Mounting an RD50

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My impulse purchase BG RD50s arrived today. I was surprised by how much they weigh, and by how they are not as tall as I was expecting.

Anyway, I'm trying to work out the best way of mounting them. Initially I'll test them baffleless like StigErik crossed to the H-frame subs from my digiOrions.

The weight makes my thought of a simple folded perspex baffle like my bedroom dipoles seem dangerous.

So assuming I need a baffle, do people mount them from the front or from the rear?

Mine are used and didn't come with any kind of gasket, but the various knobs and stickie out bits on front and back are already as annoying as the ones on my Neo10s and 3s.

Why don't BG give us a nice flat surface?
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I'm doing some experiments with a baffle for my RD-75's. I have hung the RD-75 from the ceiling as before, and just attached two boards, one on each side, and on the front side of the driver, making the baffles flush with the front of the driver. Very simple.
I have a warehouse type room so could hang them from the beams. I even have pulleys already. But the ceilings are very high. Aesthetics are kind of important and dangling them low enough to be at floor height will look a bit odd and possibly interfere with the screen.

Are your boards flush with the edges, or flush with the central section?

How wide is the baffle? Given your success naked, I'm a little surprised. Although given our terrible desire to fiddle I guess I shouldn't be. I now have my digiOrions, Plutos, a pair of Duevel omnis, a narrow baffle 4 way OB prototype using Neo10s and Neo 3, a wider baffle of the above with drivers arranged horizontally and my simple two way perspex OBs all splayed around the room.

Plus I'm considering pouncing on some cheap HiVi M8s for mids to go with the RD50s, although the reason for getting them in the first place was to have a simple system like yours.

Oh, and pair of Apogee Duetta Signatures are on the way.

My lovely partner has gone from enjoying my massive downstairs lair to hating it as speakers expand to fill the available space.


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My boards are flush with the central section of the driver. They are 20 cm wide each.

This is just an experiment I'm doing, have not decided whether I like it or not. Frequency response and polar pattern is much worse than the naked driver, but the low-end efficiency is increased by 10 dB. This would lead to less distortion.
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This is how my wide baffle experiment looks like, and the EQ curve. There is a deep notch around 1 kHz which is caused by the baffle. It moves in frequency with changed baffle width.


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BG recommends a 12" wide baffle as a minimum.

I am using a pair of RD75s hanging bare except for some pipe insulation, crossed over at 280Hz to 4 15" woofers per side mounted on 24" wide baffles. They sound great.

I think you would want to mount them from the rear, though just attaching some panels on each side as StigErik has done makes sense given the long cutout needed in any one-piece baffle. Some foam weatherstripping should seal the gaps.

Mine sound so good it is tough to get motivated to experiment. I was at CES and listened to some ridiculously expensive speakers and didn't hear anything clearly better. I'll be curious to hear your thoughts.
Sorry to reply to my own post, but I can't find the edit button.

I've done extensive listening and quick and dirty measurements. It seems the RD50 isn't as suited as the RD75 to the kind of setup StigErik and gworrel are enjoying.

The issue isn't so much the FR. I've been able to EQ the RD50/H-frame combo flat fairly easily. Flatter than my Orions.

The problem is that the response varies significantly with slight changes in distance and vertical listening position. Lean forward and they are lively. Lean back and they are mellow.

No doubt a large part is because I sit much farther back (4.5m) than StigErik's nearfield position, and the line is not as tall. Plus the bass is a dipole point source whilst the mids and up are a line source and hence have different radiation patterns.

But given one of main reasons I'm trying this is to get consistent response whether I sit up or flop down the results are not encouraging.

As mentioned above, a line of bass/mids would probably help. As would using RD75s instead of RD50s.

But so far the experiments isn't a success.
that's the reason why I haven't pulled the trigger yet. Line sources shift image size depending on distance, so you have to choose your spot. Shame as the RD serie does sound very clean. How does the Neo 10/3 combo perform vs the Orion? I guess you can always try with the Excel medium and cross around 500hz..
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I've experimented a little with the wide baffle I showed a few posts ago. The only advantage is better efficiency below 1 kHz. The rest is simply worse; frequency response, off-axis response, impulse response and sound quality.

In my opinion you get the best from a RD75 as a nude dipole with rounded edges only. And it should be listened to in the near field.
That is interesting. Did you experiment at all with different width baffles?

I have been considering some changes to my setup. I bought 16 Dayton Audio RS-225s to use as a midbass on an open baffle (8 per side) next to the RD-75. I have been considering buying a large number of the tweeters used in Don Keele's constant beamwidth array to use as a tweeter array on the high end. CBT36 Line Array Speaker Kit Pair 301-980

The tweeter is here: 1/2" Dome Tweeter Element 10 Pcs. 275-010

I was considering putting 8 RS-225s, the RD75, and 84 1/2" inverted dome tweeters on a single baffle of perhaps 24" width (61cm).

Playing around with the EDGE program seems to produce the smoothest response with a very narrow baffle. One alternative could be a baffle with a very large roundover which also seems to produce a smooth response.

My listening position is about 3.5 meters away. I have a second row which is at about 5.5 meters. I find the highs definitely drop off when out of the sweet spot. I use the system for both music and home theater and want to accommodate guests even though most of the listening is done solo.

Using the 8" midwoofers will allow me to use my 15" TC Sounds woofers as subwoofers and raise the crossover frequency to the RD75. I am hopeful that the array of tweeters will give better response throughout the room in the high frequencies. The price is right on the tweeters but I am a little uncertain because the tweeters are not dipole so I will lose that aspect of the RD-75 above the crossover frequency to the tweeters. Not sure if that matters.
I was not really happy with the sound of the RD75s until I dialed in a decidedly non-flat response curve. Similar to what they discuss here: House curve: What it is, why you need it, how to do it! - Home Theater Forum and Systems -

I use a DBX driverack PA for EQ. I am sure the full height bass array I am using helps. The rd75 is also full height floor to ceiling in my room. It sounds so good I am almost afraid to change it. Of course StigErik's bass setup is the stuff of legends.

It would be interesting to compare to the Orions. I think that once you get to a certain level of quality, details of EQ and the room can make a huge difference. I am sure it is partially a placebo sense that bigger is better, but it is hard for me to imagine a small system like the Orion sounding as good as these 6 foot tall monstrosities.

I would like to make surround speakers with the neo series. To keep the cost down, I was considering perhaps a neo8 paired with an rs225 using the minidsp as crossover.
I am experimenting with waveguides for Neo3.
It makes a huge difference (better).
Next I will try attaching cylinders on each side.
I have 2" diameter pipe isolation and 3" poster tubes to try.
Someone who has the drivers should try a 4-5" cylindrical baffle on each side of RDs.
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