Open Baffle Epiphany!
- Thread starter cptnCanada
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Poultrygeist
Lunatic Member
OK thanks for the comments on the felt dust caps. Again, I think I'll just leave 'em alone. Here's a pic of the drivers I have coming:
They are 8" Heppner pulls from an organ.
Very interesting. If they came from a tube organ they should be fairly efficient.
hnash53
Super Member
Regarding the employment of large woofers for bass performance, and the use of H-frames, how do you power them since they are separate from your full range driver?
Do you use an amp/receiver that has separate A and B speakers?
I currently have a 12" Polk subwoofer for the low end... but am considering building an H-frame with a 12" driver in it and trying it in place of the sub. I just need to find out how you guys are driving these separate drivers.
Thanks.
Do you use an amp/receiver that has separate A and B speakers?
I currently have a 12" Polk subwoofer for the low end... but am considering building an H-frame with a 12" driver in it and trying it in place of the sub. I just need to find out how you guys are driving these separate drivers.
Thanks.
Poultrygeist
Lunatic Member
I drive two H-frame Alphas in parallel with a single Yung SD 100 class D plate amp. I paid $79 at Parts Express for mine but I see they're now priced at $99. I use Y cables off the preamp and feed the Yung and the main amp line level simultaneously. The full range speakers run full range while the Alphas use the Yung crossover to filter the HF.
Poultrygeist
Lunatic Member
On the lower left is a Yung plate amp in a frame I built. I've seen some folks place plate amps in wooden tissue boxes and even picture frames. It just needs to be elevated with two binding posts installed on the rear of the open frame.
Son-of-Vere
Super Member
On to phase 3, or "Where in the hell do I put the tweeters?" The old console tweeters are currently in the winners circle, as they are light, and have a vent in the back to give them at least some dipole ability. It seems like they like to reside 3" directly above the woofer. I tried doing some research on speaker placement on the baffle, but couldn't really find anything useful. I'm open to suggestions in case there's some rule I'm breaking.
I'm just about ready to commit to wood, and I've got a line on a faux leather covering idea for the front. After listening to these things in cardboard, and living with the fart noises, I'm starting to wonder if having a "lively" baffle isn't such a bad idea. These things must be light, or they'll get ignored, as they're too big to hang around in the listening area. I realize that smaller baffles are possible, but those are usually supplemented by H frames, and I don't want to go there just yet.
I'm just about ready to commit to wood, and I've got a line on a faux leather covering idea for the front. After listening to these things in cardboard, and living with the fart noises, I'm starting to wonder if having a "lively" baffle isn't such a bad idea. These things must be light, or they'll get ignored, as they're too big to hang around in the listening area. I realize that smaller baffles are possible, but those are usually supplemented by H frames, and I don't want to go there just yet.
hnash53
Super Member
What are you using, PG, for your "main amp"? The Nobsound is an integrated tube amp isn't it... tube preamp and a solid state amp? I had one of those Nobsounds awhile back.
Is it possible to drive the H-frame woofer with a receiver that has the A & B speaker outputs? Filter the highs going out the B speaker outputs to the H-frame woofer with a capacitor?
I've not worked much with separates or plate amps yet/before.
Is it possible to drive the H-frame woofer with a receiver that has the A & B speaker outputs? Filter the highs going out the B speaker outputs to the H-frame woofer with a capacitor?
I've not worked much with separates or plate amps yet/before.
Have you considered folding panels such as this? http://glowinthedarkaudio.com/openbaffle.html
You could make the center out of heavier wood (I was actually considering oak stair thread) and use something lighter for the wings.
Plus you can fold them up and move them out of the way when necessary.
Son-of-Vere
Super Member
Yes, I have. But I like what these do, I'd hate to have to start over. I may try them out before I put a finish on them. I may build just one. That way if it's a trainwreck, I'm just out some wood. I am going to incorporate some handles like he did, however.
Poultrygeist
Lunatic Member
I'm currently driving the Zeniths with a Volt+ TPA3118 amp ( the one with a lighting bolt ) and it matches so well with the Nobsound preamp.
Poultrygeist
Lunatic Member
I've also tried the Zenith/H-frames with the Bottlehead 2a3 SET mono blocks and would have to say that's probably the best combination. I'll be rotating these between the Zeniths and flat baffle Lowthers.
Poultrygeist
Lunatic Member
"where to put the tweeter?"
This worked for me and it's at ear level.
This worked for me and it's at ear level.
Poultrygeist
Lunatic Member
Some of you might be interested in these OB's from Urban Fidelity which combine art and audio. Notice it's just a single driver in a relatively narrow baffle. I think Commonsense Audio used to sell those full range drivers.
http://www.stereophile.com/content/urban-fidelity-art-speakers#iVifHBgeOLCWlfS7.97
http://www.stereophile.com/content/urban-fidelity-art-speakers#iVifHBgeOLCWlfS7.97
Poultrygeist
Lunatic Member
hnash,
I'd recommend amping the full range drivers and woofers separately. Here I used a PE low pass filter ( 80hz ? ) on the woofers and drove them with an old AV receiver in 2 channel mode. The full range Betsy drivers I ran full range powered by a APPJ Miniwatt SET amp.
I'd recommend amping the full range drivers and woofers separately. Here I used a PE low pass filter ( 80hz ? ) on the woofers and drove them with an old AV receiver in 2 channel mode. The full range Betsy drivers I ran full range powered by a APPJ Miniwatt SET amp.
hnash53
Super Member
"where to put the tweeter?"
This worked for me and it's at ear level.
The H-frame here... that's a 15 inch woofer, right? I've got one coming now and wanted to know what the dimensions were of your H-frame here.
Thanks.
Poultrygeist
Lunatic Member
Yes it's the Eminence Alpha 15. All interior dimensions of this open ended cube are 17 inches.
The middle baffle which mounts the Alpha is located in the center of the cube.
The middle baffle which mounts the Alpha is located in the center of the cube.
The builds in this thread peaked my interest so I threw this together. Small room and open baffles do not seem to mix well. Two to three foot from wall is not happening in a 10 by 10 foot room. A pair of gutted Magnavox Belvederes using the woofers fullrange sounds better than they look.The lids are at 62 degrees from horizontal.
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hnash53
Super Member
Oh man, I like the set up!!! Bet the sound from those cabs is rich.
hnash53
Super Member
Just what I needed... thanks so much. Gonna give the H-frame a try with a 15 inch woofer.