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Post by sq225917 on Jul 22, 2019 17:21:15 GMT
They're a lovely looking thing, smacks of being a labour of love refined over many decades. Match em up with an active 12" is a split sealed cab and have at it.
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Post by karma67 on Jul 22, 2019 17:42:28 GMT
there are a few options for this driver,im leaning towards this design,its by coral so perhaps the best one to go for although they produced a few,back loaded horn,bass reflex and a sealed cab version.
the above would look lovely i reckon in maple or birds eye maple veneer. geoff if you see this post can you comment on the cabs you made,they were different i think wern't they? bass reflex? this is all a bit 'in at the deep end' for me,the woodworks no problem but the principles of the horn and tunning is very out of my comfort zone,i thinks its best to make the cabs out of mdf first and screw the lot together and see how it works in my room,i wonder what effect varying the mouth of the horn just behind the driver magnet has?
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Post by macca on Jul 22, 2019 18:03:11 GMT
Same idea as the Lowther Acoustas. Will need to be right in the corners to get any bass at all. I'd go with the air tight or the bass reflex myself.
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Post by karma67 on Jul 22, 2019 18:07:21 GMT
Same idea as the Lowther Acoustas. Will need to be right in the corners to get any bass at all. I'd go with the air tight or the bass reflex myself. you mean the blh cabs? i thought the horn boosts the bass response? i should add i know f all about these design and what they do lol |
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Post by macca on Jul 22, 2019 18:17:06 GMT
The horn loading gives you massive efficiency so you can use a 4 watt single ended amplifier and fill a big hall. But you don't get any deep bass at all. You really own only get down to the low midrange even with the bastards stuck right in the corners and angled out. Whole chunks of some familiar recordings are missing entirely. You'll get fed up with it. I did anyway. On the other hand build a couple of tapped horns to go with them and you'd be onto something www.instructables.com/id/Building-a-tapped-horn/ |
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Post by macca on Jul 22, 2019 18:39:13 GMT
To summarise:
Air tight will give the deepest bass as it will roll off very slowly, if the cab is big enough.
Ported will give you higher bass levels but will roll off very quickly so won't go as low as the air tight but will be perceived as having more bass.
Some argue that ported bass is not as good as sealed cab bass. In terms of timing, coherence etc. They are right in some situations but imo with a well designed large speaker it becomes a non-issue.
Horn gives the least bass but massively high efficiency.
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Post by karma67 on Jul 22, 2019 18:43:40 GMT
To summarise: Air tight will give the deepest bass as it will roll off very slowly, if the cab is big enough. Ported will give you higher bass levels but will roll off very quickly so won't go as low as the air tight but will be perceived as having more bass. Some argue that ported bass is not as good as sealed cab bass. In terms of timing, coherence etc. They are right in some situations but imo with a well designed large speaker it becomes a non-issue. Horn gives the least bass but massively high efficiency. ah nice one,so really a blh is the last thing i should consider with my amp, (115 watts). now excuse my ignorance but if i went with a sealed cabinet does what your saying apply more to a seperate bass driver or does it still apply to a full range driver?
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Post by Deleted on Jul 22, 2019 18:56:35 GMT
To summarise: Air tight will give the deepest bass as it will roll off very slowly, if the cab is big enough. Ported will give you higher bass levels but will roll off very quickly so won't go as low as the air tight but will be perceived as having more bass. Some argue that ported bass is not as good as sealed cab bass. In terms of timing, coherence etc. They are right in some situations but imo with a well designed large speaker it becomes a non-issue. Horn gives the least bass but massively high efficiency. Sealed cabinet won't work unless it's ludicrously big, as the driver is very highly damped electrically/magnetically. Using it in a sealed box would give similar results to using a Lowther driver in a sealed box. Basically, it don't work! Ported will work well if it's big enough. BLH gives dramatic results with this driver, but there's no bass output below about 40Hz, not that there's much need for bass extending deeper on most music. I loved mine. Built using the Coral design. Quarter wave horn can give deeper bass, but a suitable design may be tricky to track down. Acoustic column is another option, but it would be BIG! Transmission line won't work well and give simlarly top biased results to the sealed box. |
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Post by macca on Jul 22, 2019 19:07:35 GMT
To summarise: Air tight will give the deepest bass as it will roll off very slowly, if the cab is big enough. Ported will give you higher bass levels but will roll off very quickly so won't go as low as the air tight but will be perceived as having more bass. Some argue that ported bass is not as good as sealed cab bass. In terms of timing, coherence etc. They are right in some situations but imo with a well designed large speaker it becomes a non-issue. Horn gives the least bass but massively high efficiency. ah nice one,so really a blh is the last thing i should consider with my amp, (115 watts). now excuse my ignorance but if i went with a sealed cabinet does what your saying apply more to a seperate bass driver or does it still apply to a full range driver?
Doesn't matter about power of the amp, you'll just need to use a lot less of the 115 watts with the horns  Yes, what I have said above applies to the separate bass driver too. All the designs you have posted just use the one full range driver though. Finding a design that uses both would be good, although I'm guessing that is the one you already have. Geoff - I'm assuming that the driver will work acceptably with a sealed cab as there is a design for one on the plans posted above. Although I can't tell how big it is as the image is too small I'm guessing it will be 80-100 litres or so |
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Post by karma67 on Jul 22, 2019 19:30:59 GMT
for the sealed cab they state 2 sizes. width= 660 depth=470 height=900 and smaller one, width=550 depth=380 height=750 the bass reflex design is, width=500 depth=400 height=670 all in mm
the sealed cabs they are in now are, width=375 depth=285 height=660
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Post by Deleted on Jul 22, 2019 19:39:12 GMT
The existing cabinets are a type of reflex box, the ABR acts as the port.
Any sealed box will be a serious compromise with the Betas. I wouldn't even consider it personally.
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Post by macca on Jul 22, 2019 21:36:38 GMT
for the sealed cab they state 2 sizes. width= 660 depth=470 height=900 and smaller one, width=550 depth=380 height=750 the bass reflex design is, width=500 depth=400 height=670 all in mm
the sealed cabs they are in now are, width=375 depth=285 height=660
So I was way off, they are big cabs, 279 litres for the sealed box, 157 for the ported one. Tasty! |
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Post by karma67 on Aug 4, 2019 14:09:13 GMT
hi, so the dats software turned up today and i set about measuring the drives,i measured them with the cones facing upwards,i hope thats right? maybe i should make some stands so they sit in them? anyway here's what i got, 1st driver.
2nd driver,
now even with my limited knowledge i can see one measures different to the other,how far apart or how bad that is i will leave to you to tell me. one other good thing that this software has is an inbuilt oscilloscope mode.
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Post by Deleted on Aug 4, 2019 20:33:41 GMT
hi, so the dats software turned up today and i set about measuring the drives,i measured them with the cones facing upwards,i hope thats right? maybe i should make some stands so they sit in them? anyway here's what i got, 1st driver.
2nd driver,
now even with my limited knowledge i can see one measures different to the other,how far apart or how bad that is i will leave to you to tell me. one other good thing that this software has is an inbuilt oscilloscope mode.
How did you measure the cones Jamie? What's the process. Sorry if it should be obvious but I didn't even know you could do it at home lol |
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Post by karma67 on Aug 5, 2019 15:49:07 GMT
very easy oli,you just connect the red and black leads to the speaker terminals on the driver and click 'measure free air perameters' the software produces a tone and it records the t/s figures.
the software also has an oscilloscope and can also measure resistors,capacitors (esr),test inductors and perform a rub test on driver cones,theres lots more but ive only just started using it.
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Post by sq225917 on Aug 5, 2019 16:44:54 GMT
Driver and mic location needs to be matched within a few mm for near field measurements. That might account for your differences. You'll need a jig to ensure repeatability.
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Post by karma67 on Aug 5, 2019 16:46:42 GMT
Driver and mic location needs to be matched within a few mm for near field measurements. That might account for your differences. You'll need a jig to ensure repeatability. hi si,the software doesn't use a mic,i plan to make a jig tomorrow at work to mount them properly. |
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Post by Deleted on Aug 5, 2019 17:59:27 GMT
very easy oli,you just connect the red and black leads to the speaker terminals on the driver and click 'measure free air perameters' the software produces a tone and it records the t/s figures. the software also has an oscilloscope and can also measure resistors,capacitors (esr),test inductors and perform a rub test on driver cones,theres lots more but ive only just started using it. w Just had a look. It's cool but I have no idea what the lines mean lol. |
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Post by dsjr on Aug 5, 2019 18:19:24 GMT
How old are these drivers again?
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Post by Deleted on Aug 5, 2019 18:26:52 GMT
How old are these drivers again? Circa 1979. |
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Post by karma67 on Aug 5, 2019 18:35:46 GMT
very easy oli,you just connect the red and black leads to the speaker terminals on the driver and click 'measure free air perameters' the software produces a tone and it records the t/s figures. the software also has an oscilloscope and can also measure resistors,capacitors (esr),test inductors and perform a rub test on driver cones,theres lots more but ive only just started using it. w Just had a look. It's cool but I have no idea what the lines mean lol. what makes you think i do? lol |
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Post by Deleted on Aug 5, 2019 18:37:45 GMT
w Just had a look. It's cool but I have no idea what the lines mean lol. what makes you think i do? lol Hahaha, I love it. |
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