I miss the WUMPABILITY of my old 15inch Tannoy DC's but these are in another league efficiency wise 
Been blowing the wind round the house with em all day and loving the grunt. Low bass? No. Thwack of the string on a bass guitar? yup
Can't wait to get their bigger brothers in situ and bringing up the lower octaves...
Been blowing the wind round the house with em all day and loving the grunt. Low bass? No. Thwack of the string on a bass guitar? yup
Can't wait to get their bigger brothers in situ and bringing up the lower octaves...
Could you give me some more info on your H-frames? Might help with the issue of the HUGE box my 15" will need!
What about a 100-120 mm vent on the front baffle? I have found empirically and through bass box 6 that almost every time this gives F3 of 45-47 hz and 35@-6 or 31@-10 with 80-100 l boxes. You can just keep the stuffing above the port and add a BSC.
Love that live/repetition room sound!
How are the solo drums? Punch in the face? (Hopefully)
Happy new year!
Love that live/repetition room sound!
How are the solo drums? Punch in the face? (Hopefully)
Happy new year!
H-frame
http://www.quarter-wave.com/OBs/U_and_H_Frames.pdf
I use mine with a dedicated amp. Small 'boxes' about as big as the driver... big bass.
http://www.quarter-wave.com/OBs/U_and_H_Frames.pdf
I use mine with a dedicated amp. Small 'boxes' about as big as the driver... big bass.
More listening tonight and tho my music loving friends really enjoyed the system and complimented the sound (tony bennet, simon and garfunkle and beethoven's ninth... all 22 minutes of it, lol) i did notice a few challenges to try and overcome.
The overall presentation is full and rich from top to bottom (H-frames connected)... comments like, "i never heard a piano sound this real thru a stereo"... or "there's something tangible here that i don't get thru my stereo"... and "can you help me build something like this?"
But, i noticed a shouty quality when the volume went up and a bit of congestion on complicated passages. So i want to tweak. I think the dustcap will come off and i will listen a while... maybe damar and some kind of mass loading on the cone to minimize some of the break up... The drivers are good as is but i think things can be improved.
Zilla
The overall presentation is full and rich from top to bottom (H-frames connected)... comments like, "i never heard a piano sound this real thru a stereo"... or "there's something tangible here that i don't get thru my stereo"... and "can you help me build something like this?"
But, i noticed a shouty quality when the volume went up and a bit of congestion on complicated passages. So i want to tweak. I think the dustcap will come off and i will listen a while... maybe damar and some kind of mass loading on the cone to minimize some of the break up... The drivers are good as is but i think things can be improved.
Zilla
Hi,
My original Goodmans (Axiom 201) loaded Afterburners did use subwoofers (and of course super-tweeters). If a Sub is needed or not depends a lot on the music one listens to and on expectations.
Next to (for arguments sake) a pair of BBC LS3/5 the Afterburner's are rather "bass-monsters"...
Nice to see that my old project still makes occasional waves.
I think in this day age there are better projects, but in around Y2K there was not lot choice available.
Ciao T
My original Goodmans (Axiom 201) loaded Afterburners did use subwoofers (and of course super-tweeters). If a Sub is needed or not depends a lot on the music one listens to and on expectations.
Next to (for arguments sake) a pair of BBC LS3/5 the Afterburner's are rather "bass-monsters"...
Nice to see that my old project still makes occasional waves.
I think in this day age there are better projects, but in around Y2K there was not lot choice available.
Ciao T
I am wondering if a foam insert fitted for the 12lta would improve their performance. I noticed Gedlee uses them for his tweeters.
Summa
I wish there was a easy way to try this out. I'd want to mount it within the whizzer before cutting out the dustcap. I want to soak up high frequencies that are emanating from the center of the driver. Any ideas to accomplish this?
Thanks,
Zilla
Summa
I wish there was a easy way to try this out. I'd want to mount it within the whizzer before cutting out the dustcap. I want to soak up high frequencies that are emanating from the center of the driver. Any ideas to accomplish this?
Thanks,
Zilla
Dave (Planet10) tells me that the phase plugs are 44mm Diameter, Height 62.5mm, length of barral/straight part 38mm before turning to the point.
This should do more than the foam shouldn't it?
Mine are starting to sound rather nice. Really good on vocals but still a touch shouty.
I've been reading up on various threads on directivity of horns and wonder if a nice wide horn would suit my system. I don't really want to spend £$£$£ on the FT17H's and then want more.
What think you?
This should do more than the foam shouldn't it?
Mine are starting to sound rather nice. Really good on vocals but still a touch shouty.
I've been reading up on various threads on directivity of horns and wonder if a nice wide horn would suit my system. I don't really want to spend £$£$£ on the FT17H's and then want more.
What think you?
Gedlee places the open cell foam in the interior of the his tweeter wave guides (horns). The foam does not physically contact the driver diaphram. The foam absorbs reflections off the horn/waveguide walls. It would do the same inside the whizzer of your 12LTA's, but would also add some mass which could alter (decrease) the sensitivity and extension of the whizzer. A small amount might still be more beneficial than degrading. Seems worth a try. It would be similar to the $0.99 solution for Lowthers (and other high efficiency, wide range drivers): placing a little polyester fiber between the main cone and whizzer (that might also be worth a try!). Let us know how it turns out.
Bob
Thanks for the suggestions! Maybe i can loosley wad up some acousta stuff inside the whizzer and see if it makes a positive difference in sound... just need to figure a way to keep it inside the cone. I was also thinking about removing the dustcap and adding a wooden dowel with a piece of acoustic foam on the tip so not to add mass to the driver. I will also do the 99 cent tweak.
Crossover?
Right now i am running the 12lta full out without any crossover. The tweeter is simply connected to a 1uf cap. Originally it was a 1.5uf but i changed it to reduce treble. I may add a coil for a 12db rolloff but for now the cap is sufficient until i figure out the 12lta. I brought a few fresh Xacto blades home last night for cutting out one of the dustcaps on the 12lta. Then i will listen to see how it sounds different than the stock driver. Then i will add acousta stuff around the whizzer and listen some more. As for the bass... i will simply connect a powered subwoofer and blend with the dials on the sub amp.
Anyone have any thoughts on using the circuit on the Afterburner project vs letting the driver run full out? I've read here and there some like i with and some without.
Thanks,
Zilla
Right now i am running the 12lta full out without any crossover. The tweeter is simply connected to a 1uf cap. Originally it was a 1.5uf but i changed it to reduce treble. I may add a coil for a 12db rolloff but for now the cap is sufficient until i figure out the 12lta. I brought a few fresh Xacto blades home last night for cutting out one of the dustcaps on the 12lta. Then i will listen to see how it sounds different than the stock driver. Then i will add acousta stuff around the whizzer and listen some more. As for the bass... i will simply connect a powered subwoofer and blend with the dials on the sub amp.
Anyone have any thoughts on using the circuit on the Afterburner project vs letting the driver run full out? I've read here and there some like i with and some without.
Thanks,
Zilla
Thanks for covering your build in detail, GZ. Does anyone have distortion plots of the Beta 12? I'm curious to see what it's really putting out. I've seen the FR plots, and I'm always a little put off by the rising hump above 1-2kHz.
If you can accept a HUGE cabinet, it seems a great driver for bass. I'm just wondering if someone tried it in more of a FAST arrangement, using a very small full-ranger (or tweeter that goes REALLY low) to cross lower?
If you can accept a HUGE cabinet, it seems a great driver for bass. I'm just wondering if someone tried it in more of a FAST arrangement, using a very small full-ranger (or tweeter that goes REALLY low) to cross lower?
I was looking at the afterburner/hammer dynamics crossovers last night and to be perfectly honest they are WAY more complex than I want on what is essentially a full range project
I bastardised 2 cupboards in my living room and mounted them up. They're not even properly sealed but damn are they good. I think 6 or 12 on the tweeter and a sub per side will do it.
I've ordered 2 of the Foster sub amps and am awaiting them arriving at a friends place in Tucson. Then on to me. My Beta 15's are en route as well.
Frankly I'm blown away by how good these drivers sound. I think they are coloured, but I have nothing to reference them against apart from my ears and right now they are telling me they are really good
I bastardised 2 cupboards in my living room and mounted them up. They're not even properly sealed but damn are they good. I think 6 or 12 on the tweeter and a sub per side will do it.
I've ordered 2 of the Foster sub amps and am awaiting them arriving at a friends place in Tucson. Then on to me. My Beta 15's are en route as well.
Frankly I'm blown away by how good these drivers sound. I think they are coloured, but I have nothing to reference them against apart from my ears and right now they are telling me they are really good
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All I can tell you is that what comes out of them 'sounds' real. I really wouldn't worry too much about distortion. If it sounds good in your room then it sounds good.
Even live performances are distorted in some ways. Maybe by the 3 rows of peoples heads in front of you, while being too close to the right hand wall gives you funky early reflections from the dudes in the brass section and the venue seem to have amped a hole in the midrange.......
Spend a few bucks and I promise you, you wont be disapointed
I think we can make this a simple three way without any complicated circuits. It may not be the ultimate in performance but it's already very good on its own and has qualities other types of systems just don't have, like very high eff, dynamics, etc... Foster sub or Beta 15... you should have great bass. But what tweeter will you be using?
shoutiness
The beta 12 has a rising response in the (from memory, been awhile) range of 700-800 hz on out to around 1500, while contributes to the shoutiness. I tried it initially w/o a notch filter, felt it sounded much better with a filter. I used the values TL posted in the original article, as well as the zoeble. Tweeter is crossed with a simple cap only (1.5U), no padding. These drivers seem really prone to internal box reflections finding their way out via the thin paper, so they benefit from a well braced, damped box. I used the bubble wrap and plastic peanuts ala hammer dynamics, as well as the heavy felt blanket from Thorsten's site. This helped with the shoutiness a lot, then later I improved the internal bracing of the box, and this seemed to help as much as anything else. Mine have very good bass, even when driven with flea powerwed amps. If you are driving with solid state, you may improve the bass by adding a few ohms between amp and speaker
The beta 12 has a rising response in the (from memory, been awhile) range of 700-800 hz on out to around 1500, while contributes to the shoutiness. I tried it initially w/o a notch filter, felt it sounded much better with a filter. I used the values TL posted in the original article, as well as the zoeble. Tweeter is crossed with a simple cap only (1.5U), no padding. These drivers seem really prone to internal box reflections finding their way out via the thin paper, so they benefit from a well braced, damped box. I used the bubble wrap and plastic peanuts ala hammer dynamics, as well as the heavy felt blanket from Thorsten's site. This helped with the shoutiness a lot, then later I improved the internal bracing of the box, and this seemed to help as much as anything else. Mine have very good bass, even when driven with flea powerwed amps. If you are driving with solid state, you may improve the bass by adding a few ohms between amp and speaker
I tried this with the whizzer on an AN8. I had it stuffed with polyfiber (from walmart) between the whizzer and the main cone. The AN8 has two nasty peaks at 3kHz and 4.5 kHz. The 3kHz resonance was reduced substantially with the stuffing.
Next, tried the open cell foam on the whizzer center. I'm not sure it is exactly what Geddes uses, but it simply worked like a charm. It knocks out the huge response peak near 12 kHz (which makes the 'sssss' sound really bad) while leaving the rest of the spectrum as it was. The only negative was an apparent delay in the high frequencies. Basically, it did not sound as coherent with the foam.
Just my 2c.
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