Home/Pro 8" 2-way: RS28A and B&C 8BG51

[69FireBird]

Re: Home/Pro 8" 2-way: RS28A and B&C 8BG51

can you tell me who makes this front panel and how muc they cost? I tried searching this website and nothing shows up and I wouldlike to make these, why is it so hard to find this store that sell sthis speaker baffel?

[Pete Schumacher]

Re: Home/Pro 8" 2-way: RS28A and B&C 8BG51

can you tell me who makes this front panel and how muc they cost? I tried searching this website and nothing shows up and I wouldlike to make these, why is it so hard to find this store that sell sthis speaker baffel?

It's not a store 69Firebird. One of the members here made those for me on his CNC machine. Tom Jones (takitaj) who I mentioned in the very first post of this thread is the maker of the baffle.

I know he's been hard to reach by the members here recently, but hopefully after the holidays, he'll make an appearance again and perhaps a few of these baffles can get made.

I've sent Tom an email asking for the exact profile of the waveguide so that if he's unable to make them for whatever reason, we can get someone else to cut them for someone who wants to build this project.

Dave Pellegrene also makes waveguides that could be used instead of this baffle. It might take some modifications to the crossover if he doesn't get the exact profile match, but that could be a good option if Tom doesn't make himself more available. I'll see if I can get him on the phone tomorrow and see if he can make a few of those baffles, or at least send me a drawing of the waveguide cross section.

[BeeTL]

Re: Home/Pro 8" 2-way: RS28A and B&C 8BG51

The more I look, the more I realize the EOS-6 is the horn I'd like to use in my build.

If it can be made to work with either an RS28 or a compression driver, so much the better!!!

[Erich H]

Re: Home/Pro 8" 2-way: RS28A and B&C 8BG51

The EOS-6 was the main one I was working on just to keep the width under control. Going by the look of Pete's front baffle, I think both are very similar in shape and diameter. But the 1 piece baffle certain looks great.

[BeeTL]

Re: Home/Pro 8" 2-way: RS28A and B&C 8BG51

The EOS-6 was the main one I was working on just to keep the width under control. Going by the look of Pete's front baffle, I think both are very similar in shape and diameter. But the 1 piece baffle certain looks great.

Cosmetically, it really hits the mark for what I'm hoping to accomplish with the project I'm thinking through.

Do you expect to stock the DNA 360 for non-SEOS 12 builds?

How would you expect the DNA 205 compare to the 360 in this specific driver format?

I'm looking to do a small, highly-stylized multi-purpose cabinet targeted at musicians for studio-monitor and small room DJ/party use.

I'll probably do a matching sub-box if the concept gains any momentum.

[BeeTL]

Re: Home/Pro 8" 2-way: RS28A and B&C 8BG51

OK, I just thought of an elegantly simple solution to fitting the RS28 into a standard horn.

This solution assumes easy access to the rear of the baffle.

1. Mount the horn to a jig and cut off the rear mounting plate with a table saw.

2. Mount the RS28 to a DUMMY baffle that's just a bit bigger than the face of the horn.

3. Drill holes through the dummy baffle that match up to the horn's mounting holes.

4. Mount the horn to the front of the SPEAKER baffle using extra long bolts (3"-4") and locking nuts/washers.

5. Mount the RS28 dummy baffle to the bolts using locking nuts on both sides of the baffle. This ensures proper fit, alignment, and eliminate excess pressure against the dummy baffle.

Make sense?

[BeeTL]

Re: Home/Pro 8" 2-way: RS28A and B&C 8BG51

Another epiphany:

Isn't this the old MCM waveguide?

If so, why not just mod this for the project?

http://www.diysoundgroup.com/waveguides/dw-62s.html

[Pete Schumacher]

Re: Home/Pro 8" 2-way: RS28A and B&C 8BG51

While that waveguide can certainly be modified to accept the RS28, it won't have the same performance as the guide I've used in the Marksmen build. The 15dB of low end boost would probably be reduced to about 8dB, which would probably be on the low end of what's required to properly match the woofer. It would probably be better to just use a compression tweeter with that guide without any mods. Even then, unless the CD has a natural response that extends to 1KHz, that guide may not be enough.

[BeeTL]

Re: Home/Pro 8" 2-way: RS28A and B&C 8BG51

DoubleTap did a build with the RS28/MCM a while back and indicated it would be very comfortable at 1200Hz.

It looks like the 8BG51 can get there comfortably as well.

Am I on the mark or am I missing something completely?

[Erich H]

Re: Home/Pro 8" 2-way: RS28A and B&C 8BG51

Pete, I did some quick and dirty measurements on the RS28a in my basement. It would appear that I messed up on the tweeter by itself. I just had it mounted to a 16" x 16" sheet and aimed up from the floor. Not the greatest, so these graphs aren't going to be that good. Blue is the waveguide.

Either way, here's what I got:

The EOS-6 is only about 1.75" or so deep after the back is lopped off.




This is with the EOS-8. The throat needs to be shortened.



SEOS-10:



SEOS-12

[Pete Schumacher]

Re: Home/Pro 8" 2-way: RS28A and B&C 8BG51

DoubleTap did a build with the RS28/MCM a while back and indicated it would be very comfortable at 1200Hz.

It looks like the 8BG51 can get there comfortably as well.

Am I on the mark or am I missing something completely?

1200Hz is about it for what I'd consider a good XO point for the woofer. It all comes down to what kind of boost the guide gives the tweeter down low. That will have a dramatic effect on what kind of power levels you can expect to send to the RS28. For home use, it's probably just fine. But the modifications required to make the guide work with the tweeter make the option of a CNC cut baffle even more attractive.

[Pete Schumacher]

Re: Home/Pro 8" 2-way: RS28A and B&C 8BG51

Pete, I did some quick and dirty measurements on the RS28a in my basement. It would appear that I messed up on the tweeter by itself. I just had it mounted to a 16" x 16" sheet and aimed up from the floor. Not the greatest, so these graphs aren't going to be that good. Blue is the waveguide.

Either way, here's what I got:

The EOS-6 is only about 1.75" or so deep after the back is lopped off.

[ATTACH=CONFIG]42781[/ATTACH]


This is with the EOS-8. The throat needs to be shortened.

[ATTACH=CONFIG]42782[/ATTACH]

SEOS-10:

[ATTACH=CONFIG]42783[/ATTACH]

SEOS-12

[ATTACH=CONFIG]42784[/ATTACH]

thanks for posting that. Even the EOS6 looks quite workable, but I really like the 10 and 12. What are the chances of offering those guides custom fit for the RS28?

[Erich H]

Re: Home/Pro 8" 2-way: RS28A and B&C 8BG51

The 10 and 12 do look nice. But if they're put above an 8" woofer, they appear a bit too big. I already have a baffle cut for the SEOS-10 over the 8" B&C and will show you what I mean later if I get time to take a photo.

I could probably make that EOS-6 and certainly the EOS-8 test a bit flatter if you think those are better options for smaller speakers. I might have taken off a bit too much throat on the EOS-6.

If demand was not big, I could make the larger SEOS models myself. The smaller ones would likely have higher demand and it might make sense to actually get them produced in higher volumes. I could see them being used with smaller woofers quite a bit.

[BeeTL]

Re: Home/Pro 8" 2-way: RS28A and B&C 8BG51

Erich,

Will the EOS-6 cross nicely at 1kHz to1.2kHz with nay of the horns you offer?

Also, will the DNA 360 be available for non-SEOS-12 builds?

THANKS!!!

[cjd]

Re: Home/Pro 8" 2-way: RS28A and B&C 8BG51

Erich,

Will the EOS-6 cross nicely at 1kHz to1.2kHz with nay of the horns you offer?

Also, will the DNA 360 be available for non-SEOS-12 builds?

THANKS!!!

You can force a crossover at any point you think reasonable, but you're not getting the same boost at that frequency. The RS28A has been crossed at 1k (I think? Or was it 1.2?) without a waveguide, but it's tricky to get right. It also depends on the mid-woofer - not all 8" can cross that high, or need extra care to do so.

That said, I don't quite understand your question. You want to know if a horn will cross with a horn? It's about the tweeter you use IN the horn, and you'll get less low end the smaller the waveguide/horn.