Poultrygeist
Lunatic Member
These are hybrid OB's over H-frames and they run full range as well.
Open Baffle Epiphany!
- Thread starter cptnCanada
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Poultrygeist
Lunatic Member
I'm but an OB novice but I have done lots of experimentation with some good results and some not so good. Having played in bands and orchestras for most of my life I do know how music should sound and my FR speakers sound better used as a full range speaker with no restrictions and no filters. Mine is a very simple approach and that is to bring in the woofers to fill in what the full rangers can't do. OTOH a passive crossover tries to do the impossible and that is to perfectly stitch two different speakers together.
Poultrygeist
Lunatic Member
To avoid a passive crossover I tried an active on the HF and LF. While it might be technically accurate it was a compromise I couldn't tolerate. With the active in the signal path my SET amps driving the full range speakers totally lost their magic and sounded like cheap solid state amps. I still use the Ashly active but only on the woofers. For resolving detail at low levels ( primarily acoustic jazz ) my system certainly works for me.
Impossible? Maybe what you should say is that you have not been able to implement a crossover that you like with your equipment. A passive crossover can transition a signal between two drivers seamlessly if done correctly.
Poultrygeist
Lunatic Member
Just paraphased from the Lenard Audio Institute:
3 laws of Crossovers
- It is not possible to stitch 2 different speakers together, perfectly.
- A crossover should have the minimalist complexity to achieve the desired outcome.
- The more complex a crossover, the more difficult the system is to control.
essNeff
Active Member
I see that you addressed the BP gain by "separating" the xo points by 300 hz. to eliminate the "hump".
I can certainly see your point in doing this. Your reason's for doing so makes sense.
I am using an Fmod 70hz. 12 db LP for the Alpha's. I am also using the TB 1808 FR.
I could see where the TB would benefit by offloading the lower octave or two.
I will experiment with a 12db HP on the 1808, perhaps around 280 hz or so as a starting point.
Thanks, Dr. King!
Attachments
So having two different drivers mounted in two different locations in space and possibly two different configurations (OB and H frame) with the goal of getting a smooth SPL response (magnitude and phase) at a listening position, I can only see a well designed crossover as a method for achieving this goal. It is not perfect as no speaker can reproduce live music perfectly.
To me the least likely method to achieve a smooth response is no crossover at all between the two drivers which is consistent with the direction the "Laws" are leaning. You can't get more minimal than none. The next method seeming to be a slight improvement is a crossover on only one driver with the other running full range. The best chance of achieving a smooth summed magnitude and phase response from two drivers in two locations in space is to have a well designed crossover on both drivers. It seems like a very logical progression to me. I will agree that a simpler crossovers on both drivers has worked better in my designs.
The only time I have not seen a crossover work for my OB speakers is when using a tube amp. Using my 15 watt tube amp with low frequency crossover dipole systems I have designed and built resulted in bass output being severely attenuated. I believe this was caused by the tube amp's performance being strongly dependent on the electrical load imposed by the speaker system, a SS amp worked great. It was not the fault of the crossover, it was poor performance from the tube amp. This happens a lot, Low powered tube amps are not as stable/linear when driving difficult speaker loads. In my opinion tube amps are giant tone controls with the sound dependent on the tubes being used and the load being driven.
ScooterMcTav
I know less than I think
Well, my OB experiment has ended before it began.
A set of Vandy Model II just came up on local classifieds, so I'm trading the owner my Celestion Ditton 15 and some cash for them.
Actually quite excited to hear them.
A set of Vandy Model II just came up on local classifieds, so I'm trading the owner my Celestion Ditton 15 and some cash for them.
Actually quite excited to hear them.
Poultrygeist
Lunatic Member
We both scored!
A nice pair of Zenith 49CZ852's came up for sale on that auction site, so I snapped them up. I'm happy with my find, but I could see my way to trade you straight across for the Vandy's.
Once you hear the Zeniths I doubt you'll want to trade them.
mkane
Lunatic Member
While satisfied to a point with the bass in my novice set up unplugging the FR speakers and listening to just the woofers with the Dayton the sound is terrible. I'm positive I have the Dayton wire incorrectly ( both woofers are connected to the sub out plugs )So, I made a big change. Removed the active crossover and the plate amp. Now running the SET pushing the FR speakers using a transformer volume control, wired up the Mac 275 with an active pre amp to the woofers. Much cleaner sounding bass. I need to figure out how to incorporate the active crosser on the woofers next. We went to a concert last night and I got an earful of live music so today is comparison day. Glad it's raining.
Roscoe Primrose
New Member
As long as you don't play any Opera you should be safeThat's a bad thing at my house, skylights in the listening (living) room
Roscoe
Roscoe Primrose
New Member
jelly_bean
Active Member
We both scored!
A nice pair of Zenith 49CZ852's came up for sale on that auction site, so I snapped them up. I'm happy with my find, but I could see my way to trade you straight across for the Vandy's.
I ALMOST snatched those up. Was a bit more than I wanted to pay at the moment.- But he knew what he had.
Someday. Also, I am looking around for a new (or old) driver to try out. I really like the smoothness of the old AlNiCo speakers in OB but really want it to be dynamic.
jelly_bean
Active Member
Do let us know how they turn out! I may hunt down a pair of them. If they're as good as everyone says, I might have to before things get too out of hand.
Poultrygeist
Lunatic Member
Yeah, he obviously did his home work before listing them. Apparently word has gotten out - Way to go Poultrygeist!
I was afraid the price would skyrocket but if I hadn't gushed over my pair y'all might not have given them a second look. So how much did they set you back?
Mr "Glow-in-the Dark" says the Zeniths have dominated his OB speaker world for the past 18 months resulting in his selling off the Rullit field coils and a pair of Supravox. That puts the Zeniths in some very select company. Always wanted to try the expensive French built Supravox but if the Zeniths nudged them out the door that's saying a lot. I couldn't be happier with the way they sound in my system. My son-in-law is a rep for Martin Logan and he's totally blown away by them. When he's in town it's not uncommon for him to bring his business friends over for a listen. I'm not bragging but I've seen a lot of head scratching in disbelief. I've owned some nice speakers from Meridian and Aerial Acoustics but they couldn't hold a candle to these home brew OB's.
Poultrygeist
Lunatic Member
The cheapest way to get a pair may be through buying an old Zenith console. I paid $35 for one, sold it's mono tube amp for $75 and it's turn table for $25.
Felt kinda guilty for dismantling and gutting the console but I still plan on using some of it's wood
Felt kinda guilty for dismantling and gutting the console but I still plan on using some of it's wood