135 hz Mid Bass Horn
To compliment the Spiral Bass Horn, I've designed a new mid bass horn. It's 3 db. down point is 135 hz. The B&C 8PE21 eight inch driver powers this creation, and what a delightful creation it is...
Because the spiral bass horn is extremely smooth, I'm able to cross the sub bass at a higher frequency. This results in the need for an articulate mid bass horn to compliment that crossover point.
The original 100 hz mid bass horn (detailed elsewhere on this site) is great with sub woofers that require a 100 hz crossover, but when used with the spiral bass horn there's too much energy in the upper bass and not enough emphasis on the mid range. Of course the added energy comes from the spiral bass horn being crossed at 135 instead of 100 hz. To that end I offer the 135 hz mid bass horn.
The original 100 hz mid bass horn (detailed elsewhere on this site) is great with sub woofers that require a 100 hz crossover, but when used with the spiral bass horn there's too much energy in the upper bass and not enough emphasis on the mid range. Of course the added energy comes from the spiral bass horn being crossed at 135 instead of 100 hz. To that end I offer the 135 hz mid bass horn.
Below: Here's the predicted SPL response. That's a beautiful, flat response curve. There's about three octaves of bandwidth with this horn/driver combo.
The impulse response is a tad weaker than horns with an adapter chamber. Still, the B&C 8PE21 eight inch driver is quick and the overall sound has striking realism--better than the 100 hz mid bass horn with the B&C 12PE32 driver.
Listening impressions:
Initially, the design rather startled me. Being that the horn is long and has a small throat, I expected anomalies. I felt extremely satisfied when I heard beautiful music and no distortion. Because this horn uses an efficient eight inch driver with a powerful motor, there's plenty of bandwidth. The EBP (efficiency bandwidth product) of this driver is 435! This explains why the driver has excellent high end extension in a horn. I've discovered a gem with this particular device.
I like to listen to music that's thirty to forty years old. Maybe it's because the original recordings were analogue, I'm not certain, but the end result is that there's a realism created with this horn that's especially inviting with older recordings. Aside from being smooth (an absolute must in horn design) the transients are startling. The blending of mid bass and treble at 500 hz is absolutely seamless. My paper mache horns now have the perfect match.
Drum snaps are crisp, but slap bass guitar is especially striking. There's an accentuation, a thrust if you will. I couldn't wipe the grin of my face if I tried. Effects like lightening (hard to get a real slap of thunder in older recordings) are much more believable. Without a doubt, there's romance with older music.
I like to listen to music that's thirty to forty years old. Maybe it's because the original recordings were analogue, I'm not certain, but the end result is that there's a realism created with this horn that's especially inviting with older recordings. Aside from being smooth (an absolute must in horn design) the transients are startling. The blending of mid bass and treble at 500 hz is absolutely seamless. My paper mache horns now have the perfect match.
Drum snaps are crisp, but slap bass guitar is especially striking. There's an accentuation, a thrust if you will. I couldn't wipe the grin of my face if I tried. Effects like lightening (hard to get a real slap of thunder in older recordings) are much more believable. Without a doubt, there's romance with older music.
Do you want more?!?
If you can tolerate an additional seven inches of length and a mouth who's inner dimensions are 21.25" x 21.25", you can have an SPL curve that matches the graph, below. Oh, and you get to use four B&C 8PE21 drivers per horn. In this sim, I wired the four drivers in parallel, which explains the potent SPL. Naturally, you can wire the drivers in a series/parallel configuration and make your power amplifier much happier. I think I'm going to have to build a pair! :^)
And if you want to have a lower cutoff:
I've tinkered around with the length and flair expansion rate, and this is what I've come up with. It's almost as smooth as the 105 hz horn immediately above, but it get's down to around 80 hz. A cutoff this low is a bit of the holy grail as far as mid bass goes.
It began with my DIY electronic crossover, oddly enough. I configured it to drop the spiral bass horns at 80 hz, or thereabouts, and I like the way it sounds. I can increase the gain quite a bit on the bottom end, and tame the bass bloom with strong mid bass. This way, I get all that super deep bass slam from the kick drums, timpani, organ, five string bass, etc., and have it sound crisp. Sloppy sounding bass is inexcusable...
It began with my DIY electronic crossover, oddly enough. I configured it to drop the spiral bass horns at 80 hz, or thereabouts, and I like the way it sounds. I can increase the gain quite a bit on the bottom end, and tame the bass bloom with strong mid bass. This way, I get all that super deep bass slam from the kick drums, timpani, organ, five string bass, etc., and have it sound crisp. Sloppy sounding bass is inexcusable...
The way I see it, in order to fit four drivers to this beast, I'll quarter the rear two expansion segments. This gives me four smaller horns that meet at the junction of the third expansion segment.
There's a 12 sided petal version on the drawing board:
Click on the drawing to enlarge.
Prints are available for $25.00.