So I rebuilt my Betsy K speakers, upgraded the woofers to Eminence Delta 15LFAs..........and went a little crazy with EnAbling and using duct seal on the drivers' frames. These are just prototypes (aren't they all?), so I thought what the hell and EnAbled the baffles too. My impression of the process........it works! Maybe I just wanted it too, but I did one Betsy, and left the other stock. The EnAbled Betsy seemed to fill the room better, and brought out more detail. The sound just kinda hung in the air, and made localizing the driver more difficult, one of my main goals with this new build.
I also grounded the baskets of all the drivers to the ground on the amps with separate wires from the main speaker cables. This seemed to clean up the sound just a tiny bit, but again that may just be because that's what I wanted to hear, I won't rule out the psychological influence. Feeling brave, I cut out the dust caps on Betsy and made some phase plugs out of balsa, seems to spread out the HF much better.
The Betsy baffles are mounted with muffler clamps to some bookshelf speakers I made a while back for some Klipsch speakers I had. These are filled with sand and spiked to the floor. The idea here is to isolate the fullranges from the vibrations created by the woofers, and it works perfectly. This was a huge improvement over the single baffle approach. Also much better than having the Betsy baffles sitting on the woofer U-frames like I had before. I've got some old dome tweeters mounted on the back out of phase, with a cap crossing them at about 2500hz. I measured Betsy's rear output, and they have a nice gentle roll-off around I think 2k-2.5k (the idea being to have equal front and rear output).
The open U-frames for the Deltas are made with about 15 degrees of lean back, to get them aiming up at my head. These are also spiked to the floor. I made up some magnet mounts out of MDF as well, tying the sides of the u-frame together. This makes them much stiffer, and cleans up the bass.
The interior of the all the baskets have been duct sealed, as well as felted to reduce reflections. I was looking through old DiyA posts about driver mods, and saw guys streamlining the back of the baskets on their fullrangers, and gave it a go. Probably a little extreme, and I'm not sure I heard any improvement, but in theory it makes sense so it'll stay.
I've been playing with different xo and eq settings on my MiniDSP. Right now I've got the Betsy's eq'd relatively flat, and I'm using the dipole roll-off as the HP (right around 300hz). I've got a 48db Butterworth HP at 150 hz to cut the low frequencies. I've eq'd the woofers with a 3 db house curve from 80-200hz. They roll off with a 24 db slope at about 35 hz, with a 12db butterworth LP at 250hz. I've got 2 subs covering the bottom octave.
So how does this mess sound? Pretty f-ing good! Nice detailed, but laid back sound. For the most part the speakers disappear. The bass from the Deltas is quite good, although a heavy hand with the eq was needed to get these mid-Q drivers to work in an open baffle. They play pretty clean up into the mid-range as well.
Essay over! Nate
I also grounded the baskets of all the drivers to the ground on the amps with separate wires from the main speaker cables. This seemed to clean up the sound just a tiny bit, but again that may just be because that's what I wanted to hear, I won't rule out the psychological influence. Feeling brave, I cut out the dust caps on Betsy and made some phase plugs out of balsa, seems to spread out the HF much better.
The Betsy baffles are mounted with muffler clamps to some bookshelf speakers I made a while back for some Klipsch speakers I had. These are filled with sand and spiked to the floor. The idea here is to isolate the fullranges from the vibrations created by the woofers, and it works perfectly. This was a huge improvement over the single baffle approach. Also much better than having the Betsy baffles sitting on the woofer U-frames like I had before. I've got some old dome tweeters mounted on the back out of phase, with a cap crossing them at about 2500hz. I measured Betsy's rear output, and they have a nice gentle roll-off around I think 2k-2.5k (the idea being to have equal front and rear output).
The open U-frames for the Deltas are made with about 15 degrees of lean back, to get them aiming up at my head. These are also spiked to the floor. I made up some magnet mounts out of MDF as well, tying the sides of the u-frame together. This makes them much stiffer, and cleans up the bass.
The interior of the all the baskets have been duct sealed, as well as felted to reduce reflections. I was looking through old DiyA posts about driver mods, and saw guys streamlining the back of the baskets on their fullrangers, and gave it a go. Probably a little extreme, and I'm not sure I heard any improvement, but in theory it makes sense so it'll stay.
I've been playing with different xo and eq settings on my MiniDSP. Right now I've got the Betsy's eq'd relatively flat, and I'm using the dipole roll-off as the HP (right around 300hz). I've got a 48db Butterworth HP at 150 hz to cut the low frequencies. I've eq'd the woofers with a 3 db house curve from 80-200hz. They roll off with a 24 db slope at about 35 hz, with a 12db butterworth LP at 250hz. I've got 2 subs covering the bottom octave.
So how does this mess sound? Pretty f-ing good! Nice detailed, but laid back sound. For the most part the speakers disappear. The bass from the Deltas is quite good, although a heavy hand with the eq was needed to get these mid-Q drivers to work in an open baffle. They play pretty clean up into the mid-range as well.
Essay over! Nate
Attachments
Nate,
Those look fantastic! I wonder about using some series resitance to raise the effective Q of the Deltas. Either some high watt resistors or really small wire. It might reduce your need for EQ. I think its really interesting that stiffening the frames improved the bass. I might give that a try!
Paul
Wild Burro Audio Labs - DIY Full Range Speakers
Those look fantastic! I wonder about using some series resitance to raise the effective Q of the Deltas. Either some high watt resistors or really small wire. It might reduce your need for EQ. I think its really interesting that stiffening the frames improved the bass. I might give that a try!
Paul
Wild Burro Audio Labs - DIY Full Range Speakers
Thanks guys, I'm having fun! These have been built for about a month and a half now, with no changes to the basic baffle layout. That's the longest I've stayed with one design since I started this OB insanity back in April or so. I just might have to make a nice version out of ply. I started work as a machinist a couple months ago so hopefully in time I can start doing some really cool stuff in metal.
As far as stiffening the frames, I think coupling the magnet to the u-frames is the way to go. Seemed to "tighten" up the bass quite a bit. I've thought about adding resistance to the Deltas, altho I'm happy with their performance as is........I chose the lower Q value on purpose. They say a lower q woofer is tighter in the bass, and comparing it to those Jensen's I'd have to agree...........night and day difference. Build quality plays a part too I'm sure, these Eminence woofers are damn nice!
As far as stiffening the frames, I think coupling the magnet to the u-frames is the way to go. Seemed to "tighten" up the bass quite a bit. I've thought about adding resistance to the Deltas, altho I'm happy with their performance as is........I chose the lower Q value on purpose. They say a lower q woofer is tighter in the bass, and comparing it to those Jensen's I'd have to agree...........night and day difference. Build quality plays a part too I'm sure, these Eminence woofers are damn nice!
- Status
- This old topic is closed. If you want to reopen this topic, contact a moderator using the "Report Post" button.