Well ..... as promised, here is some info on another project that will be added to the "Betsy barn" .....
I haven't been secretive about the things I have discovered during my experimentation with open baffle speakers ..... pretty much anything I have found to be useful has been shared with forum readers.
Quite a few DIY folks have benefited from this information and that's a good thing from my perspective ..... since I'm just a DIY guy myself who happens to also sell speakers to music lovers who don't have any tools or the desire to build their own reasonably priced and excellent sounding OB speakers.
Among the things that I have discovered is that the frequency response of open baffle speakers is closely tied to the size of the baffle ..... especially the frequencies from the lower midrange to the bass.
I have heard a pair of 8" Betsy drivers in 4' x 4' baffles that would produce enough bass with a low powered amplifier to loosen a person's dental fillings ..... however, the overall frequency response was a wee bit "bass heavy" for my tastes .....
So, the frequency response can be "seasoned to taste" by the size and shape of the baffle. However, there is another way to increase the lower midrange and upper bass in smaller baffles such as the ones I prefer and offer to my customers ..... and that is to position the drivers closer to room boundaries ..... including the floor.
So, my Betsy baffles do a pretty good job of reproducing upper bass and about half of my customers are using an additional "bass baffle" with a larger driver or some other subwoofer to supplement the low bass.
Several customers have expressed the wish to have "just a little more" upper bass response to accommodate their personal tastes ..... or to allow a more seamless and integrated blend with their low bass system.
In the
"Betsy Deuce" thread, I responded to this request based on a customer's suggestion and added a Betsy driver without a whizzer cone rolled off at 80 HZ with an air core inductor. This seems like a good solution and I am happy with the results. The speaker has a bit more "meat on the bones" than the standard Betsy baffle and it's very easy to integrate it with a low bass system.
Even so, there will be some folks who either want a bit more low bass from a single pair of baffles or simply have no room or desire to place a third (or fourth) baffle or other subwoofer in their listening room.
Enter the "Betsy & Buck" .....
While retaining the same size and shape as the standard Betsy baffle, a 10" Eminence Alpha pro driver has been added with two sets of binding posts ..... one for each driver.
The Alpha driver can either be powered in parallel with the Betsy driver by using an outboard box with an inductor or low pass filter ..... or for even more bass and greater control a plate amp or other power amp with a crossover can be used. One inexpensive plate amp can be used to power the Alpha drivers in both baffles (summed mono) or a pair of plate amps can be used for "stereo bass".
I have tested each of these methods in my listening room and they all work well. Personal taste and preference will determine which method works best .... as well as the main amplifier used for the Betsy drivers.
In the past, I have not used any "gaskets" between the Betsy drivers and the face of the baffles because it just doesn't make that much of a difference at any sane volume level in my opinion. However, I am using a gasket between the 10" driver and baffle surface on these speakers to reduce possible "smearing" of the sound from the Betsy driver.
These are still not "head banger" speakers, but will satisfy the needs of many music lovers who appreciate good sound and want a bit more low bass.
Yes ..... there are photos .....
Larger photos
here,
here and
here.
These speakers will not go quite as low as a separate bass baffle (or two) with 12" or 15" drivers, but will play low enough to satisfy the "bass tooth" of most music lovers.
As with the "Betsy Deuce", I will have a pair of Betsy & Buck speakers at the Decware Zen Fest in October to get some feedback from the attendees.
Happy listening,
Randy