Hi, soon I'll receive a pair of new Lowther PM2A driver. SInce I have to burn in them, I'm thinking to combine two works:
1. burning in drivers and
2. try them on open baffle configuration.
Normally I build BLH cabinets, but having never tried OB I would like this configuration too.
Do you have an idea of dimensions of panels (front and wings) for this project? I've no woofer at home, and being this an experiment I don't want to buy them. From this the question about one way OB.
Many thanks
Ziocalepino
1. burning in drivers and
2. try them on open baffle configuration.
Normally I build BLH cabinets, but having never tried OB I would like this configuration too.
Do you have an idea of dimensions of panels (front and wings) for this project? I've no woofer at home, and being this an experiment I don't want to buy them. From this the question about one way OB.
Many thanks
Ziocalepino
120\50 or bigger. With wings, asymmetrical.
I have baffle from old project - Visaton NoBox.
Listen my EX3 for test only, no bass, but voices are free and so live...
I have baffle from old project - Visaton NoBox.
Listen my EX3 for test only, no bass, but voices are free and so live...
The Lowther America site has plans for two different OBs using the PM6A rather than the PM2A (Open Baffles Lowthers) . Both use a helper woofer which I believe is necessary for Lowthers in OBs. Martin King also developed two different OBs for a Lowther PM2C using helper woofers. His projects are very well documented here Project 10 : Lowther Open Baffle / Acoustic Elegance H Frame System. Both projects are massive OBs as a consequence of trying to match the woofers to a very sensitive full range driver.
Yes. If you have a lot of space, try bigger baffle, for more bass 🙂
My advice is to try asymmetrical position of PM2A, you can calculate it with Edge:
Tolvan Data
My advice is to try asymmetrical position of PM2A, you can calculate it with Edge:
Tolvan Data
It's fun to experiment. But even if your baffle is one mile wide, and one mile high, you will have exactly zero bass with that driver. I'm not discouraging you, though -- try it!
Hi, I am about in the same stage,
have received PM2C (still not bad) and am going open baffle. I am now making a new surround, will mount in OB full band first [too] just to get acquainted.
I also plan to go OB, with a sub, like Jon Ver Halen does, with for example the Altec 416.
I was following a RFT L3702 on Ebay, but man, once imported they are more expensive than new GPA Altecs. They do simulate as nice though. The RFT's are from organ cabinets, and like old Wurlitzer parts (Jensen 12N), some have mixed feelings about the use as Hifi speaker. For € 500 I am not willing to experiment.
But on selling fora in East Europe (e.g Hungary) these speakers are sold for less than €30, now that becomes interesting. Four * L3701 would do nice in a H-frame configuration (two 'facing' each other).
The simulation:
Baffle Height (mm) 1000
Baffle Width (mm) 1100
Hight above floor (mm) 300
Dist. rear Wall (mm) 1000
Dist. side Wall (mm) 1300
As you can see the RFT and LOMO and even Altec are too sensitive for a simple match on paper; this looks like it might require bi-amping; but, what Jon did was cross over very low and then . . the mismatch disappears. Interesting concept.
I simulated various heath/width combo's. Unit at 30 cm from floor.
I plan to go for 60 cm wide for the bass section, with 30 cm solid side flanks, making the acoustic path effectively 1m05-1m10. High: 1 meter should be enough - the GREEN line. Higher up the board there is no need for the flanks or wings; like Jon does.
have received PM2C (still not bad) and am going open baffle. I am now making a new surround, will mount in OB full band first [too] just to get acquainted.
I though of a horn, but too cumbersome and many have colorations because of sharp bends; though I like the Zen-Acousta, which is an unfolded Acousta as far as I can see. The PM2 according to calculations needs a smaller throat than the Acousta provides. So here we are too much juggling, and as a Sceptic, 😱 this time I dropped the idea.
I also plan to go OB, with a sub, like Jon Ver Halen does, with for example the Altec 416.
I was following a RFT L3702 on Ebay, but man, once imported they are more expensive than new GPA Altecs. They do simulate as nice though. The RFT's are from organ cabinets, and like old Wurlitzer parts (Jensen 12N), some have mixed feelings about the use as Hifi speaker. For € 500 I am not willing to experiment.
But on selling fora in East Europe (e.g Hungary) these speakers are sold for less than €30, now that becomes interesting. Four * L3701 would do nice in a H-frame configuration (two 'facing' each other).
The simulation:
Baffle Height (mm) 1000
Baffle Width (mm) 1100
Hight above floor (mm) 300
Dist. rear Wall (mm) 1000
Dist. side Wall (mm) 1300
As you can see the RFT and LOMO and even Altec are too sensitive for a simple match on paper; this looks like it might require bi-amping; but, what Jon did was cross over very low and then . . the mismatch disappears. Interesting concept.
I simulated various heath/width combo's. Unit at 30 cm from floor.
I plan to go for 60 cm wide for the bass section, with 30 cm solid side flanks, making the acoustic path effectively 1m05-1m10. High: 1 meter should be enough - the GREEN line. Higher up the board there is no need for the flanks or wings; like Jon does.
Have added a sim of just Open Baffle with my PM2:
The headings tell height x width.
A smaller top section flattens the response!
albert
The headings tell height x width.
A smaller top section flattens the response!
albert
And Ziocalepino
How did you fare with test-OB's?
I installed an OB with one speaker (mono-one channel. I have one piece of wood fit for it)
The first 30 seconds were scaring, the fast transients and impulse response drove me mad. It just jumped at me, like a voracious tiger.
Changing source from pop to classic voice, made it more agreeable, then the power amp switching started, and a tube amp gave good results. And with some 10 dB of feedback the sound was tamed too.
Now a few days living with this one channel, the speaker settles down, breaks in, the harsh sound goes away. Even without the bass, songs are understandable. It sounds very nice in the house.
BAD BAD - the high sensitivity shows power line ticks! [My old speaker at 87db did not show much). So home work to do for me. Make a passive preamp (just a buffer after a pot meter).
How did you fare with test-OB's?
I installed an OB with one speaker (mono-one channel. I have one piece of wood fit for it)
The first 30 seconds were scaring, the fast transients and impulse response drove me mad. It just jumped at me, like a voracious tiger.
Changing source from pop to classic voice, made it more agreeable, then the power amp switching started, and a tube amp gave good results. And with some 10 dB of feedback the sound was tamed too.
Now a few days living with this one channel, the speaker settles down, breaks in, the harsh sound goes away. Even without the bass, songs are understandable. It sounds very nice in the house.
BAD BAD - the high sensitivity shows power line ticks! [My old speaker at 87db did not show much). So home work to do for me. Make a passive preamp (just a buffer after a pot meter).
- I am at a crossroads still if I do a horn or continue with an OB.
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