can see this drawing above. ^

We have also been speaking via PM about this recently, and he has come up with a few more tweaks to design the ultimate "Statement based" center! :twisted: I'll let him elaborate when he is ready.

[Jim Holtz]

I am limited to 21" distance wall to front baffle and 10" height because of an entertainment center. The front of the entertainment center is 21" from the wall. Note it is nothing but 3 glass shelves, open in the back and sides. I could pull it off the wall a couple inches, but not 1-ft!

Hi Ed,

Just a quick follow up to your comment about an entertainment center. To clarify, you can not use an open back center in an entertainment center. The rear wave has to be open around the speaker so it can be reflected forward and blend with the front wave of the speaker. They're really not very picky about placement but being open around the speaker is an absolute requirement.

I hope that makes sense...

Jim