BG RD50 useable frequency range?

[thylantyr]

Specs aside, what is real useable operating range for
the RD50's? Do they generate satifactory SPL down to 125hz? Is the roll off on the top end annoying?

Someone in cyber wants build a line array with RD50
mated to 6" midranges because they got the parts used
and highly discounted. I'm sure it can be made to work
but is the RD better without the midranges or can the
midrange be installed and just crossover the RD's around
1khz or so. If you do cross higher, the power handling
rises correct?

I've never used BG drivers before, what be the skinnay?

[JonMarsh]

Even the larger RD75 seems to sound happiest with a crossover point that's higher than many use; 600Hz at 4th order works well.

I'm going to take my RD50's down to 450-500 nominal, but with one of my cauer-elliptic filters.

Just think about the diaphram area re operating at lower frequencies...

Keep in mind, when Thomas and I mess around with the RD series drivers, we're looking for a system with low distortion to 100 dB+. But, aside from the lack of ease if you cross them lower, they also have a nasty habit of developing cracks and failures in the conductive coating.

Running them up top by themselves will produce reasonable results up to 16-18kHz on axis, but not much dispersion. The cavity resonance in the front is where you have to put in a notch filter, and above that frequency dispersion is narrow. My preference is to cross them over below the resonance to a true ribbon line array- that's why I've got a box of 16 JP2 Fountek's for the finished version of the Saint Saens.

Below the RD50, I plan to run a line array- since the RS subs seem to be turning out as well as the early protos implied, probably a stack of the 10" version (6). That will allow up to 102 dB per dipole panel at 35 Hz, or 108 dB considering stereo, and more at higher frequencies. Realistically, eventually I'll use a monopole sub below 40 Hz or so.

~Jon

[PMazz]

My LAs are xed over at 500Hz with a Marchand active xover using 24dB L/R filters. Overall I'm extremely pleased with the sound. The RD50s are excellent sounding but don't look for high SPLs as distortion sets in.





This is a 2 meter on-axis measurement. I created a wider deeper notch filter at 5KHz as the recommended one didn't quite do it for me.




Here is a comparison of the raw response at 5KHz vs the recommended notch filter installed. Disregard the low end as it was an attempt gone bad.




Pete

[Scott Simonian]

I had no idea that the cavity resonance was that bad. Not to mention how poorly that notch worked. How was your's different, Pete? BTW- the frequency responce below 200hz includes those woofers too?

[Dennis H]

Note the scale on Pete's graphs, 3dB per division. That makes things look worse than the typical 5 or 10dB graph.

[Paul W]

Hey Jon,
I realize you are busy, but there are some of us who would like to see and hear about the "big iron" just as soon as possible :T
Paul

[thylantyr]

:clap: ;b>

[PMazz]

I had no idea that the cavity resonance was that bad. Not to mention how poorly that notch worked. How was your's different, Pete? BTW- the frequency responce below 200hz includes those woofers too?

I tried a few different iterations on the notch. The inductor was a little bigger, the cap smaller and the resistor bigger. The downside is it pulls the higher freqs down a tad as well. To be honest, I don't remember the exact values but I could look if anyone needs them.

The low end response was back when I was trying to integrate the RD50s to a "bass box" using a single Peerless CSX 10"er below the ribbons. I tried a few combinations with them but as soon as I heard the integration of the current configuration, a line of midwoofs, I was hooked. I have 12 RS180s that will be replacing the Dayton Aluminums.

Pete

[JonMarsh]

I think you'll really like those RS180's in your system, Pete. They're sweet drivers, especially for the cost. One of the top class 7's available, and priced more like the cheap guys. I hope you report back when you've got that "conversion" done.

~Jon

[PMazz]

I think you'll really like those RS180's in your system, Pete. They're sweet drivers, especially for the cost. One of the top class 7's available, and priced more like the cheap guys. I hope you report back when you've got that "conversion" done.

~Jon

I hope so Jon. I've got things started back up again on the media center and I'm close to building the enclosures, as well as the center channel you designed. I'm still testing screen materials for the FP and this has taken the most time, along with all the other "to do" lists, and of course some procrastination.

Pete

[JonMarsh]

Hey Jon,
I realize you are busy, but there are some of us who would like to see and hear about the "big iron" just as soon as possible :T
Paul

Heck, I'd like to be WORKING on the big iron as soon as possible!
:T :B :lol:

I have a plan- but I'm still a few steps away from that point-

1) Buy Praxis - September or early October

2) Probably buy a DCX2496 for breadboarding/auditioning transfer functions (my main LspCAD system is a laptop- forget emulation, though it might be possible with the HTPC/music server I'm builting- but it only has a MAudio 24/192, good for two way, no more)

3) Evaluate production HiFi Dayton RS 10" sub driver

4) Schedule time off for building first set of panels. I have all the wood, just need time.


And before all that, I should probably have the Arvo's running in something resembling a "completed" configuration. Biggest issue is finding the time...

Everyone have a great Friday- I'm telecommuting from home today, first time I've been able to do that in a couple of months.

~Jon

[Interious]

Jon,
Am I correct in assuming that the Saint Saens will be designed around the RD50, and not RD75?
Dave

[JonMarsh]

Jon,
Am I correct in assuming that the Saint Saens will be designed around the RD50, and not RD75?
Dave

Mine will be, because I have a set of new RD50's, and I didn't care about having a taller upper midrange radiator. OTOH, there's no reason someone else couldn't go with the RD75 if that's what they have. There could be some advantages, in max output level, and possibly in getting a taller source with better floor images, though in that frequency range I don't think it's necessary. I'd prefer to have this setup for a very wide range of optimal listening distance (which a taller source may aid), but it's the LF source that's more problematical in that regard, anyway.

~Jon

[Interious]

Ok Jon. There was a guy on Madisound selling a pair of RD50s for $375. I almost bought them, but alas--they are gone. The price of procrastination.
Dave