Next project: 3-way with open baffle

[50 watt head]

Here is what I'm thinking for my next project:

Peerless 831735 woofer + Dayton RS52 mid + Vifa BC25SG tweeter

The woofer will be housed in a tuned enclosure, straightforward. The drawring I've attached is my idea (not sure where, but I must have seen some photos of an overall package like this before) of a midrange and tweeter on a free-standing baffle. My thinking (so far ) is along the lines of -- they don't need a box, so no real need to build one.

Motivation for this design: a three-way that is "just right" for my living room. I am [now!] very familiar with the Peerless 831735 and the Vifa tweeter, and how they work together in a 2-way that I'm very happy with. I'd like to see if I can improve things even more with a 3-way. This would also be somewhat modular, since I could conceivably place the MT baffle on a bigger bass bin in case my listening environment changes/grows.

The mids are on sale right now for $35.00 each + the Peerless are still available for $30.00 + the tweets are cheap at only $15.00 = Another affordable project for me

Does anyone have any concerns or worries about the way things look so far? Are there any potential dangers I may not be aware of? Thanks!

[Wolf]

Re: Next project: 3-way with open baffle

Yep- 1 concern. (IMO) Use a different mid, unless you don't want realism.

I would try the HiVi DMN-a, if it was me...

And you mentioned inspiration in seeing another like that, was it these?



Later,
Wolf

[Pete Schumacher]

Re: Next project: 3-way with open baffle

Great idea. Unlike Wolf, I (and a number of others) like the RS52, but you have to be careful not to cross it too low. Keep it to about 800Hz and you'll be treated to very clear upper mids.

But I'd opt for a smaller tweeter, like the ND28, or ND20FA or FB, so that you can get the acoustic centers a bit closer together.

And seeing that the 800Hz region was a problem area for that baffle shape, putting the XO in that range could give you more tuning options to dial it in.

Keep in mind that a smaller format mid will exacerbate baffle diffraction, especially above the step, where the RS52 will be playing. Pay special attention to that upper baffle, and get some large roundovers up there to smooth things out.

[CWH&R]

Re: Next project: 3-way with open baffle

Pete I think wolf is saying that the RS52 is no good for open back.

[Mark65]

Re: Next project: 3-way with open baffle

Actually, I don't believe that he is. He just doesn't care for that driver. I'm not it's biggest fan, either, but I don't see why it couldn't be used OB.


Mark

[50 watt head]

Re: Next project: 3-way with open baffle

Thanks for the comments and suggestions everyone, much appreciated!

[50 watt head]

Re: Next project: 3-way with open baffle

And you mentioned inspiration in seeing another like that, was it these?

Yep, I recall seeing that pic of yours before, so I'm sure they formed a part of my inspiration.

[rpb]

Re: Next project: 3-way with open baffle

Keep in mind that a smaller format mid will exacerbate baffle diffraction, especially above the step, where the RS52 will be playing. Pay special attention to that upper baffle, and get some large roundovers up there to smooth things out.

+1 .... I would attempt this only if you plan to measure the responses.

[Wolf]

Re: Next project: 3-way with open baffle

That's right- I don't like it, and never have, no matter who's used it.

In the way OP stated 'open-back', yes. Dipole- no.

Later,
Wolf

[50 watt head]

Re: Next project: 3-way with open baffle

OK, here is a preliminary stab at a crossover for

Peerless 831735 + HiVi DMNa + Vifa BC25SG15

I've mocked it up for now as a conventional box/baffle, with convenient/ballpark driver offsets, just to get the ball rolling.

Pete, I modeled around with the ND20, and I after awhile I just found the Vifa easier to work with. Even though it's a large-faceplate tweeter, that hasn't caused any trouble for me yet.

Wolf, thanks for the tip on the HiVi mid, so far that's been pretty easy to work with, and it came out with less components in the Xover than the tweeter

[greywarden]

Re: Next project: 3-way with open baffle

So... what's the benefit of an "open baffle" with sealed-back drivers on the baffle?

Are the woofers going to be open, too?

I was going to suggest using a cone did, like a small fullrange, and a tiny tweeter like the NDs

Then situate the peerless woofers in an H-, U-, or W-frame (for lack of a better term, I just woke up).

[50 watt head]

Re: Next project: 3-way with open baffle

So... what's the benefit of an "open baffle" with sealed-back drivers on the baffle?

I'm not sure there are any benefits. My considerations behind this idea were partly aesthetic ("it's cool and unique") and partly functional ("why build a box for drivers that are already sealed?").

Basically, I was planning to build a ported bass bin for the woofer; that's straightforward, nothing special there. Beyond that, the design process would involve nothing more than a simple baffle with the M and T drivers mounted to it. Play around with offsets and alignment from there. Sounds like fun!

[greywarden]

Re: Next project: 3-way with open baffle

Oh well yeah that makes sense

[50 watt head]

Re: Next project: 3-way with open baffle

Here's another simulation, using the RS180-8 instead of the 831735.

Crossover is very similar to the circuit I posted above. Looks like an increase of a few dB in sensitivity. The RS180 mounting hole is 5.75" which is identical to the 831735, so the cabinet could be built such that they are physically interchangeable.

[rpb]

Re: Next project: 3-way with open baffle

OK, here is a preliminary stab at a crossover for

Peerless 831735 + HiVi BMNa + Vifa BC25SG15

I've mocked it up for now as a conventional box/baffle, with convenient/ballpark driver offsets, just to get the ball rolling.

Pete, I modeled around with the ND20, and I after awhile I just found the Vifa easier to work with. Even though it's a large-faceplate tweeter, that hasn't caused any trouble for me yet.

Wolf, thanks for the tip on the HiVi mid, so far that's been pretty easy to work with, and it came out with less components in the Xover than the tweeter

Why do you place the resistor in front of the x-over? It will change other values needed, but I'd put a resistor in series, and one across the terminals.