IIRC, Fs was in the mid 50s when I started. It certainly wasn't 45Hz.
Zilla - That H-frame looks good. I wonder if two 12s would do? Stack a 12LTA in a 2 cu. ft. box on top and that would let me have a footprint approx like that of the Hammer Dynamics Super 12. I've experimented a bit with H-frames and really like the sound.
BTW, I have a pair of tweeters to mount co-axially, but that was when I figured I would bring them in above 10k. Now without a whizzer I'll need something I can crossover a lot lower.
Tonight I re-tested both modified and stock drivers. Before I did I played music through them (in free air) for about 10 minutes and then moved the cones by hand. I tested multiple times.
Results - Modified driver - Fs 70 Hz, Qts .56
Stock driver - Fs 72, Qts. .60
The stock driver was used in my classroom for a year so it should be broken in.
Still, it could be my WT3 or something I'm doing, however, I measured a pair of Fountek FR89-8 drivers a month ago and they measured within 2 Fs of mfg specs.
Results - Modified driver - Fs 70 Hz, Qts .56
Stock driver - Fs 72, Qts. .60
The stock driver was used in my classroom for a year so it should be broken in.
Still, it could be my WT3 or something I'm doing, however, I measured a pair of Fountek FR89-8 drivers a month ago and they measured within 2 Fs of mfg specs.
>>> Zilla - That H-frame looks good. I wonder if two 12s would do? Stack a 12LTA in a 2 cu. ft. box on top and that would let me have a footprint approx like that of the Hammer Dynamics Super 12. I've experimented a bit with H-frames and really like the sound.
Thanks, yes i feel like i ended up with an overall size similar to the Hammer Dynamics speaker but that was not intentional. Originally this project was going to be a three box solution (12lta in two 2.5cf boxes and a powered sub in a third 2.5cf box of the same dims)... but the 2.5cf boxes came out ugly and did not extend the bass as much as i had hoped. Partnering them with the H-frames made me realize how much bass was missing. So i went smaller and placed them on top of the H-frames. Whatever bass solution you use (H-frames, powered sub, big *** sealed box, etc...) you need to find a way to extend bass of the 12lta in 'normal' sized boxes. Hammer Dynamics may have the best overall compromise for this driver... somewhere in the 4 to 6 cubic foot range looks ideal but i felt they were too big for my room. Others may be fortunate to have larger rooms for larger speakers.
If you have 12" drivers suitable for open baffle then go for it. I think it will work just fine. It would allow a more streamlined look to have 12" drivers stacked. Look at this pic:
http://www.linkwitzlab.com/images/photos/May0318-1b.JPG
So it's funny to end up with basically the same footprint as the Hammer Dynamics. I could have simply built 4cf boxes... but then i would have to find a place to store the H-frames... but i enjoy them too much to do that. Besides, putting the 12lta into smaller 'monitor' style boxes gives me some flexibility for bass solutions in the future. They are approx the size of Klipsch Heresy's now and that's a pretty small size for such a big sound.
Think of small 12lta sealed speakers as really large monitors that extend to around 100hz with 97db efficiency. Cut off the dustcap to reduce the reverberant sound (i am still playing with tweaks to further improve but have been listening this way for days and enjoy the overall sound). Add tweeter and bass support that suits your room and you will have a great, highly efficient system to use your low powered tube amp or t-amp with. It will sound like you have 1000 watts!
Thanks, yes i feel like i ended up with an overall size similar to the Hammer Dynamics speaker but that was not intentional. Originally this project was going to be a three box solution (12lta in two 2.5cf boxes and a powered sub in a third 2.5cf box of the same dims)... but the 2.5cf boxes came out ugly and did not extend the bass as much as i had hoped. Partnering them with the H-frames made me realize how much bass was missing. So i went smaller and placed them on top of the H-frames. Whatever bass solution you use (H-frames, powered sub, big *** sealed box, etc...) you need to find a way to extend bass of the 12lta in 'normal' sized boxes. Hammer Dynamics may have the best overall compromise for this driver... somewhere in the 4 to 6 cubic foot range looks ideal but i felt they were too big for my room. Others may be fortunate to have larger rooms for larger speakers.
If you have 12" drivers suitable for open baffle then go for it. I think it will work just fine. It would allow a more streamlined look to have 12" drivers stacked. Look at this pic:
http://www.linkwitzlab.com/images/photos/May0318-1b.JPG
So it's funny to end up with basically the same footprint as the Hammer Dynamics. I could have simply built 4cf boxes... but then i would have to find a place to store the H-frames... but i enjoy them too much to do that. Besides, putting the 12lta into smaller 'monitor' style boxes gives me some flexibility for bass solutions in the future. They are approx the size of Klipsch Heresy's now and that's a pretty small size for such a big sound.
Think of small 12lta sealed speakers as really large monitors that extend to around 100hz with 97db efficiency. Cut off the dustcap to reduce the reverberant sound (i am still playing with tweaks to further improve but have been listening this way for days and enjoy the overall sound). Add tweeter and bass support that suits your room and you will have a great, highly efficient system to use your low powered tube amp or t-amp with. It will sound like you have 1000 watts!
12LTA should be nice with appropriate subs - they sound pretty good with 6 string electric guitar and have good presence with the mids of bass guitar. Subjectively in the little Karlson I could get more punch (and spl on bass drum transients with 12" 1114 coaxial made by Eminence with an 80oz ferrite slug and also Eminence's Beta10CX. 12LTA is a fun driver for low cost Here's a 12LTA as direct radiator on and 20 degrees off axis:
An externally hosted image should be here but it was not working when we last tested it.
An externally hosted image should be here but it was not working when we last tested it.
Freddiy, thanks for your comments and measurements. The 12lta frequency response seems to measure consistently. It is inexpensive compared to many of the other full rangers i've used but offers a LOT of fun per dollar. Not the best, but it sure is fun and a good value.
JRKO, i can't wait to read your response when you set the Beta 15s into their cabinets.
Btw, i have been enjoying my new speakers for weeks and the system has really dragged me back into my music collection. CDs are strewn across the floor! Overall, the sound fills the room easily and always impresses. I think it's the effortless detail and up front soundstage. Everything considered, they are warm and full sounding from top to bottom with forward vocals. These speakers have great 'jump' and are very dynamic. I expect to keep them a while since they deliver the musical goods. Honestly, i've stopped driving for perfection and just want to listen to music these days. Life is full of stress for me lately. I'm glad this project found me because it's relatively fuss free to get things sounding good.
I've really come to appreciate pro sound drivers and their capabilities. Maybe for a smaller scale, home audio drivers offer more finesse... but if you crave a big, relaxed, live sound, pro drivers may be the better choice.
The Alpha 15's in H-frames ROCK in my room. They are full, rich and effortless. If their big brothers are better that's great... something to look forward to as a future upgrade. For now, i'm just enjoying music again.
JRKO, i can't wait to read your response when you set the Beta 15s into their cabinets.
Btw, i have been enjoying my new speakers for weeks and the system has really dragged me back into my music collection. CDs are strewn across the floor! Overall, the sound fills the room easily and always impresses. I think it's the effortless detail and up front soundstage. Everything considered, they are warm and full sounding from top to bottom with forward vocals. These speakers have great 'jump' and are very dynamic. I expect to keep them a while since they deliver the musical goods. Honestly, i've stopped driving for perfection and just want to listen to music these days. Life is full of stress for me lately. I'm glad this project found me because it's relatively fuss free to get things sounding good.
I've really come to appreciate pro sound drivers and their capabilities. Maybe for a smaller scale, home audio drivers offer more finesse... but if you crave a big, relaxed, live sound, pro drivers may be the better choice.
The Alpha 15's in H-frames ROCK in my room. They are full, rich and effortless. If their big brothers are better that's great... something to look forward to as a future upgrade. For now, i'm just enjoying music again.
Haha me neither!!!
I'm all over my collection at the moment. Fortunately my 16,000 (and counting) tracks are all stored, lossless, on hard drives. But my 100+ LP's are all over the place
First thing I'm gonna do once the boxes are built is hire a big old hall and give em a good run in and tweek em up.
Speaking of cabinets.....
Would it be better to have the drivers offset from centre on the front of the cabinets? My thinking is that if the drivers are different distances from the nearest side, top & bottom of the cabinets (maybe 10cm from the top, 13cm from the nearest side and 22 from the bottom) that would help with reflections.
I'm gonna zip tie some felt or something to the inside of the chassis legs and then calk the outside. I'll also be inserting a bracing frame into the cabinets to help with panel flex.
Some more funny ideas - how about cutting up waste wood into odd lengths and gluing little random collections of it around the cabinet? Or using long threaded rod to pull the driver into the front baffle and butterfly nut tightened at the back of the cabinet? I have pondered using a large threaded metal rod to tie the front and back together. What thinks you?
Any useful reading or info/help on cabinet stuffing would be much appreciated as well.
My woodworking skills are basic but the way i tie the back and front of the box together is with a brace front to back.
The bottom screw holding the driver in place on the front baffle goes into the brace which connects to the back of the box... which is glued and screwed in place.
Sounds like you want to apply pressure to the back of the magnet with a screw (rod). I would imagine it could only help by preventing the driver from possibly wiggling around or vibrating.
Too complicated for me lol... my baffle is doubled where the screws go in so i don't think the driver is able to move but maybe removing any and all vibrations might help with micro details? I'd rope caulk the basket when i remove the drivers to finish the cabs. I still have not applied the 98 cent tweak but will eventually get around to that too... and the phase plug should be a fun experiment especially since the charts suggested further smoothing.
I did notice that heavily stuffing the cabinet with acousta stuff seemed to clean up the sound compared to a more lightly stuffed box. There was more of a souty sound with the boxes less stuffed. My boxes are now fully stuffed so the drivers magnet pushes into the fiber fill. I'd imagine the back wave is being absorbed more fully this way preventing it from disturbing the driver from the rear.
Part of my CD collection is on a hard drive... i need to copy the rest... more work to do!
Oh, and i have no preference on offsetting the drivers. There was not enough room on my baffles to do anything but center the 12lta... i doubt it will make much difference, so choose whatever suits your fancy and enjoy.
The bottom screw holding the driver in place on the front baffle goes into the brace which connects to the back of the box... which is glued and screwed in place.
Sounds like you want to apply pressure to the back of the magnet with a screw (rod). I would imagine it could only help by preventing the driver from possibly wiggling around or vibrating.
Too complicated for me lol... my baffle is doubled where the screws go in so i don't think the driver is able to move but maybe removing any and all vibrations might help with micro details? I'd rope caulk the basket when i remove the drivers to finish the cabs. I still have not applied the 98 cent tweak but will eventually get around to that too... and the phase plug should be a fun experiment especially since the charts suggested further smoothing.
I did notice that heavily stuffing the cabinet with acousta stuff seemed to clean up the sound compared to a more lightly stuffed box. There was more of a souty sound with the boxes less stuffed. My boxes are now fully stuffed so the drivers magnet pushes into the fiber fill. I'd imagine the back wave is being absorbed more fully this way preventing it from disturbing the driver from the rear.
Part of my CD collection is on a hard drive... i need to copy the rest... more work to do!
Oh, and i have no preference on offsetting the drivers. There was not enough room on my baffles to do anything but center the 12lta... i doubt it will make much difference, so choose whatever suits your fancy and enjoy.
Hi,
Neither. Use a Speaker level feed to the Subs, UNLESS you are fully active (which I do not recommend with full range drivers).
Ciao T
Neither. Use a Speaker level feed to the Subs, UNLESS you are fully active (which I do not recommend with full range drivers).
Ciao T
http://www.diyaudio.com/forums/multi-way/123512-ultimate-ob-gallery-48.html
Scroll down a bit to see how someone handled their subwoofer amp. I love the handle on top. I am going to do the same thing with my sub amp. Just a suggestion.
Zilla
Scroll down a bit to see how someone handled their subwoofer amp. I love the handle on top. I am going to do the same thing with my sub amp. Just a suggestion.
Zilla
So.... Amps near the sub enclosure but wired to the hi level input? 'zilla I like that idea
Can I ask why its best to use the hi level inputs? I thought that was best if using the other speaker outputs on the sub amps
Hi,
First, the highpass outputs from the Subamp are usually filtered and rarely if ever the way you would want it done.
Especially with a driver like the EB12LTA you do not need to do a lot to protect the driver from bass (unlike those girly man 4" & 5" 'Fullrange' Drivers. If you have the box sealed you already have a nice 2nd order rolloff, on an open baffle it will be 3rd order, with a vented box 4th order. You really do not want add to that slope unless essential.
Second, each and every amp is imperfect. The imperfections make themselves known in the signal to the driver full range driver. Anything that falls into the low frequency range gets picked up by the sub-amp. This is less obvious with solid state amp's, but even there you can hear two amp's playing two tunes if you do it the other way around.
It is easy enough to try out.
Ciao T
First, the highpass outputs from the Subamp are usually filtered and rarely if ever the way you would want it done.
Especially with a driver like the EB12LTA you do not need to do a lot to protect the driver from bass (unlike those girly man 4" & 5" 'Fullrange' Drivers. If you have the box sealed you already have a nice 2nd order rolloff, on an open baffle it will be 3rd order, with a vented box 4th order. You really do not want add to that slope unless essential.
Second, each and every amp is imperfect. The imperfections make themselves known in the signal to the driver full range driver. Anything that falls into the low frequency range gets picked up by the sub-amp. This is less obvious with solid state amp's, but even there you can hear two amp's playing two tunes if you do it the other way around.
It is easy enough to try out.
Ciao T
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