The Round Mound of Sound

[Randy in Caintuck]

Hi fastbike,

I appreciate the thought .....

However, after some extensive listening over several days, I came to the conclusion that I was not totally happy with the results.

When I built these baffles, I was hoping against hope that I could "get away" with a 12" width on the part of the baffles where the 8" Betsy drivers are mounted. The focus, detail and ability to "disappear" were everything I could have hoped for. However, on almost everything except what I consider to be the very best recorded CDs in my collection (Stockfisch and some others) the midrange and lower mids were just too "thin" sounding and lightweight.

From my experience with the Betsy drivers in other baffles, I knew in my heart that this would be the case ..... but reality finally backed me into a corner .....

So, I made a modification to the baffles to widen the area where the Betsy drivers are mounted and it made a major improvement in the tonal balance.

I have renamed the speakers the "Darth Baffles" .....

Larger photos here and here.

All of the good qualities of the original speakers have remained, and the "stealth" aspect of the black baffle extensions makes them disappear very nicely, especially in a room with subdued lighting.

For a fact, building loudspeakers is a learning experience ..... especially for those of us flying by the seat of our pants ..... and I am enjoying the journey

Happy listening,

Randy

 

[pjanda1]

One of the fun things about OBs is how easy they are to modify. (Imagine, for a second, serious after-the-fact modifications to a BLH!) So, they are especially well suited to figure-it-out-as-you-go (which might be less generously termed WAG) methods.

Complicated as my current system is, I bet I built the baffles in about an hour, and used wood from the original folding baffles, no less!

They look great Randy!

Paul
Wild Burro Audio Labs - DIY Full Range Speakers

 

[Randy in Caintuck]

One of the fun things about OBs is how easy they are to modify. (Imagine, for a second, serious after-the-fact modifications to a BLH!) So, they are especially well suited to figure-it-out-as-you-go (which might be less generously termed WAG) methods.

Complicated as my current system is, I bet I built the baffles in about an hour, and used wood from the original folding baffles, no less!

They look great Randy!

Paul
Wild Burro Audio Labs - DIY Full Range Speakers

Thanks Paul .....

I am doing my best to spread the word about the Betsy drivers. They really are amazing and everyone who has heard them in my system has been bowled over by the great sound. When the Betsy drivers are mated with decent amplification and a good front end, they put on a very realistic presentation.
One of my good friends visited me a few nights ago and we spent about 4 hours in a listening session.
When he pried himself out of the listening seat, he said "thank you so much for inviting me to the private concert" .....

That's what it's all about .....

Best wishes,

Randy

 

[keantoken]

I've been using them for prototyping my amplifier designs. Not tube, but hear me out. I designed an amplifier with an output stage with it's own feedback loop. The spatial illusion was so effective I could listen in mono with one ear towards the speakers and it would seem I was hearing some instruments with the wrong ear. Doing it took a lot of hit-and-miss though. I think these speakers are capable of incredible image depth and realism - like the instruments are right in the room and if you close your eyes you can't tell the sound comes from a speaker, and you can hear the hall reverberations and everything. I have the old fuzzy cone versions. I would love to try out the newer ones (maybe they're more resistant to cat claws?). Eventually I want to try an active EQ, whenever I have a setup capable of accurately measuring the response.

 

[zimmer64]

Hi there,

I want to give my Betsy's another try. The winged baffles did not produce enough bass for my taste, so Betsy had to go back into the basement.....

I now went off and ordered a pair of Eminence Alpha 15 A, a miniDSP and a measurement microphone. Not all the parts have yet arrived. I plan to use a 20" x 38" baffle. 2 SS amps are also already available.

My question to the community is: Do you leave Betsy full range and the woofers playing as a sub? Or are you adding a high pass filter? Where do you cross?

Thank you in advance for any input and help!

Best

Michael

 

[cpmiller]

Hi Michael,
That's an interesting question which I think about as well.

I am not bi-amping as I'm experimenting with different tube amps but I started using the Alpha 15A through a low pass with a BetsyK w/o any filter (but phase corrected the connections). I now use a Deltalite 2515 as the sub with a different LP (2nd order LP of Troles Gravesen's OB11 w/o the attenuation) but still the same basic setup. I choose to do it that way to get the maximum speaker sensitivity.

While I supposed the phase alignment is not as well matched as when using a HP for the Besty and LP for the subwoofer, the drivers combine very well. I have read of numerous other speaker designs with this kind of set up as well, so I don't think it's a forbidden approach. The situation may also be aided that the cross-over frequency is quite low, at 163Hz. I look forward to hear what others have to say.

Chris

 

[norman bates]

yea, even for midbass, i bet you'd need 2' from front frame edge to back frame edge for meaningful response down to 100hz. My 15" deep OB with an 8" driver rolled around 200hz, driver's mass corner was around 100hz, not the driver's fault there was no bass.

my 24" wide x 19" deep open backed box with 4x4" had some bass.

Maybe put a sonotube behind the betsy, loosely filled with stuffing, but you'll lose front wall mid bounce.

Based on an 8"drivers limited dispersion, I'm suprised a vertical line array wouldn't work. But horizontal dispersion would be small.

Norman